USING DECLARATIVE KNOWLEDGE REPRESENTATION TECHNIQUES: IMPLEMENTING TRUTH MAINTENANCE IN OPS5.

Abstract

The research reported grew out of an attempt to use OPS5 to code expertise for YES/MVS, an expert system that assists computer operators in controlling large computer centers that use the MVS operating system. The author illustrates the advantages of declarative expression of knowledge and describes how it can be used with data-driven (forward chaining) production systems, such as OPS5, in the implementation of an expert system. Using concrete examples from YES/MVS, the author discusses the control aspects needed for the execution aspects of declarative knowledge. The view of the execution control strategy as a kind of truth maintenance system (TMS) is contrasted with other aspects of TMS research. Finally, the effectiveness of OPS5 (with its RETE match algorithm) in providing the implementation environment for these techniques is analyzed.