A Framework for Control in Production Systems

Abstract

A formal scheme for representing control in production systems is defined. The scheme allows control to be directly specified independently of conflict resolution and thus allows the issues of control and nondeterminism to be treated separately. Unlike previous approaches, it allows control to be examined within a uniform and consistent framework. It is shown that the scheme provides a basis for implementing control constructs which, unlike existing schemes, retain all the properties desired of a knowledge based system---modularity, flexibility, extensibility and adaptive capacity. Within the formalism it is also possible to provide a meaningful notion of the power of control constructs. This enables the types of control required in produ ction systems to be examined and the capacity of various schemes to meet these requir em ents to be determined.