Mehmet MimanEdward A. PohlPohl, Edward A.Miman, Mehmet2025-10-0620090218-53931793-644610.1142/S02185393090032892-s2.0-65249152996http://dx.doi.org/10.1142/S0218539309003289https://gcris.yasar.edu.tr/handle/123456789/6918https://doi.org/10.1142/S0218539309003289This paper provides an approach for assessing the uncertainty associated with the estimate of the availability of a two-state repairable system. During the design stage it is often necessary to allocate scarce testing resources among various components in an efficient manner. Although there are a variety of importance and uncertainty measures for the reliability of a system there are limited measures for systems availability. This study attempts to fill the gaps on availability importance measures and provide insights for techniques to reduce the variance of a system-level availability estimate efficiently. The variance importance measure is constructed such that it provides a measure of the improvement in the variance of the system level availability estimate through the reduction of the variance of the various component availability estimates. In addition a cost model is developed that trades-off cost and uncertainty. The measure is illustrated for five common system structures. Monte Carlo Simulation is used to illustrate the use of the assessment tools on a specific problem. Observations conclude that results are consistent with reliability importance measures.Englishinfo:eu-repo/semantics/closedAccessAvailability, uncertainty assessment, variance, importance measureUncertainty AssessmentAvailabilityImportance MeasureVarianceArticle