Abstract
Several attempts have been already made to develop similarity measures for ontologies. We noticed that some existing similarity measures are ad-hoc and unprincipled. In addition, there is still a need for similarity measures which are applicable to expressive Description Logics and which are terminological. To address these requirements, we have developed a new family of similarity measures. Two separate empirical studies have been carried out to evaluate the new measures. First, we compare the new measures along with some existing measures against a gold-standard. Second, we examine the practicality of using the new measures over an independently motivated corpus of ontologies.