R.K. Agnihotri

Analysis of a three-unit redundant system with two types of repair and inspection

Abstract This paper deals with a redundant system with two types of spare units—a warm standby unit for instantaneous replacement of a failed operative unit and a cold standby which takes a random amount of time to become operative/warm. After each repair a unit is sent for inspection to decide whether the repaired unit is perfect or imperfect. If the repaired unit is found to be imperfect then it goes for post-repair. Using the regenerative point technique in the Markov renewal process several reliability characteristics of interest to system designers and operation managers are obtained.

Two-unit redundant system with inspection and adjustable rates

Abstract A two-unit redundant system is studied, in which one unit is operative and the other is a warm standby which replaces the operative failed unit instantaneously. To increase system availability, the failure rate of the operative unit and the repair rate of the failed unit adjust automatically according to the state of the standby unit. Also, after repair of the operative failed unit it is sent for inspection to decide whether the repaired unit is perfect or not. If the repaired unit is found to be imperfect, it is sent for post repair. Using a regenerative point technique in the Markov renewal process, several reliability characteristics of interest to system designers and operation managers are obtained.

Two-non-identical unit-system with priority-based repair and inspection

The present paper deals with the analysis of a system consisting of two non-identical parallel units, in which the first type of unit has priority over the second type for repair, inspection and post repair. The failure rates, and the repair, inspection and post repair time distributions for both types of units are assumed to be different. Using the regenerative point technique in the Markov-renewal process, several reliability measures are obtained.

Profit evaluation of a two unit cold standby system with random change in units

Abstract A two unit cold standby system with single repair facility is considered. For achieving high reliability of the system, the operative and the standby units are interchanged at random epochs. After the repair, the unit is sent for inspection to decide whether the repair is satisfactory. In case the repair is found unsatisfactory the unit is again sent for post repair. Using a regenerative point technique, various measures of system effectiveness are obtained.

Stochastic analysis of a two-unit redundant system with two types of failure

Abstract The present paper investigates a stochostic model of a two-unit warm standby system with a single repair facility. Before repair, the failed unit is sent for fault detection to decide whether it failed due to machine defect or critical human error. The probability of having machine defect and C.H.E. has been fixed. Using the regenerative point technique in the Markov renewal process various measures of system effectiveness are obtained.

Analysis of a two unit redundant system with optimum interchangement time

Abstract By considering a two unit cold standby system with single repair facility, we in the present paper give an analytical approach for finding optimum interchangement time of units for giving rest to the operative unit. In this paper, for attaining increased reliability of the system, the operative and the standby units are interchanged after the optimum interchangement time.

Stochastic analysis of a two unit warm standby system with fault detection and inspection

Abstract This paper deals with a two unit redundant system in which one unit is operative and the other is warm standby, i.e. the standby unit is used to replace the operative failed unit instantaneously. Before the repair of the operative failed unit, it is sent for fault detection which takes a random amount of time. After the repair, the unit goes into inspection for deciding whether the repair is perfect or not. If the repair is found to be imperfect the unit is sent for post repair. Using the regenerative point technique in the Markov renewal process several reliability characteristics of interest to system designers and operation managers are obtained.

A single-server two-unit warm standby system with n failure modes, fault detection and inspection

Abstract A stochastic model of a two-unit warm standby system with n failure modes of each unit is investigated. Before repair, the failed unit is examined for the type of fault, which decides the failure mode. This process needs a random amount of time. After repair, the unit is inspected to decide whether the repair is perfect or not. If the repair is found to be imperfect, the unit is sent for post-repair. Using a regenerative point technique in the Markov renewal process, several reliability characteristics of interest are obtained.

Two non-identical operative unit system with repair and inspection

Abstract The present paper deals with the analysis of a system consisting of two non-identical parallel units. The failure rates, and the repair, inspection and post repair time distributions for both the units are also assumed to be different. Using regenerative point technique in the Markov renewal process, several reliability characteristics of interest are obtained.

Stochastic analysis of a redundant system with two types of failure

Abstract This paper deals with the analysis of a system model consisting of two units, in which one is operative and the other is on cold standby. The failure of an operative unit may be caused by a machine as well as by random shocks which occur after a certain interval of time. Using the regenerative point technique in Markov renewal processes, several effective measures of reliability are obtained.