Recent zbMATH articles in MSC 68https://zbmath.org/atom/cc/682024-04-15T15:10:58.286558ZUnknown authorWerkzeugThe mathematics that power our world. How is it made?https://zbmath.org/1530.000072024-04-15T15:10:58.286558Z"Khoury, Joseph"https://zbmath.org/authors/?q=ai:khoury.joseph"Lamothe, Gilles"https://zbmath.org/authors/?q=ai:lamothe.gillesPublisher's description: This book is an attempt to unveil the hidden mathematics behind the functioning of many of the devices we use on a daily basis. For the past years, discussions on the best approach in teaching and learning mathematics have shown how much the world is divided on this issue. The one reality we seem to agree on globally is the fact that our new generation is lacking interest and passion for the subject. One has the impression that the vast majority of young students finishing high school or in their early post-secondary studies are more and more divided into two main groups when it comes to the perception of mathematics. The first group looks at mathematics as a pure academic subject with little connection to the real world. The second group considers mathematics as a set of tools that a computer can be programmed to use and thus, a basic knowledge of the subject is sufficient. This book serves as a middle ground between these two views. Many of the elegant and seemingly theoretical concepts of mathematics are linked to state-of-the-art technologies. The topics of the book are selected carefully to make that link more relevant. They include: digital calculators, basics of data compression and the Huffman coding, the JPEG standard for data compression, the GPS system studied both from the receiver and the satellite ends, image processing and face recognition.
This book is a great resource for mathematics educators in high schools, colleges and universities who want to engage their students in advanced readings that go beyond the classroom discussions. It is also a solid foundation for anyone thinking of pursuing a career in science or engineering. All efforts were made so that the exposition of each topic is as clear and self-contained as possible and thus, appealing to anyone trying to broaden his mathematical horizons.Book review of: W. B. Powell, Reinforcement learning and stochastic optimization. A unified framework for sequential decisionshttps://zbmath.org/1530.000092024-04-15T15:10:58.286558Z"Halperin, Igor"https://zbmath.org/authors/?q=ai:halperin.igorReview of [Zbl 1522.91005].Foreword to the special focus on advances in symbolic and numeric computation. III.https://zbmath.org/1530.000252024-04-15T15:10:58.286558ZFrom the text: The present Special Focus of Mathematics in Computer Science is connected to SYMCOMP2019, the 4th International Conference on Numerical and Symbolic Computation: Developments and Applications, which was held on April 11--12, 2019, in Porto, Portugal.
For Parts I--II see [Zbl 1356.00057; Zbl 1407.00044].Prefacehttps://zbmath.org/1530.000282024-04-15T15:10:58.286558ZFrom the text: This Special Issue of Computers \& Mathematics with Applications entitled ``Scientific machine learning: blending of traditional mechanistic modeling with machine learning methodologies'' stems from the shared research interests of the guest editors in merging classical scientific computing techniques with modern machine learning tools. The collection features nine contributions that delve into various aspects of methodology and
applications within the realm of scientific machine learning. Topics covered include reduced-order modeling, operator inference, physics-informed neural networks, adversarial neural networks, closure models, and uncertainty quantification.Foreword, with a dedication to Andreas Weberhttps://zbmath.org/1530.000372024-04-15T15:10:58.286558ZFrom the text: The International Workshop on Computer Algebra in Scientific Computing (CASC) is an annual conference on Computer Algebra Systems, the underlying algorithms for Symbolic Computation, and the role of both within Scientific Computation and its applications. In 2019 the 21st CASC conference was held in Moscow, Russia, hosted by the Plekhanov Russian University of Economics. This special issue of Mathematics in Computer Science contains selected work that was presented at the conference.Forewordhttps://zbmath.org/1530.000412024-04-15T15:10:58.286558ZFrom the text: The International Symposium on Symbolic and Algebraic Computation (ISSAC) is the premier conference for research in symbolic computation and computer algebra. ISSAC 2018, held at the City University of New York in New York City, USA, was the 43rd meeting in the series, which began in 1966 with the seminal ACM Symposium on Symbolic and Algebraic Manipulation.Eric Goleshttps://zbmath.org/1530.010232024-04-15T15:10:58.286558Z"Adamatzky, Andrew"https://zbmath.org/authors/?q=ai:adamatzky.andrew-iThe author gives an account of life and work of Eric Goles, who contributed decisively to the areas of unconventional computing models and complex systems.
For the entire collection see [Zbl 1485.68009].Words, history and mathematicshttps://zbmath.org/1530.010482024-04-15T15:10:58.286558Z"Lê, François"https://zbmath.org/authors/?q=ai:le.francoisSummary: This article presents some results obtained recently in the history of mathematics using the tools of textometry. The results pertain to two case-studies, devoted to Charles Hermite's style and to the theory of algebraic surfaces at the end of the 19th century, respectively.Elements of formal semantics. An introduction to the mathematical theory of meaning in natural languagehttps://zbmath.org/1530.030082024-04-15T15:10:58.286558Z"Winter, Yoad"https://zbmath.org/authors/?q=ai:winter.yoadPublisher's description: In formal semantics, structure is treated as the essential ingredient in the creation of sentence meaning from individual word meaning. This book introduces some of the foundational concepts, principles and techniques in the formal semantics of natural language and outlines the mathematical principles that underlie linguistics meaning. Using English examples, Yoad Winter presents the most useful tools and concepts of formal semantics in an accessible style and includes a variety of practical exercises so that readers can learn to utilize these tools effectively. For readers with an elementary background in set theory and linguistics or with an interest in mathematical modelling, this fascinating study is an ideal introduction to natural language semantics. Designed as a quick yet thorough introduction to one of the most vibrant areas of research in modern linguistics today this volume reveals the beauty and elegance of the mathematical study of meaning.A note on \(\mathbb{C}^2\) interpreted over finite data-wordshttps://zbmath.org/1530.030492024-04-15T15:10:58.286558Z"Bednarczyk, Bartosz"https://zbmath.org/authors/?q=ai:bednarczyk.bartosz"Witkowski, Piotr"https://zbmath.org/authors/?q=ai:witkowski.piotrSummary: We consider the satisfiability problem for the two-variable fragment of first-order logic extended with counting quantifiers, interpreted over finite words with data, denoted here with \(\mathbb{C}^2[\leq,\text{succ},\sim,\pi_{\text{bin}}]\). In our scenario, we allow for using arbitrary many uninterpreted binary predicates from \(\pi_{\text{bin}}\), two navigational predicates \(\leq\) and succ over word positions as well as a data-equality predicate \(\sim\). We prove that the obtained logic is undecidable, which contrasts with the decidability of the logic without counting by \textit{A. Montanari} et al. [Acta Inf. 53, No. 6--8, 621--648 (2016; Zbl 1350.68185)]. We supplement our results with decidability for several sub-fragments of \(\mathbb{C}^2[\leq,\text{succ},\sim, \pi_{\text{bin}}]\), e.g. without binary predicates, without successor succ, or under the assumption that the total number of positions carrying the same data value in a data-word is bounded by an a priori given constant.
For the entire collection see [Zbl 1443.68018].On the decidability of a fragment of preferential LTLhttps://zbmath.org/1530.030502024-04-15T15:10:58.286558Z"Chafik, Anasse"https://zbmath.org/authors/?q=ai:chafik.anasse"Cheikh-Alili, Fahima"https://zbmath.org/authors/?q=ai:cheikh-alili.fahima"Condotta, Jean-François"https://zbmath.org/authors/?q=ai:condotta.jean-francois"Varzinczak, Ivan"https://zbmath.org/authors/?q=ai:varzinczak.ivan-joseSummary: Linear Temporal Logic (LTL) has found extensive applications in Computer Science and Artificial Intelligence, notably as a formal framework for representing and verifying computer systems that vary over time. Non-monotonic reasoning, on the other hand, allows us to formalize and reason with exceptions and the dynamics of information. The goal of this paper is therefore to enrich temporal formalisms with non-monotonic reasoning features. We do so by investigating a preferential semantics for defeasible LTL along the lines of that extensively studied by \textit{S. Kraus} et al. [Artif. Intell. 44, No. 1--2, 167--207 (1990; Zbl 0782.03012)] in the propositional case and recently extended to modal and description logics. The main contribution of the paper is a decidability result for a meaningful fragment of preferential LTL that can serve as the basis for further exploration of defeasibility in temporal formalisms.
For the entire collection see [Zbl 1443.68018].Codifying guarded definitions with recursive schemeshttps://zbmath.org/1530.030542024-04-15T15:10:58.286558Z"Giménez, Eduarde"https://zbmath.org/authors/?q=ai:gimenez.eduardeSummary: We formalize an extension of the Calculus of Constructions with inductive and coinductive types which allows a more direct description of recursive definitions. The approach we follow is close to the one proposed for Martin-Löf's type theory in [\textit{T. Coquand}, Lect. Notes Comput. Sci. 806, 62--78 (1994; Zbl 1527.03008)]. Recursive objects can be defined by fixed-point definitions as in functional programming languages, and a syntactical checking of these definitions avoids the introduction of non-normalizable terms. We show that the conditions for accepting a recursive definition proposed in [loc. cit.] are not sufficient for the Calculus of Constructions, and we modify them. As a way of justifying our conditions, we develop a general method to codify a fix point definition satisfying them using well-known recursive schemes, like primitive recursion and co-recursion. We also propose different reduction rules from the ones used in [loc. cit.] in order to obtain a decidable conversion relation for the system.
For the entire collection see [Zbl 0866.00037].One-pass context-based tableaux systems for CTL and ECTLhttps://zbmath.org/1530.030682024-04-15T15:10:58.286558Z"Abuin, Alex"https://zbmath.org/authors/?q=ai:abuin.alex"Bolotov, Alexander"https://zbmath.org/authors/?q=ai:bolotov.alexander"Hermo, Montserrat"https://zbmath.org/authors/?q=ai:hermo.montserrat"Lucio, Paqui"https://zbmath.org/authors/?q=ai:lucio.paquiSummary: When building tableau for temporal logic formulae, applying a two-pass construction, we first check the validity of the given tableaux input by creating a tableau graph, and then, in the second ``pass'', we check if all the eventualities are satisfied. In one-pass tableaux checking the validity of the input does not require these auxiliary constructions. This paper continues the development of one-pass tableau method for temporal logics introducing tree-style one-pass tableau systems for Computation Tree Logic (CTL) and shows how this can be extended to capture Extended CTL (ECTL). A distinctive feature here is the utilisation, for the core tableau construction, of the concept of a context of an eventuality which forces its earliest fulfilment. Relevant algorithms for obtaining a systematic tableau for these branching-time logics are also defined. We prove the soundness and completeness of the method. With these developments of a tree-shaped one-pass tableau for CTL and ECTL, we have formalisms which are well suited for the automation and are amenable for the implementation, and for the formulation of dual sequent calculi. This brings us one step closer to the application of one-pass context-based tableaux in certified model checking for a variety of CTL-type branching-time logics.
For the entire collection see [Zbl 1443.68018].Temporal logic with recursionhttps://zbmath.org/1530.030692024-04-15T15:10:58.286558Z"Bruse, Florian"https://zbmath.org/authors/?q=ai:bruse.florian"Lange, Martin"https://zbmath.org/authors/?q=ai:lange.martinSummary: We introduce extensions of the standard temporal logics CTL and LTL with a recursion operator that takes propositional arguments. Unlike other proposals for modal fixpoint logics of high expressive power, we obtain logics that retain some of the appealing pragmatic advantages of CTL and LTL, yet have expressive power beyond that of the modal \(\mu\)-calculus or MSO. We advocate these logics by showing how the recursion operator can be used to express interesting non-regular properties. We also study decidability and complexity issues of the standard decision problems.
For the entire collection see [Zbl 1443.68018].The complexity of multiplicative-additive Lambek calculus: 25 years laterhttps://zbmath.org/1530.030912024-04-15T15:10:58.286558Z"Kanovich, Max"https://zbmath.org/authors/?q=ai:kanovich.max-i"Kuznetsov, Stepan"https://zbmath.org/authors/?q=ai:kuznetsov.s-l"Scedrov, Andre"https://zbmath.org/authors/?q=ai:scedrov.andreSummary: The Lambek calculus was introduced as a mathematical description of natural languages. The original Lambek calculus is NP-complete (Pentus), while its product-free fragment with only one implication is polynomially decidable (Savateev). We consider Lambek calculus with the additional connectives: conjunction and disjunction. It is known that this system is PSPACE-complete (Kanovich, Kanazawa). We prove, in contrast with the polynomial-time result for the product-free Lambek calculus with one implication, that the derivability problem is still PSPACE-complete even for a very small fragment \((\backslash,\wedge)\), including one implication and conjunction only. PSPACE-completeness is also provided for the \((\backslash,\vee)\) fragment, which includes only one implication and disjunction. Categorial grammars based on the original Lambek calculus generate exactly the class of context-free languages (Gaifman, Pentus). The class of languages generated by Lambek grammars extended with conjunction is known to be closed under intersection (Kanazawa), and therefore includes all finite intersections of context-free languages and, moreover, images of such intersections under alphabetic homomorphisms. We show that the same closure under intersection holds for Lambek grammars extended with disjunction, even for our small \((\backslash,\vee)\) fragment.
For the entire collection see [Zbl 1418.03008].Gradability in MTT-semanticshttps://zbmath.org/1530.031202024-04-15T15:10:58.286558Z"Chatzikyriakidis, Stergios"https://zbmath.org/authors/?q=ai:chatzikyriakidis.stergios"Luo, Zhaohui"https://zbmath.org/authors/?q=ai:luo.zhaohuiSummary: In this paper, we look at the issue of gradability within formal semantics in modern type theories (MTT-semantics). Specifically, we look at both gradable adjectives and nouns, and show that the rich typing mechanisms afforded by MTT-semantics can give us a natural account of gradability. Gradable adjectives take indexed nouns as their arguments, while gradable nouns are \(\varSigma \)-types where their first projection is a degree parameter. Furthermore, we provide a standard polymorphic measure function applicable to all gradable adjectives and nouns. We also look at multidimensional adjectives and use enumerated types to capture multidimensionality. We formalize our account in the Coq proof assistant and check its formal correctness. Lastly, we briefly describe a recent proposal of model gradability by means of subtype universes in MTTs that can potentially give a unifying treatment of gradability for both regular gradable adjectives, but also multidimensional ones.
For the entire collection see [Zbl 1494.03010].Modal auxiliaries and negation: a type logical accounthttps://zbmath.org/1530.031262024-04-15T15:10:58.286558Z"Kubota, Yusuke"https://zbmath.org/authors/?q=ai:kubota.yusuke"Levine, Robert"https://zbmath.org/authors/?q=ai:levine.robert-ySummary: This paper proposes an analysis of modal auxiliaries in English in type logical grammar. The proposed analysis captures the scopal interactions between different types of modal auxiliaries and negation by incorporating the key analytic idea of \textit{S. Iatridou} and \textit{H. Zeijlstra} [``Negation, polarity, and deontic modals'', Linguist. Inq. 44, No. 4, 529--568 (2013; \url{doi:10.1162/LING_a_00138
})], who classify English modal auxiliaries into PPI and NPI types. In order to technically implement this analysis, we build on \textit{Y. Kubota} and \textit{R. Levine}'s [Lect. Notes Comput. Sci. 7351, 135--150 (2012; Zbl 1291.03056); ``Gapping as hypothetical reasoning'', Nat. Lang. Linguist. Theor. 34, No. 1, 107--156 (2016; \url{doi:10.1007/s11049-015-9298-4})] treatment of modal auxiliaries as higher-order operators that take scope at the clausal level. The proposed extension of the Kubota/Levine analysis is shown to have several interesting consequences, including a formal derivability relation from the higher-order entry for auxiliaries to a lower-order VP/VP entry traditionally recognized in categorial grammar (CG) research. The systematic analysis of the scopal properties of auxiliaries and the somewhat more abstract meta-comparison between `transformational' and `non-transformational' analytic ideas that become possible in a type-logical setup highlight the value of taking a logical perspective on the syntax of natural language embodied in type logical grammar research.
For the entire collection see [Zbl 1418.03008].A concrete final coalgebra theorem for ZF set theoryhttps://zbmath.org/1530.031522024-04-15T15:10:58.286558Z"Paulson, Lawrence C."https://zbmath.org/authors/?q=ai:paulson.lawrence-charlesSummary: A special final coalgebra theorem, in the style of \textit{P. Aczel}'s [Non-well-founded sets. Foreword by Jon Barwise. Stanford, CA: Center for the Study of Language and Information (1988; Zbl 0668.04001)], is proved within standard Zermelo-Fraenkel set theory. Aczel's Anti-Foundation Axiom is replaced by a variant definition of function that admits non-well-founded constructions. Variant ordered pairs and tuples, of possibly infinite length, are special cases of variant functions. Analogues of Aczel's Solution and Substitution Lemmas are proved in the style of \textit{J. J. M. M. Rutten} and \textit{D. Turi} [Lect. Notes Comput. Sci. 666, 477--530 (; \url{doi:10.1007/3-540-56596-5_45})]. The approach is less general than Aczel's, but the treatment of non-well-founded objects is simple and concrete. The final coalgebra of a functor is its greatest fixedpoint. The theory is intended for machine implementation and a simple case of it is already implemented using the theorem prover Isabelle [\textit{L. C. Paulson}, Lect. Notes Comput. Sci. 814, 148--161 (1994; Zbl 1433.68560)].
For the entire collection see [Zbl 0866.00037].A natural bijection for contiguous pattern avoidance in wordshttps://zbmath.org/1530.050022024-04-15T15:10:58.286558Z"Carrigan, Julia"https://zbmath.org/authors/?q=ai:carrigan.julia"Hollars, Isaiah"https://zbmath.org/authors/?q=ai:hollars.isaiah"Rowland, Eric"https://zbmath.org/authors/?q=ai:rowland.eric-sSummary: Two words \(p\) and \(q\) are avoided by the same number of length-\(n\) words, for all \(n\), precisely when \(p\) and \(q\) have the same set of border lengths. Previous proofs of this theorem use generating functions but do not provide an explicit bijection. We give a bijective proof for all pairs \(p\), \(q\) that have the same set of proper borders, establishing a natural bijection from the set of words avoiding \(p\) to the set of words avoiding \(q\).On Hofstadter's G-sequencehttps://zbmath.org/1530.050102024-04-15T15:10:58.286558Z"Dekking, F. M."https://zbmath.org/authors/?q=ai:dekking.michelSummary: We characterize the entries of Hofstadter's G-sequence in terms of the lower and upper Wythoff sequences. This can be used to give a short and comprehensive proof of the equality of Hofstadter's G-sequence and the sequence of averages of the swapped Wythoff sequences. In the second part, we give some results that hold when one replaces the golden mean by other quadratic algebraic numbers. In the third part we prove a close relationship between Hofstadter's G-sequence and a sequence studied by \textit{M. Avdispahić} and \textit{F. Zejnulahi} [Fibonacci Q. 58, No. 4, 321--327 (2020; Zbl 1473.11060)].Matroid Horn functionshttps://zbmath.org/1530.050212024-04-15T15:10:58.286558Z"Bérczi, Kristóf"https://zbmath.org/authors/?q=ai:berczi.kristof"Boros, Endre"https://zbmath.org/authors/?q=ai:boros.endre"Makino, Kazuhisa"https://zbmath.org/authors/?q=ai:makino.kazuhisaSummary: Hypergraph Horn functions were introduced as a subclass of Horn functions that can be represented by a collection of circular implication rules. These functions possess distinguished structural and computational properties. In particular, their characterizations in terms of implicate-duality and the closure operator provide extensions of matroid duality and the Mac Lane-Steinitz exchange property of matroid closure, respectively.
In the present paper, we introduce a subclass of hypergraph Horn functions that we call matroid Horn functions. We provide multiple characterizations of matroid Horn functions in terms of their canonical and complete CNF representations. We also study the Boolean minimization problem for this class, where the goal is to find a minimum size representation of a matroid Horn function given by a CNF representation. While there are various ways to measure the size of a CNF, we focus on the number of circuits and circuit clauses. We determine the size of an optimal representation for binary matroids, and give lower and upper bounds in the uniform case. For uniform matroids, we show a strong connection between our problem and Turán systems that might be of independent combinatorial interest.Exchange distance of basis pairs in split matroidshttps://zbmath.org/1530.050222024-04-15T15:10:58.286558Z"Bérczi, Kristóf"https://zbmath.org/authors/?q=ai:berczi.kristof"Schwarcz, Tamás"https://zbmath.org/authors/?q=ai:schwarcz.tamasSummary: The basis exchange axiom has been a driving force in the development of matroid theory. However, the axiom gives only a local characterization of the relation of bases, which is a major stumbling block to further progress, and providing a global understanding of the structure of matroid bases is a fundamental goal in matroid optimization. While studying the structure of symmetric exchanges, Gabow proposed the problem that any pair of bases admits a sequence of symmetric exchanges. A different extension of the exchange axiom was proposed by White, who investigated the equivalence of compatible basis sequences. These conjectures suggest that the family of bases of a matroid possesses much stronger structural properties than we are aware of. In the present paper, we study the distance of basis pairs of a matroid in terms of symmetric exchanges. In particular, we give a polynomial-time algorithm that determines a shortest possible exchange sequence that transforms a basis pair into another for split matroids, a class that was motivated by the study of matroid polytopes from a tropical geometry point of view. As a corollary, we verify the above-mentioned long-standing conjectures for this large class. As paving matroids form a subclass of split matroids, our result settles the conjectures for paving matroids as well.Further split graphs known to be class 1 and a characterization of subgraph-overfull split graphshttps://zbmath.org/1530.050392024-04-15T15:10:58.286558Z"Cararo, Cintia Izabel"https://zbmath.org/authors/?q=ai:cararo.cintia-izabel"Morais de Almeida, Sheila"https://zbmath.org/authors/?q=ai:de-almeida.sheila-morais"Nunes da Silva, Cândida"https://zbmath.org/authors/?q=ai:da-silva.candida-nunesSummary: The chromatic index, \(\chi^\prime (G)\), is the smallest integer \(k\) for which a graph \(G\) has a proper edge coloring. The Classification Problem involves determining whether a graph \(G\) is Class 1 \((\chi^\prime (G) = \varDelta (G))\) or Class 2 \((\chi^\prime (G) = \varDelta (G) + 1)\). It is known that subgraph-overfull graphs must be Class 2. In this paper we are concerned with the Classification Problem for split graphs \(G [Q \cup S]\) where \(Q\) is a clique and \(S\) is an independent set. When \(\varDelta (G)\) is odd, \(G\) is known to be Class 1. The original proof presented by \textit{B.-L. Chen} et al. [J. Comb. Math. Comb. Comput. 17, 137--146 (1995; Zbl 0819.05026)] has a minor flaw which we detail in this paper while also clarifying that it does not compromise their result. We prove that their technique can be adapted in a non-trivial way to show that some split graphs with even \(\varDelta (G)\) are also Class 1. We show that to solve the Classification Problem for split graphs it suffices to consider that all vertices in \(Q\) have degree \(\varDelta (G)\). Considering the subset \(X\) of \(S\) of the vertices of degree at most \(\varDelta (G) / 2\), we show that if the neighborhood of \(X\) has at least \(\lfloor |Q|/2 \rfloor\) vertices, then \(G\) is Class 1; in the remaining cases we characterize the subgraph-overfull split graphs.A rainbow about \(T\)-colorings for complete graphshttps://zbmath.org/1530.050442024-04-15T15:10:58.286558Z"Jansen, Klaus"https://zbmath.org/authors/?q=ai:jansen.klausSummary: Given a finite set \(T\) of positive integers, with \(0 \in T\), a \(T\)-coloring of a graph \(G = (V, E)\) is a function \(f: V \rightarrow \mathbb{N}_0\) such that for each \(\{x,y\} \in E\), \(|f(x) - f(y)| \notin T\). The \(T\)-span is the difference between the largest and smallest color and the \(T\)-span of \(G\) is the minimum span over all \(T\)-colorings of \(G\). We show that the problem to find the \(T\)-span for a complete graph is NP-complete.
For the entire collection see [Zbl 0825.00128].Quasi-Sturmian colorings on regular treeshttps://zbmath.org/1530.050472024-04-15T15:10:58.286558Z"Kim, Dong Han"https://zbmath.org/authors/?q=ai:kim.donghan.1"Lee, Seul Bee"https://zbmath.org/authors/?q=ai:lee.seul-bee"Lim, Seonhee"https://zbmath.org/authors/?q=ai:lim.seonhee"Sim, Deokwon"https://zbmath.org/authors/?q=ai:sim.deokwonSummary: Quasi-Sturmian words, which are infinite words with factor complexity eventually \(n+c\) share many properties with Sturmian words. In this article, we study the quasi-Sturmian colorings on regular trees. There are two different types, bounded and unbounded, of quasi-Sturmian colorings. We obtain an induction algorithm similar to Sturmian colorings. We distinguish them by the recurrence function.Coloring \(k\)-colorable graphs in constant expected parallel timehttps://zbmath.org/1530.050492024-04-15T15:10:58.286558Z"Kučera, Luděk"https://zbmath.org/authors/?q=ai:kucera.ludekSummary: A parallel (CRCW PRAM) algorithm is given to find a \(k\)-coloring of a graph randomly drawn from the family of \(k\)-colorable graphs with \(n\) vertices, where \(k = \log^{O(1)} n\). The average running time of the algorithm is constant, and the number of processors is equal to \(|V| + |E|\), where \(|V|\), \(|E|\), resp. is the number of vertices, edges, resp. of the input graph.
For the entire collection see [Zbl 0825.00128].Relations of three classes of disconnected coloringhttps://zbmath.org/1530.050512024-04-15T15:10:58.286558Z"Li, Ping"https://zbmath.org/authors/?q=ai:li.ping.32|li.ping.10|li.ping.25|li.ping.1|li.ping.4|li.ping.16|li.ping.26|li.ping.23|li.ping.8|li.ping.5|li.ping.2|li.ping|li.ping.7|li.ping.30Summary: For an edge-colored graph (resp. a vertex-colored graph), a subset of edges (resp. vertices) is called monochromatic if all elements are assigned the same color. An edge-coloring of \(G\) is called monochromatic disconnection coloring (or MD-coloring for short) if for any two vertices \(u\), \(v\) of \(G\) there exists a monochromatic edge set \(M\) such that \(u, v\) are in different components of \(G - M\). \textit{Y. Gao} and \textit{X. Li} [Bull. Malays. Math. Sci. Soc. (2) 45, No. 4, 1621--1640 (2022; Zbl 1496.05049)] introduce the concept monochromatic vertex disconnection coloring (or MVD-coloring for short) of \(G\): for any two vertices \(u\), \(v\) of \(G\), there is a monochromatic vertex set \(S\) such that \(u, v\) are in different components of \(G - S\) if \(u v \notin E (G)\), and if \(u v \in E (G)\), then \(u\) or \(v\) has the same color as \(S\) and \(u, v\) belong to distinct components of \((G - u v) - S\). \textit{M. Fu} and \textit{Y. Zhang} [AIMS Mathematics 2023, 8, No. 6, 13219--13240 (2023; \url{doi: 10.3934/math.2023668})] introduce another version of MVD-coloring by considering only nonadjacent vertices (in order to avoid confusion, we call the vertex-coloring a weak monochromatic vertex disconnection coloring, or WMVD-coloring for short). We use \(md (G)\) (resp. \(mvd (G), wmvd (G)\)) to denote the maximum number of colors that are used in an MD-coloring (resp. an MVD-coloring, a WMVD-coloring) of \(G\).
In this paper, we show that MVD-colorings and WMVD-colorings are equivalence in triangle-free graphs, and for any graph \(G\), we can obtain a triangle-free graph \(H\) in polynomial time such that \(mvd (G) = wmvd (H)\). We also show that there exist bijections between MD-colorings of \(L (G)\) (here, \(L (G)\) is the line graph of \(G)\), WMVD-colorings of \(G\) and MVD-colorings of \(G\) if \(G\) is a triangle-free graph without pendent edges, and show that for any graph \(G\), we can get a triangle-free graph \(H\) in polynomial time such that \(md (L(G)) = mvd (H) = wmvd (H)\). In addition, we give a complexity result on MD-colorings.Hardness transitions and uniqueness of acyclic colouringhttps://zbmath.org/1530.050552024-04-15T15:10:58.286558Z"M. A., Shalu"https://zbmath.org/authors/?q=ai:m-a.shalu"Antony, Cyriac"https://zbmath.org/authors/?q=ai:antony.cyriacSummary: For \(k \in \mathbb{N}\), a \(k\)-acyclic colouring of a graph \(G\) is a function \(f : V (G) \to \{0, 1, \dots, k - 1\}\) such that (i) \(f (u) \neq f (v)\) for every edge \(uv\) of \(G\), and (ii) there is no cycle in \(G\) bicoloured by \(f\). For \(k \in \mathbb{N}\), the problem \(k\)-Acyclic Colourability takes a graph \(G\) as input and asks whether \(G\) admits a \(k\)-acyclic colouring. \textit{P. Ochem} [in: 2005 European conference on combinatorics, graph theory and applications (EuroComb '05). Extended abstracts from the conference, Technische Universität Berlin, Berlin, Germany, September 5--9, 2005. Paris: Maison de l'Informatique et des Mathématiques Discrètes (MIMD). 357--362 (2005; Zbl 1192.05056)] proved that 3-Acyclic Colourability is NP-complete for bipartite graphs of maximum degree 4. \textit{D. Mondal} et al. [J. Discrete Algorithms 23, 42--53 (2013; Zbl 1334.05041)] proved that 4-Acyclic Colourability is NP-complete for graphs of maximum degree five. We prove that for \(k \geq 3\), \(k\)-Acyclic Colourability is NP-complete for bipartite graphs of maximum degree \(k + 1\), thereby generalising the NP-completeness result of Ochem [loc. cit.], and adding bipartiteness to the NP-completeness result of Mondal et al. [loc. cit.]. In contrast, \(k\)-Acyclic Colourability is polynomial-time solvable for graphs of maximum degree at most \(0.38 \, k^{3/4}\). Hence, for \(k \geq 3\), the least integer \(d\) such that \(k\)-Acyclic Colourability in graphs of maximum degree \(d\) is NP-complete, denoted by \(L_a^{(k)}\), satisfies \(0.38 \, k^{3/4} < L_a^{(k)} \leq k + 1\). We prove that for \(k \geq 4\), \(k\)-Acyclic Colourability in \(d\)-regular graphs is NP-complete if and only if \(L_a^{(k)} \leq d \leq 2k - 3\). We also show that it is coNP-hard to check whether an input graph \(G\) admits a unique \(k\)-acyclic colouring up to colour swaps (resp. up to colour swaps and automorphisms).Distance-layer structure of the de Bruijn and Kautz digraphs: analysis and application to deflection routinghttps://zbmath.org/1530.050632024-04-15T15:10:58.286558Z"Fàbrega, J."https://zbmath.org/authors/?q=ai:fabrega.josep"Martí-Farré, J."https://zbmath.org/authors/?q=ai:marti-farre.jaume"Muñoz, X."https://zbmath.org/authors/?q=ai:munoz.xavierSummary: In this article, we present a detailed study of the reach distance-layer structure of the De Bruijn and Kautz digraphs, and we apply our analysis to the performance evaluation of deflection routing in De Bruijn and Kautz networks. Concerning the distance-layer structure, we provide explicit polynomial expressions, in terms of the degree of the digraph, for the cardinalities of some relevant sets of this structure. Regarding the application to defection routing, and as a consequence of our polynomial description of the distance-layer structure, we formulate explicit expressions, in terms of the degree of the digraph, for some probabilities of interest in the analysis of this type of routing. De Bruijn and Kautz digraphs are fundamental examples of digraphs on alphabet and iterated line digraphs. If the topology of the network under consideration corresponds to a digraph of this type, we can perform, in principle, a similar vertex layer description.
{\copyright} 2023 The Authors. \textit{Networks} published by Wiley Periodicals LLC.The fully weighted toughness of a graphhttps://zbmath.org/1530.050732024-04-15T15:10:58.286558Z"Goddard, Wayne"https://zbmath.org/authors/?q=ai:goddard.wayne-d"VanLandingham, Julia"https://zbmath.org/authors/?q=ai:vanlandingham.juliaThis paper considers graphs with a weighting on the vertices. Throughout, the authors use that each weight is nonnegative and that the total weight is positive. Since a graph with connectivity 1 is not Hamiltonian, it follows that no value of the fully weighted toughness is sufficient to guarantee Hamiltonicity. But even if one imposes a large value of connectivity, there is no threshold. Graphs in the above family need not be 1-tough even for given connectivity but can have arbitrarily large fully weighted toughness.
The toughness of a graph \(G\) is defined to be the minimum value of \(|S|/k(G-S)\), where \(k(G-S)\) denotes the number of components of \(G-S\) and the minimum is taken over all cut-sets \(S\subseteq V(G)\). Here, the authors propose a version for weighted graphs that depends on the weights in both \(S\) and \(G-S\). Apart from considering bounds and basic properties, the paper is focused on the problem of assigning weights and maximizing the parameters.
The authors mean that it would be interesting to gain further insight into which graphs have \(\operatorname{MFWT}(G) = \tau(G)\) and which do not. Calculations and bounds for specific families of graphs would be helpful. For algorithmic questions, one can use similar ideas to those in [\textit{M. Shi} and \textit{Z. Wei}, J. Math. 2021, Article ID 6657594, 5 p. (2021; \url{doi:10.1155/2021/6657594})], to calculate fully weighted toughness for interval graphs; but are there other classes where calculating \(\tau w(G)\) is polynomial? One has no idea of the complexity of calculating \(\operatorname{MFWT}(G)\). This concept suggests that maybe one should investigate the weighted versions of other measures of the vulnerability of a graph.
The paper has interesting results and further problems.
Reviewer: V. Lokesha (Bangalore)On weighted graph separation problems and flow augmentationhttps://zbmath.org/1530.050742024-04-15T15:10:58.286558Z"Kim, Eun Jung"https://zbmath.org/authors/?q=ai:kim.eunjung|kim.eun-jung"Masařík, Tomáš"https://zbmath.org/authors/?q=ai:masarik.tomas"Pilipczuk, Marcin"https://zbmath.org/authors/?q=ai:pilipczuk.marcin-l"Sharma, Roohani"https://zbmath.org/authors/?q=ai:sharma.roohani"Wahlström, Magnus"https://zbmath.org/authors/?q=ai:wahlstrom.magnusSummary: One of the first applications of the recently introduced technique of flow augmentation [\textit{E. J. Kim} et al., in: Proceedings of the 54th annual ACM SIGACT symposium on theory of computing, STOC '22, Rome, Italy June 20--24, 2022. New York, NY: Association for Computing Machinery (ACM). 938--947 (2022; Zbl 07774390)] is a fixed-parameter algorithm for the weighted version of Directed Feedback Vertex Set, a landmark problem in parameterized complexity. In this article, we explore the applicability of flow augmentation to other weighted graph separation problems parameterized by the size of the cutset. We show the following:
\begin{itemize}
\item In weighted undirected graphs, Multicut is fixed-parameter tractable (FPT) in both the edge- and the vertex-deletion version.
\item The weighted version of Group Feedback Vertex Set is FPT, even with oracle access to group operations.
\item The weighted version of Directed Subset Feedback Vertex Set is FPT.
\end{itemize}
Our study reveals Directed Symmetric Multicut as the next important graph separation problem whose parameterized complexity remains unknown, even in the unweighted setting.Efficient enumeration of maximal split subgraphs and induced sub-cographs and related classeshttps://zbmath.org/1530.050872024-04-15T15:10:58.286558Z"Brosse, Caroline"https://zbmath.org/authors/?q=ai:brosse.caroline"Lagoutte, Aurélie"https://zbmath.org/authors/?q=ai:lagoutte.aurelie"Limouzy, Vincent"https://zbmath.org/authors/?q=ai:limouzy.vincent"Mary, Arnaud"https://zbmath.org/authors/?q=ai:mary.arnaud"Pastor, Lucas"https://zbmath.org/authors/?q=ai:pastor.lucasSummary: In this paper, we are interested in algorithms that take in input an arbitrary graph \(G\), and that enumerate in output all the (inclusion-wise) maximal ``subgraphs'' of \(G\) which fulfil a given property \(\varPi\). All over this paper, we study several different properties \(\varPi\), and the notion of subgraph under consideration (induced or not) will vary from a result to another.
More precisely, we present efficient algorithms to list all maximal split subgraphs, maximal induced cographs and maximal threshold graphs of a given input graph. All the algorithms presented here run in polynomial delay, and moreover for split graphs it only requires polynomial space. In order to develop an algorithm for maximal split (edge-)subgraphs, we establish a bijection between the maximal split subgraphs and the maximal stable sets of an auxiliary graph. For cographs and threshold graphs, the algorithms rely on a framework recently introduced by \textit{A. Conte} and \textit{T. Uno} [in: Proceedings of the 51st annual ACM SIGACT symposium on theory of computing, STOC '19, Phoenix, AZ, USA, June 23--26, 2019. New York, NY: Association for Computing Machinery (ACM). 1179--1190 (2019; Zbl 1433.68288)] called Proximity Search. Finally we consider the extension problem, which consists in deciding if there exists a maximal induced subgraph satisfying a property \(\varPi\) that contains a set of prescribed vertices and that avoids another set of vertices. We show that this problem is NP-complete for every non-trivial hereditary property \(\varPi\). We extend the hardness result to some specific edge version of the extension problem.Dynamic connectivity in disk graphshttps://zbmath.org/1530.051042024-04-15T15:10:58.286558Z"Baumann, Alexander"https://zbmath.org/authors/?q=ai:baumann.alexander"Kaplan, Haim"https://zbmath.org/authors/?q=ai:kaplan.haim"Klost, Katharina"https://zbmath.org/authors/?q=ai:klost.katharina"Knorr, Kristin"https://zbmath.org/authors/?q=ai:knorr.kristin"Mulzer, Wolfgang"https://zbmath.org/authors/?q=ai:mulzer.wolfgang-johann-heinrich"Roditty, Liam"https://zbmath.org/authors/?q=ai:roditty.liam"Seiferth, Paul"https://zbmath.org/authors/?q=ai:seiferth.paulSummary: Let \(S \subseteq \mathbb{R}^2\) be a set of \(n\) sites in the plane, so that every site \(s \in S\) has an associated radius \(r_s > 0\). Let \(\mathcal{D}(S)\) be the disk intersection graph defined by \(S\), i.e., the graph with vertex set \(S\) and an edge between two distinct sites \(s, t \in S\) if and only if the disks with centers \(s\), \(t\) and radii \(r_s\), \(r_t\) intersect. Our goal is to design data structures that maintain the connectivity structure of \(\mathcal{D}(S)\) as sites are inserted and/or deleted in \(S\). First, we consider unit disk graphs, i.e., we fix \(r_s = 1\), for all sites \(s \in S\). For this case, we describe a data structure that has \(O(\log^2 n)\) amortized update time and \(O(\log n/\log \log n)\) query time. Second, we look at disk graphs with bounded radius ratio \( \Psi \), i.e., for all \(s \in S\), we have \(1 \le r_s \le \Psi \), for a parameter \(\Psi\) that is known in advance. Here, we not only investigate the fully dynamic case, but also the incremental and the decremental scenario, where only insertions or only deletions of sites are allowed. In the fully dynamic case, we achieve amortized expected update time \(O(\Psi \log^4 n)\) and query time \(O(\log n/\log \log n)\). This improves the currently best update time by a factor of \(\Psi \). In the incremental case, we achieve logarithmic dependency on \(\Psi \), with a data structure that has \(O(\alpha (n))\) amortized query time and \(O(\log \Psi \log^4 n)\) amortized expected update time, where \(\alpha (n)\) denotes the inverse Ackermann function. For the decremental setting, we first develop an efficient decremental disk revealing data structure: given two sets \(R\) and \(B\) of disks in the plane, we can delete disks from \(B\), and upon each deletion, we receive a list of all disks in \(R\) that no longer intersect the union of \(B\). Using this data structure, we get decremental data structures with a query time of \(O(\log n/\log \log n)\) that supports deletions in \(O(n\log \Psi \log^4 n)\) overall expected time for disk graphs with bounded radius ratio \(\Psi\) and \(O(n\log^5 n)\) overall expected time for disk graphs with arbitrary radii, assuming that the deletion sequence is oblivious of the internal random choices of the data structures.Generalized cut trees for edge-connectivityhttps://zbmath.org/1530.051062024-04-15T15:10:58.286558Z"Lo, On-Hei Solomon"https://zbmath.org/authors/?q=ai:lo.on-hei-solomon"Schmidt, Jens M."https://zbmath.org/authors/?q=ai:schmidt.jens-mSummary: We present three cut trees of graphs, each of them giving insights into the edge-connectivity structure. All three cut trees have in common that they are defined with respect to a given binary symmetric relation \(R\) on the vertex set of the graph, which generalizes Gomory-Hu trees. Applying these cut trees, we prove the following:
\begin{itemize}
\item A pair of vertices \(\{v, w \}\) of a graph \(G\) is pendant if \(\lambda(v, w) = \min \{d(v), d(w) \}\). \textit{W. Mader} [Monatsh. Math. 78, 395--404 (1974; Zbl 0261.05121)] showed that every simple graph with minimum degree \(\delta\) contains at least \(\delta(\delta + 1) / 2\) pendant pairs. We improve this lower bound to \(\delta n / 24\) for every simple graph \(G\) on \(n\) vertices with \(\delta \geq 5\) or \(\lambda \geq 4\) or vertex connectivity \(\kappa \geq 3\), and show that this is optimal up to a constant factor with regard to every parameter.
\item Every simple graph \(G\) satisfying \(\delta > 0\) has \(O(n / \delta) \delta\)-edge-connected components. Moreover, every simple graph \(G\) that satisfies \(0 < \lambda < \delta\) has \(O((n / \delta)^2)\) cuts of size less than \(\min \{\frac{3}{2} \lambda, \delta \}\), and \(O((n / \delta)^{\lfloor 2 \alpha \rfloor})\) cuts of size at most \(\min \{\alpha \cdot \lambda, \delta - 1 \}\) for any given real number \(\alpha \geq 1\).
\item A cut is trivial if it or its complement in \(V(G)\) is a singleton. We provide an alternative proof of the following recent result of \textit{O.-H. S. Lo} et al. [Discrete Appl. Math. 303, 296--304 (2021; Zbl 1472.05085)]: Given a simple graph \(G\) on \(n\) vertices that satisfies \(\delta > 0\), we can compute vertex subsets of \(G\) in near-linear time such that contracting these vertex subsets separately preserves all non-trivial min-cuts of \(G\) and leaves a graph having \(O(n / \delta)\) vertices and \(O(n)\) edges.
\end{itemize}Restricted arc-connectivity of unidirectional star graphshttps://zbmath.org/1530.051072024-04-15T15:10:58.286558Z"Zhao, Xiaojun"https://zbmath.org/authors/?q=ai:zhao.xiaojun"Deng, Qingying"https://zbmath.org/authors/?q=ai:deng.qingying"Wang, Zhiyi"https://zbmath.org/authors/?q=ai:wang.zhiyiSummary: The restricted arc-connectivity is an effective assessment of the reliability of directed networks, which is an extended notion of arc-connectivity. Let \(D\) be a digraph. An arc set \(S\) of \(D\) is a restricted arc-cut of \(D\) if \(D - S\) has a strong connected component \(D^{^\prime}\) such that \(| V (D^{^\prime}) | \geq 2\) and \(D - V (D^{^\prime})\) contains an arc. The digraph \(D\) is called \(\lambda^{^\prime}\)-connected if there exists a restricted arc-cut in \(D\). The restricted arc-connectivity \(\lambda^{^\prime} (D)\) of a \(\lambda^{^\prime}\)-connected digraph \(D\) is the minimum cardinality over all restricted arc-cuts. We can get a unidirectional star graph by orienting the star graph with Day-Tripathi orientation. In this paper, we first show that the restricted arc-connectivity of the \(n\)-dimensional unidirectional star graph is \(n - 2\) when \(n\) is odd and \(n - 3\) when \(n\) is even for \(n \geq 4\). As a consequence, we prove that \(n\)-dimensional unidirectional star graph is super-\(\lambda\) when \(n \geq 3\) and \(n \neq 4\).Small vertex cover helps in fixed-parameter tractability of graph deletion problems over data streamshttps://zbmath.org/1530.051462024-04-15T15:10:58.286558Z"Bishnu, Arijit"https://zbmath.org/authors/?q=ai:bishnu.arijit"Ghosh, Arijit"https://zbmath.org/authors/?q=ai:ghosh.arijit"Kolay, Sudeshna"https://zbmath.org/authors/?q=ai:kolay.sudeshna"Mishra, Gopinath"https://zbmath.org/authors/?q=ai:mishra.gopinath"Saurabh, Saket"https://zbmath.org/authors/?q=ai:saurabh.saketSummary: In the study of parameterized streaming complexity on graph problems, the main goal is to design streaming algorithms for parameterized problems such that \(\mathcal{O}(f(k) \log^{\mathcal{O}(1)} n)\) space is enough, where \(f\) is an arbitrary computable function depending only on the parameter \(k\). However, in the past few years very few positive results have been established. Most of the graph problems that do have streaming algorithms of the above nature are ones where localized checking is required, like Vertex Cover or Maximum Matching parameterized by the size \(k\) of the solution we are seeking. \textit{R. Chitnis} et al. [SODA 2016, 1326--1344 (2016; Zbl 1409.68341)] have shown that many important parameterized problems that form the backbone of traditional parameterized complexity are known to require \(\Omega (n)\) bits of storage for any streaming algorithm; e.g. Feedback Vertex Set, Even Cycle Transversal, Odd Cycle Transversal, Triangle Deletion or the more general \(\mathcal{F}\)-Subgraph Deletion when parameterized by solution size \(k\). Our contribution lies in overcoming the obstacles to efficient parameterized streaming algorithms in graph deletion problems by utilizing the power of parameterization. We focus on the vertex cover size \(K\) as the parameter for the parameterized graph deletion problems we consider. In this work, we consider the four most well-studied streaming models: the Ea, Dea, Va (vertex arrival) and Al (adjacency list) models. Surprisingly, the consideration of vertex cover size \(K\) in the different models leads to a classification of positive and negative results for problems like \(\mathcal{F}\)-Subgraph Deletion and \(\mathcal{F}\)-Minor Deletion.Well-covered graphs with constraints on \(\Delta\) and \(\delta\)https://zbmath.org/1530.051522024-04-15T15:10:58.286558Z"Levit, Vadim E."https://zbmath.org/authors/?q=ai:levit.vadim-e"Tankus, David"https://zbmath.org/authors/?q=ai:tankus.davidSummary: A graph \(G\) is well-covered if all its maximal independent sets are of the same cardinality. Assume that a weight function \(w\) is defined on its vertices, while the weight of a set of vertices is the sum of their weights. Then \(G\) is \(w\)-well-covered if all maximal independent sets are of the same weight. For every graph \(G\), the set of weight functions \(w\) such that \(G\) is \(w\)-well-covered is a vector space, denoted \(WCW (G)\). In what follows, all weights are real. Let \(B\) be a complete bipartite induced subgraph of \(G\) on vertex sets of bipartition \(B_X\) and \(B_Y\). Then \(B\) is generating if there exists an independent set \(S\) such that \(S \cup B_X\) and \(S \cup B_Y\) are both maximal independent sets of \(G\). Generating subgraphs play an important role in finding \(WCW (G)\). In the restricted case that a generating subgraph \(B\) is isomorphic to \(K_{1,1}\), its unique edge is called a relating edge. Deciding whether an input graph \(G\) is well-covered is co-NP-complete. Therefore finding \(WCW (G)\) is co-NP-hard. Deciding whether an edge is relating is NP-complete. Therefore, deciding whether a subgraph is generating is NP-complete as well. This article deals with graphs \(G\) such that \(\Delta (G)=|V(G)|-k\) for some \(k\in \mathbb{N}\). We prove that for this family recognizing well-covered graphs is a polynomial problem, while finding \(WCW (G)\) is co-NP-hard. To the best of our knowledge, this is the first family of graphs in the literature known to have these properties. For this set of graphs, recognizing relating edges and generating subgraphs is NP-complete. The article also deals with connected graphs for which \(\delta (G) = k\) or \(\delta (G) \geq \frac{k-1}{k}|V(G)|\). For these families of graphs recognizing well-covered graphs is co-NP-complete, while recognizing relating edges is NP-complete.Dominoeshttps://zbmath.org/1530.051582024-04-15T15:10:58.286558Z"Kloks, T."https://zbmath.org/authors/?q=ai:kloks.ton"Kratsch, D."https://zbmath.org/authors/?q=ai:kratsch.dieter"Müller, H."https://zbmath.org/authors/?q=ai:muller.haikoSummary: A graph is called a domino if every vertex is contained in at most two maximal cliques. The class of dominoes properly contains the class of line graphs of bipartite graphs, and is in turn properly contained in the class of claw-free graphs. We give some characterizations of this class of graphs, show that they can be recognized in linear time, give a linear time algorithm for listing all maximal cliques (which implies a linear time algorithm computing a maximum clique of a domino) and show that the pathwidth problem remains NP-complete when restricted to the class of chordal dominoes.
For the entire collection see [Zbl 0813.68031].Implicit representation of relationshttps://zbmath.org/1530.051602024-04-15T15:10:58.286558Z"Glončák, Vladan"https://zbmath.org/authors/?q=ai:gloncak.vladan"Munkstrup, Jarl Emil Erla"https://zbmath.org/authors/?q=ai:munkstrup.jarl-emil-erla"Simonsen, Jakob Grue"https://zbmath.org/authors/?q=ai:simonsen.jakob-grueSummary: We consider implicit representation of an arbitrary family of relations on finite sets. We derive upper and lower bounds for the general cases and for a number of restricted subfamilies, in particular for sparse and symmetric relations, and for relations first-order definable from families for which labeling schemes are already known. Our work extends existing work on implicit representation of graphs in two ways: (i) the known upper and lower bounds for many standard families of graphs are special cases of the results we derive; (ii) we allow families of relations to relate elements on both distinct sets and on multiple copies of the same set, and for different relations in the same family to have different arities, and to be defined on distinct or overlapping sets. The present paper is the first to study bounds on the size of labeling schemes for relations (including graphs) defined from existing relations using basic operations such as first-order logic. The techniques used to prove new results in this setting may be of independent interest.Near-optimal dominating sets in dense random graphs in polynomial expected timehttps://zbmath.org/1530.051732024-04-15T15:10:58.286558Z"Nikoletseas, Sotiris E."https://zbmath.org/authors/?q=ai:nikoletseas.sotiris-e"Spirakis, Paul G."https://zbmath.org/authors/?q=ai:spirakis.paul-gSummary: The existence and efficient finding of small dominating sets in dense random graphs is examined in this work. We show, for the model \(G_{n,p}\) with \(p=1/2\), that:
\begin{itemize}
\item[1.] The probability of existence of dominating sets of size less than log \(n\) tends to zero as \(n\) tends to infinity.
\item[2.] Dominating sets of size \(\lceil \log n \rceil\) exist almost surely.
\item[3.] We provide two algorithms which construct small dominating sets in \(G_{n, 1/2}\) run in \(O (n \log n)\) time (on the average and also with high probability). Our algorithms almost surely construct a dominating set of size at most \((1+ \varepsilon) \log n\), for any fixed \(\varepsilon > 0\).
\end{itemize}
Our results extend to the case \(G_{n,p}\) with \(p\) fixed to any constant \(< 1\).
For the entire collection see [Zbl 0825.00128].Projective, sparse and learnable latent position network modelshttps://zbmath.org/1530.051762024-04-15T15:10:58.286558Z"Spencer, Neil A."https://zbmath.org/authors/?q=ai:spencer.neil-a"Shalizi, Cosma Rohilla"https://zbmath.org/authors/?q=ai:shalizi.cosma-rohillaSummary: When modeling network data using a latent position model, it is typical to assume that the nodes' positions are independently and identically distributed. However, this assumption implies the average node degree grows linearly with the number of nodes, which is inappropriate when the graph is thought to be sparse. We propose an alternative assumption -- that the latent positions are generated according to a Poisson point process -- and show that it is compatible with various levels of sparsity. Unlike other notions of sparse latent position models in the literature, our framework also defines a projective sequence of probability models, thus ensuring consistency of statistical inference across networks of different sizes. We establish conditions for consistent estimation of the latent positions, and compare our results to existing frameworks for modeling sparse networks.Average-case complexity of a branch-and-bound algorithm for \textsc{Min Dominating Set}https://zbmath.org/1530.051782024-04-15T15:10:58.286558Z"Denat, Tom"https://zbmath.org/authors/?q=ai:denat.tom"Harutyunyan, Ararat"https://zbmath.org/authors/?q=ai:harutyunyan.ararat"Melissinos, Nikolaos"https://zbmath.org/authors/?q=ai:melissinos.nikolaos"Paschos, Vangelis Th."https://zbmath.org/authors/?q=ai:paschos.vangelis-thSummary: The average-case complexity of a branch-and-bound algorithm for Min Dominating Set problem in random graphs in the \(\mathcal{G} (n, p)\) model is studied. We identify phase transitions between subexponential and exponential average-case complexities, depending on the growth of the probability \(p\) with respect to the number \(n\) of nodes.Towards a solution of the Holyer's problemhttps://zbmath.org/1530.051812024-04-15T15:10:58.286558Z"Lonc, Zbigniew"https://zbmath.org/authors/?q=ai:lonc.zbigniewSummary: Let \(H\) be a fixed graph. We say that a graph \(G\) admits an \(H\)-decomposition if the set of edges of \(G\) can be partitioned into subsets generating graphs isomorphic to \(H\). Denote by \(\mathcal{P}_H\) the problem of existence of an \(H\)-decomposition of a graph. The Holyer's problem is to classify the problems \(\mathcal{P}_H\) according to their computational complexities. In this paper we outline the proof of polynomiality of the problem \(\mathcal{P}_H\) for \(H\) being the union of \(s\) disjoint 2-edge paths. This case is believed to bear the main difficulties among so far uncovered cases.
For the entire collection see [Zbl 0825.00128].Deciding 3-colourability in less than \(O(1.415^n)\) stepshttps://zbmath.org/1530.051822024-04-15T15:10:58.286558Z"Schiermeyer, Ingo"https://zbmath.org/authors/?q=ai:schiermeyer.ingoSummary: In this paper we describe and analyze an improved algorithm for deciding the 3-colourability problem. If \(G\) is a simple graph on \(n\) vertices then we will show that this algorithm tests a graph for 3-colourability, i.e. an assignment of three colours to the vertices of \(G\) such that two adjacent vertices obtain different colours, in less than \(O(1.415^n)\) steps.
For the entire collection see [Zbl 0825.00128].Efficient algorithms for tripartitioning triconnected graphs and 3-edge-connected graphshttps://zbmath.org/1530.051832024-04-15T15:10:58.286558Z"Wada, Koichi"https://zbmath.org/authors/?q=ai:wada.koichi"Kawaguchi, Kimio"https://zbmath.org/authors/?q=ai:kawaguchi.kimioSummary: The extended \(k\)-partition problem is defined as follows. For the following inputs (1) an undirected graph \(G=(V, E)\) \((n = |V|, m= |E|)\), (2) a vertex subset \(V^\prime(\subseteq V)\), (3) distinct vertices \(a_i \in V^\prime(1 \leq i \leq k)\) and (4) natural numbers \(n_i\) \((1 \leq i \leq k)\) \((n_1 \leq \dots \leq n_k)\) such that \(n_1 +\dots + n_k =n^\prime = |V^\prime|\), we compute a partition \(V_1 \cup \dots \cup V_k\) of \(V\) and a partition \(V^\prime_1 \cup \dots V^\prime_k\) of \(V^\prime\) such that (a) each \(V^\prime_i\) is included in \(V_i\), (b) each \(V^\prime_i\) contains the specified vertex \(a_i\), (c) \(|V^\prime_i| = n_i\) and (d) each \(V_i\) induces a connected subgraph. If \(V^\prime = V\), then the problem is called the \(k\)-partition problem. In this paper, we show that if the input graph is triconnected the extended tripartition problem can be solved in \(O(m + (n - n_3) \cdot n)\) time and that the algorithm solves the original tripartition problem in \(O(m + (n_1 + n_2) \cdot n)\) time. Furthermore, we show that for a \(k\)-edge-connected graph \(G =(V, E)\) there exists a partition \(V_1 \cup \dots \cup V_k\) of \(V\) such that each \(V_i\) contains the specified vertex \(a_i\), \(|V_i| = n_i\) and \(k\) subgraphs \(G_1, \dots, G_k\) are mutually edge disjoint and each of \(G_i\) contains all of elements in \(V_i (1 \leq i \leq k)\) and the case in which \(k = 3\) can be solved in \(O(n^2)\) time.
For the entire collection see [Zbl 0825.00128].Weighted microscopic image reconstructionhttps://zbmath.org/1530.051842024-04-15T15:10:58.286558Z"Bar-Noy, Amotz"https://zbmath.org/authors/?q=ai:bar-noy.amotz"Böhnlein, Toni"https://zbmath.org/authors/?q=ai:bohnlein.toni"Lotker, Zvi"https://zbmath.org/authors/?q=ai:lotker.zvi"Peleg, David"https://zbmath.org/authors/?q=ai:peleg.david"Rawitz, Dror"https://zbmath.org/authors/?q=ai:rawitz.drorSummary: Assume we inspect a specimen represented as a collection of points and our task is to learn a physical value associated with each point. However, performing a direct measurement is impossible since it damages the specimen. The alternative is to employ aggregate measuring techniques (e.g., CT or MRI), whereby measurements are taken over subsets of points, and the exact values at each point are subsequently extracted by computational methods. In the Minimum Surgical Probing problem (MSP) the inspected specimen is represented by a graph \(G\) and a vector \(\ell \in \mathbb{R}^n\) that assigns a value \(\ell_i\) to each vertex \(i\). An aggregate measurement (called probe) centred at vertex \(i\) captures its entire neighbourhood, i.e., the outcome of a probe at \(i\) is \(\mathcal{P}_i = \sum_{j \in N (i) \cup \{i\}} \ell_j\) where \(N (i)\) is the open neighbourhood of vertex \(i\). \textit{A. Bar-Noy} et al. [Lect. Notes Comput. Sci. 12607, 373--386 (2021; Zbl 1490.68270)] gave a criterion whether the vector \(\ell\) can be recovered from the collection of probes \(\mathcal{P} = \{\mathcal{P}_v \mid v \in V (G)\}\) alone. However, there are graphs where the vector \(\ell\) cannot be recovered from \(\mathcal{P}\) alone. In these cases, we are allowed to use surgical probes. A surgical probe at vertex \(i\) returns \(\ell_i\). The objective of MSP is to recover \(\ell\) from \(\mathcal{P}\) and \(G\) using as few surgical probes as possible.
In this paper, we introduce the Weighted Minimum Surgical Probing (WMSP) problem in which a vertex \(i\) may have an aggregation coefficient \(w_i\), namely \(\mathcal{P}_i = \sum_{j \in N (i)} \ell_j + w_i \ell_i\). We show that WMSP can be solved in polynomial time. Moreover, we analyse the number of required surgical probes depending on the weight vector \(w\). For any graph, we give two boundaries outside of which no surgical probes are needed to recover the vector \(\ell\). The boundaries are connected to the (Signless) Laplacian matrix.
In addition, we consider the special case where \(w = \vec{0}\) and explore the range of possible behaviour of WMSP by determining the number of surgical probes necessary in certain graph families, such as trees and various grid graphs.\(s\)-club cluster vertex deletion on interval and well-partitioned chordal graphshttps://zbmath.org/1530.051852024-04-15T15:10:58.286558Z"Chakraborty, Dibyayan"https://zbmath.org/authors/?q=ai:chakraborty.dibyayan"Chandran, L. Sunil"https://zbmath.org/authors/?q=ai:chandran.l-sunil"Padinhatteeri, Sajith"https://zbmath.org/authors/?q=ai:padinhatteeri.sajith"Pillai, Raji R."https://zbmath.org/authors/?q=ai:pillai.raji-rSummary: In this paper, we study the computational complexity of \(s\)-Club Cluster Vertex Deletion. Given a graph, \(s\)-Club Cluster Vertex Deletion (s-CVD) aims to delete the minimum number of vertices from the graph so that each connected component of the resulting graph has a diameter at most \(s\). When \(s = 1\), the corresponding problem is popularly known as Cluster Vertex Deletion (CVD). We provide a faster algorithm for \(s\)-CVD on interval graphs. For each \(s \geq 1\), we give an \(O (n (n + m))\)-time algorithm for \(s\)-CVD on interval graphs with \(n\) vertices and \(m\) edges. In the case of \(s = 1\), our algorithm is a slight improvement over the \(O (n^3)\)-time algorithm of \textit{Y. Cao} et al. [Theor. Comput. Sci. 745, 75--86 (2018; Zbl 1401.68114)], and for \(s \geq 2\), it significantly improves the state-of-the-art running time \(\big(O \big(n^4\big)\big)\).
We also give a polynomial-time algorithm to solve CVD on well-partitioned chordal graphs, a graph class introduced by \textit{J. Ahn} et al. [Discrete Math. 345, No. 10, Article ID 112985, 23 p. (2022; Zbl 1491.05146)] as a tool for narrowing down complexity gaps for problems that are hard on chordal graphs, and easy on split graphs. Our algorithm relies on a characterisation of the optimal solution and on solving polynomially many instances of the Weighted Bipartite Vertex Cover. This generalises a result of Cao et al. [loc. cit.] on split graphs. We also show that for any even integer \(s \geq 2\), \(s\)-CVD is NP-hard on well-partitioned chordal graphs.A quasi-ergodic approach to non-integer base expansionshttps://zbmath.org/1530.110102024-04-15T15:10:58.286558Z"Komornik, Vilmos"https://zbmath.org/authors/?q=ai:komornik.vilmos"Loreti, Paola"https://zbmath.org/authors/?q=ai:loreti.paola"Pedicini, Marco"https://zbmath.org/authors/?q=ai:pedicini.marcoAuthors' abstract: P. Erdős et al. proved in 1990 that every nontrivial number has a continuum of expansions on two-letter alphabets in every base smaller than the Golden ratio, and that this property fails for the Golden ratio base. It was shown in a recent paper of Baiocchi et al. that if we replace the powers of the Golden ratio by the closely related Fibonacci sequence, then the resulting integer base expansions still have the continuum expansion property. The proof heavily relied on the special properties of the Golden ratio. The difficulty came from the fact that the new expansions do not have any more the ergodic structure of non-integer base expansions. In this paper we introduce a new ``quasi-ergodic'' approach that allows us to handle many more general cases. We apply this approach to Baker's generalized Golden ratios.
Reviewer: Michel Rigo (Liège)Combinatorial approach of unified Apostol-type polynomials using \(\alpha \)-distanced wordshttps://zbmath.org/1530.110302024-04-15T15:10:58.286558Z"Bényi, Beáta"https://zbmath.org/authors/?q=ai:benyi.beata"Nkonkobe, Sithembele"https://zbmath.org/authors/?q=ai:nkonkobe.sithembeleThe aim of this paper is to introduce a generalization of the unified Apostol-Fubini polynomials of higher order and obtain identities using combinatorial methods. Given two positive integers \(k\) and \(\alpha\), let \(\beta=b\cdot \alpha\) and \(\gamma=c\cdot \alpha\) be integer multiples of \(\alpha\). The authors consider an alphabet containing \(k\beta+\gamma\) letters. So the alphabet can be represented as a set of \(k\beta\) symbols
\[
\bigcup_{i=1}^k \{1_{i,1},\ldots,1_{i,\alpha},2_{i,1},\ldots,2_{i,\alpha},\ldots,b_{i,1},\ldots,b_{i,\alpha}\}
\]
and a set of \(\gamma\) extra symbols
\[
\{1'_1,\ldots,1'_\alpha,2'_1,\ldots,2'_\alpha,\ldots,c'_1,\ldots,c'_\alpha\}.
\]
Where we use two indices, the authors consider \(k\) different sizes and \(\alpha\) possible accents for each of the first \(b\) symbols. For the last \(\gamma\) symbols, the authors only consider accents (so a unique size). Since there are there are \(\alpha\)-similar variants of each symbol, the authors introduce the notion of \(\alpha\)-distanced words. They consider the set of weighted \(\alpha\)-distanced words and show some of their properties. The paper ends with applications to generalized Stirling numbers and related number sequences, higher-order generalized geometric polynomials defined by \textit{L. Kargin} and \textit{B. Çekim} [Turk. J. Math. 42, No. 3, 887--903 (2018; Zbl 1424.11059)].
Reviewer: Michel Rigo (Liège)Generic Gröbner basis of a parametric ideal and its application to a comprehensive Gröbner systemhttps://zbmath.org/1530.130452024-04-15T15:10:58.286558Z"Nabeshima, Katsusuke"https://zbmath.org/authors/?q=ai:nabeshima.katsusukeIn this paper, the properties of generic Gröbner bases for parametric polynomial ideals and their application in the construction of comprehensive Gröbner systems are discussed. Let \(t = \{t_1,\ldots, t_m\}\) be a set of parameters and \(x = \{x_1,\ldots, x_n\}\) a set of variables. Moreover, let \(K\) be a field of characteristic zero. Finally, let \(F\subset K[t][x]\) be a set of parametric polynomials. The aim of this paper is to find a parametric Gröbner basis for the ideal generated by \(F\).
For this purpose, the author first computes a generic Gröbner basis \(G\) for \(F\) as ideal in \(K(t)[x]\). Then, from the set \(G\) a branch of the comprehensive Gröbner system of \(\langle F \rangle\) is produced. This means a set of null and not-null conditions such that for each \(m\)-tuple \(\sigma=(\sigma_1,\ldots ,\sigma_m)\in K^m\) satisfying the conditions, \(G_\sigma\) becomes a Gröbner basis for \(\langle F\rangle\) in \(K[x]\). The construction of a full comprehensive Gröbner basis continues by creating other branches. An algorithm based on this discussion has been implemented in the computer algebra system Risa/Asir and compared with the Kapur-Sun-Wang algorithm. The results show that the new algorithm performs better on some of the examples.
Reviewer: Amir Hashemi (Isfahan)Real circles tangent to 3 conicshttps://zbmath.org/1530.141032024-04-15T15:10:58.286558Z"Breiding, P."https://zbmath.org/authors/?q=ai:breiding.paul"Lindberg, J."https://zbmath.org/authors/?q=ai:lindberg.julia"Ong, W. J. G."https://zbmath.org/authors/?q=ai:ong.wern-juin-gabriel"Sommer, L."https://zbmath.org/authors/?q=ai:sommer.luise|sommer.lieselThe main result of this article shows that there are exactly 184 circles tangent to three general conics. An example of three real conics with 136 tangent real circles is provided, and it is conjectured that indeed 136 is the upper bound on the number of real circles tangent to three conics. The second part of the article deals with machine learning algorithms finding examples of three conics with many real tangent circle and predicting the number of real circles tangent to three given real conics.
Reviewer: Hanieh Keneshlou (Leipzig)Algorithmic study of superspecial hyperelliptic curves over finite fieldshttps://zbmath.org/1530.141042024-04-15T15:10:58.286558Z"Kudo, Momonari"https://zbmath.org/authors/?q=ai:kudo.momonari"Harashita, Sushi"https://zbmath.org/authors/?q=ai:harashita.sushiThis paper is a full version of the conference paper [\textit{M. Kudo} and \textit{S. Harashita}, Lect. Notes Comput. Sci. 11321, 58--73 (2018; Zbl 1446.11120)]. The paper studies the question of enumerating superspecial hyperelliptic curves of genus \(g\) over a finite field with \(q > 2g+1\) elements. The curves are counted in two ways: by \(\mathbb{F}_q\)-isomorphism classes and by \(\overline{\mathbb{F}_q}\)-isomorphism classes. The enumeration has been implemented and carried out for some small \(q\) and \(g\) and applications to maximal and minimal hyperelliptic curves are discussed.
The algorithm uses the Cartier-Manin matrix of a hyperelliptic curve to give algebraic conditions in terms of its coefficients to detect whether the curve is superspecial. These equations are reduced so that a Gröbner basis computation can be used to find all the solutions. Then isomorphism testing is used to remove curves that have been counted multiple times.
The paper also discusses an algorithm to compute the automorphism group and geometric automorphism group of hyperelliptic curves, and how these can be used in combination with Galois cohomology to determine the number of \(\mathbb{F}_q\)-forms of a given curve over \(\overline{\mathbb{F}_q}\). As an application the authors compute the automorphism groups for the superspecial curves that they enumerated.
Reviewer: Raymond van Bommel (Cambridge, MA)Automated discovery of angle theoremshttps://zbmath.org/1530.150252024-04-15T15:10:58.286558Z"Todd, Philip"https://zbmath.org/authors/?q=ai:todd.philip-hSummary: We consider geometry theorems whose premises and statement comprise a set of bisector conditions. Each premise and the statement can be represented as the rows of a ``bisector matrix'': one with three non zero elements per row, one element with value \(-2\) and the others with value 1. The existence of a theorem corresponds to rank deficiency in this matrix. Our method of theorem discovery starts with identification of rank deficient bisector matrices. Some such matrices can be represented as graphs whose vertices correspond to matrix rows and whose edges correspond to matrix columns. We show that if a bisector matrix which can be represented as a graph is rank deficient, then the graph is bicubic. We give an algorithm for finding the rank deficient matrices for a Hamiltonian bicubic graph, and report on the results for graphs with 6, 8, 10 and 12 vertices. We discuss a method of deriving rank deficient bisector matrices with more than 2 non-zero elements. We extend the work to matrices containing rows corresponding to angle trisectors.Semi-tensor product of quaternion matrices and its applicationhttps://zbmath.org/1530.150262024-04-15T15:10:58.286558Z"Fan, Xueling"https://zbmath.org/authors/?q=ai:fan.xueling"Li, Ying"https://zbmath.org/authors/?q=ai:li.ying.1"Ding, Wenxv"https://zbmath.org/authors/?q=ai:ding.wenxv"Zhao, Jianli"https://zbmath.org/authors/?q=ai:zhao.jianli(no abstract)Generalized iterated-sums signatureshttps://zbmath.org/1530.160332024-04-15T15:10:58.286558Z"Diehl, Joscha"https://zbmath.org/authors/?q=ai:diehl.joscha"Ebrahimi-Fard, Kurusch"https://zbmath.org/authors/?q=ai:ebrahimi-fard.kurusch"Tapia, Nikolas"https://zbmath.org/authors/?q=ai:tapia.nikolasUnlike iterated-integrals and iterated-sum signatures, Kiraly and Oberhauser's generalization of signatures (introduced in a specific context) are not compatible with the shuffle product, nor the quasishuffle product. In order to recover a character property for them, the quasishuffle product is deformed by coalgebra isomorphisms, and especially a family of isomorphism indexed by formal diffeomorphisms. These products are shown to be compatible with a generalized iterated-sum signature defined with the same formal diffeomorphism.
In a second part, inspired by machine learning applications, it is shown that polynomial transformations of the time series increments induce transformation of iterated-sum signatures dually corresponding to a quasishuffle and Hopf algebra endomorphism, whereas polynomial transformations of the time series itself induce transformation of iterated-sum signatures dually corresponding to a quasishuffle, but not Hopf algebra, endomorphism.
Reviewer: Loïc Foissy (Calais)Situated transition systemshttps://zbmath.org/1530.180232024-04-15T15:10:58.286558Z"Nester, Chad"https://zbmath.org/authors/?q=ai:nester.chadSummary: We construct a monoidal category of open transition systems that generate material history as transitions unfold, which we call situated transition systems. The material history generated by a composite system is composed of the material history generated by each component. The construction is parameterized by a symmetric strict monoidal category, understood as a resource theory, from which material histories are drawn. We pay special attention to the case in which this category is compact closed. In particular, if we begin with a compact closed category of integers then the resulting situated transition systems can be understood as systems of double-entry bookkeeping accounts.
