A fuzzy set theory based approach for target improvement problem in design and quality planning

To improve design and quality, the engineering characteristics that affect product performance are identified and the value of these characteristics adjusted to a target level to render the best product quality. This improvement depends on many factors, e.g. the cost of improvement, market position, importance of quality attributes. Usually the information on these factors is uncertain and defined linguistically. Subjectivity also plays an important role in the decision-making. To capture these problem characteristics, a fuzzy set theory based approach is proposed to solve the problem in two phases. First, engineering characteristics are prioritized through a fuzzy multicriteria decision-making procedure. Then the improvement of those of high priority is predicted through a fuzzy inference system. Numerical examples have been used to verify the proposed method and showed that it produces more accurate and justifiable results than previous methods.