EQuIKa: Epistemic Querying Answering in OWL2 Ontologies

Extending ontology querying facilities with the epistemic operator provides practically useful additional functionalities like ontology introspection, integrity constraints checking, etc. In this paper, we present a practical system called EQuIKa capable of epistemic inferencing on OWL 2 DL Ontologies. It implements our recently developed reduction method of epistemic queries to several subsequent standard reasoning steps. EQuIKa is implemented as a Protégé plugin, featuring a convenient querying interface alike the DL Query tab, enabling epistemic querying directly within the editor. Besides the implementation details, we discuss several optimization issues important for the feasibilityof the system in practice. First experiments demonstrate practical feasibility of our system, as the system's runtime lies in the same order of magnitude as standard reasoning tasks.