Study on aggregation method of group decision making with grey judgment matrix

In real life, because of the limited rationality and lack of information, it is difficult for experts to give accurate judgments. A grey number is such a number whose exactly value is unknown but a range within which the value lies is known. Therefore grey number from grey system theory provides an important and useful tool to help describe the judgments of experts. The typical grey numbers include continuous grey numbers and discrete grey numbers. In this paper, the conception of intersection of group decision is set up to decide the weight of experts. Based on it, an aggregation approach is discussed to find an accordant method of group decision making with different grey judgment matrixes. Furthermore many characters of aggregation method are studied and a case study is given to show its rationality and feasibility.