Type-2 Fuzzy Logic System and Level Set

The basic theory of a type-2 Fuzzy Logic Systems (FLSs) is presented, an efficient and simplified method to convert a type-2 fuzzy to a crisp result in a type-2 FLS is proposed, which is a straightforward way for the liberation of computation complexity, and the example shows that it also keeps the vague that it should have. A important application of fuzzy set is the research of language model,The traditional fuzzy set exist grat deficiency in the espression of natural language,but the type-2 fuzzy set can remedy the imperfect in great extent,so compare to the type-1 fuzzy set the type-2 one has a better superiority and development space. Keywords: type-2 fuzzy set; Level set; FLS; membership function;