For the entire collection see [Zbl 1522.68034].Algorithms for experimenting with Zariski dense subgroupshttps://zbmath.org/1530.200032024-04-15T15:10:58.286558Z"Detinko, Alla S."https://zbmath.org/authors/?q=ai:detinko.alla-s"Flannery, Dane Laurence"https://zbmath.org/authors/?q=ai:flannery.dane-l"Hulpke, Alexander Jörg"https://zbmath.org/authors/?q=ai:hulpke.alexanderSummary: We give a method to describe all congruence images of a finitely generated Zariski dense group \(H \leq \operatorname{SL} (n, \mathbb Z)\). The method is applied to obtain efficient algorithms for solving this problem in odd prime degree \(n\); if \(n = 2\) then we compute all congruence images only modulo primes. We propose a separate method that works for all \(n\) as long as \(H\) contains a known transvection. The algorithms have been implemented in GAP, enabling computer experiments with important classes of linear groups that have recently emerged.The conjugacy problem for Higman's grouphttps://zbmath.org/1530.200942024-04-15T15:10:58.286558Z"Baker, Owen"https://zbmath.org/authors/?q=ai:baker.owenSummary: Higman's group \(H=\langle a,b,c,d\mid b^a= b^2, c^b= c^2, d^c= d^2, a^d= a^2\rangle\) is a remarkable group with large (non-elementary) Dehn function. \textit{G. Higman} [J. Lond. Math. Soc. 26, 61--64 (1951; Zbl 0042.02201)] constructed the group in 1951 to produce the first examples of infinite simple groups. Using finite state automata, and studying fixed points of certain \textit{finite state transducers}, we show the conjugacy problem in \(H\) is decidable for all inputs. \textit{V. Diekert} et al. [Int. J. Algebra Comput. 22, No. 8, Paper No. 1240008, 19 p. (2012; Zbl 1264.20034)] have recently shown the word problem in \(H\) is solvable in polynomial time, using the \textit{power circuit} technology of \textit{A. G. Miasnikov} et al. [Int. J. Algebra Comput. 22, No. 6, 1250047, 51 p. (2012; Zbl 1285.03052)]. Building on this work, we also show in a strongly generic setting that the conjugacy problem for \(H\) has a polynomial time solution.Some properties of affine \({\mathcal{C}}\)-semigroupshttps://zbmath.org/1530.201862024-04-15T15:10:58.286558Z"García-García, J. I."https://zbmath.org/authors/?q=ai:garcia-garcia.juan-ignacio"Marín-Aragón, D."https://zbmath.org/authors/?q=ai:marin-aragon.daniel"Sánchez-Loureiro, A."https://zbmath.org/authors/?q=ai:sanchez-loureiro.a"Vigneron-Tenorio, A."https://zbmath.org/authors/?q=ai:vigneron-tenorio.albertoSummary: Numerical semigroups have been extensively studied throughout the literature, and many of their invariants have been characterized. In this work, we generalize some of the most important results about symmetry, pseudo-symmetry, or fundamental gaps, to affine \({\mathcal{C}}\)-semigroups. In addition, we give algorithms to compute the tree of irreducible \({\mathcal{C}}\)-semigroups and \({\mathcal{C}}\)-semigroups with a given Frobenius vector.Inflation of poorly conditioned zeros of systems of analytic functionshttps://zbmath.org/1530.320072024-04-15T15:10:58.286558Z"Burr, Michael"https://zbmath.org/authors/?q=ai:burr.michael-a"Leykin, Anton"https://zbmath.org/authors/?q=ai:leykin.antonSummary: Given a system of analytic functions and an approximate zero, we introduce inflation to transform this system into one with a regular quadratic zero. This leads to a method for isolating a cluster of zeros of the given system.Stability analysis based on Caputo-type fractional-order quantum neural networkshttps://zbmath.org/1530.340602024-04-15T15:10:58.286558Z"Dong, Yumin"https://zbmath.org/authors/?q=ai:dong.yumin"Li, Xiang"https://zbmath.org/authors/?q=ai:li.xiang.11"Liao, Wei"https://zbmath.org/authors/?q=ai:liao.wei"Hou, Dong"https://zbmath.org/authors/?q=ai:hou.dongSummary: In this paper, a quantum neural network with multilayer activation function is proposed by using multilayer Sigmoid function superposition and learning algorithm to adjust quantum interval. On this basis, the quasiuniform stability of fractional quantum neural networks with mixed delays is studied. According to the order of two different cases, the conditions of quasi uniform stability of networks are given by using the techniques of linear matrix inequality analysis, and the sufficiency of the conditions is proved. Finally, the feasibility of the conclusion is verified by experiments.Hamilton-Jacobi scaling limits of Pareto peeling in 2Dhttps://zbmath.org/1530.351102024-04-15T15:10:58.286558Z"Bou-Rabee, Ahmed"https://zbmath.org/authors/?q=ai:bou-rabee.ahmed"Morfe, Peter S."https://zbmath.org/authors/?q=ai:morfe.peter-sSummary: Pareto hull peeling is a discrete algorithm, generalizing convex hull peeling, for sorting points in Euclidean space. We prove that Pareto peeling of a random point set in two dimensions has a scaling limit described by a first-order Hamilton-Jacobi equation and give an explicit formula for the limiting Hamiltonian, which is both non-coercive and non-convex. This contrasts with convex peeling, which converges to curvature flow. The proof involves direct geometric manipulations in the same spirit as [\textit{J. Calder}, Nonlinear Anal., Theory Methods Appl., Ser. A, Theory Methods 141, 88--108 (2016; Zbl 1347.35080)].Lump, breather and interaction solutions to the (3+1)-dimensional generalized Camassa-Holm Kadomtsev-Petviashvili equationhttps://zbmath.org/1530.352102024-04-15T15:10:58.286558Z"Chen, Wenxia"https://zbmath.org/authors/?q=ai:chen.wenxia"Tang, Liangping"https://zbmath.org/authors/?q=ai:tang.liangping"Tian, Lixin"https://zbmath.org/authors/?q=ai:tian.lixinSummary: This paper analyzes the (3+1)-dimensional generalized Camassa-Holm Kadomtsev-Petviashvili(gCH-KP) equation, which has recently gained popularity in ocean physics and hydrodynamics engineering. Based on the Hirota bilinear method and symbolic computation, we explore the lump solution, breather solution and new interaction solutions. The maximum and minimum value of the lump solution are obtained by theoretical calculation. Dynamic characteristics of these solutions are depicted by presenting some three dimensional, two dimensional plots and density plots.Control of neural transport for normalising flowshttps://zbmath.org/1530.352472024-04-15T15:10:58.286558Z"Ruiz-Balet, Domènec"https://zbmath.org/authors/?q=ai:ruiz-balet.domenec"Zuazua, Enrique"https://zbmath.org/authors/?q=ai:zuazua.enriqueSummary: Inspired by normalising flows, we analyse the bilinear control of neural transport equations by means of time-dependent velocity fields restricted to fulfil, at any time instance, a simple neural network ansatz. The \(L^1\) approximate controllability property is proved, showing that any probability density can be driven arbitrarily close to any other one in any time horizon. The control vector fields are built explicitly and inductively and this provides quantitative estimates on their complexity and amplitude. This also leads to statistical error bounds when only random samples of the target probability density are available.Less emphasis on hard regions: curriculum learning of PINNs for singularly perturbed convection-diffusion-reaction problemshttps://zbmath.org/1530.352982024-04-15T15:10:58.286558Z"Wang, Yufeng"https://zbmath.org/authors/?q=ai:wang.yufeng"Xu, Cong"https://zbmath.org/authors/?q=ai:xu.cong"Yang, Min"https://zbmath.org/authors/?q=ai:yang.min"Zhang, Jin"https://zbmath.org/authors/?q=ai:zhang.jin.10|zhang.jin.1Summary: Although physics-informed neural networks (PINNs) have been successfully applied in a wide variety of science and engineering fields, they can fail to accurately predict the underlying solution in slightly challenging convection-diffusion-reaction problems. In this paper, we investigate the reason of this failure from a domain distribution perspective, and identify that learning multi-scale fields simultaneously makes the network unable to advance its training and easily get stuck in poor local minima. We show that the widespread experience of sampling more collocation points in high-loss regions hardly help optimize and may even worsen the results. These findings motivate the development of a novel curriculum learning method that encourages neural networks to prioritize learning on easier non-layer regions while downplaying learning on harder regions. The proposed method helps PINNs automatically adjust the learning emphasis and thereby facilitates the optimization procedure. Numerical results on typical benchmark equations show that the proposed curriculum learning approach mitigates the failure modes of PINNs and can produce accurate results for very sharp boundary and interior layers. Our work reveals that for equations whose solutions have large scale differences, paying less attention to high-loss regions can be an effective strategy for learning them accurately.On periodic decompositions, one-sided nonexpansive directions and Nivat's conjecturehttps://zbmath.org/1530.370192024-04-15T15:10:58.286558Z"Colle, Cleber Fernando"https://zbmath.org/authors/?q=ai:colle.cleber-fernandoSummary: Nivat's conjecture is a famous open problem in symbolic dynamics. Recent advances toward a proof for Nivat's conjecture involve a precise control of nonexpansive lines and one-sided nonexpansive directions. In his Ph.D. thesis, \textit{M. Szabados} [An Algebraic Approach to Nivat's Conjecture, Ph.D. thesis, University of Turku, 2018] showed that every low pattern complexity configuration can be decomposed into a finite sum of periodic configurations. If we consider a not fully periodic configuration with a minimal periodic decomposition, that is, a periodic decomposition with the smallest possible number of periodic configurations, a nonexpansive line contains a period of some periodic configuration in such minimal periodic decomposition. Michal Szabados conjectured that the converse also holds. In this paper, we provide conditions where (i) Szabados's conjecture holds and (ii) a given line is a nonexpansive line if and only if the same line endowed with a given orientation is a one-sided nonexpansive direction. As an application of our main result, we get that Nivat's conjecture holds if and only if it holds for configurations satisfying (i) and (ii).Independent finite automata on Cayley graphshttps://zbmath.org/1530.370252024-04-15T15:10:58.286558Z"Salo, Ville"https://zbmath.org/authors/?q=ai:salo.ville-o"Törmä, Ilkka"https://zbmath.org/authors/?q=ai:torma.ilkka-aSummary: In the setting of symbolic dynamics on discrete finitely generated infinite groups, we define a model of finite automata with multiple independent heads that walk on Cayley graphs, called group-walking automata, and use it to define subshifts. We characterize the torsion groups (also known as periodic groups) as those on which the group-walking automata are strictly weaker than Turing machines, and those on which the head hierarchy is infinite.Reversible causal graph dynamics: invertibility, block representation, vertex-preservationhttps://zbmath.org/1530.370272024-04-15T15:10:58.286558Z"Arrighi, P."https://zbmath.org/authors/?q=ai:arrighi.pablo"Martiel, S."https://zbmath.org/authors/?q=ai:martiel.simon"Perdrix, S."https://zbmath.org/authors/?q=ai:perdrix.simonSummary: Causal Graph Dynamics extend Cellular Automata to arbitrary time-varying graphs of bounded degree. The whole graph evolves in discrete time steps, and this global evolution is required to have a number of symmetries: shift-invariance (it acts everywhere the same) and causality (information has a bounded speed of propagation). We add a further physics-like symmetry, namely reversibility. In particular, we extend two fundamental results on reversible cellular automata, by proving that the inverse of a causal graph dynamics is a causal graph dynamics, and that these reversible causal graph dynamics can be represented as finite-depth circuits of local reversible gates. We also show that reversible causal graph dynamics preserve the size of all but a finite number of graphs.A tutorial on elementary cellular automata with fully asynchronous updating. General properties and convergence dynamicshttps://zbmath.org/1530.370292024-04-15T15:10:58.286558Z"Fatès, Nazim"https://zbmath.org/authors/?q=ai:fates.nazim-aSummary: We present a panorama of the convergence properties of the 256 Elementary Cellular Automata under fully asynchronous updating, that is, when only one cell is updated at each time step. We regroup here various results which have been presented in different articles and expose a full analysis of the behaviour of finite systems with periodic boundary conditions. Our classification relies on the scaling properties of the average convergence time to a fixed point. We observe that different scaling laws can be found, which fall in one of the following classes: logarithmic, linear, quadratic, exponential and non-converging. The techniques for quantifying this behaviour rely mainly on Markov chain theory and martingales. Most behaviours can be studied analytically but there are still many rules for which obtaining a formal characterisation of their convergence properties is still an open problem.The impact of alphabet size on pattern complexity of maxmin-\( \omega\) cellular automatahttps://zbmath.org/1530.370312024-04-15T15:10:58.286558Z"Patel, Ebrahim L."https://zbmath.org/authors/?q=ai:patel.ebrahim-lSummary: We present an analysis of an additive cellular automaton (CA) under asynchronous dynamics. The asynchronous scheme is maxmin-\( \omega \), a deterministic system, introduced in our previous work with a binary alphabet. Extending this work, we study the impact of a larger alphabet, which also allows a meaningful inference of the behaviour of the resultant CA from the asymptotic behaviour of the maxmin-\( \omega\) update system. Far from being a straightforward positive correlation between complexity and alphabet size, we show that there is a region of \(\omega\) and alphabet size where complexity of CA is maximal. Thus, despite employing a fixed CA rule, the complexity of this CA can be controlled by \(\omega\) and alphabet size. The main message is that the effect of maxmin-\( \omega\) updating on the state of a network can be well understood, especially if the state alphabet is counter-intuitively large.Controlling mean exit time of stochastic dynamical systems based on quasipotential and machine learninghttps://zbmath.org/1530.371062024-04-15T15:10:58.286558Z"Li, Yang"https://zbmath.org/authors/?q=ai:li.yang.8"Yuan, Shenglan"https://zbmath.org/authors/?q=ai:yuan.shenglan"Xu, Shengyuan"https://zbmath.org/authors/?q=ai:xu.shengyuanSummary: The mean exit time escaping basin of attraction in the presence of white noise is of practical importance in various scientific fields. In this work, we propose a strategy to control mean exit time of general stochastic dynamical systems to achieve a desired value based on the quasipotential concept and machine learning. Specifically, we develop a neural network architecture to compute the global quasipotential function. Then we design a systematic iterated numerical algorithm to calculate the controller for a given mean exit time. Moreover, we identify the most probable path between metastable attractors with the help of the effective Hamilton-Jacobi scheme and the trained neural network. Numerical experiments with various dimensions and structures demonstrate that our control strategy is effective and sufficiently accurate.Stability analysis of a bacterial growth model through computer algebrahttps://zbmath.org/1530.371112024-04-15T15:10:58.286558Z"Yabo, Agustín G."https://zbmath.org/authors/?q=ai:yabo.agustin-gabriel"Safey El Din, Mohab"https://zbmath.org/authors/?q=ai:safey-el-din.mohab"Caillau, Jean-Baptiste"https://zbmath.org/authors/?q=ai:caillau.jean-baptiste"Gouzé, Jean-Luc"https://zbmath.org/authors/?q=ai:gouze.jean-lucSummary: We describe microbial growth and production of value-added chemical compounds in a continuous bioreactor through a dynamical system and we study the local stability of the equilibrium of interest by means of the classical Routh-Hurwitz criterion. The mathematical model considers various biological and structural parameters related to the bioprocess (concentration of substrate inflow, constants of the microchemical reactions, steady-state mass fractions of intracellular proteins, etc.) and thus, the stability condition is given in terms of these parameters. This boils down to deciding the consistency of a system of polynomial inequalities over the reals, which is challenging to solve from an analytical perspective, and out of reach even for traditional computational software designed to solve such problems. We show how to adapt classical techniques for solving polynomial systems to cope with this problem within a few minutes by leveraging its structural properties, thus completing the stability analysis of our model. The paper is accompanied by a Maple worksheet available online.Greedy approximation algorithms for sparse collectionshttps://zbmath.org/1530.420332024-04-15T15:10:58.286558Z"Rey, Guillermo"https://zbmath.org/authors/?q=ai:rey.guillermoSummary: We describe a greedy algorithm that approximates the Carleson constant of a collection of general sets. The approximation has a logarithmic loss in a general setting, but is optimal up to a constant with only mild geometric assumptions. The constructive nature of the algorithm gives additional information about the almost disjoint structure of sparse collections.
As applications, we give three results for collections of axis-parallel rectangles in every dimension. The first is a constructive proof of the equivalence between Carleson and sparse collections, first shown by \textit{T. S. Hänninen} [Ark. Mat. 56, No. 2, 333--339 (2018; Zbl 1406.42028)]. The second is a structure theorem proving that every finite collection \(\mathcal{E}\) can be partitioned into \(\mathcal{O}(N)\) sparse subfamilies, where \(N\) is the Carleson constant of \(\mathcal{E}\). We also give examples showing that such a decomposition is impossible when the geometric assumptions are dropped. The third application is a characterization of the Carleson constant involving only \(L^{1,\infty}\) estimates.Forecasting stock return volatility using the realized GARCH model and an artificial neural networkhttps://zbmath.org/1530.620312024-04-15T15:10:58.286558Z"Bakkali, Youssra"https://zbmath.org/authors/?q=ai:bakkali.youssra"El Merzguioui, Mhamed"https://zbmath.org/authors/?q=ai:el-merzguioui.mhamed"Akharif, Abdelhadi"https://zbmath.org/authors/?q=ai:akharif.abdelhadi"Azmani, Abdellah"https://zbmath.org/authors/?q=ai:azmani.abdellahSummary: Volatility forecasting is required for risk management, asset allocation, option pricing, and financial market trading. It can be done by using various time series forecasting techniques and Artificial Neural Networks (ANN).
The current research focuses on the modeling and forecasting of stock market indices using high-frequency data. A recent high-frequency volatility model is called the Realized GARCH (RGARCH) model, where the key feature is an equation that relates the realized measure to the conditional variance of returns. This equation incorporates an asymmetric reaction to shocks, providing a highly flexible representation of market dynamics.
This paper proposes an hybrid model where ANN and RGARCH are used to forecast stock return volatility. This model was established by entering the predicted Realized Volatility (RV), calculated using RGARCH, into the ANN. The choice of the input variables of the ANN is made using the Granger causality test in order to reduce the noise which would affect the prediction system and which could be generated by an input variable not statistically linked to stock market volatility.
The results show that a hybrid model based on a recurrent neural network (RNN) outperforms the RGARCH and HAR-type models in out-of-sample evaluations according to the RMSE and the correlation coefficient.A deep multitask learning approach for air quality predictionhttps://zbmath.org/1530.620382024-04-15T15:10:58.286558Z"Sun, Xiaotong"https://zbmath.org/authors/?q=ai:sun.xiaotong"Xu, Wei"https://zbmath.org/authors/?q=ai:xu.wei.11"Jiang, Hongxun"https://zbmath.org/authors/?q=ai:jiang.hongxun"Wang, Qili"https://zbmath.org/authors/?q=ai:wang.qiliSummary: Air pollution is one of the most serious threats to human health and is an issue causing growing public concern. Air quality forecasts play a fundamental role in providing decision-making support for environmental governance and emergency management, and there is an imperative need for more accurate forecasts. In this paper, we propose a novel spatial-temporal deep multitask learning (ST-DMTL) framework for air quality forecasting based on dynamic spatial panels of multiple data sources. Specifically, we develop a prediction model by combining multitask learning techniques with recurrent neural network (RNN) models and perform empirical analyses to evaluate the utility of each facet of the proposed framework based on a real-world dataset that contains 451,509 air quality records that were generated on an hourly basis from January 2013 to September 2017 in China. An application check is also conducted to verify the practical value of our proposed ST-DMTL framework. Our empirical results indicate the efficacy of the framework as a viable approach for air quality forecasts.Separation of roots of systems of nonlinear equations. Stochastic approachhttps://zbmath.org/1530.650132024-04-15T15:10:58.286558Z"Ermakov, S. M."https://zbmath.org/authors/?q=ai:ermakov.sergei-mikhailovich"Leora, S. N."https://zbmath.org/authors/?q=ai:leora.svetlana-nSummary: In this work, we consider the actual problem of separating the roots of nonlinear systems of equations in the case of many variables. The known method of reducing the problem of solving the system to an equivalent extremal problem, which is supposed to be solved by one of the stochastic optimization methods, is used. As the latter, the modeling method of annealing simulation and its modification, which are especially interesting because they allow effective implementation on quantum computers, are chosen. Since quantum computers based on simulated annealing demonstrate quantum superiority, the obtained results can be useful in solving systems of equations on these computers.Stability of stochastic delay switched neural networks with all unstable subsystems: a multiple discretized Lyapunov-Krasovskii functionals methodhttps://zbmath.org/1530.650162024-04-15T15:10:58.286558Z"Xiao, Hanni"https://zbmath.org/authors/?q=ai:xiao.hanni"Zhu, Quanxin"https://zbmath.org/authors/?q=ai:zhu.quanxin"Karimi, Hamid Reza"https://zbmath.org/authors/?q=ai:karimi.hamidreza-r|karimi.hamid-rezaSummary: This paper considers switching stochastic delay neural networks (SSDNNs) with all unstable subsystems. By using discretized Lyapunov-Krasovskii functions (DLKFs) combined with the dwell time method, exponential stability of SSDNNs with all unstable subsystems are analyzed, and several novel stability criteria in mean square are obtained. Comparing with the existing works, our results focus on all unstable subsystems rather than other combinations such as all stable or partially stable subsystems, which is of more research significance. Finally, the correctness of the conclusion is checked by the feasible solutions of two numerical examples.Efficient construction of 2-chains representing a basis of \(H_{2}(\overline{\Omega}, \partial{\Omega}; \mathbb{Z})\)https://zbmath.org/1530.650202024-04-15T15:10:58.286558Z"Alonso Rodríguez, Ana"https://zbmath.org/authors/?q=ai:alonso-rodriguez.ana"Bertolazzi, Enrico"https://zbmath.org/authors/?q=ai:bertolazzi.enrico"Ghiloni, Riccardo"https://zbmath.org/authors/?q=ai:ghiloni.riccardo"Specogna, Ruben"https://zbmath.org/authors/?q=ai:specogna.rubenLet $\Omega$ be a connected open subset of ${\mathbb R}^3$ whose closure $\overline\Omega$ is a polyhedron with locally flat boundary $\partial\Omega$, and let ${\mathcal T}$ be a triangulation of $\overline\Omega$. The authors present an algorithm for constructing a collection of 1-cycles from $\mathcal{T}$ that lie within $\partial\Omega$ and whose classes in the first integral homology group $H_1(\overline\Omega)$ are trivial, and whose classes in $H_1(\mathbb{R}^3\setminus\Omega)$ form a basis.
This result extends the algorithm of \textit{R. Hiptmair} and \textit{J. Ostrowski} [SIAM J. Comput. 31, No. 5, 1405--1423 (2002; Zbl 1001.05046)] to include the case when $\partial\Omega$ is not connected. Moreover, this result can be combined with the authors' previous work on constructing homological Seifert surfaces [\textit{A. A. Rodríguez} et al., SIAM J. Numer. Anal. 55, No. 3, 1159--1187 (2017; Zbl 1385.55001)] to yield an algorithm for computing generators for the relative homology group $H_2(\overline\Omega,\partial\Omega)$ with respect to $\mathcal{T}$. The results of numerical experiments are presented that indicate the efficiency of the algorithm.
Reviewer: Jason Hanson (Redmond)On \(C^0\) and \(C^1\) continuity of envelopes of rotational solids and its application to 5-axis CNC machininghttps://zbmath.org/1530.650252024-04-15T15:10:58.286558Z"Ponce-Vanegas, Felipe"https://zbmath.org/authors/?q=ai:ponce-vanegas.felipe-e"Bizzarri, Michal"https://zbmath.org/authors/?q=ai:bizzarri.michal"Bartoň, Michael"https://zbmath.org/authors/?q=ai:barton.michael-hSummary: We study the smoothness of envelopes generated by motions of rotational rigid bodies in the context of 5-axis Computer Numerically Controlled (CNC) machining. A moving cutting tool, conceptualized as a rotational solid, forms a surface, called envelope, that delimits a part of 3D space where the tool engages the material block. The smoothness of the resulting envelope depends both on the smoothness of the motion and smoothness of the tool. While the motions of the tool are typically required to be at least \(C^2\), the tools are frequently only \(C^0\) continuous, which results in discontinuous envelopes. In this work, we classify a family of instantaneous motions that, in spite of only \(C^0\) continuous shape of the tool, result in \(C^0\) continuous envelopes. We show that such motions are flexible enough to follow a free-form surface, preserving tangential contact between the tool and surface along two points, therefore having applications in shape slot milling or in a semi-finishing stage of 5-axis flank machining. We also show that \(C^1\) tools and motions still can generate smooth envelopes.Partial fraction decomposition for rational Pythagorean hodograph curveshttps://zbmath.org/1530.650262024-04-15T15:10:58.286558Z"Schröcker, Hans-Peter"https://zbmath.org/authors/?q=ai:schrocker.hans-peter"Šír, Zbyněk"https://zbmath.org/authors/?q=ai:sir.zbynekSummary: All rational parametric curves with prescribed polynomial tangent direction form a vector space. Via tangent directions with rational norm, this includes the important case of rational Pythagorean hodograph curves. We study vector subspaces defined by fixing the denominator polynomial and describe the construction of canonical bases for them. We also show (as an analogy to the fraction decomposition of rational functions) that any element of the vector space can be obtained as a finite sum of curves with single roots at the denominator. Our results give insight into the structure of these spaces, clarify the role of their polynomial and truly rational (non-polynomial) curves, and suggest applications to interpolation problems.Topological classification of the intersection curves of two quadrics using a set of discriminantshttps://zbmath.org/1530.650272024-04-15T15:10:58.286558Z"Shao, Wenbing"https://zbmath.org/authors/?q=ai:shao.wenbing"Chen, Falai"https://zbmath.org/authors/?q=ai:chen.falaiSummary: Computing the intersection curves of two quadrics (QSIC) is a fundamental problem in computer aided design system, where the topology analysis of the QSIC is an essential task to realize the robust computation. In this paper, a new method is proposed to classify the topology of the QSIC in three dimensional projective space by using a set of discriminants associated with the two quadrics. The new topology classification method presents explicit representations and can be applied even when the coefficients of the two quadrics contain symbols. Some examples are provided to illustrate the usage of the new classification method.A complementary topographic feature detection algorithm based on surface curvature for three-dimensional level-set functionshttps://zbmath.org/1530.650302024-04-15T15:10:58.286558Z"Lenz, Christoph"https://zbmath.org/authors/?q=ai:lenz.christoph"Aguinsky, Luiz Felipe"https://zbmath.org/authors/?q=ai:aguinsky.luiz-felipe"Hössinger, Andreas"https://zbmath.org/authors/?q=ai:hossinger.andreas"Weinbub, Josef"https://zbmath.org/authors/?q=ai:weinbub.josefA plethora of disciplines use the level-set method in expanding front simulation. In particular, in microelectronics, this method becomes useful because the critical points of the resulting surfaces must be accurately computed. The developed algorithm has two advantages: (a) an efficient extension of the standard curvature calculation method for level-set functions, and (b) an often ignored approach for computing the curvature due to low numerical accuracy. The algorithms can detect features on geometric stemming and can be applied to surface simplification.
Reviewer: Ioannis Argyros (Lawton)Pseudospectral shattering, the sign function, and diagonalization in nearly matrix multiplication timehttps://zbmath.org/1530.650392024-04-15T15:10:58.286558Z"Banks, Jess"https://zbmath.org/authors/?q=ai:banks.jess"Garza-Vargas, Jorge"https://zbmath.org/authors/?q=ai:garza-vargas.jorge"Kulkarni, Archit"https://zbmath.org/authors/?q=ai:kulkarni.archit"Srivastava, Nikhil"https://zbmath.org/authors/?q=ai:srivastava.nikhilSummary: We exhibit a randomized algorithm which, given a square matrix \(A\in \mathbb{C}^{n\times n}\) with \(\Vert A\Vert \le 1\) and \(\delta >0\), computes with high probability an invertible \(V\) and diagonal \(D\) such that \(\Vert A-VDV^{-1}\Vert \le \delta\) using \(O(T_\mathsf{MM}(n)\log^2(n/\delta ))\) arithmetic operations, in finite arithmetic with \(O(\log^4(n/\delta )\log n)\) bits of precision. The computed similarity \(V\) additionally satisfies \(\Vert V\Vert \Vert V^{-1}\Vert \le O(n^{2.5}/\delta )\). Here \(T_\mathsf{MM}(n)\) is the number of arithmetic operations required to multiply two \(n\times n\) complex matrices numerically stably, known to satisfy \(T_\mathsf{MM}(n)=O(n^{\omega +\eta })\) for every \(\eta >0\) where \(\omega\) is the exponent of matrix multiplication
[\textit{J. Demmel} et al., Numer. Math. 108, No. 1, 59--91 (2007; Zbl 1133.65015)].
The algorithm is a variant of the spectral bisection algorithm in numerical linear algebra
[\textit{A. N. Beavers jun.} and \textit{E. D. Denman}, Math. Biosci. 21, 143--169 (1974; Zbl 0285.15012)]
with a crucial Gaussian perturbation preprocessing step. Our result significantly improves the previously best-known provable running times of \(O(n^{10}/\delta^2)\) arithmetic operations for diagonalization of general matrices
[\textit{D. Armentano} et al., J. Eur. Math. Soc. (JEMS) 20, No. 6, 1375--1437 (2018; Zbl 1401.65034)]
and (with regard to the dependence on \(n)\) \(O(n^3)\) arithmetic operations for Hermitian matrices
[\textit{T. J. Dekker} and \textit{J. F. Traub}, Linear Algebra Appl. 4, 137--154 (1971; Zbl 0214.41005)].
It is the first algorithm to achieve nearly matrix multiplication time for diagonalization in any model of computation (real arithmetic, rational arithmetic, or finite arithmetic), thereby matching the complexity of other dense linear algebra operations such as inversion and \textit{QR} factorization up to polylogarithmic factors. The proof rests on two new ingredients. (1) We show that adding a small complex Gaussian perturbation to \textit{any} matrix splits its pseudospectrum into \(n\) small well-separated components. In particular, this implies that the eigenvalues of the perturbed matrix have a large minimum gap, a property of independent interest in random matrix theory. (2) We give a rigorous analysis of Roberts' Newton iteration method
[\textit{J. D. Roberts}, Int. J. Control 32, 677--687 (1980; Zbl 0463.93050)]
for computing the sign function of a matrix in finite arithmetic, itself an open problem in numerical analysis since at least 1986.Validated numerical approximation of stable manifolds for parabolic partial differential equationshttps://zbmath.org/1530.651052024-04-15T15:10:58.286558Z"van den Berg, Jan Bouwe"https://zbmath.org/authors/?q=ai:van-den-berg.jan-bouwe"Jaquette, Jonathan"https://zbmath.org/authors/?q=ai:jaquette.jonathan"Mireles James, Jason D."https://zbmath.org/authors/?q=ai:mireles-james.jason-dSummary: This paper develops validated computational methods for studying infinite dimensional stable manifolds at equilibrium solutions of parabolic PDEs, synthesizing disparate errors resulting from numerical approximation. To construct our approximation, we decompose the stable manifold into three components: a finite dimensional slow component, a fast-but-finite dimensional component, and a strongly contracting infinite dimensional ``tail''. We employ the parameterization method in a finite dimensional projection to approximate the slow-stable manifold, as well as the attached finite dimensional invariant vector bundles. This approximation provides a change of coordinates which largely removes the nonlinear terms in the slow stable directions. In this adapted coordinate system we apply the Lyapunov-Perron method, resulting in mathematically rigorous bounds on the approximation errors. As a result, we obtain significantly sharper bounds than would be obtained using only the linear approximation given by the eigendirections. As a concrete example we illustrate the technique for a 1D Swift-Hohenberg equation.The strategy of modeling and solving the problems described by Laplace's equation with uncertainly defined boundary shape and boundary conditionshttps://zbmath.org/1530.651132024-04-15T15:10:58.286558Z"Zieniuk, Eugeniusz"https://zbmath.org/authors/?q=ai:zieniuk.eugeniusz"Czupryna, Marta"https://zbmath.org/authors/?q=ai:czupryna.martaSummary: This paper presents a new method for simultaneous modeling the uncertainty of measurement data (necessary to define the boundary shape and boundary conditions) in boundary problems. The interval parametric integral equation system (interval PIES) was developed for solving boundary problems with input data defined in this way. The motivation for conducting this research was that this topic (simultaneous consideration of uncertainties of all input data) has appeared sporadically in the literature (mainly with uncertainly defined boundary conditions or other parameters). In this paper, the uncertainty was defined using interval numbers and modeled using interval arithmetic. The direct application of both classical and directed interval arithmetic caused the overestimation and obtained solutions were useless in practice. Therefore, modification of the directed interval arithmetic was developed. The reliability of the interval PIES solutions obtained using such arithmetic was verified on 2D problems described by Laplace's equation. The solutions were compared with the interval analytical solutions (differently obtained), as well as with the solutions of exactly defined (without the uncertainty) numerical methods. All performed tests indicated the high potential of the method. Obtained interval solutions occurred to be less overestimated and not as time-consuming as presented alternative methods.Three ways to solve partial differential equations with neural networks -- a reviewhttps://zbmath.org/1530.651372024-04-15T15:10:58.286558Z"Blechschmidt, Jan"https://zbmath.org/authors/?q=ai:blechschmidt.jan"Ernst, Oliver G."https://zbmath.org/authors/?q=ai:ernst.oliver-gSummary: Neural networks are increasingly used to construct numerical solution methods for partial differential equations. In this expository review, we introduce and contrast three important recent approaches attractive in their simplicity and their suitability for high-dimensional problems: physics-informed neural networks, methods based on the Feynman-Kac formula and methods based on the solution of backward stochastic differential equations. The article is accompanied by a suite of expository software in the form of Jupyter notebooks in which each basic methodology is explained step by step, allowing for a quick assimilation and experimentation. An extensive bibliography summarizes the state of the art.
{\copyright} 2021 The Authors. \textit{GAMM - Mitteilungen} published by Wiley-VCH GmbH.Discontinuity computing using physics-informed neural networkshttps://zbmath.org/1530.651382024-04-15T15:10:58.286558Z"Liu, Li"https://zbmath.org/authors/?q=ai:liu.li.15"Liu, Shengping"https://zbmath.org/authors/?q=ai:liu.shengping"Xie, Hui"https://zbmath.org/authors/?q=ai:xie.hui"Xiong, Fansheng"https://zbmath.org/authors/?q=ai:xiong.fansheng"Yu, Tengchao"https://zbmath.org/authors/?q=ai:yu.tengchao"Xiao, Mengjuan"https://zbmath.org/authors/?q=ai:xiao.mengjuan"Liu, Lufeng"https://zbmath.org/authors/?q=ai:liu.lufeng"Yong, Heng"https://zbmath.org/authors/?q=ai:yong.hengSummary: Simulating discontinuities has been a long-standing challenge, especially when dealing with shock waves characterized by strong nonlinear features. Despite their promise, the recently developed physics-informed neural networks (PINNs) have not yet fully demonstrated their effectiveness in handling discontinuities when compared to traditional shock-capturing methods. In this study, we reveal a paradoxical phenomenon during the training of PINNs when computing problems with strong nonlinear discontinuities. To address this issue and enhance the PINNs' ability to capture shocks, we propose PINNs-WE (Physics-Informed Neural Networks with Equation Weight) method by introducing three novel strategies. Firstly, we attenuate the neural network's expression locally at `transition points' within the shock waves by introducing a physics-dependent weight into the governing equations. Consequently, the neural network will concentrate on training the smoother parts of the solutions. As a result, due to the compressible property, sharp discontinuities emerge, with transition points being compressed into well-trained smooth regions akin to passive particles. Secondly, we also introduce the Rankine-Hugoniot (RH) relation, which is equivalent to the weak form of the conservation laws near the discontinuity, in order to improve the shock-capturing preformance. Lastly, we construct a global physical conservation constraint to enhance the conservation properties of PINNs which is key to resolve the right position of the discontinuity. To illustrate the impact of our novel approach, we investigate the behavior of the one-dimensional Burgers' equation, as well as the one- and two-dimensional Euler equations. In our numerical experiments, we compare our proposed PINNs-WE method with a traditional high-order weighted essential non-oscillatory (WENO) approach. The results of our study highlight the significant enhancement in discontinuity computing by the PINNs-WE method when compared to traditional PINNs.Accelerated subgradient extragradient methods for variational inequality problemshttps://zbmath.org/1530.651902024-04-15T15:10:58.286558Z"Thong, Duong Viet"https://zbmath.org/authors/?q=ai:duong-viet-thong."Vinh, Nguyen The"https://zbmath.org/authors/?q=ai:vinh.nguyen-the"Cho, Yeol Je"https://zbmath.org/authors/?q=ai:cho.yeol-jeTwo new iterative methods for solving monotone and Lipschitz-continuous variational inequality problems are introduced. The first proposed method combines the inertial subgradient extragradient method and the viscosity method. The second proposed iterative method couples the inertial subgradient extragradient method with the Mann type method. Strong convergence theorems for the proposed algorithms under suitable conditions are exposed. The comparisons with Maingé's method and Kraikaew and Saejung's method in the frame of numerical experiments show the advantages of the new methods, especially in terms of computational time.
Reviewer: Dana Petcu (Timişoara)Handbook of metaheuristic algorithms. From fundamental theories to advanced applicationshttps://zbmath.org/1530.680012024-04-15T15:10:58.286558Z"Tsai, Chun-Wei"https://zbmath.org/authors/?q=ai:tsai.chun-wei"Chiang, Ming-Chao"https://zbmath.org/authors/?q=ai:chiang.ming-chaoThe changing speed of the digital century is of tremendously high speed. Introduced technical digital terms and words vocabulary double the volume of the daily English dictionary. Optimization problems are ubiquitous. In general, in optimization problems the goal is to find the best solution from a large number of possible solutions in a given solution space. In daily live we face mainly two types of problems we can categorize as: those that can be solved intuitively and those that cannot be solved intuitively. In contrast to the problems that can be solved intuitively, many complex and/or large-scale optimization problems cannot be solved intuitively. Because all these problems have a common characteristic, a very large solution space that is composed of a huge number of candidate solutions for the optimization problem. Which one of these solutions is the best intuitively? Because it is like looking for a needle in a haystack.
The present book provides resources, references and alternative ways of simple and fast solution methods and algorithms. It is organized in such a way that the readers can not only realize most of the metaheuristic algorithms, but also use them to solve real-world problems. The book can be used by students and researchers as a reference for self-study to enter this research domain or by teachers as a reference or textbook for a course. It does not cover all metaheuristic algorithms; even then, it provides insight into the metaheuristic algorithms and it is expected that people who read the whole book will have no difficulty to understand metaheuristic algorithms not covered in this book. The book is roughly divided into three parts: fundamentals, advanced technologies, and an appendix. The ultimate goal of the book is to share with the audience the authors' experience and know-how on metaheuristic algorithms from the ground up, that is, from the basic ideas to advanced technologies, even for readers who have no background knowledge in artificial intelligence or machine learning. There exists a gap between theory and implementation in this research domain. To narrow down this gap, the authors first present a unified framework for metaheuristics (UFM) and then use it to describe well-known metaheuristic algorithms and their variants. Especially, to make it easier for the audience of this book to understand how the metaheuristic algorithms and advanced technologies discussed herein are realized, the source code is developed from scratch based on the UFM. The book is arranged in a way that it makes it very easy to realize most metaheuristic algorithms for solving various optimization problems -- be it discrete or continuous. Theory and programming arrangement within the book is in such a way that there should be no obstacle for students and researchers who are interested in entering this research domain. In this third version of the book, the aim is to make implementation as simple and thus as easy to understand as possible, so there are chances that the audience of this book will have no difficulty to understand not only the theory but also the implementation of a set of representative metaheuristic algorithms.
Reviewer: Haydar Akca (Abu Dhabi)Machine learning. The basicshttps://zbmath.org/1530.680022024-04-15T15:10:58.286558Z"Jung, Alexander"https://zbmath.org/authors/?q=ai:jung.alexander-wolfgang|jung.alexander-rThe book under review matured from lecture notes prepared by the author for several machine learning modules taught at Aalto University. The structure and style strongly recommend the book as a thorough entry point for studying ML; the exercises and the references concluding each chapter reinforce concepts and also provide a curated guidance for further steps. The book comprises ten chapters, organised incrementally. Starting with an introduction that positions ML in the context of other fields, such as linear algebra, optimisation and information theory, the author overviews next the three main favours of ML: supervised, unsupervised and reinforcement learning. In the second chapter the components of ML are discussed: the data, the model and the loss function, followed by a summary of the ML landscape in the third chapter. The next four sections focus on generic assessment of ML models such as empirical risk minimisation (Chapter 4), gradient-based learning (Chapter 5), model validation and selection (Chapter 6) and regularisation (Chapter 7). The eighth chapter explores unsupervised learning (clustering) with comments on both crisp and fuzzy clustering. Next, feature learning is discussed with focus on dimensionality reduction (PCA and extensions) and augmentation (for kernelization tasks); links with supervised learning are also underlined. The book concludes with the tenth chapter on transparent and explainable ML, which links concepts presented earlier, such as the model agnostic method and explainable empirical risk minimisation.
The (text)book reaches a balance between mathematical details, overview of algorithms and examples, making it suitable for a wide range of readers, and further underlining the interdisciplinary character of machine learning.
Reviewer: Irina Ioana Mohorianu (Oxford)Concise guide to quantum machine learninghttps://zbmath.org/1530.680032024-04-15T15:10:58.286558Z"Pastorello, Davide"https://zbmath.org/authors/?q=ai:pastorello.davideThe book under review summarises lecture notes presented by the author for the quantum machine learning MSc course at the University of Trento; it is therefore structured in a student-friendly manner, offering support both on the mathematical side (also with the interpretation of quantum mechanics) and on the algorithmic side. The book is structured into ten chapters. The author commences with an overview of quantum mechanics (Chapter 2) focusing on the phenomenology, the mathematical framework and the definitions and properties of quantum states and observables. Next, he progresses to quantum computing, describing, in Chapter 3, quantum circuits and oracles alongside the principles of adiabatic quantum computing and quantum annealing. The theoretical section of the book concludes with a summary of relevant quantum algorithms such as the quantum Fourier transform, Grover's search algorithm and the quantum phase estimation.
In the second, more applied section of the book, the author first introduces the QML toolkit (Chapter 5), focusing on Hamiltonian simulations, SWAP tests and the Qdist routine. The next two chapters focus on a quantum take on unsupervised learning/clustering (Chapter 6) and supervised learning/classification (Chapter 7). Yet another angle is reviewed in Chapter 8, where approaches for quantum pattern recognition are presented (quantum associative memory, adiabatic pattern recognition), and Chapter 9 focuses on quantum neural networks. Several aspects are discussed, including the quantum perceptron, the feedforward neural network, and the convolutional and generative adversarial neural networks, all from a quantum perspective. The book concludes with an extensive, well-curated set of references, which represent an excellent continuation of quantum approaches.
Reviewer: Irina Ioana Mohorianu (Oxford)Thinking data science. A data science practitioner's guidebookhttps://zbmath.org/1530.680042024-04-15T15:10:58.286558Z"Sarang, Poornachandra"https://zbmath.org/authors/?q=ai:sarang.poornachandraThe book is structured as a methodical overview of current data science and machine learning methods applicable across datasets. It is structured into 20 chapters, and it starts and ends with frameworks (Chapter 1) and advice (Chapter 20) for handling large datasets in a computationally robust manner. The first chapter focuses on processing steps such as data preparation, exploratory analyses and narrowing the list of models that would be applicable for a given setting. The author also introduces concepts such as parameter tuning or models based on transfer learning, which are further discussed in subsequent chapters. The second chapter is dedicated to dimensionality reduction; both linear, PCA and nonlinear approaches, tSNE and UMAP are discussed. Comments on singular-value decomposition and linear discriminant analysis conclude the chapter. The rest of the book is structured into three parts on supervised learning (Part I), unsupervised learning (Part II) and artificial neural networks (Part III).
Part I comprises five chapters on regression analysis (Chapter 3), decision trees (Chapter 4) and ensemble methods, bagging and boosting (Chapter 5), k-nearest neighbours (Chapter 6), naïve Bayes (Chapter 7) and support vector machines (Chapter 8). For each of these methods the theory is introduced, with the aid of examples; advantages and disadvantages are also discussed, in tandem with parameter-optimisation approaches. Various flavours of the approaches are overviewed as well.
Part II focuses on clustering algorithms. In Chapter 9 centroid-based methods are discussed (k-means and k-medoids); connectivity-based algorithms (Chapter 10) include both the agglomerative and the divisive approach. In Chapter 11 the author focuses on Gaussian mixture models, with details on the characteristics of the probability distributions and on the selection of the suitable number of clusters. Lastly, in Chapter 12, density-based methods are presented; these include DBSCAN, OPTICS and mean-shift clustering. The subsequent four chapters overview specific frameworks (BIRCH, Chapter 13; CLARA, Chapter 14; affinity propagation clustering, Chapter 15; STING and CLIQUE, Chapter 16) for which the theoretical details are balanced with detailed discussions of pros/cons and applicability.
Part III comprises two chapters and focuses on artificial neural networks. Chapter 17 is built on theoretical aspects of various flavours of ANNs (perceptron approaches, convolutional NNs, generative adversarial networks, recurrent NNs and long short-term memory approaches). Chapter 18 focuses on applications to natural language processing and image-based datasets. The book concludes with a summary on automated tools (such as auto-sklearn, auto-keras and the AutoML framework -- all Python-based). Chapter 20 is structured as a cheat sheet of 11 workflows, serving as a good starting point for more complex analyses.
Most chapters commence with a nutshell summary of the concepts being described; all chapters conclude with a summary, emphasising yet again the essential aspects which were discussed. The pedagogical value of the book is enhanced with numerous examples and snipes of code which connect the theoretical concepts and the real-world applications. The style of the book is accessible to a wide range of readers, and most required concepts are either discussed in the book or are well referenced.
Reviewer: Irina Ioana Mohorianu (Oxford)Dynamic graph learning for dimension reduction and data clusteringhttps://zbmath.org/1530.680052024-04-15T15:10:58.286558Z"Zhu, Lei"https://zbmath.org/authors/?q=ai:zhu.lei"Li, Jingjing"https://zbmath.org/authors/?q=ai:li.jingjing"Zhang, Zheng"https://zbmath.org/authors/?q=ai:zhang.zheng.6|zhang.zheng.4|zhang.zheng|zhang.zheng.7|zhang.zheng.8Publisher's description: This book illustrates how to achieve effective dimension reduction and data clustering. The authors explain how to accomplish this by utilizing the advanced dynamic graph learning technique in the era of big data. The book begins by providing background on dynamic graph learning. The authors discuss why it has attracted considerable research attention in recent years and has become well recognized as an advanced technique. After covering the key topics related to dynamic graph learning, the book discusses the recent advancements in the area. The authors then explain how these techniques can be practically applied for several purposes, including feature selection, feature projection, and data clustering.Complexity dichotomies for counting problems. Volume 1. Boolean domainhttps://zbmath.org/1530.680062024-04-15T15:10:58.286558Z"Cai, Jin-Yi"https://zbmath.org/authors/?q=ai:cai.jin-yi"Chen, Xi"https://zbmath.org/authors/?q=ai:chen.xi.1Publisher's description: Complexity theory aims to understand and classify computational problems, especially decision problems, according to their inherent complexity. This book uses new techniques to expand the theory for use with counting problems. The authors present dichotomy classifications for broad classes of counting problems in the realm of P and NP. Classifications are proved for partition functions of spin systems, graph homomorphisms, constraint satisfaction problems, and Holant problems. The book assumes minimal prior knowledge of computational complexity theory, developing proof techniques as needed and gradually increasing the generality and abstraction of the theory. This volume presents the theory on the Boolean domain, and includes a thorough presentation of holographic algorithms, culminating in classifications of computational problems studied in exactly solvable models from statistical mechanics.Descriptive complexity, canonisation, and definable graph structure theoryhttps://zbmath.org/1530.680072024-04-15T15:10:58.286558Z"Grohe, Martin"https://zbmath.org/authors/?q=ai:grohe.martinPublisher's description: Descriptive complexity theory establishes a connection between the computational complexity of algorithmic problems (the computational resources required to solve the problems) and their descriptive complexity (the language resources required to describe the problems). This groundbreaking book approaches descriptive complexity from the angle of modern structural graph theory, specifically graph minor theory. It develops a `definable structure theory' concerned with the logical definability of graph theoretic concepts such as tree decompositions and embeddings. The first part starts with an introduction to the background, from logic, complexity, and graph theory, and develops the theory up to first applications in descriptive complexity theory and graph isomorphism testing. It may serve as the basis for a graduate-level course. The second part is more advanced and mainly devoted to the proof of a single, previously unpublished theorem: properties of graphs with excluded minors are decidable in polynomial time if, and only if, they are definable in fixed-point logic with counting.Proceedings of the 26th ACM international conference on hybrid systems: computation and control, HSCC 2023, part of the 16th CPS-IoT week, San Antonio, TX, USA, May 9--12, 2023https://zbmath.org/1530.680082024-04-15T15:10:58.286558ZThe articles of this volume will be reviewed individually. For the preceding conference see [Zbl 1492.68007].
Indexed articles:
\textit{Cairoli, Francesca; Paoletti, Nicola; Bortolussi, Luca}, Conformal quantitative predictive monitoring of STL requirements for stochastic processes, Paper No. 1, 11 p. [Zbl 07807942]
\textit{Chen, Hongkai; Smolka, Scott A.; Paoletti, Nicola; Lin, Shan}, An STL-based approach to resilient control for cyber-physical systems, Paper No. 2, 12 p. [Zbl 07807943]
\textit{Cardona, Gustavo A.; Kamale, Disha; Vasile, Cristian-Ioan}, Mixed integer linear programming approach for control synthesis with weighted signal temporal logic, Paper No. 3, 12 p. [Zbl 07807944]
\textit{Tran, Hoang-Dung; Choi, Sungwoo; Okamoto, Hideki; Hoxha, Bardh; Fainekos, Georgios; Prokhorov, Danil}, Quantitative verification for neural networks using probstars, Paper No. 4, 12 p. [Zbl 07807945]
\textit{Wetzlinger, Mark; Kochdumper, Niklas; Bak, Stanley; Althoff, Matthias}, Fully-automated verification of linear systems using reachability analysis with support functions, Paper No. 5, 12 p. [Zbl 07807946]
\textit{Tran, Hoang Dung; Choi, Sung Woo; Yang, Xiaodong; Yamaguchi, Tomoya; Hoxha, Bardh; Prokhorov, Danil}, Verification of recurrent neural networks with star reachability, Paper No. 6, 13 p. [Zbl 07807947]
\textit{Adimoolam, Arvind; Saha, Indranil; Dang, Thao}, Safe self-triggered control based on precomputed reachability sequences, Paper No. 7, 12 p. [Zbl 07807948]
\textit{Debauche, Virginie; Della Rossa, Matteo; Jungers, Raphaël}, Characterization of the ordering of path-complete stability certificates with addition-closed templates, Paper No. 8, 10 p. [Zbl 07807949]
\textit{Zareian, Mehrdad; Schmuck, Anne-Kathrin}, Lazy synthesis of symbolic output-feedback controllers for state-based safety specifications, Paper No. 9, 7 p. [Zbl 07807950]
\textit{Ferdowsi, Arman; Függer, Matthias; Nowak, Thomas; Schmid, Ulrich}, Continuity of thresholded mode-switched ODEs and digital circuit delay models, Paper No. 10, 11 p. [Zbl 07807951]
\textit{Gracia, Ibón; Boskos, Dimitris; Laurenti, Luca; Mazo, Manuel jun.}, Distributionally robust strategy synthesis for switched stochastic systems, Paper No. 11, 10 p. [Zbl 07807952]
\textit{Delimpaltadakis, Giannis; Lahijanian, Morteza; Mazo, Manuel jun.; Laurenti, Luca}, Interval Markov decision processes with continuous action-spaces, Paper No. 12, 10 p. [Zbl 07807953]
\textit{Van Huijgevoort, Birgit; Schön, Oliver; Soudjani, Sadegh; Haesaert, Sofie}, SySCoRe: synthesis via stochastic coupling relations, Paper No. 13, 11 p. [Zbl 07807954]
\textit{Mambakam, Akshay; Asarin, Eugene; Basset, Nicolas; Dang, Thao}, Pattern matching and parameter identification for parametric timed regular expressions, Paper No. 14, 13 p. [Zbl 07807955]
\textit{Chandratre, Aniruddh; Hernandez Acosta, Tomas; Khandait, Tanmay; Pedrielli, Giulia; Fainekos, Georgios}, Stealthy attacks formalized as STL formulas for falsification of CPS security, Paper No. 15, 8 p. [Zbl 07807956]
\textit{Barbot, Benoit; Basset, Nicolas; Donze, Alexandre}, Wordgen: a timed word generation tool, Paper No. 16, 7 p. [Zbl 07807957]
\textit{Luo, Ertai; Kochdumper, Niklas; Bak, Stanley}, Reachability analysis for linear systems with uncertain parameters using polynomial zonotopes, Paper No. 17, 12 p. [Zbl 07807958]
\textit{Ladner, Tobias; Althoff, Matthias}, Automatic abstraction refinement in neural network verification using sensitivity analysis, Paper No. 18, 13 p. [Zbl 07807959]
\textit{Fatnassi, Wael; Khedr, Haitham; Yamamoto, Valen; Shoukry, Yasser}, Bern-NN: tight bound propagation for neural networks using Bernstein polynomial interval arithmetic, Paper No. 19, 11 p. [Zbl 07807960]
\textit{Chong, Stephen; Lanotte, Ruggero; Merro, Massimo; Tini, Simone; Xiang, Jian}, Quantitative robustness analysis of sensor attacks on cyber-physical systems, Paper No. 20, 12 p. [Zbl 07807961]
\textit{Das, Spandan; Prabhakar, Pavithra}, Poster abstract: Stability analysis of planar probabilistic piecewise constant derivative systems, Paper No. 21, 2 p. [Zbl 07807962]
\textit{Schön, Oliver; Van Huijgevoort, Birgit; Haesaert, Sofie; Soudjani, Sadegh}, Poster abstract: Data-driven correct-by-design control of parametric stochastic systems, Paper No. 22, 2 p. [Zbl 07807963]
\textit{Raz, Daphna; Yang, Liren; Umberger, Brian; Ozay, Necmiye}, Poster abstract: Reachability and controlled invariance for human stability during sit-to-stand, Paper No. 23, 2 p. [Zbl 07807964]
\textit{Karagulle, Ruya; Arechiga, Nikos; Best, Andrew; Decastro, Jonathan; Ozay, Necmiye}, Poster abstract: Safety guaranteed preference learning approach for autonomous vehicles, Paper No. 24, 2 p. [Zbl 07807965]
\textit{Ho, Qi Heng; Ilyes, Roland; Sunberg, Zachary; Lahijanian, Morteza}, Poster abstract: Sampling-based approach to robust STL synthesis for complex systems under uncertainty, Paper No. 25, 2 p. [Zbl 07807966]
\textit{Peruffo, Andrea; Mazo, Manuel jun.}, Poster: Convex scenario optimisation for ReLU networks, Paper No. 26, 2 p. [Zbl 07807967]
\textit{Egidio, Lucas Neves; Nayak, Satya Prakash; Rossa, Matteo Della; Schmuck, Anne-Kathrin; Jungers, Raphaël}, Poster abstract: Towards seamless reactivity of hybrid control, Paper No. 27, 2 p. [Zbl 07807968]
\textit{Majumdar, Rupak; Mallik, Kaushik; Rychlicki, Mateusz; Schmuck, Anne-Kathrin; Soudjani, Sadegh}, Poster abstract: A toolchain for accelerated symbolic control, Paper No. 28, 2 p. [Zbl 07807969]
\textit{Anand, Ashwani; Nayak, Satya Prakash; Schmuck, Anne-Kathrin}, Poster abstract: Permissiveness for strategy adaptation, Paper No. 29, 2 p. [Zbl 07807970]
\textit{Khandait, Tanmay; Chandratre, Aniruddh; Baptista, Walstan; Pedrielli, Giulia; Fainekos, Georgios}, Demo abstract: Analysing CPS security with falsification on the Microsoft flight simulator, Paper No. 30, 2 p. [Zbl 07807971]Prefacehttps://zbmath.org/1530.680092024-04-15T15:10:58.286558ZFrom the text: This special issue of Natural Computing is dedicated to cellular automata and related systems. It is based on AUTOMATA 2018, the 24th International Workshop on Cellular Automata and Discrete Complex Systems, held in Ghent, Belgium, June 20--22, 2018.Proceedings of the 2nd SIAM conference on applied and computational discrete algorithms, ACDA'23, Seattle, WA, USA, May 31 -- June 2, 2023https://zbmath.org/1530.680102024-04-15T15:10:58.286558ZThe articles of mathematical interest will be reviewed individually. For the preceding conference see [Zbl 1466.68008].Preface. Special issue on ``Understanding of evolutionary optimization behavior''. IIhttps://zbmath.org/1530.680112024-04-15T15:10:58.286558ZFor Part I of this special issue see [Zbl 1530.68012].Preface. Special issue on ``Understanding of evolutionary optimization behavior''. Ihttps://zbmath.org/1530.680122024-04-15T15:10:58.286558Z(no abstract)Programming language implementation and logic programming. 4th international symposium, PLILP '92, Leuven, Belgium, August 26--28, 1992. Proceedingshttps://zbmath.org/1530.680132024-04-15T15:10:58.286558ZThe articles of this volume will not be indexed individually. For the preceding symposium see [Zbl 0768.00015].Prefacehttps://zbmath.org/1530.680142024-04-15T15:10:58.286558ZFrom the text: The present special issue of Natural Computing is dedicated to the study of algebraic, dynamical, algorithmic and complexity-theoretic aspects of cellular automata (CA) and discrete complex systems (DCS). It contains six extended and improved versions of selected papers presented at the 25\(^\text{th}\) International Workshop on Cellular Automata and Discrete Complex Systems, AUTOMATA 2019, held on June 26\(^\text{th}\)--28\(^\text{th}\), 2019, at the University Center of Exact Sciences and Engineering, University of Guadalajara, Mexico.Proceedings of the 17th ACM/SIGEVO workshop on foundations of genetic algorithms, FOGA 2023, Potsdam, Germany, August 30 -- September 1, 2023https://zbmath.org/1530.680152024-04-15T15:10:58.286558ZThe articles of mathematical interest will be reviewed individually. For the preceding workshop see [Zbl 1470.68013].
Indexed articles:
\textit{Lozano, José A.}, Analyzing the Fourier representation of permutation-based combinatorial optimization problems, 1 [Zbl 07809158]
\textit{Doerr, Carola}, Bridging theory and practice in evolutionary computation?, 2 [Zbl 07809159]
\textit{Antipov, Denis; Neumann, Aneta; Neumann, Frank}, Rigorous runtime analysis of diversity optimization with GSEMO on OneMinMax, 3-14 [Zbl 07809160]
\textit{Antonov, Kirill; Kononova, Anna V.; Bäck, Thomas; van Stein, Niki}, Curing ill-conditionality via representation-agnostic distance-driven perturbations, 15-26 [Zbl 07809161]
\textit{Branson, Luke; Sutton, Andrew M.; Yan, Xiankun}, Finding antimagic labelings of trees by evolutionary search, 27-37 [Zbl 07809162]
\textit{Chen, Deyao; Buzdalov, Maxim; Doerr, Carola; Dang, Nguyen}, Using automated algorithm configuration for parameter control, 38-49 [Zbl 07809163]
\textit{Cui, Henning; Pätzel, David; Margraf, Andreas; Hähner, Jörg}, Weighted mutation of connections to mitigate search space limitations in Cartesian genetic programming, 50-60 [Zbl 07809164]
\textit{Fischer, Paul; Larsen, Emil Lundt; Witt, Carsten}, First steps towards a runtime analysis of neuroevolution, 61-72 [Zbl 07809165]
\textit{Fajardo, Mario Alejandro Hevia; Lehre, Per Kristian; Lin, Shishen}, Runtime analysis of a co-evolutionary algorithm. Overcoming negative drift in maximin-optimisation, 73-83 [Zbl 07809166]
\textit{Kalkreuth, Roman; Vašíček, Zdeněk; Husa, Jakub; Vermetten, Diederick; Ye, Furong; Bäck, Thomas}, General Boolean function benchmark suite, 84-95 [Zbl 07809167]
\textit{Kearney, Jack; Neumann, Frank; Sutton, Andrew M.}, Fixed-parameter tractability of the (1 + 1) evolutionary algorithm on random planted vertex covers, 96-104 [Zbl 07809168]
\textit{Lehre, Per Kristian; Qin, Xiaoyu}, Self-adaptation can improve the noise-tolerance of evolutionary algorithms, 105-116 [Zbl 07809169]
\textit{Omeradzic, Amir; Beyer, Hans-Georg}, Convergence properties of the \((\mu/\mu_i,\lambda)\)-ES on the Rastrigin function, 117-128 [Zbl 07809170]
\textit{Prager, Raphael Patrick; Dietrich, Konstantin; Schneider, Lennart; Schäpermeier, Lennart; Bischl, Bernd; Kerschke, Pascal; Trautmann, Heike; Mersmann, Olaf}, Neural networks as black-box benchmark functions optimized for exploratory landscape features, 129-139 [Zbl 07809171]
\textit{Scott, Eric O.; De Jong, Kenneth A.}, First complexity results for evolutionary knowledge transfer, 140-151 [Zbl 07809172]
\textit{Whitley, Darrell; Ochoa, Gabriela; Chicano, Francisco}, Partition crossover can linearize local optima lattices of k-bounded pseudo-Boolean functions, 152-162 [Zbl 07809173]Proceedings of the 26th symposium on algorithm engineering and experiments, ALENEX '24, took place in conjunction with SODA '24, Alexandria, VA, USA, January 7--8, 2024https://zbmath.org/1530.680162024-04-15T15:10:58.286558ZThe articles of mathematical interest will be reviewed individually. For the preceding symposium see [Zbl 1508.68010].Prefacehttps://zbmath.org/1530.680172024-04-15T15:10:58.286558ZFrom the text: This special issue of Natural Computing is devoted to the 22nd International Workshop on Cellular Automata and Discrete Complex Systems (AUTOMATA 2016), and includes extended versions of a selection of papers presented at the conference.Mathematical methods for objects reconstruction. From 3D vision to 3D printing. Selected contributions from the INdAM workshop, online, February 10--12, 2021https://zbmath.org/1530.680182024-04-15T15:10:58.286558ZPublisher's description: The volume collects several contributions to the INDAM workshop Mathematical Methods for Objects Reconstruction: from 3D Vision to 3D Printing held in Rome, February, 2021.
The goal of the workshop was to discuss new methods and conceptual structures for managing these challenging problems. The chapters reflect this goal and the authors are academic researchers and some experts from industry working in the areas of 3D modeling, computer vision, 3D printing and/or developing new mathematical methods for these problems. The contributions present methodologies and challenges raised by the emergence of large-scale 3D reconstruction applications and low-cost 3D printers. The volume collects complementary knowledges from different areas of mathematics, computer science and engineering on research topics related to 3D printing, which are, so far, widely unexplored.
Young researchers and future scientific leaders in the field of 3D data acquisition, 3D scene reconstruction, and 3D printing software development will find an excellent introduction to these problems and to the mathematical techniques necessary to solve them.
The articles of this volume will not be indexed individually.Prefacehttps://zbmath.org/1530.680192024-04-15T15:10:58.286558ZFrom the text: This special issue presents three papers from the Fourth International Workshop on Asynchronous Cellular Automata (ACA 2016) which was held in Fez, Morocco, September 5th--8th, 2016 as a satellite event of the 12th International Conference on Cellular Automata for Research and Industry (ACRI 2016).Prefacehttps://zbmath.org/1530.680202024-04-15T15:10:58.286558ZFrom the text: This special issue of Natural Computing is associated with the 24th International Conference on DNA Computing and Molecular Programming, held October 8--12, 2018 at Shandong Normal University in Jinan, China. Six papers were invited from the conference that had been presented in preliminary form at the conference. One paper was withdrawn, and this issue contains the five remaining papers.Prefacehttps://zbmath.org/1530.680212024-04-15T15:10:58.286558ZFrom the text: This special issue is devoted to all aspects of unconventional computation and natural computation.Introduction to the collection of papers celebrating the 20th anniversary of TPLPhttps://zbmath.org/1530.680222024-04-15T15:10:58.286558Z(no abstract)Prefacehttps://zbmath.org/1530.680232024-04-15T15:10:58.286558ZFrom the text: This special issue presents bio-inspired computing approaches, such as evolutionary algorithms and other Artificial Intelligence techniques, such as planning or learning, to solve a number of difficult problems in protein structure prediction, scheduling, mobile computing, recommender systems and robotics. It includes six papers that are extended versions of papers selected from the IWINAC 2019 conference held in Almería (Spain) in June 2019. A total of nine papers were preselected and finally six of them were accepted after a thorough revision process.Introduction to the special issue on the international joint conference on rules and reasoning, RuleML+RR 2019https://zbmath.org/1530.680242024-04-15T15:10:58.286558ZSummary: This special issue of Theory and Practice of Logic Programming consists of extended versions of five selected papers from the 3rd International Joint Conference on Rules and Reasoning (RuleML+RR 2019). RuleML+RR 2019 was held in conjunction with the 5th Global Conference on Artificial Intelligence, GCAI 2019, as part of the Bolzano Rules and Artificial Intelligence Summit in Bolzano, Italy, from 17 to 19 of September 2019.Prefacehttps://zbmath.org/1530.680252024-04-15T15:10:58.286558ZFrom the text: This special issue was initiated at the 4th French-speaking meeting on Interaction Networks -- Foundations and Applications to Biology that took place at the CIRM in Marseilles in January 3rd--6th, 2017. This meeting was dedicated to Prof. Jacques Demongeot, on the occasion of his 70th birthday, a French physician and mathematician who is a pioneer in using discrete dynamical systems, in particular automata networks, in the framework of modelling complex biological systems. Moreover, in order to provide a more comprehensive presentation of the field, this special issue was not limited to articles related to talks given during the meeting (an international call for participations was widely distributed through multiple channels).Programming languages: implementations, logics, and programs. 9th international symposium, PLILP '97, including a special track on declarative programming languages in education, Southampton, UK, September 3--5, 1997. Proceedingshttps://zbmath.org/1530.680262024-04-15T15:10:58.286558ZThe articles of this volume will not be indexed individually. For the preceding symposium see [Zbl 1530.68032].Prefacehttps://zbmath.org/1530.680272024-04-15T15:10:58.286558ZFrom the text: This special issue collects extended and revised versions of selected papers presented at the 14th International Conference and School ``Cellular Automata for Research and Industry'' (ACRI 2020) organized by the Faculty of Physics and Applied Informatics of the University of Lodz, Poland.Programming languages: implementations, logics and programs. 7th international symposium, PLILP '95, Utrecht, the Netherlands, September 20--22, 1995. Proceedingshttps://zbmath.org/1530.680282024-04-15T15:10:58.286558ZThe articles of this volume will not be indexed individually. For the preceding symposium see [Zbl 0802.00047].NACO special issue editorialhttps://zbmath.org/1530.680292024-04-15T15:10:58.286558ZFrom the text: The 13th European Conference on Artificial Life (ECAL 2015) was held in York, United Kingdom, 20--24 July 2015, hosted by the York Centre for Complex Systems Analysis at the The University of York. ECAL 2015 showcased a wide range of topics in Artificial Life, bringing together world-leading researchers to discuss the latest advance. Artificial Life is an interdisciplinary field, and as such submissions from across the spectrum of scientific and humanities disciplines were presented, that considered the main conference themes of Embodiment, Interaction, Conversation.
This issue of Natural Computing brings together five of the best papers from the conference, as determined by the original review process.Erratum to: ``NACO special issue editorial''https://zbmath.org/1530.680302024-04-15T15:10:58.286558ZFrom the text: The correct authorship for the editorial [ibid. 18, No. 1, 1--2 (2019; Zbl 1530.68029)] should be Simon Hickinbotham, Susan Stepney and Jon Timmis.Prefacehttps://zbmath.org/1530.680312024-04-15T15:10:58.286558ZFrom the text: This special issue of Natural Computing is dedicated to cellular automata and related systems. It is based on AUTOMATA 2015, the 21st International Workshop on Cellular Automata and Discrete Complex Systems. The event was organized by the Department of Mathematics and Statistics of the University of Turku, and it was held in Turku, Finland, in June 8--10, 2015.Programming languages: implementations, logics, and programs. 8th international symposium, PLILP '96, Aachen, Germany, September 24--27, 1996. Proceedingshttps://zbmath.org/1530.680322024-04-15T15:10:58.286558ZThe articles of this volume will not be indexed individually. For the preceding symposium see [Zbl 1530.68028].Prefacehttps://zbmath.org/1530.680332024-04-15T15:10:58.286558ZFrom the text: The aim of this special issue is to promote the development of the interplay between Natural Computing Algorithms (NCAs) and Machine Learning (ML) in a way which highlights recent developments concerning the combination of these two fields, clarifies outstanding issues for future progress, and disseminates this cross-fertilization to a wider audience in order to attract more researchers from other fields.Prefacehttps://zbmath.org/1530.680342024-04-15T15:10:58.286558ZFrom the text: This special issue of the journal Natural Computing contains extended versions of some of the best papers presented at the Eighth International Conference on the Theory and Practice of Natural Computing, TPNC 2019, held in Kingston, Canada on December 9--11, 2019.Prefacehttps://zbmath.org/1530.680352024-04-15T15:10:58.286558ZFrom the text: This special issue of the Journal of Natural Computing consists of extended and revised versions of selected papers presented at ACRI 2018, the 13th International Conference on Cellular Automata for Research and Industry, organized by the Department of Informatics, Systems and Communication of the ``Università degli Studi di Milano-Bicocca'', and held in Como, Italy, September 17--21, 2018.Prefacehttps://zbmath.org/1530.680362024-04-15T15:10:58.286558ZFrom the text: The 18th International Conference on Unconventional Computation and Natural Computation took place in Tokyo, Japan from June 3--7, 2019.
This special edition contains selected papers from the 18th edition of the conference. All papers accepted contain substantial extensions, and they also went through an independent review process.Proceedings of the 42nd ACM symposium on principles of distributed computing, PODC '23, Orlando, FL, USA, June 19--23, 2023https://zbmath.org/1530.680372024-04-15T15:10:58.286558ZThe articles of this volume will be reviewed individually. For the preceding symposium see [Zbl 1492.68024].
Indexed articles:
\textit{Yokota, Daisuke; Sudo, Yuichi; Ooshita, Fukuhito; Masuzawa, Toshimitsu}, A near time-optimal population protocol for self-stabilizing leader election on rings with a poly-logarithmic number of states, 2-12 [Zbl 07824304]
\textit{Amir, Talley; Aspnes, James; Berenbrink, Petra; Biermeier, Felix; Hahn, Christopher; Kaaser, Dominik; Lazarsfeld, John}, Fast convergence of \(k\)-opinion undecided state dynamics in the population protocol model, 13-23 [Zbl 07824305]
\textit{Cosson, Romain; Massoulie, Laurent; Viennot, Laurent}, Brief announcement: Efficient collaborative tree exploration with breadth-first depth-next, 24-27 [Zbl 07824306]
\textit{Czerner, Philipp}, Brief announcement: Population protocols decide double-exponential thresholds, 28-31 [Zbl 07824307]
\textit{Chang, Yi-Jun; Li, Zeyong}, The complexity of distributed approximation of packing and covering Integer linear programs, 32-43 [Zbl 07824308]
\textit{Huang, Shang-En; Su, Hsin-Hao}, \((1-\epsilon)\)-approximate maximum weighted matching in \(\mathrm{poly}(1/\epsilon,\log n)\) time in the distributed and parallel settings, 44-54 [Zbl 07824309]
\textit{Chang, Yi-Jun}, Efficient distributed decomposition and routing algorithms in minor-free networks and their applications, 55-66 [Zbl 07824310]
\textit{Dou, Jinfeng; Götte, Thorsten; Hillebrandt, Henning; Scheideler, Christian; Werthmann, Julian}, Brief announcement: Distributed construction of near-optimal compact routing schemes for planar graphs, 67-70 [Zbl 07824311]
\textit{de Vos, Tijn}, Brief announcement: Minimum cost maximum flow in the CONGEST model, 71-74 [Zbl 07824312]
\textit{Forster, Sebastian; de Vos, Tijn}, Brief announcement: The Laplacian paradigm in deterministic congested clique, 75-78 [Zbl 07824313]
\textit{Chan, David Yu Cheng; Giakkoupis, George; Woelfel, Philipp}, Word-size RMR tradeoffs for recoverable mutual exclusion, 79-89 [Zbl 07824314]
\textit{Castañeda, Armando; Rodríguez, Gilde Valeria}, Asynchronous wait-free runtime verification and enforcement of linearizability, 90-101 [Zbl 07824315]
\textit{Sheffi, Gali; Petrank, Erez}, The ERA theorem for safe memory reclamation, 102-112 [Zbl 07824316]
\textit{Bashari, Benyamin; Jamadi, Ali; Woelfel, Philipp}, Efficient bounded timestamping from standard synchronization primitives, 113-123 [Zbl 07824317]
\textit{Naderibeni, Hossein; Ruppert, Eric}, A wait-free queue with polylogarithmic step complexity, 124-134 [Zbl 07824318]
\textit{Dufoulon, Fabien; Moses, William K.; Pandurangan, Gopal}, Distributed MIS in \(O(\log\log n)\) awake complexity, 135-145 [Zbl 07824319]
\textit{Ghaffari, Mohsen; Portmann, Julian}, Distributed MIS with low energy and time complexities, 146-156 [Zbl 07824320]
\textit{Maus, Yannic; Peltonen, Saku; Uitto, Jara}, Distributed symmetry breaking on power graphs via sparsification, 157-167 [Zbl 07824321]
\textit{Robinson, Peter}, Brief announcement: What can we compute in a single round of the congested clique?, 168-171 [Zbl 07824322]
\textit{Agrawal, Akanksha; Augustine, John; Peleg, David; Ramachandran, Srikkanth}, Brief announcement: Local problems in the SUPPORTED model, 172-175 [Zbl 07824323]
\textit{Di Luna, Giuseppe Antonio; Viglietta, Giovanni}, Brief announcement: Efficient computation in congested anonymous dynamic networks, 176-179 [Zbl 07824324]
\textit{Ghaffari, Mohsen; Trygub, Anton}, A near-optimal deterministic distributed synchronizer, 180-189 [Zbl 07824325]
\textit{Izumi, Taisuke; Emek, Yuval; Wadayama, Tadashi; Masuzawa, Toshimitsu}, Deterministic fault-tolerant connectivity labeling scheme, 190-199 [Zbl 07824326]
\textit{Arapinis, Myrto; Kocsis, Ábel; Lamprou, Nikolaos; Medley, Liam; Zacharias, Thomas}, Universally composable simultaneous broadcast against a dishonest majority and applications, 200-210 [Zbl 07824327]
\textit{Berenbrink, Petra; Cooper, Colin; Gava, Cristina; Marzagão, David Kohan; Mallmann-Trenn, Frederik; Radzik, Tomasz; Rivera, Nicolas}, Distributed averaging in opinion dynamics, 211-221 [Zbl 07824328]
\textit{Zuzic, Goran; Haeupler, Bernhard; Roeyskoe, Antti}, Sparse semi-oblivious routing. Few random paths suffice, 222-232 [Zbl 07824329]
\textit{Giridharan, Neil; Suri-Payer, Florian; Ding, Matthew; Howard, Heidi; Abraham, Ittai; Crooks, Natacha}, BeeGees: stayin' alive in chained BFT, 233-243 [Zbl 07824330]
\textit{Alpturer, Kaya; Halpern, Joseph Y.; van der Meyden, Ron}, Optimal eventual Byzantine agreement protocols with omission failures, 244-252 [Zbl 07824331]
\textit{Wan, Jun; Momose, Atsuki; Ren, Ling; Shi, Elaine; Xiang, Zhuolun}, On the amortized communication complexity of Byzantine broadcast, 253-261 [Zbl 07824332]
\textit{Fischer, Orr; Parter, Merav}, Distributed CONGEST algorithms against mobile adversaries, 262-273 [Zbl 07824333]
\textit{Bazzi, Rida; Tucci-Piergiovanni, Sara}, Brief announcement: Breaking the \(f+1\) barrier: executing payment transactions in parallel with less than \(f+1\) validations, 274-277 [Zbl 07824334]
\textit{Cooper, Colin; Radzik, Tomasz; Shiraga, Takeharu}, Brief announcement: Discrete incremental voting, 278-281 [Zbl 07824335]
\textit{Déprés, Mathilde; Mostéfaoui, Achour; Perrin, Matthieu; Raynal, Michel}, Brief announcement: The MBroadcast abstraction, 282-285 [Zbl 07824336]
\textit{Hajiaghayi, MohammadTaghi; Kowalski, Dariusz Rafal; Olkowski, Jan}, Brief announcement: Improved consensus in quantum networks, 286-289 [Zbl 07824337]
\textit{Davies, Peter}, Uniting general-graph and geometric-based radio networks via independence number parametrization, 290-299 [Zbl 07824338]
\textit{Davies, Peter}, Optimal message-passing with noisy beeps, 300-309 [Zbl 07824339]
\textit{Giakkoupis, George; Ziccardi, Isabella}, Distributed self-stabilizing MIS with few states and weak communication, 310-320 [Zbl 07824340]
\textit{Friedrich, Tobias; Gawendowicz, Hans; Lenzner, Pascal; Zahn, Arthur}, The impact of cooperation in bilateral network creation, 321-331 [Zbl 07824341]
\textit{Civit, Pierre; Gilbert, Seth; Guerraoui, Rachid; Komatovic, Jovan; Vidigueira, Manuel}, On the validity of consensus, 332-343 [Zbl 07824342]
\textit{Chlebus, Bogdan; Kowalski, Dariusz Rafal; Olkowski, Jan}, Deterministic fault-tolerant distributed computing in linear time and communication, 344-354 [Zbl 07824343]
\textit{Kutten, Shay; Robinson, Peter; Tan, Ming Ming; Zhu, Xianbin}, Improved tradeoffs for leader election, 355-365 [Zbl 07824344]
\textit{Jayanti, Prasad; Jayanti, Siddhartha Visveswara; Jayanti, Sucharita}, Brief announcement: Efficient recoverable writable-CAS, 366-369 [Zbl 07824345]
\textit{Tran, Anh; Talmage, Edward}, Brief announcement: Improved, partially-tight multiplicity queue lower bounds, 370-373 [Zbl 07824346]
\textit{Cadambe, Viveck R.; Lyu, Shihang}, Brief announcement: CausalEC: a causally consistent data storage Algorithm based on cross-object erasure coding, 374-377 [Zbl 07824347]Prefacehttps://zbmath.org/1530.680382024-04-15T15:10:58.286558ZFrom the text: This special issue presents a small group of papers presented at the 16th International Conference on Unconventional Computation and Natural Computation (UCNC 2017). The conference was held at the University of Arkansas, in Fayetteville, AR, USA from June 5--9, 2017.Learning with fractional orthogonal kernel classifiers in support vector machines. Theory, algorithms and applicationshttps://zbmath.org/1530.680392024-04-15T15:10:58.286558ZPublisher's description: This book contains select chapters on support vector algorithms from different perspectives, including mathematical background, properties of various kernel functions, and several applications. The main focus of this book is on orthogonal kernel functions, and the properties of the classical kernel functions -- Chebyshev, Legendre, Gegenbauer, and Jacobi -- are reviewed in some chapters. Moreover, the fractional form of these kernel functions is introduced in the same chapters, and for ease of use for these kernel functions, a tutorial on a Python package named ORSVM is presented. The book also exhibits a variety of applications for support vector algorithms, and in addition to the classification, these algorithms along with the introduced kernel functions are utilized for solving ordinary, partial, integro, and fractional differential equations.
On the other hand, nowadays, the real-time and big data applications of support vector algorithms are growing. Consequently, the Compute Unified Device Architecture (CUDA) parallelizing the procedure of support vector algorithms based on orthogonal kernel functions is presented. The book sheds light on how to use support vector algorithms based on orthogonal kernel functions in different situations and gives a significant perspective to all machine learning and scientific machine learning researchers all around the world to utilize fractional orthogonal kernel functions in their pattern recognition or scientific computing problems.
The articles of this volume will be reviewed individually.Mathematical modeling and simulation of systems. Selected papers of 17th international conference, MODS, Chernihiv, Ukraine, November 14--16, 2022https://zbmath.org/1530.680402024-04-15T15:10:58.286558ZPublisher's description: Modern complex multi-domain systems require increased efficiency, reliability, and availability combined with reduced cost. This book contains papers on mathematical modeling and simulation of processes in various areas: ecology and the environment, production and energy, information technology, samples of special-purpose equipment, and cyber-physical systems.
The outcomes presented in the book are useful to specialists involved in the modeling and simulation of real-world system, management and decision-making models, production models, and software products. Scientists have the opportunity to familiarize themselves with the latest research in a variety of solutions proposed by leading scientists and to determine promising directions for solving complex scientific and practical tasks. Chapters of this book contain papers presented at the 17th MODS International Conference, November 14--16, 2022, Chernihiv, Ukraine.
The articles of this volume will not be indexed individually. For the preceding conference see [Zbl 1490.68030].UCNC 2018 special issue editorialhttps://zbmath.org/1530.680412024-04-15T15:10:58.286558ZFrom the text: This special issue contains selected papers from the 17th Unconventional Computation and Natural Computation (UCNC 2018) conference. The conference was held on the campus of the IUT de Fontainebleau at the University of Paris-Est Créteil -- Val de Marne, Fontainebleau, France, June 25--29, 2018.Prefacehttps://zbmath.org/1530.680422024-04-15T15:10:58.286558ZFrom the text: This special issue focuses at research on swarm intelligence algorithms and applications. Presented are selected papers from the 8th/9th International Conference on Swarm Intelligence and the 2nd/3rd International Conference of Data Mining and Big Data (ICSI-DMBD 2017\&2018) which were successfully held in Fukuoka, Japan and Shanghai, China, respectively.Prefacehttps://zbmath.org/1530.680432024-04-15T15:10:58.286558Z"Tan, Ying"https://zbmath.org/authors/?q=ai:tan.ying"Shi (ed.), Yuhui"https://zbmath.org/authors/?q=ai:shi.yuhuiFrom the text: This special issue aims at promoting research on swarm intelligence and its applications by publishing some of the important advances in current research. A number of active researchers responded enthusiastically to our call for contributions. As the outcome of a thorough reviewing process, eight papers were chosen for this special issue.Prefacehttps://zbmath.org/1530.680442024-04-15T15:10:58.286558ZFrom the text: This special issue is based on a collection of selected papers presented at the annual International Conference on Membrane Computing in 2021, both at the European chapter (CMC), as well as at the Asian chapter (ACMC).Distributed computer and communication networks: control, computation, communications. 25th international conference, DCCN 2022, Moscow, Russia, September 26--29, 2022. Revised selected papershttps://zbmath.org/1530.680452024-04-15T15:10:58.286558ZPublisher's description: This book constitutes the refereed proceedings of the 25th International Conference on Distributed Computer and Communication Networks, DCCN 2022, held in Moscow, Russia, in September 2022.
The 27 full papers and 2 short papers included in this book were carefully reviewed and selected from 130 submissions. They were organized in topical sections as follows: Distributed Systems Applications, Computer and Communication Networks, Analytical Modeling of Distributed Systems.
The articles of mathematical interest will be reviewed individually. For the preceding conference see [Zbl 1490.68033].Proceedings of the 35th annual ACM-SIAM symposium on discrete algorithms, SODA 2024, Alexandria, Virginia, January 7--10, 2024https://zbmath.org/1530.680462024-04-15T15:10:58.286558ZThe articles of this volume will be reviewed individually. For the preceding workshop see [Zbl 1507.68020].An ANN-based scalable hashing algorithm for computational clouds with schedulershttps://zbmath.org/1530.680472024-04-15T15:10:58.286558Z"Tchórzewski, Jacek"https://zbmath.org/authors/?q=ai:tchorzewski.jacek"Jakóbik, Agnieszka"https://zbmath.org/authors/?q=ai:jakobik.agnieszka"Iacono, Mauro"https://zbmath.org/authors/?q=ai:iacono.mauroSummary: The significant benefits of cloud computing (CC) resulted in an explosion of their usage in the last several years. From the security perspective, CC systems have to offer solutions that fulfil international standards and regulations. In this paper, we propose a model for a hash function having a scalable output. The model is based on an artificial neural network trained to mimic the chaotic behaviour of the Mackey-Glass time series. This hashing method can be used for data integrity checking and digital signature generation. It enables constructing cryptographic services according to the user requirements and time constraints due to scalable output. Extensive simulation experiments are conduced to prove its cryptographic strength, including three tests: a bit prediction test, a series test, and a Hamming distance test. Additionally, flexible hashing function performance tests are run using the CloudSim simulator mimicking a cloud with a global scheduler to investigate the possibility of idle time consumption of virtual machines that may be spent on the scalable hashing protocol. The results obtained show that the proposed hashing method can be used for building light cryptographic protocols. It also enables incorporating the integrity checking algorithm that lowers the idle time of virtual machines during batch task processing.Distribution of a heterogeneous set of resources in multiprocessor schedulinghttps://zbmath.org/1530.680482024-04-15T15:10:58.286558Z"Furugyan, M. G."https://zbmath.org/authors/?q=ai:furugyan.m-g(no abstract)Using solvable real time classes for jitter-minimized planninghttps://zbmath.org/1530.680492024-04-15T15:10:58.286558Z"Gruzlikov, A. M."https://zbmath.org/authors/?q=ai:gruzlikov.alexander-m"Kolesov, N. V."https://zbmath.org/authors/?q=ai:kolesov.nikolai-vSummary: An approach to scheduling a computational process in distributed real-time systems with minimization of the jitter at the moment of starting or completing a task from period to period is considered. The approach is based on the concept of a solvable class of systems for which there are optimal scheduling algorithms of polynomial complexity.Adversarial formal semantics of attack trees and related problemshttps://zbmath.org/1530.680502024-04-15T15:10:58.286558Z"Brihaye, Thomas"https://zbmath.org/authors/?q=ai:brihaye.thomas"Pinchinat, Sophie"https://zbmath.org/authors/?q=ai:pinchinat.sophie"Terefenko, Alexandre"https://zbmath.org/authors/?q=ai:terefenko.alexandreSummary: Security is a subject of increasing attention in our actual society in order to protect critical resources from information disclosure, theft or damage. The informal model of attack trees introduced by Schneier, and widespread in the industry, is advocated in the 2008 NATO report to govern the evaluation of the threat in risk analysis. Attack-defense trees have since been the subject of many theoretical works addressing different formal approaches.
In 2017, \textit{M. Audinot} et al. [Lect. Notes Comput. Sci. 10492, 83--102 (2017; Zbl 1496.68054)] introduced a path semantics over a transition system for attack trees. Inspired by the later, we propose a two-player interpretation of the attack-tree formalism. To do so, we replace transition systems by concurrent game arenas and our associated semantics consist of strategies. We then show that the emptiness problem, known to be NP-complete for the path semantics, is now \textsc{Pspace}-complete. Additionally, we show that the membership problem is \textsc{coNP}-complete for our two-player interpretation while it collapses to P in the path semantics.
For the entire collection see [Zbl 1522.68028].Deep reinforcement learning for \textsf{FlipIt} security gamehttps://zbmath.org/1530.680512024-04-15T15:10:58.286558Z"Greige, Laura"https://zbmath.org/authors/?q=ai:greige.laura"Chin, Peter"https://zbmath.org/authors/?q=ai:chin.peterFor the entire collection see [Zbl 1492.94005].Optimized deep stacked autoencoder for ransomware detection using blockchain networkhttps://zbmath.org/1530.680522024-04-15T15:10:58.286558Z"Nalinipriya, G."https://zbmath.org/authors/?q=ai:nalinipriya.g"Maram, Balajee"https://zbmath.org/authors/?q=ai:maram.balajee"Vidyadhari, Ch."https://zbmath.org/authors/?q=ai:vidyadhari.ch"Cristin, R."https://zbmath.org/authors/?q=ai:cristin.renato(no abstract)Reactive answer set programminghttps://zbmath.org/1530.680532024-04-15T15:10:58.286558Z"Broda, Krysia"https://zbmath.org/authors/?q=ai:broda.krysia-b"Sadri, Fariba"https://zbmath.org/authors/?q=ai:sadri.fariba"Butler, Stephen"https://zbmath.org/authors/?q=ai:butler.stephenSummary: Logic Production System (LPS) is a logic-based framework for modelling reactive behaviour. Based on abductive logic programming, it combines reactive rules with logic programs, a database and a causal theory that specifies transitions between the states of the database. This paper proposes a systematic mapping of the Kernel of this framework (called KELPS) into an answer set program (ASP). For this purpose a new variant of KELPS with finite models, called \(n\)-distance KELPS, is introduced. A formal definition of the mapping from this \(n\)-distance KELPS to ASP is given and proven sound and complete. The Answer Set Programming paradigm allows to capture additional behaviours to the basic reactivity of KELPS, in particular proactive, pre-emptive and prospective behaviours. These are all discussed and illustrated with examples. Then a hybrid framework is proposed that integrates KELPS and ASP, allowing to combine the strengths of both paradigms.On correctness and completeness of an \(n\) queens programhttps://zbmath.org/1530.680542024-04-15T15:10:58.286558Z"Drabent, Włodzimierz"https://zbmath.org/authors/?q=ai:drabent.wlodzimierzSummary: Thom Frühwirth presented a short, elegant, and efficient Prolog program for the \(n\) queens problem. However, the program may be seen as rather tricky and one may not be convinced about its correctness. This paper explains the program in a declarative way and provides proofs of its correctness and completeness. The specification and the proofs are declarative, that is they abstract from any operational semantics. The specification is approximate, it is unnecessary to describe the program's semantics exactly. Despite the program works on non-ground terms, this work employs the standard semantics, based on logical consequence and Herbrand interpretations. Another purpose of the paper is to present an example of precise declarative reasoning about the semantics of a logic program.Matching and generalization modulo proximity and tolerance relationshttps://zbmath.org/1530.680552024-04-15T15:10:58.286558Z"Kutsia, Temur"https://zbmath.org/authors/?q=ai:kutsia.temur"Pau, Cleo"https://zbmath.org/authors/?q=ai:pau.cleoSummary: Proximity relations are fuzzy binary relations satisfying reflexivity and symmetry properties. Tolerance, which is a reflexive and symmetric (and not necessarily transitive) relation, can be also seen as a crisp version of proximity. We discuss two fundamental symbolic computation problems for proximity and tolerance relations: matching and anti-unification, present algorithms for solving them, and study properties of those algorithms.
For the entire collection see [Zbl 1494.03010].Strong equivalence and program structure in arguing essential equivalence between logic programshttps://zbmath.org/1530.680562024-04-15T15:10:58.286558Z"Lierler, Yuliya"https://zbmath.org/authors/?q=ai:lierler.yuliyaSummary: Answer set programming is a prominent declarative programming paradigm used in formulating combinatorial search problems and implementing different knowledge representation formalisms. Frequently, several related and yet substantially different answer set programs exist for a given problem. Sometimes these encodings may display significantly different performance. Uncovering \textit{precise formal} links between these programs is often important and yet far from trivial. This paper presents formal results carefully relating a number of interesting program rewritings. It also provides the proof of correctness of system projector concerned with automatic program rewritings for the sake of efficiency.On signings and the well-founded semanticshttps://zbmath.org/1530.680572024-04-15T15:10:58.286558Z"Maher, Michael J."https://zbmath.org/authors/?q=ai:maher.michael-jSummary: In this note, we use Kunen's notion of a signing to establish two theorems about the well-founded semantics of logic programs, in the case where we are interested in only (say) the positive literals of a predicate \(p\) that are consequences of the program. The first theorem identifies a class of programs for which the well-founded and Fitting semantics coincide for the positive part of \(p\). The second theorem shows that if a program has a signing, then computing the positive part of \(p\) under the well-founded semantics requires the computation of only one part of each predicate. This theorem suggests an analysis for query answering under the well-founded semantics. In the process of proving these results, we use an alternative formulation of the well-founded semantics of logic programs, which might be of independent interest.Solution enumeration by optimality in answer set programminghttps://zbmath.org/1530.680582024-04-15T15:10:58.286558Z"Pajunen, Jukka"https://zbmath.org/authors/?q=ai:pajunen.jukka"Janhunen, Tomi"https://zbmath.org/authors/?q=ai:janhunen.tomiSummary: Given a combinatorial search problem, it may be highly useful to enumerate its (all) solutions besides just finding one solution, or showing that none exists. The same can be stated about optimal solutions if an objective function is provided. This work goes beyond the bare enumeration of optimal solutions and addresses the computational task of solution enumeration by optimality (SEO). This task is studied in the context of answer set programming (ASP) where (optimal) solutions of a problem are captured with the answer sets of a logic program encoding the problem. Existing answer set solvers already support the enumeration of all (optimal) answer sets. However, in this work, we generalize the enumeration of optimal answer sets beyond strictly optimal ones, giving rise to the idea of answer set enumeration in the order of optimality (ASEO). This approach is applicable up to the best \(k\) answer sets or in an unlimited setting, which amounts to a process of sorting answer sets based on the objective function. As the main contribution of this work, we present the first general algorithms for the aforementioned tasks of answer set enumeration. Moreover, we illustrate the potential use cases of ASEO. First, we study how efficiently access to the next-best solutions can be achieved in a number of optimization problems that have been formalized and solved in ASP. Second, we show that ASEO provides us with an effective sampling technique for Bayesian networks.\textsf{VeriFly}: on-the-fly assertion checking via incrementalityhttps://zbmath.org/1530.680592024-04-15T15:10:58.286558Z"Sanchez-Ordaz, Miguel A."https://zbmath.org/authors/?q=ai:sanchez-ordaz.miguel-a"Garcia-Contreras, Isabel"https://zbmath.org/authors/?q=ai:garcia-contreras.isabel"Perez, Victor"https://zbmath.org/authors/?q=ai:perez.victor-m|perez.victor-e"Morales, José F."https://zbmath.org/authors/?q=ai:morales.jose-francisco"Lopez-Garcia, Pedro"https://zbmath.org/authors/?q=ai:lopez-garcia.pedro"Hermenegildo, Manuel V."https://zbmath.org/authors/?q=ai:hermenegildo.manuel-vSummary: Assertion checking is an invaluable programmer's tool for finding many classes of errors or verifying their absence in dynamic languages such as Prolog. For Prolog programmers, this means being able to have relevant properties, such as modes, types, determinacy, nonfailure, sharing, constraints, and cost, checked and errors flagged without having to actually run the program. Such global static analysis tools are arguably most useful the earlier they are used in the software development cycle, and fast response times are essential for interactive use. Triggering a full and precise semantic analysis of a software project every time a change is made can be prohibitively expensive. This is specially the case when complex properties need to be inferred for large, realistic code bases. In our static analysis and verification framework, this challenge is addressed through a combination of modular and incremental (context- and path-sensitive) analysis that is responsive to program edits, at different levels of granularity. In this tool paper, we present how the combination of this framework within an integrated development environment (IDE) takes advantage of such incrementality to achieve a high level of reactivity when reflecting analysis and verification results back as colorings and tooltips directly on the program text -- the tool's \textsf{VeriFly} mode. The concrete implementation that we describe is Emacs-based and reuses in part off-the-shelf ``on-the-fly'' \textit{syntax} checking facilities (\textsf{flycheck}). We believe that similar extensions are also reproducible with low effort in other mature development environments. Our initial experience with the tool shows quite promising results, with low latency times that provide early, continuous, and precise assertion checking and other semantic feedback to programmers during the development process. The tool supports Prolog natively, as well as other languages by semantic transformation into Horn clauses.FOLASP: \(\mathrm{FO}(\cdot)\) as input language for answer set solvershttps://zbmath.org/1530.680602024-04-15T15:10:58.286558Z"Van Dessel, Kylian"https://zbmath.org/authors/?q=ai:van-dessel.kylian"Devriendt, Jo"https://zbmath.org/authors/?q=ai:devriendt.jo"Vennekens, Joost"https://zbmath.org/authors/?q=ai:vennekens.joostSummary: Technological progress in Answer Set Programming (ASP) has been stimulated by the use of common standards, such as the ASP-Core-2 language. While ASP has its roots in nonmonotonic reasoning, efforts have also been made to reconcile ASP with classical first-order (FO) logic. This has resulted in the development of \(\mathrm{FO}(\cdot)\), an expressive extension of FO, which allows ASP-like problem solving in a purely classical setting. This language may be more accessible to domain experts already familiar with FO and may be easier to combine with other formalisms that are based on classical logic. It is supported by the IDP inference system, which has successfully competed in a number of ASP competitions. Here, however, technological progress has been hampered by the limited number of systems that are available for \(\mathrm{FO}(\cdot)\). In this paper, we aim to address this gap by means of a translation tool that transforms an \(\mathrm{FO}(\cdot)\) specification into ASP-Core-2, thereby allowing ASP-Core-2 solvers to be used as solvers for \(\mathrm{FO}(\cdot)\) as well. We present experimental results to show that the resulting combination of our translation with an off-the-shelf ASP solver is competitive with the IDP system as a way of solving problems formulated in \(\mathrm{FO}(\cdot)\).An asymptotic analysis of probabilistic logic programming, with implications for expressing projective families of distributionshttps://zbmath.org/1530.680612024-04-15T15:10:58.286558Z"Weitkämper, Felix Q."https://zbmath.org/authors/?q=ai:weitkamper.felix-qSummary: Probabilistic logic programming is a major part of statistical relational artificial intelligence, where approaches from logic and probability are brought together to reason about and learn from relational domains in a setting of uncertainty. However, the behaviour of statistical relational representations across variable domain sizes is complex, and scaling inference and learning to large domains remains a significant challenge. In recent years, connections have emerged between domain size dependence, lifted inference and learning from sampled subpopulations. The asymptotic behaviour of statistical relational representations has come under scrutiny, and projectivity was investigated as the strongest form of domain size dependence, in which query marginals are completely independent of the domain size. In this contribution we show that every probabilistic logic program under the distribution semantics is asymptotically equivalent to an acyclic probabilistic logic program consisting only of determinate clauses over probabilistic facts. We conclude that every probabilistic logic program inducing a projective family of distributions is in fact everywhere equivalent to a program from this fragment, and we investigate the consequences for the projective families of distributions expressible by probabilistic logic programs.A user's friendly syntax to define recursive functions as typed \(\lambda \)-termshttps://zbmath.org/1530.680622024-04-15T15:10:58.286558Z"Manoury, Pascal"https://zbmath.org/authors/?q=ai:manoury.pascalSummary: This paper discusses the problem of translating a (recursive) function definition expressed in a ML like syntax into a typed \(\lambda \)-term. In this paper, we recall how termination proofs can be solutions of the investigated problem. Then we recall how the method of [\textit{P. Manoury} and \textit{M. Simonot}, Theor. Comput. Sci. 135, No. 2, 319--343 (1994; Zbl 0829.68031)] deals with the problem of searching termination proofs. Finally, we discuss the questions raised by the adaptation of our method to the Coq proof assistant.
For the entire collection see [Zbl 0866.00037].Formalization of a \(\lambda \)-calculus with explicit substitutions in Coqhttps://zbmath.org/1530.680632024-04-15T15:10:58.286558Z"Saïbi, Amokrane"https://zbmath.org/authors/?q=ai:saibi.amokraneSummary: We present a formalization of the \(\lambda \sigma_\Uparrow \)-calculus [\textit{G. Huet}, J. Assoc. Comput. Mach. 27, 797--821 (1980; Zbl 0458.68007)] in the Coq V5.8 system [\textit{G. Dowek} et al., The Coq proof assistant user's guide, version 5.8. Rapport technique INRIA 154 (1993)]. The principal axiomatized result is the confluence of this calculus. Furthermore we propose a uniform encoding for many-sorted first order term rewriting systems, on which we study the local confluence by critical pairs analysis.
For the entire collection see [Zbl 0866.00037].Parameterized cast calculi and reusable meta-theory for gradually typed lambda calculihttps://zbmath.org/1530.680642024-04-15T15:10:58.286558Z"Siek, Jeremy G."https://zbmath.org/authors/?q=ai:siek.jeremy-g"Chen, Tianyu"https://zbmath.org/authors/?q=ai:chen.tianyuSummary: The research on gradual typing has led to many variations on the Gradually Typed Lambda Calculus (GTLC) of \textit{J. G.
Siek} and \textit{W. Taha} [``Gradual typing for functional languages'', Scheme 2006, 81--92 (2006), \url{http://scheme2006.cs.uchicago.edu/13-siek.pdf}; Gradual typing for objects: Isabelle formalization. Techn. Rep., Univ. of Colorado Boulder (2006), \url{https://scholar.colorado.edu/concern/reports/dv13zv03g}; Gradual typing: Isabelle/Isar formalization. Techn. Rep., Rice Univ. Houston (2006), \url{https://hdl.handle.net/1911/96348}] and its underlying cast calculus. For example, \textit{P. Wadler} and \textit{R. B. Findler} [Lect. Notes Comput. Sci. 5502, 1--16 (2009; Zbl 1234.68063)] added blame tracking, \textit{J. Siek} et al. [Lect. Notes Comput. Sci. 5502, 17--31 (2009; Zbl 1234.68060)] investigated alternate cast evaluation strategies, and \textit{D. Herman} et al. [High.-Order Symb. Comput. 23, No. 2, 167--189 (2010; Zbl 1232.68025)] replaced casts with coercions for space efficiency. The meta-theory for the GTLC has also expanded beyond type safety to include blame safety [\textit{S. Tobin-Hochstadt} and \textit{M. Felleisen}, ``Interlanguage migration: from scripts to programs'', OOPSLA 2006, 964--974 (2006; \url{doi:10.1145/1176617.1176755})], space consumption
[Herman et al., loc. cit.], and the gradual guarantees [\textit{J. G. Siek} et al., ``Blame and coercion: together again for the first time'', PLDI 2015, 425--435 (2015; \url{doi:10.1145/2737924.2737968}); ``Refined criteria for gradual typing'', SNAPL 2015, 274--293 (2015; \url{doi:10.4230/LIPIcs.SNAPL.2015.274}); Lect. Notes Comput. Sci. 9032, 432--456 (2015; Zbl 1335.68069)]. These results have been proven for some variations of the GTLC but not others. Furthermore, researchers continue to develop variations on the GTLC, but establishing all of the meta-theory for new variations is time-consuming. This article identifies abstractions that capture similarities between many cast calculi in the form of two parameterized cast calculi, one for the purposes of language specification and the other to guide space-efficient implementations. The article then develops reusable meta-theory for these two calculi, proving type safety, blame safety, the gradual guarantees, and space consumption. Finally, the article instantiates this meta-theory for eight cast calculi including five from the literature and three new calculi. All of these definitions and theorems, including the two parameterized calculi, the reusable meta-theory, and the eight instantiations, are mechanized in Agda making extensive use of module parameters and dependent records to define the abstractions.Transformation-enabled precondition inferencehttps://zbmath.org/1530.680652024-04-15T15:10:58.286558Z"Kafle, Bishoksan"https://zbmath.org/authors/?q=ai:kafle.bishoksan"Gange, Graeme"https://zbmath.org/authors/?q=ai:gange.graeme"Stuckey, Peter J."https://zbmath.org/authors/?q=ai:stuckey.peter-j"Schachte, Peter"https://zbmath.org/authors/?q=ai:schachte.peter"Søndergaard, Harald"https://zbmath.org/authors/?q=ai:sondergaard.haraldSummary: Precondition inference is a non-trivial problem with important applications in program analysis and verification. We present a novel iterative method for automatically deriving preconditions for the safety and unsafety of programs. Each iteration maintains over-approximations of the set of \textit{safe} and \textit{unsafe initial} states, which are used to partition the program's \textit{initial} states into those known to be \textit{safe}, known to be \textit{unsafe} and \textit{unknown}. We then construct revised programs with those \textit{unknown} initial states and iterate the procedure until the approximations are disjoint or some termination criteria are met. An experimental evaluation of the method on a set of software verification benchmarks shows that it can infer precise preconditions (sometimes optimal) that are not possible using previous methods.Closest-pair queries and minimum-weight queries are equivalent for squareshttps://zbmath.org/1530.680662024-04-15T15:10:58.286558Z"Kazi, Abrar"https://zbmath.org/authors/?q=ai:kazi.abrar"Smid, Michiel"https://zbmath.org/authors/?q=ai:smid.michiel-h-mSummary: Let \(S\) be a set of \(n\) weighted points in the plane and let \(R\) be a query range in the plane. In the range closest pair problem, we want to report the closest pair in the set \(R \cap S\). In the range minimum weight problem, we want to report the minimum weight of any point in the set \(R \cap S\). We show that these two query problems are equivalent for query ranges that are squares, for data structures having \(\Omega(\log n)\) query times. As a result, we obtain new data structures for range closest pair queries with squares.Exploiting database management systems and treewidth for countinghttps://zbmath.org/1530.680672024-04-15T15:10:58.286558Z"Fichte, Johannes K."https://zbmath.org/authors/?q=ai:fichte.johannes-klaus"Hecher, Markus"https://zbmath.org/authors/?q=ai:hecher.markus"Thier, Patrick"https://zbmath.org/authors/?q=ai:thier.patrick"Woltran, Stefan"https://zbmath.org/authors/?q=ai:woltran.stefanSummary: Bounded treewidth is one of the most cited combinatorial invariants in the literature. It was also applied for solving several counting problems efficiently. A canonical counting problem is \#\textsc{Sat}, which asks to count the satisfying assignments of a Boolean formula. Recent work shows that benchmarking instances for \#\textsc{Sat} often have reasonably small treewidth. This paper deals with counting problems for instances of small treewidth. We introduce a general framework to solve counting questions based on state-of-the-art database management systems (DBMSs). Our framework takes explicitly advantage of small treewidth by solving instances using dynamic programming (DP) on tree decompositions (TD). Therefore, we implement the concept of DP into a DBMS (PostgreSQL), since DP algorithms are already often given in terms of table manipulations in theory. This allows for elegant specifications of DP algorithms and the use of SQL to manipulate records and tables, which gives us a natural approach to bring DP algorithms into practice. To the best of our knowledge, we present the first approach to employ a DBMS for algorithms on TDs. A key advantage of our approach is that DBMSs naturally allow for dealing with huge tables with a limited amount of main memory (RAM).Inapplicability of differential fault attacks against cellular automata based lightweight authenticated cipherhttps://zbmath.org/1530.680682024-04-15T15:10:58.286558Z"Ambili, K. N."https://zbmath.org/authors/?q=ai:ambili.k-n"Jose, Jimmy"https://zbmath.org/authors/?q=ai:jose.jimmy(no abstract)Reinforcing lightweight authenticated encryption schemes against statistical ineffective fault attackhttps://zbmath.org/1530.680692024-04-15T15:10:58.286558Z"Ambili, K. N."https://zbmath.org/authors/?q=ai:ambili.k-n"Jose, Jimmy"https://zbmath.org/authors/?q=ai:jose.jimmy(no abstract)EnCash: an authenticated encryption scheme using cellular automatahttps://zbmath.org/1530.680702024-04-15T15:10:58.286558Z"Banerjee, Tapadyoti"https://zbmath.org/authors/?q=ai:banerjee.tapadyoti"Roy Chowdhury, Dipanwita"https://zbmath.org/authors/?q=ai:chowdhury.dipanwita-roy|roychowdhury.dipanwita(no abstract)A new symmetrical cryptosystem based cellular automata and chaotic map functionhttps://zbmath.org/1530.680712024-04-15T15:10:58.286558Z"Boudali, Asmaa"https://zbmath.org/authors/?q=ai:boudali.asmaa"Said, Naima Hadj"https://zbmath.org/authors/?q=ai:said.naima-hadj"Ali-Pacha, Adda"https://zbmath.org/authors/?q=ai:ali-pacha.adda(no abstract)Fault resistant Trivium-like stream cipher using higher radii cellular automatahttps://zbmath.org/1530.680722024-04-15T15:10:58.286558Z"John, Anita"https://zbmath.org/authors/?q=ai:john.anita"Mineesh Reddy, Sai Kallupalle"https://zbmath.org/authors/?q=ai:mineesh-reddy.sai-kallupalle"Jose, Jimmy"https://zbmath.org/authors/?q=ai:jose.jimmy(no abstract)Waiting for the rapture: what can we do with computers to (hopefully) witness the emergence of life?https://zbmath.org/1530.680732024-04-15T15:10:58.286558Z"Toffoli, Tommaso"https://zbmath.org/authors/?q=ai:toffoli.tommasoSummary: Hadn't this question already been answered? We all know about computation-universal Turing Machines. And we know that any such machine can simulate a space -- time dynamics not unlike von Neumann's cellular automaton (CA), which is computation- and construction-universal and among other things can play host to self-replicating machines. And that self-replication sprinkled with a bit of randomness should inexorably lead to descent with variation, competition, and thence to evolution and all that. ``So what?'' Enrico Fermi would have asked, ``Where is your emergent life?'' (and note that our understanding of both natural and artificial life has much advanced in the 50 years since). It turns out that life is by its very nature a marginal, fragile, and ephemeral kind of phenomenon. For a substrate or a ``culture medium'' to be able to support the emergence from scratch of a lifelike lineage, computation- and construction-universality are necessary -- but by no means sufficient! Paraphrasing Fermi, what automata that you know -- including von Neumann's CA and Conway's very game of Life -- have managed so far to ``capture for us on film'' the \textit{origin} of some kind of life? What questions, then, should we ask of a prospective medium -- be it a Turing machine, a CA, or some other kind of automaton -- that will best probe its capabilities to originate (as well as sustain) some form of life, and which will provide us with a \textit{sense of direction} to help us more quickly converge in this quest.Variants of P systems with activation and blocking of ruleshttps://zbmath.org/1530.680742024-04-15T15:10:58.286558Z"Alhazov, Artiom"https://zbmath.org/authors/?q=ai:alhazov.artiom"Freund, Rudolf"https://zbmath.org/authors/?q=ai:freund.rudolf"Ivanov, Sergiu"https://zbmath.org/authors/?q=ai:ivanov.sergiuSummary: We introduce new possibilities to control the application of rules based on the preceding applications, which can be defined in a general way for (hierarchical) P systems and the main known derivation modes. Computational completeness can be obtained even with non-cooperative rules and using both activation and blocking of rules, especially for the set modes of derivation, when allowing derivation steps with no rules being applied. When we allow the application of rules to influence the application of rules in previous derivation steps, applying a non-conservative semantics for what we consider to be a valid infinite derivation, we can even ``go beyond Turing''.Solving subset sum by spiking neural P systems with astrocytes producing calciumhttps://zbmath.org/1530.680752024-04-15T15:10:58.286558Z"Aman, Bogdan"https://zbmath.org/authors/?q=ai:aman.bogdan(no abstract)On the power of boundary rule application in membrane computinghttps://zbmath.org/1530.680762024-04-15T15:10:58.286558Z"Battyányi, Péter"https://zbmath.org/authors/?q=ai:battyanyi.peter(no abstract)Conjugate word blending: formal model and experimental implementation by XPCRhttps://zbmath.org/1530.680772024-04-15T15:10:58.286558Z"Bellamoli, Francesco"https://zbmath.org/authors/?q=ai:bellamoli.francesco"Franco, Giuditta"https://zbmath.org/authors/?q=ai:franco.giuditta"Kari, Lila"https://zbmath.org/authors/?q=ai:kari.lila"Lampis, Silvia"https://zbmath.org/authors/?q=ai:lampis.silvia"Ng, Timothy"https://zbmath.org/authors/?q=ai:ng.timothy"Wang, Zihao"https://zbmath.org/authors/?q=ai:wang.zihao.1Summary: This paper introduces conjugate word blending as a formal model of molecular processes that occur during a DNA experimental protocol called cross-pairing Polymerase Chain Reaction (XPCR). We analyze this formal word and language operation from a computational viewpoint, by investigating closure properties of four Chomsky language families under it. We also report the molecular biology wet lab experiments based on XPCR amplification of gene sequences, which led to the notion of conjugate word blending.A membrane computing framework for self-reconfigurable robotshttps://zbmath.org/1530.680782024-04-15T15:10:58.286558Z"Bie, Dongyang"https://zbmath.org/authors/?q=ai:bie.dongyang"Gutiérrez-Naranjo, Miguel A."https://zbmath.org/authors/?q=ai:gutierrez-naranjo.miguel-a"Zhao, Jie"https://zbmath.org/authors/?q=ai:zhao.jie.1"Zhu, Yanhe"https://zbmath.org/authors/?q=ai:zhu.yanheSummary: Self-reconfigurable robots are built by modules which can move in relationship to each other, which allows the robot to change its physical form. Finding a sequence of module moves that reconfigures the robot from the initial configuration to the goal configuration is a hard task and many control algorithms have been proposed. In this paper, we present a novel method which combines a cluster-flow locomotion based on cellular automata together with a decentralized local representation of the spatial geometry based on membrane computing ideas. This new approach has been tested with computer simulations and real-world experiments performed with modular self-reconfigurable robots and represents a new point of view with respect other control methods found in the literature.Computing with chemical reaction networks: a tutorialhttps://zbmath.org/1530.680792024-04-15T15:10:58.286558Z"Brijder, Robert"https://zbmath.org/authors/?q=ai:brijder.robertSummary: Chemical reaction networks (CRNs) model the behavior of chemical reactions in well-mixed solutions and they can be designed to perform computations. In this tutorial we give an overview of various computational models for CRNs. Moreover, we discuss a method to implement arbitrary (abstract) CRNs in a test tube using DNA. Finally, we discuss relationships between CRNs and other models of computation.DNAQL: a query language for DNA sticker complexeshttps://zbmath.org/1530.680802024-04-15T15:10:58.286558Z"Brijder, Robert"https://zbmath.org/authors/?q=ai:brijder.robert"Gillis, Joris J. M."https://zbmath.org/authors/?q=ai:gillis.joris-j-m"Van den Bussche, Jan"https://zbmath.org/authors/?q=ai:van-den-bussche.jan(no abstract)From electric circuits to chemical networkshttps://zbmath.org/1530.680812024-04-15T15:10:58.286558Z"Cardelli, Luca"https://zbmath.org/authors/?q=ai:cardelli.luca"Tribastone, Mirco"https://zbmath.org/authors/?q=ai:tribastone.mirco"Tschaikowski, Max"https://zbmath.org/authors/?q=ai:tschaikowski.maxSummary: Electric circuits manipulate electric charge and magnetic flux via a small set of discrete components to implement useful functionality over continuous time-varying signals represented by currents and voltages. Much of the same functionality is useful to biological organisms, where it is implemented by a completely different set of discrete components (typically proteins) and signal representations (typically via concentrations). We describe how to take a linear electric circuit and systematically convert it to a chemical reaction network of the same functionality, as a dynamical system. Both the structure and the components of the electric circuit are dissolved in the process, but the resulting chemical network is intelligible. This approach provides access to a large library of well-studied devices, from analog electronics, whose chemical network realization can be compared to natural biochemical networks, or used to engineer synthetic biochemical networks.Optimal staged self-assembly of linear assemblieshttps://zbmath.org/1530.680822024-04-15T15:10:58.286558Z"Chalk, Cameron"https://zbmath.org/authors/?q=ai:chalk.cameron-t"Martinez, Eric"https://zbmath.org/authors/?q=ai:martinez.eric"Schweller, Robert"https://zbmath.org/authors/?q=ai:schweller.robert-t"Vega, Luis"https://zbmath.org/authors/?q=ai:vega.luis-manuel"Winslow, Andrew"https://zbmath.org/authors/?q=ai:winslow.andrew"Wylie, Tim"https://zbmath.org/authors/?q=ai:wylie.timSummary: We analyze the complexity of building linear assemblies, sets of linear assemblies, and \({\mathcal{O}}(1)\)-scale general shapes in the staged tile assembly model. For systems with at most \(b\) bins and \(t\) tile types, we prove that the minimum number of stages to uniquely assemble a \(1 \times n\) line is \(\varTheta (\log_t{n} + \log_b{\frac{n}{t}} + 1)\). Generalizing to \({\mathcal{O}}(1) \times n\) lines, we prove the minimum number of stages is \({\mathcal{O}}(\frac{\log{n} - tb - t\log t}{b^2} + \frac{\log \log b}{\log t})\) and \(\varOmega (\frac{\log{n} - tb - t\log t}{b^2})\). We also obtain similar upper and lower bounds in a model permitting \textit{flexible glues} using non-diagonal glue functions. Next, we consider assembling sets of lines and general shapes using \(t = {\mathcal{O}}(1)\) tile types. We prove that the minimum number of stages needed to assemble a set of \(k\) lines of size at most \({\mathcal{O}}(1) \times n\) is \({\mathcal{O}}(\frac{k\log n}{b^2}+\frac{k\sqrt{\log n}}{b}+\log \log n)\) and \(\varOmega (\frac{k\log n}{b^2})\). In the case that \(b = \mathcal{O}(\sqrt{k})\), the minimum number of stages is \(\varTheta (\log{n})\). The upper bound in this special case is then used to assemble ``hefty'' shapes of at least logarithmic edge-length-to-edge-count ratio at \(\mathcal{O}(1)\)-scale using \(\mathcal{O}(\sqrt{k})\) bins and optimal \(\mathcal{O}(\log{n})\) stages.About reversibility in sP colonies and reaction systemshttps://zbmath.org/1530.680832024-04-15T15:10:58.286558Z"Cienciala, Ludek"https://zbmath.org/authors/?q=ai:cienciala.ludek"Ciencialová, Lucie"https://zbmath.org/authors/?q=ai:ciencialova.lucie"Csuhaj-Varjú, Erzsébet"https://zbmath.org/authors/?q=ai:csuhaj-varju.erzsebetSummary: In this paper, we study reversibility in sP colonies and in reaction systems. sP colony is a bio-inspired computational model formed from an environment and a finite set of agents. The current state of the environment is represented by a finite set of objects and the current state of the agent is given by a finite multiset of objects. By execution of a program from a set of programs associated with the agent, the agent can change the objects in its own state and possibly in the environment, too. Reaction systems are a bio-inspired computational model where reactants are transformed into products only if some inhibitors are not present. We define sP colonies without input influence and prove that to any reversible sP colony of such type an inverse sP colony can be constructed that performs inverse computation. In the second part of the paper, we show that the concept of a reversible reaction system and the notion of an inverse reaction system can be defined in a similar way, and partially reversible reaction systems can simulate reversible logic gates and reversible Turing machines.Spiking neural P systems and their semantics in Haskellhttps://zbmath.org/1530.680842024-04-15T15:10:58.286558Z"Ciobanu, Gabriel"https://zbmath.org/authors/?q=ai:ciobanu.gabriel"Todoran, Eneia Nicolae"https://zbmath.org/authors/?q=ai:todoran.eneia-nicolaeSummary: We use the functional programming language Haskell to design semantic interpreters for the spiking neural P systems. Haskell provides an appropriate support for implementing the denotational semantics of a concurrent language inspired by the spiking neural P systems. This language and its semantics describe properly the structure and behaviour of the spiking neural P systems. The semantic interpreters capture accurately the nondeterministic behaviour, the time delays between firings and spikings, and the synchronization specific to spiking neural P systems.Approximate majority analyses using tri-molecular chemical reaction networkshttps://zbmath.org/1530.680852024-04-15T15:10:58.286558Z"Condon, Anne"https://zbmath.org/authors/?q=ai:condon.anne-e"Hajiaghayi, Monir"https://zbmath.org/authors/?q=ai:hajiaghayi.monir"Kirkpatrick, David"https://zbmath.org/authors/?q=ai:kirkpatrick.david-g"Maňuch, Ján"https://zbmath.org/authors/?q=ai:manuch.janSummary: Approximate Majority is a well-studied problem in the context of chemical reaction networks (CRNs) and their close relatives, population protocols: Given a mixture of two types of species with an initial gap between their counts, a CRN computation must reach consensus on the majority species. Angluin, Aspnes, and Eisenstat proposed a simple population protocol for Approximate Majority and proved correctness and \(O(\log n)\) time efficiency with high probability, given an initial gap of size \(\omega (\sqrt{n}\log n)\) when the total molecular count in the mixture is \(n\). Motivated by their intriguing but complex proof, we provide a new analysis of several CRNs for Approximate Majority, starting with a very simple tri-molecular protocol with just two reactions and two species. We obtain simple analyses of three bi-molecular protocols, including that of Angluin et al., by showing how they emulate the tri-molecular protocol. Our results improve on those of Angluin et al. in that they hold even with an initial gap of \(\varOmega (\sqrt{n \log n})\). We prove that our tri-molecular CRN is robust even when there is some uncertainty in the reaction rates, when some molecules are Byzantine (i.e., adversarial), or when activation of molecules is triggered by epidemic. We also analyse a natural variant of our tri-molecular protocol for the more general problem of multi-valued consensus. Our analysis approach, which leverages the simplicity of a tri-molecular CRN to ultimately reason about these many variants, may be useful in analysing other CRNs too.Spiking neural networks modelled as timed automata: with parameter learninghttps://zbmath.org/1530.680862024-04-15T15:10:58.286558Z"De Maria, Elisabetta"https://zbmath.org/authors/?q=ai:de-maria.elisabetta"Di Giusto, Cinzia"https://zbmath.org/authors/?q=ai:di-giusto.cinzia"Laversa, Laetitia"https://zbmath.org/authors/?q=ai:laversa.laetitiaSummary: In this paper we address the issue of automatically learning parameters of spiking neural networks. Biological neurons are formalized as timed automata and synaptical connections are represented as shared channels among these automata. Such a formalism allows us to take into account several time-related aspects, such as the influence of past inputs in the computation of the potential value of each neuron, or the presence of the refractory period, a lapse of time immediately following the spike emission in which the neuron cannot emit. The proposed model is then formally validated: more precisely, we ensure that some relevant properties expressed as temporal logical formulae hold in the model. Once the validation step is accomplished, we take advantage of the proposed model to write an algorithm for learning synaptical weight values such that an expected behavior can be displayed. The technique we present takes inspiration from supervised learning ones: we compare the effective output of the network to the expected one and backpropagate proper corrective actions in the network. We develop several case studies including a mutual inhibition network.Solving two-dimensional cutting stock problem via a DNA computing algorithmhttps://zbmath.org/1530.680872024-04-15T15:10:58.286558Z"Dodge, M."https://zbmath.org/authors/?q=ai:dodge.m"MirHassani, S. A."https://zbmath.org/authors/?q=ai:mirhassani.seyed-ali"Hooshmand, F."https://zbmath.org/authors/?q=ai:hooshmand.fSummary: Two-dimensional cutting stock problem (TDCSP) is a well-known combinatorial optimization problem in which a given set of two-dimensional small pieces with different shapes should be cut from a given main board so that the demand of each small piece is satisfied and the total waste is minimized. Since TDCSP is an NP-complete problem, it is unsolvable in polynomial time on electronic computers. However, using the structure of DNA molecules, DNA computing algorithms are capable to solve NP-complete problems in polynomial time. In this paper, a DNA computing algorithm based on the sticker model is presented to find the optimal solution to TDCSP. It is proved that the time complexity of this algorithm on DNA computers is polynomial considering the number of small pieces and the length and width of the main board.Automatic design of arithmetic operation spiking neural P systemshttps://zbmath.org/1530.680882024-04-15T15:10:58.286558Z"Dong, Jianping"https://zbmath.org/authors/?q=ai:dong.jianping"Luo, Biao"https://zbmath.org/authors/?q=ai:luo.biao"Zhang, Gexiang"https://zbmath.org/authors/?q=ai:zhang.gexiang(no abstract)Self-assembly of 3-D structures using 2-D folding tileshttps://zbmath.org/1530.680892024-04-15T15:10:58.286558Z"Durand-Lose, Jérôme"https://zbmath.org/authors/?q=ai:durand-lose.jerome-olivier"Hendricks, Jacob"https://zbmath.org/authors/?q=ai:hendricks.jacob"Patitz, Matthew J."https://zbmath.org/authors/?q=ai:patitz.matthew-j"Perkins, Ian"https://zbmath.org/authors/?q=ai:perkins.ian"Sharp, Michael"https://zbmath.org/authors/?q=ai:sharp.michaelSummary: Self-assembly is a process which is ubiquitous in natural, especially biological systems. It occurs when groups of relatively simple components spontaneously combine to form more complex structures. While such systems have inspired a large amount of research into designing theoretical models of self-assembling systems, and even laboratory-based implementations of them, these artificial models and systems often tend to be lacking in one of the powerful features of natural systems (e.g. the assembly and folding of proteins), which is dynamic reconfigurability of structures. In this paper, we present a new mathematical model of self-assembly, based on the abstract Tile Assembly Model (aTAM), called the Flexible Tile Assembly Model (FTAM). In the FTAM, the individual components are 2-dimensional tiles as in the aTAM, but in the FTAM, bonds between the edges of tiles can be flexible, allowing bonds to flex and entire structures to reconfigure, thus allowing 2-dimensional components to form 3-dimensional structures. We analyze the powers and limitations of FTAM systems by (1) demonstrating how flexibility can be controlled to carefully build desired structures, and (2) showing how flexibility can be beneficially harnessed to form structures which can ``efficiently'' reconfigure into many different configurations and/or greatly varying configurations. We also show that with such power comes a heavy burden in terms of computational complexity of simulation and prediction by proving that for important properties of FTAM systems, determining their existence is intractable, even for properties which are easily computed for systems in less dynamic models.On the computational power of swarm automata using agents with position informationhttps://zbmath.org/1530.680902024-04-15T15:10:58.286558Z"Fujioka, Kaoru"https://zbmath.org/authors/?q=ai:fujioka.kaoruSummary: Based on swarm movements and computing models using multisets, a swarm automaton was introduced to construct a new computing system using swarm behavior in the computing process. In a swarm automaton, each agent changes by input and the interaction between agents, which leads to change the swarm represented by the multiset of agents. An input string is accepted by a swarm automaton depending on the conditions of the agents in the swarm. That is, an input string that leads the swarm to a specified condition is accepted. When we introduce position information for agents in a swarm automaton, the agent not only changes but also moves according to the nearby agents. In this paper, we introduce a language accepted by a swarm automaton based on the position of agents in a swarm. That is, a string is accepted when it leads to the swarm consisting of agents on the designated position. We focus on the number of agents in a swarm and consider the computing power of that swarm automaton. We show that any recursively enumerable language is accepted by a swarm automaton with only five agents using parallel transition.DNA origami words, graphical structures and their rewriting systemshttps://zbmath.org/1530.680912024-04-15T15:10:58.286558Z"Garrett, James"https://zbmath.org/authors/?q=ai:garrett.james-h-jun"Jonoska, Nataša"https://zbmath.org/authors/?q=ai:jonoska.natasa"Kim, Hwee"https://zbmath.org/authors/?q=ai:kim.hwee"Saito, Masahico"https://zbmath.org/authors/?q=ai:saito.masahicoSummary: We classify rectangular DNA origami structures according to their scaffold and staples organization by associating a graphical representation to each scaffold folding. Inspired by well studied Temperley-Lieb algebra, we identify basic modules that form the structures. The graphical description is obtained by `gluing' basic modules one on top of the other. To each module we associate a symbol such that gluing of modules corresponds to concatenating the associated symbols. Every word corresponds to a graphical representation of a DNA origami structure. A set of rewriting rules defines equivalent words that correspond to the same graphical structure. We propose two different types of basic module structures and corresponding rewriting rules. For each type, we provide the number of all possible structures through the number of equivalence classes of words. We also give a polynomial time algorithm that computes the shortest word for each equivalence class.On the power of membrane dissolution in polarizationless P systems with active membraneshttps://zbmath.org/1530.680922024-04-15T15:10:58.286558Z"Gazdag, Zsolt"https://zbmath.org/authors/?q=ai:gazdag.zsolt"Hajagos, Károly"https://zbmath.org/authors/?q=ai:hajagos.karolySummary: It is known that dissolution rules are necessary in polarizationless P systems with active membranes to solve problems beyond \(\mathbf{AC}^0\) using reasonable tight uniformity conditions [\textit{N. Murphy} and \textit{D. Woods}, Fundam. Inform. 134, No. 1--2, 129--152 (2014; Zbl 1315.68129)]. On the other hand, no solutions of such problems exist using only dissolution rules. In this paper, we show that the \(\mathbf{NL} \)-complete reachability problem can be solved in polynomial time by polarizationless P systems with active membranes using only dissolution rules under a suitable uniformity condition.Forming tile shapes with simple robotshttps://zbmath.org/1530.680932024-04-15T15:10:58.286558Z"Gmyr, Robert"https://zbmath.org/authors/?q=ai:gmyr.robert"Hinnenthal, Kristian"https://zbmath.org/authors/?q=ai:hinnenthal.kristian"Kostitsyna, Irina"https://zbmath.org/authors/?q=ai:kostitsyna.irina"Kuhn, Fabian"https://zbmath.org/authors/?q=ai:kuhn.fabian"Rudolph, Dorian"https://zbmath.org/authors/?q=ai:rudolph.dorian"Scheideler, Christian"https://zbmath.org/authors/?q=ai:scheideler.christian"Strothmann, Thim"https://zbmath.org/authors/?q=ai:strothmann.thimSummary: Motivated by the problem of manipulating nanoscale materials, we investigate the problem of reconfiguring a set of tiles into certain shapes by robots with limited computational capabilities. As a first step towards developing a general framework for these problems, we consider the problem of rearranging a connected set of hexagonal tiles by a single deterministic finite automaton. After investigating some limitations of a single-robot system, we show that a feasible approach to build a particular shape is to first rearrange the tiles into an intermediate structure by performing very simple tile movements. We introduce three types of such intermediate structures, each having certain advantages and disadvantages. Each of these structures can be built in asymptotically optimal \(O(n^2)\) rounds, where \(n\) is the number of tiles. As a proof of concept, we give an algorithm for reconfiguring a set of tiles into an equilateral triangle through one of the intermediate structures. Finally, we experimentally show that the algorithm for building the simplest of the three intermediate structures can be modified to be executed by multiple robots in a distributed manner, achieving an almost linear speedup in the case where the number of robots is reasonably small, and explain how the algorithm can be used to construct a triangle distributedly.Impossibility of strict assembly of infinite fractals by oritatamihttps://zbmath.org/1530.680942024-04-15T15:10:58.286558Z"Han, Yo-Sub"https://zbmath.org/authors/?q=ai:han.yo-sub"Kim, Hwee"https://zbmath.org/authors/?q=ai:kim.hweeSummary: RNA cotranscriptional folding is the phenomenon in which an RNA transcript folds upon itself while being synthesized out of a gene. The oritatami system is a computation model of this phenomenon, which lets its sequence (transcript) of beads (abstract molecules) fold cotranscriptionally by the interactions between beads according to the binding ruleset. In such models based on self-assembly, one of the key questions is the ability to construct fractal structures. We focus on the problem of generating an infinite fractal curves using a cyclic oritatami system, which has an infinite periodic transcript. We first establish a formal definition of drawing a curve using an oritatami system, proposing conditions and restrictions with reference to prior oritatami designs for possibly infinite conformations. Under such definition, we prove that it is impossible to draw a Koch curve or a Minkowski curve infinitely. We then establish sufficient conditions of infinite aperiodic curves that a cyclic oritatami system cannot fold.Transcript design problem of oritatami systemshttps://zbmath.org/1530.680952024-04-15T15:10:58.286558Z"Han, Yo-Sub"https://zbmath.org/authors/?q=ai:han.yo-sub"Kim, Hwee"https://zbmath.org/authors/?q=ai:kim.hwee"Seki, Shinnosuke"https://zbmath.org/authors/?q=ai:seki.shinnosukeSummary: RNA cotranscriptional folding refers to the phenomenon in which an RNA transcript folds upon itself while being synthesized out of a gene. Oritatami model is a computation model of this phenomenon, which lets its sequence (transcript) of beads (abstract molecules) fold cotranscriptionally by the interactions between beads according to its ruleset. We study the problem of designing a transcript that folds into the given conformation using the given ruleset, which is called the transcript design problem. We prove that the problem is computationally difficult to solve (NP-hard). Then we design efficient poly-time algorithms with additional restrictions on the oritatami system.Hierarchical growth is necessary and (sometimes) sufficient to self-assemble discrete self-similar fractalshttps://zbmath.org/1530.680962024-04-15T15:10:58.286558Z"Hendricks, Jacob"https://zbmath.org/authors/?q=ai:hendricks.jacob"Opseth, Joseph"https://zbmath.org/authors/?q=ai:opseth.joseph"Patitz, Matthew J."https://zbmath.org/authors/?q=ai:patitz.matthew-j"Summers, Scott M."https://zbmath.org/authors/?q=ai:summers.scott-mSummary: In this paper, we prove that in the abstract Tile Assembly Model (aTAM), an accretion-based model which only allows for a single tile to attach to a growing assembly at each step, there are no tile assembly systems capable of self-assembling the discrete self-similar fractals known as the ``H'' and ``U'' fractals. We then show that in a related model which allows for hierarchical self-assembly, the 2-Handed Assembly Model (2HAM), there does exist a tile assembly system which self-assembles the ``U'' fractal and conjecture that the same holds for the ``H'' fractal. This is the first example of discrete self similar fractals which self-assemble in the 2HAM but not in the aTAM, providing a direct comparison of the models and greater understanding of the power of hierarchical assembly.Real-time computability of real numbers by chemical reaction networkshttps://zbmath.org/1530.680972024-04-15T15:10:58.286558Z"Huang, Xiang"https://zbmath.org/authors/?q=ai:huang.xiang"Klinge, Titus H."https://zbmath.org/authors/?q=ai:klinge.titus-h"Lathrop, James I."https://zbmath.org/authors/?q=ai:lathrop.james-i"Li, Xiaoyuan"https://zbmath.org/authors/?q=ai:li.xiaoyuan"Lutz, Jack H."https://zbmath.org/authors/?q=ai:lutz.jack-hSummary: We explore the class of real numbers that are computed in real time by deterministic chemical reaction networks that are \textit{integral} in the sense that all their reaction rate constants are positive integers. We say that such a reaction network \textit{computes} a real number \(\alpha\) in \textit{real time} if it has a designated species \(X\) such that, when all species concentrations are set to zero at time \(t = 0\), the concentration \(x(t)\) of \(X\) is within \(2^{-t}\) of \(|\alpha |\) at all times \(t \ge 1\), and the concentrations of all other species are bounded. We show that every algebraic number and some transcendental numbers are real time computable by chemical reaction networks in this sense. We discuss possible implications of this for the 1965 Hartmanis-Stearns conjecture, which says that no irrational algebraic number is real time computable by a Turing machine.Simplifying the role of signals in tile self-assemblyhttps://zbmath.org/1530.680982024-04-15T15:10:58.286558Z"Kari, Lila"https://zbmath.org/authors/?q=ai:kari.lila"Simjour, Amirhossein"https://zbmath.org/authors/?q=ai:simjour.amirhosseinSummary: Sending signals through DNA-based structures is one of the methods used to enhance the capabilities of DNA self-assembly systems. Signal Tile Assembly Models at temperature one, in supertile-to-supertile attachment mode, have been showed to have universal computational power. We introduce a simplified signal tile assembly model, in one-tile-at-a-time attachment mode, and where signals can only be used to deactivate glues. We prove that such a simplified system at temperature one can still simulate a Turing machine. We also present a simplified signal tile assembly system, in supertile-to-supertile attachment mode, that assembles a thin, \(N \times N!\), rectangle and has tile complexity \(O(\log N)\). This result is an improvement over the tile complexity of existing models for thin rectangle self-assembly.Spiking neural P systems: main ideas and resultshttps://zbmath.org/1530.680992024-04-15T15:10:58.286558Z"Leporati, Alberto"https://zbmath.org/authors/?q=ai:leporati.alberto"Mauri, Giancarlo"https://zbmath.org/authors/?q=ai:mauri.giancarlo"Zandron, Claudio"https://zbmath.org/authors/?q=ai:zandron.claudioSummary: Spiking neural P systems are parallel and distributed computation devices which are inspired by the neuro-physiological behavior of biological neurons. In this paper we will present, with a tutorial approach, the main underlying ideas and the most interesting variants that have been proposed in the literature. In particular, we will discuss the results on the computational power of these models, both in terms of Turing completeness and of efficiency in solving hard problems, under different assumptions for information encoding, form and application of rules, and bounds on the main parameters defining the systems.Pumping lemmas for classes of languages generated by folding systemshttps://zbmath.org/1530.681002024-04-15T15:10:58.286558Z"Lucero, Jorge C."https://zbmath.org/authors/?q=ai:lucero.jorge-cSummary: Geometric folding processes are ubiquitous in natural systems ranging from protein biochemistry to patterns of insect wings and leaves. In a previous study, a folding operation between strings of formal languages was introduced as a model of such processes. The operation was then used to define a folding system (F-system) as a construct consisting of a core language, containing the strings to be folded, and a folding procedure language, which defines how the folding is done. This paper reviews main definitions associated with F-systems and next it determines necessary conditions for a language to belong to classes generated by such systems. The conditions are stated in the form of pumping lemmas and four classes are considered, in which the core and folding procedure languages are both regular, one of them is regular and the other context-free, or both are context-free. Full demonstrations of the lemmas are provided, and the analysis is illustrated with examples.Counting infinitely by oritatami co-transcriptional foldinghttps://zbmath.org/1530.681012024-04-15T15:10:58.286558Z"Maruyama, Kohei"https://zbmath.org/authors/?q=ai:maruyama.kohei"Seki, Shinnosuke"https://zbmath.org/authors/?q=ai:seki.shinnosuke(no abstract)Cellular automata modelling of slime mould actin network signallinghttps://zbmath.org/1530.681022024-04-15T15:10:58.286558Z"Mayne, Richard"https://zbmath.org/authors/?q=ai:mayne.richard"Adamatkzy, Andrew"https://zbmath.org/authors/?q=ai:adamatkzy.andrew(no abstract)Tissue P systems with evolutional communication rules with two objects in the left-hand sidehttps://zbmath.org/1530.681032024-04-15T15:10:58.286558Z"Orellana-Martín, David"https://zbmath.org/authors/?q=ai:orellana-martin.david"Valencia-Cabrera, Luis"https://zbmath.org/authors/?q=ai:valencia-cabrera.luis"Song, Bosheng"https://zbmath.org/authors/?q=ai:song.bosheng"Pan, Linqiang"https://zbmath.org/authors/?q=ai:pan.linqiang"Pérez-Jiménez, Mario J."https://zbmath.org/authors/?q=ai:perez-jimenez.mario-jSummary: In the framework of \textit{Membrane Computing}, several efficient solutions to computationally hard problems have been given. To find new borderlines between families of P systems that can solve them and the ones that cannot is an important task to tackle the \textbf{P} versus \textbf{NP} problem. Adding syntactic and/or semantic ingredients can mean passing from non-efficiency to \textit{presumed} efficiency. Here, we try to get narrow frontiers, setting the stage to adapt efficient solutions from a family of P systems to another one. In order to do that, a solution to the SAT problem is given by means of a family of tissue P systems with evolutional symport/antiport rules and cell separation with the restriction that both the left-hand side and the right-hand side of the rules have at most two objects; that is, with recognizer P systems from \({\mathcal{TSEC}}(2, 2)\). This result improves a previous one, when 3 objects could be used in the left-hand side of the evolutional communication rulesMinimal reversible circuit synthesis on a DNA computerhttps://zbmath.org/1530.681042024-04-15T15:10:58.286558Z"Sarkar, Mayukh"https://zbmath.org/authors/?q=ai:sarkar.mayukh"Ghosal, Prasun"https://zbmath.org/authors/?q=ai:ghosal.prasun"Mohanty, Saraju P."https://zbmath.org/authors/?q=ai:mohanty.saraju-p(no abstract)Verification in staged tile self-assemblyhttps://zbmath.org/1530.681052024-04-15T15:10:58.286558Z"Schweller, Robert"https://zbmath.org/authors/?q=ai:schweller.robert-t"Winslow, Andrew"https://zbmath.org/authors/?q=ai:winslow.andrew"Wylie, Tim"https://zbmath.org/authors/?q=ai:wylie.timSummary: We prove the unique assembly and unique shape verification problems, benchmark measures of self-assembly model power, are \(\textsf{coNP}^{\textsf{NP}}\)-hard and contained in \textsf{PSPACE} (and in \(\Pi^\textsf{P}_{2s}\) for staged systems with \(s\) stages). En route, we prove that unique shape verification problem in the 2HAM is \(\textsf{coNP}^{\textsf{NP}}\)-complete.Morphogenetic computing: computability and complexity resultshttps://zbmath.org/1530.681062024-04-15T15:10:58.286558Z"Sosík, Petr"https://zbmath.org/authors/?q=ai:sosik.petrSummary: A morphogenetic (M) system is an abstract computational model combining properties of membrane (P) systems, such as computing via abstract particles in separate compartments regulating their workflow, with algorithmic self-assembly generalizing original Wang tiles to arbitrary polytopes forming complex shapes in 2D/3D (or generally, \(d\) D) space. Even very simple morphogenetic systems can exhibit complex self-organizing behaviour and, at the abstract level, one can observe characteristic properties of morphogenetic phenomena such as controlled growth, self-reproduction, homeostasis and self-healing. Here we focus on computational aspects of the morphogenetic systems. After summarizing a series of results related to their computational universality (in the Turing sense) and computational complexity, we present two small universal M systems (one of them self-healing) and we also demonstrate how morphogenetic systems relate to the classes \textbf{P} and \textbf{NP}.Self-healing Turing-universal computation in morphogenetic systemshttps://zbmath.org/1530.681072024-04-15T15:10:58.286558Z"Sosík, Petr"https://zbmath.org/authors/?q=ai:sosik.petr"Garzon, Max"https://zbmath.org/authors/?q=ai:garzon.max-h"Drastík, Jan"https://zbmath.org/authors/?q=ai:drastik.janSummary: A morphogenetic system (M system) is an abstract computational model inspired by characteristic properties of morphogenetic phenomena such as controlled growth, self-reproduction, homeostasis and self-healing in living systems. Besides selected principles of membrane computing, M systems also rely on algorithmic self-assembly of abstract tiles unfolding in a 3D (or generally, \(d\) D) space. Explicit spatial arrangements for interaction among an M system's components are crucial for its function. From a computational viewpoint, key features of M systems include their computational universality and their efficiency to solve difficult problems. Both computational universality (in the Turing sense) and self-healing properties (in the sense of the algorithmic tile assembly model) have been demonstrated for different M systems in prior publications. Here, we demonstrate that both of these properties can be simultaneously achieved in a single M system. We present a Turing universal string acceptor M system that also exhibits self-healing capabilities of degree 1. This result is rather surprising since Turing machines are usually very sensitive to minor damage to their internal structure. The result thus sheds light on the power and importance of geometric and spatial arrangements for the reliability and robustness of a computational system.\textit{CRN}++: molecular programming languagehttps://zbmath.org/1530.681082024-04-15T15:10:58.286558Z"Vasić, Marko"https://zbmath.org/authors/?q=ai:vasic.marko"Soloveichik, David"https://zbmath.org/authors/?q=ai:soloveichik.david"Khurshid, Sarfraz"https://zbmath.org/authors/?q=ai:khurshid.sarfrazSummary: Synthetic biology is a rapidly emerging research area, with expected wide-ranging impact in biology, nanofabrication, and medicine. A key technical challenge lies in embedding computation in molecular contexts where electronic micro-controllers cannot be inserted. This necessitates effective representation of computation using molecular components. While previous work established the Turing-completeness of chemical reactions, defining representations that are faithful, efficient, and practical remains challenging . This paper introduces \textit{CRN}++, a new language for programming deterministic (mass-action) chemical kinetics to perform computation. We present its syntax and semantics, and build a compiler translating \textit{CRN}++ programs into chemical reactions, thereby laying the foundation of a comprehensive framework for molecular programming. Our language addresses the key challenge of embedding familiar imperative constructs into a set of chemical reactions happening simultaneously and manipulating real-valued concentrations. Although some deviation from ideal output value cannot be avoided, we develop methods to minimize the error, and implement error analysis tools. We demonstrate the feasibility of using \textit{CRN}++on a suite of well-known algorithms for discrete and real-valued computation. \textit{CRN}++ can be easily extended to support new commands or chemical reaction implementations, and thus provides a foundation for developing more robust and practical molecular programs.A tutorial on the formal framework for spiking neural P systemshttps://zbmath.org/1530.681092024-04-15T15:10:58.286558Z"Verlan, Sergey"https://zbmath.org/authors/?q=ai:verlan.sergey"Zhang, Gexiang"https://zbmath.org/authors/?q=ai:zhang.gexiangSummary: The model of Spiking Neural P systems (SNP systems) is a widespread computational model in the area of membrane computing. It has numerous applications, especially related to machine learning. Most of these applications require a custom variant of SNP systems, differing by the rule form and by semantics. The model of network of cells and the formal framework for SNP systems were developed to help the analysis of such custom models, to compare and relate them to each other and to other models of computing. The model specifies the data structure, the rules and the update procedure, while the formal framework concentrates on how the input, output and the choice of the update strategy are handled. Together, these concepts specify a concrete instance of a network of cells that strongly bisimulates the desired model, thus making easier the process of the creation of new models and the extension of existing ones. Since the formal framework is rather generic, it might be slightly complex to use it for concrete cases. This paper provides a tutorial that explains the model of networks of cells and the basic concepts used in the formal framework for SNP systems. It gives a series of examples for the analysis of existing models, their bisimulation and their extension by different features.Molecular computing for Markov chainshttps://zbmath.org/1530.681102024-04-15T15:10:58.286558Z"Zhang, Chuan"https://zbmath.org/authors/?q=ai:zhang.chuan"Shen, Ziyuan"https://zbmath.org/authors/?q=ai:shen.ziyuan"Wei, Wei"https://zbmath.org/authors/?q=ai:wei.wei.9|wei.wei.3|wei.wei.11|wei.wei.8|wei.wei.12|wei.wei.2|wei.wei.16"Zhao, Jing"https://zbmath.org/authors/?q=ai:zhao.jing|zhao.jing.5|zhao.jing.1|zhao.jing.2|zhao.jing.3|zhao.jing.6|zhao.jing.8|zhao.jing.4"Zhang, Zaichen"https://zbmath.org/authors/?q=ai:zhang.zaichen"You, Xiaohu"https://zbmath.org/authors/?q=ai:you.xiaohuSummary: In this paper, it is presented a methodology for implementing arbitrarily constructed time-homogenous Markov chains with biochemical systems. Not only discrete but also continuous-time Markov chains are allowed to be computed. By employing chemical reaction networks as a programmable language, molecular concentrations serve to denote both input and output values. One reaction network is elaborately designed for each chain. The evolution of species' concentrations over time well matches the transient solutions of the target continuous-time Markov chain, while equilibrium concentrations can indicate the steady state probabilities. Additionally, second-order Markov chains are considered for implementation, with bimolecular reactions rather than unary ones. An original scheme is put forward to compile unimolecular systems to DNA strand displacement reactions for the sake of future physical implementations. Deterministic, stochastic and DNA simulations are provided to enhance correctness, validity and feasibility.Particle computation: complexity, algorithms, and logichttps://zbmath.org/1530.681112024-04-15T15:10:58.286558Z"Becker, Aaron T."https://zbmath.org/authors/?q=ai:becker.aaron-t"Demaine, Erik D."https://zbmath.org/authors/?q=ai:demaine.erik-d"Fekete, Sándor P."https://zbmath.org/authors/?q=ai:fekete.sandor-p"Lonsford, Jarrett"https://zbmath.org/authors/?q=ai:lonsford.jarrett"Morris-Wright, Rose"https://zbmath.org/authors/?q=ai:morris-wright.roseSummary: We investigate algorithmic control of a large swarm of mobile particles (such as robots, sensors, or building material) that move in a 2D workspace using a global input signal (such as gravity or a magnetic field). Upon activation of the field, each particle moves maximally in the same direction until forward progress is blocked by a stationary obstacle or another stationary particle. In an open workspace, this system model is of limited use because it has only two controllable degrees of freedom -- all particles receive the same inputs and move uniformly. We show that adding a maze of obstacles to the environment can make the system drastically more complex but also more useful. We provide a wide range of results for a wide range of questions. These can be subdivided into \textit{external} algorithmic problems, in which particle configurations serve as input for computations that are performed elsewhere, and \textit{internal} logic problems, in which the particle configurations themselves are used for carrying out computations. For external algorithms, we give both negative and positive results. If we are \textit{given} a set of stationary obstacles, we prove that it is NP-hard to decide whether a given initial configuration of unit-sized particles can be transformed into a desired target configuration. Moreover, we show that finding a control sequence of minimum length is PSPACE-complete. We also work on the inverse problem, providing constructive algorithms to \textit{design} workspaces that efficiently implement arbitrary permutations between different configurations. For internal logic, we investigate how arbitrary computations can be implemented. We demonstrate how to encode \textit{dual-rail logic} to build a universal logic gate that concurrently evaluates \textsc{and}, \textsc{nand}, \textsc{nor}, and \textsc{or} operations. Using many of these gates and appropriate interconnects, we can evaluate any logical expression. However, we establish that simulating the full range of complex interactions present in arbitrary digital circuits encounters a fundamental difficulty: a \textsc{fan-out} gate cannot be generated. We resolve this missing component with the help of \(2 \times 1\) particles, which can create \textsc{fan-out} gates that produce multiple copies of the inputs. Using these gates we provide rules for replicating arbitrary digital circuits.Reservoir computing quality: connectivity and topologyhttps://zbmath.org/1530.681122024-04-15T15:10:58.286558Z"Dale, Matthew"https://zbmath.org/authors/?q=ai:dale.matthew"O'Keefe, Simon"https://zbmath.org/authors/?q=ai:okeefe.simon"Sebald, Angelika"https://zbmath.org/authors/?q=ai:sebald.angelika"Stepney, Susan"https://zbmath.org/authors/?q=ai:stepney.susan"Trefzer, Martin A."https://zbmath.org/authors/?q=ai:trefzer.martin-aSummary: We explore the effect of connectivity and topology on the dynamical behaviour of Reservoir Computers. At present, considerable effort is taken to design and hand-craft physical reservoir computers. Both structure and physical complexity are often pivotal to task performance, however, assessing their overall importance is challenging. Using a recently developed framework, we evaluate and compare the dynamical freedom (referring to quality) of neural network structures, as an analogy for physical systems. The results quantify how structure affects the behavioural range of networks. It demonstrates how high quality reached by more complex structures is often also achievable in simpler structures with greater network size. Alternatively, quality is often improved in smaller networks by adding greater connection complexity. This work demonstrates the benefits of using dynamical behaviour to assess the quality of computing substrates, rather than evaluation through benchmark tasks that often provide a narrow and biased insight into the computing quality of physical systems.Geometric tiles and powers and limitations of geometric hindrance in self-assemblyhttps://zbmath.org/1530.681132024-04-15T15:10:58.286558Z"Hader, Daniel"https://zbmath.org/authors/?q=ai:hader.daniel"Patitz, Matthew J."https://zbmath.org/authors/?q=ai:patitz.matthew-jSummary: Tile-based self-assembly systems are capable of universal computation and algorithmically directed growth. Systems capable of such behaviors typically make use of ``glue cooperation'' in which the glues on at least 2 sides of a tile must match and bind to those exposed on the perimeter of an assembly for that tile to attach. However, several models have been developed which utilize ``weak cooperation'', where only a single glue needs to bind but other preventative forces (such as geometric, or steric, hindrance) provide additional selection for which tiles may attach, and where this allows for algorithmic behavior. In this paper we first work in a model where tiles are allowed to have geometric bumps and dents on their edges. We show how such ``geometric'' tiles can simulate systems of square tiles with complex glue functions (using asymptotically optimal sizes of bumps and dents). We then show that at scale factor 1 it is impossible for geometric tiles to simulate the behavior of systems which can include duples (i.e. tiles either twice as long or twice as tall as square tiles), and also that with only weak cooperation via geometric hindrance, no system in any model can simulate even a class of tightly constrained, deterministic cooperative systems. This helps to further define the limits of the powers of systems relying on geometric hindrance instead of glue cooperation.Self-assembly of 4-sided fractals in the two-handed tile assembly modelhttps://zbmath.org/1530.681142024-04-15T15:10:58.286558Z"Hendricks, Jacob"https://zbmath.org/authors/?q=ai:hendricks.jacob"Opseth, Joseph"https://zbmath.org/authors/?q=ai:opseth.josephSummary: We consider the self-assembly of fractals in one of the most well-studied models of tile based self-assembling systems known as the Two-Handed Tile Assembly Model (2HAM). In particular, we focus our attention on a class of fractals called discrete self-similar fractals (a class of fractals that includes the discrete Sierpiński carpet). We present a 2HAM system that finitely self-assembles the discrete Sierpiński carpet with scale factor 1. Moreover, the 2HAM system that we give lends itself to being generalized and we describe how this system can be modified to obtain a 2HAM system that finitely self-assembles one of any fractal from an infinite set of fractals which we call 4\textit{-sided fractals}. The 2HAM systems we give in this paper are the first examples of systems that finitely self-assemble discrete self-similar fractals at scale factor 1 in a purely growth model of self-assembly. Finally, we show that there exists a 3\textit{-sided fractal} (which is not a tree fractal) that cannot be finitely self-assembled by any 2HAM system.Tetrahedral tile pasting systemshttps://zbmath.org/1530.681152024-04-15T15:10:58.286558Z"Kalyani, T."https://zbmath.org/authors/?q=ai:kalyani.thiyagarajan"Annadurai, S."https://zbmath.org/authors/?q=ai:annadurai.suganya"Raman, T. T."https://zbmath.org/authors/?q=ai:raman.t-t"Thomas, D. G."https://zbmath.org/authors/?q=ai:thomas.durairaj-gnanarajSummary: Tile pasting system is a parallel generating model which glues two square tiles at their edges to create intricate tiling patterns. It is extended by using three dimensional objects namely tetrahedral tiles and the patterns generated are used to decorate floors and walls. In the literature \(k\)-Tabled Tetrahedral Tile Pasting System \((k\)-TTTPS) and Tetrahedral Tile Pasting \(P\) System (TetTPPS) were introduced to generate tetrahedral picture patterns. In this paper, Controlled Tabled Tetrahedral Tile Pasting System (CTTTPS) is proposed to generate tetrahedral picture patterns and CTTTPS is compared with \(k\)-TTTPS and TetTPPS in terms of generative powers. It is proved that CTTTPS has more generative power than the generative powers of \(k\)-TTTPS and TetTPPS. Extended Tetrahedral Tile Pasting System (ETTPS) and Extended Tetrahedral Tile Pasting P System (ETTPPS) are also proposed in this paper and are compared with CTTTPS in terms of their generative powers. This study has connections with pattern recognition and image analysis with applications in tiling of tetrahedral patterns.Self-assembly of shapes at constant scale using repulsive forceshttps://zbmath.org/1530.681162024-04-15T15:10:58.286558Z"Luchsinger, Austin"https://zbmath.org/authors/?q=ai:luchsinger.austin"Schweller, Robert"https://zbmath.org/authors/?q=ai:schweller.robert-t"Wylie, Tim"https://zbmath.org/authors/?q=ai:wylie.timSummary: The algorithmic self-assembly of shapes has been considered in several models of self-assembly. For the problem of \textit{shape construction}, we consider an extended version of the two-handed tile assembly model, which contains positive (attractive) and negative (repulsive) interactions. As a result, portions of an assembly can become unstable and detach. In this model, we utilize fuel-efficient computation to perform Turing machine simulations for the construction of the shape. In this paper, we show how an arbitrary shape can be constructed using an asymptotically optimal number of distinct tile types (based on the shape's Kolmogorov complexity). We achieve this at \(O(1)\) scale factor in this straightforward model, whereas all previous results with sublinear scale factors utilize powerful self-assembly models containing features such as staging, tile deletion, chemical reaction networks, and tile activation/deactivation. Furthermore, the computation and construction in our result only creates constant-size garbage assemblies as a byproduct of assembling the shape.The representational entity in physical computinghttps://zbmath.org/1530.681172024-04-15T15:10:58.286558Z"Stepney, Susan"https://zbmath.org/authors/?q=ai:stepney.susan"Kendon, Viv"https://zbmath.org/authors/?q=ai:kendon.viv-mSummary: We have developed abstraction/representation (AR) theory to answer the question ``When does a physical system compute?'' AR theory requires the existence of a \textit{representational entity} (RE), but the vanilla theory does not explicitly include the RE in its definition of physical computing. Here we extend the theory by showing how the RE forms a linked complementary model to the physical computing model. We show that the RE does not need to be a human brain, by demonstrating its use in the case of intrinsic computing in a non-human RE: a bacterium.Universal logic elements constructed on the Turing tumblehttps://zbmath.org/1530.681182024-04-15T15:10:58.286558Z"Tomita, Takahiro"https://zbmath.org/authors/?q=ai:tomita.takahiro"Lee, Jia"https://zbmath.org/authors/?q=ai:lee.jia"Isokawa, Teijiro"https://zbmath.org/authors/?q=ai:isokawa.teijiro"Peper, Ferdinand"https://zbmath.org/authors/?q=ai:peper.ferdinand"Yumoto, Takayuki"https://zbmath.org/authors/?q=ai:yumoto.takayuki"Kamiura, Naotake"https://zbmath.org/authors/?q=ai:kamiura.naotakeSummary: This paper presents a mathematical model for a mechanical computer called the \textit{Turing Tumble}. We show that our model called \textit{Turing Tumble Model (TTM)} is computationally universal under the assumptions that a configuration of TTM is sufficiently large and that local interactions between elements can be transferred without limitations. The Turing Tumble has a strict constraint, based on gravity, since signals can only move from top to bottom. We introduce a uniform scheme that takes into account this restriction in directionality to construct universal machines in the TTM based on directed acyclic graphs. This model may be useful for implementing computers that exploit mechanical interactions in nature, especially those on micrometer-scales.Solving combinatorial optimisation problems using oscillator based Ising machineshttps://zbmath.org/1530.681192024-04-15T15:10:58.286558Z"Wang, Tianshi"https://zbmath.org/authors/?q=ai:wang.tianshi"Wu, Leon"https://zbmath.org/authors/?q=ai:wu.leon"Nobel, Parth"https://zbmath.org/authors/?q=ai:nobel.parth"Roychowdhury, Jaijeet"https://zbmath.org/authors/?q=ai:roychowdhury.jaijeet(no abstract)A quantum-inspired vortex search algorithm with application to function optimizationhttps://zbmath.org/1530.681202024-04-15T15:10:58.286558Z"Li, Panchi"https://zbmath.org/authors/?q=ai:li.panchi"Zhao, Ya"https://zbmath.org/authors/?q=ai:zhao.ya(no abstract)Computational complexity characterization of protecting elections from briberyhttps://zbmath.org/1530.681212024-04-15T15:10:58.286558Z"Chen, Lin"https://zbmath.org/authors/?q=ai:chen.lin.1"Sunny, Ahmed"https://zbmath.org/authors/?q=ai:sunny.ahmed-imtiaz"Xu, Lei"https://zbmath.org/authors/?q=ai:xu.lei.1"Xu, Shouhuai"https://zbmath.org/authors/?q=ai:xu.shouhuai"Gao, Zhimin"https://zbmath.org/authors/?q=ai:gao.zhimin"Lu, Yang"https://zbmath.org/authors/?q=ai:lu.yang.1"Shi, Weidong"https://zbmath.org/authors/?q=ai:shi.weidong"Shah, Nolan"https://zbmath.org/authors/?q=ai:shah.nolanSummary: The bribery problem in election has received considerable attention in the literature, upon which various algorithmic and complexity results have been obtained. It is thus natural to ask whether we can protect an election from potential bribery. We assume that the protector can protect a voter with some cost (e.g., by isolating the voter from potential bribers). A protected voter cannot be bribed. Under this setting, we consider the following bi-level decision problem: Is it possible for the protector to protect a proper subset of voters such that no briber with a fixed budget on bribery can alter the election result? The goal of this paper is to give a full picture on the complexity of protection problems. We give an extensive study on the protection problem and provide algorithmic and complexity results. Comparing our results with that on the bribery problems, we observe that the protection problem is in general significantly harder. Indeed, it becomes \(\varSigma_2^p\)-complete even for very restricted special cases, while most bribery problems lie in NP. However, it is not necessarily the case that the protection problem is always harder. Some of the protection problems can still be solved in polynomial time, while some of them remain as hard as the bribery problem under the same setting.
