Product Concept Generation and Evaluation Based on QFD and Rough Set Theory

Design concept generation and evaluation are two critical processes, which have significant impact on new product success. However, these processes usually involves large amount of imprecise and subjective data and expertise, which are difficult to handle in traditional way. In order to improve the effectiveness of these processes, this paper proposes a new systematic method for design concept generation and evaluation process based on QFD and rough set theory. Traditional QFD model is modified to generate product concept alternatives form both customers' and technologists' perspectives. Then, experts' initial evaluation information is characterized by rough numbers in the form of intervals, which are capable of accommodating uncertainties and vagueness. Some operational laws of rough number are introduced to aggregate experts' individual judgments to a collective one and rank the product concept alternatives. Finally, a new diesel engine development case is used to illustrate the feasibility and effectiveness of the proposed method.