Multi-level decision-making model for product design based on Fuzzy set theory

Matching the customer´s needs and various characteristics of the designed product together is the key point to develop a successful product, in this process, decision-making is very important. Owing to vague concepts frequently represented in decision data, the crisp value is inadequate to model real-life situations. In this paper, the information of the degrees of people´s satisfaction on each alternative is described by linguistic variables based on fuzzy set theory. Then the evaluated alternatives are arranged in a hierarchical structure with several levels, and the weighting function of each level criterion is quantified based on AHP method. According to the concept of the TOPSIS, a closeness coefficient is defined to determine the ranking order of all alternatives by calculating the distances to both the positive-ideal solution and negative-ideal solution simultaneously. Finally, the development of a cash register is taken as an example in this study