For the entire collection see [Zbl 1458.68009].The word problem for braided monoidal categories is unknot-hardhttps://zbmath.org/1530.681222024-04-15T15:10:58.286558Z"Delpeuch, Antonin"https://zbmath.org/authors/?q=ai:delpeuch.antonin"Vicary, Jamie"https://zbmath.org/authors/?q=ai:vicary.jamieSummary: We show that the word problem for braided monoidal categories is at least as hard as the unknotting problem. As a corollary, so is the word problem for Gray categories. We conjecture that the word problem for Gray categories is decidable.
For the entire collection see [Zbl 1522.68034].There is no APTAS for 2-dimensional vector bin packing: revisitedhttps://zbmath.org/1530.681232024-04-15T15:10:58.286558Z"Ray, Arka"https://zbmath.org/authors/?q=ai:ray.arkaSummary: We study the Vector Bin Packing and the Vector Bin Covering problems, multidimensional generalizations of the Bin Packing and the Bin Covering problems, respectively. In the Vector Bin Packing, we are given a set of \(d\)-dimensional vectors from \([0,1]^d\) and the aim is to partition the set into the minimum number of bins such that for each bin \(B\), each component of the sum of the vectors in \(B\) is at most 1. \textit{G. J. Woeginger} [Inf. Process. Lett. 64, No. 6, 293--297 (1997; Zbl 1338.68122)] claimed that the problem has no APTAS for dimensions greater than or equal to 2. We note that there was a slight oversight in the original proof. In this work, we give a revised proof using some additional ideas from
[\textit{N. Bansal} et al., Math. Oper. Res. 31, No. 1, 31--49 (2006; Zbl 1278.90324); \textit{M. Chlebík} and \textit{J. Chlebíková}, J. Discrete Algorithms 7, No. 3, 291--305 (2009; Zbl 1178.68282)]. In fact, we show that it is NP-hard to get an asymptotic approximation ratio better than \(\frac{600}{599}\).
An instance of Vector Bin Packing is called \(\delta\)-skewed if every item has at most one dimension greater than \(\delta\). As a natural extension of our general \(d\)-Dimensional Vector Bin Packing result we show that for \(\varepsilon\in(0,\frac{1}{2500})\) it is NP-hard to obtain a \((1+\varepsilon)\)-approximation for \(\delta\)-Skewed Vector Bin Packing if \(\delta>20\sqrt{\varepsilon}\).
In the Vector Bin Covering problem given a set of \(d\)-dimensional vectors from \([0,1]^d\), the aim is to obtain a family of disjoint subsets (called bins) with the maximum cardinality such that for each bin \(B\), each component of the sum of the vectors in \(B\) is at least 1. Using ideas similar to our Vector Bin Packing result, we show that for Vector Bin Covering there is no APTAS for dimensions greater than or equal to 2. In fact, we show that it is NP-hard to get an asymptotic approximation ratio better than \(\frac{998}{997}\).Complexity through translations for modal logic with recursionhttps://zbmath.org/1530.681242024-04-15T15:10:58.286558Z"Aceto, Luca"https://zbmath.org/authors/?q=ai:aceto.luca"Achilleos, Antonis"https://zbmath.org/authors/?q=ai:achilleos.antonis"Anastasiadi, Elli"https://zbmath.org/authors/?q=ai:anastasiadi.elli"Francalanza, Adrian"https://zbmath.org/authors/?q=ai:francalanza.adrian"Ingolfsdottir, Anna"https://zbmath.org/authors/?q=ai:ingolfsdottir.annaSummary: This paper studies the complexity of classical modal logics and of their extension with fixed-point operators, using translations to transfer results across logics. In particular, we show several complexity results for multi-agent logics via translations to and from the \(\mu\)-calculus and modal logic, which allow us to transfer known upper and lower bounds. We also use these translations to introduce a terminating tableau system for the logics we study, based on Kozen's tableau for the mu-calculus, and the one of Fitting and Massacci for modal logic.
For the entire collection see [Zbl 1522.68028].On the existential fragments of local first-order logics with datahttps://zbmath.org/1530.681252024-04-15T15:10:58.286558Z"Bollig, Benedikt"https://zbmath.org/authors/?q=ai:bollig.benedikt"Sangnier, Arnaud"https://zbmath.org/authors/?q=ai:sangnier.arnaud"Stietel, Olivier"https://zbmath.org/authors/?q=ai:stietel.olivierSummary: We study first-order logic over unordered structures whose elements carry a finite number of data values from an infinite domain which can be compared wrt. equality. As the satisfiability problem for this logic is undecidable in general, in a previous work, we have introduced a family of local fragments that restrict quantification to neighbourhoods of a given reference point. We provide here the precise complexity characterisation of the satisfiability problem for the existential fragments of this local logic depending on the number of data values carried by each element and the radius of the considered neighbourhoods.
For the entire collection see [Zbl 1522.68028].Capturing bisimulation-invariant exponential-time complexity classeshttps://zbmath.org/1530.681262024-04-15T15:10:58.286558Z"Bruse, Florian"https://zbmath.org/authors/?q=ai:bruse.florian"Kronenberger, David"https://zbmath.org/authors/?q=ai:kronenberger.david"Lange, Martin"https://zbmath.org/authors/?q=ai:lange.martinSummary: Otto's Theorem characterises the bisimulation-invariant PTIME queries over graphs as exactly those that can be formulated in the polyadic \(\mu\)-calculus, hinging on the Immerman-Vardi Theorem which characterises PTIME (over ordered structures) by First-Order Logic with least fixpoints. This connection has been extended to characterise bisimulation-invariant EXPTIME by an extension of the polyadic mu-calculus with functions on predicates, making use of Immerman's characterisation of EXPTIME by Second-Order Logic with least fixpoints.
In this paper we show that the bisimulation-invariant versions of all classes in the exponential time hierarchy have logical counterparts which arise as extensions of the polyadic \(\mu\)-calculus by higher-order functions. This makes use of the characterisation of \(k\)-EXPTIME by Higher-Order Logic (of order \(k+1\)) with least fixpoints, due to Freire and Martins.
For the entire collection see [Zbl 1522.68028].Descriptive complexity of deterministic polylogarithmic timehttps://zbmath.org/1530.681272024-04-15T15:10:58.286558Z"Ferrarotti, Flavio"https://zbmath.org/authors/?q=ai:ferrarotti.flavio-antonio"González, Senén"https://zbmath.org/authors/?q=ai:gonzalez.senen"Turull Torres, José María"https://zbmath.org/authors/?q=ai:turull-torres.jose-maria"Van Den Bussche, Jan"https://zbmath.org/authors/?q=ai:van-den-bussche.jan"Virtema, Jonni"https://zbmath.org/authors/?q=ai:virtema.jonniSummary: We propose a logical characterization of problems solvable in deterministic polylogarithmic time (PolylogTime). We introduce a novel two-sorted logic that separates the elements of the input domain from the bit positions needed to address these elements. In the course of proving that our logic indeed captures PolylogTime on finite ordered structures, we introduce a variant of random-access Turing machines that can access the relations and functions of the structure directly. We investigate whether an explicit predicate for the ordering of the domain is needed in our logic. Finally, we present the open problem of finding an exact characterization of order-invariant queries in PolylogTime.
For the entire collection see [Zbl 1418.03008].Effective divergence analysis for linear recurrence sequenceshttps://zbmath.org/1530.681282024-04-15T15:10:58.286558Z"Almagor, Shaull"https://zbmath.org/authors/?q=ai:almagor.shaull"Chapman, Brynmor"https://zbmath.org/authors/?q=ai:chapman.brynmor-k"Hosseini, Mehran"https://zbmath.org/authors/?q=ai:hosseini.mehran"Ouaknine, Joël"https://zbmath.org/authors/?q=ai:ouaknine.joel-o"Worrell, James"https://zbmath.org/authors/?q=ai:worrell.james-bSummary: We study the growth behaviour of rational linear recurrence sequences. We show that for low-order sequences, divergence is decidable in polynomial time. We also exhibit a polynomial-time algorithm which takes as input a divergent rational linear recurrence sequence and computes effective fine-grained lower bounds on the growth rate of the sequence.
For the entire collection see [Zbl 1402.68024].Analyzing robustness of Angluin's \(\mathrm{L}^\ast\) algorithm in presence of noisehttps://zbmath.org/1530.681292024-04-15T15:10:58.286558Z"Khmelnitsky, Igor"https://zbmath.org/authors/?q=ai:khmelnitsky.igor"Haddad, Serge"https://zbmath.org/authors/?q=ai:haddad.serge"Ye, Lina"https://zbmath.org/authors/?q=ai:ye.lina"Barbot, Benoît"https://zbmath.org/authors/?q=ai:barbot.benoit"Bollig, Benedikt"https://zbmath.org/authors/?q=ai:bollig.benedikt"Leucker, Martin"https://zbmath.org/authors/?q=ai:leucker.martin"Neider, Daniel"https://zbmath.org/authors/?q=ai:neider.daniel"Roy, Rajarshi"https://zbmath.org/authors/?q=ai:roy.rajarshiSummary: Angluin's \(\mathrm{L}^\ast\) algorithm learns the minimal (complete) deterministic finite automaton (DFA) of a regular language using membership and equivalence queries. Its probabilistic approximatively correct (PAC) version substitutes an equivalence query by a large enough set of random membership queries to get a high level confidence to the answer. Thus it can be applied to any kind of (also non-regular) device and may be viewed as an algorithm for synthesizing an automaton abstracting the behavior of the device based on observations. Here we are interested on how Angluin's PAC learning algorithm behaves for devices which are obtained from a DFA by introducing some noise. More precisely we study whether Angluin's algorithm reduces the noise and produces a DFA closer to the original one than the noisy device. We propose several ways to introduce the noise: (1) the noisy device inverts the classification of words w.r.t. the DFA with a small probability, (2) the noisy device modifies with a small probability the letters of the word before asking its classification w.r.t. the DFA, and (3) the noisy device combines the classification of a word w.r.t. the DFA and its classification w.r.t. a counter automaton. Our experiments were performed on several hundred DFAs.
Our main contributions, bluntly stated, consist in showing that: (1) Angluin's algorithm behaves well whenever the noisy device is produced by a random process, (2) but poorly with a structured noise, and, that (3) almost surely randomness yields systems with non-recursively enumerable languages.
For the entire collection see [Zbl 1522.68028].Symbolic specialization of rewriting logic theories with \textsf{Presto}https://zbmath.org/1530.681302024-04-15T15:10:58.286558Z"Alpuente, María"https://zbmath.org/authors/?q=ai:alpuente.maria"Escobar, Santiago"https://zbmath.org/authors/?q=ai:escobar.santiago"Sapiña, Julia"https://zbmath.org/authors/?q=ai:sapina.julia"Ballis, Demis"https://zbmath.org/authors/?q=ai:ballis.demisSummary: This paper introduces \textsf{Presto}, a symbolic partial evaluator for Maude's rewriting logic theories that can improve system analysis and verification. In \textsf{Presto}, the automated optimization of a conditional rewrite theory \(\mathscr{R}\) (whose rules define the concurrent transitions of a system) is achieved by partially evaluating, with respect to the rules of \(\mathscr{R}\), an underlying, companion equational logic theory \(\mathscr{E}\) that specifies the algebraic structure of the system states of \(\mathscr{R}\). This can be particularly useful for specializing an overly general equational theory \(\mathscr{E}\) whose operators may obey complex combinations of associativity, commutativity, and/or identity axioms, when being plugged into a host rewrite theory \(\mathscr{R}\) as happens, for instance, in protocol analysis, where sophisticated equational theories for cryptography are used. \textsf{Presto} implements different unfolding operators that are based on \textit{folding variant narrowing} (the symbolic engine of Maude's equational theories). When combined with an appropriate abstraction algorithm, they allow the specialization to be adapted to the theory termination behavior and bring significant improvement while ensuring strong correctness and termination of the specialization. We demonstrate the effectiveness of \textsf{Presto} in several examples of protocol analysis where it achieves a significant speed-up. Actually, the transformation provided by \textsf{Presto} may cut down an infinite folding variant narrowing space to a finite one, and moreover, some of the costly algebraic axioms and rule conditions may be eliminated as well. As far as we know, this is the first partial evaluator for Maude that respects the semantics of functional, logic, concurrent, and object-oriented computations.Structure sensitive tier projection: applications and formal propertieshttps://zbmath.org/1530.681312024-04-15T15:10:58.286558Z"De Santo, Aniello"https://zbmath.org/authors/?q=ai:de-santo.aniello"Graf, Thomas"https://zbmath.org/authors/?q=ai:graf.thomasSummary: The subregular approach has revealed that the phonological surface patterns found in natural language are much simpler than previously assumed. Most patterns belong to the subregular class of tier-based strictly local languages (TSL), which characterizes them as the combination of a strictly local dependency with a tier-projection mechanism that masks out irrelevant segments. Some non-TSL patterns have been pointed out in the literature, though. We show that these outliers can be captured by rendering the tier projection mechanism sensitive to the surrounding structure. We focus on a specific instance of these \textit{structure-sensitive TSL} languages: input-local TSL (ITSL), in which the tier projection may distinguish between identical segments that occur in different local contexts in the input string. This generalization of TSL establishes a tight link between tier-based language classes and ISL transductions, and is motivated by several natural language phenomena.
For the entire collection see [Zbl 1419.68004].Unranked nominal unificationhttps://zbmath.org/1530.681322024-04-15T15:10:58.286558Z"Dundua, Besik"https://zbmath.org/authors/?q=ai:dundua.besik"Kutsia, Temur"https://zbmath.org/authors/?q=ai:kutsia.temur"Rukhaia, Mikheil"https://zbmath.org/authors/?q=ai:rukhaia.mikheilSummary: In this paper we define an unranked nominal language, an extension of the nominal language with tuple variables and term tuples. We define the unification problem for unranked nominal terms and present an algorithm solving the unranked nominal unification problem.
For the entire collection see [Zbl 1494.03010].On the power of generalized forbidding insertion-deletion systemshttps://zbmath.org/1530.681332024-04-15T15:10:58.286558Z"Fernau, Henning"https://zbmath.org/authors/?q=ai:fernau.henning"Kuppusamy, Lakshmanan"https://zbmath.org/authors/?q=ai:kuppusamy.lakshmanan"Raman, Indhumathi"https://zbmath.org/authors/?q=ai:raman.indhumathiSummary: We consider generalized forbidding insertion-deletion systems (GFID) where each insertion-deletion rule is associated with a set \(\mathcal{F}\) of words and the rule can be applied to a string only if every word of \(\mathcal{F}\) is not a subword of the string. The parameters in the size \((k;n,i',i'';m,j',j'')\) of a GFID system denote (from left to right) the maximum length of a word in \(\mathcal{F}\), the maximal length of an insertion string, the maximal length of the left context for insertion, the maximal length of the right context for insertion; the last three parameters follow a similar pattern with respect to deletion. We show that GFID systems of sizes \((k;n,i',i'';m,j',j'')\), where \(k=2\) and \(n+i'+i''=m+j'+j''=2\), with \(n,m>0\) and \(i',i'',j',j''\in \{0,1\}\), describe all recursively enumerable languages, by explaining algorithms that transform a given type-0 grammar in some normal form to a GFID system of the required size.
For the entire collection see [Zbl 1465.68022].On the generative capacity of matrix insertion-deletion systems of small sum-normhttps://zbmath.org/1530.681342024-04-15T15:10:58.286558Z"Fernau, Henning"https://zbmath.org/authors/?q=ai:fernau.henning"Kuppusamy, Lakshmanan"https://zbmath.org/authors/?q=ai:kuppusamy.lakshmanan"Raman, Indhumathi"https://zbmath.org/authors/?q=ai:raman.indhumathiSummary: A matrix insertion-deletion system (or matrix ins-del system) is described by a set of insertion-deletion rules presented in matrix form, which demands all rules of a matrix to be applied in the given order. These systems were introduced to model very simplistic fragments of sequential programs based on insertion and deletion as elementary operations as can be found in biocomputing. We are investigating such systems with limited resources as formalized in descriptional complexity. A traditional descriptional complexity measure of such a matrix ins-del system is its size \(s=(k;n,i',i'';m,j',j'')\), where the parameters from left to right represent the maximal matrix length, maximal insertion string length, maximal length of left contexts in insertion rules, maximal length of right contexts in insertion rules; the last three are deletion counterparts of the previous three parameters. We call the sum \(n+i'+i''+m+j'+j''\) the \textit{sum-norm} of \(s\). We show that matrix ins-del systems of sum-norm 4 and sizes \((3; 1, 0, 0; 1, 2, 0)\), \((3; 1, 0, 0; 1, 0, 2)\), \((2; 1, 2, 0; 1, 0, 0)\), \((2; 1, 0, 2; 1, 0, 0)\), and \((2; 1, 1, 1; 1, 0, 0)\) describe the recursively enumerable languages. Moreover, matrix ins-del systems of sizes \((3; 1, 1, 0; 1, 0, 0)\), \((3; 1, 0, 1; 1, 0, 0)\), \((2; 2, 1, 0; 1, 0, 0)\) and \((2; 2, 0, 1; 1, 0, 0)\) can describe at least the regular closure of the linear languages. In fact, we show that if a matrix ins-del system of size \(s\) can describe the class of linear languages LIN, then without any additional resources, matrix ins-del systems of size \(s\) also describe the regular closure of LIN. Finally, we prove that matrix ins-del systems of sizes \((2; 1, 1, 0; 1, 1, 0)\) and \((2; 1, 0, 1; 1, 0, 1)\) can describe at least the regular languages.Computational completeness of simple semi-conditional insertion-deletion systems of degree (2,1)https://zbmath.org/1530.681352024-04-15T15:10:58.286558Z"Fernau, Henning"https://zbmath.org/authors/?q=ai:fernau.henning"Kuppusamy, Lakshmanan"https://zbmath.org/authors/?q=ai:kuppusamy.lakshmanan"Raman, Indhumathi"https://zbmath.org/authors/?q=ai:raman.indhumathiSummary: Insertion-deletion (or ins-del for short) systems are simple models of bio-inspired computing. They are well studied in formal language theory, especially regarding their computational completeness. This concerns the question if all recursively enumerable languages can be generated. This ultimately addresses the question if one can build general-purpose computers rooted in this formalism. The descriptional complexity of an ins-del system is typically measured by its \textit{size}, a 6-dimensional tuple of non-negative integers \((e,e',e'';d,d',d'')\) where \(e\) is the maximum length of the insertion string, \(e'\) (and \(e'')\) is the maximum length of the left (and right) context used for insertion; the last three parameters \(d,d',d''\) are similarly understood for deletion rules. Computational completeness for ins-del systems can even be achieved with rule size \((1, 1, 1; 1, 1, 1)\) but with no rule size strictly smaller than this. This fact has motivated to study ins-del systems in combination with regulation mechanisms. In this context, the six-tuple explained above is called the \textit{ID size} of a system. Several regulations like graph-control, matrix and semi-conditional have been imposed on ins-del systems. Typically, the computational completeness results are obtained as trade-offs, reducing the ID size, say, to \((1, 1, 0; 1, 1, 0)\) at the expense of increasing other measures of descriptional complexity. In this paper, we study \textit{simple semi-conditional ins-del systems}, where an ins-del rule can be applied only in the presence or absence of substrings of the derivation string. This brings along two further natural parameters to measure descriptional complexity, namely, the maximum permitting string length \(p\) and the maximum forbidden string length \(f\), usually summarized as the degree \(d=(p,f)\). We show that simple semi-conditional ins-del systems of degree \((2, 1)\) and with ID sizes \((1+e,e',e'';1+d,d',d'')\) are computationally complete for any \(e,e',e'',d,d',d''\in \{0,1\} \), with \(e+e'+e''=1\) and \(d+d'+d''=1\). The obtained results complement and improve on the existing results known from the literature. To prove our results, we also show a new normal form for type-0 grammars that appears to be interesting in its own right.Single semi-contextual insertion-deletion systemshttps://zbmath.org/1530.681362024-04-15T15:10:58.286558Z"Ivanov, Sergiu"https://zbmath.org/authors/?q=ai:ivanov.sergiu"Verlan, Sergey"https://zbmath.org/authors/?q=ai:verlan.sergeySummary: In this paper we consider the model of single insertion-deletion systems that at each step insert or delete a single symbol in a context-free manner (i.e. at any position in the word). The corresponding operation is performed if the word contains a set of permitting (that have to be present in the word) and/or forbidding (that must not be present in the word) strings of some size. The main result of this paper states that if forbidding strings of size 2 and permitting strings of size 1 are used then computational completeness can be achieved; moreover, checking for a single permitting symbol is sufficient. We also show that in the case of systems having rules with forbidding conditions only, all regular languages can be obtained. Finally, we show the computational non-completeness in the case of systems using rules with forbidding strings of size 1 (single symbols) and permitting strings of any finite size.On the computational complexity of head movement and affix hoppinghttps://zbmath.org/1530.681372024-04-15T15:10:58.286558Z"Stanojević, Miloš"https://zbmath.org/authors/?q=ai:stanojevic.milosSummary: Head movement is a syntactic operation used in most generative syntactic analyses. However, its computational properties have not been extensively studied. [\textit{E. P. Stabler}, Lect. Notes Comput. Sci. 2099, 245--260 (2001; Zbl 0990.03511)] formalises head movement in the framework of Minimalist Grammars by extending the item representation to allow for easy extraction of the head. This work shows that Stabler's representation is in fact suboptimal because it causes higher polynomial parsing complexity. A new algorithm is derived for parsing head movement and affix hopping by changing the kinds of representations that the parser deals with. This algorithm has much better asymptotic worst-case runtime of \(\mathcal{O}(n^{2k+5})\). This result makes parsing head movement and affix hopping computationally as efficient as parsing a single phrase movement.
For the entire collection see [Zbl 1419.68004].Insertion-deletion systems with substitutions. Ihttps://zbmath.org/1530.681382024-04-15T15:10:58.286558Z"Vu, Martin"https://zbmath.org/authors/?q=ai:vu.martin"Fernau, Henning"https://zbmath.org/authors/?q=ai:fernau.henningSummary: With good biological motivation, we add substitutions as a further type of operations to (in particular, context-free) insertion-deletion systems. This way, we obtain new characterizations of and normal forms for context-sensitive and recursively enumerable languages.
For Parts II and III see [the authors, ibid. 12442, 231--243 (2020; Zbl 1490.68131); ibid. 12607, 577--592 (2021; Zbl 1490.68133)].
For the entire collection see [Zbl 1502.68017].Hairpin completions and reductions: semilinearity propertieshttps://zbmath.org/1530.681392024-04-15T15:10:58.286558Z"Bordihn, Henning"https://zbmath.org/authors/?q=ai:bordihn.henning"Mitrana, Victor"https://zbmath.org/authors/?q=ai:mitrana.victor"Păun, Andrei"https://zbmath.org/authors/?q=ai:paun.andrei"Păun, Mihaela"https://zbmath.org/authors/?q=ai:paun.mihaelaSummary: This paper is part of the investigation of some operations on words and languages with motivations coming from DNA biochemistry, namely three variants of hairpin completion and three variants of hairpin reduction. Since not all the hairpin completions or reductions of semilinear languages remain semilinear, we study sufficient conditions for semilinear languages to preserve their semilinearity property after applying the non-iterated hairpin completion or hairpin reduction. A similar approach is then applied to the iterated variants of these operations. Along these lines, we define the hairpin reduction root of a language and show that the hairpin reduction root of a semilinear language is not necessarily semilinear except the universal language. A few open problems are finally discussed.Bar-Hillel theorem mechanization in Coqhttps://zbmath.org/1530.681402024-04-15T15:10:58.286558Z"Bozhko, Sergey"https://zbmath.org/authors/?q=ai:bozhko.sergey"Khatbullina, Leyla"https://zbmath.org/authors/?q=ai:khatbullina.leyla"Grigorev, Semyon"https://zbmath.org/authors/?q=ai:grigorev.semyonSummary: Formal language theory has a deep connection with such areas as static code analysis, graph database querying, formal verification, and compressed data processing. Many application problems can be formulated in terms of languages intersection. The Bar-Hillel theorem states that context-free languages are closed under intersection with a regular set. This theorem has a constructive proof and thus provides a formal justification of correctness of the algorithms for applications mentioned above. Mechanization of the Bar-Hillel theorem, therefore, is both a fundamental result of formal language theory and a basis for the certified implementation of the algorithms for applications. In this work, we present the mechanized proof of the Bar-Hillel theorem in Coq.
For the entire collection see [Zbl 1418.03008].Commutative automata networkshttps://zbmath.org/1530.681412024-04-15T15:10:58.286558Z"Bridoux, Florian"https://zbmath.org/authors/?q=ai:bridoux.florian"Gadouleau, Maximilien"https://zbmath.org/authors/?q=ai:gadouleau.maximilien"Theyssier, Guillaume"https://zbmath.org/authors/?q=ai:theyssier.guillaumeSummary: Automata networks are mappings of the form \(f: Q^Z \rightarrow Q^Z\), where \(Q\) is a finite alphabet and \(Z\) is a set of entities; they generalise Cellular Automata and Boolean networks. An update schedule dictates when each entity updates its state according to its local function \(f_i: Q^Z \rightarrow Q\). One major question is to study the behaviour of a given automata networks under different update schedules. In this paper, we study automata networks that are invariant under many different update schedules. This gives rise to two definitions, locally commutative and globally commutative networks. We investigate the relation between commutativity and different forms of locality of update functions; one main conclusion is that globally commutative networks have strong dynamical properties, while locally commutative networks are much less constrained. We also give a complete classification of all globally commutative Boolean networks.
For the entire collection see [Zbl 1464.68024].On simulation in automata networkshttps://zbmath.org/1530.681422024-04-15T15:10:58.286558Z"Bridoux, Florian"https://zbmath.org/authors/?q=ai:bridoux.florian"Gadouleau, Maximilien"https://zbmath.org/authors/?q=ai:gadouleau.maximilien"Theyssier, Guillaume"https://zbmath.org/authors/?q=ai:theyssier.guillaumeSummary: An automata network is a finite graph where each node holds a state from some finite alphabet and is equipped with an update function that changes its state according to the configuration of neighboring states. More concisely, it is given by a finite map \(f:Q^n\rightarrow Q^n\). In this paper we study how some (sets of) automata networks can be simulated by some other (set of) automata networks with prescribed update mode or interaction graph. Our contributions are the following. For non-Boolean alphabets and for any network size, there are intrinsically non-sequential transformations (i.e. that can not be obtained as composition of sequential updates of some network). Moreover there is no universal automaton network that can produce all non-bijective functions via compositions of asynchronous updates. On the other hand, we show that there are universal automata networks for sequential updates if one is allowed to use a larger alphabet and then use either projection onto or restriction to the original alphabet. We also characterize the set of functions that are generated by non-bijective sequential updates. Following Tchuente, we characterize the interaction graphs \(D\) whose semigroup of transformations is the full semigroup of transformations on \(Q^n\), and we show that they are the same if we force either sequential updates only, or all asynchronous updates.
For the entire collection see [Zbl 1502.68017].Characterizing the decidability of finite state automata team games with communicationhttps://zbmath.org/1530.681432024-04-15T15:10:58.286558Z"Coulombe, Michael"https://zbmath.org/authors/?q=ai:coulombe.michael-j"Lynch, Jayson"https://zbmath.org/authors/?q=ai:lynch.jaysonSummary: In this paper we define a new model of limited communication for multiplayer team games of imperfect information. We prove that the Team DFA Game and Team Formula Game, which have bounded state, remain undecidable when players have a rate of communication which is less than the rate at which they make moves in the game. We also show that meeting this communication threshold causes these games to be decidable.
For the entire collection see [Zbl 1522.68028].About block-parallel Boolean networks: a position paperhttps://zbmath.org/1530.681442024-04-15T15:10:58.286558Z"Demongeot, Jacques"https://zbmath.org/authors/?q=ai:demongeot.jacques"Sené, Sylvain"https://zbmath.org/authors/?q=ai:sene.sylvainSummary: In automata networks, it is well known that the way entities update their states over time has a major impact on their dynamics. In particular, depending on the chosen update schedule, the underlying dynamical systems may exhibit more or less asymptotic dynamical behaviours such as fixed points or limit cycles. Since such mathematical models have been used in the framework of biological networks modelling, the question of choosing appropriate update schedules has arised soon. In this note, focusing on Boolean networks, our aim is to emphasise that the adequate way of thinking regulations and genetic expression over time is certainly not to consider a wall segregating synchronicity from asynchronicity because they actually complement rather well. In particular, we highlight that specific update schedules, namely block-parallel update schedules, whose intrinsic features are still not known from a theoretical point of view, admit realistic and pertinent properties in the context of biological modelling and deserve certainly more attention from the community.Generating tokenizers with flat automatahttps://zbmath.org/1530.681452024-04-15T15:10:58.286558Z"De Nivelle, Hans"https://zbmath.org/authors/?q=ai:de-nivelle.hans"Muktubayeva, Dina"https://zbmath.org/authors/?q=ai:muktubayeva.dinaSummary: We introduce flat automata for automatic generation of tokenizers. Flat automata are a simple representation of standard finite automata. Using the flat representation, automata can be easily constructed, combined and printed. Due to the use of border functions, flat automata are more compact than standard automata in the case where intervals of characters are attached to transitions, and the standard algorithms on automata are simpler. We give the standard algorithms for tokenizer construction with automata, namely construction using regular operations, determinization, and minimization. We prove their correctness. The algorithms work with intervals of characters, but are not more complicated than their counterparts on single characters. It is easy to generate C++ code from the final deterministic automaton. All procedures have been implemented in C++ and are publicly available. The implementation has been used in applications and in teaching.
For the entire collection see [Zbl 1522.68028].The effect of jumping modes on various automata modelshttps://zbmath.org/1530.681462024-04-15T15:10:58.286558Z"Fazekas, Szilárd Zsolt"https://zbmath.org/authors/?q=ai:fazekas.szilard-zsolt"Hoshi, Kaito"https://zbmath.org/authors/?q=ai:hoshi.kaito"Yamamura, Akihiro"https://zbmath.org/authors/?q=ai:yamamura.akihiroSummary: Recently, new types of non-sequential machine models have been introduced and studied, such as jumping automata and one-way jumping automata. We study the abilities and limitations of (finite, pushdown and linear bounded) automata with these 2 jumping modes of tape heads with respect to how they affect the class of accepted languages. We provide adapted versions of pumping lemmas and other methods to determine whether a language is accepted by a machine with jumping mode. Using these methods we establish the inclusion or incomparability relationships among the classes of languages defined by the new machines and their classical counterparts. We also study the closure properties of the resulting language classes and show that under most fundamental language operations, these classes are not closed.On the impact of treewidth in the computational complexity of freezing dynamicshttps://zbmath.org/1530.681472024-04-15T15:10:58.286558Z"Goles, Eric"https://zbmath.org/authors/?q=ai:goles-chacc.eric"Montealegre, Pedro"https://zbmath.org/authors/?q=ai:montealegre.pedro"Ríos Wilson, Martín"https://zbmath.org/authors/?q=ai:rios-wilson.martin"Theyssier, Guillaume"https://zbmath.org/authors/?q=ai:theyssier.guillaumeSummary: An automata network is a network of entities, each holding a state from a finite set and evolving according to a local update rule which depends only on its neighbors in the network's graph. It is freezing if there is an order on states such that the state evolution of any node is non-decreasing in any orbit. They are commonly used to model epidemic propagation, diffusion phenomena like bootstrap percolation or cristal growth. In this paper we establish how alphabet size, treewidth and maximum degree of the underlying graph are key parameters which influence the overall computational complexity of finite freezing automata networks. First, we define a general specification checking problem that captures many classical decision problems such as prediction, nilpotency, predecessor, asynchronous reachability. Then, we present a fast-parallel algorithm that solves the general problem when the three parameters are bounded, hence showing that the problem is in \textbf{NC}. Finally, we show that these problems are hard from two different perspectives. First, the general problem is \textbf{W}[2]-hard when taking either treewidth or alphabet as single parameter and fixing the others. Second, the classical problems are hard in their respective classes when restricted to families of graphs with sufficiently large treewidth.
For the entire collection see [Zbl 1482.68017].Computational limitations of affine automata and generalized affine automatahttps://zbmath.org/1530.681482024-04-15T15:10:58.286558Z"Hirvensalo, Mika"https://zbmath.org/authors/?q=ai:hirvensalo.mika"Moutot, Etienne"https://zbmath.org/authors/?q=ai:moutot.etienne"Yakaryılmaz, Abuzer"https://zbmath.org/authors/?q=ai:yakaryilmaz.abuzerSummary: We present new results on the computational limitations of affine automata (AfAs). First, we show that using the endmarker does not increase the computational power of AfAs. Second, we show that the computation of bounded-error rational-valued AfAs can be simulated in logarithmic space. Third, we identify some logspace unary languages that are not recognized by algebraic-valued AfAs. Fourth, we show that using arbitrary real-valued transition matrices and state vectors does not increase the computational power of AfAs in the unbounded-error model. When focusing only the rational values, we obtain the same result also for bounded error. As a consequence, we show that the class of bounded-error affine languages remains the same when the AfAs are restricted to use rational numbers only.Correction to: ``Computational limitations of affine automata and generalized affine automata''https://zbmath.org/1530.681492024-04-15T15:10:58.286558Z"Hirvensalo, Mika"https://zbmath.org/authors/?q=ai:hirvensalo.mika"Moutot, Etienne"https://zbmath.org/authors/?q=ai:moutot.etienne"Yakaryılmaz, Abuzer"https://zbmath.org/authors/?q=ai:yakaryilmaz.abuzerSummary: In the original publication of the authors' article [ibid. 20, No. 2, 259--270 (2021; Zbl 1530.68148)], unfortunately, the corrections provided were missed for affiliations, equations and sentences. The original article has been updated with the corrections.Solving word equations (and other unification problems) by recompression (invited talk)https://zbmath.org/1530.681502024-04-15T15:10:58.286558Z"Jeż, Artur"https://zbmath.org/authors/?q=ai:jez.arturSummary: In word equation problem we are given an equation \(u=v\), where both \(u\) and \(v\) are words of letters and variables, and ask for a substitution of variables by words that equalizes the sides of the equation. This problem was first solved by Makanin and a different solution was proposed by Plandowski only 20 years later, his solution works in PSPACE, which is the best computational complexity bound known for this problem; on the other hand, the only known lower-bound is NP-hardness. In both cases the algorithms (and proofs) employed nontrivial facts on word combinatorics.\par In the paper I will present an application of a recent technique of recompression, which simplifies the known proofs and (slightly) lowers the complexity to linear nondeterministic space. The technique is based on employing simple compression rules (replacement of two letters \(ab\) by a new letter \(c\), replacement of maximal repetitions of \(a\) by a new letter), and modifying the equations (replacing a variable \(X\) by \(bX\) or \(Xa\)) so that those operations are sound and complete. In particular, no combinatorial properties of strings are used.\par The approach turns out to be quite robust and can be applied to various generalizations and related scenarios (context unification, i.e. equations over terms; equations over traces, i.e. partially ordered words; \dots).
For the entire collection see [Zbl 1434.68025].State-deterministic \(5'\rightarrow 3'\) Watson-Crick automatahttps://zbmath.org/1530.681512024-04-15T15:10:58.286558Z"Nagy, Benedek"https://zbmath.org/authors/?q=ai:nagy.benedekSummary: Watson-Crick (WK) finite automata are working on a Watson-Crick tape, that is, on a DNA molecule. Therefore, they have two reading heads, one for each strand. In traditional WK automata both heads read the whole input in the same physical direction, but in \(5'\rightarrow 3'\) WK automata the heads start from the two extremes and read the input in opposite direction. In sensing \(5'\rightarrow 3'\) WK automata the process on the input is finished when the heads meet, and the model characterise the linear context-free languages. Deterministic variants are weaker, the class 2detLIN is accepted by them. In this paper a new concept, the state-determinism is investigated, that is in each configuration of a computation (if it is not finished yet) the next state is determined by the actual state of the configuration. There are various usual restrictions on WK automata, e.g., all-final, stateless or 1-limited variants. We place the new class, the state-deterministic \(5'\rightarrow 3'\) WK automata, into the hierarchy based on the accepted language classes. Further, various hierarchy results including combined restrictions, e.g., 1-limited all-final state-deterministic \(5'\rightarrow 3'\) WK automata are shown.\(5'\rightarrow 3'\) Watson-Crick automata languages-without sensing parameterhttps://zbmath.org/1530.681522024-04-15T15:10:58.286558Z"Nagy, Benedek"https://zbmath.org/authors/?q=ai:nagy.benedek"Parchami, Shaghayegh"https://zbmath.org/authors/?q=ai:parchami.shaghayeghSummary: Watson-Crick (WK) finite automata are working on a Watson-Crick tape, that is, on an abstract construct similar to DNA molecules. Therefore, it has two reading heads. While in traditional WK automata both heads read the whole input in the same physical direction, in \(5'\rightarrow 3'\) WK automata the heads start from the two extremes and read the input in opposite direction. In sensing \(5'\rightarrow 3'\) WK automata the process on the input is finished when the heads meet. Since the heads of a WK automaton may read longer strings in a transition, in previous models a so-called sensing parameter took care for the proper meeting of the heads (not allowing to read the same positions of the input in the last step). In this paper, a new model is investigated, which works without the sensing parameter (it is done by an appropriate change of the concept of configuration). Consequently, the accepted language classes of the variants are also changed. Various hierarchy results including six sublinear language classes and closure properties are proven in the paper.Schema-based automata determinizationhttps://zbmath.org/1530.681532024-04-15T15:10:58.286558Z"Niehren, Joachim"https://zbmath.org/authors/?q=ai:niehren.joachim"Sakho, Momar"https://zbmath.org/authors/?q=ai:sakho.momar"Al Serhali, Antonio"https://zbmath.org/authors/?q=ai:serhali.antonio-alSummary: We propose an algorithm for schema-based determinization of finite automata on words and of step-wise hedge automata on nested words. The idea is to integrate schema-based cleaning directly into automata determinization. We prove the correctness of our new algorithm and show that it is always more efficient than standard determinization followed by schema-based cleaning. Our implementation permits to obtain a small deterministic automaton for an example of an XPath query, where standard determinization yields a huge stepwise hedge automaton for which schema-based cleaning runs out of memory.
For the entire collection see [Zbl 1522.68028].Grounding game semantics in categorical algebrahttps://zbmath.org/1530.681542024-04-15T15:10:58.286558Z"Koenig, Jérémie"https://zbmath.org/authors/?q=ai:koenig.jeremieSummary: I present a formal connection between \textit{algebraic effects} and \textit{game semantics}, two important lines of work in programming languages semantics with applications in compositional software verification.
Specifically, the algebraic signature enumerating the possible side-effects of a computation can be read as a game, and strategies for this game constitute the free algebra for the signature in a category of complete partial orders (\textit{cpos}). Hence, strategies provide a convenient model of computations with uninterpreted side-effects. In particular, the operational flavor of game semantics carries over to the algebraic context, in the form of the coincidence between the initial algebras and the terminal coalgebras of cpo endofunctors.
Conversely, the algebraic point of view sheds new light on the strategy constructions underlying game semantics. Strategy models can be reformulated as ideal completions of partial strategy trees (free dcpos on the term algebra). Extending the framework to multi-sorted signatures would make this construction available for a large class of games.
For the entire collection see [Zbl 1522.68034].Parametric interval temporal logic over infinite wordshttps://zbmath.org/1530.681552024-04-15T15:10:58.286558Z"Bozzelli, Laura"https://zbmath.org/authors/?q=ai:bozzelli.laura"Peron, Adriano"https://zbmath.org/authors/?q=ai:peron.adrianoSummary: Model checking for Halpern and Shoham's interval temporal logic \textsf{HS} has been recently investigated in a systematic way, and it is known to be decidable under three distinct semantics. Here, we focus on the \textit{trace-based semantics}, where the infinite execution paths (traces) of the given (finite) Kripke structure are the main semantic entities. In this setting, each finite infix of a trace is interpreted as an interval, and a proposition holds over an interval if and only if it holds over each component state (\textit{homogeneity assumption}). In this paper, we introduce a quantitative extension of \textsf{HS} over traces, called \textit{parametric} \textsf{HS} (\textsf{PHS}). The novel logic allows to express parametric timing constraints on the duration (length) of the intervals. We show that checking the existence of a parameter valuation for which a Kripke structure satisfies a \textsf{PHS} formula (model checking), or a \textsf{PHS} formula admits a trace as a model under the homogeneity assumption (satisfiability) is decidable. Moreover, we identify a fragment of \textsf{PHS} which subsumes parametric \textsf{LTL} and for which model checking and satisfiability are shown to be \textsc{Expspace}-complete.
For the entire collection see [Zbl 1522.68028].I/O automata in Isabelle/HOLhttps://zbmath.org/1530.681562024-04-15T15:10:58.286558Z"Nipkow, Tobias"https://zbmath.org/authors/?q=ai:nipkow.tobias"Slind, Konrad"https://zbmath.org/authors/?q=ai:slind.konradSummary: We have embedded the meta-theory of I/O automata, a model for describing and reasoning about distributed systems, in Isabelle's version of higher order logic. On top of that, we have specified and verified a recent network transmission protocol which achieves reliable communication using single-bit-header packets over a medium which may reorder packets arbitrarily.
For the entire collection see [Zbl 0866.00037].Algebraic properties of implication-based intuitionistic fuzzy finite state machine over a finite grouphttps://zbmath.org/1530.681572024-04-15T15:10:58.286558Z"Selvarathi, M."https://zbmath.org/authors/?q=ai:selvarathi.mSummary: An extensive study is performed on the already constituted algebraic structure called the \textit{implication-based intuitionistic fuzzy semiautomaton} (IB-IFSA) over a finite group that compromises of \textit{implication-based intuitionistic fuzzy kernel} and \textit{implication-based intuitionistic fuzzy subsemiautomaton}. In this paper, the necessary and sufficient condition for an \textit{implication-based intuitionistic fuzzy normal subgroup} to be an \textit{implication-based intuitionistic fuzzy kernel} of an \textit{implication-based intuitionistic fuzzy semiautomaton} is developed. In addition, the fundamental and adequate condition for an \textit{implication-based intuitionistic fuzzy subgroup} to be an \textit{implication-based intuitionistic fuzzy subsemiautomaton} of an IB-IFSA is formulated. Moreover, the condition for an \textit{implication-based intuitionistic fuzzy kernel} of the an IB-IFSA to be \textit{implication-based intuitionistic fuzzy subsemiautomaton} is also established.A survey of cellular automata: types, dynamics, non-uniformity and applicationshttps://zbmath.org/1530.681582024-04-15T15:10:58.286558Z"Bhattacharjee, Kamalika"https://zbmath.org/authors/?q=ai:bhattacharjee.kamalika"Naskar, Nazma"https://zbmath.org/authors/?q=ai:naskar.nazma-n"Roy, Souvik"https://zbmath.org/authors/?q=ai:roy.souvik.1"Das, Sukanta"https://zbmath.org/authors/?q=ai:das.sukantaSummary: Cellular automata (CAs) are dynamical systems which exhibit complex global behavior from simple local interaction and computation. Since the inception of cellular automaton (CA) by von Neumann in 1950s, it has attracted the attention of several researchers over various backgrounds and fields for modeling different physical, natural as well as real-life phenomena. Classically, CAs are uniform. However, non-uniformity has also been introduced in update pattern, lattice structure, neighborhood dependency and local rule. In this survey, we tour to the various types of CAs introduced till date, the different characterization tools, the global behavior of CAs, like universality, reversibility, dynamics etc. Special attention is given to non-uniformity in CAs and especially to non-uniform elementary CAs, which have been very useful in solving several real-life problems.Communication complexity meets cellular automata: necessary conditions for intrinsic universalityhttps://zbmath.org/1530.681592024-04-15T15:10:58.286558Z"Briceño, Raimundo"https://zbmath.org/authors/?q=ai:briceno.raimundo"Rapaport, Ivan"https://zbmath.org/authors/?q=ai:rapaport.ivanSummary: A natural way to interpret a cellular automaton (CA) is as a mechanism that computes, in a distributed way, some function \(f\). In other words, from a computer science point of view, CAs can be seen as distributed systems where the cells of the CAs are nodes of a network linked by communication channels. A classic measure of efficiency in such distributed systems is the number of bits exchanged during the computation process. A typical approach is to look for bottlenecks: channels through which the nature of the function \(f\) forces the exchange of a significant number of bits. In practice, a widely used way to understand such congestion phenomena is to partition the system into two subsystems and try to find bounds for the number of bits that \textit{must} pass through the channels that join them. Finding these bounds is the focus of communication complexity theory. Measuring the communication complexity of some problems induced by a CA \(\phi\) turned out to be tremendously useful to give clues regarding the intrinsic universality of \(\phi \) (a CA is said to be intrinsically universal if it is capable of emulating any other). In fact, there exist particular problems \(\mathrm{P} \)'s for which the following key property holds: if \(\phi\) is intrinsically universal, then the communication complexity of \(\mathrm{P}(\phi )\) must be maximal. In this tutorial, we intend to explain the connections that were found, through a series of papers, between intrinsic universality and communication complexity in CAs.Cellular automata and finite groupshttps://zbmath.org/1530.681602024-04-15T15:10:58.286558Z"Castillo-Ramirez, Alonso"https://zbmath.org/authors/?q=ai:castillo-ramirez.alonso"Gadouleau, Maximilien"https://zbmath.org/authors/?q=ai:gadouleau.maximilienSummary: For a finite group \(G\) and a finite set \(A\), we study various algebraic aspects of cellular automata over the configuration space \(A^G\). In this situation, the set \(\operatorname{CA}(G;A)\) of all cellular automata over \(A^G\) is a finite monoid whose basic algebraic properties had remained unknown. First, we investigate the structure of the group of units \(\operatorname{ICA}(G;A)\) of \(\operatorname{CA}(G;A)\). We obtain a decomposition of \(\operatorname{ICA}(G;A)\) into a direct product of wreath products of groups that depends on the numbers \(\alpha_{[H]}\) of periodic configurations for conjugacy classes \([H]\) of subgroups of \(G\). We show how the numbers \(\alpha_{[H]}\) may be computed using the Möbius function of the subgroup lattice of \(G\), and we use this to improve the lower bound recently found by Gao, Jackson and Seward on the number of aperiodic configurations of \(A^G\). Furthermore, we study generating sets of \(\operatorname{CA}(G;A)\); in particular, we prove that \(\operatorname{CA}(G;A)\) cannot be generated by cellular automata with small memory set, and, when all subgroups of \(G\) are normal, we determine the relative rank of \(\operatorname{ICA}(G;A)\) on \(\operatorname{CA}(G;A)\), i.e. the minimal size of a set \(V \subseteq \operatorname{CA}(G;A)\) such that \(\operatorname{CA}(G;A) = \langle \operatorname{ICA}(G;A) \cup V \rangle \).On multi-rule and probability-dependent adaptations of Conway's game of life and their characterhttps://zbmath.org/1530.681612024-04-15T15:10:58.286558Z"Cotronei, Alessandro"https://zbmath.org/authors/?q=ai:cotronei.alessandroSummary: We introduce some novel adaptations of Life-Like Automata. We focus mainly on some modifications of the original rules where the evolution of the system is depending from the step and the zone of the grid. We study also the properties of some novel non-deterministic adaptations.Game of life, Athenian democracy and computationhttps://zbmath.org/1530.681622024-04-15T15:10:58.286558Z"Das, Sukanta"https://zbmath.org/authors/?q=ai:das.sukantaSummary: This article revisits John Conway's Game-of-Life from the view point of democratic systems. We argue that the democracy followed by Game-of-Life is a kind of direct democracy, which was first successfully practiced in the city state of Athens of ancient Greece. We compare two apparently dissimilar entities from abstract point of view -- Game-of-Life which is a computational system and Athenian democracy, and point out their similarities and dissimilarities. To deal with the dissimilarities, we also outline a model of computation. We also indicate that the Cellular Automata with Memory can address the dissimilarities to some extent.
For the entire collection see [Zbl 1491.11006].Correction to: ``A class of discrete dynamical systems with properties of both cellular automata and L-systems''https://zbmath.org/1530.681632024-04-15T15:10:58.286558Z"Edwards, Roderick"https://zbmath.org/authors/?q=ai:edwards.roderick"Maignan, Aude"https://zbmath.org/authors/?q=ai:maignan.audeFrom the text: In the pdf version of the original publication [the authors, ibid. 19, No. 3, 609--641 (2020; Zbl 1530.68164)], in the proof of Theorem 8 (second column of p. 632), the \(T\) matrices appeared incorrectly. The correct values are given here.A class of discrete dynamical systems with properties of both cellular automata and L-systemshttps://zbmath.org/1530.681642024-04-15T15:10:58.286558Z"Edwards, Roderick"https://zbmath.org/authors/?q=ai:edwards.roderick"Maignan, Aude"https://zbmath.org/authors/?q=ai:maignan.audeSummary: We introduce and explore a type of discrete dynamic system inheriting some properties of both cellular automata (CA) and L-systems. Originally suggested by Jean Della Dora, and thus called DEM-systems after him and the two current authors, these systems can have the structural flexibility of an L-system as well as algebraic properties of CA. They are defined as sequences on a one-dimensional loop with rules governing dynamics in which new sites can be created, depending on the states of a neighbourhood of sites, and complex behaviour can be generated. Although the definition of DEM-systems is quite broad, we define some subclasses, for which more complete results can be obtained. For example, we define an additive subclass, for which algebraic results on asymptotic growth are possible, and an elementary class of particularly simple rules, for which nevertheless impressive complexity is achievable. Unlike for CA, finite initial sequences can produce positive spatial entropy over time. However, even in cases where the entropy is zero, considerable complexity is possible, especially when the sequence length grows to infinity, and we demonstrate and study behaviours of DEM-systems including fragmentation of sequences, self-reproducing patterns, self-similar but irregular patterns, patterns that not only produce new sites but produce producers of new sites, and sequences whose growth rate is sublinear, linear, quadratic, cubic, or exponential. The most complex behaviour from small finite initial conditions and the simplest class of rules appear to have positive entropy, a suggestion for which we have so far only stong numerical evidence, though we present a proof for these `elementary' DEM-systems that entropy cannot reach the theoretical maximum of 1.Remarks on the cellular automaton global synchronisation problem: deterministic versus stochastic modelshttps://zbmath.org/1530.681652024-04-15T15:10:58.286558Z"Fatès, Nazim"https://zbmath.org/authors/?q=ai:fates.nazim-aSummary: In the global synchronisation problem, one is asked to find a cellular automaton which has the property that every initial condition evolves into a homogeneous blinking state. We study this simple inverse problem for the case of one-dimensional systems with periodic boundary conditions. Two paradoxical observations are made: (a) despite the apparent simplicity of finding rules with good statistical results, there exist no perfect deterministic solutions to this problem, (b) if we allow the use of randomness in the local rule, constructing ``perfect'' stochastic solutions is easy. For the stochastic case, we give some rules for which the mean time of synchronisation varies quadratically with the number of cells and ask if this result can be improved. To explore more deeply the deterministic rules, we code our problem as a SAT problem and use SAT solvers to find rules that synchronise a large set of initial conditions (in appendix).Cellular automata rules solving the wireless sensor network coverage problemhttps://zbmath.org/1530.681662024-04-15T15:10:58.286558Z"Hoffmann, Rolf"https://zbmath.org/authors/?q=ai:hoffmann.rolf"Désérable, Dominique"https://zbmath.org/authors/?q=ai:deserable.dominique"Seredyński, Franciszek"https://zbmath.org/authors/?q=ai:seredynski.franciszekSummary: The problem of an optimal coverage of a wireless sensor network area is considered. To solve this problem, a Cellular Automata (CA) approach is proposed. More specifically, the objective is to find CA rules which are able to cover the 2D space by a minimum number of so-called ``Sensor Tiles''. A sensor tile consists of a von Neumann neighborhood of range 2 centered at sensor ``point'' and surrounded by 12 sensing ``pixels''. Two probabilistic CA rules were designed that can perform this task. Results of an experimental study show that the first rule evolves very fast stable sub-optimal coverings, starting from a random configuration. The second rule finds optimal coverings, however it needs much more time for their evolution. The results are supported by a theoretical study on von Neumann neighborhoods and borrowing either from heuristics or from the spectral theory of circulant graphs.Covering the space with sensor tileshttps://zbmath.org/1530.681672024-04-15T15:10:58.286558Z"Hoffmann, Rolf"https://zbmath.org/authors/?q=ai:hoffmann.rolf"Seredyński, Franciszek"https://zbmath.org/authors/?q=ai:seredynski.franciszekSummary: The objective is to find Cellular Automata (CA) which are able to cover the 2D space by a minimum number of so-called ``Sensor Tiles''. A sensor tile consists of a central sensor pixel and 12 surrounding sensing pixels. Two probabilistic CA rules were designed that can perform this task. The first rule evolves very fast stable sub-optimal coverings, starting from a random configuration. The second rule finds several optimal or near-optimal coverings but needs much more time for their evolution.
