Nancy E. Reed, Elizabeth R. Stuck, James B. Moen
We introduce specialized strategies, an alternative level of reasoning, falling in generality between recognition-based reasoning and reasoning from first principles. These strategies are weak methods that are specific to a class of problems that occur in different domains. Specialized strategies are applicable not only to familiar problems in a domain, but also to problems that have not been anticipated. As a result they can provide both broad coverage currently given by "causal" reasoning and an efficiency close to that of "shallow" reasoning. The specialized strategies use inexact models of the components in the faulty system which contain only diagnostically relevant knowledge. Specialized strategies may be used in expert systems to increase efficiency, reduce brittleness, and decrease knowledge base construction effort compared to other common approaches. Examples are given from the domain of computer hardware diagnosis where two prototype expert systems were implemented.