Urn Models and Yao’s Formula
Yao’s formula is one of the basic tools in any situation where one wants to estimate the number of blocks to be read in answer to some query. We show that such situations can be modelized by probabilistic urn models. This allows us to fully characterize the distribution probability of the number of selected blocks under uniformity assumptions, and to consider extensions to non-uniform block probabilities. We also obtain a computationnally effcient approximation of Yao’s formula.
KeywordsAsymptotic Formula Exact Formula High Order Moment Uniformity Assumption Cient Approximation
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