For the entire collection see [Zbl 1482.68024].Simulation of non-uniform cellular automata by classical cellular automata and its application in embedded systemshttps://zbmath.org/1530.681682024-04-15T15:10:58.286558Z"Kamilya, Supreeti"https://zbmath.org/authors/?q=ai:kamilya.supreeti"Das, Sukanta"https://zbmath.org/authors/?q=ai:das.sukanta"Sikdar, Biplab K."https://zbmath.org/authors/?q=ai:sikdar.biplab-kSummary: A uniform cellular automaton (CA) is a special case of non-uniform CA. This paper shows that for any non-uniform CA, there exists a uniform CA that simulates the dynamics of the non-uniform CA. A function \((\psi)\) is defined that maps the rules and states of a non-uniform CA to the states of the proposed uniform CA. According to the construction of the function, the number of states of the uniform CA is greater than that of the non-uniform CA. It is shown that, a number of non-uniform cellular automata (CAs), formed using same set of local rules, can be simulated by a single uniform CA. Under this construction, the function \(\psi\) is a bijection. To reduce the number of states in the uniform CA, the function \(\psi\) is redefined later as a non-bijective function. However, there exists some uniform CAs which do not simulate any non-uniform CA by the given construction. As any non-uniform CA can be simulated by uniform CA, different applications that use different non-uniform CAs, can now be implemented in one system. This paper shows a brief overview of such an application. The proposed CA based design ensures hardware re-usability and cost effectiveness.Sequentializing cellular automatahttps://zbmath.org/1530.681692024-04-15T15:10:58.286558Z"Kari, Jarkko"https://zbmath.org/authors/?q=ai:kari.jarkko"Salo, Ville"https://zbmath.org/authors/?q=ai:salo.ville-o"Worsch, Thomas"https://zbmath.org/authors/?q=ai:worsch.thomasSummary: We study the problem of sequentializing a cellular automaton without introducing any intermediate states, and only performing reversible permutations on the tape. We give a decidable characterization of cellular automata which can be written as a single sweep of a bijective rule from left to right over an infinite tape. Such cellular automata are necessarily left-closing, and they move at least as much information to the left as they move information to the right.On computing the Lyapunov exponents of reversible cellular automatahttps://zbmath.org/1530.681702024-04-15T15:10:58.286558Z"Kopra, Johan"https://zbmath.org/authors/?q=ai:kopra.johanSummary: We consider the problem of computing the Lyapunov exponents of reversible cellular automata (CA). We show that the class of reversible CA with right Lyapunov exponent 2 cannot be separated algorithmically from the class of reversible CA whose right Lyapunov exponents are at most \(2-\delta\) for some absolute constant \(\delta >0\). Therefore there is no algorithm that, given as an input a description of an arbitrary reversible CA \(F\) and a positive rational number \(\epsilon >0\), outputs the Lyapunov exponents of \(F\) with accuracy \(\epsilon \). We also compute the average Lyapunov exponents (with respect to the uniform measure) of the reversible CA that perform multiplication by \(p\) in base \textit{pq} for coprime \(p,q>1\).Iterative arrays with self-verifying communication cellhttps://zbmath.org/1530.681712024-04-15T15:10:58.286558Z"Kutrib, Martin"https://zbmath.org/authors/?q=ai:kutrib.martinSummary: We study the computational capacity of self-verifying iterative arrays (SVIA). A self-verifying device is a nondeterministic device whose nondeterminism is symmetric in the following sense. Each computation path can give one of the answers \textit{yes}, \textit{no}, or \textit{do not know}. For every input word, at least one computation path must give either the answer \textit{yes} or \textit{no}, and the answers given must not be contradictory. It turns out that, for any time-computable time complexity, the family of languages accepted by SVIAs is a characterization of the so-called complementation kernel of nondeterministic iterative array languages, that is, languages accepted by such devices whose complementation is also accepted by such devices. SVIAs can be sped-up by any constant multiplicative factor as long as the result does not fall below realtime. We show that even realtime SVIA are as powerful as lineartime self-verifying cellular automata and vice versa. So they are strictly more powerful than the deterministic devices. Closure properties and various decidability problems are considered.One-dimensional pattern generation by cellular automatahttps://zbmath.org/1530.681722024-04-15T15:10:58.286558Z"Kutrib, Martin"https://zbmath.org/authors/?q=ai:kutrib.martin"Malcher, Andreas"https://zbmath.org/authors/?q=ai:malcher.andreasSummary: To determine the computational capacity of cellular automata they are often investigated towards their ability to accept formal languages within certain time constraints. In this paper, we take up an opposite position and look at cellular automata towards their ability to \textit{generate} patterns, within certain time constraints. As an example we describe a construction of a cellular automaton that generates prefixes of the Oldenburger-Kolakoski sequence within real time. Furthermore, we study the real-time generation of unary and non-unary patterns in depth. In the unary case, we obtain a characterization by time-constructible functions and their corresponding unary formal languages. In the non-unary case, we provide constructions that generate any arbitrary given properly thin context-free language as well as all prefixes of any given automatic sequence.Iterative arrays with finite inter-cell communicationhttps://zbmath.org/1530.681732024-04-15T15:10:58.286558Z"Kutrib, Martin"https://zbmath.org/authors/?q=ai:kutrib.martin"Malcher, Andreas"https://zbmath.org/authors/?q=ai:malcher.andreasSummary: Iterative arrays whose internal inter-cell communication is quantitatively restricted are investigated. The quantity of communication is measured by counting the number of uses of the links between cells. In particular, iterative arrays are studied where the maximum number of communications per cell occurring in accepting computations is drastically bounded by a constant number. Additionally, the iterative arrays have to work in realtime. We study the computational capacity of such devices. For example, a result is that a strict and dense hierarchy with respect to the constant number of communications exists. Due to their very restricted communication, the question arises whether the usually studied decidability problems such as, for example, emptiness, finiteness, inclusion, or equivalence become decidable for such devices. However, it can be shown that all such decidability questions remain undecidable even if only four communications per cell are allowed. Finally, the undecidability results are shown to hold as well for one-way and two-way cellular automata having at most four communications per cell.Shrinking one-way cellular automatahttps://zbmath.org/1530.681742024-04-15T15:10:58.286558Z"Kutrib, Martin"https://zbmath.org/authors/?q=ai:kutrib.martin"Malcher, Andreas"https://zbmath.org/authors/?q=ai:malcher.andreas"Wendlandt, Matthias"https://zbmath.org/authors/?q=ai:wendlandt.matthiasSummary: We investigate cellular automata as acceptors for formal languages. In particular, we consider real-time one-way cellular automata (OCA) with the additional property that during a computation any cell of the OCA has the ability to dissolve itself, so-called shrinking one-way cellular automata (SOCA). It turns out that real-time SOCA are more powerful than real-time OCA, since they can accept certain linear-time OCA languages. On the other hand, linear-time OCA are more powerful than real-time SOCA, which is witnessed even by a unary language. Additionally, a construction is provided that enables real-time SOCA to accept the reversal of real-time iterative array languages. Finally, restricted real-time SOCA are investigated. We distinguish two limitations for the dissolving of cells. One restriction is to bound the total number of cells that are allowed to dissolve by some function. In this case, an infinite strict hierarchy of language classes is obtained. The second restriction is inspired by an approach to limit the amount of nondeterminism in OCA. Compared with the first restriction, the total number of cells that may dissolve is still unbounded, but the number of time steps at which a cell may dissolve is bounded. The possibility to dissolve is allowed only in the first \(k\) time steps, where \(k\ge 0\) is some constant. For this mode of operation an infinite, tight, and strict hierarchy of language classes is obtained as well.Error detection and correction algorithms for the firing squad synchronization problemhttps://zbmath.org/1530.681752024-04-15T15:10:58.286558Z"Kyritsis, Apostolos"https://zbmath.org/authors/?q=ai:kyritsis.apostolos"Liolis, Orestis"https://zbmath.org/authors/?q=ai:liolis.orestis"Sirakoulis, Georgios Ch."https://zbmath.org/authors/?q=ai:sirakoulis.georgios-chSummary: One of the most famous problems in computer science and cellular automata (CAs) is the Firing Squad Synchronization Problem (FSSP). In the FSSP, a one-dimensional CA with just a single active cell (initially called ``General'') eventually reaches a state in which all the CA cells (called ``soldiers'' in analogy to real-world firing squad) are simultaneously active. Since the introduction of the FSSP as a well known problem in the 60's, and during the last decades, many FSSP solution algorithms have been proposed in the literature. Nevertheless, the inherited error correction capabilities of these algorithms have not been extensively studied. In this paper, an error detection and correction algorithm that utilizes the patterns appearing in 1-D Mazoyer's 8-state solution is analyzed and presented. Furthermore, the patterns of 2-D Umeo's FSSP algorithm are also thoroughly investigated. In such a case, extra patterns emerge from CA cells grouping, during the application of 1-D FSSP solution to 2-D CA grid, enhancing the error tolerance of the proposed algorithm, i.e. almost every possible error can be detected. Finally, another version, even more efficient, of error detection and correction algorithm with memory effect considering previous CA states usage, is also introduced. Although the usage of previous CA states results to increased utilization of computational resources, at the same time it enables the proposed algorithm to detect every possible error state in every possible CA cell, advancing significantly the algorithm's performance.Synthesis of maximum length cellular automata with nonlinearity injectionshttps://zbmath.org/1530.681762024-04-15T15:10:58.286558Z"Maiti, Swapan"https://zbmath.org/authors/?q=ai:maiti.swapan"Roy Chowdhury, Dipanwita"https://zbmath.org/authors/?q=ai:chowdhury.dipanwita-roySummary: Nonlinear functions are essential in different crypto primitives as they play an important role in the security of cryptosystems. In literature, elementary nonlinear Cellular Automata (CA) are exploited in designing cryptosystems, but they have some limitations. Nonlinear CA synthesized from linear elementary CA with nonlinearity injections may be explored as better crypto primitives. In this work, we study maximum length nonlinear hybrid CA (M-NHCA) with single nonlinearity injection, and introduce methods for synthesizing M-NHCA with multiple injections, and explore analytical behavior of these synthetic nonlinear CA. It can be shown that the synthetic nonlinear CA with multiple nonlinearity injections are better crypto primitives.Hierarchies and undecidability results for iterative arrays with sparse communicationhttps://zbmath.org/1530.681772024-04-15T15:10:58.286558Z"Malcher, Andreas"https://zbmath.org/authors/?q=ai:malcher.andreasSummary: Iterative arrays with restricted internal inter-cell communication are investigated. A quantitative measure for the communication is defined by counting the number of uses of the links between cells and it is differentiated between the sum of all communications of an accepting computation and the maximum number of communications per cell occurring in accepting computations. The computational complexity of both classes of devices is investigated and put into relation. In addition, a strict hierarchy depending on the maximum number of communications per cell is established. Furthermore, it is shown that almost all commonly studied decidability questions are not semidecidable for iterative arrays with restricted communication. Finally, non-recursive trade-offs are proved among the iterative arrays providing the strict hierarchy depending on the maximum number of communications per cell.Computing the periods of preimages in surjective cellular automatahttps://zbmath.org/1530.681782024-04-15T15:10:58.286558Z"Mariot, Luca"https://zbmath.org/authors/?q=ai:mariot.luca"Leporati, Alberto"https://zbmath.org/authors/?q=ai:leporati.alberto"Dennunzio, Alberto"https://zbmath.org/authors/?q=ai:dennunzio.alberto"Formenti, Enrico"https://zbmath.org/authors/?q=ai:formenti.enricoSummary: A basic property of one-dimensional surjective cellular automata (CA) is that any preimage of a spatially periodic configuration (SPC) is spatially periodic as well. This paper investigates the relationship between the periods of SPC and the periods of their preimages for various classes of CA. When the CA is only surjective and \(y\) is a SPC of least period \(p\), the least periods of all preimages of \(y\) are multiples of \(p\). By leveraging on the de Bruijn graph representation of CA, we devise a general algorithm to compute the least periods appearing in the preimages of a SPC, along with their corresponding multiplicities (i.e. how many preimages have a particular least period). Next, we consider the case of linear and bipermutive cellular automata (LBCA) defined over a finite field as state alphabet. In particular, we show an equivalence between preimages of LBCA and concatenated linear recurring sequences (LRS) that allows us to give a complete characterization of their periods. Finally, we generalize these results to LBCA defined over a finite ring as alphabet.Search space reduction of asynchrony immune cellular automatahttps://zbmath.org/1530.681792024-04-15T15:10:58.286558Z"Mariot, Luca"https://zbmath.org/authors/?q=ai:mariot.luca"Manzoni, Luca"https://zbmath.org/authors/?q=ai:manzoni.luca-e"Dennunzio, Alberto"https://zbmath.org/authors/?q=ai:dennunzio.albertoSummary: We continue the study of asynchrony immunity in cellular automata (CA), which can be considered as a generalization of correlation immunity in the case of vectorial Boolean functions. The property could have applications as a countermeasure for side-channel attacks in CA-based cryptographic primitives, such as S-boxes and pseudorandom number generators. We first give some theoretical results on the properties that a CA rule must satisfy in order to meet asynchrony immunity, like central permutivity. Next, we perform an exhaustive search of all asynchrony immune CA rules of neighborhood size up to 5, leveraging on the discovered theoretical properties to greatly reduce the size of the search space.Heuristic search of (semi-)bent functions based on cellular automatahttps://zbmath.org/1530.681802024-04-15T15:10:58.286558Z"Mariot, Luca"https://zbmath.org/authors/?q=ai:mariot.luca"Saletta, Martina"https://zbmath.org/authors/?q=ai:saletta.martina"Leporati, Alberto"https://zbmath.org/authors/?q=ai:leporati.alberto"Manzoni, Luca"https://zbmath.org/authors/?q=ai:manzoni.luca-eSummary: An interesting thread in the research of Boolean functions for cryptography and coding theory is the study of \textit{secondary constructions}: given a known function with a good cryptographic profile, the aim is to extend it to a (usually larger) function possessing analogous properties. In this work, we continue the investigation of a secondary construction based on cellular automata (CA), focusing on the classes of bent and semi-bent functions. We prove that our construction preserves the algebraic degree of the local rule, and we narrow our attention to the subclass of quadratic functions, performing several experiments based on exhaustive combinatorial search and heuristic optimization through Evolutionary Strategies (ES). Finally, we classify the obtained results up to permutation equivalence, remarking that the number of equivalence classes that our CA-XOR construction can successfully extend grows very quickly with respect to the CA diameter.Complexity-theoretic aspects of expanding cellular automatahttps://zbmath.org/1530.681812024-04-15T15:10:58.286558Z"Modanese, Augusto"https://zbmath.org/authors/?q=ai:modanese.augustoSummary: The expanding cellular automata (XCA) variant of cellular automata is investigated and characterized from a complexity-theoretical standpoint. An XCA is a one-dimensional cellular automaton which can dynamically create new cells between existing ones. The respective polynomial-time complexity class is shown to coincide with \({\le_\mathrm{tt}^\mathrm{p}}(\textsf{NP})\), that is, the class of decision problems polynomial-time truth-table reducible to problems in \(\textsf{NP} \). An alternative characterization based on a variant of non-deterministic Turing machines is also given. In addition, corollaries on select XCA variants are proven: XCAs with multiple accept and reject states are shown to be polynomial-time equivalent to the original XCA model. Finally, XCAs with alternative acceptance conditions are considered and classified in terms of \({\le_\mathrm{tt}^\mathrm{p}}(\textsf{NP})\) and the Turing machine polynomial-time class \(\textsf{P} \).Correction to: ``Complexity-theoretic aspects of expanding cellular automata''https://zbmath.org/1530.681822024-04-15T15:10:58.286558Z"Modanese, Augusto"https://zbmath.org/authors/?q=ai:modanese.augustoFrom the text: In the original publication [ibid. 21, No. 1, 53--65 (2022; Zbl 1530.68181)], certain mathematical formulas were rendered incorrectly or are missing from the text.
The original article has been corrected.A universal non-conservative reversible elementary triangular partitioned cellular automaton that shows complex behaviorhttps://zbmath.org/1530.681832024-04-15T15:10:58.286558Z"Morita, Kenichi"https://zbmath.org/authors/?q=ai:morita.kenichiSummary: We study a simple triangular partitioned cellular automaton (TPCA), and clarify its complex behavior. It is a CA with triangular cells, each of which is divided into three parts. The next state of a cell is determined by the three adjacent parts of its neighbor cells. This framework makes it easy to design reversible triangular CAs. Among them, isotropic and eight-state (i.e., each part has only two states) TPCAs are called \textit{elementary TPCAs} (ETPCAs). They are extremely simple, since each of their local transition functions is described by only four local rules. In this paper, we investigate a specific reversible ETPCA \(T_{0347} \), where 0347 is its identification number in the class of 256 ETPCAs. In spite of the simplicity of the local function and the constraint of reversibility, evolutions of configurations in \(T_{0347}\) have very rich varieties. It is shown that a glider, which is a space-moving pattern, and glider guns exist in this cellular space We also show that the trajectory and the timing of a glider can be fully controlled by appropriately placing stable patterns called blocks. Furthermore, using gliders to represent signals, we can implement universal reversible logic gates in it. By this, computational universality of \(T_{0347}\) is derived.Reversible cellular automata: a natural clustering techniquehttps://zbmath.org/1530.681842024-04-15T15:10:58.286558Z"Mukherjee, Sukanya"https://zbmath.org/authors/?q=ai:mukherjee.sukanya"Bhattacharjee, Kamalika"https://zbmath.org/authors/?q=ai:bhattacharjee.kamalika"Das, Sukanta"https://zbmath.org/authors/?q=ai:das.sukantaSummary: This work proposes reversible finite cellular automaton (CA) as a natural clustering tool, where closeness between two configurations is measured as whether they are reachable from each other. As any finite reversible CA distributes its configurations into a number of cyclic spaces, so, two configurations belonging to the same cycle are close to each other. Exploiting this behavior, we treat reversible CA as a natural clustering technique where each of the cyclic spaces forms a unique cluster. To use this characteristics, real data objects are mapped to binary strings (configurations of a CA) using a surjective encoding function. Some properties are identified to filter candidate cellular automata (CAs) that perform effective clustering. Further, an iterative algorithm is also proposed that guarantees that only the desired number of clusters are formed. Finally, performance of our algorithm on real data is measured using some standard validation indices. While comparing with the existing benchmark clustering algorithms, we have observed that our algorithm is at least at par with the best algorithms existing today. So, if chosen appropriately, the locality and interconnectivity of simple systems like reversible CAs have the potential to do the best clustering of any real-life data-set.The Ameyalli-rule: logical universality in a 2D cellular automatonhttps://zbmath.org/1530.681852024-04-15T15:10:58.286558Z"Soto, José Manuel Gómez"https://zbmath.org/authors/?q=ai:gomez-soto.jose-manuel"Wuensche, Andrew"https://zbmath.org/authors/?q=ai:wuensche.andrewSummary: We present a new spontaneously emergent glider-gun in a 2D Cellular Automaton and build the logical gates NOT, AND and OR required for logical universality. The Ameyalli-rule is not based on survival/birth logic but depends on 102 isotropic neighborhood groups making an iso-rule, which can drive an interactive input-frequency histogram for visualising iso-group activity and dependent functions for filtering and mutation. Neutral inputs relative to logical gates are identified which provide an idealized striped-down form of the iso-rule.State-efficient realization of fault-tolerant FSSP algorithmshttps://zbmath.org/1530.681862024-04-15T15:10:58.286558Z"Umeo, Hiroshi"https://zbmath.org/authors/?q=ai:umeo.hiroshi"Kamikawa, Naoki"https://zbmath.org/authors/?q=ai:kamikawa.naoki"Maeda, Masashi"https://zbmath.org/authors/?q=ai:maeda.masashi"Fujita, Gen"https://zbmath.org/authors/?q=ai:fujita.genSummary: The firing squad synchronization problem (FSSP, for short) on cellular automata has been studied extensively for more than fifty years, and a rich variety of FSSP algorithms has been proposed. Here we study the classical FSSP on a model of fault-tolerant cellular automata that might have possibly some defective cells and present the first state-efficient implementations of fault-tolerant FSSP algorithms for one-dimensional (1D) and two-dimensional (2D) cellular arrays. It is shown that, under some constraints on the length and distribution of defective cells, any 1D cellular array of length \(n\) with \(p\) defective cell segments can be synchronized in \(2n-2+p\) steps and the algorithm is realized on a 1D cellular automaton of length \(n, 2 \le n \le 50\), having 164 states and 4792 transition rules. In addition, we give by far a smaller-state implementation of a 2D FSSP algorithm that can synchronize any 2D rectangular array of size \(m \times n\), possibly including at most \(O(mn)\) isolated defective zones, exactly in \(2(m+n)-4\) steps on a cellular automaton with only 6 states and 935 transition rules.A lower bound on complexity of a locator cellular automaton solution for the closest neighbor search problemhttps://zbmath.org/1530.681872024-04-15T15:10:58.286558Z"Vasilev, D. I."https://zbmath.org/authors/?q=ai:vasilev.d-i"Gasanov, E. E."https://zbmath.org/authors/?q=ai:gasanov.elyar-eSummary: The paper considers the application of the locator cellular automaton model to the closest neighbor search problem. The locator cellular automaton model assumes the possibility for each cell to translate a signal through any distance using the ether. It was proven earlier that the ether model allows solving the problem with logarithmic time. In this paper we have derived a logarithmic lower bound for this problem.Algorithmic information dynamics of cellular automatahttps://zbmath.org/1530.681882024-04-15T15:10:58.286558Z"Zenil, Hector"https://zbmath.org/authors/?q=ai:zenil.hector"Adams, Alyssa"https://zbmath.org/authors/?q=ai:adams.alyssa-mSummary: We illustrate an application of Algorithmic Information Dynamics (AID) to Cellular Automata (CA) demonstrating how this digital calculus is able to quantify change in discrete dynamical systems. We demonstrate the sensitivity of the Block Decomposition Method on 1D and 2D CA, including Conway's Game of Life, against measures of statistical nature such as compression (such as Lempel-Ziv-Welch) and Shannon Entropy in two different contexts (1) perturbation analysis and (2) dynamic-state colliding CA. The approach is interesting because it analyses a quintessential object native to software space (CA) in software space itself by using algorithmic information dynamics through a model-driven universal search instead of a traditional statistical approach e.g. LZW compression or Shannon entropy. The colliding example of two state-independent (if not three as one is regulating the collision itself) discrete dynamical systems offers a potential proof of concept for the development of a multivariate version of the AID calculus.
For the entire collection see [Zbl 1491.11006].Avoid one's doom: finding cliff-edge configurations in Petri netshttps://zbmath.org/1530.681892024-04-15T15:10:58.286558Z"Aguirre-Samboní, Giann Karlo"https://zbmath.org/authors/?q=ai:aguirre-samboni.giann-karlo"Haar, Stefan"https://zbmath.org/authors/?q=ai:haar.stefan"Paulevé, Loïc"https://zbmath.org/authors/?q=ai:pauleve.loic"Schwoon, Stefan"https://zbmath.org/authors/?q=ai:schwoon.stefan"Würdemann, Nick"https://zbmath.org/authors/?q=ai:wurdemann.nickSummary: A crucial question in analyzing a concurrent system is to determine its long-run behaviour, and in particular, whether there are irreversible choices in its evolution, leading into parts of the reachability space from which there is no return to other parts. Casting this problem in the unifying framework of safe Petri nets, our previous work has provided techniques for identifying \textit{attractors}, i.e. terminal strongly connected components of the reachability space, whose attraction basins we wish to determine. Here, we provide a solution for the case of safe Petri nets. Our algorithm uses net unfoldings and provides a map of all of the system's configurations (concurrent executions) that act as \textit{cliff-edges}, i.e. any maximal extension for those configurations lies in some basin that is considered fatal. The computation turns out to require only a relatively small prefix of the unfolding, just twice the depth of Esparza's complete prefix.
For the entire collection see [Zbl 1522.68028].Concurrency in Boolean networkshttps://zbmath.org/1530.681902024-04-15T15:10:58.286558Z"Chatain, Thomas"https://zbmath.org/authors/?q=ai:chatain.thomas"Haar, Stefan"https://zbmath.org/authors/?q=ai:haar.stefan"Kolčák, Juraj"https://zbmath.org/authors/?q=ai:kolcak.juraj"Paulevé, Loïc"https://zbmath.org/authors/?q=ai:pauleve.loic"Thakkar, Aalok"https://zbmath.org/authors/?q=ai:thakkar.aalokSummary: Boolean networks (BNs) are widely used to model the qualitative dynamics of biological systems. Besides the logical rules determining the evolution of each component with respect to the state of its regulators, the scheduling of component updates can have a dramatic impact on the predicted behaviours. In this paper, we explore the use of Read (contextual) Petri Nets (RPNs) to study dynamics of BNs from a concurrency theory perspective. After showing bi-directional translations between RPNs and BNs and analogies between results on synchronism sensitivity, we illustrate that usual updating modes for BNs can miss plausible behaviours, i.e., incorrectly conclude on the absence/impossibility of reaching specific configurations. We propose an encoding of BNs capitalizing on the RPN semantics enabling more behaviour than the generalized asynchronous updating mode. The proposed encoding ensures a correct abstraction of any multivalued refinement, as one may expect to achieve when modelling biological systems with no assumption on its time features.Realizable and context-free hyperlanguageshttps://zbmath.org/1530.681912024-04-15T15:10:58.286558Z"Frenkel, Hadar"https://zbmath.org/authors/?q=ai:frenkel.hadar"Sheinvald, Sarai"https://zbmath.org/authors/?q=ai:sheinvald.saraiSummary: Hyperproperties lift conventional trace-based languages from a set of execution traces to a set of sets of executions. From a formal-language perspective, these are sets of sets of words, namely \textit{hyperlanguages}. \textit{Hyperautomata} are based on classical automata models that are lifted to handle hyperlanguages. \textit{Finite hyperautomata} (NFH) have been suggested to express regular hyperproperties. We study the \textit{realizability} problem for regular hyperlanguages: given a set of languages, can it be precisely described by an NFH? We show that the problem is complex already for singleton hyperlanguages. We then go beyond regular hyperlanguages, and study \textit{context-free} hyperlanguages. We show that the natural extension to context-free hypergrammars is highly undecidable. We then suggest a refined model, namely \textit{synchronous hypergrammars}, which enables describing interesting non-regular hyperproperties, while retaining many decidable properties of context-free grammars.
For the entire collection see [Zbl 1522.68028].A categorical semantics for bounded Petri netshttps://zbmath.org/1530.681922024-04-15T15:10:58.286558Z"Genovese, Fabrizio Romano"https://zbmath.org/authors/?q=ai:genovese.fabrizio-romano"Loregian, Fosco"https://zbmath.org/authors/?q=ai:loregian.fosco"Palombi, Daniele"https://zbmath.org/authors/?q=ai:palombi.danieleSummary: We provide a categorical semantics for bounded Petri nets, both in the collective- and individual-token philosophy. In both cases, we describe the process of bounding a net internally, by just constructing new categories of executions of a net using comonads, and externally, using lax-monoidal-lax functors. Our external semantics is non-local, meaning that tokens are endowed with properties that say something about the global state of the net. We then prove, in both cases, that the internal and external constructions are equivalent, by using machinery built on top of the Grothendieck construction. The individual-token case is harder, as it requires a more explicit reliance on abstract methods.
For the entire collection see [Zbl 1522.68034].Comparing channel restrictions of communicating state machines, high-level message sequence charts, and multiparty session typeshttps://zbmath.org/1530.681932024-04-15T15:10:58.286558Z"Stutz, Felix"https://zbmath.org/authors/?q=ai:stutz.felix"Zufferey, Damien"https://zbmath.org/authors/?q=ai:zufferey.damienSummary: Communicating state machines provide a formal foundation for distributed computation. Unfortunately, they are Turing-complete and, thus, challenging to analyse. In this paper, we classify restrictions on channels which have been proposed to work around the undecidability of verification questions. We compare half-duplex communication, existential \(B\)-boundedness, and \(k\)-synchronisability. These restrictions do not prevent the communication channels from growing arbitrarily large but still restrict the power of the model. Each restriction gives rise to a set of languages so, for every pair of restrictions, we check whether one subsumes the other or if they are incomparable. We investigate their relationship in two different contexts: first, the one of communicating state machines, and, second, the one of communication protocol specifications using high-level message sequence charts. Surprisingly, these two contexts yield different conclusions. In addition, we integrate multiparty session types, another approach to specify communication protocols, into our classification. We show that multiparty session type languages are half-duplex, existentially 1-bounded, and 1-synchronisable. To show this result, we provide the first formal embedding of multiparty session types into high-level message sequence charts.
For the entire collection see [Zbl 1522.68028].Reachability problems for transmission graphshttps://zbmath.org/1530.681942024-04-15T15:10:58.286558Z"An, Shinwoo"https://zbmath.org/authors/?q=ai:an.shinwoo"Oh, Eunjin"https://zbmath.org/authors/?q=ai:oh.eunjinSummary: Let \(P\) be a set of \(n\) points in the plane where each point \(p\) of \(P\) is associated with a radius \(r_p>0\). The transmission graph \(G=(P,E)\) of \(P\) is defined as the directed graph such that \(E\) contains an edge from \(p\) to \(q\) if and only if \(|pq|\le r_p\) for any two points \(p\) and \(q\) in \(P\), where \(|pq|\) denotes the Euclidean distance between \(p\) and \(q\). In this paper, we present a data structure of size \(O(n^{5/3})\) such that for any two points in \(P\), we can check in \(O(n^{2/3})\) time if there is a path in \(G\) between the two points. This is the first data structure for answering reachability queries whose performance depends only on \(n\) but not on the radius ratio.
For the entire collection see [Zbl 1482.68032].Reachability problems for transmission graphshttps://zbmath.org/1530.681952024-04-15T15:10:58.286558Z"An, Shinwoo"https://zbmath.org/authors/?q=ai:an.shinwoo"Oh, Eunjin"https://zbmath.org/authors/?q=ai:oh.eunjinSummary: Let \(P\) be a set of \(n\) points in the plane where each point \(p\) of \(P\) is associated with a radius \(r_p>0\). The transmission graph \(G=(P,E)\) of \(P\) is defined as the directed graph such that \(E\) contains an edge from \(p\) to \(q\) if and only if \(|pq|\le r_p\) for any two points \(p\) and \(q\) in \(P\), where \(|pq|\) denotes the Euclidean distance between \(p\) and \(q\). In this paper, we present a data structure of size \(O(n^{5/3})\) such that for any two points in \(P\), we can check in \(O(n^{2/3})\) time if there is a path in \(G\) between the two points. This is the first data structure for answering reachability queries whose performance depends only on \(n\) but not on the ratio between the largest and smallest radii.Distributed exact weighted all-pairs shortest paths in randomized near-linear timehttps://zbmath.org/1530.681962024-04-15T15:10:58.286558Z"Bernstein, Aaron"https://zbmath.org/authors/?q=ai:bernstein.aaron"Nanongkai, Danupon"https://zbmath.org/authors/?q=ai:nanongkai.danuponSummary: In the \textit{distributed all-pairs shortest paths} problem, every node in the weighted undirected distributed network (the CONGEST model) needs to know the distance from every other node using least number of communication rounds (typically called \textit{time complexity}). The problem admits a \((1+o(1))\)-approximation \(\tilde\Theta(n)\)-time algorithm and a nearly tight \(\tilde \Omega(n)\) lower bound
[\textit{D. Nanongkai}, STOC 2014, 565--573 (2014; Zbl 1315.05136);
\textit{C. Lenzen} and \textit{B. Patt-Shamir}, PODC '15, 153--162 (2015; Zbl 1333.68280)].
(\( \tilde \Theta\), \(\tilde O\) and \(\tilde \Omega\) hide polylogarithmic factors.) Note that the lower bounds also hold even in the unweighted case and in the weighted case with polynomial approximation ratios
[\textit{C. Lenzen} and \textit{D. Peleg}, PODC '13, 375--382 (2013; Zbl 1323.68421);
\textit{S. Holzer} and \textit{R. Wattenhofer}, PODC '12, 355--364 (2012; Zbl 1301.68256);
\textit{D. Peleg} et al., Lect. Notes Comput. Sci. 7392, 660--672 (2012; Zbl 1343.68283);
\textit{D. Nanongkai}, STOC 2014, 565--573 (2014; Zbl 1315.05136)].
For the exact case,
\textit{M. Elkin} [STOC 2017, 757--770 (2017; Zbl 1369.68344)]
presented an \(O(n^{5/3} \log^{2/3} n)\) time bound, which was later improved to \(\tilde O(n^{5/4})\)
[\textit{C.-C. Huang} et al., FOCS 2017, 168--179 (2017; \url{doi:10.1109/FOCS.2017.24})].
It was shown that any superlinear lower bound (in \(n)\) requires a new technique
[\textit{K. Censor-Hillel} et al., LIPIcs -- Leibniz Int. Proc. Inform. 91, Article 10, 16 p. (2017; Zbl 1515.68230)], but otherwise it remained widely open whether there exists a \(\tilde O(n)\)-time algorithm for the exact case, which would match the best possible approximation algorithm.
This paper resolves this question positively: we present a randomized (Las Vegas) \( \tilde O(n)\)-time algorithm, matching the lower bound up to polylogarithmic factors. Like the previous \(\tilde O(n^{5/4})\) bound, our result works for directed graphs with zero (and even negative) edge weights. In addition to the improved running time, our algorithm works in a more general setting than that required by the previous \(\tilde O(n^{5/4})\) bound; in our setting (i) the communication is only along edge directions (as opposed to bidirectional), and (ii) edge weights are arbitrary (as opposed to integers in \(\{1, 2,\dots,\operatorname{poly}(n)\} )\). As far as we know, ours is the first \(o(n^2)\) algorithm that only requires unidirectional communication. For arbitrary weights, the previous state-of-the-art required \(\tilde O(n^{4/3})\) time
[\textit{U. Agarwal} and \textit{V. Ramachandran}, IPDPS 2019, 23--32 (2019; \url{doi: 10.1109/IPDPS.2019.00014});
SPAA '20, 11--21 (2020; \url{doi:10.1145/3350755.3400256})].
Our algorithm is extremely simple and relies on a new technique called \textit{random filtered broadcast}. Given any sets of nodes \(A,B\subseteq V\) and assuming that every \(b \in B\) knows all distances from nodes in \(A\), and every node \(v \in V\) knows all distances from nodes in \(B\), we want every \(v\in V\) to know \(\mathsf{DistThrough}_B(a,v)=\min_{b\in B}\mathsf{dist}(a,b)+\mathsf{dist}(b,v)\) for every \(a\in A\). Previous works typically solve this problem by broadcasting all knowledge of every \(b\in B\), causing superlinear edge congestion and time. We show a randomized algorithm that can reduce edge congestions and thus solve this problem in \(\tilde O(n)\) expected time.Spectral rank monotonicity on undirected networkshttps://zbmath.org/1530.681972024-04-15T15:10:58.286558Z"Boldi, Paolo"https://zbmath.org/authors/?q=ai:boldi.paolo"Furia, Flavio"https://zbmath.org/authors/?q=ai:furia.flavio"Vigna, Sebastiano"https://zbmath.org/authors/?q=ai:vigna.sebastianoSummary: We study the problem of \textit{score} and \textit{rank} monotonicity for \textit{spectral ranking} methods, such as eigenvector centrality and PageRank, in the case of undirected networks. Score monotonicity means that adding an edge increases the score at both ends of the edge. Rank monotonicity means that adding an edge improves the relative position of both ends of the edge with respect to the remaining nodes. It is known that common spectral rankings are both score and rank monotone on directed, strongly connected graphs. We show that, surprisingly, the situation is very different for undirected graphs, and in particular that PageRank is neither score nor rank monotone.
For the entire collection see [Zbl 1492.94005].The complexity of \((\Delta+1)\) coloring in congested clique, massively parallel computation, and centralized local computationhttps://zbmath.org/1530.681982024-04-15T15:10:58.286558Z"Chang, Yi-Jun"https://zbmath.org/authors/?q=ai:chang.yi-jun"Fischer, Manuela"https://zbmath.org/authors/?q=ai:fischer.manuela"Ghaffari, Mohsen"https://zbmath.org/authors/?q=ai:ghaffari.mohsen"Uitto, Jara"https://zbmath.org/authors/?q=ai:uitto.jara"Zheng, Yufan"https://zbmath.org/authors/?q=ai:zheng.yufanA simple extension of the bag-of-paths model weighting path lengths by a Poisson distributionhttps://zbmath.org/1530.681992024-04-15T15:10:58.286558Z"Courtain, Sylvain"https://zbmath.org/authors/?q=ai:courtain.sylvain"Saerens, Marco"https://zbmath.org/authors/?q=ai:saerens.marcoSummary: This work extends the bag-of-paths model [\textit{K. Françoisse} et al., Neural Netw. 90, 90--111 (2017; Zbl 1434.68535)] by introducing a weighting of the length of the paths in the network, provided by a Poisson probability distribution. The main advantage of this approach is that it allows to tune the mean path length parameter which is most relevant for the application at hand. Various quantities of interest, such as the probability of drawing a path from the bag of paths, or the join probability of sampling any path connecting two nodes of interest, can easily be computed in closed form from this model. In this context, a new distance measure between nodes of a network, considering a weighting factor on the length of the paths, is defined. Experiments on semi-supervised classification tasks show that the introduced distance measure provides competitive results compared to other state-of-the-art methods. Moreover, a new interpretation of the logarithmic communicability similarity measure [\textit{V. Ivashkin} and \textit{P. Chebotarev}, Springer Proc. Math. Stat. 197, 87--105 (2017; Zbl 1380.05186)] is proposed in terms of the new model.
For the entire collection see [Zbl 1492.94005].Graph spanners in the message-passing modelhttps://zbmath.org/1530.682002024-04-15T15:10:58.286558Z"Fernández V., Manuel"https://zbmath.org/authors/?q=ai:fernandez-v.manuel"Woodruff, David P."https://zbmath.org/authors/?q=ai:woodruff.david-p"Yasuda, Taisuke"https://zbmath.org/authors/?q=ai:yasuda.taisukeSummary: Graph spanners are sparse subgraphs which approximately preserve all pairwise shortest-path distances in an input graph. The notion of approximation can be additive, multiplicative, or both, and many variants of this problem have been extensively studied. We study the problem of computing a graph spanner when the edges of the input graph are distributed across two or more sites in an arbitrary, possibly worst-case partition, and the goal is for the sites to minimize the communication used to output a spanner. We assume the message-passing model of communication, for which there is a point-to-point link between all pairs of sites as well as a coordinator who is responsible for producing the output. We stress that the subset of edges that each site has is not related to the network topology, which is fixed to be point-to-point. While this model has been extensively studied for related problems such as graph connectivity, it has not been systematically studied for graph spanners. We present the first tradeoffs for total communication versus the quality of the spanners computed, for two or more sites, as well as for additive and multiplicative notions of distortion. We show separations in the communication complexity when edges are allowed to occur on multiple sites, versus when each edge occurs on at most one site. We obtain nearly tight bounds (up to polylog factors) for the communication of additive 2-spanners in both the with and without duplication models, multiplicative \((2k-1)\)-spanners in the with duplication model, and multiplicative 3 and 5-spanners in the without duplication model. Our lower bound for multiplicative 3-spanners employs biregular bipartite graphs rather than the usual Erdős girth conjecture graphs and may be of wider interest.
For the entire collection see [Zbl 1434.68035].Counting homomorphisms to \(K_4\)-minor-free graphs, modulo 2https://zbmath.org/1530.682012024-04-15T15:10:58.286558Z"Focke, Jacob"https://zbmath.org/authors/?q=ai:focke.jacob"Goldberg, Leslie Ann"https://zbmath.org/authors/?q=ai:goldberg.leslie-ann"Roth, Marc"https://zbmath.org/authors/?q=ai:roth.marc"Živný, Stanislav"https://zbmath.org/authors/?q=ai:zivny.stanislavSummary: We study the problem of computing the parity of the number of homomorphisms from an input graph \(G\) to a fixed graph \(H\). \textit{J. Faben} and \textit{M. Jerrum} [Theory Comput. 11, Paper No. 2, 35--57 (2015; Zbl 1336.68122)] introduced an explicit criterion on the graph \(H\) and conjectured that, if satisfied, the problem is solvable in polynomial time and, otherwise, the problem is complete for the complexity class \(\oplus\mathrm{P}\) of parity problems. We verify their conjecture for all graphs \(H\) that exclude the complete graph on four vertices as a minor. Further, we rule out the existence of a subexponential-time algorithm for the \(\oplus\mathrm{P}\)-complete cases, assuming the randomized exponential time hypothesis. Our proofs introduce a novel method of deriving hardness from globally defined substructures of the fixed graph \(H\). Using this, we subsume all prior progress toward resolving the conjecture [\textit{J. Faben} and \textit{M. Jerrum}, Theory Comput. 11, Paper No. 2, 35--57 (2015; Zbl 1336.68122); \textit{A. Göbel} et al., ACM Trans. Comput. Theory 6, No. 4, Article No. 17, 29 p. (2014; Zbl 1347.68181); ACM Trans. Comput. Theory 8, No. 3, Article No. 12, 29 p. (2016; Zbl 1427.68241)]. As special cases, our machinery also yields a proof of the conjecture for graphs with maximum degree at most 3, as well as a full classification for the problem of counting list homomorphisms, modulo 2.Subgraph matching on temporal graphshttps://zbmath.org/1530.682022024-04-15T15:10:58.286558Z"Li, Faming"https://zbmath.org/authors/?q=ai:li.faming"Zou, Zhaonian"https://zbmath.org/authors/?q=ai:zou.zhaonianSummary: Temporal graphs are graphs whose edges are associated with timestamps. Subgraph matching on temporal graphs retrieves temporal subgraphs whose edge timestamps satisfy user-specified temporal orders. In this paper, a temporal query pattern is composed of a query graph with an arbitrary structure and a partial order on the edge set of the query graph. Moreover, the time span between the minimum and the maximum edge timestamps in a matching is required to be less than or equal to a specified threshold. This paper proposes a temporal subgraph matching algorithm based on two key techniques. First, a memory-efficient index structure called TO-tree is designed to compactly store all necessary information required for finding all temporal subgraph matchings. The TO-tree constructed for a temporal query pattern is much smaller than the temporal graph because unnecessary information is mostly excluded from the TO-tree by three powerful filters. The second technique is a temporal subgraph matching enumeration method that runs on the TO-tree instead of on the temporal graph. This enumeration method expands temporal subgraph matchings in an edge-by-edge manner. Since the TO-tree can fit into the main memory, the enumeration method runs very fast on the TO-tree. An extensive experimental evaluation has been carried out. The experimental results show that the TO-tree index structure is memory-efficient, which in turn enables a fast temporal subgraph matching enumeration. Overall, our algorithm is at least 3X faster than the baseline algorithm adapted from the state-of-the-art non-temporal subgraph matching algorithm \textsf{CECI} and is at least 4X faster than the temporal subgraph matching algorithm \textsf{HASSE}.New clusterization method based on graph connectivity searchhttps://zbmath.org/1530.682032024-04-15T15:10:58.286558Z"Sadovsky, Michael G."https://zbmath.org/authors/?q=ai:sadovsky.michael-g"Bushmelev, Eugene Yu."https://zbmath.org/authors/?q=ai:bushmelev.eugene-yu"Ostylovsky, Anatoly N."https://zbmath.org/authors/?q=ai:ostylovsky.anatoly-nSummary: New method is proposed to identify clusters in datasets. The method is based on a sequential elimination of the longest distances in dataset, so that the relevant graph looses some edges. The method stops when the graph becomes disconnected.Wiener-type indices of Parikh word representable graphshttps://zbmath.org/1530.682042024-04-15T15:10:58.286558Z"Thomas, Nobin"https://zbmath.org/authors/?q=ai:thomas.nobin"Mathew, Lisa"https://zbmath.org/authors/?q=ai:mathew.lisa"Sriram, Sastha"https://zbmath.org/authors/?q=ai:sriram.sastha"Subramanian, K. G."https://zbmath.org/authors/?q=ai:subramanian.kumbakonam-govindarajanSummary: A new class of graphs \(G(w)\), called Parikh word representable graphs (\textit{PWRG}), corresponding to words \(w\) that are finite sequence of symbols, was considered in the recent past. Several properties of these graphs have been established. In this paper, we consider these graphs corresponding to binary core words of the form \(aub\) over a binary alphabet \(\{a, b\}\). We derive formulas for computing the Wiener index of the \textit{PWRG} of a binary core word. Sharp bounds are established on the value of this index in terms of different parameters related to binary words over \(\{a, b\}\) and the corresponding \textit{PWRGs}. Certain other Wiener-type indices that are variants of Wiener index are also considered. Formulas for computing these indices in the case of \textit{PWRG} of a binary core word are obtained.Optimal low-degree hardness of maximum independent sethttps://zbmath.org/1530.682052024-04-15T15:10:58.286558Z"Wein, Alexander S."https://zbmath.org/authors/?q=ai:wein.alexander-sSummary: We study the algorithmic task of finding a large independent set in a sparse Erdős-Rényi random graph with \(n\) vertices and average degree \(d\). The maximum independent set is known to have size \((2 \log d/d)n\) in the double limit \(n \to \infty\) followed by \(d \to \infty\), but the best known polynomial-time algorithms can only find an independent set of half-optimal size \((\log d/d)n\). We show that the class of \textit{low-degree polynomial algorithms} can find independent sets of half-optimal size but no larger, improving upon a result of Gamarnik, Jagannath, and the author. This generalizes earlier work by Rahman and Virág, which proved the analogous result for the weaker class of \textit{local algorithms}.Semi-supervised learning for aggregated multilayer graphs using diffuse interface methods and fast matrix-vector productshttps://zbmath.org/1530.682062024-04-15T15:10:58.286558Z"Bergermann, Kai"https://zbmath.org/authors/?q=ai:bergermann.kai"Stoll, Martin"https://zbmath.org/authors/?q=ai:stoll.martin"Volkmer, Toni"https://zbmath.org/authors/?q=ai:volkmer.toniSummary: We generalize a graph-based multiclass semi-supervised classification technique based on diffuse interface methods to multilayer graphs. Besides the treatment of various applications with an inherent multilayer structure, we present a very flexible approach that interprets high-dimensional data in a low-dimensional multilayer graph representation. Highly efficient numerical methods involving the spectral decomposition of the corresponding differential graph operators as well as fast matrix-vector products based on the nonequispaced fast Fourier transform enable the rapid treatment of large and high-dimensional data sets. We perform various numerical tests putting a special focus on image segmentation. In particular, we test the performance of our method on data sets with up to 10 million nodes per layer as well as up to 104 dimensions, resulting in graphs with up to 52 layers. While all presented numerical experiments can be run on an average laptop computer, the linear dependence per iteration step of the runtime on the network size in all stages of our algorithm makes it scalable to even larger and higher-dimensional problems.Artificial neural networkshttps://zbmath.org/1530.682072024-04-15T15:10:58.286558Z"Boreland, Bryson"https://zbmath.org/authors/?q=ai:boreland.bryson"Kunze, Herb"https://zbmath.org/authors/?q=ai:kunze.herb-e"Levere, Kimberly M."https://zbmath.org/authors/?q=ai:levere.kimberly-mSummary: Artificial neural networks (ANNs) were designed based on the present understanding of their biological counterpart. An ANN is a system which serves as a fully parallel analog computer to mimic some aspect of cognition. Throughout the mid-2000s, many different architectures have been explored and have won contests related to machine learning and image recognition. This chapter discusses the architecture of the following types of neural networks: the perceptron model, feedforward neural networks, convolutional neural networks (CNNs), recurrent neural networks, and complex-valued neural networks. ANNs have been widely used in recent years, with applications such as image classification, speech recognition, and natural language processing. An ANN is a collection of artificial neurons constructed by connecting neurons with a weighted connection. CNNs are similar to the feedforward ANNs but are typically used to solve image and computer vision-related problems but have also been applied to natural language processing.
For the entire collection see [Zbl 1523.68010].Training very large scale nonlinear SVMs using alternating direction method of multipliers coupled with the hierarchically semi-separable kernel approximationshttps://zbmath.org/1530.682082024-04-15T15:10:58.286558Z"Cipolla, S."https://zbmath.org/authors/?q=ai:cipolla.stefano"Gondzio, J."https://zbmath.org/authors/?q=ai:gondzio.jacekSummary: Typically, nonlinear Support Vector Machines (SVMs) produce significantly higher classification quality when compared to linear ones but, at the same time, their computational complexity is prohibitive for large-scale datasets: this drawback is essentially related to the necessity to store and manipulate large, dense and unstructured kernel matrices. Despite the fact that at the core of training an SVM there is a \textit{simple} convex optimization problem, the presence of kernel matrices is responsible for dramatic performance reduction, making SVMs unworkably slow for large problems. Aiming at an efficient solution of large-scale nonlinear SVM problems, we propose the use of the \textit{Alternating Direction Method of Multipliers} coupled with \textit{Hierarchically Semi-Separable} (HSS) kernel approximations. As shown in this work, the detailed analysis of the interaction among their algorithmic components unveils a particularly efficient framework and indeed, the presented experimental results demonstrate, in the case of Radial Basis Kernels, a significant speed-up when compared to the \textit{state-of-the-art} nonlinear SVM libraries (without significantly affecting the classification accuracy).Reconstructing trees from traceshttps://zbmath.org/1530.682092024-04-15T15:10:58.286558Z"Davies, Sami"https://zbmath.org/authors/?q=ai:davies.sami"Rácz, Miklós Z."https://zbmath.org/authors/?q=ai:racz.miklos-z"Rashtchian, Cyrus"https://zbmath.org/authors/?q=ai:rashtchian.cyrusSummary: We study the problem of learning a node-labeled tree given independent traces from an appropriately defined deletion channel. This problem, tree trace reconstruction, generalizes string trace reconstruction, which corresponds to the tree being a path. For many classes of trees, including complete trees and spiders, we provide algorithms that reconstruct the labels using only a polynomial number of traces. This exhibits a stark contrast to known results on string trace reconstruction, which require exponentially many traces, and where a central open problem is to determine whether a polynomial number of traces suffice. Our techniques combine novel combinatorial and complex analytic methods.Generating random weights and biases in feedforward neural networks with random hidden nodeshttps://zbmath.org/1530.682102024-04-15T15:10:58.286558Z"Dudek, Grzegorz"https://zbmath.org/authors/?q=ai:dudek.grzegorzSummary: Neural networks with random hidden nodes have gained increasing interest from researchers and practical applications. This is due to their unique features such as very fast training and universal approximation property. In these networks the weights and biases of hidden nodes determining the nonlinear feature mapping are set randomly and are not learned. Appropriate selection of the intervals from which weights and biases are selected is extremely important. This topic has not yet been sufficiently explored in the literature. In this work a method of generating random weights and biases is proposed. This method generates the parameters of the hidden nodes in such a way that nonlinear fragments of the activation functions are located in the input space regions with data and can be used to construct the surface approximating a nonlinear target function. The weights and biases are dependent on the input data range and activation function type. The proposed methods allows us to control the generalization degree of the model. These all lead to improvement in approximation performance of the network. Several experiments show very promising results.Are LSTMs good few-shot learners?https://zbmath.org/1530.682112024-04-15T15:10:58.286558Z"Huisman, Mike"https://zbmath.org/authors/?q=ai:huisman.mike"Moerland, Thomas M."https://zbmath.org/authors/?q=ai:moerland.thomas-m"Plaat, Aske"https://zbmath.org/authors/?q=ai:plaat.aske"van Rijn, Jan N."https://zbmath.org/authors/?q=ai:van-rijn.jan-nSummary: Deep learning requires large amounts of data to learn new tasks well, limiting its applicability to domains where such data is available. Meta-learning overcomes this limitation by learning how to learn. \textit{S. Hochreiter} et al. [Lect. Notes Comput. Sci. 2130, 87--94 (2001; Zbl 1001.68724)] showed that an LSTM trained with backpropagation across different tasks is capable of meta-learning. Despite promising results of this approach on small problems, and more recently, also on reinforcement learning problems, the approach has received little attention in the supervised few-shot learning setting. We revisit this approach and test it on modern few-shot learning benchmarks. We find that LSTM, surprisingly, outperform the popular meta-learning technique MAML on a simple few-shot sine wave regression benchmark, but that LSTM, expectedly, fall short on more complex few-shot image classification benchmarks. We identify two potential causes and propose a new method called \textit{Outer Product LSTM (OP-LSTM)} that resolves these issues and displays substantial performance gains over the plain LSTM. Compared to popular meta-learning baselines, OP-LSTM yields competitive performance on within-domain few-shot image classification, and performs better in cross-domain settings by 0.5--1.9\% in accuracy score. While these results alone do not set a new state-of-the-art, the advances of OP-LSTM are orthogonal to other advances in the field of meta-learning, yield new insights in how LSTM work in image classification, allowing for a whole range of new research directions. For reproducibility purposes, we publish all our research code publicly.DEFT: distilling entangled factors by preventing information diffusionhttps://zbmath.org/1530.682122024-04-15T15:10:58.286558Z"Jiantao"https://zbmath.org/authors/?q=ai:jiantao."Wang, Lin"https://zbmath.org/authors/?q=ai:wang.lin.11"Yang, Bo"https://zbmath.org/authors/?q=ai:yang.bo.12"Li, Fanqi"https://zbmath.org/authors/?q=ai:li.fanqi"Liu, Chunxiuzi"https://zbmath.org/authors/?q=ai:liu.chunxiuzi"Zhou, Jin"https://zbmath.org/authors/?q=ai:zhou.jin.1Summary: Disentanglement is a highly desirable property of representation owing to its similarity to human understanding and reasoning. Many works achieve disentanglement upon information bottlenecks. Despite their elegant mathematical foundations, the IB branch usually exhibits lower performance. In order to provide an insight into the problem, we develop an annealing test to calculate the information freezing point (IFP), which is a transition state to freeze information into the latent variables. We also explore this clue or inductive bias for separating the entangled factors according to the differences in the IFP distributions. We found the existing approaches suffer from the information diffusion problem, according to which the increased information diffuses in all latent variables. Based on this insight, we propose a novel disentanglement framework, termed the distilling entangled factor (DEFT), to address the information diffusion problem by scaling backward information. DEFT applies a multistage training strategy, including multigroup encoders with different learning rates and piecewise pressure, to disentangle the factors stage by stage. We evaluate DEFT on three variants of dSprites and SmallNORB, which shows low-variance and high-level disentanglement scores. Furthermore, the experiment under the correlative factors demonstrates incapable of TC-based approaches. DEFT also exhibits a competitive performance in the unsupervised setting.A review of choice topics in quantum computing and some connections with machine learninghttps://zbmath.org/1530.682132024-04-15T15:10:58.286558Z"Khan, Faisal Shah"https://zbmath.org/authors/?q=ai:khan.faisal-shahSummary: Information technology, particularly computing, has seen two major developments in the past two decades. These developments are machine learning and quantum computing. This chapter is a review of some aspects of quantum computing and quantum machine learning. It reviews the two-slit experiment from quantum physics that is essential to understanding the basics of quantum computing. This will be followed by a mathematically more formal description of quantum computing with a discussion of the complex projective state space of quantum objects. Complex numbers are a generalization of real numbers, arising naturally from attempts to solve quadratic equations of the form \(x2+1=0\). The interpretation of these two complex numbers is that they represent a higher-order of probability, referred to as probability amplitude. It turns out that one can view the double-slit experiment as an electronic digital computer that uses the higher-order randomization of quantum objects as a resource, that is, a quantum computer.
For the entire collection see [Zbl 1523.68010].Manifold learning with arbitrary normshttps://zbmath.org/1530.682142024-04-15T15:10:58.286558Z"Kileel, Joe"https://zbmath.org/authors/?q=ai:kileel.joe"Moscovich, Amit"https://zbmath.org/authors/?q=ai:moscovich.amit"Zelesko, Nathan"https://zbmath.org/authors/?q=ai:zelesko.nathan"Singer, Amit"https://zbmath.org/authors/?q=ai:singer.amitSummary: Manifold learning methods play a prominent role in nonlinear dimensionality reduction and other tasks involving high-dimensional data sets with low intrinsic dimensionality. Many of these methods are graph-based: they associate a vertex with each data point and a weighted edge with each pair. Existing theory shows that the Laplacian matrix of the graph converges to the Laplace-Beltrami operator of the data manifold, under the assumption that the pairwise affinities are based on the Euclidean norm. In this paper, we determine the limiting differential operator for graph Laplacians constructed using \textit{any} norm. Our proof involves an interplay between the second fundamental form of the manifold and the convex geometry of the given norm's unit ball. To demonstrate the potential benefits of non-Euclidean norms in manifold learning, we consider the task of mapping the motion of large molecules with continuous variability. In a numerical simulation we show that a modified Laplacian eigenmaps algorithm, based on the Earthmover's distance, outperforms the classic Euclidean Laplacian eigenmaps, both in terms of computational cost and the sample size needed to recover the intrinsic geometry.Spectral banditshttps://zbmath.org/1530.682152024-04-15T15:10:58.286558Z"Kocák, Tomáš"https://zbmath.org/authors/?q=ai:kocak.tomas"Munos, Rémi"https://zbmath.org/authors/?q=ai:munos.remi"Kveton, Branislav"https://zbmath.org/authors/?q=ai:kveton.branislav"Agrawal, Shipra"https://zbmath.org/authors/?q=ai:agrawal.shipra"Valko, Michal"https://zbmath.org/authors/?q=ai:valko.michalSummary: Smooth functions on graphs have wide applications in manifold and semi-supervised learning. In this work, we study a bandit problem where the payoffs of arms are smooth on a graph. This framework is suitable for solving online learning problems that involve graphs, such as content-based recommendation. In this problem, each item we can recommend is a node of an undirected graph and its expected rating is similar to the one of its neighbors. The goal is to recommend items that have high expected ratings. We aim for the algorithms where the cumulative regret with respect to the optimal policy would not scale poorly with the number of nodes. In particular, we introduce the notion of an effective dimension, which is small in real-world graphs, and propose three algorithms for solving our problem that scale linearly and sublinearly in this dimension. Our experiments on content recommendation problem show that a good estimator of user preferences for thousands of items can be learned from just tens of node evaluations.Learning distributional programs for relational autocompletionhttps://zbmath.org/1530.682162024-04-15T15:10:58.286558Z"Kumar, Nitesh"https://zbmath.org/authors/?q=ai:kumar.nitesh"Kuželka, Ondřej"https://zbmath.org/authors/?q=ai:kuzelka.ondrej"De Raedt, Luc"https://zbmath.org/authors/?q=ai:de-raedt.lucSummary: Relational autocompletion is the problem of automatically filling out some missing values in multi-relational data. We tackle this problem within the probabilistic logic programming framework of \textit{Distributional Clauses} (DCs), which supports both discrete and continuous probability distributions. Within this framework, we introduce \textit{DiceML} -- an approach to learn both the structure and the parameters of DC programs from relational data (with possibly missing data). To realize this, \textit{DiceML} integrates statistical modeling and DCs with rule learning. The distinguishing features of \textit{DiceML} are that it (1) tackles autocompletion in relational data, (2) learns DCs extended with statistical models, (3) deals with both discrete and continuous distributions, (4) can exploit background knowledge, and (5) uses an expectation-maximization-based (EM) algorithm to cope with missing data. The empirical results show the promise of the approach, even when there is missing data.Adversarial strategy for transductive zero-shot learninghttps://zbmath.org/1530.682172024-04-15T15:10:58.286558Z"Liu, Youfa"https://zbmath.org/authors/?q=ai:liu.youfa"Du, Bo"https://zbmath.org/authors/?q=ai:du.bo"Ni, Fuchuan"https://zbmath.org/authors/?q=ai:ni.fuchuanSummary: Zero-shot learning (ZSL) realizes unseen object recognition by transferring knowledge from seen classes to unseen classes under common semantic space assumption, such as attribute space and semantic word vector space. Previous works used seen image feature and semantic representation but ignored unseen test image features to learn a projection from visual space to semantic space, which may lead to the domain shift problem, i.e., due to disjoint seen and unseen classes, the projection learnt from auxiliary dataset is biased when applied directly to the target dataset. In this paper, adversarial strategy is proposed with an instantiation to deal with domain shift problem. It is described as a two-player game in which player 1 is projector while player 2 is classifier. Projector expects to learn a projection from visual space to semantic space with good semantic preservation property while classifier expects to achieve high accuracy. The adversarial meaning comes from the design of parallel structure between loss function on training samples and that on test samples, semantic compatibility of these two loss functions and loss function in classifier, and distribution alignment. A theoretical analysis is provided and experiments are performed on benchmark datasets to ascertain the effectiveness of adversarial strategy.Securing machine learning models: notions and open issueshttps://zbmath.org/1530.682182024-04-15T15:10:58.286558Z"Mauri, Lara"https://zbmath.org/authors/?q=ai:mauri.lara"Damiani, Ernesto"https://zbmath.org/authors/?q=ai:damiani.ernestoSummary: Machine Learning (ML) models are taking the place of conventional algorithms in a wide range of application domains. However, once ML models have been deployed in the field, they can be attacked in ways that are very different from the ones of conventional systems. This chapter reviews some of the techniques that attackers use to compromise ML-based systems at two core phases of the learning process: the training and the inference stages. It provides an overview that, taking into account the current variety and scope of threats and attacks to ML models, will help the security analyst in charge of alleviating them. The chapter introduces some preliminary concepts, including the one of ML lifecycle. It then presents the setting of Adversarial Machine Learning from the point of view context of computer security, and discusses the notions of threats, vulnerabilities, and attacks. The chapter also details common alleviation measures against training-time attacks.
For the entire collection see [Zbl 1523.68010].Class imbalance learning using fuzzy ART and intuitionistic fuzzy twin support vector machineshttps://zbmath.org/1530.682192024-04-15T15:10:58.286558Z"Rezvani, Salim"https://zbmath.org/authors/?q=ai:rezvani.salim"Wang, Xizhao"https://zbmath.org/authors/?q=ai:wang.xizhao(no abstract)Automated granule discovery in continuous data for feature selectionhttps://zbmath.org/1530.682202024-04-15T15:10:58.286558Z"Sewwandi, M. A. N. D."https://zbmath.org/authors/?q=ai:sewwandi.m-a-n-d"Li, Yuefeng"https://zbmath.org/authors/?q=ai:li.yuefeng"Zhang, Jinglan"https://zbmath.org/authors/?q=ai:zhang.jinglan(no abstract)Functorial manifold learninghttps://zbmath.org/1530.682212024-04-15T15:10:58.286558Z"Shiebler, Dan"https://zbmath.org/authors/?q=ai:shiebler.danSummary: We adapt previous research on category theory and topological unsupervised learning to develop a functorial perspective on manifold learning, also known as nonlinear dimensionality reduction. We first characterize manifold learning algorithms as functors that map pseudometric spaces to optimization objectives and that factor through hierarchical clustering functors. We then use this characterization to prove refinement bounds on manifold learning loss functions and construct a hierarchy of manifold learning algorithms based on their equivariants. We express several popular manifold learning algorithms as functors at different levels of this hierarchy, including Metric Multidimensional Scaling, IsoMap, and UMAP. Next, we use interleaving distance to study the stability of a broad class of manifold learning algorithms. We present bounds on how closely the embeddings these algorithms produce from noisy data approximate the embeddings they would learn from noiseless data. Finally, we use our framework to derive a set of novel manifold learning algorithms, which we experimentally demonstrate are competitive with the state of the art.
For the entire collection see [Zbl 1522.68034].Mining topological structure in graphs through forest representationshttps://zbmath.org/1530.682222024-04-15T15:10:58.286558Z"Vandaele, Robin"https://zbmath.org/authors/?q=ai:vandaele.robin"Saeys, Yvan"https://zbmath.org/authors/?q=ai:saeys.yvan"De Bie, Tijl"https://zbmath.org/authors/?q=ai:de-bie.tijlSummary: We consider the problem of inferring simplified topological substructures -- which we term backbones -- in metric and non-metric graphs. Intuitively, these are subgraphs with `few' nodes, multifurcations, and cycles, that model the topology of the original graph well. We present a multistep procedure for inferring these backbones. First, we encode local (geometric) information of each vertex in the original graph by means of the boundary coefficient (BC) to identify `core' nodes in the graph. Next, we construct a forest representation of the graph, termed an \(f\)-pine, that connects every node of the graph to a local `core' node. The final backbone is then inferred from the \(f\)-pine through CLOF (Constrained Leaves Optimal subForest), a novel graph optimization problem we introduce in this paper. On a theoretical level, we show that CLOF is NP-hard for general graphs. However, we prove that CLOF can be efficiently solved for forest graphs, a surprising fact given that CLOF induces a nontrivial monotone submodular set function maximization problem on tree graphs. This result is the basis of our method for mining backbones in graphs through forest representation. We qualitatively and quantitatively confirm the applicability, effectiveness, and scalability of our method for discovering backbones in a variety of graph-structured data, such as social networks, earthquake locations scattered across the Earth, and high-dimensional cell trajectory data.Privacy-preserving regression algorithm based on proximal support vector machinehttps://zbmath.org/1530.682232024-04-15T15:10:58.286558Z"Wu, Jue"https://zbmath.org/authors/?q=ai:wu.jue"Yang, Lei"https://zbmath.org/authors/?q=ai:yang.lei.3"Yang, Fu Jun"https://zbmath.org/authors/?q=ai:yang.fujun"Zhang, Pei Hong"https://zbmath.org/authors/?q=ai:zhang.peihong"Liu, Haohuai"https://zbmath.org/authors/?q=ai:liu.haohuai"Bai, Ke Qiang"https://zbmath.org/authors/?q=ai:bai.keqiangSummary: With the advent of the big data era, the privacy-preserving data mining is gaining a significant importance. The present study envisaged the development of a privacy-preserving data mining, based on the proximal support vector regression (PPSVR). The algorithm was based on a distributed system, and it was shown that the global kernel could be calculated by the local kernel. In order to protect the data privacy, the stochastic noise was added to the original data on each data set, and each participant had to provide only the disturbed local kernel. Furthermore, simulation experiments were performed on the algorithm and the results indicated that the accuracy of the PPSVR was almost equal to the proximal support vector regression algorithm (PSVR). The algorithm takes advantage of the speed of the PSVR, and the experimental validation showed that the speed of the PPSVR was faster than the support vector regression (SVR).An optimised FP-growth algorithm using MapReduce paradigmshttps://zbmath.org/1530.682242024-04-15T15:10:58.286558Z"Wu, Xiuguo"https://zbmath.org/authors/?q=ai:wu.xiuguo(no abstract)Zero-shot learning via the fusion of generation and embedding for image recognitionhttps://zbmath.org/1530.682252024-04-15T15:10:58.286558Z"Zhao, Peng"https://zbmath.org/authors/?q=ai:zhao.peng.2"Zhang, Siying"https://zbmath.org/authors/?q=ai:zhang.siying"Liu, Jinhui"https://zbmath.org/authors/?q=ai:liu.jinhui"Liu, Huiting"https://zbmath.org/authors/?q=ai:liu.huiting(no abstract)Deep neural networks pruning via the structured perspective regularizationhttps://zbmath.org/1530.682262024-04-15T15:10:58.286558Z"Cacciola, Matteo"https://zbmath.org/authors/?q=ai:cacciola.matteo"Frangioni, Antonio"https://zbmath.org/authors/?q=ai:frangioni.antonio"Li, Xinlin"https://zbmath.org/authors/?q=ai:li.xinlin"Lodi, Andrea"https://zbmath.org/authors/?q=ai:lodi.andreaSummary: In machine learning, artificial neural networks (ANNs) are a very powerful tool, broadly used in many applications. Often, the selected (deep) architectures include many layers, and therefore a large number of parameters, which makes training, storage, and inference expensive. This motivated a stream of research about compressing the original networks into smaller ones without excessively sacrificing performances. Among the many proposed compression approaches, one of the most popular is \textit{pruning}, whereby entire elements of the ANN (links, nodes, channels, \dots) and the corresponding weights are deleted. Since the nature of the problem is inherently combinatorial (what elements to prune and what not), we propose a new pruning method based on operational research tools. We start from a natural mixed-integer-programming model for the problem, and we use the perspective reformulation technique to strengthen its continuous relaxation. Projecting away the indicator variables from this reformulation yields a new regularization term, which we call the structured perspective regularization, that leads to structured pruning of the initial architecture. We test our method on some ResNet architectures applied to CIFAR-10, CIFAR-100, and ImageNet datasets, obtaining competitive performances w.r.t. the state of the art for structured pruning.SepNet: a neural network for directionally correlated datahttps://zbmath.org/1530.682272024-04-15T15:10:58.286558Z"Gao, Fuchang"https://zbmath.org/authors/?q=ai:gao.fuchang"Ma, Yiqing"https://zbmath.org/authors/?q=ai:ma.yiqing"Zhang, Boyu"https://zbmath.org/authors/?q=ai:zhang.boyu"Xian, Min"https://zbmath.org/authors/?q=ai:xian.minSummary: Multi-dimensional tensor data appear in diverse settings, including multichannel signals, spectrograms, and hyperspectral data from remote sensing. In many cases, these data are directionally correlated, \textit{i.e.} the correlation between variables from different dimensions is significantly weaker than the correlation between variables from the same dimension. Convolutional neural networks are readily applicable to directionally correlated data but are often inefficient, as they impose many unnecessary connections between neurons. Here we propose a novel architecture, SepNet, specifically for directionally correlated datasets. SepNet uses directional operators to extract directional features from each dimension separately, followed by a linear operator along the depth to generate higher-level features from the directional features. Experiments on two representative directionally correlated datasets showed that SepNet improved network efficiency up to 100-fold while maintaining high accuracy comparable with state-of-the-art convolutional neural network models. Furthermore, SepNet can be flexibly constructed with minimal restriction on the output shape of each layer. These results reveal the potential of data-specific architecting of neural networks.Multicriteria optimization in deep learninghttps://zbmath.org/1530.682282024-04-15T15:10:58.286558Z"Repetto, Marco"https://zbmath.org/authors/?q=ai:repetto.marco"La Torre, Davide"https://zbmath.org/authors/?q=ai:la-torre.davideSummary: Artificial Intelligence (AI) is now widely accepted as an interdisciplinary field encompassing biology, computer science, philosophy, mathematics, engineering and robotics, and cognitive science that is concerned with simulating human intelligence using computer-based technologies. Machine Learning (ML) is a branch of AI that focuses on algorithms that learn from data and make future predictions and judgments on the data. In recent years Deep Learning (DL) algorithms have become the state of the art for supervised learning tasks such as image classification and natural language processing. DL is a branch of ML that uses Artificial Neural Networks to learn high-level abstractions from data. This chapter presents the DL paradigm and the recent neural network architectures used nowadays. DL is a subfield of ML in which data is automatically evaluated and translated into rules that can be used by a computer to generate predictions.
For the entire collection see [Zbl 1523.68010].Artificial neural networks with conformable transfer function for improving the performance in thermal and environmental processeshttps://zbmath.org/1530.682292024-04-15T15:10:58.286558Z"Solís-Pérez, J. E."https://zbmath.org/authors/?q=ai:solis-perez.jesus-emmanuel"Hernández, J. A."https://zbmath.org/authors/?q=ai:hernandez.joshua-a|hernandez.juan-antonio|hernandez.jesus-a|hernandez.jorge-antonio-rodriguez|hernandez.jose-antonio|hernandez.joseph-a|hernandez.jose-alberto|hernandez.julio-a"Parrales, A."https://zbmath.org/authors/?q=ai:parrales.a"Gómez-Aguilar, J. F."https://zbmath.org/authors/?q=ai:gomez-aguilar.jose-francisco"Huicochea, A."https://zbmath.org/authors/?q=ai:huicochea.aSummary: This research proposes a novel transfer function based on the hyperbolic tangent and the Khalil conformable exponential function. The non-integer order transfer function offers a suitable neural network configuration because of its ability to adapt. Consequently, this function was introduced into neural network models for three experimental cases: estimating the annular Nusselt number correlation to a helical double-pipe evaporator, the volumetric mass transfer coefficient in an electrochemical reaction, and the thermal efficiency of a solar parabolic trough collector. We found the new transfer function parameters during the training step of the neural networks. Therefore, weights and biases depend on them. We assessed the models applied to the three cases using the determination coefficient, adjusted determination coefficient, and the slope-intercept test. In addition, the MSE for the training set and the whole database were computed to show that there is no overfitting problem. The best-assessed models showed a relationship of 99\%, 97\%, and 95\% with the experimental data for the first, second, and third cases. This novel proposal made reducing the number of neurons in the hidden layer feasible. Therefore, we show a neural network with a conformable transfer function (ANN-CTF) that learns well enough with less available information from the experimental database during its training.Learners' languageshttps://zbmath.org/1530.682302024-04-15T15:10:58.286558Z"Spivak, David I."https://zbmath.org/authors/?q=ai:spivak.david-iSummary: In [``Backprop as functor: a compositional perspective on supervised learning'', Preprint, \url{arXiv:1711.10455}], \textit{B. Fong} et al. show that the fundamental elements of deep learning -- gradient descent and backpropagation -- can be conceptualized as a strong monoidal functor \(\mathbf{Para}(\mathbf{Euc})\to\mathbf{Learn}\) from the category of parameterized Euclidean spaces to that of learners, a category developed explicitly to capture parameter update and backpropagation. It was soon realized that there is an isomorphism \(\mathbf{Learn}\cong\mathbf{Para}(\mathbf{SLens})\), where \(\mathbf{SLens}\) is the symmetric monoidal category of simple lenses as used in functional programming.
