Normal technique for ascertaining nonmembership functions of Intuitionistic Fuzzy Sets

To the questions of ascertaining nonmembership functions of intuitionistic fuzzy sets (IFS), a normalization technique for ascertaining nonmembership functions of IFS is proposed. First, the definition of IFS and the conceptions of membership functions, nonmembership functions and intuitionistic index are introduced. The methods for ascertaining membership functions of IFSs by using the existing ones similar to fuzzy sets are elaborated. Then, calculating formula for ascertaining nonmembership functions of IFS and the conception of non-hesitancy degree are exposed and the technique gets into normalization. Moreover, the theorem of properties of non-hesitancy degree is given with the course of proof. Subsequently, calculating method for ascertaining nonmembership functions of IFS based on trichotomy is proposed. Finally, the validity and rationality of the proposed method is checked with an instance of index and parameters, i.e. flight altitude, of air-raid target recognition.