Decision model for product design based on Fuzzy synthetic evaluation method

A fuzzy decision model is proposed to select an optimum design from various design alternatives. At the first, the evaluated objectives are arranged in a hierarchical structure with several levels. Secondly the relative contribution of each criterion to the overall value is quantified based on AHP method. Owing to vague concepts of the people´ feeling, the information of the degrees of satisfaction of each criteria perceptions of people on the design ideas are quantified with the membership functions of a fuzzy set. Afterward, a weighted generalized mean method is used to calculate the fuzzy probability level by level from the lowest-level objectives. After the fuzzy expected values of the top-level objectives are calculated, they are then used to make a decision quantitatively on selecting the optimal design alternative. Although a cash register is taken as an example in this study, this method can also be used on other products.