Introduction to type-2 fuzzy logic systems

Abstract

This paper introduces a robust fuzzy logic system, one that can handle rule uncertainties. We make use of type-2 fuzzy sets for this purpose. The development of a type-2 fuzzy logic system has led to a new operation that we call type-reduction. In the course of this development, we also study set operations on type-2 sets, properties of membership grades of type-2 sets, type-2 relations and their compositions, and defuzzification.