The K-Rep System Architecture

K-Rep is an object-oriented knowledge representation system based on description logic [Woods and Schmolze, 1992]. K-Rep provides a language to express descriptions (e.g., of medical concepts such as drugs, treatments, and diseases), inference mechanisms for reasoning about descriptions and their relationship to one another, and considerable supporting infrastructure. This paper presents an overview of K-Rep’s system architecture, which has been motivated in part by the needs of several applications in the area of clinical information systems [Mays et al., 1996]. It has become clear that accurate and comprehensive controlled medical terminologies are crucial for advanced clinical information systems, e.g., to achieve comparable data across the enterprise in support of outcomes analysis and inter-operation of ancillary systems, coneeptual indexing of clinical advice, and knowledge-based entry of orders for drugs, procedures, etc. Organization and maintenance of such a terminology is a formidable task: there are at least 100,000 concepts of initial interest, both national (or international) standardization and local customization of content must coexist, and the terminology will evolve significantly over time. The state of the art in medical terminologies is characterized by ad hoe definitions, manual classification, little inferential power, and no provision for collaborative development. Therefore, the area of clinical information systems has become one of our key applications. In October 1994, after several years of experience with a Common Lisp implementation of the K-Rep description logic system [Mays et al., 1991], we embarked upon a substantial redesign effort to accomplish the following objectives: