Accession Number : ADA187021

Title :   Representing Control Knowledge as Abstract Task and Metarules.

Descriptive Note : Technical rept. no. 15,

Corporate Author : STANFORD UNIV CA KNOWLEDGE SYSTEMS LAB

Personal Author(s) : Clancey, William J ; Bock, Conrad

PDF Url : ADA187021

Report Date : Apr 1985

Pagination or Media Count : 70

Abstract : A poorly designed knowledge base can be as cryptic as an arbitrary program and just as difficult to maintain. Representing inference procedures abstractly, separately from domain facts and relations, makes the design more transparent and explainable. The combination of abstract procedures and a relational language for organizing domain knowledge provides a generic framework for constructing knowledge bases for related problems in other domains and also provides a useful starting point for studying the nature of strategies. In HERACLES inference procedures are represented as abstract metarules, expressed in a form of the predicate calculus, organized and controlled at rule sets. A compiler converts the rules into Lisp code and allows domain relations to be encoded as arbitrary data structures for efficiency. Examples are given of the explanation and teaching capabilities afforded by this representation. Different perspectives for understanding HERACLES' inference procedure and how it defines a relational knowledge base are discussed in some detail. Keywords: Control knowledge, Metaknowledge, Strategy, Procedural Knowledge, Explanation, Logic.

Descriptors :   *SYSTEMS ENGINEERING, *DATA BASES, COMPUTER ARCHITECTURE, CALCULUS, COMPILERS, EDUCATION, MEDICAL COMPUTER APPLICATIONS

Subject Categories : Computer Systems

Distribution Statement : APPROVED FOR PUBLIC RELEASE