Bayesian and Multiple Bayesian Analysis of the Reliability Performances for Series System with Cold Standby Units

By using Bayesian and multiple Bayesian method, the failure probability, reliability and mean time to failure(MTTF) of series system with cold standby units are estimated. At last, we compare the two estimators by means of Monte_Carlo simulation.

Optimal Replacement Policy for Cold Standby System

Investigators are attracted by the complexity and significance of preventive maintenance problem,and there are hundreds of maintenance models and methods to solve the maintenance problems of companies and army,going with a lot of investigative harvests. However,one-component system or series system is focused by most of the literature.The problem of preventive maintenance（PM） on cold standby repairable system does not attach importance despite the fact that the cold standby repairable system is ubiquitous in engineering systems.In this paper,an optimal replacement model for gamma deteriorating system is studied.This methodology presented uses a gamma distribution to model the material degradation,and the impact of imperfect maintenance actions on system reliability is investigated.After an imperfect maintenance action,the state of a degrading system is assumed as a random variable and the maintenance time follows a geometric process.A maintenance policy（N）is applied by which the system will be repaired whenever it experiences the Nth PM,and an optimal policy（N~＊） could be determined numerically or analytically for minimizing the long-run average cost per unit time.A numerical example about how to confirm the optimal maintenance time by the inspecting information of liquid coupling device is given to demonstrate the use of this policy.This paper presents a condition-based replacement policy for cold standby repairable system under continuous monitoring.Its contribution embody in two aspects,relaxing the restrictions of hypothesis and investigating the condition-based maintenance policy of the cold standby repairable system which is ignored by others.

Reliability analysis for a cold standby system under stepwise Poisson shocks

In this paper,a two-dissimilar-component cold standby repairable system maintained by a repairmanis investigated.The system fails due to either intrinsic factors or external shocks.Assume that shocks arrive according to a stepwise Poisson process,the intensity of which varies with respect to the number of failures of the working component.Repair after failure is imperfect.Using the supplementary variable method and the vector Markov process theory,we obtain some important reliability index for the system.By the renewal reward theorem,an optimal replacement policy N∗is derived by minimising the average cost rate of the system.Numerical examples are presented to validate the theoretical results.

STRUCTURES OF SYSTEMS WITH EXPONENTIAL LIFE DISTRIBUTIONS

Structures of monotone systems and cold standby systems with exponen-tial life distributions and dependent components are studied. It is shown that a mono-tone system composed of components with multivariate HNBUE life distributions isessentially a series system composed of components with multivariate exponential lifedistributions. Also, it is proved that for cold standby systems composed of componentswith multivariate NBU life distributions, all but oue of the components are degenerateat zero while the remaining one is exponential. In addition, several equivalent char-acterizations of multivariate exponential distribution are provided in the multivariateHNBUE life distribution class which include many existing results as special cases.

Optimization of a Multi-node System Reliability Model

In order to improve the reliability of an electronic or a computer system, redundant components always need to be added as part of the system. When an active component falls, a standby component will be activated to guarantee the system in operation continuously. The standby component and the switching device have been usually assumed to be continuously functional duriv,g the setup of the reliability model. In fact, it is these two asstuxtptions that induce deviations during modeling and introduce variances for the system reliability design. Through modeling and optiming the dependability of the synchronous clock system that decomposed from a multi-node system, a new reliability model which takes these two elements into consideration has been developed. Simulation results demonstrate that the upgraded reliability model is closer Io the actual dependability of the real system. The capability of the system reliability design is also improved as a result.