Using PSL to Extend and Evaluate Event Ontologies

The representation of events plays a key role in a wide range of Semantic Web applications, and several ontologies have been proposed to support this task. However, a review of existing event ontologies on the web reveals limited reasoning being done in their applications. To investigate this, we designed a set of reasoning problems (competency questions) aimed at providing a pragmatic assessment of the reasoning capabilities of three well-known Semantic Web event ontologies – SEM, The Event Ontology, and LODE. Using OWL and SWRL axiomatizations of the Process Specification Language (PSL) Ontology, we specify maximal extensions of the existing event ontologies. We then evaluate the resulting set of OWL and SWRL ontologies against our reasoning problems, using the results to both assess the abilities of existing Semantic Web event ontologies, and to explore the potential gains that may be achieved through additional axioms.