The Specification Language KARL and Its Declarative Semantics

The Knowledge Acquisition and Representation Language (KARL) combines a description of a knowledge-based system (kbs) at the conceptual level (a so-called model of expertise ) with a description at a formal and executable level. It is a specification language which allows the precise and unique description of a kbs independently from implementational details. In the paper, KARL is mainly discussed as a formal language. That is, the paper introduces a formal semantics for KARL. Because KARL allows the representation of static and dynamic (i.e., procedural) knowledge, its semantics must integrate both types of knowledge. First, an objectoriented logic L-KARL was developed which can be used to specify static knowledge. Second, dynamic logic was used to develop P-KARL for specifying knowledge about dynamics. Third, both languages had to be combined to represent a complete model of expertise. As a result, the integrated description of static and dynamic knowledge based on a well-defined declarative framework becomes possible. In Proceedings of the Workshop on Information systems Correctness and Reusability (IS-CORE), Amsterdam, September 27-30, 1994.