Extract ABox Modules for Efficient Ontology Querying

Extracting logically-independent fragments out of an ontology ABox can be useful for solving the tractability problem of querying ontologies with large ABoxes. In this paper, we propose a formal definition of an ABox module, such that it guarantees complete preservation of facts of a given set of individuals, and thus can be reasoned independently w.r.t. the ontology TBox. With ABox modules of this type, isolated or distributed (parallel) ABox reasoning becomes feasible, and much more efficient data retrieving from ontology ABoxes can be expected. To compute such an ABox module, we present a theoretical approach and also an approximation for $\cal SHIQ$ ontologies. Testing the approximation on different types of ontologies shows that our method is efficient and extracted ABox modules are significantly smaller than the entire ABox in average.