CEDAR: Efficient Reasoning for the Semantic Web

We present a new version of CEDAR, a taxonomic reasoner for large-scale ontologies. This extended version provides fuller support for TBox reasoning, checking consistency, and retrieving instances. CEDAR is built on top of the OSF formalism and based on an entirely new architecture which includes several optimization techniques. Using OSF graph structures, we define a bidirectional mapping between OSF structure and the Resource Description Framework (RDF) allowing a translation from OSF queries into SPARQL for retrieving instances. Experiments were carried out using very large ontologies. The results achieved by CEDAR were compared to those obtained by well-known Semantic Web reasoners such as FaCT++, Pellet, HermiT, TrOWL, and Racer Pro. CEDAR performs on a par with the best systems for concept classification and several orders of magnitude more efficiently in terms of response time for Boolean query-answering.