In this note, we observe that \(\mathbf{SLens}\) is a full subcategory of \(\mathbf{Poly}\), the category of polynomial functors in one variable, via the functor \(A\mapsto Ay^A\). Using the fact that \((\mathbf{Poly}, \otimes)\) is monoidal closed, we show that a map \(A\to B\) in \(\mathbf{Para}(\mathbf{SLens})\) has a natural interpretation in terms of dynamical systems (more precisely, generalized Moore machines) whose interface is the internal-hom type \([Ay^A, By^B]\).
Finally, we review the fact that the category \(p\)-\(\mathbf{Coalg}\) of dynamical systems on any \(p\in\mathbf{Poly}\) forms a topos, and consider the logical propositions that can be stated in its internal language. We give gradient descent as an example, and we conclude by discussing some directions for future work.
For the entire collection see [Zbl 1522.68034].Design of continuous-time recurrent neural networks with piecewise-linear activation function for generation of prescribed sequences of bipolar vectorshttps://zbmath.org/1530.682312024-04-15T15:10:58.286558Z"Takahashi, Norikazu"https://zbmath.org/authors/?q=ai:takahashi.norikazu"Yamakawa, Tsuyoshi"https://zbmath.org/authors/?q=ai:yamakawa.tsuyoshi"Minetoma, Yasuhiro"https://zbmath.org/authors/?q=ai:minetoma.yasuhiro"Nishi, Tetsuo"https://zbmath.org/authors/?q=ai:nishi.tetsuo"Migita, Tsuyoshi"https://zbmath.org/authors/?q=ai:migita.tsuyoshiRecurrent neural networks (RNNs) have been studied for many years due to their many important applications in subjects varying from combinatorial optimization, image processing, acoustic modeling, language processing and many more. We refer the reader to the paper for an extensive literature review in this regard and also for a excellent reference list regarding recent advances in the study and applications of RNNs. This interesting paper focuses on a continuous-time RNN model with a piecewise-linear activation function that has neither external inputs nor hidden neurons, and studies the problem of finding the parameters of the model so that it generates a given sequence of bipolar vectors. The authors provide a sufficient condition for their model to generate their desired sequence of bipolar vectors which is expressed as a system of linear inequalities in the parameters. The authors provide three interesting approaches to finding solutions of this system of linear inequalities. One approach is via a convex quadratic programming method and the other two via linear programming problems. As a result, two types of sequences of bipolar vectors for their model are generated. The case where the model generates a periodic sequence of bipolar vectors is also studied, and a sufficient condition for the trajectory of the state vector to converge to a limit cycle is given.
This paper is well written, with ample references and presents a nice theoretical framework to solve a difficult and interesting problem.
Reviewer: Steven B. Damelin (Ann Arbor)Understanding and mitigating gradient flow pathologies in physics-informed neural networkshttps://zbmath.org/1530.682322024-04-15T15:10:58.286558Z"Wang, Sifan"https://zbmath.org/authors/?q=ai:wang.sifan"Teng, Yujun"https://zbmath.org/authors/?q=ai:teng.yujun"Perdikaris, Paris"https://zbmath.org/authors/?q=ai:perdikaris.paris-gSummary: The widespread use of neural networks across different scientific domains often involves constraining them to satisfy certain symmetries, conservation laws, or other domain knowledge. Such constraints are often imposed as soft penalties during model training and effectively act as domain-specific regularizers of the empirical risk loss. Physics-informed neural networks is an example of this philosophy in which the outputs of deep neural networks are constrained to approximately satisfy a given set of partial differential equations. In this work we review recent advances in scientific machine learning with a specific focus on the effectiveness of physics-informed neural networks in predicting outcomes of physical systems and discovering hidden physics from noisy data. We also identify and analyze a fundamental mode of failure of such approaches that is related to numerical stiffness leading to unbalanced back-propagated gradients during model training. To address this limitation we present a learning rate annealing algorithm that utilizes gradient statistics during model training to balance the interplay between different terms in composite loss functions. We also propose a novel neural network architecture that is more resilient to such gradient pathologies. Taken together, our developments provide new insights into the training of constrained neural networks and consistently improve the predictive accuracy of physics-informed neural networks by a factor of \(50-100 \times\) across a range of problems in computational physics. All code and data accompanying this manuscript are publicly available at \url{https://github.com/PredictiveIntelligenceLab/GradientPathologiesPINNs}.Convergence of deep convolutional neural networkshttps://zbmath.org/1530.682332024-04-15T15:10:58.286558Z"Xu, Yuesheng"https://zbmath.org/authors/?q=ai:xu.yuesheng"Zhang, Haizhang"https://zbmath.org/authors/?q=ai:zhang.haizhangSummary: Convergence of deep neural networks as the depth of the networks tends to infinity is fundamental in building the mathematical foundation for deep learning. In a previous study, we investigated this question for deep networks with the Rectified Linear Unit (ReLU) activation function and with a fixed width. This does not cover the important convolutional neural networks where the widths are increased from layer to layer. For this reason, we first study convergence of general ReLU networks with increased widths and then apply the results obtained to deep convolutional neural networks. It turns out the convergence reduces to convergence of infinite products of matrices with increased sizes, which has not been considered in the literature. We establish sufficient conditions for convergence of such infinite products of matrices. Based on the conditions, we present sufficient conditions for pointwise convergence of general deep ReLU networks with increasing widths, and as well as pointwise convergence of deep ReLU convolutional neural networks.Successfully and efficiently training deep multi-layer perceptrons with logistic activation function simply requires initializing the weights with an appropriate negative meanhttps://zbmath.org/1530.682342024-04-15T15:10:58.286558Z"Yilmaz, Ahmet"https://zbmath.org/authors/?q=ai:yilmaz.ahmet"Poli, Riccardo"https://zbmath.org/authors/?q=ai:poli.riccardoSummary: The vanishing gradient problem (i.e., gradients prematurely becoming extremely small during training, thereby effectively preventing a network from learning) is a long-standing obstacle to the training of deep neural networks using sigmoid activation functions when using the standard back-propagation algorithm. In this paper, we found that an important contributor to the problem is weight initialization.
We started by developing a simple theoretical model showing how the expected value of gradients is affected by the mean of the initial weights. We then developed a second theoretical model that allowed us to identify a sufficient condition for the vanishing gradient problem to occur. Using these theories we found that initial back-propagation gradients do not vanish if the mean of the initial weights is negative and inversely proportional to the number of neurons in a layer.
Numerous experiments with networks with 10 and 15 hidden layers corroborated the theoretical predictions: If we initialized weights as indicated by the theory, the standard back-propagation algorithm was both highly successful and efficient at training deep neural networks using sigmoid activation functions.Transductive semantic knowledge graph propagation for zero-shot learninghttps://zbmath.org/1530.682352024-04-15T15:10:58.286558Z"Zhang, Hai-gang"https://zbmath.org/authors/?q=ai:zhang.haigang"Que, Hao-yi"https://zbmath.org/authors/?q=ai:que.haoyi"Ren, Jin"https://zbmath.org/authors/?q=ai:ren.jin"Wu, Zheng-guang"https://zbmath.org/authors/?q=ai:wu.zhengguangSummary: The domain shift is a very common phenomenon in zero-shot learning (ZSL), because the data distribution between the source and target domain might not match well in real scenarios. This paper focuses on dealing with the domain drift problem in ZSL based on the semantic knowledge graph propagation. Our method consists of visual feature extraction (VFE) module, semantic feature extraction module (SFE) and feature mapping module (FM). In VFE module, the high-level visual features are extracted under Convolutional Neural Network (CNN) framework, where unseen samples participate in model training and stay away from seen ones under the premise of distinguishability. SFE module relies on the Graph Convolutional Network (GCN) framework and focuses on the transmission of semantic embeddings. A modified message aggregation and transformation strategy is proposed to effectively relieve the information smoothing phenomenon caused by the increase of GCN layers. In the recognition stage, AutoEncoder framework achieves a two-way visual and semantic interaction to further minimize the domain drift phenomenon. Simulation results on ImageNet dataset have demonstrated the performance of the proposed method.Towards understanding theoretical advantages of complex-reaction networkshttps://zbmath.org/1530.682362024-04-15T15:10:58.286558Z"Zhang, Shao-Qun"https://zbmath.org/authors/?q=ai:zhang.shao-qun"Gao, Wei"https://zbmath.org/authors/?q=ai:gao.wei.5"Zhou, Zhi-Hua"https://zbmath.org/authors/?q=ai:zhou.zhihuaSummary: Complex-valued neural networks have attracted increasing attention in recent years, while it remains open on the advantages of complex-valued neural networks in comparison with real-valued networks. This work takes one step on this direction by introducing the \textit{complex-reaction network} with fully-connected feed-forward architecture. We prove the universal approximation property for complex-reaction networks, and show that a class of radial functions can be approximated by a complex-reaction network using the polynomial number of parameters, whereas real-valued networks need at least exponential parameters to reach the same approximation level. For empirical risk minimization, we study the landscape and convergence of complex gradient descents. Our theoretical result shows that the critical point set of complex-reaction networks is a proper subset of that of real-valued networks, which may show some insights on finding the optimal solutions more easily for complex-reaction networks.From geometry to topology: inverse theorems for distributed persistencehttps://zbmath.org/1530.682372024-04-15T15:10:58.286558Z"Solomon, Elchanan"https://zbmath.org/authors/?q=ai:solomon.elchanan"Wagner, Alexander"https://zbmath.org/authors/?q=ai:wagner.alexander-j|wagner.alexander-y|wagner.alexander-k"Bendich, Paul"https://zbmath.org/authors/?q=ai:bendich.paulSummary: What is the ``right'' topological invariant of a large point cloud X? Prior research has focused on estimating the full persistence diagram of X, a quantity that is very expensive to compute, unstable to outliers, and far from injective. We therefore propose that, in many cases, the collection of persistence diagrams of many small subsets of X is a better invariant. This invariant, which we call ``distributed persistence,'' is perfectly parallelizable, more stable to outliers, and has a rich inverse theory. The map from the space of metric spaces (with the quasi-isometry distance) to the space of distributed persistence invariants (with the Hausdorff-Bottleneck distance) is globally bi-Lipschitz. This is a much stronger property than simply being injective, as it implies that the inverse image of a small neighborhood is a small neighborhood, and is to our knowledge the only result of its kind in the TDA literature. Moreover, the inverse Lipschitz constant depends on the size of the subsets taken, so that as the size of these subsets goes from small to large, the invariant interpolates between a purely geometric one and a topological one. Lastly, we note that our inverse results do not actually require considering all subsets of a fixed size (an enormous collection), but a relatively small collection satisfying simple covering properties. These theoretical results are complemented by synthetic experiments demonstrating the use of distributed persistence in practice.Controller synthesis for timeline-based gameshttps://zbmath.org/1530.682382024-04-15T15:10:58.286558Z"Acampora, Renato"https://zbmath.org/authors/?q=ai:acampora.renato"Geatti, Luca"https://zbmath.org/authors/?q=ai:geatti.luca"Gigante, Nicola"https://zbmath.org/authors/?q=ai:gigante.nicola"Montanari, Angelo"https://zbmath.org/authors/?q=ai:montanari.angelo"Picotti, Valentino"https://zbmath.org/authors/?q=ai:picotti.valentinoSummary: In the timeline-based approach to planning, originally born in the space sector, the evolution over time of a set of state variables (the timelines) is governed by a set of temporal constraints. Traditional timeline-based planning systems excel at the integration of planning with execution by handling \textit{temporal uncertainty}. In order to handle general nondeterminism as well, the concept of \textit{timeline-based games} has been recently introduced. It has been proved that finding whether a winning strategy exists for such games is \textsf{2EXPTIME}-complete. However, a concrete approach to synthesize controllers implementing such strategies is missing. This paper fills this gap, outlining an approach to controller synthesis for timeline-based games.
For the entire collection see [Zbl 1522.68028].Evolving graphs with semantic neutral drifthttps://zbmath.org/1530.682392024-04-15T15:10:58.286558Z"Atkinson, Timothy"https://zbmath.org/authors/?q=ai:atkinson.timothy"Plump, Detlef"https://zbmath.org/authors/?q=ai:plump.detlef"Stepney, Susan"https://zbmath.org/authors/?q=ai:stepney.susan(no abstract)GSA improvement via the von Neumann stability analysishttps://zbmath.org/1530.682402024-04-15T15:10:58.286558Z"Naâs, Ihcène"https://zbmath.org/authors/?q=ai:naas.ihcene"Kessentini, Sameh"https://zbmath.org/authors/?q=ai:kessentini.sameh(no abstract)Using a SAT solver to find interesting sets of nonstandard dicehttps://zbmath.org/1530.682412024-04-15T15:10:58.286558Z"Purcell, Michael"https://zbmath.org/authors/?q=ai:purcell.michaelSummary: We describe a family of Boolean satisfiability (SAT) problems for which each solution corresponds to a unique set of nonstandard dice. We show that we can control the relationships between the dice in each solution by imposing a set of cardinality constraints on the variables in the corresponding SAT problem. We then present examples of interesting sets of nonstandard dice that we found by solving such problems. In particular, we describe a set of 19 five-sided dice that realize the Paley tournament on 19 vertices. Furthermore, we show that this set of dice is minimal in the sense that no set of 19 dice with less than five sides can realize the Paley tournament on 19 vertices.Modeling and reasoning in event calculus using goal-directed constraint answer set programminghttps://zbmath.org/1530.682422024-04-15T15:10:58.286558Z"Arias, Joaquín"https://zbmath.org/authors/?q=ai:arias.joaquin"Carro, Manuel"https://zbmath.org/authors/?q=ai:carro.manuel"Chen, Zhuo"https://zbmath.org/authors/?q=ai:chen.zhuo.1"Gupta, Gopal"https://zbmath.org/authors/?q=ai:gupta.gopalSummary: Automated commonsense reasoning (CR) is essential for building human-like AI systems featuring, for example, explainable AI. Event calculus (EC) is a family of formalisms that model CR with a sound, logical basis. Previous attempts to mechanize reasoning using EC faced difficulties in the treatment of the continuous change in dense domains (e.g. time and other physical quantities), constraints among variables, default negation, and the uniform application of different inference methods, among others. We propose the use of s(CASP), a query-driven, top-down execution model for Predicate Answer Set Programming with Constraints, to model and reason using EC. We show how EC scenarios can be naturally and directly encoded in s(CASP) and how it enables deductive and abductive reasoning tasks in domains featuring constraints involving both dense time and dense fluents.Efficient TBox reasoning with value restrictions using the \(\mathcal{FL}_0 \mathit{wer}\) reasonerhttps://zbmath.org/1530.682432024-04-15T15:10:58.286558Z"Baader, Franz"https://zbmath.org/authors/?q=ai:baader.franz"Koopmann, Patrick"https://zbmath.org/authors/?q=ai:koopmann.patrick"Michel, Friedrich"https://zbmath.org/authors/?q=ai:michel.friedrich"Turhan, Anni-Yasmin"https://zbmath.org/authors/?q=ai:turhan.anni-yasmin"Zarriess, Benjamin"https://zbmath.org/authors/?q=ai:zarriess.benjaminSummary: The inexpressive Description Logic (DL) \(\mathcal{FL}_0\) , which has conjunction and value restriction as its only concept constructors, had fallen into disrepute when it turned out that reasoning in \(\mathcal{FL}_0\) w.r.t. general TBoxes is \textsc{ExpTime}-complete, that is, as hard as in the considerably more expressive logic \(\mathcal{ALC}\) . In this paper, we rehabilitate \(\mathcal{FL}_0\) by presenting a dedicated subsumption algorithm for \(\mathcal{FL}_0\) , which is much simpler than the tableau-based algorithms employed by highly optimized DL reasoners. Our experiments show that the performance of our novel algorithm, as prototypically implemented in our \(\mathcal{FL}_0 \mathit{wer}\) reasoner, compares very well with that of the highly optimized reasoners. \(\mathcal{FL}_0 \mathit{wer}\) can also deal with ontologies written in the extension \(\mathcal{FL}_\bot\) of \(\mathcal{FL}_0\) with the top and the bottom concept by employing a polynomial-time reduction, shown in this paper, which eliminates top and bottom. We also investigate the complexity of reasoning in DLs related to the Horn-fragments of \(\mathcal{FL}_0\) and \(\mathcal{FL}_\bot\).Reasoning on \(\mathit{DL}\)-\(\mathit{Lite}_{\mathcal{R}}\) with defeasibility in ASPhttps://zbmath.org/1530.682442024-04-15T15:10:58.286558Z"Bozzato, Loris"https://zbmath.org/authors/?q=ai:bozzato.loris"Eiter, Thomas"https://zbmath.org/authors/?q=ai:eiter.thomas"Serafini, Luciano"https://zbmath.org/authors/?q=ai:serafini.lucianoSummary: Reasoning on defeasible knowledge is a topic of interest in the area of description logics, as it is related to the need of representing exceptional instances in knowledge bases. In this direction, in our previous works we presented a framework for representing (contextualized) OWL RL knowledge bases with a notion of justified exceptions on defeasible axioms: reasoning in such framework is realized by a translation into ASP programs. The resulting reasoning process for OWL RL, however, introduces a complex encoding in order to capture reasoning on the negative information needed for reasoning on exceptions. In this paper, we apply the justified exception approach to knowledge bases in \(\mathit{DL}\)-\(\mathit{Lite}_{\mathcal{R}}\), that is, the language underlying OWL QL. We provide a definition for \(\mathit{DL}\)-\(\mathit{Lite}_{\mathcal{R}}\) knowledge bases with defeasible axioms and study their semantic and computational properties. In particular, we study the effects of exceptions over unnamed individuals. The limited form of \(\mathit{DL}\)-\(\mathit{Lite}_{\mathcal{R}}\) axioms allows us to formulate a simpler ASP encoding, where reasoning on negative information is managed by direct rules. The resulting materialization method gives rise to a complete reasoning procedure for instance checking in \(\mathit{DL}\)-\(\mathit{Lite}_{\mathcal{R}}\) with defeasible axioms.A filtering-based general approach to learning rational constraints of epistemic graphshttps://zbmath.org/1530.682452024-04-15T15:10:58.286558Z"Chi, Xiao"https://zbmath.org/authors/?q=ai:chi.xiaoSummary: Epistemic graphs are a generalization of the epistemic approach to probabilistic argumentation. Hunter proposed a 2-way generalization framework to learn epistemic constraints from crowd-sourcing data. However, the learnt epistemic constraints only reflect users' beliefs from data, without considering the rationality encoded in epistemic graphs. Meanwhile, the current framework can only generate epistemic constraints that reflect whether an agent believes an argument, but not the degree to which it believes in it. The major challenge to achieving this effect is that the time performance will become unacceptable when the number of restricted values increase. To address these problems, we propose a filtering-based approach using a multiple-way generalization step to generate a set of rational rules which are consistent with their epistemic graphs from a dataset. This approach is able to learn a wider variety of rational rules that reflect information in both the domain model and the users model, and therefore more suitable to be applied to some situations, e.g. automated persuasion system, where the statistical information about the beliefs of a group of users is exploited to predict the behaviours of a specific user. Moreover, to improve computational efficiency, we introduce a new function to exclude meaningless rules. The empirical results show that our approach significantly outperforms the existing framework when expanding the variety of rules.
For the entire collection see [Zbl 1528.03006].A logic for preference lifting under uncertainty and its decidabilityhttps://zbmath.org/1530.682462024-04-15T15:10:58.286558Z"Fu, Xiaoxuan"https://zbmath.org/authors/?q=ai:fu.xiaoxuan"Zhao, Zhiguang"https://zbmath.org/authors/?q=ai:zhao.zhiguangSummary: This paper explores the idea of the preference lifting under uncertainty. An attempt is proposed in the direction of ``qualitative = qualitative + quantitative''. This leads to a novel lifting called the ``pairwise lifting method''. It defines a \(\lambda\) function to record the number of occurrences of ``\( \ge \) -binary relation'' and ``\( \le \) -binary relation'' between individuals, and the preference relation between sets of individuals can be defined. We consider the logic of preference lifting of arbitrary preference relations, and prove its decidability by two methods, namely reduction to Presburger arithmetic and reduction to linear integer arithmetic.
For the entire collection see [Zbl 1528.03006].Harnessing incremental answer set solving for reasoning in assumption-based argumentationhttps://zbmath.org/1530.682472024-04-15T15:10:58.286558Z"Lehtonen, Tuomo"https://zbmath.org/authors/?q=ai:lehtonen.tuomo"Wallner, Johannes P."https://zbmath.org/authors/?q=ai:wallner.johannes-peter"Järvisalo, Matti"https://zbmath.org/authors/?q=ai:jarvisalo.mattiSummary: Assumption-based argumentation (ABA) is a central structured argumentation formalism. As shown recently, answer set programming (ASP) enables efficiently solving NP-hard reasoning tasks of ABA in practice, in particular in the commonly studied logic programming fragment of ABA. In this work, we harness recent advances in incremental ASP solving for developing effective algorithms for reasoning tasks in the logic programming fragment of ABA that are presumably hard for the second level of the polynomial hierarchy, including skeptical reasoning under preferred semantics as well as preferential reasoning. In particular, we develop non-trivial counterexample-guided abstraction refinement procedures based on incremental ASP solving for these tasks. We also show empirically that the procedures are significantly more effective than previously proposed algorithms for the tasks.Here and there with arithmetichttps://zbmath.org/1530.682482024-04-15T15:10:58.286558Z"Lifschitz, Vladimir"https://zbmath.org/authors/?q=ai:lifschitz.vladimirSummary: In the theory of answer set programming, two groups of rules are called strongly equivalent if, informally speaking, they have the same meaning in any context. The relationship between strong equivalence and the propositional logic of here-and-there allows us to establish strong equivalence by deriving rules of each group from rules of the other. In the process, rules are rewritten as propositional formulas. We extend this method of proving strong equivalence to an answer set programming language that includes operations on integers. The formula representing a rule in this language is a first-order formula that may contain comparison symbols among its predicate constants, and symbols for arithmetic operations among its function constants. The paper is under consideration for acceptance in TPLP.A topos-based approach to building language ontologieshttps://zbmath.org/1530.682492024-04-15T15:10:58.286558Z"Babonnaud, William"https://zbmath.org/authors/?q=ai:babonnaud.williamSummary: A common tendency in lexical semantics is to assume the existence of a hierarchy of types for fine-grained analyses of semantic phenomena. This paper provides a formal account of the existence of such a structure. A type system based on the categorical notion of topos is introduced, and is shown to be possibly adaptable to several existing formal approaches where such hierarchies are used. A refinement of the type hierarchy based on Fred Sommers' ontological theory is also proposed.
For the entire collection see [Zbl 1419.68004].Temporal minimal-world query answering over sparse ABoxeshttps://zbmath.org/1530.682502024-04-15T15:10:58.286558Z"Borgwardt, Stefan"https://zbmath.org/authors/?q=ai:borgwardt.stefan"Forkel, Walter"https://zbmath.org/authors/?q=ai:forkel.walter"Kovtunova, Alisa"https://zbmath.org/authors/?q=ai:kovtunova.alisaSummary: Ontology-mediated query answering is a popular paradigm for enriching answers to user queries with background knowledge. For querying the \textit{absence} of information, however, there exist only few ontology-based approaches. Moreover, these proposals conflate the closed-domain and closed-world assumption and, therefore, are not suited to deal with the anonymous objects that are common in ontological reasoning. Many real-world applications, like processing electronic health records, also contain a temporal dimension and require efficient reasoning algorithms. Moreover, since medical data are not recorded on a regular basis, reasoners must deal with sparse data with potentially large temporal gaps. Our contribution consists of two main parts: In the first part, we introduce a new closed-world semantics for answering conjunctive queries (CQs) with negation over ontologies formulated in the description logic \(\mathcal{ELH}_\bot\) , which is based on the \textit{minimal} canonical model. We propose a rewriting strategy for dealing with negated query atoms, which shows that query answering is possible in polynomial time in data complexity. In the second part, we extend this minimal-world semantics for answering metric temporal CQs with negation over the lightweight temporal logic \(\mathcal{TELH}_\bot^{\lozenge, \mathrm{lhs}, -}\) and obtain similar rewritability and complexity results.On algebraic approach of R. Wille and B. Ganter in the investigation of textshttps://zbmath.org/1530.682512024-04-15T15:10:58.286558Z"Bykova, Valentina V."https://zbmath.org/authors/?q=ai:bykova.valentina-vladimirovna"Mongush, Choduraa M."https://zbmath.org/authors/?q=ai:mongush.choduraa-mSummary: The statement of the problem of a binary classification by precedents using formal concept lattices is given, in which the initial data are two binary contexts. It is specified that this problem is intractable due to the high computational complexity of discovery process of the formal concept and constructing for them of the lattices. The decomposition reception, which allows reducing the computational complexity of this process is proposed and theoretically justified. The reduction of computational complexity is achieved by separation of every initial context on polynomial number of boxes (subcontexts), followed by a search of the formal concepts in each selected box. The results of computational experiments are presented and they confirm the effectiveness of the proposed of reception of the reducing computational complexity.Incremental construction of three-way concept lattice for knowledge discovery in social networkshttps://zbmath.org/1530.682522024-04-15T15:10:58.286558Z"Hao, Fei"https://zbmath.org/authors/?q=ai:hao.fei"Yang, Yixuan"https://zbmath.org/authors/?q=ai:yang.yixuan"Min, Geyong"https://zbmath.org/authors/?q=ai:min.geyong"Loia, Vincenzo"https://zbmath.org/authors/?q=ai:loia.vincenzoSummary: Three-way concept analysis (3WCA), a combination of three-way decision and formal concept analysis, is widely used in the field of knowledge discovery. Generally, constructing three-way concept lattices requires the original formal context and its complement context simultaneously. Additionally, the existing three-way concept lattice construction algorithms focus on the static formal context, and cannot cope with the dynamic formal context that is an essential representation in social networks. Toward this end, this paper pioneers a novel problem and method for the incremental construction of three-way concept lattice for knowledge discovery in social networks. Aiming to facilitate the construction efficiency, this paper firstly investigates the three-way concept lattice construction for attribute-incremental/object-incremental formal contexts, respectively. Then, the dynamic formal context of a social network can be viewed as a special formal context with both attribute-increment and object-increment. Further, we develop the AE/OE concept lattice incremental construction algorithms, called SNS-AE and SNS-OE. Extensive experiments are conducted on various formal contexts to evaluate the effectiveness of our incremental algorithms. The experimental results demonstrate that our proposed incremental algorithms can significantly decrease the construction time of three-way concept lattice compared to the non-incremental algorithm.Alternating fixpoint operator for hybrid MKNF knowledge bases as an approximator of AFThttps://zbmath.org/1530.682532024-04-15T15:10:58.286558Z"Liu, Fangfang"https://zbmath.org/authors/?q=ai:liu.fangfang"You, Jia-Huai"https://zbmath.org/authors/?q=ai:you.jia-huaiSummary: Approximation fixpoint theory (AFT) provides an algebraic framework for the study of fixpoints of operators on bilattices and has found its applications in characterizing semantics for various classes of logic programs and nonmonotonic languages. In this paper, we show one more application of this kind: the alternating fixpoint operator by Knorr et al. for the study of the well-founded semantics for hybrid minimal knowledge and negation as failure (MKNF) knowledge bases is in fact an approximator of AFT in disguise, which, thanks to the abstraction power of AFT, characterizes not only the well-founded semantics but also two-valued as well as three-valued semantics for hybrid MKNF knowledge bases. Furthermore, we show an improved approximator for these knowledge bases, of which the least stable fixpoint is information richer than the one formulated from Knorr et al.'s construction. This leads to an improved computation for the well-founded semantics. This work is built on an extension of AFT that supports consistent as well as inconsistent pairs in the induced product bilattice, to deal with inconsistencies that arise in the context of hybrid MKNF knowledge bases. This part of the work can be considered generalizing the original AFT from symmetric approximators to arbitrary approximators.A study of interrelationships between rough set model accuracy and granule cover refinement processeshttps://zbmath.org/1530.682542024-04-15T15:10:58.286558Z"Yu, Zuoming"https://zbmath.org/authors/?q=ai:yu.zuoming"Wang, Dongqiang"https://zbmath.org/authors/?q=ai:wang.dongqiang"Wang, Pei"https://zbmath.org/authors/?q=ai:wang.pei.4Summary: Rough set model accuracy varies when granules change. Refinement is one way to characterize granule evolutions, but it has not been formally defined in rough set theory so far. Topologically, a granule cover \(\mathscr{W}\) is called a refinement of another granule cover \(\mathscr{F}\) if there exists some \(F_W\in\mathscr{F}\) such that \(W \subseteq F_W\) for each \(W\in\mathscr{W}\). In this article, we show that the concept refinement in topology is too abstract to describe the variability of the rough set model along with the change in granules. By abstracting from some important granule refinements, such as reductions and minimal descriptions, we propose two novel granule cover refinements named base-type refinements and base-preserving refinements, which combine both point-set topology and rough set theory. We analyze the accuracy relationships of some typical approximation operators between granule covers and their base-type or base-preserving refinements. We also show that higher accuracy implies finer granule covers for some approximation operators. These are promising results for rough set model accuracy comparisons. Furthermore, the results hint at how to avoid exponentially increased computation complexity on rough set model accuracy comparisons by checking refinement relationships of granule covers directly instead of computing on them using approximation operators.Fast reconfiguration of robot swarms with uniform control signalshttps://zbmath.org/1530.682552024-04-15T15:10:58.286558Z"Caballero, David"https://zbmath.org/authors/?q=ai:caballero.david"Cantu, Angel A."https://zbmath.org/authors/?q=ai:cantu.angel-a"Gomez, Timothy"https://zbmath.org/authors/?q=ai:gomez.timothy"Luchsinger, Austin"https://zbmath.org/authors/?q=ai:luchsinger.austin"Schweller, Robert"https://zbmath.org/authors/?q=ai:schweller.robert-t"Wylie, Tim"https://zbmath.org/authors/?q=ai:wylie.tim(no abstract)General deformations of point configurations viewed by a pinhole model camerahttps://zbmath.org/1530.682562024-04-15T15:10:58.286558Z"Kaminski, Yirmeyahu"https://zbmath.org/authors/?q=ai:kaminski.yirmeyahu-j"Werman, Michael"https://zbmath.org/authors/?q=ai:werman.michaelSummary: This paper is a theoretical study of the non-rigid structure from motion problem: what can be computed from a monocular view of a parametrically deforming set of points? We treat various variations of this problem for 3D affine and general smooth deformations (under some mild technical restrictions) with either a calibrated or an uncalibrated camera. We show that in general at least three images related by quasi-identical deformations are needed to have a finite set of solutions to the points' structure.Undecidability of a newly proposed calculus for CatLog3https://zbmath.org/1530.682572024-04-15T15:10:58.286558Z"Kanovich, Max"https://zbmath.org/authors/?q=ai:kanovich.max-i"Kuznetsov, Stepan"https://zbmath.org/authors/?q=ai:kuznetsov.s-l"Scedrov, Andre"https://zbmath.org/authors/?q=ai:scedrov.andreSummary: In his recent papers [J. Logic Lang. Inf. 28, No. 2, 183--216 (2019; Zbl 1478.68416); J. Lang. Model. 6, No. 2, 353--363 (2018; \url{doi:10.15398/jlm.v6i2.233})], \textit{G. Morrill} proposes a new substructural calculus to be used as the basis for the categorial grammar parser CatLog3. In this paper we prove that the derivability problem for a fragment of this calculus is algorithmically undecidable.
For the entire collection see [Zbl 1419.68004].An ASP-based approach to answering natural language questions for textshttps://zbmath.org/1530.682582024-04-15T15:10:58.286558Z"Pendharkar, Dhruva"https://zbmath.org/authors/?q=ai:pendharkar.dhruva"Basu, Kinjal"https://zbmath.org/authors/?q=ai:basu.kinjal"Shakerin, Farhad"https://zbmath.org/authors/?q=ai:shakerin.farhad"Gupta, Gopal"https://zbmath.org/authors/?q=ai:gupta.gopalSummary: An approach based on answer set programming (ASP) is proposed in this paper for representing knowledge generated from natural language texts. Knowledge in a text is modeled using a Neo Davidsonian-like formalism, which is then represented as an answer set program. Relevant commonsense knowledge is additionally imported from resources such as WordNet and represented in ASP. The resulting knowledge-base can then be used to perform reasoning with the help of an ASP system. This approach can facilitate many natural language tasks such as automated question answering, text summarization, and automated question generation. ASP-based representation of techniques such as default reasoning, hierarchical knowledge organization, preferences over defaults, etc., are used to model commonsense reasoning methods required to accomplish these tasks. In this paper, we describe the CASPR system that we have developed to automate the task of answering natural language questions given English text. CASPR can be regarded as a system that answers questions by ``understanding'' the text and has been tested on the SQuAD data set, with promising results.Dynamic time warping under translation: approximation guided by space-filling curveshttps://zbmath.org/1530.682592024-04-15T15:10:58.286558Z"Bringmann, Karl"https://zbmath.org/authors/?q=ai:bringmann.karl"Kisfaludi-Bak, Sándor"https://zbmath.org/authors/?q=ai:kisfaludi-bak.sandor"Künnemann, Marvin"https://zbmath.org/authors/?q=ai:kunnemann.marvin"Marx, Dániel"https://zbmath.org/authors/?q=ai:marx.daniel"Nusser, André"https://zbmath.org/authors/?q=ai:nusser.andreSummary: The Dynamic Time Warping (DTW) distance is a popular measure of similarity for a variety of sequence data. For comparing polygonal curves \(\pi\), \(\sigma\) in \(\mathbb{R}^d\), it provides a robust, outlier-insensitive alternative to the Fréchet distance. However, like the Fréchet distance, the DTW distance is not invariant under translations. Can we efficiently optimize the DTW distance of \(\pi\) and \(\sigma\) under arbitrary translations, to compare the curves' shape irrespective of their absolute location? There are surprisingly few works in this direction, which may be due to its computational intricacy: For the Euclidean norm, this problem contains as a special case the geometric median problem, which provably admits no exact algebraic algorithm (that is, no algorithm using only addition, multiplication, and \(k\)-th roots). We thus investigate exact algorithms for non-Euclidean norms as well as approximation algorithms for the Euclidean norm. \par For the \(L_1\) norm in \(\mathbb{R}^d\), we provide an \(\mathcal{O}(n^{2(d+1)})\)-time algorithm, i.e., an exact polynomial-time algorithm for constant \(d\). Here and below, \(n\) bounds the curves' complexities. For the Euclidean norm in \(\mathbb{R}^d\) with \(d\in\mathcal{O}(1)\), we show that a simple problem-specific insight leads to a \((1+\varepsilon)\)-approximation in time \(\mathcal{O}(n^3/\varepsilon^d)\). We then show how to obtain a subcubic \(\widetilde{\mathcal{O}}(n^{2.5}/\varepsilon^d)\) time algorithm with significant new ideas; this time comes close to the well-known quadratic time barrier for computing DTW for fixed translations. Technically, the algorithm is obtained by speeding up repeated DTW distance estimations using a dynamic data structure for maintaining shortest paths in weighted planar digraphs. Crucially, we show how to traverse a candidate set of translations using space-filling curves in a way that incurs only few updates to the data structure. We hope that our results facilitate the use of DTW under translation both in theory and practice, and inspire similar algorithmic approaches for related geometric optimization problems.Hop-spanners for geometric intersection graphshttps://zbmath.org/1530.682602024-04-15T15:10:58.286558Z"Conroy, Jonathan B."https://zbmath.org/authors/?q=ai:conroy.jonathan-b"Tóth, Csaba D."https://zbmath.org/authors/?q=ai:toth.csaba-dSummary: A \(t\)-spanner of a graph \(G=(V,E)\) is a subgraph \(H=(V,E')\) that contains a \(uv\)-path of length at most \(t\) for every \(uv\in E\). It is known that every \(n\)-vertex graph admits a \((2k-1)\)-spanner with \(O(n^{1+1/k})\) edges for \(k\ge 1\). This bound is the best possible for \(1\le k\le 9\) and is conjectured to be optimal due to Erdős' girth conjecture. \par We study \(t\)-spanners for \(t\in\{2,3\}\) for geometric intersection graphs in the plane. These spanners are also known as \(t\)-hop spannersto emphasize the use of graph-theoretic distances (as opposed to Euclidean distances between the geometric objects or their centers). We obtain the following results: (1) Every \(n\)-vertex unit disk graph (UDG) admits a 2-hop spanner with \(O(n)\) edges; improving upon the previous bound of \(O(n\log n)\). (2) The intersection graph of \(n\) axis-aligned fat rectangles admits a 2-hop spanner with \(O(n\log n)\) edges, and this bound is tight up to a factor of \(\log\log n\). (3) The intersection graph of \(n\) fat convex bodies in the plane admits a 3-hop spanner with \(O(n\log n)\) edges. (4) The intersection graph of \(n\) axis-aligned rectangles admits a 3-hop spanner with \(O(n\log^2n)\) edges.Minimum rectilinear polygons for given angle sequenceshttps://zbmath.org/1530.682612024-04-15T15:10:58.286558Z"Evans, William S."https://zbmath.org/authors/?q=ai:evans.william-s"Fleszar, Krzysztof"https://zbmath.org/authors/?q=ai:fleszar.krzysztof"Kindermann, Philipp"https://zbmath.org/authors/?q=ai:kindermann.philipp"Saeedi, Noushin"https://zbmath.org/authors/?q=ai:saeedi.noushin"Shin, Chan-Su"https://zbmath.org/authors/?q=ai:shin.chan-su"Wolff, Alexander"https://zbmath.org/authors/?q=ai:wolff.alexanderSummary: A \textit{rectilinear} polygon is a simple polygon whose edges are axis-aligned. Walking counterclockwise on the boundary of such a polygon yields a sequence of left turns and right turns. The number of left turns always equals the number of right turns plus four. It is known that any such sequence can be realized by a rectilinear polygon.
In this paper, we consider the problem of finding realizations that minimize the perimeter or the area of the polygon or the area of the bounding box of the polygon. We show that all three problems are \(\mathsf{NP} \)-hard in general. This answers an open question of \textit{M. Patrignani} [Comput. Geom. 19, No. 1, 47--67 (2001; Zbl 0990.68169)], who showed that it is \(\mathsf{NP} \)-hard to minimize the area of the bounding box of an orthogonal drawing of a given planar graph. We also show that realizing a polyline within a bounding box of minimum area (or within a fixed given rectangle) is \(\mathsf{NP} \)-hard. Then we consider the special cases of \(x\)-monotone and \(xy\)-monotone rectilinear polygons. For these, we can optimize the three objectives efficiently.Moment evolution equations and moment matching for stochastic image EPDiffhttps://zbmath.org/1530.682622024-04-15T15:10:58.286558Z"Christgau, Alexander Mangulad"https://zbmath.org/authors/?q=ai:christgau.alexander-mangulad"Arnaudon, Alexis"https://zbmath.org/authors/?q=ai:arnaudon.alexis"Sommer, Stefan"https://zbmath.org/authors/?q=ai:sommer.stefanSummary: Models of stochastic image deformation allow study of time-continuous stochastic effects transforming images by deforming the image domain. Applications include longitudinal medical image analysis with both population trends and random subject-specific variation. Focusing on a stochastic extension of the LDDMM models with evolutions governed by a stochastic EPDiff equation, we use moment approximations of the corresponding Itô diffusion to construct estimators for statistical inference in the full stochastic model. We show that this approach, when efficiently implemented with automatic differentiation tools, can successfully estimate parameters encoding the spatial correlation of the noise fields on the image.Multi-component separation, inpainting and denoising with recovery guaranteeshttps://zbmath.org/1530.682632024-04-15T15:10:58.286558Z"Do, Van Tiep"https://zbmath.org/authors/?q=ai:do.van-tiepSummary: In image processing, problems of separation and reconstruction of missing pixels from incomplete digital images have been far more advanced in past decades. Many empirical results have produced very good results; however, providing a theoretical analysis for the success of algorithms is not an easy task, especially, for inpainting and separating multi-component signals. In this paper, we propose two main algorithms based on \(l_1\) constrained and unconstrained minimization for separating \(N\) distinct geometric components and simultaneously filling in the missing part of the observed image. We then present a theoretical guarantee for these algorithms using compressed sensing technique, which is based on a principle that each component can be sparsely represented by a suitably chosen dictionary. Those sparsifying systems are extended to the case of general frames instead of Parseval frames which have been typically used in the past. We finally prove that the method does indeed succeed in separating point singularities from curvilinear singularities and texture as well as inpainting the missing band contained in curvilinear singularities and texture.IFF: a superresolution algorithm for multiple measurementshttps://zbmath.org/1530.682642024-04-15T15:10:58.286558Z"Fei, Zetao"https://zbmath.org/authors/?q=ai:fei.zetao"Zhang, Hai"https://zbmath.org/authors/?q=ai:zhang.hai.2|zhang.hai.1|zhang.hai.4|zhang.hai.3|zhang.haiSummary: We consider the problem of reconstructing one-dimensional point sources from their Fourier measurements in a bounded interval \([-\Omega, \Omega]\). This problem is known to be challenging in the regime where the spacing of the sources is below the Rayleigh length \(\frac{\pi}{\Omega} \). In this paper, we propose a superresolution algorithm, called iterative focusing-localization and iltering, to resolve closely spaced point sources from their multiple measurements that are obtained by using multiple unknown illumination patterns. The new proposed algorithm has a distinct feature in that it reconstructs the point sources one by one in an iterative manner and hence requires no prior information about the source numbers. The new feature also allows for a subsampling strategy that can reconstruct sources using small-sized Hankel matrices and thus circumvent the computation of singular-value decomposition for large matrices as in the usual subspace methods. In addition, the algorithm can be paralleled. A theoretical analysis of the methods behind the algorithm is also provided. The derived results imply a phase transition phenomenon in the reconstruction of source locations which is confirmed in the numerical experiment. Numerical results show that the algorithm can achieve a stable reconstruction for point sources with a minimum separation distance that is close to the theoretical limit. The efficiency and robustness of the algorithm have also been tested. This algorithm can be generalized to higher dimensions.The 2-orthogonal and orthogonal radial shape moments for image representation and recognitionhttps://zbmath.org/1530.682652024-04-15T15:10:58.286558Z"Hjouji, Amal"https://zbmath.org/authors/?q=ai:hjouji.amal"EL-Mekkaoui, Jaouad"https://zbmath.org/authors/?q=ai:el-mekkaoui.jaouadImage recognition typically requires an extraction technique for feature vectors of the images studied. At the same time it is known that these vectors should be invariant to the three following geometric transformations: rotation, translation and scaling. Because of this, the theory of orthogonal moments are important tools in many pattern recognition applications. In this interesting paper, the authors generalize several notions of orthogonality and orthogonal moments by introducing two ideas they call: (a) ``\textit{\textbf {p-orthogonality}}'' and (b) ``\textit{\textbf{p-orthogonal moments}}''. They show that a $p$-orthogonal set of functions is composed of $p$ orthogonal subsets. They prove that the set of linear shape functions or hat functions, used in the finite element method (FEM), is also \textit{2-orthogonal}. Using these functions, the authors present four types of moments: (a) the set of 2-orthogonal radial shape moments \((_2\mathrm{ORSMs})\), (b) the set of orthogonal radial shape moments \((_1\mathrm{ORSMs})\) for gray-level images, (c) the set of multi-channel 2-orthogonal radial shape moments \(_2\mathrm{MRSMs})\) and (d) the set of multi-channel orthogonal radial shape moments \((_1\mathrm{MRSMs})\) for color images. Invariants to translation, scaling and rotation (TSR) of the four proposed moments are derived for image representation and recognition. The authors present a set of numerical experiments to evaluate the performance of the proposed invariant moments.Properties of morphological dilation in max-plus and plus-prod algebra in connection with the Fourier transformationhttps://zbmath.org/1530.682662024-04-15T15:10:58.286558Z"Kahra, Marvin"https://zbmath.org/authors/?q=ai:kahra.marvin"Breuß, Michael"https://zbmath.org/authors/?q=ai:breuss.michaelSummary: The basic filters in mathematical morphology are dilation and erosion. They are defined by a structuring element that is usually shifted pixel-wise over an image, together with a comparison process that takes place within the corresponding mask. This comparison is made in the grey value case by means of maximum or minimum formation. Hence, there is easy access to max-plus algebra and, by means of an algebra change, also to the theory of linear algebra. We show that an approximation of the maximum function forms a commutative semifield (with respect to multiplication) and corresponds to the maximum again in the limit case. In this way, we demonstrate a novel access to the logarithmic connection between the Fourier transform and the slope transformation. In addition, we prove that the dilation by means of a fast Fourier transform depends only on the size of the structuring element used. Moreover, we derive a bound above which the Fourier approximation yields results that are exact in terms of grey value quantisation.Local binary patterns of segments of a binary object for shape analysishttps://zbmath.org/1530.682672024-04-15T15:10:58.286558Z"Kumar, Ratnesh"https://zbmath.org/authors/?q=ai:kumar.ratnesh-r|kumar.ratnesh"Mali, Kalyani"https://zbmath.org/authors/?q=ai:mali.kalyaniSummary: The paper presents an effective, robust and geometrically invariants, collection of contours or boundaries base local binary pattern (LBP) for binary object shape retrieval and classification. The contours segmentation or deformations of an object is a preprocessing step of shape retrieval and classification that segment the binary object shape in a shape-preserving sequence of contours segment using a coordination number shape segmentation approach. The proposed local binary pattern extracts the minimum decimal value corresponding to the pattern of object contour points for each and every contours segment. It is one of the most important features in content-based image retrieval. At the matching stage, we find Euclidean distance between eigenvalues of correlation coefficient of Hu's seven moments corresponding to each contour segment for given two objects. The LBP pattern corresponding to the image contour provides excellent power, which is demonstrated by excellent retrieval performance on several popular shape benchmarks, including MPEG-7 CE-Shape-1 dataset and Kimia's dataset. Experimental results obtained from popular databases demonstrate that the proposed linear binary pattern can achieve comparably better results than existing algorithms.A physically admissible Stokes vector reconstruction in linear polarimetric imaginghttps://zbmath.org/1530.682682024-04-15T15:10:58.286558Z"Le Guyader, Carole"https://zbmath.org/authors/?q=ai:le-guyader.carole"Ainouz, Samia"https://zbmath.org/authors/?q=ai:ainouz.samia"Canu, Stéphane"https://zbmath.org/authors/?q=ai:canu.stephaneSummary: Polarization encoded images improve on conventional intensity imaging techniques by providing access to additional parameters describing the vector nature of light. In a polarimetric image, each pixel is related to a \(4 \times 1\) vector named Stokes vector (\(3 \times 1\) in a linear configuration, which is the framework retained afterwards). Such images comprise a valuable set of physical information on the objects they contain, amplifying subsequently the accuracy of the analysis that can be done. A Stokes imaging polarimeter yields data named radiance images from which Stokes vectors are reconstructed, supposed to comply with a physical admissibility constraint. Classical estimation techniques such as pseudo-inverse approach exhibit defects, hampering any relevant physical interpretation of the scene: (i) first, due to their sensitivity to noise and errors that may contaminate the observed radiance images and that may then propagate to the evaluation of the Stokes vector components, thus justifying an ad hoc a posteriori treatment of Stokes vectors; (ii) second, in not taking this physical admissibility criterion explicitly into account. Motivated by this observation, the proposed contribution aims to provide a method of reconstruction addressing both issues, thus ensuring smoothness and spatial consistency of the reconstructed components, as well as compliance with the prescribed physical admissibility constraint. A by-product of the algorithm is that the resulting angle of polarization reflects more faithfully the physical properties of the materials present in the image. The mathematical formulation yields a non-smooth convex optimization problem that is then converted into a min-max problem and solved by the generic Chambolle-Pock primal-dual algorithm. Several mathematical results (such as existence/uniqueness of the minimizer of the primal problem, existence of a saddle point to the associated Lagrangian, etc.) are supplied and highlight the well-posed character of the modelling. Experiments demonstrate that our method provides significant improvements (i) over the least square-based method both in terms of quantitative criteria (physical admissibility constraint automatically met) and qualitative assessment (spatial regularization/coherency), (ii) over the physical consistency of related relevant polarimetric parameters such as the angle and degree of polarization, (iii) robustness of the method when applied on real outdoor scenes acquired in degraded conditions (poor weather conditions, etc.).Self-supervised deep learning for image reconstruction: a Langevin Monte Carlo approachhttps://zbmath.org/1530.682692024-04-15T15:10:58.286558Z"Li, Ji"https://zbmath.org/authors/?q=ai:li.ji"Wang, Weixi"https://zbmath.org/authors/?q=ai:wang.weixi"Ji, Hui"https://zbmath.org/authors/?q=ai:ji.huiSummary: Deep learning has proved to be a powerful tool for solving inverse problems in imaging, and most of the related work is based on supervised learning. In many applications, collecting truth images is a challenging and costly task, and the prerequisite of having a training dataset of truth images limits its applicability. This paper proposes a self-supervised deep learning method for solving inverse imaging problems that does not require any training samples. The proposed approach is built on a reparametrization of latent images using a convolutional neural network, and the reconstruction is motivated by approximating the minimum mean square error estimate of the latent image using a Langevin dynamics-based Monte Carlo (MC) method. To efficiently sample the network weights in the context of image reconstruction, we propose a Langevin MC scheme called Adam-LD, inspired by the well-known optimizer in deep learning, Adam. The proposed method is applied to solve linear and nonlinear inverse problems, specifically, sparse-view computed tomography image reconstruction and phase retrieval. Our experiments demonstrate that the proposed method outperforms existing unsupervised or self-supervised solutions in terms of reconstruction quality.On extensibility of proof checkershttps://zbmath.org/1530.682702024-04-15T15:10:58.286558Z"Pollack, Robert"https://zbmath.org/authors/?q=ai:pollack.robert.1|pollack.robert.2Summary: My suggestion is little different from LCF, just replacing one computational meta language (ML) with another (ECC, FS\textsubscript{0}, \dots). The philosophical point is that it is then possible to accept non canonical proof notations as object level proofs, removing the need to actually normalize them. There are problems to be worked out in practice, such as extraction of programs from constructive proof, and efficient execution of pure, total programs. Although this approach doesn't address the difficulty of proving correctness of tactics in the meta level, it is immediatly useful for tactics with structural justification (e.g. weakening) which are not even representable in LCF, and are infeasible in the Nuprl variant of LCF. Since it can be used for any object system without adding new principles such as reflection, and is compatible with other approaches to extensibility (especially partial reflection), it should be considered as part of the answer to extensibility in proof checkers.
For the entire collection see [Zbl 0866.00037].A REST API for zbMATH Open accesshttps://zbmath.org/1530.682712024-04-15T15:10:58.286558Z"Fuhrmann, Marcel"https://zbmath.org/authors/?q=ai:fuhrmann.marcel"Müller, Fabian"https://zbmath.org/authors/?q=ai:muller.fabian.1|muller.fabian-l|muller.fabian(no abstract)A program to create new geometry proof problemshttps://zbmath.org/1530.682722024-04-15T15:10:58.286558Z"Todd, Philip"https://zbmath.org/authors/?q=ai:todd.philip-h"Aley, Danny"https://zbmath.org/authors/?q=ai:aley.dannySummary: In a previous paper [Zbl 1530.15025], linear systems corresponding to sets of angle bisector conditions are analyzed. In a system which is not full rank, one bisector condition can be derived from the others. In that paper, we describe methods for finding such rank deficient linear systems. The vector angle bisector relationship may be interpreted geometrically in a number of ways: as an angle bisector, as a reflection, as an isosceles triangle, or as a circle chord. A rank deficient linear system may be interpreted as a geometry theorem by mapping each vector angle bisector relationship onto one of these geometrical representations. In Todd (Submitted to AMAI, 2022) we illustrate the step from linear system to geometry theorem with a number of by-hand constructed examples. In this paper, we present an algorithm which automatically generates a geometry theorem from a starting point of a linear system of the type identified in [loc. cit.]. Both statement and diagram of the new theorem are generated by the algorithm. Our implementation creates a simple text description of the new theorem and utilizes the Mathematica GeometricScene to form a diagram.Classical and quantum algorithms for constructing text from dictionary problemhttps://zbmath.org/1530.682732024-04-15T15:10:58.286558Z"Khadiev, Kamil"https://zbmath.org/authors/?q=ai:khadiev.kamil"Remidovskii, Vladislav"https://zbmath.org/authors/?q=ai:remidovskii.vladislav(no abstract)A binary monkey search algorithm variation for solving the set covering problemhttps://zbmath.org/1530.682742024-04-15T15:10:58.286558Z"Crawford, Broderick"https://zbmath.org/authors/?q=ai:crawford.broderick"Soto, Ricardo"https://zbmath.org/authors/?q=ai:soto.ricardo-lorenzo"Olivares, Rodrigo"https://zbmath.org/authors/?q=ai:olivares.rodrigo"Embry, Gabriel"https://zbmath.org/authors/?q=ai:embry.gabriel"Flores, Diego"https://zbmath.org/authors/?q=ai:flores.diego"Palma, Wenceslao"https://zbmath.org/authors/?q=ai:palma.wenceslao"Castro, Carlos"https://zbmath.org/authors/?q=ai:castro.carlos.1"Paredes, Fernando"https://zbmath.org/authors/?q=ai:paredes.fernando"Rubio, José-Miguel"https://zbmath.org/authors/?q=ai:rubio.jose-miguel(no abstract)Similarity in metaheuristics: a gentle step towards a comparison methodologyhttps://zbmath.org/1530.682752024-04-15T15:10:58.286558Z"de Armas, Jesica"https://zbmath.org/authors/?q=ai:de-armas.jesica"Lalla-Ruiz, Eduardo"https://zbmath.org/authors/?q=ai:lalla-ruiz.eduardo"Tilahun, Surafel Luleseged"https://zbmath.org/authors/?q=ai:tilahun.surafel-luleseged"Voß, Stefan"https://zbmath.org/authors/?q=ai:voss.stefanSummary: Metaheuristics are found to be efficient in different applications where the use of exact algorithms becomes short-handed. In the last decade, many of these algorithms have been introduced and used in a wide range of applications. Nevertheless, most of those approaches share similar components leading to a concern related to their novelty or contribution. Thus, in this paper, a pool template is proposed and used to categorize algorithm components permitting to analyze them in a structured way. We exemplify its use by means of continuous optimization metaheuristics, and provide some measures and methodology to identify their similarities and novelties. Finally, a discussion at a component level is provided in order to point out possible design differences and commonalities.On the class of hybrid adaptive evolutionary algorithms (\textsc{chavela})https://zbmath.org/1530.682762024-04-15T15:10:58.286558Z"Gómez, Jonatan"https://zbmath.org/authors/?q=ai:gomez.jonatan"León, Elizabeth"https://zbmath.org/authors/?q=ai:leon.elizabethSummary: There is no doubt that both determining theoretical properties and characterizing the observed behavior of an evolutionary algorithm allow us to understand when to use such an algorithm in solving a class of optimization problems. One of those evolutionary algorithms is the Hybrid Adaptive Evolutionary Algorithm (\textsc{haea}). The general scheme followed by a \textsc{haea} algorithm is to evolve every individual of the population by selecting genetic operators according to a kind of chaotic competition mechanism. This paper proposes and studies, from both theoretical and experimental points of view, the class of hybrid adaptive evolutionary algorithms (called \textsc{chavela}), i.e., the class of evolutionary algorithms that follow such a general scheme. In this way, this paper presents a formal characterization of the \textsc{chavela} class in terms of Markov kernels; establishes convergence properties; proves that (parallel) hill-climbing algorithms belong to the \textsc{chavela} class; develops generational, steady-state, and classic versions; and analyzes the running behavior of \textsc{chavela} on well-known optimization functions.Benchmarking the performance of genetic algorithms on constrained dynamic problemshttps://zbmath.org/1530.682772024-04-15T15:10:58.286558Z"Grudniewski, P. A."https://zbmath.org/authors/?q=ai:grudniewski.p-a"Sobey, A. J."https://zbmath.org/authors/?q=ai:sobey.a-j(no abstract)Cultural particle swarm optimization algorithms for uncertain multi-objective problems with interval parametershttps://zbmath.org/1530.682782024-04-15T15:10:58.286558Z"Guo, Yi-nan"https://zbmath.org/authors/?q=ai:guo.yinan"Yang, Zhen"https://zbmath.org/authors/?q=ai:yang.zhen"Wang, Chun"https://zbmath.org/authors/?q=ai:wang.chun.3"Gong, Dunwei"https://zbmath.org/authors/?q=ai:gong.dunwei(no abstract)Memetic electromagnetism algorithm for surface reconstruction with rational bivariate Bernstein basis functionshttps://zbmath.org/1530.682792024-04-15T15:10:58.286558Z"Iglesias, Andrés"https://zbmath.org/authors/?q=ai:iglesias.andres"Gálvez, Akemi"https://zbmath.org/authors/?q=ai:galvez.akemi(no abstract)Absolute versus stochastic stability of the artificial bee colony in synchronous and sequential modeshttps://zbmath.org/1530.682802024-04-15T15:10:58.286558Z"Kessentini, Sameh"https://zbmath.org/authors/?q=ai:kessentini.sameh"Naâs, Ihcène"https://zbmath.org/authors/?q=ai:naas.ihcene(no abstract)Quantum ant colony optimization algorithm for AGVs path planning based on Bloch coordinates of pheromoneshttps://zbmath.org/1530.682812024-04-15T15:10:58.286558Z"Li, Junjun"https://zbmath.org/authors/?q=ai:li.junjun"Xu, Bowei"https://zbmath.org/authors/?q=ai:xu.bowei"Yang, Yongsheng"https://zbmath.org/authors/?q=ai:yang.yongsheng"Wu, Huafeng"https://zbmath.org/authors/?q=ai:wu.huafeng(no abstract)Exact Markov chain-based runtime analysis of a discrete particle swarm optimization algorithm on sorting and OneMaxhttps://zbmath.org/1530.682822024-04-15T15:10:58.286558Z"Mühlenthaler, Moritz"https://zbmath.org/authors/?q=ai:muhlenthaler.moritz"Raß, Alexander"https://zbmath.org/authors/?q=ai:rass.alexander"Schmitt, Manuel"https://zbmath.org/authors/?q=ai:schmitt.manuel"Wanka, Rolf"https://zbmath.org/authors/?q=ai:wanka.rolfSummary: Meta-heuristics are powerful tools for solving optimization problems whose structural properties are unknown or cannot be exploited algorithmically. We propose such a meta-heuristic for a large class of optimization problems over discrete domains based on the \textit{particle swarm optimization} (PSO) paradigm. We provide a comprehensive formal analysis of the performance of this algorithm on certain ``easy'' reference problems in a black-box setting, namely the sorting problem and the problem OneMax. In our analysis we use a Markov model of the proposed algorithm to obtain upper and lower bounds on its expected optimization time. Our bounds are essentially tight with respect to the Markov model. We show that for a suitable choice of algorithm parameters the expected optimization time is comparable to that of known algorithms and, furthermore, for other parameter regimes, the algorithm behaves less greedy and more explorative, which can be desirable in practice in order to escape local optima. Our analysis provides a precise insight on the tradeoff between optimization time and exploration. To obtain our results we introduce the notion of \textit{indistinguishability} of states of a Markov chain and provide bounds on the solution of a recurrence equation with non-constant coefficients by integration.Evolutionary algorithms and submodular functions: benefits of heavy-tailed mutationshttps://zbmath.org/1530.682832024-04-15T15:10:58.286558Z"Quinzan, Francesco"https://zbmath.org/authors/?q=ai:quinzan.francesco"Göbel, Andreas"https://zbmath.org/authors/?q=ai:gobel.andreas-nikolas"Wagner, Markus"https://zbmath.org/authors/?q=ai:wagner.markus"Friedrich, Tobias"https://zbmath.org/authors/?q=ai:friedrich.tobias(no abstract)Meta-heuristic approaches to solve shortest lattice vector problemhttps://zbmath.org/1530.682842024-04-15T15:10:58.286558Z"Reddy, V. Dinesh"https://zbmath.org/authors/?q=ai:reddy.v-dinesh"Rao, G. S. V. R. K."https://zbmath.org/authors/?q=ai:rao.g-s-v-r-kSummary: We present the aptness of population based meta-heuristic approaches to compute a shortest non-zero vector in a lattice for solving the Shortest lattice Vector Problem (SVP). This problem has a great many applications such as optimization, communication theory, cryptography, etc. At the same time, SVP is notoriously hard to predict, both in terms of running time and output quality.
The SVP is known to be NP-hard under randomized reduction and there is no polynomial time solution for this problem. Though LLL algorithm is a polynomial time algorithm, it does not give the optimal solutions. In this paper, we present the application of Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) to solve the SVP on an appropriate search space. We have implemented the PSO, GA and LLL algorithm for the SVP. The comparison results shows that our algorithm works for all instances.On sampling error in genetic programminghttps://zbmath.org/1530.682852024-04-15T15:10:58.286558Z"Schweim, Dirk"https://zbmath.org/authors/?q=ai:schweim.dirk"Wittenberg, David"https://zbmath.org/authors/?q=ai:wittenberg.david-k"Rothlauf, Franz"https://zbmath.org/authors/?q=ai:rothlauf.franz(no abstract)Self-configuring nature inspired algorithms for combinatorial optimization problemshttps://zbmath.org/1530.682862024-04-15T15:10:58.286558Z"Semenkina, Olga Ev."https://zbmath.org/authors/?q=ai:semenkina.olga-ev"Popov, Eugene A."https://zbmath.org/authors/?q=ai:popov.eugene-a"Semenkina, Olga Er."https://zbmath.org/authors/?q=ai:semenkina.olga-erSummary: In this work authors introduce and study the self-configuring Genetic Algorithm (GA) and the self-configuring Ant Colony Optimization (ACO) algorithm and apply them to one of the most known combinatorial optimization task -- Travelling Salesman Problem (TSP). The estimation of suggested algorithms performance is fulfilled on well-known benchmark TSP and then compared with other heuristics such as Lin-Kernigan (3-opt local search) and Intelligent Water Drops algorithm (IWDs). Numerical experiments show that suggested approach demonstrates the competitive performance. Both adaptive algorithms show good results on these problems as they outperform other algorithms with their settings with average performance.A survey on traffic optimization problem using biologically inspired techniqueshttps://zbmath.org/1530.682872024-04-15T15:10:58.286558Z"Srivastava, Sweta"https://zbmath.org/authors/?q=ai:srivastava.sweta"Sahana, Sudip Kumar"https://zbmath.org/authors/?q=ai:sahana.sudip-kumar(no abstract)Hybrid ant colony optimization algorithm applied to the multi-depot vehicle routing problemhttps://zbmath.org/1530.682882024-04-15T15:10:58.286558Z"Stodola, Petr"https://zbmath.org/authors/?q=ai:stodola.petr(no abstract)Perturbations and phase transitions in swarm optimization algorithmshttps://zbmath.org/1530.682892024-04-15T15:10:58.286558Z"Vantuch, Tomáš"https://zbmath.org/authors/?q=ai:vantuch.tomas"Zelinka, Ivan"https://zbmath.org/authors/?q=ai:zelinka.ivan"Adamatzky, Andrew"https://zbmath.org/authors/?q=ai:adamatzky.andrew-i"Marwan, Norbert"https://zbmath.org/authors/?q=ai:marwan.norbert(no abstract)Particle swarm optimization based on temporal-difference learning for solving multi-objective optimization problemshttps://zbmath.org/1530.682902024-04-15T15:10:58.286558Z"Zhang, Desong"https://zbmath.org/authors/?q=ai:zhang.desong"Zhu, Guangyu"https://zbmath.org/authors/?q=ai:zhu.guangyu(no abstract)A self-adaptive multi-population differential evolution algorithmhttps://zbmath.org/1530.682912024-04-15T15:10:58.286558Z"Zhu, Lin"https://zbmath.org/authors/?q=ai:zhu.lin"Ma, Yongjie"https://zbmath.org/authors/?q=ai:ma.yongjie"Bai, Yulong"https://zbmath.org/authors/?q=ai:bai.yulong(no abstract)Adaptive multimeme algorithm for flexible job shop scheduling problemhttps://zbmath.org/1530.682922024-04-15T15:10:58.286558Z"Zuo, Yi"https://zbmath.org/authors/?q=ai:zuo.yi"Gong, Maoguo"https://zbmath.org/authors/?q=ai:gong.maoguo"Jiao, Licheng"https://zbmath.org/authors/?q=ai:jiao.licheng(no abstract)Neural-network-based fluid-structure interaction applied to vortex-induced vibrationhttps://zbmath.org/1530.700022024-04-15T15:10:58.286558Z"Bublík, Ondřej"https://zbmath.org/authors/?q=ai:bublik.ondrej"Heidler, Václav"https://zbmath.org/authors/?q=ai:heidler.vaclav"Pecka, Aleš"https://zbmath.org/authors/?q=ai:pecka.ales"Vimmr, Jan"https://zbmath.org/authors/?q=ai:vimmr.janSummary: In this paper, a fluid-structure interaction (FSI) solver with neural-network-based fluid-flow prediction is proposed. This concept is applied to the problem of vortex-induced vibration of a cylinder. The majority of studies that are concerned with fluid-flow prediction using neural networks solve problems with fixed boundary. In this paper, a convolutional neural network (CNN) is used to predict unsteady incompressible laminar flow with moving boundary. A deformable non-Cartesian grid, which traces the boundary of the fluid domain, is used in this paper. The CNN is trained for oscillating cylinder with various frequencies and amplitudes. The dynamics of the elastically-mounted cylinder is modelled using a linear spring-mass-damper model and solved by an implicit differential scheme. The results show that the CNN-based FSI solver is capable of capturing the so-called lock-in phenomenon for the problem of vortex-induced vibration of a cylinder and the quantitative behaviour is similar to the results of the CFD-based FSI solver. Moreover, the CNN-based FSI solver is two orders of magnitude faster than the CFD-based FSI solver and the speedup is expected to be even greater on larger problems.On equilibrium positions in the problem of the motion of a system of two bodies in a uniform gravity fieldhttps://zbmath.org/1530.700102024-04-15T15:10:58.286558Z"Irtegov, Valentin"https://zbmath.org/authors/?q=ai:irtegov.valentin-dmitrievich"Titorenko, Tatiana"https://zbmath.org/authors/?q=ai:titorenko.tatiana-nSummary: In the problem of motion of a system of two rigid bodies connected by a spherical hinge in a uniform gravity field, the conditions for the existence of two- and one-dimensional invariant manifolds are presented, and the manifolds themselves are found with the use of computer algebra tools. From a mechanical point of view, these solutions correspond to equilibrium positions of the system. Their instability in the first approximation is proved.
For the entire collection see [Zbl 1507.68024].A computational framework for nanotrusses: input convex neural networks approachhttps://zbmath.org/1530.740522024-04-15T15:10:58.286558Z"Čanađija, Marko"https://zbmath.org/authors/?q=ai:canadija.marko"Košmerl, Valentina"https://zbmath.org/authors/?q=ai:kosmerl.valentina"Zlatić, Martin"https://zbmath.org/authors/?q=ai:zlatic.martin"Vrtovšnik, Domagoj"https://zbmath.org/authors/?q=ai:vrtovsnik.domagoj"Munjas, Neven"https://zbmath.org/authors/?q=ai:munjas.nevenSummary: The present research aims to provide a practical numerical tool for the mechanical analysis of nanoscale trusses with similar accuracy to molecular dynamics (MD). As a first step, MD simulations of uniaxial tensile and compression tests of all possible chiralities of single-walled carbon nanotubes up to 4 nm in diameter were performed using the AIREBO potential. The results represent a dataset consisting of stress/strain curves that were then used to develop a neural network that serves as a surrogate for a constitutive model for all nanotubes considered. The cornerstone of the new framework is a partially input convex integrable neural network. It turns out that convexity enables favorable convergence properties required for implementation in the classical nonlinear truss finite element available in Abaqus. This completes a molecular dynamics-machine learning-finite element framework suitable for the static analysis of large, nanoscale, truss-like structures. The performance is verified through a comprehensive set of examples that demonstrate ease of use, accuracy, and robustness.A machine learning approach to automate ductile damage parameter selection using finite element simulationshttps://zbmath.org/1530.740732024-04-15T15:10:58.286558Z"O'Connor, A. N."https://zbmath.org/authors/?q=ai:oconnor.a-n"Mongan, P. G."https://zbmath.org/authors/?q=ai:mongan.p-g"O'Dowd, N. P."https://zbmath.org/authors/?q=ai:odowd.noel-pSummary: Ductile damage models require constitutive model parameter values that are difficult to derive experimentally or analytically. The calibration procedure for ductile damage model parameters, typically performed manually, is labour-intensive. In this work we detail a fully autonomous framework that integrates Bayesian optimisation and finite element analysis to identify ductile damage model parameters. The framework detailed here selects ductile damage model parameters from inputs that can be derived from a simple tensile test. This framework has been successfully deployed to three datasets of P91 material tested at ambient (20 {\celsius}) and higher (500 {\celsius}) temperatures. The Bayesian optimisation derived material model parameters result in simulated output with less than 2\% error compared to experimental data. This research demonstrates that algorithm hyperparameters can significantly affect the Bayesian optimised ductile damage parameter values resulting in non-unique ductile damage parameters. We show that the non-unique solutions can be further assessed using a second test geometry.Towards real-time fluid dynamics simulation: a data-driven NN-MPS method and its implementationhttps://zbmath.org/1530.760542024-04-15T15:10:58.286558Z"Yao, Qinghe"https://zbmath.org/authors/?q=ai:yao.qinghe"Wang, Zhuolin"https://zbmath.org/authors/?q=ai:wang.zhuolin"Zhang, Yi"https://zbmath.org/authors/?q=ai:zhang.yi.14|zhang.yi.3|yi.zhang|zhang.yi.12|zhang.yi.2|zhang.yi.48|zhang.yi.17|zhang.yi.5|zhang.yi.1|zhang.yi.18|zhang.yi.8|zhang.yi.4|zhang.yi.10|zhang.yi.6|zhang.yi"Li, Zijie"https://zbmath.org/authors/?q=ai:li.zijie"Jiang, Junyang"https://zbmath.org/authors/?q=ai:jiang.junyangSummary: In this work, we construct a data-driven model to address the computing performance problem of the moving particle semi-implicit method by combining the physics intuition of the method with a machine-learning algorithm. A fully connected artificial neural network is implemented to solve the pressure Poisson equation, which is reformulated as a regression problem. We design context-based feature vectors for particle-based on the Poisson equation. The neural network maintains the original particle method's accuracy and stability, while drastically accelerates the pressure calculation. It is very suitable for GPU parallelization, edge computing scenarios and real-time simulations.A data-driven method for modelling dissipation rates in stratified turbulencehttps://zbmath.org/1530.760582024-04-15T15:10:58.286558Z"Lewin, Samuel F."https://zbmath.org/authors/?q=ai:lewin.samuel-f"de Bruyn Kops, Stephen M."https://zbmath.org/authors/?q=ai:de-bruyn-kops.stephen-m"Caulfield, Colm-Cille P."https://zbmath.org/authors/?q=ai:caulfield.colm-cille-p"Portwood, Gavin D."https://zbmath.org/authors/?q=ai:portwood.gavin-dSummary: We present a deep probabilistic convolutional neural network (PCNN) model for predicting local values of small-scale mixing properties in stratified turbulent flows, namely the dissipation rates of turbulent kinetic energy and density variance, \(\varepsilon\) and \(\chi\). Inputs to the PCNN are vertical columns of velocity and density gradients, motivated by data typically available from microstructure profilers in the ocean. The architecture is designed to enable the model to capture several characteristic features of stratified turbulence, in particular the dependence of small-scale isotropy on the buoyancy Reynolds number \(Re_b := \varepsilon/(\nu N^2)\), where \(\nu\) is the kinematic viscosity and \(N\) is the background buoyancy frequency, the correlation between suitably locally averaged density gradients and turbulence intensity and the importance of capturing the tails of the probability distribution functions of values of dissipation. Empirically modified versions of commonly used isotropic models for \(\varepsilon\) and \(\chi\) that depend only on vertical derivatives of density and velocity are proposed based on the asymptotic regimes \(Re_b\ll 1\) and \(Re_b\gg 1\), and serve as an instructive benchmark for comparison with the data-driven approach. When trained and tested on a simulation of stratified decaying turbulence which accesses a range of turbulent regimes (associated with differing values of \(Re_b\)), the PCNN outperforms assumptions of isotropy significantly as \(Re_b\) decreases, and additionally demonstrates improvements over the fitted empirical models. A differential sensitivity analysis of the PCNN facilitates a comparison with the theoretical models and provides a physical interpretation of the features enabling it to make improved predictions.Intelligent Bayesian regularization-based solution predictive procedure for hybrid nanoparticles of AA7072-AA7075 oxide movement across a porous mediumhttps://zbmath.org/1530.760792024-04-15T15:10:58.286558Z"Awan, Saeed Ehsan"https://zbmath.org/authors/?q=ai:awan.saeed-ehsan"Ali, Faizan"https://zbmath.org/authors/?q=ai:ali.faizan"Awais, Muhammad"https://zbmath.org/authors/?q=ai:awais.muhammad"Shoaib, Muhammad"https://zbmath.org/authors/?q=ai:shoaib.muhammad"Raja, Muhammad Asif Zahoor"https://zbmath.org/authors/?q=ai:raja.muhammad-asif-zahoorSummary: The research community has shown great interest for investigation in the nanofluids models involving Aluminum Alloys AA7072 and AA7072+AA7075 due to their advantageous impact on heat transfer, physical and mechanical characteristic exploiting in broad engineering applications such as manufacturing of spacecraft, aircraft parts and building testing. The hybrid nanomaterial AA7072-AA7075 based fluidic system is investigated in this paper using an artificial neural network with Bayesian regularization scheme (ANNs-BRS). The derived partial differential equations (PDEs) are transformed into ordinary differential equations system ODEs and obtained the reference datasets for the estimated solution dynamics of hybrid nanofluidic system. For prominent parameters, the influence of flow on the temperature distribution and velocity plot are investigated. The performance on 80\% training samples, 5\% testing and 15\% validation dataset for ANNs-BRS is well-established in terms of error histogram plots, regression analysis, and MSE based statistics. The results for entropy generation, Eckert number Ec, magnetic interaction parameter \(M\), suction parameter \(S\), and heat generation parameter \(Q\) are also discussed. The results show that the Eckert number Ec has the effect of slowing down the rate of heat transfer while increasing the temperature and increases in suction parameter causes decrease in temperature while increase in temperature profile due to enhancement of suction parameter.
