Refining the structure of terminological systems: terminology= schema+ views (original) (raw)

1994, PROCEEDINGS OF THE …

Traditionally, the core of a Terminological Knowledge Representation System (TKRS) consists of a so-called TBox, where concepts are introduced, and an ABox, where facts about individuals are stated in terms of these concepts. This design has a drawback because in most applications the TBox has to meet two functions at a time: on the one hand, similar to a database schema, framelike structures with typing information are introduced through primitive concepts and primitive roles; on the other hand, views on the objects in the knowledge base are provided through defined concepts. We propose to account for this conceptual separation by partitioning the TBox into two components for primitive and defined concepts, which we call the schema and the view part. We envision the two parts to differ with respect to the language for concepts, the statements allowed, and the semantics. We argue that by this separation we achieve more conceptual clarity about the role of primitive and defined concepts and the semantics of terminological cycles. Moreover, three case studies show the computational benefits to be gained from the refined architecture. *This work was partly supported by the Commission of the European Union under ESPRIT BRA 6810 (Compulog 2), by the German Ministry of Research and Technology under grant ITW 92-01 (TACOS), and by the CNR (Italian Research Council) under Progetto Finalizzato Sistemi Informatici e Cakolo Parallelo, LdR "Ibridi." Person, having exactly one name of type Name and at least one affiliation of type Department. This is similar to class declarations in object-oriented systems. For this purpose, a simple language is sufficient. Cycles occur naturally in modeling tasks, e.g., the boss of an Employee is also an Employee. Such declarations have lIn (Lenzerini & Schaerf 1991) a combination of a weak language for ABoxes and a strong language for queries has been investigated.