CQChecker: A Tool to Check Ontologies in OWL-DL using Competency Questions written in Controlled Natural Language

Competency Questions (CQs) play an important role in ontology development lifecycles as they represent functional ontology requirements. One of the main problems that hamper their proper use lies in the lack of tools that assist users to check if CQs are being fulfilled by the ontology being defined, particularly when these ontologies are defined in OWL (Ontology Web Language) under Description Logic formalism. Recently there has been a trend in checking CQs against ontologies using the RDF query engine SPARQL. Naturally, this language, being created for the formalism of Semantic Networks, is clearly not expressive enough, and, thus, inadequate to check the fulfillment of OWL CQs. As SPARQL queries can be performed only at the assertional level (instances), or at most the schema level, they are not shaped to entail an answer which may be deduced by the ontology using a subsumption not explicit in the ontology. The tool takes advantage of the WordNet lexical to deal with synonyms and adjectives stated in the CQs. In some cases, the tool shows an explanation of why the CQ being treated is considered valid with regard to the ontology. We present the tool’s architecture, capabilities and test examples against a number of controlled natural language CQs. Keywordscompetency questions, checking, ontology.