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Characterizing reliability in a product/process design-assurance program

Description: Over the years many advancing techniques in the area of reliability engineering have surfaced in the military sphere of influence, and one of these techniques is Reliability Growth Testing (RGT). Private industry has reviewed RGT as part of the solution to their reliability concerns, but many practical considerations have slowed its implementation. It`s objective is to demonstrate the reliability requirement of a new product with a specified confidence. This paper speaks directly to that objective but discusses a somewhat different approach to achieving it. Rather than conducting testing as a continuum and developing statistical confidence bands around the results, this Bayesian updating approach starts with a reliability estimate characterized by large uncertainty and then proceeds to reduce the uncertainty by folding in fresh information in a Bayesian framework.
Date: October 1, 1997
Creator: Kerscher, W.J. III; Booker, J.M.; Bement, T.R. & Meyer, M.A.
Partner: UNT Libraries Government Documents Department

The use of fuzzy control system methods for characterizing expert judgment uncertainty distributions

Description: Fuzzy logic methods permit experts to assess parameters affecting performance of components/systems in natural language terms more familiar to them (e.g., high, good, etc.). Recognizing that there is a cost associated with obtaining more precise information, the authors particular interest is in cases where the relationship between the condition of the system and its performance is not well understood, especially for some sets of possible operating conditions, and where developing a better understanding is very difficult and/or expensive. The methods allow the experts to make use of the level of precision with which they understand the underlying process. The authors consider and compare various methods of formulating the process just described, with an application in reliability analysis where expert information forms a significant (if not sole) source of data for reliability analysis. The flow of information through the fuzzy-control-systems based analysis is studied using a simple, hypothetical problem which mimics the structure used to elicit expert information in Parse. They also characterize the effect of using progressively more refined information and examine the use of fuzzy-based methods as data pooling/fusion mechanisms.
Date: December 1998
Creator: Smith, R. E.; Booker, J. M.; Bement, T. R.; Parkinson, W. J.; Meyer, M. A. & Jamshidi, M.
Partner: UNT Libraries Government Documents Department