Approaches to interval type-2 fuzzy multiple attribute group decision making based on grey incidence analysis and FTP utility function

In this paper, we investigate the multiple attribute group decision making (MAGDM) problems based on grey system theory and utility theory to accommodate situations where attribute values take the form of interval type-2 fuzzy sets (IT2FSs). Motivated by the idea of grey incidence analysis theory, we propose two new grey incidence degrees for aggregating the uncertain information and further extend the concept to accommodate interval type-2 fuzzy environment. Meanwhile, based on the flexible three parameter (FTP) utility function, we develop an interval type-2 fuzzy ranking weighted utility averaging (IT2FRWUA) operator, some desirable mathematical properties are discussed in detail. Then, we further integrate the proposed grey incidence degrees and the IT2FRWUA operator to develop two methods for handling MAGDM problems within the context of IT2FSs. Finally, some practical examples are provided to illustrate the practicality and effectiveness of the proposed methods.