Abstract: For group multi-criteria assignment problems with linguistic assessment information,a new method based on evidential reasoning and two tuple is proposed,in which the decision-makers' weights and the evaluation criteria weights are incomplete certain,and the assessment information may be between two linguistic assessment grades or not be given by the decision makers. Firstly the evidential reasoning algorithm is applied to calculate the belief degree that any candidate accomplishes any task is belonging to any linguistic assessment grade. Secondly,according to the belief degree obtained above and with the function △ and △^-1 of two tuple,the original assessment matrices are aggregated into the synthetic efficiency matrix. The nonlinear mixed integral programming model is constructed based on the incomplete certain information of the decision makers'weights and criteria weights,and the model is worked out with the improved Particle Swarm Optimization Algorithm and Hungary Algorithm. Finally an example is given to show the feasibility and availability of this method.

Key words: group linguistic assignment problem, incomplete certain information, evidential reasoning, two-tuple, particle swarm optimization algorithm