Two-unit Cold Standby Redundant System Research Articles

Reliability analysis of a two-unit cold standby redundant system with two operating modes

This paper considers a two unit cold standby redundant system subject to a single repair facility with exponential failure and general repair time distribution. Each unit can work in three different modes — normal, partial failure and total failure. There is a perfect switch to operate the standby unit on total failure of the operative unit. The system has been analysed to determine the reliability parameters e.g. mean time to system failure (MTSF), steady state availability, mean recurrence to a state and expected number of visits to a state, first two moments of time in transient state, by using the theory of Semi-Markov Process. Howard's reward structure has been super-imposed on the Semi-Markov Process to obtained expected profit of the system. A number of results obtained earlier are derived as particular cases.

Cost—benefit analysis of a one-server two-unit cold standby system subject to inspection

This paper deals with the cost—benefit analysis of a single-server two-unit cold standby redundant repairable system subject to inspection. An inspection policy model is considered in which the failure of a unit is detected by inspection only but system failure is detected instantaneously without inspection. The failure time of a unit is assumed to be exponentially distributed with parameter λ. Initially, a unit is switched on and the other one is kept as cold standby. The system breaks down if a unit fails while the other is still under repair. In this paper, the system is characterised by the probabilities of its being in the up or the down state. Integral equations are set up for these probabilities by identifying suitable regenerative epochs. Laplace transform technique is employed to solve these equations. System characteristics, namely: 1. pointwise availability of the system during (0, t 2. s-expected up-time of the system in (0, t 3. s-expected busy-period of the service facility in (0, t 4. steady-state availability of the system; are obtained to carry out the cost—benefit analysis. Numerical results pertaining to three particular cases are also presented.

Laplace transforms for the two-unit cold-standby redundant system : D. G. Linton and S. Braswell. IEEE Trans. Reliab.R-22 No. 2, June (1973), p. 105

This paper deal with a two-server, two-unit redundant system in which one unit is operative and the other is a warm standby. The operative unit can fail completely, either directly from the normal state or via a partial failure, while the warm standby unit only fails due to minor faults within it. One repairman is “regular”, he always remains with the system, and the other is an “expert” who is called when needed. The system has been analysed to determine the various reliability measures by using semi-Markov processes and regenerative processes. Numerical results and some graphs pertaining to a particular case are also included.