December 1989 - Vol. 32 No. 12

December 1989 issue cover image

Features

Research and Advances

Episodic skeletal-plan refinement based on temporal data

ONCOCIN is a medical expert system that extends the skeletal-planning technique to an applciation area where the history of past events and the duration of actions are important. The system's knowledge base is designed to reflect a hierarchical model of the domain, and its control and inference mechanisms encourage a mixed-initiative style of interaction between the computer and the user.
Research and Advances

Parse tree annotations

A technique for associating rewrite rules with productions so that many high-level transformations of a source file can be generated easily is described. While eclipsed in power by other editing and compiler generation systems supporting management of both synthesized and inherited attributes, this approach is especially simple to employ and is sufficient in power to deal with a wide class of problems arising from practical applications.

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