Knowledge-based functional specification of test and maintenance programs

An expert system prototype is presented whose aim is to select a test strategy for complex devices, logic PC boards, or systems. Given a set of resources on the board and a set of functions which are performed using these (or a subset of these) resources, the expert system produces a sequence of functions through which the board should be tested. The sequence should be among the best according to a set of criteria (testability, complexity) and subject to constraints (testability threshold, priority). The obtained sequence can be used for developing functional tests. A minimum set of rules is defined as well as default evaluation functions in order to simulate the strategy´s evolution. This prototype allows verification of the method validity on various examples. The expert system, written in OPS5 language, runs on VAX. It is made up of 350 production rules, of which 250 concern the strategy tree exploration and 100 are related to the type-1 and type-3 knowledge