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Querying the Semantic Web with Preferences
Wolf Siberski1, Jeff Z. Pan2, and Uwe Thaden1
1L3S and University of Hannover, Hannover
siberski@l3s.de
thaden@l3s.de
2University of Aberdeen
jpan@csd.abdn.ac.uk
Abstract. Ranking is an important concept to avoid empty or overfull and unordered result sets. However, such scoring can only express total orders, which restricts its usefulness when several factors influence result relevance. A more flexible way to express relevance is the notion of preferences. Users state which kind of answers they ‘prefer’ by adding soft constraints to their queries.
Current approaches in the Semantic Web offer only limited facilities for specification of scoring and result ordering. There is no common language element to express and formalize ranking and preferences. We present a comprehensive extension of SPARQL which directly supports the expression of preferences. This includes formal syntax and semantics of preference expressions for SPARQL. Additionally, we report our implementation of preference query processing, which is based on the ARQ query engine.
Keywords: preferences, query language, semantic web.
LNCS 4273, p. 612 ff.
lncs@springer.com
© Springer-Verlag Berlin Heidelberg 2006