Secondary membership evaluation in Generalized Type-2 Fuzzy Sets by evolutionary optimization algorithm

In this paper, a novel design method of Generalized Type-2 Fuzzy Set (GT2FS) is proposed. The GT2FS involves the secondary memberships for individual primary membership curve, which is obtained here by formulating and solving an optimization problem. To accomplish this, we have used Differential Evolution. The secondary membership of a given source, symbolizing the consistency in its primary membership assignment, is determined with respect to the composite of all the users´ primary membership functions. The performance of the proposed method of secondary membership evaluation has also been studied on an emotion recognition problem.