Equivalence Heuristics for Malleability-Aware Skylines

In recent years, the skyline query paradigm has been established as a reliable method for database query personalization. While early efficiency problems have been solved by sophisticated algorithms and advanced indexing, new challenges in skyline retrieval effectiveness continuously arise. Especially, the rise of the Semantic Web and linked open data leads to personalization issues where skyline queries could not be applied easily. We addressed the special challenges presented by linked open data in previous work [13] and further extend this work now by a heuristic workflow to boost efficiency. This is necessary because, the new view on linked open data dominance has serious implications on the efficiency of the actual skyline computation, since transitivity of the dominance relationships is no longer granted. Therefore, our contributions in this paper can be summarized as a) we present an intuitive skyline query paradigm to deal with linked open data b) we provide an effective dominance definition and establish its theoretical properties c) we develop innovative skyline algorithms to deal with the resulting challenges d) we design efficient heuristics for the case of predicate equivalences that may often happen in linked open data. We extensively evaluate our new algorithms with respect to performance and the enriched skyline semantics.