scholarly journals Stochastic Analysis of a Two-Unit Cold Standby System Wherein Both Units May Become Operative Depending upon the Demand

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Reetu Malhotra ◽  
Gulshan Taneja
Keyword(s):  
Markov Processes ◽  
Stochastic Analysis ◽  
The Other ◽  
Regenerative Processes ◽  
Cold Standby ◽  
Standby System ◽  
Semi Markov Processes ◽  
System Effectiveness

The present paper analyzes a two-unit cold standby system wherein both units may become operative depending upon the demand. Initially, one of the units is operative while the other is kept as cold standby. If the operative unit fails or the demand increases to the extent that one operative unit is not capable of meeting the demand, the standby unit becomes operative instantaneously. Thus, both units may become operative simultaneously to meet the increased demand. Availability in three types of upstates is as follows: (i) when the demand is less than or equal to production manufactured by one unit; (ii) when the demand is greater than whatever produced by one unit but less than or equal to production made by two units; and (iii) when the demand is greater than the produces by two units. Other measures of the system effectiveness have also been obtained in general case as well as for a particular case. Techniques of semi-Markov processes and regenerative processes have been used to obtain various measures of the system effectiveness.

scholarly journals Reliability Electrical Power System of Hospital as Cold Standby System

2016 ◽  
Vol 37 (1) ◽  
pp. 153-168
Author(s):  
Franciszek Grabski
Keyword(s):  
Power System ◽  
Markov Processes ◽  
First Passage Time ◽  
Electrical Power ◽  
Random Variable ◽  
Time To Failure ◽  
Electrical Power System ◽  
Cold Standby ◽  
Standby System ◽  
Semi Markov Processes

Abstract The probabilistic model of a hospital electrical power system consisting of mains, an emergency power system and the automatic transfer switch with the generator starter are discussed in this paper. The reliability model is semi-Markov process describing two different units renewable cold standby system and switch. The embedded Semi-Markov processes concept is applied for description of the system evolution. Time to failure of the system is represented by a random variable denoting the first passage time of the process from the given state to the subset of states. The appropriate theorems of the Semi-Markov processes theory allow us to evaluate the reliability function and some reliability characteristics.

scholarly journals Semi-Markov reliability model of two different units cold standby system

2017 ◽  
pp. 1-1
Author(s):  
Franciszek Grabski
Keyword(s):  
Markov Processes ◽  
First Passage Time ◽  
Random Variable ◽  
Reliability Function ◽  
Passage Time ◽  
Time To Failure ◽  
Operation Process ◽  
Cold Standby ◽  
Standby System ◽  
Semi Markov Processes

A semi-Markov stochastic process is used for solving in a reliability problem in the paper. The problem concerns of two different component cold standby system and a switch. To obtain the reliability characteristic and parameters of the system we construct so called an embedded semi-Markov process in the process describing operation process of the system. In the model the conditional time to failure of the system is represented by a random variable denoting the first passage time from the given state to the specified subset of states. We apply theorems of the semi-Markov processes theory concerning the conditional reliability functions to calculate the reliability function and mean time to failure of the system. Often an exact reliability function of the system by using Laplace transform is difficult to calculate, frequently impossible. The semi-Markov processes perturbation theory, allows to obtain an approximate reliability function of the system in that case.

Stochastic analysis of a multi-unit cold standby system working in orbit form

1990 ◽  
Vol 30 (5) ◽  
pp. 845-850
Author(s):  
L.R. Goel ◽  
Rakesh Gupta ◽  
S.E. Moafi B
Keyword(s):  
Stochastic Analysis ◽  
Cold Standby ◽  
Standby System

Stochastic analysis of a two-unit cold standby system with two-stage repair and waiting time

Sankhya B ◽  
2010 ◽  
Vol 72 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Khaled M. El-Said ◽  
Mohamed S. El-Sherbeny
Keyword(s):  
Waiting Time ◽  
Stochastic Analysis ◽  
Two Stage ◽  
Cold Standby ◽  
Standby System

Analysis of a Standby System with Dissimilar Components and Imperfect Repair

2015 ◽  
Vol 6 (1) ◽  
pp. 64-77 ◽  
Author(s):  
Mohammed A. Hajeeh
Keyword(s):  
Steady State ◽  
Operating Systems ◽  
The Other ◽  
Repair Rate ◽  
Complete Replacement ◽  
Imperfect Repair ◽  
Cold Standby ◽  
Wear And Tear ◽  
Standby System ◽  
Selection Of

Operating systems do not perform their intended functions as time passes and ultimately fail due the failure of one or more of their parts, units, or components. Failure is caused by many factors such as age, deterioration, wear and tear, leakage, and lack of proper and timely maintenances. Failed components are usually replaced if not expensive or critical; otherwise repaired. Repair can be perfect, minimal, or imperfect; the selection of a specific repair option is dependent on the desire of the decision maker and the capability of the repairing staff/facilities. In this paper, imperfect repair is applied where a failed component is repaired several times before complete replacement. The system in this study consists of two dissimilar (non-identical) components, one in operation and the other in cold standby; each component has a different failure and repair rate depending on time spent in operation. The performance of the system is measured using steady state availability. A numerical example is presented to illustrate and compare the performance and cost of two versions of the system, the first version with two dissimilar components, and the second with two similar and new components.

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