抄録
Although in many companies the design concept is very significant to developing a product, logical research of the method used to make the design concept is not progressing at all. Therefore, in the first half of this paper, we have proposed the portfolio analysis technique which makes a new design concept. In this method, a design concept is made by rearranging requirements for the design extracted from the results of the fact finding using Multiple variable analysis both with the referee and without the referee. In addition, the definition and the method of arrangement of the requirements for a design researched by our previous paper were used. The method of adapting the proposed technique was considered in this case study of digital audio players. In the case study, we presumed the design concept of two companies and tried to assume the design concept of the next product model of one company by analyzing the designs over the past two years of two higher ranking companies. In the latter half, through the same case study, we have proposed a method to make a styling concept that is a subordinate concept of the design concept made by the proposed portfolio analysis. The styling concept is made from user's cognitive evaluation structure about products using Rough set theory.
