A two-unit cold standby system with three modes and correlated failures and repairs

The economic parameters are studied for a two-unit cold standby system with three modes and failure and repair times having bivariate exponential density as their joint distribution. The system is studied at suitable regenerative epochs to obtain these economic parameters. Explicit results have also been obtained for the case when failure and repair times are independent. Two important parameters of the system, i.e. MTSF and availability, have been studied graphically to observe the effect on them of correlation.     

A two-unit cold standby system with allowed down-time and correlated failures and repairs

This paper considers the stochastic behaviour of a two-unit cold standby system with allowed down-time and a single repair facility to repair the failed unit. It is assumed that the repair and failure times of a unit are associated with each other in some way or other and their joint distribution is bivariate exponential.     

A two-unit deteriorating standby system with inspection

This paper studies a single server two-unit standby system in which the standby can fail when offline and its repair starts only after knowing about its failure from its time to time inspection. The inter-inspection time is assumed to be arbitrarily distributed. Various measures of reliability useful to system designers and operations managers are obtained.     

A multicomponent two-unit cold standby system with three modes

This paper investigates a mathematical model of a two-unit cold standby redundant system with three possible states of each unit—normal, partially failed and failed. Each unit has n components, each having a constant failure rate and a repair rate, an arbitrary function of the time spent. These vary from component to component. Steady-state probabilities, steady-state pointwise availability, mean time to system failure and Laplace transforms of various transient probabilities have been obtained. Several earlier results are verified as special cases.     

A semi-regenerative process of two-unit warm standby system

This paper deals with two identical units warm standby system; a failure of operating unit can be detected at any time but a failure of standby unit can not be done until a system is inspected. We are able to look upon the stochastic behavior of our model as that of semi-regenerative process. The pointwise unavailability and the steady state unavailability of the system are derived by using the limit theorem of semi-regenerativeprocess. Further, we shall discuss the optimum inspection period minimizing the steady state unavailability. A numerical example is presented.     

Availability analysis of two-unit warm standby system with inspection time

This paper deals with two identical units warm standby system when a failure of unit is detected by actual inspection but a system down can be detected at any time without inspection. Where the lifetime distribution of unit is the bivariate exponential distribution and other distributions are arbitrary. The Laplace transform of the point-wise availability of the system and the steady state availability of the system are derived by using the supplementary variable method. Further, we discuss the optimum inspection period maximizing the steady state availability. A numerical example is presented.     

Analysis of a two-unit cold standby system with three modes

This paper analyses a two-unit cold standby system under the assumption that each unit works in three different modes—normal, partial failure and total failure. Failure time distributions of units are exponential, whereas repair time distributions are arbitrary. Breakdown of the system occurs when both the units are in total failure mode. Several reliability characteristics of interest to system designers as well as operations managers have been evaluated.     

A two-unit cold standby system with imperfect repair and excessive availability period

A two-unit cold standby redundant system supported by a single repair facility is considered. The units after repair do not behave like new ones and a unit can be repaired, at most, k(k < ∞) times. The failure time distribution of either unit is different after each repair. Further, the system performance is maintained for a random time even after breakdown. The reliability characteristics are provided for the model.     

A two-unit system with allowed down time and random check of standby

This paper deals with the cost-benefit analysis of a two-unit (priority and ordinary) cold standby system under two very practicable assumptions: (i) the ordinary unit goes for a check at random epochs; (ii) the system remains down for a random time if, during the repair of ordinary unit, the priority unit also fails. The important measures of system effectiveness are obtained by using the regenerative point technique (R.P.T).     

A two-unit standby power plant with imperfect switching

The reliability and MTTF of a complex system consisting of two generators connected in standby redundancy are evaluated. The object of the system is to supply power generated by a generator from a power-house to critical consumers connected by imperfect cables and switches. The reliability and MTTF have been evaluated by Boolean function technique.     

Profit analysis of two-unit standby system with rest period for the operator and correlated failures and repairs

This paper analyses a two-unit cold standby system with the provision of rest for the operator. After working a random amount of time, the operator needs to rest for a random amount of time and during the rest period the system comes down, but does not fail. Also, the failure and repair times of each unit are assumed to be correlated, by taking their joint density as a bivariate exponential. The system is observed at suitable regenerative epochs to obtain various reliability characteristics of interest to system designers as well as operations managers. Numerical results pertaining to a particular case are also presented.     

A reliability physics model for dissimilar two-unit standby system with single repair facility

In this paper, the reliability and availability analysis of a repairable dissimilar two-unit standby system is carried out using stress-strength failure model. Single repair facility with the time taken to repair a unit being either deterministic or random has been considered. The analysis is carried out for arbitrary stress, strength and repair time distributions.     

GERT analysis of a two-unit warm standby system with repair

A two-unit warm standby system has been modelled and analysed through GERT approach. A general concept of system utilization factor and availability curve have been introduced.     

GERT analysis of a two-unit cold standby system with repair

This paper presents a GERT (Graphical Evaluation and Review Technique) analysis of a two-unit cold standby system. The various performance characteristics of the system have been derived analytically.     

Analysis of a two-unit hot standby system with three modes

This paper discusses the stochastic behaviour of a two-unit hot standby redundant system having exponential failure and a single repair facility with general repair time distribution. Each unit of the system has three possible states—normal, partial failure and total failure. Breakdown of the system occurs when both the units are in total failure mode. Several reliability characteristics of interest to system designers as well as operations managers have been evaluated.     

Switch failure in a two-unit standby redundant system

In this paper we study the effect of imperfect switching on a two-unit standby redundant system, in which each unit works in three different modes (normal, partial failure and total failure) when the failure time distributions are exponential with different means and the repair times are arbitrarily distributed. Several reliability characteristics of interest to system designers as well as operations managers have been evaluated and particular cases are shown to corroborate earlier results.     

GERT analysis of a two-unit warm standby system with repair

A two-unit warm standby system has been modelled and analysed through GERT approach. A general concept of system utilization factor and availability curve has been introduced.     

A warm standby redundant system with correlated failures and repairs

This paper presents the analysis of a two-unit warm standby system assuming a bivariate exponential density for the joint distribution of failure and repair times of the units. Investigations regarding the stochastic behaviour and important reliability characteristics of the system have been made and earlier results have been verified as particular cases. A few graphs have also been provided to support the theoretical results.     

On a two-unit cold standby redundant system with random switching time

This paper, which contains two sections, deals with a two-unit cold standby redundant system with random switching time and imperfect switchover. In Section I, we use the survival functions to find the mean TFSF and the L.S.T. of the distribution to the first system failure. Finally, we find the limiting distribution to the first system failure. In Section II, we find the mean TFSF considering two types of preventive maintenance (PM), type (a) and type (b). Finally we prove that the mean TFSF with type (b) PM is greater than or equal to the mean TFSF with type (a) PM.