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Current Issues Concerning Reliability Estimation in Operational Test and Evaluation

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Master's thesis

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There are several perennial issues concerning rehability estimation in Operational Testing and Evaluation OTE. Two of these include, how should one model the underlying failure distribution of a continuous-time system, and, how can a testing agency use information from DT in order to reduce OT resource requirements. In the former issue, some OTE analysts have questioned whether or not the exponential failure distribution should be used in all cases for continuous-fim systems, and have suggested the Weibull distribution as an alternative in some instances. In the latter, the notion of combining DT and OT data has been an anathema to those involved in OTE, however, with ever-tightening military budgets, it may be time to revisit the issue. First, this thesis compares the exponential and Weibull failure distributions in terms of the amount of test time needed to demonstrate, to a given level of confidence, that the true MTTF of a system is at least as large as the minimum acceptable value, and also in terms of the actual confidence level associated with the lower confidence level procedure when the system has an increasing or decreasing failure rate function. Second, the thesis examines the behavior of an estimator for the relationship between DT and OT failure data using a Monte Carlo simulation. Finally, the thesis introduces a hierarchical Bayes approach for the estimation of the relationship between DT and OT failure data when a gamma prior distribution is assumed. Reliability estimation, Weibull distribution, Exponential distribution, Developmental testing, Operational test and evaluation.

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  • Administration and Management
  • Statistics and Probability
  • Operations Research
  • Marine Engineering
  • Test Facilities, Equipment and Methods

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