Preferenčné vyhľadávanie založené na viacrozmernom B-strome

Ondreička, Matúš

Title: Preference Top-k Search Based on Multidimensional B-Tree Author: RNDr. Matúš Ondreička Department: Department of Software Engineering Faculty of Mathematics and Physics Charles University in Prague Supervisor: Prof. RNDr. Jaroslav Pokorný, CSc. Author's e-mail address: ondreicka@ksi.mff.cuni.cz Supervisor's e-mail address: pokorny@ksi.mff.cuni.cz Abstract: In this thesis, we focus on the top-k search according to user pref- erences by using B+ -trees and the multidimensional B-tree (MDB-tree). We use model of user preferences based on fuzzy functions, which enable us to search according to a non-monotone ranking function. We propose model of sorted list based on the B+ -tree, which enables Fagin's algorithms to search for the top-k objects according to a non-monotone ranking function. We apply this model in the Internet environment with data on different remote servers. Furthermore, we designed novel dynamic tree-based data structures, namely, MDB-tree composed of B+ -trees, MDB-tree with lists, MDB-tree with groups of B+ -trees and multiple-ordered MDB-tree. Concurrently, we have developed novel top-k algorithms, namely, the MD algorithm, the MXT algorithm and their variants which are able search for the top-k objects ac- cording to a non-monotone ranking function. These top-k algorithms are efficient...

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