Int J Performability Eng ›› 2014, Vol. 10 ›› Issue (3): 281-290.doi: 10.23940/ijpe.14.3.p281.mag

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Bilevel-Programming Based Time-Censored Ramp-Stress ALTSP with Warranty Cost


  1. Department of Operational Research, University of Delhi, Delhi 110007, INDIA


Life test sampling plans are used to determine the acceptability of a product with respect to its lifetimes. Introducing acceleration in life testing experiments helps in obtaining estimates of reliability measures of high reliability products quickly. An accelerated life test (ALT), with linearly increasing stress is a ramp-stress test. This paper deals with a design of optimum time-censored ramp-stress accelerated life test sampling plan (ALTSP) where the product life is assumed to follow log-logistic distribution. The operating characteristic function of the uniformly most powerful (UMP) life test is deduced. The decision criterion is based on UMP test and the estimated median life time. The optimal plan consists in finding optimum sample size, sample proportions allocated to each stress, and stress rate factor by minimizing the expected total cost per lot. Bilevel-programming approach is used for this purpose. The method developed has been illustrated using a numerical example.

Received on October 09, 2013, revised on December 01, 2013 and March 25, 2014
References: 15