Dempster-Shafer theory and rule strengths in expert systems

The D-S theory originated from the concept of lower and upper probabilities induced by a multi-valued mapping. The focal element in the D-S theory is the union of the granules in a granule set. Moreover, these granules form a partition of the focal element, since they are mutually exclusive. Since the mapping in D-S theory has been extended to a probabilistic one, the probability mass of an evidential element is now distributed among its granules. The authors present the basics of D-S theory and go on to outline three examples where it is used with rule strengths in expert systems