Managing the uncertainty aspect of reliability in an iterative product development process

N. Ganesh

Research output: ThesisPhd Thesis 2 (Research NOT TU/e / Graduation TU/e)

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This study identifies the design criteria for a method that can be used to manage the risk and uncertainty aspects of product reliability of Really New Innovations (RNI) in an Iterative Product Development Process (IPDP). It is based on 7 years of longitudinal research exploring more than 10 industrial projects and their corresponding sets of project data from the consumer electronics industry. This industry is characterized by increasing product functionality complexity, decreasing time to market (TTM), increasing globalization both in operations and development phases and reducing tolerance of customers for perceived quality issues. The traditional quality and reliability management methods focus primarily on risk management, which is not sufficient given the characteristics mentioned before. Hence there is a need to develop RNI where the risk and especially uncertainty aspects of product reliability have to be managed. Uncertainty refers to an event where the system parameters are known but the probability of occurrence or severity of the event is unknown as there is no or limited information available. The research findings showed that the Reliability Quality Matrix (RQM) is an effective method that helps to manage uncertainty in derivative products and that a new method needs to be developed to help manage uncertainty in RNI, especially for areas beyond the product parts and production process. Four design criteria for the new method were developed, which are proactiveness, completeness, flexibility, and information type. To demonstrate the validity of the design criteria, a new method, called RQM-Lite was developed and implemented in industrial projects. A prototype RQM-Lite tool was also developed to support the process. The initial implementation of the RQM-Lite method in case studies showed that it helped the project team to have a more complete scope for uncertainty indication. This is done through a top-down structured process and application of Information Granularity. Information Granularity is a process of decomposing macro elements of information into micro elements of information. As it is not possible to obtain or process all of the detailed information in the early phases of the IPDP, the concept of resolution is adapted and applied to information so that we have a new dimension called Information Resolution. This concept is used to achieve an "acceptable level of uncertainty, hence risk" to make satisficing decisions in the early phases of the IPDP. In other words, low resolution information is used to make a relative indication of the uncertainty in the RQM-Lite method rather than use only high resolution information for an absolute value. This thesis has shown how the RQM-Lite method is used to identify uncertainties proactively. By applying a top-down approach and the concept of information granularity, the required low and high resolution information can be gathered for uncertainty analysis, assessment and management. Through iterations, the information gaps can be reduced resulting in lower uncertainty. Once the required information is obtained to make an estimate of the underlying probability of occurrence, risk analysis, assessments and management can be carried out using the existing development and quality tools. The design criteria that have been developed and the prototype RQM-Lite method used to validate the criteria, when compared to the available alternatives and despite the limitations of this research, shows promise and provides more objectivity, especially in the field of uncertainty management of product reliability for RNI in IPDP.
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Industrial Engineering and Innovation Sciences
  • Brombacher, Aarnout C., Promotor
  • Wong, Yoke, Promotor
  • Lu, Yuan, Copromotor
Award date16 Dec 2009
Place of PublicationEindhoven
Print ISBNs978-90-386-2088-6
Publication statusPublished - 2009


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