A Re ned Architecturefor Terminological Systems : Terminology = Schema +

Traditionally, the core of a Terminological Knowledge Representation System (TKRS) consists of a TBox or terminology, where concepts are introduced, and an ABox or world description, where facts about individuals are stated in terms of concept memberships. This design has a drawback because in most applications the TBox has to meet two functions at a time: On the one hand|similarly to a database schema|frame-like structures with type information are introduced through primitive concepts and primitive roles; on the other hand, views on the objects in the knowledge base are provided through deened concepts. We propose to account for this conceptual separation by partitioning the TBox into two components for primitive and deened concepts, which we call the schema and the view part. We envision the two parts to diier with respect to the language for concepts, the statements allowed, and the semantics. We argue that this separation achieves more conceptual clarity about the role of primitive and deened concepts and the semantics of terminological cycles. Two case studies show the computational beneets to be gained from the reened architecture.