Controlled Language for Knowledge Representation

Current expert systems represent knowledge in several different forms. In most cases, there is an object or inheritance hierarchy representing static facts about the objects, actions, or events in the domain of application, and the important relationships between them. Other types of knowledge are represented in the form of rules, usually conditionals saying what action should be performed if such and such a condition is encountered, or what conclusion can be drawn if such and such other conditions obtain. A third type of knowledge is explicit control information, either in the form of a ‘conflict resolution’ strategy, saying how to decide which of several alternatives to pursue, or (increasingly common) in the form of a statistically driven component also deciding among several competing hypotheses on the basis of prior experience. We shall not be concerned with this type of knowledge in the following.