Combining Rule and Ontology Reasoners for the Semantic Web

Using rules in conjunction with ontologies is a major challenge for the Semantic Web. We propose a pragmatic approach for reasoning with ontologies and rules, based on the Semantic Web standards and tools currently available. We first achieved an implementation of SWRL, the emerging OWL/RuleML-combining rule standard, using the Protégé OWL plugin. We then developed a Protégé plugin, SWRLJessTab, which enables to compute inferences with the Racer classifier and the Jess inference engine, in order to reason with rules and ontologies, both represented in OWL. A small example, including an OWL ontology and a SWRL rule base, shows that all the domain knowledge, i.e. the SWRL rule base and the OWL ontology, is required to obtain complete inferences. It illustrates that some reasoning support must be provided to interoperate between SWRL and OWL, not only syntactically and semantically, but also inferentially.