• Journal of the Korean Data and Information Science Society
• /
• v.14 no.4
• /
• pp.951-963
• /
• 2003

In this paper, we propose goodness of fit test statistics based on the estimated Kullback-Leibler information functions using the data from three step stress accelerated life test. This acceleration model is assumed to be a tampered random variable model. The power of the proposed test under various alternatives is compared with Kolmogorov-Smirnov statistic, Cramer-von Mises statistic and Anderson-Darling statistic.

• Proceedings of the Korean Statistical Society Conference
• /
• 2000.11a
• /
• pp.235-240
• /
• 2000

In this paper a test of fit for exponentiality and we propose the estimator of Kullback-Leibler Information functions using the data from accelerated life tests. This acceleration model is assumed to be a tampered random variable model. The procedure is applicable when the exponential parameter based on the data from accelerated life tests is or is not specified under null hypothesis. Using Simulations, the power of the proposed test based on use condition of accelerated life test under alternatives is compared with that of other standard tests in the small sample.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.7
• /
• pp.751-757
• /
• 2012

An accelerated life test (ALT) is a test method that forces components to fail more quickly than they would under use conditions by applying higher overstresses. When two or more accelerating stresses are involved in an ALT, an interaction effect may occur. In previous studies, mostly ALTs without considering an interaction of accelerated stresses and accelerated life models were proposed. The life data obtained are extrapolated using a life-stress relationship to estimate the life distribution at use conditions. We use the general log-linear relationship to model the dependence of life in the Weibull distribution on stress. Therefore, this study suggests the acceleration factor model between the lives at use conditions and accelerated conditions by using mechanical component life data considering an interaction effect. Further, the accelerated life test method and acceleration factor model proposed in this paper will be the basis for adopting an accelerated life test with accelerated stress interactions.

• International Journal of Reliability and Applications
• /
• v.1 no.2
• /
• pp.155-165
• /
• 2000

In this paper, we propose some estimators of Kullback- Leibler Information functions using the data from three step stress accelerated life tests. This acceleration model is assumed to be a tampered random variable model. Some asymptotic properties of proposed estimators are proved. Simulations are performed for comparing the small sample properties of the proposed estimators under use condition of accelerated life test.

• Journal of Korean Institute of Industrial Engineers
• /
• v.20 no.1
• /
• pp.39-51
• /
• 1994

Almost all accelerated life tests assume that no basic failure mechanism changes within the test stresses. But accelerated life test, considering failure mechanism changes, is needed since failure mechanism changes when accelerating beyond the used stress. This paper studies the analysis when the failure mechanism changes within the test stresses. The piecewise linear regression, which the join point of two lines is estimated, is applied In particular, two accelerated life tests, with and without a change in failure mechanism are examined.

• Proceedings of the Korea Society for Industrial Systems Conference
• /
• 2009.05a
• /
• pp.107-113
• /
• 2009

This paper deals with noninformative priors for such as Jeffres' prior, reference prior and probability matching prior for scale parameter of exponential distribution when the data are collected in multiple step stress accelerated life tests. We find the noninformative priors for this model and show that the reference prior satisfies first order matching criterion. Using artificial data, we perform Bayesian analysis for proposed priors.

• Journal of Applied Reliability
• /
• v.9 no.1
• /
• pp.47-58
• /
• 2009

In this paper, an accelerated life test procedure for a vacuum cleaner motor is proposed. We investigate the failure mechanism of the motor and select some accelerating factors and determine the orifice size as a key accelerating factor. Three stress levels of orifice size are tested and the failure data with censored data are analyzed. The modified accelerating test will reduce the test time in design phase by using the accelerating factor.

• Journal of the Korean Data and Information Science Society
• /
• v.26 no.1
• /
• pp.281-288
• /
• 2015

In this paper, the maximum likelihood estimators and confidence intervals for parameters of Weibull distribution are derived under three level constant stress accelerated life tests and the assumption that a log quadratic relationship exits between stress and the scale parameter ${\theta}$. The compound linear plan proposed by Kim (2006) is used to allocate the test units at each stress level, which performed nearly as good as the optimum quadratic plan and had the advantage of simplicity. Some simulation studies are given.

• Journal of the Korean Statistical Society
• /
• v.35 no.3
• /
• pp.225-238
• /
• 2006

This paper considers noninformative priors for the scale parameter of exponential distribution when the data are collected in step stress accelerated life tests. We find the Jeffreys' and reference priors for this model and show that the reference prior satisfies first order matching criterion. Also, we show that there exists no second order matching prior in this problem. Some simulation results are given and we perform Bayesian analysis for proposed priors using some data.

• Journal of Drive and Control
• /
• v.20 no.3
• /
• pp.9-14
• /
• 2023

In this paper, the selection of a reliable accelerated life test code for a 2-ton forklift was accomplished by choosing the driving resistance coefficient failure-free test time based on a 10,000-hour B₁₀ life. The overall life and average equivalent load of the vehicle were then calculated based on actual driving test conditions using the selected driving resistance coefficient. The gear train's accelerated life test code was selected by adjusting the equivalent load to a torque and rotation speed that did not exceed 125%(about 75HP) of the vehicle rated power. The safety of the test standards was validated by conducting an actual accelerated life test utilizing the proposed test method in this study and comparing the test result with the corresponding theoretical value. It is anticipated that the reliability of the accelerated life test in this paper will be enhanced, by incorporating actual driving performance data collected directly from the forklift and adjusting the conditions used in developing the accelerated life test code.