Stochastic behaviour of a two-unit standby system with two types of repairmen and patience time

Stochastic behaviour of a two-unit cold standby redundant system, with two types of repairmen is analysed. The first repairman (usually called "regula r" repairman) will always remain with the repair facility, with the known f act that he might not be able to do some complex repair within some tolerab le (patience) time. An expert repairman is called to the system if and only if the regular repairman is unable to do the job, within some fixed time o r on system failure, whichever occurs first. Techniques of regenerative poi nt processes have been used to obtain various measures of system effectiven ess and thereby profit incurred. The time-dependent availability, steady-st ate availability, reliability, Mean Time To Failure (MTTF), and profit func tion are obtained numerically and graphs are also drawn. (C) 1998 Elsevier Science Ltd. All rights reserved.