On a compound redundant system without repair

This paper deals with the reliability considerations on a redundant system consist of two subsystems connected in series, in which they have a similar warm-standby subsystem, respectively. And these four subsystems are composed of several identical units in parallel redundancy, respectively and are connected with switching devices each other.The purpose of this paper is to attain the following two subjects; (1) to utilize the surviving units at any switch-over point of time, as many as possible, making use of the switching devices as mensioned above, and (2) to deal with various complex redundant systems with or without switching devices, simultaneously.In these considerations we have obtained the reliability function and mean time to system failure (MTSF) of this system.     

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.     

Reliability consideration on a compound redundant system with repair

This paper considers a standby-redundant system consisting of 2 systems, in which one is main and the other is its standby-redundant system. These systems also consist of 2 subsystems connected in series.A feature of this system is that the system has 2 switching devices connecting subsystems, in addition to one connecting main and standby systems, in order to utilize surviving subsystem. In this consideration it is assumed that all the units are repairable.We shall obtain the system reliability, the mean time to system failure, the steady state availability, and examine numerically the effects of this model to the usual one without particular switching devices.     

Stochastic behaviour and profit analysis of a redundant system with slow switching device

This paper studies various economic measures of a two unit cold standby system subject to slow transfer switch. Each unit of the system can be in one of the three modes—normal, partial failure and total failure. Repair time distribution of the units are general while all other transition time distributions are negative exponential. Regenerative point technique in Markov-renewal process is applied to obtain the economic measures.     

Behaviour of a two-unit standby redundant system with imperfect switching and delayed repair

A 2-unit standby redundant system with imperfect switchover is considered. A repair facility is assumed to be available only at a fixed proportion of time. Failure-time distributions of units are exponential whereas repair-time distributions, distribution of time for the repairman to become available are general. The system has been investigated in detail by the help of semi-Markov process and closed form results are obtained for mean-time-to-system-failure, steady-state availability, expected number of occurrences of a state, expected profit and second moment of time in up state. Behaviour of several parameters has also been studied and several earlier models are included as particular cases.     

The reliability of a dynamic warm standby redundant system of n components with imperfect switching

A recursive formula is obtained for the reliability of a dynamic warm standby redundant system of n components with imperfect switching and constant failure rates. The formula is obtained using success modes analysis and is verfied for some known special cases.     

On a two-dissimilar unit standby redundant system with imperfect switch

In this paper we derive the L.T of the survivor function of the time to the first system failure, and the L.S.T of the distribution function of the time up to the first system failure. Finally we derive an asymtotic distribution for the time to system failure. The standby is cold (i.e. can not fail).     

On the switching mechanism in Rose Bengal-based memory devices

Impedance switching has been observed in many organic devices, but the mechanism is still a matter of debate. Reliable switch devices consisting of an organic layer of Rose Bengal derivatives sandwiched in between indium tin oxide and aluminum electrodes were fabricated. Modifying the chemical nature of the organic layers and visualizing the temperature distribution in the organic memory rule out several mechanisms. It is shown that the memory effect originates from filamentary switching.     

On profit evaluation in a two-unit maintained redundant system

A two-unit redundant system is considered and analytic expression for total expected profit earned in a given time is obtained after writing basic cost equations governing the behaviour of the system.A procedure is suggested to obtain optimal failure and repair rates so that expected steady state profit is maximum.     

Analytic study of a stand-by redundant equipment with switching and shelf life failures

An analytic study of a stand-by redundant equipment consisting of two components with imperfect switching-over device, has been carried out under the assumption that the stand-by component may fail during its shelf life. Time dependent probabilities of various states of the equipment have been obtained. The behaviour of the equipment under steady state has also been examined.     

Stochastic analysis of a two unit standby system with two switching devices and sliding preventive maintenance

A two unit standby (cold) system with two switches and sliding preventive maintenance policy is analysed. One switch is used to put the standby unit into operation, while the other is used to shift a failed unit into the repair facility. Switches may be found to fail at the time of need. P.M. of an on-line unit is performed while the other unit is in standby. Using regenerative point technique in Markov renewal process theory several reliability characteristics of interest to system designers and operations managers are obtained.     

Analysis of a repairable redundant system with delayed replacement

The paper deals with a redundant system with two types of spare units—a warm standby unit for instantaneous replacement at the time of failure of the active unit and a cold standby (stock) unit which can be replaced after a random amount of time. Failure time distributions of operative and standby units are exponential whereas all repair times follow arbitrary distributions. The system has been studied in detail by applying the results from the theory of semi-Markov process and mean-time-to-system-failure, steady-state availability, expected number of visits to a state, second moment of time in an up-state and expected profit of the system have been obtained.     

On a two-unit standby redundant system subject to repair and preventive maintenance

This paper derives the mean life and the Laplace-Stieltjes transform of the distribution of the first time to system-down for two dissimilar units standby redundant system with repair and preventive maintenance.Further, special cases of the results obtained here coincide with earlier results for the two-unit standby redundant system. The case when the system is not subject to preventive maintenance is considered as a particular case.     

Ion-implanted ESFI MOS devices with short switching times

Switching times of complementary MOS devices realized with epitaxial silicon films on insulators (ESFI) are reduced by using a self-aligning technique with ion implantation, since the gate overlapping capacitances and therefore the so-called Miller capacitances, are reduced thereby. Switching times and power dissipation have been measured using multistage ring oscillators. Stage-delay times of 500 ps at a supply voltage of 10 V (800 ps at 5 V), and power-delay products of 0.5 pJ at 5 V, have been obtained at five-stage ring oscillators with a channel length of about 3 /spl mu/m. Calculated and measured results are compared, and a simple formula for calculating the influence of the Miller capacitance on the switching times is indicated.     

On standby redundant system with repair,post repair and preventive maintenance

A two-unit standby system with repair, post repair and preventive maintenance (PM) is considered. The Laplace transform (LT) of survivor function (SF) of time to the first system failure (TFSF) and the mean are derived. Finally one theorem about the effect of (PM) is proved.     

Common-cause failure analysis of a redundant system with non-repairable units

This paper presents a newly developed generalized expression for mean time to failure, MTTF, of a non-repairable identical unit parallel system with warm standby and common-cause failures. Also presented is a modified version of this formula that takes into account the repairability of the warm standby and/or switching mechanism. Generalized expressions for system reliability and variance of time to failure are presented along with some tables and plots of system reliability and MTTF.     

Stochastic behaviour of a standby redundant system with three modes

This paper discusses the stochastic behaviour of a two-unit cold standby redundant system in which 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. Explicit expressions for the Laplace-Stieltjes transforms of the distribution function of the first passage time, mean time to system failure and steady state availability of the system are obtained. A few particular cases are discussed.