TY - JOUR T1 - Some New Concepts About IT2FNs With Their Usage in Group Decision-Making Problems TT - JF - IJAORLU JO - IJAORLU VL - 8 IS - 1 UR - http://ijorlu.liau.ac.ir/article-1-571-en.html Y1 - 2018 SP - 1 EP - 21 KW - Multi-Attribute Decision Making KW - Choquet Integral KW - Ranking Function KW - IT2FN KW - Fuzzy Measure. N2 - Interavl type-2 fuzzy numbers (IT2FNs) are used in many real problems such as multiple attribute decision making (MADM) problems, to model the opinions/judgments of experts. This paper, using centroid points and uncertainty degrees of IT2FNs, presents a new method to rank them. Also, we present new methods based on Choquet integral and various types of Power average to aggregate a set of IT2FNs into a single one, separately. Finally, a new way is suggested to determine the importance degree of each criterion or decision maker in decision making problems. As an application, these methods will be applied to solve a group decision making problem. M3 ER -