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In 1975, Zadeh proposed Type-2 Fuzzy Sets (T2 FS) as an extension to the previously introduced ordinary fuzzy sets (now called type-1 fuzzy sets). Type-2 fuzzy sets have the ability to capture the uncertainty about membership functions of fuzzy sets through fuzzification of the membership function of type-1 fuzzy sets. Instead of using a single crisp number from the unit interval [0, 1] as the membership value, as is done in a type-1 fuzzy set, in a T2 FS one or more crisp numbers are used as membership values, and with different strengths. More precisely, a membership grade in a T2 FS is a type-1 fuzzy set; this introduces a new third dimension into a fuzzy set which provides more degrees of freedom for handling uncertainties. Unfortunately, practitioners are still cautious to put general T2 FSs to real use due to their computational complexity. Consequently, there has been extensive research toward simplification of …