Using defeasible logic to control selection of a business forecasting method

An approach to nonmonotonic reasoning in expert systems is presented that does not rely on numerical probabilities or confidence factors, using instead rules-of-thumb that cover the normal or typical case but are known to have exceptions. A logic for such defeasible rules is implemented in d-Prolog, an extension of Prolog. FORE, a prototype, knowledge-based system written in d-Prolog, is also presented. FORE uses ordinary Prolog rules to specify when a business forecasting method is indicated or counterindicated. A small kernel of defeasible metarules controls FORE's final recommendations.<>