Seminar in applied mathematics and statistics
SPEAKER: Sharmishtha Mitra (IIT Kanpur, India)
TITLE: Analysis of Life Testing Models under Different Censoring and Stress Acceleration Schemes
ABSTRACT: Traditional life-testing experiments are conducted under normal operating conditions. As against this, Accelerated life test (ALT) is a modern experimental strategy to obtain information on life distributions of highly reliable products. The main idea is to expose sampled units to one or more stress factors, so as to ensure their early failure. A Step-Stress ALT (SSALT) is a particular type of ALT, which ensures an efficient estimation of parameters from lifetime distributions in a relatively shorter period of time. The stress structure and the lifetime distribution are combined through the stress-acceleration model to get the comprehensive ALT model. The analysis relies on life and stress data or time-to-failure data at a specific stress level. Data are either complete or censored.
In our study, we have used two different stress models, viz., the Cumulative Exposure and Khamis-Higgins models, with respect to the one and two-parameter exponential distributions, and the two-parameter Weibull distributions, respectively, under various censoring schemes. Both Bayesian and frequentist (wherever possible) approaches have been applied for the estimation of parameters and construction of their confidence/credible intervals. Under Bayesian analysis, estimation with order restriction on the mean lifetimes of units has been considered as well.
Wednesday, May 29 at 15.15: Frank van der Meulen
Tuesday, July 2 at 13.15: Gaurav Khemka