{\copyright} 2023 Wiley-VCH GmbH.Quantum computation and logic. How quantum computers have inspired logical investigationshttps://zbmath.org/1530.810022024-04-15T15:10:58.286558Z"Dalla Chiara, Maria Luisa"https://zbmath.org/authors/?q=ai:dalla-chiara.maria-luisa"Giuntini, Roberto"https://zbmath.org/authors/?q=ai:giuntini.roberto"Leporini, Roberto"https://zbmath.org/authors/?q=ai:leporini.roberto"Sergioli, Guiseppe"https://zbmath.org/authors/?q=ai:sergioli.guiseppePublisher's description: This book provides a general survey of the main concepts, questions and results that have been developed in the recent interactions between quantum information, quantum computation and logic. Divided into 10 chapters, the books starts with an introduction of the main concepts of the quantum-theoretic formalism used in quantum information. It then gives a synthetic presentation of the main ``mathematical characters'' of the quantum computational game: qubits, quregisters, mixtures of quregisters, quantum logical gates. Next, the book investigates the puzzling entanglement-phenomena and logically analyses the Einstein-Podolsky-Rosen paradox and introduces the reader to quantum computational logics, and new forms of quantum logic. The middle chapters investigate the possibility of a quantum computational semantics for a language that can express sentences like ``Alice knows that everybody knows that she is pretty'', explore the mathematical concept of quantum Turing machine, and illustrate some characteristic examples that arise in the framework of musical languages. The book concludes with an analysis of recent discussions, and contains a Mathematical Appendix which is a survey of the definitions of all main mathematical concepts used in the book.Quantum entanglement and encoding algorithmhttps://zbmath.org/1530.810262024-04-15T15:10:58.286558Z"Bertini, Cesarino"https://zbmath.org/authors/?q=ai:bertini.cesarino"Leporini, Roberto"https://zbmath.org/authors/?q=ai:leporini.roberto"Moriani, Sergio"https://zbmath.org/authors/?q=ai:moriani.sergioSummary: Entanglement is a resource for quantum computation and information tasks. It has increasingly become clear that entanglement may be brought forth in combination of concepts as ``(the) Animal Acts'' or ``Animal (eats) Food'' rather than being unique to micro-physical systems like photons or electrons. We extend the approach to the combination of three concepts which determine non-classical statistical correlations. Moreover, we introduce a new vector encoding algorithm that takes entanglement into account.N-partite entanglement measures of GHZ states in a non-inertial framehttps://zbmath.org/1530.810302024-04-15T15:10:58.286558Z"Rueda-Paz, J."https://zbmath.org/authors/?q=ai:rueda-paz.juvenal"Manríquez-Zepeda, J. L."https://zbmath.org/authors/?q=ai:manriquez-zepeda.j-l"López-García, L."https://zbmath.org/authors/?q=ai:lopez-garcia.l"Ávila, M."https://zbmath.org/authors/?q=ai:avila.matias|avila.mar|avila.m-a|avila.manuelSummary: Entanglement measures of GHZ states in a non-inertial frame are analyzed. The form of the GHZ states of \(n\) entangled qubits where \(q\) of them are non-inertial observers is studied. Some generalities of the entanglement measures of GHZ states are derived. The entanglement measures depend on a parameter \(r \in [0, \pi /4]\) associated with the acceleration \(a \in [0, \infty]\) and on the number of non-inertial observers. It was observed that the negativity \(N_{1-(n-1)}\) is the same in GHZ states with the same number of non-inertial observers as long as there is at least one inertial qubit in the \((n-1)\) modes. The whole residual entanglement of GHZ states with \(q\) non-inertial observers can be increased up to \(\cos^{2q}(r)\) by increasing the number of inertial entangled qubits in it, i.e. \(n \to \infty\). It is observed that \(\cos^{2q}(r)\) is a good approximation of the whole residual entanglement for \(q \gg 1\). Using the latter, it is observed that at infinite acceleration any GHZ state with \(q \geq 4\) has an entanglement close to \(10 \%\) of the fully inertial GHZ state, and with \(n \geq 7\), this is less than \(1 \%\), which should be considered in quantum network protocols. Regarding the entropy, it was found that this is a function of a parameter \(r\), and of the number \(q\) of accelerated observers, but not of the number of entangled qubits. Finally, a formula to calculate the entropy of GHZ states in a non-inertial frame also was found.Synthesizing quantum circuits of AES with lower \(T\)-depth and less qubitshttps://zbmath.org/1530.810352024-04-15T15:10:58.286558Z"Huang, Zhenyu"https://zbmath.org/authors/?q=ai:huang.zhenyu.2"Sun, Siwei"https://zbmath.org/authors/?q=ai:sun.siweiSummary: The significant progress in the development of quantum computers has made the study of cryptanalysis based on quantum computing an active topic. To accurately estimate the resources required to carry out quantum attacks, the involved quantum algorithms have to be synthesized into quantum circuits with basic quantum gates. In this work, we present several generic synthesis and optimization techniques for circuits implementing the quantum oracles of iterative symmetric-key ciphers that are commonly employed in quantum attacks based on Grover and Simon's algorithms. Firstly, a general structure for implementing the round functions of block ciphers in-place is proposed. Then, we present some novel techniques for synthesizing efficient quantum circuits of linear and non-linear cryptographic building blocks. We apply these techniques to AES and systematically investigate the strategies for depth-width trade-offs. Along the way, we derive a quantum circuit for the AES S-box with \textit{provably} minimal \(T\)-depth based on some new observations on its classical circuit. As a result, the \(T\)-depth and width (number of qubits) required for implementing the quantum circuits of AES are significantly reduced. Compared with the circuit proposed in EUROCRYPT 2020, the \(T\)-depth is reduced from 60 to 40 without increasing the width or 30 with a slight increase in width. These circuits are fully implemented in Microsoft \(\mathrm{Q}\#\) and the source code is publicly available. Compared with the circuit proposed in [\textit{J. Zou} et al., Lect. Notes Comput. Sci. 12492, 697--726 (2020; Zbl 1521.81059)], the width of one of our circuits is reduced from 512 to 371, and the Toffoli-depth is reduced from 2016 to 1558 at the same time. Actually, we can reduce the width to 270 at the cost of increased depth. Moreover, a full spectrum of depth-width trade-offs is provided, setting new records for the synthesis and optimization of quantum circuits of AES.
For the entire collection see [Zbl 1517.94003].Correlated effects of Pauli noise on controlled teleportation of an arbitrary single-qubit state via a three-qubit W statehttps://zbmath.org/1530.810372024-04-15T15:10:58.286558Z"Peng, Jiayin"https://zbmath.org/authors/?q=ai:peng.jiayin"Yang, Zhen"https://zbmath.org/authors/?q=ai:yang.zhen"Tang, Liang"https://zbmath.org/authors/?q=ai:tang.liang"Bai, Ming-Qiang"https://zbmath.org/authors/?q=ai:bai.mingqiangSummary: The goal of this paper is to study controlled quantum teleportation (CQT for short) of an unknown single-qubit state by using a three-qubit W state as the quantum channel. The tripartite scheme is first introduced in an ideal environment, and its detailed implementation is described via the transformation of the quantum system. Then, this scheme is analyzed under two successive uses of Pauli noisy channels with memory. We give general formula quantifying the fidelity under the correlated Pauli channels. For each type of noise, the average fidelity of single-qubit CQT is calculated as a function of memory and noise parameters in the case of teleportation through a three-qubit W state in which the sender's and receiver's entangled qubits are interacted to environment during the process of entanglement distribution. The results demonstrate that the performance of the scheme is reduced in the correlated Pauli channel with partial memory, which means that the memory in this kind of noise channels will significantly weaken the communication efficiency of CQT.Performance analysis of the hardware-efficient quantum search algorithmhttps://zbmath.org/1530.810382024-04-15T15:10:58.286558Z"Ahmadkhaniha, Armin"https://zbmath.org/authors/?q=ai:ahmadkhaniha.armin"Mafi, Yousef"https://zbmath.org/authors/?q=ai:mafi.yousef"Kazemikhah, Payman"https://zbmath.org/authors/?q=ai:kazemikhah.payman"Aghababa, Hossein"https://zbmath.org/authors/?q=ai:aghababa.hossein"Barati, Masoud"https://zbmath.org/authors/?q=ai:barati.masoud"Kolahdouz, Mohammadreza"https://zbmath.org/authors/?q=ai:kolahdouz.mohammadrezaSummary: This article explores the Hardware-Efficient Quantum Search Algorithm and compares it with other well-known counterparts. Escalating the count of qubits may elevate susceptibility to errors, particularly in iterative algorithms such as Grover's. Conversely, Noisy-Intermediate-Scale-Quantum (NISQ) computers encounter limitation in the number of gates necessary for excecution of any quantum queries. Thus, we utilize hardware-efficient quantum search algorithm for further investigation due to its optimized circuit depth. Moreover, the Qiskit library and Matlab are used for validation of the analysis. Furthermore, the noise effects, encompassing phase-damping (PD) and amplitude-damping (AD) noises, are explored to present a comparative analsysis of various search algorithms.An overview of quantum cellular automatahttps://zbmath.org/1530.810392024-04-15T15:10:58.286558Z"Arrighi, P."https://zbmath.org/authors/?q=ai:arrighi.pabloSummary: Quantum cellular automata are arrays of identical finite-dimensional quantum systems, evolving in discrete-time steps by iterating a unitary operator \(G\). Moreover the global evolution \(G\) is required to be causal (it propagates information at a bounded speed) and translation-invariant (it acts everywhere the same). Quantum cellular automata provide a model/architecture for distributed quantum computation. More generally, they encompass most of discrete-space discrete-time quantum theory. We give an overview of their theory, with particular focus on structure results; computability and universality results; and quantum simulation results.Improved quantum analysis of SPECK and LowMChttps://zbmath.org/1530.810422024-04-15T15:10:58.286558Z"Jang, Kyungbae"https://zbmath.org/authors/?q=ai:jang.kyungbae"Baksi, Anubhab"https://zbmath.org/authors/?q=ai:baksi.anubhab"Kim, Hyunji"https://zbmath.org/authors/?q=ai:kim.hyunji"Seo, Hwajeong"https://zbmath.org/authors/?q=ai:seo.hwajeong"Chattopadhyay, Anupam"https://zbmath.org/authors/?q=ai:chattopadhyay.anupamSummary: As the prevalence of quantum computing is growing in leaps and bounds over the past few years, there is an ever-growing need to analyze the symmetric-key ciphers against the upcoming threat. Indeed, we have seen a number of research works dedicated to this. Our work delves into this aspect of block ciphers, with respect to the SPECK family and LowMC family.
The SPECK family received two quantum analysis till date [\textit{K. Jang} et al., ``Grover on Korean block ciphers'', Appl. Sci. (MDPI) 10, No. 18, Paper No. 6407, 25 p. (2020; \url{doi:10.3390/app10186407}); \textit{R. Anand} et al., Lect. Notes Comput. Sci. 12578, 395--413 (2020; Zbl 1500.81021)]. We revisit these two works, and present improved benchmarks SPECK (all 10 variants). Our implementations incur lower full depth compared to the previous works.
On the other hand, the quantum circuit of LowMC was explored earlier in \textit{S. Jaques} et al.'s paper [Lect. Notes Comput. Sci. 12106, 280--310 (2020; Zbl 1492.81042)]. However, there is an already known bug in their paper, which we patch. On top of that, we present two versions of LowMC (on L1, L3 and L5 variants) in quantum, both of which incur significantly less full depth than the bug-fixed implementation.
For the entire collection see [Zbl 1517.94008].Classical and quantum algorithms for assembling a text from a dictionaryhttps://zbmath.org/1530.810432024-04-15T15:10:58.286558Z"Khadiev, Kamil"https://zbmath.org/authors/?q=ai:khadiev.kamil"Remidovskii, Vladislav"https://zbmath.org/authors/?q=ai:remidovskii.vladislav(no abstract)Robust quantum secure multiparty computation protocols for minimum value calculation in collective noises and their simulationhttps://zbmath.org/1530.810442024-04-15T15:10:58.286558Z"Kong, Han-Xiao"https://zbmath.org/authors/?q=ai:kong.han-xiao"Jia, Heng-Yue"https://zbmath.org/authors/?q=ai:jia.hengyue"Wu, Xia"https://zbmath.org/authors/?q=ai:wu.xia"Li, Guo-Qing"https://zbmath.org/authors/?q=ai:li.guoqingSummary: In this paper, two quantum secure multiparty computation protocols for the logical AND (QSMC\textunderscore AND) are proposed using decoherence-free (DF) states, which can resist collective-dephasing noise and collective-rotation noise, respectively. The protocols enable the secure calculation of the logical AND value of the parties' single-bit secret with the assistance of a semi-honest third party (TP). Based on these protocols, quantum secure multiparty computation protocols for calculating the minimum value of parties' \(n\)-bit secret are also designed. Moreover, some common outsider's and insider's attacks are discussed, and the simulations of our QSMC\textunderscore AND protocols are conducted on the IBM Q cloud platform to verify the correctness and noise resistance. The results demonstrate the feasibility and effectiveness of the protocols in realistic quantum computing environments.Candidate trapdoor claw-free functions from group actions with applications to quantum protocolshttps://zbmath.org/1530.810482024-04-15T15:10:58.286558Z"Alamati, Navid"https://zbmath.org/authors/?q=ai:alamati.navid"Malavolta, Giulio"https://zbmath.org/authors/?q=ai:malavolta.giulio"Rahimi, Ahmadreza"https://zbmath.org/authors/?q=ai:rahimi.ahmadrezaSummary: Trapdoor Claw-free Functions (TCFs) are two-to-one trapdoor functions where it is computationally hard to find a claw, i.e., a colliding pair of inputs. TCFs have recently seen a surge of renewed interest due to new applications to quantum cryptography: as an example, TCFs enable a classical machine to verify that some quantum computation has been performed correctly. In this work, we propose a new family of (almost two-to-one) TCFs based on conjectured hard problems on isogeny-based group actions. This is the first candidate construction that is not based on lattice-related problems and the first scheme (from any plausible post-quantum assumption) with a \textit{deterministic} evaluation algorithm. To demonstrate the usefulness of our construction, we show that our TCF family can be used to devise a \textit{computational} test of a qubit, which is the basic building block used in the general verification of quantum computations.
For the entire collection see [Zbl 1516.94002].Nostradamus goes quantumhttps://zbmath.org/1530.810502024-04-15T15:10:58.286558Z"Benedikt, Barbara Jiabao"https://zbmath.org/authors/?q=ai:benedikt.barbara-jiabao"Fischlin, Marc"https://zbmath.org/authors/?q=ai:fischlin.marc"Huppert, Moritz"https://zbmath.org/authors/?q=ai:huppert.moritzSummary: In the Nostradamus attack, introduced by \textit{J. Kelsey} and \textit{T. Kohno} [Lect. Notes Comput. Sci. 4004, 183--200 (2006; Zbl 1140.94354)], the adversary has to commit to a hash value \(y\) of an iterated hash function \(\mathsf{H}\) such that, when later given a message prefix \(P\), the adversary is able to find a suitable ``suffix explanation'' \(S\) with \(\mathsf{H}(P\| S)=y\). Kelsey and Kohno [loc. cit.] show a herding attack with \(2^{2n/3}\) evaluations of the compression function of \(\mathsf{H}\) (with \(n\) bits output and state), locating the attack between preimage attacks and collision search in terms of complexity. Here we investigate the security of Nostradamus attacks for quantum adversaries. We present a quantum herding algorithm for the Nostradamus problem making approximately \(\sqrt[3]{n} \cdot 2^{3n/7}\) compression function evaluations, significantly improving over the classical bound. We also prove that quantum herding attacks cannot do better than \(2^{3n/7}\) evaluations for random compression functions, showing that our algorithm is (essentially) optimal. We also discuss a slightly less tight bound of roughly \(2^{3n/7-s}\) for general Nostradamus attacks against random compression functions, where \(s\) is the maximal block length of the adversarially chosen suffix \(S\).
For the entire collection see [Zbl 1517.94003].A note on the post-quantum security of (ring) signatureshttps://zbmath.org/1530.810512024-04-15T15:10:58.286558Z"Chatterjee, Rohit"https://zbmath.org/authors/?q=ai:chatterjee.rohit"Chung, Kai-Min"https://zbmath.org/authors/?q=ai:chung.kai-min"Liang, Xiao"https://zbmath.org/authors/?q=ai:liang.xiao"Malavolta, Giulio"https://zbmath.org/authors/?q=ai:malavolta.giulioSummary: This work revisits the security of classical signatures and ring signatures in a quantum world. For (ordinary) signatures, we focus on the arguably preferable security notion of blind-unforgeability recently proposed by \textit{G. Alagic} et al. [Lect. Notes Comput. Sci. 12107, 788--817 (2020; Zbl 1480.81027)]. We present two short signature schemes achieving this notion: one is in the quantum random oracle model, assuming quantum hardness of SIS; and the other is in the plain model, assuming quantum hardness of LWE with super-polynomial modulus. Prior to this work, the only known blind-unforgeable schemes are Lamport's one-time signature and the Winternitz one-time signature, and both of them are in the quantum random oracle model.
For ring signatures, the recent work by \textit{R. Chatterjee} et al. [Lect. Notes Comput. Sci. 12825, 282--312 (2021; Zbl 1485.94134)] proposes a definition trying to capture adversaries with quantum access to the signer. However, it is unclear if their definition, when restricted to the classical world, is as strong as the standard security notion for ring signatures. They also present a construction that only partially achieves (even) this seeming weak definition, in the sense that the adversary can only conduct superposition attacks over the messages, but not the rings. We propose a new definition that does not suffer from the above issue. Our definition is an analog to the blind-unforgeability in the ring signature setting. Moreover, assuming the quantum hardness of LWE, we construct a compiler converting any blind-unforgeable (ordinary) signatures to a ring signature satisfying our definition.
For the entire collection see [Zbl 1516.94001].IND-CCA security of Kyber in the quantum random oracle model, revisitedhttps://zbmath.org/1530.810522024-04-15T15:10:58.286558Z"Chen, Zhao"https://zbmath.org/authors/?q=ai:chen.zhao"Lu, Xianhui"https://zbmath.org/authors/?q=ai:lu.xianhui"Jia, Dingding"https://zbmath.org/authors/?q=ai:jia.dingding"Li, Bao"https://zbmath.org/authors/?q=ai:li.baoSummary: In this paper, we answer the open question pointed out by \textit{P. Grubbs} et al. [Lect. Notes Comput. Sci. 13277, 402--432 (2022; Zbl 1502.81027)] and \textit{K. Xagawa} [Lect. Notes Comput. Sci. 13277, 551--581 (2022; Zbl 1513.81040)], i.e., the \textit{concrete} \textsf{IND-CCA} security proof of \textsf{Kyber}. In order to add robustness, \textsf{Kyber} uses a slightly tweaked Fujisaki-Okamoto (FO) transformation. Specifically, it uses a ``double-nested-hash'' to generate the final key. This makes the proof techniques [\textit{H. Jiang} et al., Lect. Notes Comput. Sci. 10993, 96--125 (2018; Zbl 1457.94142)] of proving standard FO transformation invalid. Hence, we develop a novel approach to overcome the difficulties, and prove that \textsf{Kyber} is \textsf{IND-CCA} secure in the quantum random oracle model (QROM) if the underlying encryption scheme is \textsf{IND-CCA} secure. Our result provides a solid quantum security guarantee for the post-quantum cryptography standard of NIST competition, \textsf{Kyber} algorithm.
For the entire collection see [Zbl 1517.94007].On security notions for encryption in a quantum worldhttps://zbmath.org/1530.810532024-04-15T15:10:58.286558Z"Chevalier, Céline"https://zbmath.org/authors/?q=ai:chevalier.celine"Ebrahimi, Ehsan"https://zbmath.org/authors/?q=ai:ebrahimi.ehsan"Vu, Quoc-Huy"https://zbmath.org/authors/?q=ai:vu.quoc-huySummary: Indistinguishability against adaptive chosen-ciphertext attacks (IND-CCA2) is usually considered the most desirable security notion for classical encryption. In this work, we investigate its adaptation in the quantum world, when an adversary can perform superposition queries. The security of quantum-secure classical encryption has first been studied by \textit{D. Boneh} and \textit{M. Zhandry} [Lect. Notes Comput. Sci. 7881, 592--608 (2013; Zbl 1312.94111); Lect. Notes Comput. Sci. 8043, 361--379 (2013; Zbl 1317.81074)], but they restricted the adversary to classical challenge queries, which makes the indistinguishability only hold for classical messages (IND-qCCA2). We extend their work by giving the first security notions for fully quantum indistinguishability under quantum adaptive chosen-ciphertext attacks, where the indistinguishability holds for superposition of plaintexts (qIND-qCCA2).
For the entire collection see [Zbl 1517.94008].Exploring SAT for cryptanalysis: (quantum) collision attacks against 6-round SHA-3https://zbmath.org/1530.810542024-04-15T15:10:58.286558Z"Guo, Jian"https://zbmath.org/authors/?q=ai:guo.jian"Liu, Guozhen"https://zbmath.org/authors/?q=ai:liu.guozhen"Song, Ling"https://zbmath.org/authors/?q=ai:song.ling"Tu, Yi"https://zbmath.org/authors/?q=ai:tu.yiSummary: In this work, we focus on collision attacks against instances of \texttt{SHA}-3 hash family in both classical and quantum settings. Since the 5-round collision attacks on \texttt{SHA3}-256 and other variants proposed by \textit{J. Guo} et al. at [J. Cryptology 33, No. 1, 228--270 (2020; Zbl 1455.94160)], no other essential progress has been published. With a thorough investigation, we identify that the challenges of extending such collision attacks on \texttt{SHA}-3 to more rounds lie in the inefficiency of differential trail search. To overcome this obstacle, we develop a SAT-based automatic search toolkit. The tool is used in multiple intermediate steps of the collision attacks and exhibits surprisingly high efficiency in differential trail search and other optimization problems encountered in the process. As a result, we present the first 6-round classical collision attack on \texttt{SHAKE128} with time complexity \(2^{123.5}\), which also forms a quantum collision attack with quantum time \(2^{67.25} / \sqrt{S}\), and the first 6-round quantum collision attack on \texttt{SHA3}-224 and \texttt{SHA3}-256 with quantum time \(2^{97.75} / \sqrt{S}\) and \(2^{104.25} / \sqrt{S}\), where \(S\) represents the hardware resources of the quantum computer. The fact that classical collision attacks do not apply to 6-round \texttt{SHA3}-224 and \texttt{SHA3}-256 shows the higher coverage of quantum collision attacks, which is consistent with that on \texttt{SHA}-2 observed by \textit{A. Hosoyamada} and \textit{Y. Sasaki} at [Lect. Notes Comput. Sci. 12825, 616--646 (2021; Zbl 1487.81066)].
For the entire collection see [Zbl 1517.94003].Quantum attacks on PRFs based on public random permutationshttps://zbmath.org/1530.810552024-04-15T15:10:58.286558Z"Guo, Tingting"https://zbmath.org/authors/?q=ai:guo.tingting"Wang, Peng"https://zbmath.org/authors/?q=ai:wang.peng.4"Hu, Lei"https://zbmath.org/authors/?q=ai:hu.lei"Ye, Dingfeng"https://zbmath.org/authors/?q=ai:ye.dingfengSummary: Plenty of permutation-based pseudorandom functions (PRFs) were proposed. In order to analyze their quantum security uniformly, we proposed three general frameworks \textit{F1}, \textit{F2}, and \textit{F3} for \(n\)-to-\(n\)-bit PRFs with one, two parallel, and two serial public permutation calls respectively, where every permutation is preceded and followed by any bitwise linear mappings. We analyze them in the \textit{Q2} model where attackers have quantum-query access to PRFs and permutations. Our results show \textit{F1} is not secure with \(\mathcal{O}(n)\) quantum queries while its PRFs achieve \(n/2\)-bit security in the classical setting, and \textit{F2}, \textit{F3} are not secure with \(\mathcal{O}(2^{n/2}n)\) quantum queries while their PRFs, such as SoEM, PDMMAC, and pEDM, achieve \(2n/3\)-bit security in the classical setting. Besides, we attack three general instantiations XopEM, EDMEM, and EDMDEM of \textit{F2}, \textit{F3} with at most \(\mathcal{O}(2^{n/2}n)\) quantum queries, which derive from replacing the two PRPs in Xop, EDM, and EDMD with two independent EM constructions. We also attack pre-existing concrete PRF instantiations of \textit{F2}, \textit{F3}: DS-SoEM, PDMMAC, pEDM, and SoKAC21, with at most \(\mathcal{O}(2^{n/2}n)\) quantum queries.
For the entire collection see [Zbl 1517.94008].Game theoretic security framework for quantum key distributionhttps://zbmath.org/1530.810562024-04-15T15:10:58.286558Z"Krawec, Walter O."https://zbmath.org/authors/?q=ai:krawec.walter-o"Miao, Fei"https://zbmath.org/authors/?q=ai:miao.feiSummary: In this paper, we propose a game-theoretic model of security for quantum key distribution (QKD) protocols. QKD protocols allow two parties to agree on a shared secret key, secure against an adversary bounded only by the laws of physics (as opposed to classical key distribution protocols which, by necessity, require computational assumptions to be placed on the power of an adversary). We investigate a novel framework of security using game theory where all participants (including the adversary) are rational. We will show that, in this framework, certain impossibility results for QKD in the standard adversarial model of security still remain true here. However, we will also show that improved key-rate efficiency is possible in our game-theoretic security model.
For the entire collection see [Zbl 1398.68017].Security loophole and improvement of quantum private query protocol based on W statehttps://zbmath.org/1530.810582024-04-15T15:10:58.286558Z"Zhang, Xue"https://zbmath.org/authors/?q=ai:zhang.xue|zhang.xue.2|zhang.xue.1"Qin, Sujuan"https://zbmath.org/authors/?q=ai:qin.sujuan"Zhang, Xuanwen"https://zbmath.org/authors/?q=ai:zhang.xuanwen"Yu, Xiaoling"https://zbmath.org/authors/?q=ai:yu.xiaoling"Gao, Fei"https://zbmath.org/authors/?q=ai:gao.fei.1"Wen, Qiaoyan"https://zbmath.org/authors/?q=ai:wen.qiaoyanSummary: As an important practical cryptographic protocol, quantum key distribution (QKD)-based quantum private query (QPQ) has gained widespread attention in the past few decades. However, many of these protocols require classical post-processing, and the number of transmitted qubits is often much larger than the size of the database. Recently, \textit{R.-G. Zhou} and \textit{Y. Hua} proposed a QPQ protocol that uses the W state and relies on a third party, which only requires qubits of the same size as the database [Int. J. Theor. Phys. 60, No. 7, 2531--2542 (2021; Zbl 1528.81123)]. Unfortunately, we have discovered a potential attack strategy against this protocol. By using fake entangled photons, a dishonest third party may be able to compromise the privacy of both the database owner and the user. To address this security vulnerability, we propose an improved QPQ protocol.Post-quantum security on the Lai-Massey schemehttps://zbmath.org/1530.810592024-04-15T15:10:58.286558Z"Zhang, Zhongya"https://zbmath.org/authors/?q=ai:zhang.zhongya"Wu, Wenling"https://zbmath.org/authors/?q=ai:wu.wenling"Sui, Han"https://zbmath.org/authors/?q=ai:sui.han"Wang, Bolin"https://zbmath.org/authors/?q=ai:wang.bolinSummary: Post-quantum cryptography has attracted much attention from worldwide cryptologists. A growing number of symmetric cryptography algorithms have been analyzed in the quantum settings. Lai-Massey scheme was analysed by \textit{S. Vaudenay} in [Lect. Notes Comput. Sci. 1716, 8--19 (1999; Zbl 0977.94044)], based on the IDEA block cipher, and widely used in the design of symmetric cryptographic algorithms. In this work, we study the security on the Lai-Massey scheme in the quantum setting, and give a general technique to simulate the XOR of left and right parts of outputs of quantum oracles without destroying quantum entanglements. We show that the 3-round and 4-round Lai-Massey scheme are insecure, which can be distinguished from a random permutation in polynomial time in the quantum chosen-plaintext (qCPA) setting and quantum chosen ciphertext attack (qCCA) setting based on Simon's algorithm, respectively. We also introduce quantum key-recovery attacks on the Lai-Massey scheme by applying the combination of Simon's and Grover's algorithms. For \(r\)-round Lai-Massey scheme, the key-recovery query complexity are \(O({2^{(r - 3)k/2}})\) and \(O({2^{(r - 4)k/2}})\) in the qCPA and qCCA setting respectively, where \(k\) is the bit length of a round sub-key. The query complexities are better than the quantum brute force search by factors \({2^{3k/2}}\) and \({2^{2k}}\) respectively.Optimizing the depth of quantum implementations of linear layershttps://zbmath.org/1530.810602024-04-15T15:10:58.286558Z"Zhu, Chengkai"https://zbmath.org/authors/?q=ai:zhu.chengkai"Huang, Zhenyu"https://zbmath.org/authors/?q=ai:huang.zhenyu.2Summary: Synthesis and optimization of quantum circuits are important and fundamental research topics in quantum computation, due to the fact that qubits are very precious and decoherence time which determines the computation time available is very limited. Specifically in cryptography, identifying the minimum quantum resources for implementing an encryption process is crucial in evaluating the quantum security of symmetric-key ciphers. In this work, we investigate the problem of optimizing the depth of quantum circuits for linear layers while utilizing a small number of qubits and quantum gates. To this end, we present a framework for the implementation and optimization of linear Boolean functions, by which we significantly reduce the depth of quantum circuits for many linear layers used in symmetric-key ciphers without increasing the gate count.
For the entire collection see [Zbl 1517.94007].Free products and AQFThttps://zbmath.org/1530.811182024-04-15T15:10:58.286558Z"Tanimoto, Yoh"https://zbmath.org/authors/?q=ai:tanimoto.yohSummary: We review the free product construction of von Neumann algebras, its application to a question in Algebraic Quantum Field Theory (AQFT) and an application of AQFT techniques to a question of free products. We show the existence of half-sided modular inclusions with trivial relative commutant and nontriviality of relative commutant for an inclusion of free product von Neumann algebras.
For the entire collection see [Zbl 1492.47001].Chemically coupled Hindmarsh-Rose neurons with cross interactions between membrane potential and magnetic fluxhttps://zbmath.org/1530.830562024-04-15T15:10:58.286558Z"Remi, T."https://zbmath.org/authors/?q=ai:remi.t"Subha, P. A."https://zbmath.org/authors/?q=ai:subha.p-aSummary: In this work, we have analysed the synchronous dynamics and pattern formation in Hindmarsh-Rose neurons with cross interactions between membrane potential and magnetic flux, in the chemical mode. The self, mixed and cross interactions are realised by varying coupling phase. The magnetic flux induces plateau bursting and amplitude death in the network. The self chemical coupling induces synchrony, whereas, the cross coupling is incapable of it. However, the cross coupling acts along with self coupling to form mixed coupling and induces synchrony in the system. The stability of the synchronous state has been studied by master stability approach. The parameter space reveals the bifurcation point at which cross coupling overrides self coupling effects. The synchronising ability of interactions are justified in a network of neurons as well. The statistical factor of synchronisation quantifies the amount of synchrony in the network in different interaction modes. The combined effect of non local interactions and mixed coupling of variables initiates the emergence of chimera and multichimera states. However, in cross-coupled systems, only incoherent states are present. The existence of chimera and multichimera states are confirmed by calculating the strength of incoherence and discontinuity measure. The analysis of spatiotemporal patterns reveals the presence of travelling chimeras within the network. The Hamilton energy function indicate that a greater amount of energy is required to sustain coherent neurons at higher potential. This work may enhance the understanding of chimera states and improve its applicability to real-world systems.Optimization methods. Introduction to classical, nature analogous and neural optimizationshttps://zbmath.org/1530.900012024-04-15T15:10:58.286558Z"Hollstein, Ralf"https://zbmath.org/authors/?q=ai:hollstein.ralf.1This book ``Optimierungsmethoden -- Einführung in die klassischen, naturanalogen und neuronalen Optimierungen'' by Ralf Hollstein deliberates the pivotal role of optimization across various facets of life whether it be minimization of cost, resources, risk, processing time, environmental impact, energy consumption, travel time, or it be maximization of profit, engine performance, portfolio, production, sales, and athletic achievements. Extant literature documents the use of a vast array of methods (including their variants and subvariants) given the diverse, complex, and varied nature of real-world optimization issues problems. This book dexterously and delicately blends theory with practice by presenting its readers with a compilation of some of these principal optimization methods along with their applications in practice. Although the book describes various optimization procedures adeptly by exemplifying them without delving deeply into their theoretical aspects, it adroitly directs its readers to the relevant literature explaining them.
This book provides a comprehensive collection of classic, nature-analogous and neural optimization methods and is divided into four major parts. Part 1 covers various types of optimization problems, Part II discusses classical optimization methods, Part III includes nature-inspired optimizations and Part IV elucidates neural combinatorial optimization methods including optimization of artificial neural networks and machine learning. It introduces its readers to a new research area, viz. Neural Combinatorial Optimization (NCO), introduced by Bello et al. in 2015 (as cited by the author in the book). NCO methods signify a shift in strategy: unlike conventional heuristic programming where computers receive instructions to determine viable solutions for optimization problems, NCO methods enable computers to autonomously derive hidden heuristics using machine learning techniques like TensorFlow modules. The pivotal advantage of NCO methods lies in their applicability to practical optimization problems lacking established heuristics.
The book which serves as an introductory guide to the promising field of AI-based, self-learning optimization algorithms, intends to cater to a diverse set of audience including practitioners, researchers and scholars engaged in practical optimization as well as students in computer science, mathematics, economics, and engineering.
The list of the book's twenty seven chapters, each of them with its own scholarly references, along with their contents is as follows, translated from German: Chapter 1: Introduction, Chapter 2: Continuous optimization problems, Chapter 3: Combinatorial optimization problems, Chapter 4: Linear optimization problems, Chapter 5: Multi-criteria optimization problems, Chapter 6: Analytical methods, Chapter 7: Methods for solving combinatorial optimization problems, Chapter 8: Linear optimization, Chapter 9: Multi-criteria optimization methods, Chapter 10: Complexity and heuristic/metaheuristic methods, Chapter 11: Physics-based algorithms, Chapter 12: Evolutionary algorithms, Chapter 13: Particle swarm algorithms, Chapter 14: Ant algorithms, Chapter 15: Bee algorithms, Chapter 16: Bat algorithms, Chapter 17: Artificial immune systems, Chapter 18: Overview: Nature-analogous optimizations, Chapter 19: Neural networks, Chapter 20: Self-encouraging cards, Chapter 21: Hopfield networks, Chapter 22: Reinforcement learning, Chapter 23: Optimization methods in deep learning, Chapter 24: Neural optimization with the pointer network, Chapter 25: Neural optimization with transformer, Chapter 26: Optimization with graphical neural networks, and Chapter 27: Program libraries for machine learning.
This book, thus, provides an elaborate understanding of various optimization problems, algorithms, and methods in addition to depicting their diverse applicability to real-time real-world problems.
Given that it provides an extensive and comprehensive collection of optimization methods, this book, if translated into English or other widely-spoken languages, will be an enriching resource for the non-German-speaking audience who are interested in learning optimization methods from scratch.
Though this book extensively covers various optimization methods, many future scientific, applied, and real-world illustrations and uses can still be explored and pursued further in the vast and quickly expanding domains of modern research.
Reviewer: Gerhard-Wilhelm Weber (Poznań and Ankara) and Jinal Parikh (Ahmedabad)A memetic algorithm for restoring feasibility in scheduling with limited makespanhttps://zbmath.org/1530.900412024-04-15T15:10:58.286558Z"Mencía, Raúl"https://zbmath.org/authors/?q=ai:mencia.raul"Mencía, Carlos"https://zbmath.org/authors/?q=ai:mencia.carlos"Varela, Ramiro"https://zbmath.org/authors/?q=ai:varela.ramiro(no abstract)Tabu search algorithms for minimizing total completion time on a single machine with an actual time-dependent learning effecthttps://zbmath.org/1530.900432024-04-15T15:10:58.286558Z"Zheng, Chunhui"https://zbmath.org/authors/?q=ai:zheng.chunhui"Chen, Huaping"https://zbmath.org/authors/?q=ai:chen.huaping"Xu, Rui"https://zbmath.org/authors/?q=ai:xu.rui.3Summary: In this paper, we investigate a single machine problem with actual time-dependent learning effect considering unequal release times, where the objective is to minimize the total completion time. At first, a mathematical model of the problem was formulated, which was verified to be effective by ILOG CP (a constraint programming tool provided by ILOG). Then a branch-and-bound algorithm incorporating with two dominance properties and two lower bounds was developed to obtain solutions for small size problems. However, since this problem is NP-hard, two tabu search algorithms combined with dominance rules, called TSDR, were proposed for solving problems with large number of jobs. The experimental results demonstrated that the proposed branch-and-bound algorithm had a better performance than CP in small size problems. The TSDR algorithms can also obtain optimal solutions for some situations in small problems. In addition, the proposed TSDR algorithms outperformed the benchmark algorithms in the literature and the advantage became more obvious with the number of jobs increasing.The cross-border e-commerce platform selection based on the probabilistic dual hesitant fuzzy generalized dice similarity measureshttps://zbmath.org/1530.900472024-04-15T15:10:58.286558Z"Ning, Baoquan"https://zbmath.org/authors/?q=ai:ning.baoquan"Wei, Guiwu"https://zbmath.org/authors/?q=ai:wei.guiwuSummary: Cross-border e-commerce platform (CBECP) plays a very important role in the development of a cross-border e-commerce (CBEC). How to select the best CBECP scientifically and reasonably is a very critical multi-attribute group decision-making (MAGDM) issue. With the uncertainty of people's cognition of the objective world, the decision-making process is full of a lot of fuzzy information. In view of the great advantages of probabilistic dual hesitation fuzzy set (FS) in expressing decision-making information, and in combination with the very extensive use of the Dice similarity measure (DSM), a new MAGDM method is proposed for the optimal CBECP selection (CBECPS) under the probabilistic dual hesitation fuzzy (PDHF) environment. First, on the basis of reviewing a large number of documents on the CBECPS for CBEC, the evaluation index system for the CBECPS is constructed; second, several new DSMs are proposed in the PDHF environment; third, based on the two newly proposed probabilistic dual hesitant weighted generalized Dice similarity measures, two novel MAGDM methods are provided for CBECPS, which are used for CBECPS; finally, the two established MAGDM techniques are compared with the existing decision-making methods, and the parameter analysis is carried out to illustrate the effectiveness and superiority of the two established MAGDM techniques. The two established techniques can not only be used for CBECPS of CBEC, but also be extended to similar related research.New bounds on augmenting steps of block-structured integer programshttps://zbmath.org/1530.900542024-04-15T15:10:58.286558Z"Chen, Lin"https://zbmath.org/authors/?q=ai:chen.lin.1"Koutecký, Martin"https://zbmath.org/authors/?q=ai:koutecky.martin"Xu, Lei"https://zbmath.org/authors/?q=ai:xu.lei.1"Shi, Weidong"https://zbmath.org/authors/?q=ai:shi.weidongSummary: Iterative augmentation has recently emerged as an overarching method for solving Integer Programs (IP) in variable dimension, in stark contrast with the volume and flatness techniques of IP in fixed dimension. Here we consider \(4\)-block \(n\)-fold integer programs, which are the most general class considered so far. A \(4\)-block \(n\)-fold IP has a constraint matrix which consists of \(n\) copies of small matrices \(A\), \(B\), and \(D\), and one copy of \(C\), in a specific block structure. Iterative augmentation methods rel\(y\) on the so-called Graver basis of the constraint matrix, which constitutes a set of fundamental augmenting steps. All existing algorithms rely on bounding the \(\ell_1\)- or \(\ell_\infty\)-norm of elements of the Graver basis. \textit{R. Hemmecke} et al. [Math. Program. 145, No. 1--2 (A), 1--18 (2014; Zbl 1298.90057)] showed that \(4\)-block \(n\)-fold IP has Graver elements of \(\ell_\infty\)-norm at most \(\mathcal{O}_\mathrm{FPT}(n^{2^{s_D}})\), leading to an algorithm with a similar runtime; here, \(s_D\) is the number of rows of matrix \(D\) and \(\mathcal{O}_\mathrm{FPT}\) hides a multiplicative factor that is only dependent on the small matrices \(A\), \(B\), \(C\), \(D\). However, it remained open whether their bounds are tight, in particular, whether they could be improved to \(\mathcal{O}_\mathrm{FPT}(1)\), perhaps at least in some restricted cases.\par We prove that the \(\ell_\infty\)-norm of the Graver elements of \(4\)-block \(n\)-fold IP is upper bounded by \(\mathcal{O}_\mathrm{FPT}(n^{s_D})\), improving significantly over the previous bound \(\mathcal{O}_\mathrm{FPT}(n^{2^{s_D}})\). We also provide a matching lower bound of \(\Omega(n^{s_D})\) which even holds for arbitrary non-zero lattice elements, ruling out augmenting algorithm relying on even more restricted notions of augmentation than the Graver basis. We then consider a special case of \(4\)-block \(n\)-fold in which \(C\) is a zero matrix, called \(3\)-block \(n\)-fold IP. We show that while the \(\ell_\infty\)-norm of its Graver elements is \(\Omega(n^{s_D})\), there exists a different decomposition into lattice elements whose \(\ell_\infty\)-norm is bounded by \(\mathcal{O}_\mathrm{FPT}(1)\), which allows us to provide improved upper bounds on the \(\ell_\infty\)-norm of Graver elements for \(3\)-block \(n\)-fold IP. The key difference between the respective decompositions is that a Graver basis guarantees a sign-compatible decomposition; this property is critical in applications because it guarantees each step of the decomposition to be feasible. Consequently, our improved upper bounds let us establish faster algorithms for \(3\)-block \(n\)-fold IP and 4-block IP, and our lower bounds strongly hint at parameterized hardness of \(4\)-block and even \(3\)-block \(n\)-fold IP. Furthermore, we show that \(3\)-block \(n\)-fold IP is without loss of generality in the sense that \(4\)-block \(n\)-fold IP can be solved in FPT oracle time by taking an algorithm for \(3\)-block \(n\)-fold IP as an oracle.
For the entire collection see [Zbl 1445.68017].A simplified convergence theory for Byzantine resilient stochastic gradient descenthttps://zbmath.org/1530.900652024-04-15T15:10:58.286558Z"Roberts, Lindon"https://zbmath.org/authors/?q=ai:roberts.lindon"Smyth, Edward"https://zbmath.org/authors/?q=ai:smyth.edward-sSummary: In distributed learning, a central server trains a model according to updates provided by nodes holding local data samples. In the presence of one or more malicious servers sending incorrect information (a Byzantine adversary), standard algorithms for model training such as stochastic gradient descent (SGD) fail to converge. In this paper, we present a simplified convergence theory for the generic Byzantine Resilient SGD method originally proposed by \textit{P. Blanchard} et al. [``Machine learning with adversaries: Byzantine tolerant gradient descent'', in: NIPS'17: Proceedings of the 31st international conference on neural information processing systems. Red Hook, NY: Curran Associates, Inc. 118--128 (2017)]. Compared to the existing analysis, we shown convergence to a stationary point in expectation under standard assumptions on the (possibly nonconvex) objective function and flexible assumptions on the stochastic gradients.Direct nonlinear accelerationhttps://zbmath.org/1530.900742024-04-15T15:10:58.286558Z"Dutta, Aritra"https://zbmath.org/authors/?q=ai:dutta.aritra"Bergou, El Houcine"https://zbmath.org/authors/?q=ai:bergou.el-houcine"Xiao, Yunming"https://zbmath.org/authors/?q=ai:xiao.yunming"Canini, Marco"https://zbmath.org/authors/?q=ai:canini.marco"Richtárik, Peter"https://zbmath.org/authors/?q=ai:richtarik.peterSummary: Optimization acceleration techniques such as momentum play a key role in state-of-the-art machine learning algorithms. Recently, generic vector sequence extrapolation techniques, such as regularized nonlinear acceleration (RNA) of \textit{D. Scieur} et al. [``Regularized nonlinear acceleration'', in: Proceedings of the 30th international conference on neural information processing systems, NIPS'16. Red Hook, NY: Curran Associates Inc. 712--720 (2016)], were proposed and shown to accelerate fixed point iterations. In contrast to RNA which computes extrapolation coefficients by (approximately) setting the gradient of the objective function to zero at the extrapolated point, we propose a more direct approach, which we call \textit{direct nonlinear acceleration (DNA)}. In DNA, we aim to minimize (an approximation of) the function value at the extrapolated point instead. We adopt a regularized approach with regularizers designed to prevent the model from entering a region in which the functional approximation is less precise. While the computational cost of DNA is comparable to that of RNA, our direct approach significantly outperforms RNA on both synthetic and real-world datasets. While the focus of this paper is on convex problems, we obtain very encouraging results in accelerating the training of neural networks.The regularized stochastic Nesterov's accelerated quasi-Newton method with applicationshttps://zbmath.org/1530.900762024-04-15T15:10:58.286558Z"Makmuang, Dawrawee"https://zbmath.org/authors/?q=ai:makmuang.dawrawee"Suppalap, Siwakon"https://zbmath.org/authors/?q=ai:suppalap.siwakon"Wangkeeree, Rabian"https://zbmath.org/authors/?q=ai:wangkeeree.rabianSummary: The stochastic Broyden-Fletcher-Goldfarb-Shanno (BFGS) method has effectively solved strongly convex optimization problems. However, this method frequently encounters the near-singularity problem of the Hessian. Additionally, obtaining the optimal solution necessitates a long convergence time. In this paper, we present a regularized stochastic Nesterov's accelerated quasi-Newton method that combines Nesterov acceleration with a novel momentum coefficient to effectively accelerate convergence speed and avoid the near-singularity problem of the Hessian update in the stochastic BFGS method. Moreover, we show the almost sure convergence of the generated subsequence of iterates to an optimal solution of the strongly convex optimization problems. We examined our approach to real-world datasets. The experiment results confirmed the effectiveness and superiority of the proposed method compared with other methods in solving classification problems.Understanding measure-driven algorithms solving irreversibly ill-conditioned problemshttps://zbmath.org/1530.900852024-04-15T15:10:58.286558Z"Sawicki, Jakub"https://zbmath.org/authors/?q=ai:sawicki.jakub"Łoś, Marcin"https://zbmath.org/authors/?q=ai:los.marcin-m"Smołka, Maciej"https://zbmath.org/authors/?q=ai:smolka.maciej"Schaefer, Robert"https://zbmath.org/authors/?q=ai:schaefer.robert-lSummary: The paper helps to understand the essence of stochastic population-based searches that solve ill-conditioned global optimization problems. This condition manifests itself by presence of lowlands, i.e., connected subsets of minimizers of positive measure, and inability to regularize the problem. We show a convenient way to analyze such search strategies as dynamic systems that transform the sampling measure. We can draw informative conclusions for a class of strategies with a focusing heuristic. For this class we can evaluate the amount of information about the problem that can be gathered and suggest ways to verify stopping conditions. Next, we show the Hierarchic Memetic Strategy coupled with Multi-Winner Evolutionary Algorithm (HMS/MWEA) that follow the ideas from the first part of the paper. We introduce a complex, ergodic Markov chain of their dynamics and prove an asymptotic guarantee of success. Finally, we present numerical solutions to ill-conditioned problems: two benchmarks and a real-life engineering one, which show the strategy in action. The paper recalls and synthesizes some results already published by authors, drawing new qualitative conclusions. The totally new parts are Markov chain models of the HMS structure of demes and of the MWEA component, as well as the theorem of their ergodicity.Interactive portfolio selection involving multicriteria sorting modelshttps://zbmath.org/1530.900972024-04-15T15:10:58.286558Z"Tlili, Ali"https://zbmath.org/authors/?q=ai:tlili.ali-sghaier"Khaled, Oumaima"https://zbmath.org/authors/?q=ai:khaled.oumaima"Mousseau, Vincent"https://zbmath.org/authors/?q=ai:mousseau.vincent-a"Ouerdane, Wassila"https://zbmath.org/authors/?q=ai:ouerdane.wassilaSummary: Given a set of items, the portfolio selection problem involves selecting a subset of the items subject to resource constraints. We propose in this paper a multiobjective interactive approach based on a constrained Non-Compensatory Sorting model which integrates preferences both on items and portfolios in the same device. More precisely, we combine two evaluations models. The first one assigns items into two categories (Good / Bad) and model resource limitation using weighted cardinality constraints in such a way that the portfolio is composed of the items assigned to the good category. The second evaluation level compares portfolios on a set of portfolio-related criteria. We learn the constrained sorting model, based on a learning set, with SAT/MaxSAT language, which proves to be efficient for the preference learning task.Decentralized personalized federated learning: lower bounds and optimal algorithm for all personalization modeshttps://zbmath.org/1530.901032024-04-15T15:10:58.286558Z"Sadiev, Abdurakhmon"https://zbmath.org/authors/?q=ai:sadiev.abdurakhmon"Borodich, Ekaterina"https://zbmath.org/authors/?q=ai:borodich.ekaterina"Beznosikov, Aleksandr"https://zbmath.org/authors/?q=ai:beznosikov.aleksandr"Dvinskikh, Darina"https://zbmath.org/authors/?q=ai:dvinskikh.darina"Chezhegov, Saveliy"https://zbmath.org/authors/?q=ai:chezhegov.savelii"Tappenden, Rachael"https://zbmath.org/authors/?q=ai:tappenden.rachael"Takáč, Martin"https://zbmath.org/authors/?q=ai:takac.martin"Gasnikov, Alexander"https://zbmath.org/authors/?q=ai:gasnikov.aleksandr-vSummary: This paper considers the problem of decentralized, personalized federated learning. For centralized personalized federated learning, a penalty that measures the deviation from the local model and its average, is often added to the objective function. However, in a decentralized setting this penalty is expensive in terms of communication costs, so here, a different penalty -- one that is built to respect the structure of the underlying computational network -- is used instead. We present lower bounds on the communication and local computation costs for this problem formulation and we also present provably optimal methods for decentralized personalized federated learning. Numerical experiments are presented to demonstrate the practical performance of our methods.The influence of fitness landscape characteristics on particle swarm optimisershttps://zbmath.org/1530.901152024-04-15T15:10:58.286558Z"Engelbrecht, A. P."https://zbmath.org/authors/?q=ai:engelbrecht.andries-petrus"Bosman, P."https://zbmath.org/authors/?q=ai:bosman.peter-a-n"Malan, K. M."https://zbmath.org/authors/?q=ai:malan.katherine-m(no abstract)A new taxonomy of global optimization algorithmshttps://zbmath.org/1530.901162024-04-15T15:10:58.286558Z"Stork, Jörg"https://zbmath.org/authors/?q=ai:stork.jorg"Eiben, A. E."https://zbmath.org/authors/?q=ai:eiben.agoston-endre"Bartz-Beielstein, Thomas"https://zbmath.org/authors/?q=ai:bartz-beielstein.thomasSummary: Surrogate-based optimization, nature-inspired metaheuristics, and hybrid combinations have become state of the art in algorithm design for solving real-world optimization problems. Still, it is difficult for practitioners to get an overview that explains their advantages in comparison to a large number of available methods in the scope of optimization. Available taxonomies lack the embedding of current approaches in the larger context of this broad field. This article presents a taxonomy of the field, which explores and matches algorithm strategies by extracting similarities and differences in their search strategies. A particular focus lies on algorithms using surrogates, nature-inspired designs, and those created by automatic algorithm generation. The extracted features of algorithms, their main concepts, and search operators, allow us to create a set of classification indicators to distinguish between a small number of classes. The features allow a deeper understanding of components of the search strategies and further indicate the close connections between the different algorithm designs. We present intuitive analogies to explain the basic principles of the search algorithms, particularly useful for novices in this research field. Furthermore, this taxonomy allows recommendations for the applicability of the corresponding algorithms.Semanticshttps://zbmath.org/1530.910022024-04-15T15:10:58.286558Z"Kornai, András"https://zbmath.org/authors/?q=ai:kornai.andrasPublisher's description: The focus of this textbook is the meaning of linguistic expressions, typically full sentences and longer texts. The author describes the conceptual and formal tools required for building semantic systems capable of understanding text, both for specific tasks such as information extraction and question answering and for broad undertakings such as the Semantic Web. The goal here is to present the fundamental ideas that working systems rest on, and this book is aimed primarily at Computer Science or Engineering students interested in developing semantic systems. The ideal reader is a ``hacker'', a person who delights in having an intimate understanding of the internal workings of a system.Complex networks XIV. Proceedings of the 14th conference on complex networks, CompleNet 2023, Aveiro, Portugal, 24--28 April, 2023https://zbmath.org/1530.910102024-04-15T15:10:58.286558ZPublisher's description: This book contains contributions in the area of Network Science, presented at the 14th International Conference on Complex Networks (CompleNet), 24--28 April, 2023 in Aveiro, Portugal. CompleNet is an international conference on complex networks that brings together researchers and practitioners from diverse disciplines -- from sociology, biology, physics, and computer science -- who share a passion to better understand the interdependencies within and across systems. CompleNet is a venue to discuss ideas and findings about all types networks, from biological, to technological, to informational and social. It is this interdisciplinary nature of complex networks that CompleNet aims to explore and celebrate.
The audience of the work are professionals and academics working in Network Science, a highly-multidisciplinary field.
The articles of mathematical interest will be reviewed individually. For the 12th conference see [Zbl 1481.91005].Heterogeneous multi-player imitation learninghttps://zbmath.org/1530.910182024-04-15T15:10:58.286558Z"Lian, Bosen"https://zbmath.org/authors/?q=ai:lian.bosen"Xue, Wenqian"https://zbmath.org/authors/?q=ai:xue.wenqian"Lewis, Frank L."https://zbmath.org/authors/?q=ai:lewis.frank-l(no abstract)Hedonic diversity games: a complexity picture with more than two colorshttps://zbmath.org/1530.910352024-04-15T15:10:58.286558Z"Ganian, Robert"https://zbmath.org/authors/?q=ai:ganian.robert"Hamm, Thekla"https://zbmath.org/authors/?q=ai:hamm.thekla"Knop, Dušan"https://zbmath.org/authors/?q=ai:knop.dusan"Schierreich, Šimon"https://zbmath.org/authors/?q=ai:schierreich.simon"Suchý, Ondřej"https://zbmath.org/authors/?q=ai:suchy.ondrejSummary: Hedonic diversity games are a variant of the classical hedonic games designed to better model a variety of questions concerning diversity and fairness. Previous works mainly targeted the case with two diversity classes (represented as colors in the model) and provided some initial complexity-theoretic and existential results concerning Nash and individually stable outcomes. Here, we design new algorithms accompanied with lower bounds which provide a comprehensive parameterized-complexity picture for computing Nash and individually stable outcomes with respect to the most natural parameterizations of the problem. Crucially, our results hold for general hedonic diversity games where the number of colors is not necessarily restricted to two, and show that -- apart from two trivial cases -- a necessary condition for tractability in this setting is that the number of colors is bounded by the parameter. Moreover, for the special case of two colors we resolve an open question asked in previous work [\textit{N. Boehmer} and \textit{E. Elkind}, ``Individual-based stability in hedonic diversity games'', Preprint, \url{arXiv:1911.08669}].A cellular automaton for blocking queen gameshttps://zbmath.org/1530.911062024-04-15T15:10:58.286558Z"Cook, Matthew"https://zbmath.org/authors/?q=ai:cook.matthew"Larsson, Urban"https://zbmath.org/authors/?q=ai:larsson.urban"Neary, Turlough"https://zbmath.org/authors/?q=ai:neary.turloughSummary: We show that the winning positions of a certain type of two-player game form interesting patterns which often defy analysis, yet can be computed by a cellular automaton. The game, known as Blocking Wythoff Nim, consists of moving a queen as in chess, but always towards \((0, 0)\), and it may not be moved to any of \(k-1\) temporarily ``blocked'' positions specified on the previous turn by the other player. The game ends when a player wins by blocking all possible moves of the other player. The value of \(k\) is a parameter that defines the game, and the pattern of winning positions can be very sensitive to \(k\). As \(k\) becomes large, parts of the pattern of winning positions converge to recurring chaotic patterns that are independent of \(k\). The patterns for large \(k\) display an unprecedented amount of self-organization at many scales, and here we attempt to describe the self-organized structure that appears. This paper extends a previous study [the authors, Lect. Notes Comput. Sci. 9099, 71--84 (2015; Zbl 1432.91030)], containing further analysis and new insights into the long term behaviour and structures generated by our blocking queen cellular automaton.Sprague-Grundy values and complexity for LCTRhttps://zbmath.org/1530.911082024-04-15T15:10:58.286558Z"Gottlieb, Eric"https://zbmath.org/authors/?q=ai:gottlieb.eric"Krnc, Matjaž"https://zbmath.org/authors/?q=ai:krnc.matjaz"Muršič, Peter"https://zbmath.org/authors/?q=ai:mursic.peterSummary: Given an integer partition of \(n\), we consider the impartial combinatorial game LCTR in which moves consist of removing either the left column or top row of its Young diagram. We show that for both normal and misère play, the optimal strategy can consist mostly of mirroring the opponent's moves. We also establish that both LCTR and Downright are domestic as well as returnable, and on the other hand neither tame nor forced.
For both games, those structural observations allow for computing the Sprague-Grundy value any position in \(O(\log (n))\) time, assuming that the time unit allows for reading an integer, or performing a basic arithmetic operation. This improves on the previously known bound of \(O(n)\) due to \textit{J. Ilić} [``Computing Sprague-Grundy values for arbitrary partitions'', Preprint, \url{doi:10.5281/zenodo.6782383}]. We also cover some other complexity measures of both games, such as state-space complexity, and number of leaves and nodes in the corresponding game tree.Optimal schemes for combinatorial query problems with integer feedbackhttps://zbmath.org/1530.911092024-04-15T15:10:58.286558Z"Martinsson, Anders"https://zbmath.org/authors/?q=ai:martinsson.andersSummary: A \textit{query game} is a pair of a set \(Q\) of \textit{queries} and a set \(\mathcal{F}\) of functions, or \textit{codewords} \(f : Q \to \mathbb{Z} .\) We think of this as a two-player game. One player, Codemaker, picks a hidden codeword \(f \in \mathcal{F} \). The other player, Codebreaker, then tries to determine \(f\) by asking a sequence of queries \(q \in Q\), after each of which Codemaker must respond with the value \(f(q)\). The goal of Codebreaker is to uniquely determine \(f\) using as few queries as possible. Two classical examples of such games are coin-weighing with a spring scale, and Mastermind, which are of interest both as recreational games and for their connection to information theory.
In this paper, we will present a general framework for finding short solutions to query games. As applications, we give new self-contained proofs of the query complexity of variations of the coin-weighing problems, and prove new results that the deterministic query complexity of Mastermind with \(n\) positions and \(k\) colors is \(\Theta(n \log k / \log n + k)\) if only black-peg information is provided, and \(\Theta(n \log k / \log n + k / n)\) if both black- and white-peg information is provided. In the deterministic setting, these are the first up to constant factor optimal solutions to Mastermind known for any \(k \geqslant n^{1-o(1)}\).Hardness and algorithms for electoral manipulation under media influencehttps://zbmath.org/1530.911702024-04-15T15:10:58.286558Z"Tao, Liangde"https://zbmath.org/authors/?q=ai:tao.liangde"Chen, Lin"https://zbmath.org/authors/?q=ai:chen.lin.1"Xu, Lei"https://zbmath.org/authors/?q=ai:xu.lei.1"Xu, Shouhuai"https://zbmath.org/authors/?q=ai:xu.shouhuai"Gao, Zhimin"https://zbmath.org/authors/?q=ai:gao.zhimin"Shi, Weidong"https://zbmath.org/authors/?q=ai:shi.weidong"Huang, Dian"https://zbmath.org/authors/?q=ai:huang.dianSummary: In this paper, we study a generalization of the classic bribery problem known as electoral manipulation under media influence (EMMI). This model is motivated by modern political campaigns where candidates try to convince voters through advertising in media (TV, newspaper, Internet). When compared with the classical bribery problem, the attacker in this setting cannot directly change opinions of individual voters, but instead can execute influences via a set of manipulation strategies (e.g., advertising on a TV channel). Different manipulation strategies incur different costs and influence different subsets of voters. Once receiving a significant amount of influence, a voter will change opinion. To characterize the opinion change of each voter, we adopt the well-accepted threshold model. We prove the NP-hardness of the EMMI problem and give a dynamic programming algorithm that runs in polynomial time for a restricted case of the EMMI problem.
For the entire collection see [Zbl 1516.68009].Generative AI and deceptive news consumptionhttps://zbmath.org/1530.913082024-04-15T15:10:58.286558Z"Sandrini, Luca"https://zbmath.org/authors/?q=ai:sandrini.luca"Somogyi, Robert"https://zbmath.org/authors/?q=ai:somogyi.robertSummary: In this paper, we analyze the effects of advancements in generative artificial intelligence (GenAI) on the news media market. We model a representative consumer who allocates their time between reading news and deceptive articles. We find that GenAI may induce consumers to inefficiently reallocate their time and increase the consumption of the lower value good, i.e. deceptive content (clickbait articles or fake news). Therefore, early-stage GenAI distorts the incentives of consumers and reduces their welfare. After GenAI technology reaches a certain threshold, however, consumers start benefiting from its advancements. Finally, we find that the negative effects of early-stage GenAI are exacerbated as they induce a lower level of investment in news production.Deep equilibrium netshttps://zbmath.org/1530.913162024-04-15T15:10:58.286558Z"Azinovic, Marlon"https://zbmath.org/authors/?q=ai:azinovic.marlon"Gaegauf, Luca"https://zbmath.org/authors/?q=ai:gaegauf.luca"Scheidegger, Simon"https://zbmath.org/authors/?q=ai:scheidegger.simonSummary: We introduce deep equilibrium nets (DEQNs) -- a deep learning-based method to compute approximate functional rational expectations equilibria of economic models featuring a significant amount of heterogeneity, uncertainty, and occasionally binding constraints. DEQNs are neural networks trained in an unsupervised fashion to satisfy all equilibrium conditions along simulated paths of the economy. Since DEQNs approximate the equilibrium functions directly, simulating the economy is computationally cheap, and training data can be generated at virtually zero cost. We demonstrate that DEQNs can accurately solve economically relevant models by applying them to two challenging life-cycle models and a Bewley-style model with aggregate risk.
{{\copyright} 2022 The Authors. \textit{International Economic Review} published by Wiley Periodicals LLC on behalf of the Economics Department of the University of Pennsylvania and the Osaka University Institute of Social and Economic Research Association.}Using machine learning to capture heterogeneity in trade agreementshttps://zbmath.org/1530.913462024-04-15T15:10:58.286558Z"Baier, Scott L."https://zbmath.org/authors/?q=ai:baier.scott-l"Regmi, Narendra R."https://zbmath.org/authors/?q=ai:regmi.narendra-rSummary: This paper uses machine learning techniques to capture heterogeneity in free trade agreements. The tools of machine learning allow us to quantify several features of trade agreements, including volume, comprehensiveness, and legal enforceability. Combining machine learning results with gravity analysis of trade, we find that more comprehensive agreements result in larger estimates of the impact of trade agreements. In addition, we identify the policy provisions that have the most substantial effect on creating trade flows. In particular, legally binding provisions on antidumping, capital mobility, competition, customs harmonization, dispute settlement mechanism, e-commerce, environment, export and import restrictions, freedom of transit, investment, investor-state dispute settlement, labor, public procurement, sanitary and phytosanitary measures, services, technical barriers to trade, telecommunications, and transparency tend to have the largest trade creation effects.Rejection-proof mechanisms for multi-agent kidney exchangehttps://zbmath.org/1530.914292024-04-15T15:10:58.286558Z"Blom, Danny"https://zbmath.org/authors/?q=ai:blom.danny"Smeulders, Bart"https://zbmath.org/authors/?q=ai:smeulders.bart"Spieksma, Frits"https://zbmath.org/authors/?q=ai:spieksma.frits-c-rSummary: Kidney exchange programs (KEPs) increase kidney transplantation by facilitating the exchange of incompatible donors. Increasing the scale of KEPs leads to more opportunities for transplants. Collaboration between transplant organizations (agents) is thus desirable. As agents are primarily interested in providing transplants for their own patients, collaboration requires balancing individual and common objectives. In this paper, we consider ex-post strategic behavior, where agents can modify a proposed set of kidney exchanges. We introduce the class of rejection-proof mechanisms, which propose a set of exchanges such that agents have no incentive to reject them. We provide an exact mechanism and establish that the underlying optimization problem is \(\Sigma_2^{\mathrm{P}}\)-hard; we also describe computationally less demanding heuristic mechanisms. We show rejection-proofness can be achieved at a limited cost for typical instances. Furthermore, our experiments show that the proposed rejection-proof mechanisms also remove incentives for strategic behavior in the ex-ante setting, where agents withhold information.Distributed energy resources flexibility as volumetric options on electricityhttps://zbmath.org/1530.914512024-04-15T15:10:58.286558Z"Geman, Helyette"https://zbmath.org/authors/?q=ai:geman.helyette"Ma, Yuanye"https://zbmath.org/authors/?q=ai:ma.yuanyeSummary: The goal of the paper is twofold: a) following the identification of the merits of distributed energy resources (DERs) by FERC 2222 for the flexibility they bring to the grid, we recognize water heaters and thermostats as mini-batteries and introduce volumetric/swing options that the aggregator can sell by shifting consumers' consumption while rewarding them; b) we propose to address the pricing complexity of these volumetric options - which are in our setting very general in terms of number of exercises and quantities constraints - by a novel approach that combines Monte Carlo simulations and recurrent neural networks (RNN).Distributionally robust end-to-end portfolio constructionhttps://zbmath.org/1530.915222024-04-15T15:10:58.286558Z"Costa, Giorgio"https://zbmath.org/authors/?q=ai:costa.giorgio"Iyengar, Garud N."https://zbmath.org/authors/?q=ai:iyengar.garud-nSummary: We propose an end-to-end distributionally robust system for portfolio construction that integrates the asset return prediction model with a distributionally robust portfolio optimization model. We also show how to learn the risk-tolerance parameter and the degree of robustness directly from data. End-to-end systems have an advantage in that information can be communicated between the prediction and decision layers during training, allowing the parameters to be trained for the final task rather than solely for predictive performance. However, existing end-to-end systems are not able to quantify and correct for the impact of model risk on the decision layer. Our proposed distributionally robust end-to-end portfolio selection system explicitly accounts for the impact of model risk. The decision layer chooses portfolios by solving a minimax problem where the distribution of the asset returns is assumed to belong to an ambiguity set centered around a nominal distribution. Using convex duality, we recast the minimax problem in a form that allows for efficient training of the end-to-end system.Pricing options on flow forwards by neural networks in a Hilbert spacehttps://zbmath.org/1530.915622024-04-15T15:10:58.286558Z"Benth, Fred Espen"https://zbmath.org/authors/?q=ai:benth.fred-espen"Detering, Nils"https://zbmath.org/authors/?q=ai:detering.nils"Galimberti, Luca"https://zbmath.org/authors/?q=ai:galimberti.lucaSummary: We propose a new methodology for pricing options on flow forwards by applying infinite-dimensional neural networks. We recast the pricing problem as an optimisation problem in a Hilbert space of real-valued functions on the positive real line, which is the state space for the term structure dynamics. This optimisation problem is solved by using a feedforward neural network architecture designed for approximating continuous functions on the state space. The proposed neural network is built upon the basis of the Hilbert space. We provide case studies that show its numerical efficiency, with superior performance over that of a classical neural network trained on sampling the term structure curves.Deep reinforcement learning for option pricing and hedging under dynamic expectile risk measureshttps://zbmath.org/1530.915722024-04-15T15:10:58.286558Z"Marzban, Saeed"https://zbmath.org/authors/?q=ai:marzban.saeed"Delage, Erick"https://zbmath.org/authors/?q=ai:delage.erick"Li, Jonathan Yu-Meng"https://zbmath.org/authors/?q=ai:li.jonathan-yu-mengSummary: Recently equal risk pricing, a framework for fair derivative pricing, was extended to consider dynamic risk measures. However, all current implementations either employ a static risk measure that violates time consistency, or are based on traditional dynamic programing solution schemes that are impracticable in problems with a large number of underlying assets (due to the curse of dimensionality) or with incomplete asset dynamics information. In this paper, we extend for the first time a famous off-policy deterministic actor-critic deep reinforcement learning (ACRL) algorithm to the problem of solving a risk averse Markov decision process that models risk using a time consistent recursive expectile risk measure. This new ACRL algorithm allows us to identify high quality time consistent hedging policies (and equal risk prices) for options, such as basket options, that cannot be handled using traditional methods, or in context where only historical trajectories of the underlying assets are available. Our numerical experiments, which involve both a simple vanilla option and a more exotic basket option, confirm that the new ACRL algorithm can produce (1) in simple environments, nearly optimal hedging policies, and highly accurate prices, simultaneously for a range of maturities (2) in complex environments, good quality policies and prices using reasonable amount of computing resources; and (3) overall, hedging strategies that actually outperform the strategies produced using static risk measures when the risk is evaluated at later points of time.Arbitrage-free implied volatility surface generation with variational autoencodershttps://zbmath.org/1530.915752024-04-15T15:10:58.286558Z"Ning, Brian (Xin)"https://zbmath.org/authors/?q=ai:ning.brian"Jaimungal, Sebastian"https://zbmath.org/authors/?q=ai:jaimungal.sebastian"Zhang, Xiaorong"https://zbmath.org/authors/?q=ai:zhang.xiaorong"Bergeron, Maxime"https://zbmath.org/authors/?q=ai:bergeron.maximeSummary: We propose a hybrid method for generating arbitrage-free implied volatility (IV) surfaces consistent with historical data by combining model-free variational autoencoders (VAEs) with continuous time stochastic differential equation (SDE) driven models. We focus on two classes of SDE models: regime switching models and Lévy additive processes. By projecting historical surfaces onto the space of SDE model parameters, we obtain a distribution on the parameter subspace faithful to the data on which we then train a VAE. Arbitrage-free IV surfaces are then generated by sampling from the posterior distribution on the latent space, decoding to obtain SDE model parameters, and finally mapping those parameters to IV surfaces. We further refine the VAE model by including conditional features and demonstrate its superior generative out-of-sample performance. Finally, we showcase how our method can be used as a data augmentation tool to help practitioners manage the tail risk of option portfolios.A neuro-structural framework for bankruptcy predictionhttps://zbmath.org/1530.915852024-04-15T15:10:58.286558Z"Charalambous, Christakis"https://zbmath.org/authors/?q=ai:charalambous.christakis"Martzoukos, Spiros H."https://zbmath.org/authors/?q=ai:martzoukos.spiros-h"Taoushianis, Zenon"https://zbmath.org/authors/?q=ai:taoushianis.zenonSummary: We develop a framework to simultaneously compute the unobservable parameters underlying the structural-parametric models for bankruptcy prediction. More specifically, we compute the unobservable parameters such as, asset value and asset volatility, through learning by embedding in the structural models a neural network that maps the neural network's input space (e.g. companies' observable financial and market data) to the unobservable parameter space. Within such a `neuro-structural' framework, the neural network and the structural model work together as a one unit during the learning phase by providing to each other forward and backward information, respectively, until the weights of the neural network are optimized according to a merit function. Empirical results show that structural models, like the Black-Scholes-Merton and the down-and-out option models, with parameters computed with our approach, perform better than alternative specifications of the structural models, out of sample, in terms of discriminatory power, information content and economic impact. Importantly, they also perform better than a standard neural network, suggesting that the co-joint dynamics between the neural network and the structural model are useful during the learning phase and can improve the prediction performance (and the training efficiency) of neural networks. Finally, our approach provides methodological (and empirical) enhancements over logit specifications such as, [\textit{J. Campbell} et al., ``In search of distress risk'', J. Finance, 63, 2899--2939 (2008)]. There, financial and market data are the inputs, and the output is the probability of bankruptcy whereas our approach includes an intermediary step to obtain the unobservable parameters and subsequently the probability of bankruptcy.Multivariate systemic risk measures and computation by deep learning algorithmshttps://zbmath.org/1530.915922024-04-15T15:10:58.286558Z"Doldi, A."https://zbmath.org/authors/?q=ai:doldi.alessandro"Feng, Y."https://zbmath.org/authors/?q=ai:feng.yichen"Fouque, J.-P."https://zbmath.org/authors/?q=ai:fouque.jean-pierre"Frittelli, M."https://zbmath.org/authors/?q=ai:frittelli.marcoSummary: In this work, we propose deep learning-based algorithms for the computation of systemic shortfall risk measures defined via multivariate utility functions. We discuss the key related theoretical aspects, with a particular focus on the fairness properties of primal optima and associated risk allocations. The algorithms we provide allow for learning primal optimizers, optima for the dual representation and corresponding fair risk allocations. We test our algorithms by comparison to a benchmark model, based on a paired exponential utility function, for which we can provide explicit formulas. We also show evidence of convergence in a case in which explicit formulas are not available.Biomedical data analysis and processing using explainable (XAI) and responsive artificial intelligence (RAI)https://zbmath.org/1530.920032024-04-15T15:10:58.286558ZPublisher's description: The book discusses Explainable (XAI) and Responsive Artificial Intelligence (RAI) for biomedical and healthcare applications. It will discuss the advantages in dealing with big and complex data by using explainable AI concepts in the field of biomedical sciences. The book explains both positive as well as negative findings obtained by explainable AI techniques. It features real time experiences by physicians and medical staff for applied deep learning based solutions. The book will be extremely useful for researchers and practitioners in advancing their studies.
