• 제목/요약/키워드: tampered failure rate model

검색결과 4건 처리시간 0.024초

Optimal step stress accelerated life tests for the exponential distribution under periodic inspection and type I censoring

  • Moon, Gyoung-Ae;Park, Yong-Kil
    • Journal of the Korean Data and Information Science Society
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    • 제20권6호
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    • pp.1169-1175
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    • 2009
  • In this paper, the inferences of data obtained from periodic inspection and type I censoring for the step-stress accelerated life test are studied. The exponential distribution with a failure rate function that a log-linear function of stress and the tampered failure rate model are considered. The maximum likelihood estimators of the model parameters are estimated and also the optimal stress change time which minimize the asymptotic variance of maximum likelihood estimators of parameters is determined. A numerical example will be given to illustrate the proposed inferential procedures and the sensitivity of the asymptotic variance of the estimated mean by the guessed parameters is investigated.

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Optimal three step stress accelerated life tests under periodic inspection and type I censoring

  • Moon, Gyoung-Ae
    • Journal of the Korean Data and Information Science Society
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    • 제23권4호
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    • pp.843-850
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    • 2012
  • The inferences of data obtained from periodic inspection and type I censoring for the three step stress accelerated life test are studied in this paper. The failure rate function that a log-quadratic relation of stress and the tampered failure rate model are considered under the exponential distribution. The optimal stress change times which minimize the asymptotic variance of maximum likelihood estimators of parameters is determined and the maximum likelihood estimators of the model parameters are estimated. A numerical example will be given to illustrate the proposed inferential procedures.

Optimal Plan of Partially Accelerated Life Tests under Type I Censoring

  • Moon, Gyoung-Ae
    • Journal of the Korean Data and Information Science Society
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    • 제5권2호
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    • pp.87-94
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    • 1994
  • In this paper, we consider optimum plan to determine stress change times under the three-step stress PALTs, assuming that each test units follows an exponential distribution. The tampered random variable(TRV) model for the three-step stress PALTs setup are introduced, and maximum likelihood estimators(MLEs) of the failure rate and the acceleration factors are obtained. The change times to minimize the generalized asymptotic variance(GAVR) of MLEs of the failure rate and the acceleration factors are proposed for the three-step stress PALTs.

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Parameter Estimation of the Two-Parameter Exponential Distribution under Three Step-Stress Accelerated Life Test

  • Moon, Gyoung-Ae;Kim, In-Ho
    • Journal of the Korean Data and Information Science Society
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    • 제17권4호
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    • pp.1375-1386
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    • 2006
  • In life testing, the lifetimes of test units under the usual conditions are so long that life testing at usual conditions is impractical. Testing units are subjected to conditions of high stress to yield informations quickly. In this paper, the inferences of parameters on the three step-stress accelerated life testing are studied. The two-parameter exponential distribution with a failure rate function that a log-quadratic function of stress and the tempered failure rate model are considered. We obtain the maximum likelihood estimators of the model parameters and their confidence regions. A numerical example will be given to illustrate the proposed inferential procedures.

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