جستجوی مقالات مرتبط با کلیدواژه "coherent system" در نشریات گروه "ریاضی"

One of the important aims in reliability engineering is to improve the performance and increasethe reliability of systems. Increasing the reliability of a system is possible by allocating redundancies components in the structure of the system. In this paper, we use the worked and functioning spares components in the structure of coherent systems to increase its performance. The stochastic comparisons between used redundant coherent systems and redundant coherent systems with used components done. A comparison of used redundant systems and redundant system with used components will the design engineers to build more reliable system out of the good components of a failed system. Using the distortion function, we obtain a mixture representation for the lifetime of the mentioned systems. Based on different random stochastic orders, we provide conditions on reliability functions that used redundant coherent systems work better (worse) than redundant coherent systems with used components.

In this paper, statistical inference is considered for k-component coherent systems, when the system lifetime data is progressively type-II censored. In these coherent systems, it is assumed that the system structure and system signature are known and the component lifetime distribution is exponential. Pivotal and Bayesian methods are introduced for point estimation of the component lifetime parameter, and these methods are compared with the maximum likelihood and the least squares methods existing in the literature. Pivotal confidence interval, Bayesian confidence interval and confidence interval based on the likelihood ratio test are computed. Using Monte Carlo simulations, different point and interval estimates are compared and it is observed that pivotal and Bayesian methods perform better than other existing estimation methods.

In this paper, we discuss stochastic comparisons of active redundancy at component level versus system level. We also consider series systems in order to compare their lifetimes using the usual stochastic, the hazard rate and the reversed hazard rate orders, for two cases: (i) the spare and parent components are independent and have the same distribution, and then (ii) the spare and parent components are dependent and have not the same distribution.