Quality function deployment (QFD) has been developed by Toyota Motor Corporation in order to reduce time and shorten design times. QFD is composed of a set of matrices referred to as the house of quality (HOQ). A HOQ matrix can help the cross-functional team to translate customer requirements (CRs) into engineering goals. The importance of CRs and the relationships between CRs and technical characteristics (TCs) are obtained by a group of people with vague and fuzzy decision-making processes in the HOQ. In the conditions, a group decision-making method by using the combination of fuzzy set theory and genetic algorithms (GAs) can be used in QFD to determine the importance of each TC. Besides, a numerical example is illustrated to show that this group decision-making method by using the combination of fuzzy set theory and GAs can be reliably and precisely applied in QFD including TCs at the two-level hierarchy with the consideration of some constraints regarding budget and time limits of TCs for prioritizing TCs to effectively make decisions with fuzziness and ambiguousness.
