Collaborative Group Decision Making Methods With Group Consensus

Group decision making(GDM) refers to a process of aggregating the individuals preferences to group preferences and then ranking the alternatives. In the real world group decision problems, there is alwaysdiversity in opinions in a group. The collaboration and consensus in a group is hard to achieve because of the differences in the individuals' knowledge and interests. This issue has drawn lots of attentions from the researchers in management science and operations research field. However, there are still some drawbacks when the existing approaches are applied to solve practical group decision making problems. Thus, this dissertation focuses on the collaborative group decision making methods with group consensus. After summarizing the definition, taxonomy, and the state-of-art of group decision making, the methods for improving group collaboration and group consensus is provided. The main works will be shown as follows.(1) With respect to the collaborative group decision making problem with the alternatives'preferences, a decision method is presented. First, the number of the alternatives and the experts who are in the consensus interval is counted. Then the weight determining strategies would be selected for both alternatives and experts. The priorities and ranks of the alternatives are aggregated from the alternatives and experts based on deviation maximum principle. Finally, a numerical example is given to illustrate the effectiveness of the proposed method.(2) With respect to the collaborative group decision making problem with the alternatives' preferences, a decision method is presented. First the preferences of alternatives is given by using a optimization model. Then by comparing the experts' preferences with the alternatives' preferences, the weight of both experts and alternatives are obtained. The priorities and ranks of the alternatives are aggregated from the alternatives and experts based on deviation maximum principle. Finally, a numerical example is given to illustrate the effectiveness of the proposed method.(3) With respect to the group Analytic Hierarchy Process(AHP) consensus achieving problem, two methods are proposed. The first one is the method based on the "Individual-Group" perspective. In this method, the optimization model based on the group consensus index is provided for determining the weight of individuals.Then the democratic and autocratic consensus reaching algorithm are presented. The second one is the group AHP consensus reaching method based on the "Individual-Individual" perspective. In this method, the properties of Markov chain are used to determine the weight of individuals. Then the individual pairs with lower consensus level is recommended to revise their judgment to improve their consensus. The numerical examples are also given.(4) With respect to the group decision making problem with linguistic information, an approach of group consensus reaching method is proposed. First, the basic knowledge of 2 tuple linguistic representation model is introduced. Then the consensus reaching method is provided. This method leads the individuals in the group to a negotiation process and also the individuals'opinion is respected in the method. Given the stability of the group preferences, this method is convergence. Finally the numerical examples are given for validating this method.Finally, the conclusions,innovations and limitations of this dissertation are given. Furthermore, some suggestions for future study are discussed.