Top-k Linked Data Query Processing [chapter]

Andreas Wagner, Thanh Tran Duc, Günter Ladwig, Andreas Harth, Rudi Studer
2012 Lecture Notes in Computer Science  
In recent years, top-k query processing has attracted much attention in large-scale scenarios, where computing only the k "best" results is often sufficient. One line of research targets the so-called top-k join problem, where the k best final results are obtained through joining partial results. In this paper, we study the top-k join problem in a Linked Data setting, where partial results are located at different sources and can only be accessed via URI lookups. We show how existing work on
more » ... -k join processing can be adapted to the Linked Data setting. Further, we elaborate on strategies for a better estimation of scores of unprocessed join results (to obtain tighter bounds for early termination) and for an aggressive pruning of partial results. Based on experiments on real-world Linked Data, we show that the proposed top-k join processing technique substantially improves runtime performance. PREFIX drugbank : PREFIX owl : SELECT * WHERE { ?d owl : sameAs ? d2 . ?d drugbank : d r u g C a t e g o r y ? c . ?d drugbank : c a s R e g i s t r y N u m b e r ? i d . } Query. 4. PREFIX d b p e d i a : PREFIX owl : PREFIX r d f s : PREFIX d c t e r m s : SELECT * WHERE { ? x d c t e r m s : s u b j e c t d b p e d i a : Western Europe . ? x owl : sameAs ? x2 . ? x2 r d f s : l a b e l ? l . } Query. 5. PREFIX d b p e d i a : PREFIX owl : SELECT * WHERE { ? x d c t e r m s : s u b j e c t d b p e d i a : C h a n c e l l o r s o f G e r m a n y . ? x2 owl : sameAs ? x . } Query. 6. PREFIX f o a f : PREFIX owl : PREFIX d c t e r m s :
doi:10.1007/978-3-642-30284-8_11 fatcat:w74pjfkobnhktfijhsz45fsasq