2019 年 70 巻 2E 号 p. 115-123
This paper presents the theoretical and practical investigations of a new method for prioritizing customer requirements (CRs) in the quality function deployment (QFD) process to improve the service quality of a communication system for disabled individuals. The theoretical contribution of this study is the development of a fuzzy analytic hierarchy process (fuzzy-AHP) with voting during QFD, which is based on fuzzy-set theory, the analytic hierarchy process, and linguistic voting. Fuzzy-set theory is crucial in addressing the ambiguity of linguistic terms used and judgments made by disabled people. The AHP is necessary to calculate the CR weights. A linguistic voting technique was integrated into fuzzy-AHP to consider not only the expert evaluations, but also the users' opinions on the CRs. The hybrid method proposed has the advantage of being able to be compared with existing methods in the sense that the opinions of real users are directly reflected on the CR weights in the QFD. The practical contribution of this paper is a case study on the design of an augmentative and alternative communication (AAC) system for individuals with a language disorder like aphasia. This case study was conducted to demonstrate the effectiveness of the method proposed. In the case study, 49 individuals with aphasia participated in the voting process. This is the first study to analyze the opinion data of such a large number of individuals with aphasia in the design of AAC systems. The effects of the voting technique on the CR weight are discussed by comparing the CR rankings of the method proposed with those of existing methods. The method proposed had a considerable influence on the target values of the technical characteristics used as input data in the second stage of QFD. This could lead to improving the service quality of communication systems designed for individuals with aphasia.