Reliability and realizability risk evaluation of concept designs
This thesis addresses the improvement in quality of decision making in design through the use of decomposed design evaluation. The research reported in this thesis is supported by the Design Research Methodology. To perform decomposed decision making, it is necessary to identify criteria that are deemed important for this activity. Questionnaire surveys, literature review and interviews with industry helped to identify these criteria. Reliability and realizability are two criteria that are selected for research in this thesis. The questionnaire surveys are discussed in chapter 2. A review of literature on decision making, reliability and realizability is reported in chapters 3 and 4. Methodologies for evaluating reliability and physical realizability are discussed in chapter 5. Relative reliability risk assessment methodology is applied to various examples consisting of university and industry projects in chapter 6. The application helps to reveal the strengths of the methodology and is termed ‘Verification of the methodology’. Validation issues of both the methodologies are dealt with in chapter 7 using the controlled experimental design. It is found that both the methodologies help to improve the quality of decision making during design evaluation. Relative reliability risk evaluation methodology helps to improve the quality of decision making to a substantial extent but physical realizability evaluation methodology shows only a little improvement in quality of decision making. Finally, it is suggested that the decomposed design evaluation methodology helps to improve the quality of decision making and is therefore proposed to be used by both novice and experienced designers.