The Reliability Analysis of Step-Stress Accelerated Life Tests Under Generalized Gamma Lifetime Distributions With Type-II Censoring

• Main Authors: Chia-hua Chang, 張家華
• Other Authors: Tsai-hung Fan
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/02860347123830041823

碩士 === 國立中央大學 === 統計研究所 === 100 === High reliability products through strictly controlled in the manufacturing process, so their lifetimes are longer under normal environment. Accelerated life test is often useful to observe enough lifetime information of the products. In this thesis, we discuss the step-stress accelerated life testing for the products whose lifetimes are of generalized gamma distribution in which the mean lifetime of each component is a log-linear function of the levels of the stress variables under Type-II censoring scheme with cumulative exposure model. Maximum likelihood estimates are developed for the model parameters with the aid of parametric bootstrap method to estimate the standard errors of the MLEs. Subjective Bayesian inference incorporated with the Markov chain Monte Carlo method is also addressed. We also discuss model fitting issue regarding the generalized gamma distribution andWeibull distribution via different model selection criteria. Simulation study reveals that when the data follow Weibull distribution but are fitted by generalized gamma distribution, the results are acceptable. On the contrary, fitting the data that actually are generalized gamma distributed by the Weibull distribution may result in considerably inaccurate results.