A REFINED ARCHITECTURE FOR TERMINOLOGICAL SYSTEMS - TERMINOLOGY = SCHEMA PLUS VIEWS

Traditionally, the core of a Terminological Knowledge Representation S ystem (TKRS) consists of a TBox or terminology, where concepts are int roduced, and an ABox or world description, where facts about individua ls are stated in terms of concept memberships. This design has a drawb ack 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 str uctures with type information are introduced through primitive concept s and primitive roles; on the other hand, views on the objects in the knowledge base are provided through defined concepts. We propose to ac count for this conceptual separation by partitioning the TBox into two components for primitive and defined concepts, which we call the sche ma End the view part. We envision the two parts to differ with respect to the language for concepts, the statements allowed, and the semanti cs. We argue that this separation achieves more conceptual clarity abo ut the role of primitive and defined concepts and the semantics of ter minological cycles. Two case studies show the computational benefits t o be gained from the refined architecture. (C) 1998 Elsevier Science B .V.