Dynamic Skyline Computation with LSD Trees

Given a set of high-dimensional feature vectors <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mo>⊂</mo><msup><mi mathvariant="double-struck">R<...

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Main Author: Dominik Köppl
Format: Article
Language:English
Published: MDPI AG 2023-02-01
Series:Analytics
Subjects:
Online Access:https://www.mdpi.com/2813-2203/2/1/9
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author Dominik Köppl
author_facet Dominik Köppl
author_sort Dominik Köppl
collection DOAJ
description Given a set of high-dimensional feature vectors <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mo>⊂</mo><msup><mi mathvariant="double-struck">R</mi><mi>n</mi></msup></mrow></semantics></math></inline-formula>, the skyline or Pareto problem is to report the subset of vectors in <i>S</i> that are not dominated by any vector of <i>S</i>. Vectors closer to the origin are preferred: we say a vector <i>x</i> is dominated by another distinct vector <i>y</i> if <i>x</i> is equally or further away from the origin than <i>y</i> with respect to all its dimensions. The dynamic skyline problem allows us to shift the origin, which changes the answer set. This problem is crucial for dynamic recommender systems where users can shift the parameters and thus shift the origin. For each origin shift, a recomputation of the answer set from scratch is time intensive. To tackle this problem, we propose a parallel algorithm for dynamic skyline computation that uses multiple local split decision (LSD) trees concurrently. The geometric nature of the LSD trees allows us to reuse previous results. Experiments show that our proposed algorithm works well if the dimension is small in relation to the number of tuples to process.
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spelling doaj.art-16d0e1f2d78e4dc8869814061d88b6272023-11-17T09:09:59ZengMDPI AGAnalytics2813-22032023-02-012114616210.3390/analytics2010009Dynamic Skyline Computation with LSD TreesDominik Köppl0M&D Data Science Center, Tokyo Medical and Dental University, Tokyo 113-8510, JapanGiven a set of high-dimensional feature vectors <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mo>⊂</mo><msup><mi mathvariant="double-struck">R</mi><mi>n</mi></msup></mrow></semantics></math></inline-formula>, the skyline or Pareto problem is to report the subset of vectors in <i>S</i> that are not dominated by any vector of <i>S</i>. Vectors closer to the origin are preferred: we say a vector <i>x</i> is dominated by another distinct vector <i>y</i> if <i>x</i> is equally or further away from the origin than <i>y</i> with respect to all its dimensions. The dynamic skyline problem allows us to shift the origin, which changes the answer set. This problem is crucial for dynamic recommender systems where users can shift the parameters and thus shift the origin. For each origin shift, a recomputation of the answer set from scratch is time intensive. To tackle this problem, we propose a parallel algorithm for dynamic skyline computation that uses multiple local split decision (LSD) trees concurrently. The geometric nature of the LSD trees allows us to reuse previous results. Experiments show that our proposed algorithm works well if the dimension is small in relation to the number of tuples to process.https://www.mdpi.com/2813-2203/2/1/9skyline computationparallel algorithmspreference evaluationapplication of geometric data structures
spellingShingle Dominik Köppl
Dynamic Skyline Computation with LSD Trees
Analytics
skyline computation
parallel algorithms
preference evaluation
application of geometric data structures
title Dynamic Skyline Computation with LSD Trees
title_full Dynamic Skyline Computation with LSD Trees
title_fullStr Dynamic Skyline Computation with LSD Trees
title_full_unstemmed Dynamic Skyline Computation with LSD Trees
title_short Dynamic Skyline Computation with LSD Trees
title_sort dynamic skyline computation with lsd trees
topic skyline computation
parallel algorithms
preference evaluation
application of geometric data structures
url https://www.mdpi.com/2813-2203/2/1/9
work_keys_str_mv AT dominikkoppl dynamicskylinecomputationwithlsdtrees