Usability of upper level ontologies: The case of ResearchCyc

Repositories of knowledge about the real world are intended to serve as surrogates for the meaning and context of terms and concepts. These are being developed at two levels: (1) individual domain ontologies that capture concepts about a particular application domain; and (2) upper level ontologies that contain massive amounts of knowledge about the real world and are domain independent. This paper analyzes ResearchCyc, a version of Cyc, that attempts to capture common sense knowledge of the real world. Experience in applying ResearchCyc to web query processing is reported and the insights acquired are used to generate suggestions for improving the usability of upper level ontologies.