Computing with words for interval type-2 fuzzy set based on fuzzy extension principle

Because there exists drawback in traditional type-1 fuzzy sets to deal with uncertainty, type-2 fuzzy sets have been proposed to replace their type-1 counterparts. This paper presents numerical calculation procedure of computing with words for interval type-2 fuzzy set (IT2 FS) based on fuzzy extension principle. Three kinds of interval type-2 fuzzy sets, such as discrete, semi-discrete and continuous, are focused. We will have given specific application formulas based on fuzzy extension principle. A few numerical examples are employed to verify that our proposing method is effective and valuable.