- 1 - When Knowledge Models Collide ( How it Happens and What to Do )

Interoperability and reuse of components and declarative knowledge are crucial to the further development of knowledge-based software. Unfortunately, it is hard to get components to interoperate and even harder to reuse other people’s work. These difficulties are often a result of incompatibilities in the knowledge models (the precise definition of declarative knowledge structures) assumed by the various components. Knowledge models are usually implicit or specified informally and arise from design choices made during system development. In this paper, we examine the choices made in Protégé, a knowledge-engineering project at Stanford University, and compare them to the choices made by the designers of the Open Knowledge Base Connectivity (OKBC) application program interface (formerly known as the Generic Frame Protocol). We show how these decisions lead to different knowledge models, discuss interoperability between Protégé and OKBC, and then close with a brief discussion of the merits of formalized knowledge models.