Measuring similarity between ontologies

Abstract. Ontologies now play an important role for many knowledge-intensive applications for which they provide a source of precisely defined terms. How-ever, with their wide-spread usage there come problems concerning their prolif-eration. Ontology engineers or users frequently have a core ontology that they use, e.g., for browsing or querying data, but they need to extend it with, adapt it to, or compare it with the large set of other ontologies. For the task of detecting and retrieving relevant ontologies, one needs means for measuring the similar-ity between ontologies. We present a set of ontology similarity measures and a multiple-phase empirical evaluation.