Application of Quality Function Deployment for Product Design Concept Selection

Hypergraph and network flow-based quality function deployment

Quality function deployment (QFD) has been a widely-acknowledged tool for translating customer requirements into quality product characteristics based on which product development strategies and focus areas are identified. However, the QFD method considers the correlation and effect between development parameters, but it is not directly implemented in the importance ranking of development actions. Therefore, the cross-relationships between development parameters and their impact on customer requirement satisfaction are often neglected. The primary objective of this study is to make decision-making more reliable by improving QFD with methods that optimize the selection of development parameters even under capacity or cost constraints and directly implement cross-relationships between development parameters and support the identification of interactions visually. Therefore, QFD is accessed from two approaches that proved efficient in operations research. 1) QFD is formulated as a network flow problem with two objectives: maximizing the benefits of satisfying customer needs using linear optimization or minimizing the total cost of actions while still meeting customer requirements using assignment of minimum cost flow approach. 2) QFD is represented as a hypergraph, which allows efficient representation of the interactions of the relationship and correlation matrix and the determination of essential factors based on centrality metrics. The applicability of the methods is demonstrated through an application study in developing a sustainable design of customer electronic products and highlights the improvements' contribution to different development strategies, such as linear optimization performed the best in maximizing customer requirements' satisfaction, assignment as minimum cost flow approach minimized the total cost, while the hypergraph-based representation identified the indirect interactions of development parameters and customer requirements.

An MAGDM method for design concept evaluation based on incomplete information

Design concept evaluation is a huge challenge in the R&D stage of new product development. The information in the assessments often depends on the decision-makers' individual preferences. However, sometimes the decision-makers cannot give precise and complete information because it is very difficult for them to be familiar with all the criteria. In this situation, an incomplete information decision-making matrix is established. In this paper, decision-making methods based on incomplete information are compared in the literature review. Incomplete information determination method using trust mechanism is proved as a proper way to solve this problem, and the missing information are computed based on the alternatives However, in design concept evaluation, experts commonly provide their preferences using linguistic words according to the different attributes. Hence, we propose a three-step Multiple Attributes Group Decision-making (MAGDM) method where the missing value are determined by attributes. In step one, a data repairing method is proposed based on trust theory. After that, in step two, a comprehensive weight determination method combining AHP and entropy is proposed to obtain the weight of index attributes. Finally, the Rough-TOPSIS method is applied in the design scheme ranking step. In the case study, the proposed method is implemented in a tourism product design process to show its effectiveness.

A novel integrated MADM method for design concept evaluation

Design concept evaluation plays a significant role in new product development. Rough set based methods are regarded as effective evaluation techniques when facing a vague and uncertain environment and are widely used in product research and development. This paper proposed an improved rough-TOPSIS method, which aims to reduce the imprecision of design concept evaluation in two ways. First, the expert group for design concept evaluation is classified into three clusters: designers, manufacturers, and customers. The cluster weight is determined by roles in the assessment using a Multiplicative Analytic Hierarchy Process method. Second, the raw information collection method is improved with a 3-step process, and both design values and expert linguistic preferences are integrated into the rough decision matrix. The alternatives are then ranked with a rough-TOPSIS method with entropy criteria weight. A practical example is shown to demonstrate the method's viability. The findings suggest that the proposed decision-making process is effective in product concept design evaluation.

Mask Design for Life in the Midst of COVID-19

Existing medical masks have various disadvantages, such as the environmental damage caused by disposable masks, the discomfort and poor ventilation caused by prolonged mask wearing, and the lack of aesthetic design in mass-produced masks. Thus, this study used quality function deployment, the fuzzy analytic hierarchy process, and fuzzy comprehensive evaluation to research, develop, and design masks. The aforementioned methods were also used to determine the ranking of design requirements. The following priority ranking of design requirements from most to least important was obtained: reducing discomfort at the contact between the mask and the skin (0.265), avoiding foul odor inside the mask (0.187), convenient cleaning and portability (0.166), good airtightness (0.152), suitable aesthetic design for wearing in public and on social occasions (0.130), and reducing waste (0.100). Experts evaluated mask designs, and their opinions were subject to fuzzy analysis. Specifically, 50% of the experts evaluated the designs to be “good” or “very good”. Only 29% of the experts rated the design results as “average”. Thus, the innovative mask designed in this study can meet the needs of users, overcome the drawbacks of existing masks, and provide a feasible solution for the current COVID-19 pandemic.