The articles of this volume will be reviewed individually.Deep learning and medical applicationshttps://zbmath.org/1530.920052024-04-15T15:10:58.286558ZPublisher's description: Over the past 40 years, diagnostic medical imaging has undergone remarkable advancements in CT, MRI, and ultrasound technology. Today, the field is experiencing a major paradigm shift, thanks to significant and rapid progress in deep learning techniques. As a result, numerous innovative AI-based programs have been developed to improve image quality and enhance clinical workflows, leading to more efficient and accurate diagnoses.
AI advancements of medical imaging not only address existing unsolved problems but also present new and complex challenges. Solutions to these challenges can improve image quality and reveal new information currently obscured by noise, artifacts, or other signals. Holistic insight is the key to solving these challenges. Such insight may lead to a creative solution only when it is based on a thorough understanding of existing methods and unmet demands.
This book focuses on advanced topics in medical imaging modalities, including CT and ultrasound, with the aim of providing practical applications in the healthcare industry. It strikes a balance between mathematical theory, numerical practice, and clinical applications, offering comprehensive coverage from basic to advanced levels of mathematical theories, deep learning techniques, and algorithm implementation details. Moreover, it provides in-depth insights into the latest advancements in dental cone-beam CT, fetal ultrasound, and bioimpedance, making it an essential resource for professionals seeking to stay up-to-date with the latest developments in the field of medical imaging.
The articles of this volume will be reviewed individually.Clifford algebra multivectors and kernels for melanoma classificationhttps://zbmath.org/1530.920352024-04-15T15:10:58.286558Z"Akar, Mutlu"https://zbmath.org/authors/?q=ai:akar.mutlu"Sirakov, Nikolay M."https://zbmath.org/authors/?q=ai:sirakov.nikolay-metodiev"Mete, Mutlu"https://zbmath.org/authors/?q=ai:mete.mutlu(no abstract)MoTERNN: classifying the mode of cancer evolution using recursive neural networkshttps://zbmath.org/1530.920392024-04-15T15:10:58.286558Z"Edrisi, Mohammadamin"https://zbmath.org/authors/?q=ai:edrisi.mohammadamin"Ogilvie, Huw A."https://zbmath.org/authors/?q=ai:ogilvie.huw-a"Li, Meng"https://zbmath.org/authors/?q=ai:li.meng.2|li.meng.1"Nakhleh, Luay"https://zbmath.org/authors/?q=ai:nakhleh.luaySummary: With the advent of single-cell DNA sequencing, it is now possible to infer the evolutionary history of thousands of tumor cells obtained from a single patient. This evolutionary history, which takes the shape of a tree, reveals the mode of evolution of the specific cancer under study and, in turn, helps with clinical diagnosis, prognosis, and therapeutic treatment. In this study we focus on the question of determining the mode of evolution of tumor cells from their inferred evolutionary history. In particular, we employ recursive neural networks that capture tree structures to classify the evolutionary history of tumor cells into one of four modes -- \textit{linear}, \textit{branching}, \textit{neutral}, and \textit{punctuated}. We trained our model, MoTERNN, using simulated data in a supervised fashion and applied it to a real phylogenetic tree obtained from single-cell DNA sequencing data. MoTERNN is implemented in Python and is publicly available at \url{https://github.com/NakhlehLab/MoTERNN}.
For the entire collection see [Zbl 1525.92003].Counters in Kappa: semantics, simulation, and static analysishttps://zbmath.org/1530.920552024-04-15T15:10:58.286558Z"Boutillier, Pierre"https://zbmath.org/authors/?q=ai:boutillier.pierre"Cristescu, Ioana"https://zbmath.org/authors/?q=ai:cristescu.ioana-domnina"Feret, Jérôme"https://zbmath.org/authors/?q=ai:feret.jeromeSummary: Site-graph rewriting languages, such as Kappa or BNGL, offer parsimonious ways to describe highly combinatorial systems of mechanistic interactions among proteins. These systems may be then simulated efficiently. Yet, the modeling mechanisms that involve counting (a number of phosphorylated sites for instance) require an exponential number of rules in Kappa. In BNGL, updating the set of the potential applications of rules in the current state of the system comes down to the sub-graph isomorphism problem (which is NP-complete).
In this paper, we extend Kappa to deal both parsimoniously and efficiently with counters. We propose a single push-out semantics for Kappa with counters. We show how to compile Kappa with counters into Kappa without counters (without requiring an exponential number of rules). We design a static analysis, based on affine relationships, to identify the meaning of counters and bound their ranges accordingly.
For the entire collection see [Zbl 1408.68010].A novel hybrid CNN and BiGRU-attention based deep learning model for protein function predictionhttps://zbmath.org/1530.920662024-04-15T15:10:58.286558Z"Sharma, Lavkush"https://zbmath.org/authors/?q=ai:sharma.lavkush"Deepak, Akshay"https://zbmath.org/authors/?q=ai:deepak.akshay"Ranjan, Ashish"https://zbmath.org/authors/?q=ai:ranjan.ashish"Krishnasamy, Gopalakrishnan"https://zbmath.org/authors/?q=ai:krishnasamy.gopalakrishnan(no abstract)Predicting pathways for old and new metabolites through clusteringhttps://zbmath.org/1530.920672024-04-15T15:10:58.286558Z"Siddharth, Thiru"https://zbmath.org/authors/?q=ai:siddharth.thiru"Lewis, Nathan E."https://zbmath.org/authors/?q=ai:lewis.nathan-eSummary: The diverse metabolic pathways are fundamental to all living organisms, as they harvest energy, synthesize biomass components, produce molecules to interact with the microenvironment, and neutralize toxins. While the discovery of new metabolites and pathways continues, the prediction of pathways for new metabolites can be challenging. It can take vast amounts of time to elucidate pathways for new metabolites; thus, according to HMDB (Human Metabolome Database), only 60\% of metabolites get assigned to pathways. Here, we present an approach to identify pathways based on metabolite structure. We extracted 201 features from SMILES annotations and identified new metabolites from PubMed abstracts and HMDB. After applying clustering algorithms to both groups of features, we quantified correlations between metabolites, and found the clusters accurately linked 92\% of known metabolites to their respective pathways. Thus, this approach could be valuable for predicting metabolic pathways for new metabolites.Generation and robustness of Boolean networks to model \textit{Clostridium difficile} infectionhttps://zbmath.org/1530.920742024-04-15T15:10:58.286558Z"Travisany, Dante"https://zbmath.org/authors/?q=ai:travisany.dante"Goles, Eric"https://zbmath.org/authors/?q=ai:goles-chacc.eric"Latorre, Mauricio"https://zbmath.org/authors/?q=ai:latorre.mauricio"Cortés, María-Paz"https://zbmath.org/authors/?q=ai:cortes.maria-paz"Maass, Alejandro"https://zbmath.org/authors/?q=ai:maass.alejandro(no abstract)T-cell receptor optimization with reinforcement learning and mutation polices for precision immunotherapyhttps://zbmath.org/1530.920872024-04-15T15:10:58.286558Z"Chen, Ziqi"https://zbmath.org/authors/?q=ai:chen.ziqi"Min, Martin Renqiang"https://zbmath.org/authors/?q=ai:min.martin-renqiang"Guo, Hongyu"https://zbmath.org/authors/?q=ai:guo.hongyu"Cheng, Chao"https://zbmath.org/authors/?q=ai:cheng.chao"Clancy, Trevor"https://zbmath.org/authors/?q=ai:clancy.trevor"Ning, Xia"https://zbmath.org/authors/?q=ai:ning.xiaSummary: T cells monitor the health status of cells by identifying foreign peptides displayed on their surface. T-cell receptors (TCRs), which are protein complexes found on the surface of T cells, are able to bind to these peptides. This process is known as TCR recognition and constitutes a key step for immune response. Optimizing TCR sequences for TCR recognition represents a fundamental step towards the development of personalized treatments to trigger immune responses killing cancerous or virus-infected cells. In this paper, we formulated the search for these optimized TCRs as a reinforcement learning (\texttt{RL}) problem, and presented a framework \texttt{TCRPPO} with a mutation policy using proximal policy optimization. \texttt{TCRPPO} mutates TCRs into effective ones that can recognize given peptides. \texttt{TCRPPO} leverages a reward function that combines the likelihoods of mutated sequences being valid TCRs measured by a new scoring function based on deep autoencoders, with the probabilities of mutated sequences recognizing peptides from a peptide-TCR interaction predictor. We compared \texttt{TCRPPO} with multiple baseline methods and demonstrated that \texttt{TCRPPO} significantly outperforms all the baseline methods to generate positive binding and valid TCRs. These results demonstrate the potential of \texttt{TCRPPO} for both precision immunotherapy and peptide-recognizing TCR motif discovery.
For the entire collection see [Zbl 1524.92002].MTGL-ADMET: a novel multi-task graph learning framework for ADMET prediction enhanced by status-theory and maximum flowhttps://zbmath.org/1530.920882024-04-15T15:10:58.286558Z"Du, Bing-Xue"https://zbmath.org/authors/?q=ai:du.bing-xue"Xu, Yi"https://zbmath.org/authors/?q=ai:xu.yi.1"Yiu, Siu-Ming"https://zbmath.org/authors/?q=ai:yiu.siuming|yiu.siu-ming"Yu, Hui"https://zbmath.org/authors/?q=ai:yu.hui.4|yu.hui.5|yu.hui.3|yu.hui.2"Shi, Jian-Yu"https://zbmath.org/authors/?q=ai:shi.jianyuSummary: It is a vital step to evaluate drug-like compounds in terms of absorption, distribution, metabolism, excretion, and toxicity (ADMET) in drug design. Classical single-task learning based on abundant labels has achieved inspiring progress in predicting individual ADMET endpoints. Multi-task learning (MTL), having the low requirement of endpoint labels, can predict multiple ADMET endpoints simultaneously. Nonetheless, it is still an ongoing issue that the performance of existing MTL-based approaches depends on how appropriate participating tasks are. Furthermore, there is a need to elucidate what substructures are crucial to specific ADMET endpoints. To address these issues, this work constructs a multi-task graph learning framework for predicting multiple ADMET properties of drug-like small molecules (MTGL-ADMET) under a new paradigm of MTL, `one primary, multiple auxiliaries'. It first leverages the status theory and the maximum flow to select appropriate auxiliary tasks of a specific ADMET endpoint task. Then, it designs a novel primary-centered multi-task learning model, which consists of a task-shared atom embedding module, a task-specific molecular embedding module, a primary task-centered gating module, and a multi-task predictor. The comparison with state-of-the-art MTL-based methods demonstrates the superiority of MTGL-ADMET. More elaborate experiments validate its contributions, including the status theory-based auxiliary selection algorithm and the novel MTL architecture. Furthermore, a case study illustrates the interpretability of MTGL-ADMET by indicating crucial substructures w.r.t. the primary task. It's anticipated that this work can boost pharmacokinetic and toxicity analysis in drug discovery. The code and data underlying this article are freely available at \url{https://github.com/dubingxue/MTGL-ADMET}.
For the entire collection see [Zbl 1524.92002].CDGCN: conditional de novo drug generative model using graph convolution networkshttps://zbmath.org/1530.920932024-04-15T15:10:58.286558Z"Mallick, Shikha"https://zbmath.org/authors/?q=ai:mallick.shikha"Bhadra, Sahely"https://zbmath.org/authors/?q=ai:bhadra.sahelySummary: \textit{De novo} drug design is a crucial part of drug discovery which is a highly expensive and slow process. Many deep learning methods have been proposed to automate and accelerate it. However, most of the current state-of-the-art methods are limited to generating novel drugs specific to proteins that already have known drugs or limited to generating molecules which lack certain desirable drug-like properties like high binding affinity or low binding energy. We introduce our graph generative model, CDGCN (conditional \textit{de novo} drug generative model using graph convolution networks), for \textit{de novo} drug generation for novel proteins, which takes as input a protein sequence of amino acids and generates novel molecular structures having desirable drug-like properties. CDGCN generates desirable molecules for a protein using a sequential decoding scheme by learning the distribution of generation paths of its ligands. We show that CDGCN can quickly generate novel and chemically valid drug-like molecules which have a higher binding affinity with their target proteins as compared to the state-of-the-art methods. The best binding energy between a novel protein and its novel drug-like molecules generated by CDGCN was observed to be at least \(-7.3\)\,kcal/mol whereas for the state-of-the-art method it was observed to be \(-6.2\)\,kcal/mol.
\textbf{Availability and implementation:} Code and data are available at \url{https://github.com/mshik/CDGCN}.
For the entire collection see [Zbl 1524.92002].PU-NET deep learning architecture for Gliomas brain tumor segmentation in magnetic resonance imageshttps://zbmath.org/1530.921072024-04-15T15:10:58.286558Z"Azzi, Yamina"https://zbmath.org/authors/?q=ai:azzi.yamina"Moussaoui, Abdelouahab"https://zbmath.org/authors/?q=ai:moussaoui.abdelouahab"Kechadi, Mohand-Tahar"https://zbmath.org/authors/?q=ai:kechadi.mohand-taharSummary: Automatic medical image segmentation is one of the main tasks for many organs and pathology structures delineation. It is also a crucial technique in the posterior clinical examination of brain tumors, like applying radiotherapy or tumor restrictions. Various image segmentation techniques have been proposed and applied to different image types. Recently, it has been shown that the deep learning approach accurately segments images, and its implementation is usually straightforward. In this paper, we proposed a novel approach, called PU-NET, for automatic brain tumor segmentation in multi-modal magnetic resonance images (MRI). We introduced an input processing block to a customized fully convolutional network derived from the U-Net network to handle the multi-modal inputs. We performed experiments over the brain tumor segmentation (BRATS) dataset collected in 2018 and achieved Dice scores of 90.5\%, 82.7\%, and 80.3\% for the whole tumor, tumor core, and enhancing tumor classes, respectively. This study provides promising results compared to the deep learning methods used in this context.Remote heart rate estimation via convolutional neural networks with transformershttps://zbmath.org/1530.921092024-04-15T15:10:58.286558Z"Guo, Zongheng"https://zbmath.org/authors/?q=ai:guo.zongheng"Chen, Huahua"https://zbmath.org/authors/?q=ai:chen.huahua"Lin, Lili"https://zbmath.org/authors/?q=ai:lin.lili"Zhou, Wenhui"https://zbmath.org/authors/?q=ai:zhou.wenhui"Yang, Meng"https://zbmath.org/authors/?q=ai:yang.meng"Ying, Na"https://zbmath.org/authors/?q=ai:ying.na"Guo, Chunsheng"https://zbmath.org/authors/?q=ai:guo.chunshengSummary: Remote photoplethysmography (rPPG) uses subtle color changes in facial videos to estimate heart rate (HR). However, recent methods face challenges in solving remote heart rate estimation tasks, because the color changes in facial skin are very subtle and the pseudo-periodicity of rPPG requires long-distance temporal detection. To address these issues of the rPPG estimation task, we propose a convolution neural network with transformers for rPPG estimation which takes the advantages of convolutions in the locality and transformers in long-range dependencies. Specifically, we first proposed a local feed-forward module following the multi-head self-attention to compensate for the difficulties of transformers in capturing neighboring feature information. Then we add the relative and absolute position encoding to obtain the ordering of the tokens which is the key to capturing the pseudo-periodicity of rPPG. Furthermore, the temporal multi-scale module is proposed to learn the temporal information from different scales. Extensive experimental results demonstrate that our method is superior to the state-of-the-art results on the COHFACE, UBFC-rPPG, PURE, and VIPL-HR databases compared with traditional methods and deep learning-based methods. We also evaluated our method under different conditions on the VIPL-HR database, and the results show that our method is robust to various conditions.DM-Net: a dual-model network for automated biomedical image diagnosishttps://zbmath.org/1530.921182024-04-15T15:10:58.286558Z"Zhou, Xiaogen"https://zbmath.org/authors/?q=ai:zhou.xiaogen"Li, Zhiqiang"https://zbmath.org/authors/?q=ai:li.zhiqiang|li.zhiqiang.1"Tong, Tong"https://zbmath.org/authors/?q=ai:tong.tongSummary: Biomedical image segmentation is an essential task in the computer-aided diagnosis system. An encoder-decoder based on a shallow or deep convolutional neural network (DCNN) is an extensively used framework for biomedical image analysis. To study and rethink the effectiveness of compounding both the shallow and deep networks for the medical image segmentation task, we propose a dual-model CNN architecture, called DM-Net, for biomedical image segmentation. DM-Net is composed of a shallow CNN structure at its left, called L-Net and a deeper CNN structure at its right, named R-Net. The L-Net is proposed to encode low-level contextual information and the R-Net is presented to produce high-level semantic feature maps. Furthermore, a novel crossed-skip connection (CSC) strategy is proposed to transfer information between the two side networks mutually. Extensive experiments demonstrate that our method outperforms representative approaches on three public medical image datasets.
For the entire collection see [Zbl 1524.92002].Two strikes against the phage recombination problemhttps://zbmath.org/1530.921412024-04-15T15:10:58.286558Z"Lafond, Manuel"https://zbmath.org/authors/?q=ai:lafond.manuel"Bergeron, Anne"https://zbmath.org/authors/?q=ai:bergeron.anne"Swenson, Krister M."https://zbmath.org/authors/?q=ai:swenson.krister-mSummary: The recombination problem is inspired by genome rearrangement events that occur in bacteriophage populations. Its goal is to explain the transformation of one bacteriophage population into another using the minimum number of recombinations. Here we show that the combinatorial problem is NP-complete, both when the target population contains only one genome of unbounded length, and when the size of the genomes is bounded by a constant. In the first case, the existence of a minimum solution is shown to be equivalent to a 3D-matching problem, and in the second case, to a satisfiability problem. These results imply that the comparison of bacteriophage populations using recombinations may have to rely on heuristics that exploit biological constraints.
For the entire collection see [Zbl 1525.92003].Graphon mean-field control for cooperative multi-agent reinforcement learninghttps://zbmath.org/1530.930122024-04-15T15:10:58.286558Z"Hu, Yuanquan"https://zbmath.org/authors/?q=ai:hu.yuanquan"Wei, Xiaoli"https://zbmath.org/authors/?q=ai:wei.xiaoli"Yan, Junji"https://zbmath.org/authors/?q=ai:yan.junji"Zhang, Hengxi"https://zbmath.org/authors/?q=ai:zhang.hengxiSummary: The marriage between mean-field theory and reinforcement learning has shown a great capacity to solve large-scale control problems with homogeneous agents. To break the homogeneity restriction of mean-field theory, a recent interest is to introduce graphon theory to the mean-field paradigm. In this paper, we propose a graphon mean-field control (GMFC) framework to approximate cooperative heterogeneous multi-agent reinforcement learning (MARL) with nonuniform interactions and heterogeneous reward functions and state transition functions among agents and show that the approximate order is of \(\mathcal{O}\left(\frac{1}{\sqrt{N}}\right)\), with \(N\) the number of agents. By discretizing the graphon index of GMFC, we further introduce a smaller class of GMFC called block GMFC, which is shown to well approximate cooperative MARL in terms of the value function and the policy. Finally, we design a proximal policy optimization based algorithm for block GMFC that converges to the optimal policy of cooperative MARL. Our empirical studies on several examples demonstrate that our GMFC approach is comparable with the state-of-art MARL algorithms while enjoying better scalability.Deep learning for posture control nonlinear model system and noise identificationhttps://zbmath.org/1530.930702024-04-15T15:10:58.286558Z"Lippi, Vittorio"https://zbmath.org/authors/?q=ai:lippi.vittorio"Mergner, Thomas"https://zbmath.org/authors/?q=ai:mergner.thomas"Maurer, Christoph"https://zbmath.org/authors/?q=ai:maurer.christophSummary: In this work we present a system identification procedure based on convolutional neural networks (CNN) for human posture control models. A usual approach to the study of human posture control consists in the identification of parameters for a control system. In this context, linear models are particularly popular due to the relative simplicity in identifying the required parameters and to analyze the results. Nonlinear models, conversely, are required to predict the real behavior exhibited by human subjects and hence it is desirable to use them in posture control analysis. The use of CNN aims to overcome the heavy computational requirement for the identification of nonlinear models, in order to make the analysis of experimental data less time consuming and, in perspective, to make such analysis feasible in the context of clinical tests. After testing the performance of the CNN on validation and test sets, two examples are presented and discussed from the qualitative point of view: the identification of parameters using data from human experiments and using data of a simulated model with some differences with respect to the one used to build the training set. Some potential implications of the method for humanoid robotics are also discussed.
For the entire collection see [Zbl 1485.93013].Coevolutionary algorithm for multivariable discrete linear time-variant system identificationhttps://zbmath.org/1530.930732024-04-15T15:10:58.286558Z"Robles, Alexander E."https://zbmath.org/authors/?q=ai:robles.alexander-e"Giesbrecht, Mateus"https://zbmath.org/authors/?q=ai:giesbrecht.mateusSummary: A significant part of the works in system identification is focused on time-invariant dynamic systems. However, most of systems in the real applications have nonlinear and time variant behavior. In this paper, we present a multivariable time-variant identification method based on a paradigm in the field of evolutionary algorithms: The coevolutionary algorithm. This new method focuses on the relationship between the fitness of an individual in relation to the fitness of the other individuals (or group of individuals), based on the principle of the selective pressure, that is part of the evolutionary process. A brief comparison between a multivariable deterministic identification method MOESP-VAR and the proposed coevolutionary method is shown. From the results it is possible to notice that the proposed method presents an accuracy higher than the obtained with the deterministic identification method.
For the entire collection see [Zbl 1485.93017].A framework for fault-tolerant control for an interacting and non-interacting level control system using AIhttps://zbmath.org/1530.930862024-04-15T15:10:58.286558Z"Patel, Himanshukumar R."https://zbmath.org/authors/?q=ai:patel.himanshukumar-r"Shah, Vipul A."https://zbmath.org/authors/?q=ai:shah.vipul-aSummary: In chemical and process industries, interacting and non-interacting level control systems are often used for material storage and processing. The level control parameter is very vital for dealing with faults in a system (leak), actuator or sensor. System and actuator faults occurring in a system may decrease the performance or cause instability and unsafe accidents. As observed from practice, when the control performance of the interacting and non-interacting systems decreases due to occurrence of faults, a fault-tolerant control strategy (FTC) is required. This paper presents a framework for passive fault tolerant control (PFTC) using a neural network (NN) and it is designed in order to ensure the stability robustness of the system in the presence of the faults. In fact, FTC is the potential strategy which is justified by its ability to preserve an acceptable performance in the presence of faults and process disturbances. To check the effectiveness of the proposed framework single-tank and two-tank level control experimental setup are used with system and sensor faults. Simulation and experiment results are presented to demonstrate the capability of the proposed framework of PFTC using NN to counteract the effect of the system, sensor and actuator faults.
For the entire collection see [Zbl 1485.93017].Deep Q-learning: a robust control approachhttps://zbmath.org/1530.930872024-04-15T15:10:58.286558Z"Varga, Balázs"https://zbmath.org/authors/?q=ai:varga.balazs"Kulcsár, Balázs"https://zbmath.org/authors/?q=ai:kulcsar.balazs"Chehreghani, Morteza Haghir"https://zbmath.org/authors/?q=ai:chehreghani.morteza-haghirSummary: This work aims at constructing a bridge between robust control theory and reinforcement learning. Although, reinforcement learning has shown admirable results in complex control tasks, the agent's learning behavior is opaque. Meanwhile, system theory has several tools for analyzing and controlling dynamical systems. This article places deep Q-learning is into a control-oriented perspective to study its learning dynamics with well-established techniques from robust control. An uncertain linear time-invariant model is formulated by means of the neural tangent kernel to describe learning. This novel approach allows giving conditions for stability (convergence) of the learning and enables the analysis of the agent's behavior in frequency-domain. The control-oriented approach makes it possible to formulate robust controllers that inject dynamical rewards as control input in the loss function to achieve better convergence properties. Three output-feedback controllers are synthesized: gain scheduling \(\mathscr{H}_2\), dynamical \(\mathscr{H}_\infty\), and fixed-structure \(\mathscr{H}_\infty\) controllers. Compared to traditional deep Q-learning techniques, which involve several heuristics, setting up the learning agent with a control-oriented tuning methodology is more transparent and has well-established literature. The proposed approach does not use a target network and randomized replay memory. The role of the target network is overtaken by the control input, which also exploits the temporal dependency of samples (opposed to a randomized memory buffer). Numerical simulations in different OpenAI Gym environments suggest that the \(\mathscr{H}_\infty\) controlled learning can converge faster and receive higher scores (depending on the environment) compared to the benchmark double deep Q-learning.
{{\copyright} 2022 The Authors. \textit{International Journal of Robust and Nonlinear Control} published by John Wiley \& Sons Ltd.}The effect of delay feedback control on dynamics of a stochastic Internet congestion control modelhttps://zbmath.org/1530.931372024-04-15T15:10:58.286558Z"Yang, Yanling"https://zbmath.org/authors/?q=ai:yang.yanling"Hu, Zhouyu"https://zbmath.org/authors/?q=ai:hu.zhouyu"Zhang, Congqing"https://zbmath.org/authors/?q=ai:zhang.congqing"Wang, Qiubao"https://zbmath.org/authors/?q=ai:wang.qiubaoSummary: This paper investigates a stochastic Internet congestion control model with distributed and constant delays driven by Gaussian white noise. We study the stochastic dynamics of the system at different delay feedback intensities. Firstly, by using center manifold theory and the stochastic averaging method, the system is reduced to the average Itô equation. Secondly, the stochastic bifurcation behavior of the system is investigated by using the Fokker-Planck-Kolmogorov equation corresponding to the average Itô equation. It is found that the stochastic P(D)-bifurcation occurs when the delay feedback intensity reaches the critical value. Finally, numerical simulations are given to validate the effectiveness of the theoretical analysis.Residual neural network-based observer design for continuous stirred tank reactor systemshttps://zbmath.org/1530.931412024-04-15T15:10:58.286558Z"Liu, Shi"https://zbmath.org/authors/?q=ai:liu.shi.4"Chen, Song"https://zbmath.org/authors/?q=ai:chen.song"Chen, Tehuan"https://zbmath.org/authors/?q=ai:chen.tehuan"Ren, Zhigang"https://zbmath.org/authors/?q=ai:ren.zhigangSummary: Continuous stirred tank reactor (CSTR) is a common reactor in the chemical industry. The accurate observation of the concentration conversion rate of the mixture and the internal temperature of the reaction vessel is a prerequisite for obtaining the desired mixture. This paper proposes a novel observer based on residual neural networks for CSTR systems. Firstly, the mathematical model of the CSTR reaction is given, as well as a detailed description of the structure and equations of the residual neural networks and the designed observer. Then the matrix method is used for the nonlinear isolation of the residual neural networks and the theory of quadratic constraints for nonlinear activation functions of the neural networks is applied. Thus, the convergence of the proposed observer is analyzed theoretically in detail. Finally, the numerical simulations are implemented to demonstrate that the proposed residual neural network-based observer can quickly and accurately observe the state changes during the CSTR reaction.Sequential recovery of cyber-physical power systems based on improved Q-learninghttps://zbmath.org/1530.931532024-04-15T15:10:58.286558Z"Li, Jian"https://zbmath.org/authors/?q=ai:li.jian.5"Li, Yiqiang"https://zbmath.org/authors/?q=ai:li.yiqiang.1|li.yiqiang"Su, Qingyu"https://zbmath.org/authors/?q=ai:su.qingyuSummary: Cascading failures are one of the most severe threats to cyber-physical power systems. Most studies explore the cascading failure problem from the attacker's perspective while recovering the system from cascading failures is still lacking. This paper proposes a sequential recovery analysis process built within the framework of the cascading failure model, which considers the coupling mechanism of cyber-physical power systems and cascading failures. Then the improved Q-learning based on candidate room and dynamic factor idea of simulated annealing is employed to achieve faster and more efficient identification of optimal recovery sequence for failed lines under resource-limited conditions. Finally, the load recovery performance of four recovery strategies in the single-layer and double-layer systems are compared. The simulation results prove the effectiveness of the proposed sequential recovery process and the recovery strategy based on improved Q-learning.Power quality 24-hour prediction using differential, deep and statistics machine learning based on weather data in an off-gridhttps://zbmath.org/1530.931602024-04-15T15:10:58.286558Z"Zjavka, Ladislav"https://zbmath.org/authors/?q=ai:zjavka.ladislavSummary: Prediction of power quality (PQ) on a daily basis is inevitable in planning renewable energy (RE) supply and scheduling the assumed power load in smart off-grid autonomous systems. Various combinations of the attached household appliances lead to specific operating states, related to the charge and load switching-time in different out-side conditions. Complexity and irregularities require modelling with the use of Artificial Intelligence (AI) to represent the uncertainty in load transitions and RE power oscillations. These specifics cannot be numerically solved with respect to unexpected states in detached micro-grid systems showing great variability. Recent differential learning, developed by the author, using a novel designed neuro-computing approach, enables one to model high non-linear and indefinable chaotic physical systems. The optimal training periods of day-set records were initially pre-assessed, based on AI input-output statistics. This model initialization allows operable day-ahead PQ-predictions in processing the last 24-hour series in one sequence. The proposed 2-level PQ-management evaluates initial load scheduling plans, based on available RE and storage sources. System efficiency and failure-free operations are planned considering the first estimate of its day-ahead PVP supply and secondary PQ verification of the provided load utilization schemes, under various state charges and RE production limits. This is a novelty with a notable incremental improvement in the published combinatorial optimization algorithms, only scheduling applicable load components, and reassessing the allowable power-day resources. Off-grid optimal operations can be determined and regulated by an adequate early morning PQ evaluation in RE utilization. A C++ parametric software, using differential learning to evolve PQ-models, historical PQ \& meteo-data sets are at disposal to enable additional comparisons with the presented models.Nonlinear control using human behavior learninghttps://zbmath.org/1530.931652024-04-15T15:10:58.286558Z"Perrusquía, Adolfo"https://zbmath.org/authors/?q=ai:perrusquia.adolfo"Yu, Wen"https://zbmath.org/authors/?q=ai:yu.wen"Li, Xiaoou"https://zbmath.org/authors/?q=ai:li.xiaoouSummary: In this paper, we discuss a human behavior learning approach for nonlinear systems control. We use several cognitive models and human skills to model and accelerate the learning process. A neural reinforcement learning algorithm is applied as main cognitive model. A persistent exciting signal and experience replay methods are proposed to improve learning accuracy and overcome the sensitivity problem of the human actions. The stability and convergence of the neural network based reinforcement learning is discussed. Simulations results verify the approach with two benchmark control problems.A new neural network feature importance method: application to mobile robots controllers gain tuninghttps://zbmath.org/1530.931702024-04-15T15:10:58.286558Z"Hill, Ashley"https://zbmath.org/authors/?q=ai:hill.ashley"Lucet, Eric"https://zbmath.org/authors/?q=ai:lucet.eric"Lenain, Roland"https://zbmath.org/authors/?q=ai:lenain.rolandSummary: This paper proposes a new approach for feature importance of neural networks and subsequently a methodology using the novel feature importance to determine useful sensor information in high performance controllers, using a trained neural network that predicts the quasi-optimal gain in real time. The neural network is trained using the covariance matrix adaptation evolution strategy (CMA-ES) algorithm, in order to lower a given objective function. The important sensor information for robotic control are determined using the described methodology. Then a proposed improvement to the tested control law is given, and compared with the neural network's gain prediction method for real time gain tuning. As a results, crucial information about the importance of a given sensory information for robotic control is determined, and shown to improve the performance of existing controllers.
For the entire collection see [Zbl 1485.93013].Reinforcement learning-based saturated adaptive robust output-feedback funnel control of surface vessels in different weather conditionshttps://zbmath.org/1530.931892024-04-15T15:10:58.286558Z"Elhaki, Omid"https://zbmath.org/authors/?q=ai:elhaki.omid"Shojaei, Khoshnam"https://zbmath.org/authors/?q=ai:shojaei.khoshnam"Moghtaderizadeh, Iman"https://zbmath.org/authors/?q=ai:moghtaderizadeh.iman"Sajadian, Seyed Jalal"https://zbmath.org/authors/?q=ai:sajadian.seyed-jalalSummary: This article tackles the problem of saturated adaptive robust actor-critic learning PID tracking control design guaranteeing a prescribed funnel performance for ships with multiple dead bands in which the ship's velocities/accelerations and dynamic parameters are unknown and time-variant subject to the availability of external disturbances. The controller is proposed by integrating an observer, adaptive actor-critic multi-layer neural networks, generalized saturation functions, the prescribed performance funnel control, an adaptive robust controller and multiple dead bands. The observer calculates the estimation of ship's velocities/accelerations, in which the peaking phenomenon is prevented by limiting the observer signals. Within the structure of adaptive actor-critic design, adaptive multi-layer neural networks are exerted, which counteracts against ship's time-variant uncertainties and the actuator saturation nonlinearity. In order to reduce the likelihood of actuator saturation well, generalized saturation functions are taken into account. To realize prespecified transient and steady-state performance of the tracking errors, the prescribed performance control is applied. With the purpose of avoiding the corner cutting to increase the trajectory tracking accuracy, curvature of the circular trajectories is calculated and the angle of arc is compensated. An adaptive robust controller is utilized to resist against external disturbances, and a scheme of multiple dead bands is devised in this paper to protect the actuator system in heavy seas.Enhancing train position perception through AI-driven multi-source information fusionhttps://zbmath.org/1530.932112024-04-15T15:10:58.286558Z"Song, Haifeng"https://zbmath.org/authors/?q=ai:song.haifeng"Sun, Zheyu"https://zbmath.org/authors/?q=ai:sun.zheyu"Wang, Hongwei"https://zbmath.org/authors/?q=ai:wang.hongwei.5"Qu, Tianwei"https://zbmath.org/authors/?q=ai:qu.tianwei"Zhang, Zixuan"https://zbmath.org/authors/?q=ai:zhang.zixuan"Dong, Hairong"https://zbmath.org/authors/?q=ai:dong.hairong(no abstract)Deep reinforcement learning based active disturbance rejection load frequency control of multi-area interconnected power systems with renewable energyhttps://zbmath.org/1530.933042024-04-15T15:10:58.286558Z"Zheng, Yuemin"https://zbmath.org/authors/?q=ai:zheng.yuemin"Tao, Jin"https://zbmath.org/authors/?q=ai:tao.jin.1"Sun, Qinglin"https://zbmath.org/authors/?q=ai:sun.qinglin"Sun, Hao"https://zbmath.org/authors/?q=ai:sun.hao.5"Chen, Zengqiang"https://zbmath.org/authors/?q=ai:chen.zengqiang"Sun, Mingwei"https://zbmath.org/authors/?q=ai:sun.mingweiSummary: The use of renewable energy to replace traditional coal, oil and natural gas for power generation is of great significance to the alleviation of environmental pollution and resource depletion. As the core of automatic generation control (AGC), load frequency control (LFC) is of great significance to the stable operation of the power system. However, adding renewable energy sources such as wind turbines and solar energy will bring unstable factors to the frequency response, while frequency fluctuations will reduce the power quality. To minimize the adverse effects caused by renewable energy, the linear active disturbance rejection control (LADRC) based on the soft actor-critic (SAC) algorithm is designed. Through the ability of LADRC to eliminate unknown disturbances and the decision-making ability of the SAC algorithm, an intelligent LFC controller is applied to a two-area interconnected power system with a solar thermal power plant (STPP) and a four-area interconnected power system with wind turbine generator (WTG), photovoltaic (PV) cells and hydro turbine. The simulation results are compared with that of the PID, MPC, and conventional LADRC controllers, highlighting the effectiveness of the proposed method.Monitoring of perception systems: deterministic, probabilistic, and learning-based fault detection and identificationhttps://zbmath.org/1530.933082024-04-15T15:10:58.286558Z"Antonante, Pasquale"https://zbmath.org/authors/?q=ai:antonante.pasquale"Nilsen, Heath G."https://zbmath.org/authors/?q=ai:nilsen.heath-g"Carlone, Luca"https://zbmath.org/authors/?q=ai:carlone.lucaSummary: This paper investigates runtime monitoring of perception systems. Perception is a critical component of high-integrity applications of robotics and autonomous systems, such as self-driving cars. In these applications, failure of perception systems may put human life at risk, and a broad adoption of these technologies requires the development of methodologies to guarantee and monitor safe operation. Despite the paramount importance of perception, currently there is no formal approach for system-level perception monitoring. In this paper, we formalize the problem of runtime fault detection and identification in perception systems and present a framework to model diagnostic information using a \textit{diagnostic graph}. We then provide a set of deterministic, probabilistic, and learning-based algorithms that use diagnostic graphs to perform fault detection and identification. Moreover, we investigate fundamental limits and provide deterministic and probabilistic guarantees on the fault detection and identification results. We conclude the paper with an extensive experimental evaluation, which recreates several realistic failure modes in the LGSVL open-source autonomous driving simulator, and applies the proposed system monitors to a state-of-the-art autonomous driving software stack (Baidu's Apollo Auto). The results show that the proposed system monitors outperform baselines, have the potential of preventing accidents in realistic autonomous driving scenarios, and incur a negligible computational overhead.Improving measurement accuracy of indoor positioning system of a Mecanum wheeled mobile robot using Monte Carlo-Latin hypercube sampling based machine learning algorithmhttps://zbmath.org/1530.933092024-04-15T15:10:58.286558Z"Bayar, Gokhan"https://zbmath.org/authors/?q=ai:bayar.gokhan"Hambarci, Goktug"https://zbmath.org/authors/?q=ai:hambarci.goktugSummary: In this study, an efficient ultra-wideband technology based indoor positioning system is developed to improve the measurement accuracy of a mecanum wheeled mobile robot. Data processing structure of the system is created using Monte Carlo-latin hypercube sampling based machine learning algorithm. Monte Carlo-latin hypercube sampling method can be used to perform the position estimation since it enables the range of each variable is fully accessible. This makes the algorithm outputs more accurate and reliable and thus increases correctness in measurements. An experimental setup including hardware, software and mathematical model is developed. A number of experiments are conducted to validate the indoor positioning system proposed. Efficiency, accuracy and precision of methodology are also tested in the experimental studies. The adaptation of the algorithm in a real system and the field tests are also conducted using a four-mecanum-wheeled mobile robot. The experimental studies show that the position estimation is improved by more than 20\% using the proposed algorithm compared to the methods presented in the literature.Sim-to-real transfer with incremental environment complexity for reinforcement learning of depth-based robot navigationhttps://zbmath.org/1530.933122024-04-15T15:10:58.286558Z"Chaffre, Thomas"https://zbmath.org/authors/?q=ai:chaffre.thomas"Moras, Julien"https://zbmath.org/authors/?q=ai:moras.julien"Chan-Hon-Tong, Adrien"https://zbmath.org/authors/?q=ai:chan-hon-tong.adrien"Marzat, Julien"https://zbmath.org/authors/?q=ai:marzat.julienSummary: Transferring learning-based models to the real world remains one of the hardest problems in model-free control theory. Due to the cost of data collection on a real robot and the limited sample efficiency of deep reinforcement learning algorithms, models are usually trained in a simulator which theoretically provides an infinite amount of data. Despite offering unbounded trial and error runs, the reality gap between simulation and the physical world brings little guarantee about the policy behavior in real operation. Depending on the problem, expensive real fine-tuning and/or a complex domain randomization strategy may be required to produce a relevant policy. In this paper, a soft-actor critic (SAC) training strategy using incremental environment complexity is proposed to drastically reduce the need for additional training in the real world. The application addressed is depth-based mapless navigation, where a mobile robot should reach a given waypoint in a cluttered environment with no prior mapping information. Experimental results in simulated and real environments are presented to assess quantitatively the efficiency of the proposed approach, which demonstrated a success rate twice higher than a naive strategy.
For the entire collection see [Zbl 1485.93013].Structured learning of rigid-body dynamics: a survey and unified view from a robotics perspectivehttps://zbmath.org/1530.933252024-04-15T15:10:58.286558Z"Geist, A. René"https://zbmath.org/authors/?q=ai:geist.a-rene"Trimpe, Sebastian"https://zbmath.org/authors/?q=ai:trimpe.sebastianSummary: Accurate models of mechanical system dynamics are often critical for model-based control and reinforcement learning. Fully data-driven dynamics models promise to ease the process of modeling and analysis, but require considerable amounts of data for training and often do not generalize well to unseen parts of the state space. Combining data-driven modeling with prior analytical knowledge is an attractive alternative as the inclusion of structural knowledge into a regression model improves the model's data efficiency and physical integrity. In this article, we survey supervised regression models that combine rigid-body mechanics with data-driven modeling techniques. We analyze the different latent functions (such as kinetic energy or dissipative forces) and operators (such as differential operators and projection matrices) underlying common descriptions of rigid-body mechanics. Based on this analysis, we provide a unified view on the combination of data-driven regression models, such as neural networks and Gaussian processes, with analytical model priors. Furthermore, we review and discuss key techniques for designing structured models such as automatic differentiation.
{\copyright} 2021 The Authors. \textit{GAMM - Mitteilungen} published by Wiley-VCH GmbH.Multi-task safe reinforcement learning for navigating intersections in dense traffichttps://zbmath.org/1530.933392024-04-15T15:10:58.286558Z"Liu, Yuqi"https://zbmath.org/authors/?q=ai:liu.yuqi"Gao, Yinfeng"https://zbmath.org/authors/?q=ai:gao.yinfeng"Zhang, Qichao"https://zbmath.org/authors/?q=ai:zhang.qichao"Ding, Dawei"https://zbmath.org/authors/?q=ai:ding.dawei"Zhao, Dongbin"https://zbmath.org/authors/?q=ai:zhao.dongbinSummary: Multi-task intersection navigation, which includes unprotected turning left, turning right, and going straight in heavy traffic, remains a difficult task for autonomous vehicles. For the human driver, negotiation skills with other interactive vehicles are the key to guaranteeing safety and efficiency. However, it is hard to balance the safety and efficiency of the autonomous vehicle for multi-task intersection navigation. In this paper, we formulate a multi-task safe reinforcement learning framework with social attention to improve the safety and efficiency when interacting with other traffic participants. Specifically, the social attention module is used to focus on the states of negotiation vehicles. In addition, a safety layer is added to the multi-task reinforcement learning framework to guarantee safe negotiation. We deploy experiments in the simulators SUMO, which has abundant traffic flows, and CARLA, which has high-fidelity vehicle models. Both show that the proposed algorithm improves safety while maintaining stable traffic efficiency for the multi-task intersection navigation problem. More details and demonstrations are available at \url{https://github.com/liuyuqi123/SAT}.An inertial neural network approach for loco-manipulation trajectory tracking of mobile robot with redundant manipulatorhttps://zbmath.org/1530.933582024-04-15T15:10:58.286558Z"Xu, Chentao"https://zbmath.org/authors/?q=ai:xu.chentao"Wang, Miao"https://zbmath.org/authors/?q=ai:wang.miao"Chi, Guoyi"https://zbmath.org/authors/?q=ai:chi.guoyi"Liu, Qingshan"https://zbmath.org/authors/?q=ai:liu.qingshanConsider the combined control and optimization of a mobile robot, consisting of a mobile platform and the manipulator. The main objects of the paper are: i) design of a trajectory tracking model based on the loco-manipulability of the mobile robot, ii) the construction of a control law, having an improved performance compared with known ones. Here, the objective function of the resulting optimization problem is based on the loco-manipulability and kinetic energy of the manipulator and mobile platform. Constrains are given for the velocity in \(z\)-axis of the mobile platform, which can move only on the horizontal plane. iii) For solving the resulting augmented Lagrangian primal-dual optimization problem, a neural network approach is applied. Moreover, the convergence behavior of the method is evaluated by simulation experiments.
Reviewer: Kurt Marti (München)Sailboat navigation control system based on spiking neural networkshttps://zbmath.org/1530.933632024-04-15T15:10:58.286558Z"Giraldo, Nelson Santiago"https://zbmath.org/authors/?q=ai:giraldo.nelson-santiago"Isaza, Sebastián"https://zbmath.org/authors/?q=ai:isaza.sebastian"Velásquez, Ricardo Andrés"https://zbmath.org/authors/?q=ai:velasquez.ricardo-andres(no abstract)Deep reinforcement learning with reference system to handle constraints for energy-efficient train controlhttps://zbmath.org/1530.933652024-04-15T15:10:58.286558Z"Shang, Mengying"https://zbmath.org/authors/?q=ai:shang.mengying"Zhou, Yonghua"https://zbmath.org/authors/?q=ai:zhou.yonghua"Fujita, Hamido"https://zbmath.org/authors/?q=ai:fujita.hamidoSummary: Train energy-efficient control involves complicated optimization processes subject to constraints such as speed, time, position and comfort requirements. Conventional optimization techniques are not apt at accumulating numerous solution instances into decision intelligence by learning for consecutively confronted new problems. Deep reinforcement learning (DRL), which can directly output control decisions based on current states, has shown great potentials for next-generation intelligent control. However, if the DRL is directly applied to energy-efficient train control, the received results are almost unsatisfactory. The reason lies in that the agent may get into confusion about how to trade off those constraints, and spend great computational time performing a large number of meaningless explorations. This article attempts to propose an approach of DRL with a reference system (DRL-RS) for proactive constraint handling, where the reference system deals with checking and correcting the agent's learning progresses to avoid stepping farther and farther onto the erroneous road. The proposed approach is evaluated by the numerical experiments on train control in metro lines. The experimental results demonstrate that the DRL-RS can achieve faster learning convergence, compared with the directly applied DRL. Furthermore, it is possible to reduce more energy consumption than the commonly used genetic algorithm.ARAIL: learning to rank from incomplete demonstrationshttps://zbmath.org/1530.933662024-04-15T15:10:58.286558Z"Xu, Dayong"https://zbmath.org/authors/?q=ai:xu.dayong"Zhu, Fei"https://zbmath.org/authors/?q=ai:zhu.fei"Liu, Quan"https://zbmath.org/authors/?q=ai:liu.quan"Zhao, Peiyao"https://zbmath.org/authors/?q=ai:zhao.peiyaoSummary: Generative adversarial imitation learning (GAIL) has been successfully applied to imitation learning in control tasks. However, most GAIL-like approaches require complete and high-quality demonstrations that are scarcely available in practice, which leads to unsatisfactory performances. Researches have proposed algorithms for incomplete demonstrations, which, however, are supposed to be effective only when exceptionally high-quality demonstrations are provided. To solve the problem, the action-rank adversarial imitation learning (ARAIL) algorithm is introduced to target the issue of incomplete demonstrations. By reconstructing the standard GAIL framework and introducing the ranker model, ARAIL reshapes the reward function from the discriminator and auxiliary information from the ranker. The primary insight is that the ranker makes a better assessment of missing actions, which in turn helps to learn a better policy. We empirically compare our approach with SOTA algorithms on Atari and Mujoco platforms with imitation learning benchmarks, demonstrating that ARAIL improves both performance and robustness on various levels of incompleteness of actions in demonstrations.Efficient construction of neural networks Lyapunov functions with domain of attraction maximizationhttps://zbmath.org/1530.934332024-04-15T15:10:58.286558Z"Bocquillon, Benjamin"https://zbmath.org/authors/?q=ai:bocquillon.benjamin"Feyel, Philippe"https://zbmath.org/authors/?q=ai:feyel.philippe"Sandou, Guillaume"https://zbmath.org/authors/?q=ai:sandou.guillaume"Rodriguez-Ayerbe, Pedro"https://zbmath.org/authors/?q=ai:rodriguez-ayerbe.pedro.1|rodriguez-ayerbe.pedroSummary: This work deals with a new method for computing Lyapunov functions represented by neural networks for autonomous nonlinear systems. Based on the Lyapunov theory and the notion of domain of attraction, we propose an optimization method for determining a Lyapunov function modelled by a neural network while maximizing the domain of attraction. The potential of the proposed method is demonstrated by simulation examples.
For the entire collection see [Zbl 1485.93013].Advanced Boolean techniques. Selected papers from the 15th international workshop on Boolean problems, IWSBP, Bremen, Germany, September 22--23, 2022https://zbmath.org/1530.940042024-04-15T15:10:58.286558ZPublisher's description: This book describes recent findings in the domain of Boolean logic and Boolean algebra, covering application domains in circuit and system design, but also basic research in mathematics and theoretical computer science. Content includes invited chapters and a selection of the best papers presented at the 15th annual International Workshop on Boolean Problems.
The articles of mathematical interest will be reviewed individually. For the preceding workshop see [Zbl 1470.94002].Committed-format AND protocol using only random cutshttps://zbmath.org/1530.940142024-04-15T15:10:58.286558Z"Abe, Yuta"https://zbmath.org/authors/?q=ai:abe.yuta"Mizuki, Takaaki"https://zbmath.org/authors/?q=ai:mizuki.takaaki"Sone, Hideaki"https://zbmath.org/authors/?q=ai:sone.hideaki(no abstract)Protecting the most significant bits in scalar multiplication algorithmshttps://zbmath.org/1530.940182024-04-15T15:10:58.286558Z"Alpirez Bock, Estuardo"https://zbmath.org/authors/?q=ai:alpirez-bock.estuardo"Chmielewski, Lukasz"https://zbmath.org/authors/?q=ai:chmielewski.lukasz"Miteloudi, Konstantina"https://zbmath.org/authors/?q=ai:miteloudi.konstantinaSummary: The Montgomery Ladder is widely used for implementing the scalar multiplication in elliptic curve cryptographic designs. This algorithm is efficient and provides a natural robustness against (simple) side-channel attacks. Previous works however showed that implementations of the Montgomery Ladder using Lopez-Dahab projective coordinates easily leak the value of the most significant bits of the secret scalar, which led to a full key recovery in an attack known as \textit{LadderLeak} [\textit{D. F. Aranha} et al., in: CCS '20: Proceedings of the 2020 ACM SIGSAC conference on computer and communications security, October 2020. New York, NY: Association for Computing Machinery (ACM). 225--242 (2020; \url{doi.org/10.1145/3372297.3417268})]. In light of such leakage, we analyse further popular methods for implementing the Montgomery Ladder. We first consider open source software implementations of the X25519 protocol which implement the Montgomery Ladder based on the ladderstep algorithm from \textit{M. Düll} et al. [Des. Codes Cryptography 77, No. 2--3, 493--514 (2015; Zbl 1327.94042)]. We confirm via power measurements that these implementations also easily leak the most significant scalar bits, even when implementing Z-coordinate randomisations. We thus propose simple modifications of the algorithm and its handling of the most significant bits and show the effectiveness of our modifications via experimental results. Particularly, our re-designs of the algorithm do not incurring significant efficiency penalties. As a second case study, we consider open source hardware implementations of the Montgomery Ladder based on the complete addition formulas for prime order elliptic curves, where we observe the exact same leakage. As we explain, the most significant bits in implementations of the complete addition formulas can be protected in an analogous way as we do for Curve25519 in our first case study.
For the entire collection see [Zbl 1516.68007].Weighted oblivious RAM, with applications to searchable symmetric encryptionhttps://zbmath.org/1530.940202024-04-15T15:10:58.286558Z"Assouline, Léonard"https://zbmath.org/authors/?q=ai:assouline.leonard"Minaud, Brice"https://zbmath.org/authors/?q=ai:minaud.briceSummary: Existing Oblivious RAM protocols do not support the storage of data items of variable size in a non-trivial way. While the study of ORAM for items of variable size is of interest in and of itself, it is also motivated by the need for more performant and more secure Searchable Symmetric Encryption (SSE) schemes.
In this article, we introduce the notion of weighted ORAM, which supports the storage of blocks of different sizes. We introduce a framework to build efficient weighted ORAM schemes, based on an underlying standard ORAM satisfying a certain suitability criterion. This criterion is fulfilled by various Tree ORAM schemes, including Simple ORAM and Path ORAM. We deduce several instantiations of weighted ORAM, with very little overhead compared to standard ORAM. As a direct application, we obtain efficient SSE constructions with attractive security properties.
For the entire collection see [Zbl 1528.94002].BBB security for 5-round even-Mansour-based key-alternating Feistel ciphershttps://zbmath.org/1530.940222024-04-15T15:10:58.286558Z"Bhattacharjee, Arghya"https://zbmath.org/authors/?q=ai:bhattacharjee.arghya"Bhaumik, Ritam"https://zbmath.org/authors/?q=ai:bhaumik.ritam"Dutta, Avijit"https://zbmath.org/authors/?q=ai:dutta.avijit"Nandi, Mridul"https://zbmath.org/authors/?q=ai:nandi.mridul"Raychaudhuri, Anik"https://zbmath.org/authors/?q=ai:raychaudhuri.anikSummary: In this paper, we study the security of the Key-Alternating Feistel (KAF) ciphers, a class of key alternating ciphers with the Feistel structure, where each round of the cipher is instantiated with \(n\)-bit public round permutation \(P_i\), namely the \(i\)-th round of the cipher maps
\[
(X_L, X_R) \mapsto (X_R, P_i(X_R \oplus K_i) \oplus K_i \oplus X_L).
\]
We have shown that our 5 round construction with independent round permutations and independent round keys achieves \(2n/3\)-bit security in the random permutation model, i.e., the setting where the adversary is allowed to make forward and inverse queries to the round permutations in a black box way.Oblivious transfer with constant computational overheadhttps://zbmath.org/1530.940232024-04-15T15:10:58.286558Z"Boyle, Elette"https://zbmath.org/authors/?q=ai:boyle.elette"Couteau, Geoffroy"https://zbmath.org/authors/?q=ai:couteau.geoffroy"Gilboa, Niv"https://zbmath.org/authors/?q=ai:gilboa.niv"Ishai, Yuval"https://zbmath.org/authors/?q=ai:ishai.yuval"Kohl, Lisa"https://zbmath.org/authors/?q=ai:kohl.lisa"Resch, Nicolas"https://zbmath.org/authors/?q=ai:resch.nicolas"Scholl, Peter"https://zbmath.org/authors/?q=ai:scholl.peterSummary: The computational overhead of a cryptographic task is the asymptotic ratio between the computational cost of securely realizing the task and that of realizing the task with no security at all.
\textit{Y. Ishai} et al. [in: Proceedings of the 40th annual ACM symposium on theory of computing, STOC 2008. Victoria, Canada, May 17--20, 2008. New York, NY: Association for Computing Machinery (ACM). 433--442 (2008; Zbl 1231.94050)] showed that secure two-party computation of Boolean circuits can be realized with constant computational overhead, independent of the desired level of security, assuming the existence of an oblivious transfer (OT) protocol and a local pseudorandom generator (PRG). However, this only applies to the case of semi-honest parties. A central open question in the area is the possibility of a similar result for malicious parties. This question is open even for the simpler task of securely realizing many instances of a constant-size function, such as OT of bits.
We settle the question in the affirmative for the case of OT, assuming: (1) a standard OT protocol, (2) a slightly stronger ``correlation-robust'' variant of a local PRG, and (3) a standard sparse variant of the Learning Parity with Noise (LPN) assumption. An optimized version of our construction requires fewer than 100 bit operations per party per bit-OT. For 128-bit security, this improves over the best previous protocols by 1--2 orders of magnitude.
We achieve this by constructing a constant-overhead pseudorandom correlation generator (PCG) for the bit-OT correlation. Such a PCG generates \(N\) pseudorandom instances of bit-OT by locally expanding short, correlated seeds. As a result, we get an end-to-end protocol for generating \(N\) pseudorandom instances of bit-OT with \(o(N)\) communication, \(O(N)\) computation, and security that scales sub-exponentially with \(N\).
Finally, we present applications of our main result to realizing other secure computation tasks with constant computational overhead. These include protocols for general circuits with a relaxed notion of security against malicious parties, protocols for realizing \(N\) instances of natural constant-size functions, and reducing the main open question to a potentially simpler question about fault-tolerant computation.
For the entire collection see [Zbl 1528.94002].Quantum time/memory/data tradeoff attackshttps://zbmath.org/1530.940272024-04-15T15:10:58.286558Z"Dunkelman, Orr"https://zbmath.org/authors/?q=ai:dunkelman.orr"Keller, Nathan"https://zbmath.org/authors/?q=ai:keller.nathan"Ronen, Eyal"https://zbmath.org/authors/?q=ai:ronen.eyal"Shamir, Adi"https://zbmath.org/authors/?q=ai:shamir.adiSummary: One of the most celebrated and useful cryptanalytic algorithms is Hellman's time/memory tradeoff (and its Rainbow Table variant), which can be used to invert random-looking functions with domains of size \(N\) with time and space complexities satisfying \(TM^2=N^2\). In this paper we develop new upper bounds on their performance in the quantum setting. As a search problem, one can always apply to it the standard Grover's algorithm, but this algorithm does not benefit from the possible availability of a large memory in which one can store auxiliary advice obtained during a free preprocessing stage. In [\textit{K. -M. Chung} et al., FOCS 2020, 673--684 (2020; \url{doi: 10.1109/FOCS46700.2020.00068})] it was rigorously shown that for memory size bounded by \(M \leq O(\sqrt{N})\), even quantum advice cannot yield an attack which is better than Grover's algorithm. Our main result complements this lower bound by showing that in the standard Quantum Accessible Classical Memory (QACM) model of computation, we can improve Hellman's tradeoff curve to \(T^{4/3}M^2=N^2\). When we generalize the cryptanalytic problem to a time/memory/data tradeoff attack (in which one has to invert \(f\) for at least one of \(D\) given values), we get the generalized curve \(T^{4/3}M^2D^2=N^2\). A typical point on this curve is \(D=N^{0.2}\), \(M=N^{0.6}\), and \(T=N^{0.3}\), whose time is strictly lower than both Grover's algorithm (which requires \(T=N^{0.4}\) in this generalized search variant) and the classical Hellman algorithm (which requires \(T=N^{0.4}\) for these \(D\) and \(M\)).How to compress encrypted datahttps://zbmath.org/1530.940292024-04-15T15:10:58.286558Z"Fleischhacker, Nils"https://zbmath.org/authors/?q=ai:fleischhacker.nils"Larsen, Kasper Green"https://zbmath.org/authors/?q=ai:larsen.kasper-green"Simkin, Mark"https://zbmath.org/authors/?q=ai:simkin.markSummary: We study the task of obliviously compressing a vector comprised of \(n\) ciphertexts of size \(\xi\) bits each, where at most \(t\) of the corresponding plaintexts are non-zero. This problem commonly features in applications involving encrypted outsourced storages, such as searchable encryption or oblivious message retrieval. We present two new algorithms with provable worst-case guarantees, solving this problem by using only homomorphic additions and multiplications by constants. Both of our new constructions improve upon the state of the art asymptotically and concretely.
Our first construction, based on sparse polynomials, is perfectly correct and the first to achieve an asymptotically optimal compression rate by compressing the input vector into \(\mathcal{O}({t \xi })\) bits. Compression can be performed homomorphically by performing \(\mathcal{O}({n \log n})\) homomorphic additions and multiplications by constants. The main drawback of this construction is a decoding complexity of \(\varOmega (\sqrt{n})\).
Our second construction is based on a novel variant of invertible bloom lookup tables and is correct with probability \(1-2^{-\kappa } \). It has a slightly worse compression rate compared to our first construction as it compresses the input vector into \(\mathcal{O}({\xi \kappa t /\log t})\) bits, where \(\kappa \ge \log t\). In exchange, both compression and decompression of this construction are highly efficient. The compression complexity is dominated by \(\mathcal{O}({n \kappa /\log t})\) homomorphic additions and multiplications by constants. The decompression complexity is dominated by \(\mathcal{O}({\kappa t /\log t})\) decryption operations and equally many inversions of a pseudorandom permutation.
For the entire collection see [Zbl 1528.94002].Light but tight: lightweight composition of serialized S-boxes with diffusion layers for strong ciphershttps://zbmath.org/1530.940412024-04-15T15:10:58.286558Z"Sadhukhan, Rajat"https://zbmath.org/authors/?q=ai:sadhukhan.rajat"Chakraborty, Anirban"https://zbmath.org/authors/?q=ai:chakraborty.anirban"Datta, Nilanjan"https://zbmath.org/authors/?q=ai:datta.nilanjan"Patranabis, Sikhar"https://zbmath.org/authors/?q=ai:patranabis.sikhar"Mukhopadhyay, Debdeep"https://zbmath.org/authors/?q=ai:mukhopadhyay.debdeepSummary: The widespread advent of the Internet-of-Things has motivated new design strategies for lightweight block ciphers. In particular, security against traditional cryptanalysis should ideally be complemented by resistance to side-channel attacks, while adhering to low area and power requirements. \textit{A. Ghoshal} et al. [IACR Trans. Symmetric Cryptol. 2018, No. 3, 311--334 (2018; \url{doi:10.13154/tosc.v2018.i3.311-334})] proposed a dedicated design strategy based upon Cellular Automata (CA) for S-Boxes that are amenable to side-channel secure threshold implementations. However, CA-based S-Boxes have some limitations concerning the absence of BOGI properties and low branch numbers making them vulnerable to classical cryptanalysis attacks. In this paper, we address the vulnerabilities of these weak S-Boxes by complementing them with an ultra-lightweight linear layer and subsequently building (Light but Tight) \textsf{LbT} -- the area-efficient and side-channel resilient family of block ciphers. This super-optimal cellular automata (CA)-rule-based S-Box layer is appropriately complemented with a linear layer consisting of shuffle cells and matrix multiplication with an ultra-lightweight almost-MDS matrix with only 6-XOR gates. This ensures high diffusion at the cost of a minimal area overhead. Hence, we show that these vulnerable S-Boxes are not weak but when complemented appropriately with proper linear layer can lead to cryptographically strong as well as lightweight cipher design. Overall, the TI-protected circuit of \textsf{LbT} requires an area footprint of only 3063 GE, which is \(12\%\) lower than any first-order side-channel protected implementation among all of the existing lightweight block ciphers. Finally, we illustrate that \textsf{LbT}-64-128 obtains a reasonable throughput when compared to other lightweight block ciphers.
For the entire collection see [Zbl 1516.68007].Actively revealing card attack on card-based protocolshttps://zbmath.org/1530.940452024-04-15T15:10:58.286558Z"Takashima, Ken"https://zbmath.org/authors/?q=ai:takashima.ken"Miyahara, Daiki"https://zbmath.org/authors/?q=ai:miyahara.daiki"Mizuki, Takaaki"https://zbmath.org/authors/?q=ai:mizuki.takaaki"Sone, Hideaki"https://zbmath.org/authors/?q=ai:sone.hideaki(no abstract)Worst-case subexponential attacks on PRGs of constant degree or constant localityhttps://zbmath.org/1530.940462024-04-15T15:10:58.286558Z"Ünal, Akın"https://zbmath.org/authors/?q=ai:unal.akinSummary: In this work, we will give new attacks on the pseudorandomness of algebraic pseudorandom number generators (PRGs) of polynomial stretch. Our algorithms apply to a broad class of PRGs and are in the case of general local PRGs faster than currently known attacks. At the same time, in contrast to most algebraic attacks, subexponential time and space bounds will be proven for our attacks without making any assumptions of the PRGs or assuming any further conjectures. Therefore, we yield in this text the first subexponential distinguishing attacks on PRGs from constant-degree polynomials and close current gaps in the subexponential cryptoanalysis of lightweight PRGs.
Concretely, against PRGs \(F : \mathbb{Z}_q^n \rightarrow \mathbb{Z}_q^m\) that are computed by polynomials of degree \(d\) over a field \(\mathbb{Z}_q\) and have a stretch of \(m = n^{1+e}\) we give an attack with space and time complexities \(n^{O(n^{1 - \frac{e}{d-1}})}\) and noticeable advantage \(1 - {O(n^{1 - \frac{e}{d-1}}/{q})} \). If \(q\) lies in \(O(n^{1 - \frac{e}{d-1}})\), we give a second attack with the same space and time complexities whose advantage is at least \(q^{-O(n^{1 - \frac{e}{d-1}})} \). If \(F\) is of constant locality \(d\) and \(q\) is constant, we construct a third attack that has a space and time complexity of \(\exp (O(n^{1 - \frac{e'}{(q-1)d-1}}))\) and noticeable advantage \(1-O(n^{-\frac{e'}{(q-1)d-1}})\) for every constant \(e' < e\).
For the entire collection see [Zbl 1528.94002].Witness encryption from smooth projective hashing systemhttps://zbmath.org/1530.940472024-04-15T15:10:58.286558Z"Wang, Yuzhu"https://zbmath.org/authors/?q=ai:wang.yuzhu.1|wang.yuzhu"Zhang, Mingwu"https://zbmath.org/authors/?q=ai:zhang.mingwuSummary: Smooth projective hash functions, also designated as hash proof systems and witness encryption, are two powerful cryptographic primitives. The former can produce a hash value corresponding to an NP language instance in two ways, and the latter allows encrypting a message using the description of an instance in an NP language. Mostly, witness encryption is constructed using computationally expensive tools like multilinear maps or obfuscation. In this work, we build a witness encryption scheme using the smooth projection hash function (\textsf{SPHF}), which achieves efficient encryption and decryption. Specifically, we generate a zero-knowledge proof for the witness \(w\) of the NP instance \(x\) and use this proof as an instance of \textsf{SPHF} to encrypt a message. Next, we instantiate \textsf{SPHF}, the key technique of the \textsf{WE} scheme, supporting the NP-complete circuit \textsf{SAT} problem proved in the \textsf{NIZK} argument. Furthermore, based on our instantiated \textsf{SPHF}, our \textsf{WE} produces a fixed-size ciphertext, and a theoretical comparison with [\textit{D. Derler} and \textit{D. Slamanig}, Des. Codes Cryptography 86, No. 11, 2525--2547 (2018; Zbl 1408.68057)] instantiated \textsf{SPHF} from Gorth-Sahai proofs (GS-proofs) [\textit{J. Groth} and \textit{A. Sahai}, Lect. Notes Comput. Sci. 4965, 415--432 (2008; Zbl 1149.94320)] shows that our \textsf{SPHF} instantiation is more efficient than theirs.
For the entire collection see [Zbl 1516.68028].Short complete diagnostic tests for circuits with two additional inputs in some basishttps://zbmath.org/1530.940732024-04-15T15:10:58.286558Z"Popkov, Kirill A."https://zbmath.org/authors/?q=ai:popkov.kirill-andreevichSummary: We prove that any Boolean function in \(n\) variables can be modeled by a testable Boolean circuit with two additional inputs in the basis ``conjunction, oblique conjunction, disjunction, negation'' so that the circuit admits a complete diagnostic test of the length at most \(2n + 3\) with respect to stuck-at faults of the type 1 at gate outputs.