Computing Probability Masses in Rule-Based Systems

This report describes a method of computing confidences in rule-based inference systems by using the Dempster-Shafter theory. The theory is applicable to tactical decision problems which can be formulated in terms of sets of exhaustive and mutually exclusive propositions. Dempster's combining procedure, a generalization of Bayesian inference, can be used to combine probability mass assignments supplied by independent bodies of evidence. This report describes the use of Dempster's combining method and Shafer's representation framework in rule-based inference systems. It is shown that many kinds of data fusion problems can be represented in a way such that the constraints are met. Although computational problems remain to be solved, the theory should provide a versatile and consistent way of combining confidences for a large class of inferencing problems. (Author)