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Towards estimating expected sizes of probabilistic skylines. (English) Zbl 06183329
Summary: We consider the maximal vector problem on uncertain data, which has been recently posed by the study on processing skyline queries over a probabilistic data stream in the database context. Let ${D}_{n}$ be a set of $n$ points in a $d$-dimensional space and $q\left(0 be a probability threshold; each point in ${D}_{n}$ has a probability to occur. Our problem is concerned with how to estimate the expected size of the probabilistic skyline, which consists of all the points that are not dominated by any other point in ${D}_{n}$ with a probability not less than $q$. We prove that the upper bound of the expected size is $O\left(min\left\{n,\left(lnq\right){\left(lnn\right)}^{d-1}\right\}\right)$ under the assumptions that the value distribution on each dimension is independent and the values of the points along each dimension are distinct. The main idea of our proof is to find a recurrence about the expected size and solve it. Our results reveal the relationship between the probability threshold $q$ and the expected size of the probabilistic skyline, and show that the upper bound is poly-logarithmic when $q$ is not extremely small.
##### MSC:
 68T Artificial intelligence 60 Probability theory and stochastic processes
##### References:
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