Specification of expert systems

The authors focus on the problems of specification of an expert system namely, what needs to be specified, what can be specified and how. Two distinct major roles for a software specification are identified: as a contract between parties involved in system development and as a blueprint for the design and implementation of the system. It is shown that these purposes require quite different specifications. The role of specification as a contract is taken by the problem specification, which essentially describes what system is to be built. The blueprint specification is complementary, and describes how the system is to be built, including a description of the knowledge to be used and a description of how to represent and reason with that knowledge