Precedence logic in the development of a blood bank expert system

摘要

This report describes an expert system for the deferral of human blood donors. Several methods have been implemented to assure accurate data handling for this task. First, the system is modular. Each donor test panel has an expert system mini-module which interprets the data and passes its results to an executive expert system, which then makes the final deferral decision. Second, rather than using traditional Boolean (binary) logic for the results of input variables, the system uses ternary values (positive, negative, or undetermined). Finally, a PREcedence LOGic system, Prelog, has been used as the inference method to solve the logic statements. Protection from programming errors afforded by this system, and its unique method of validation, are discussed.