OPTIMIZATION OF NUMBER OF HOT STANDBY UNITS THROUGH RELIABILITY MODELS FOR A SYSTEM OPERATIVE WITH ONE UNIT

Hot standby systems are being used by various companies/industries/plants in order to avoid losses. However, use of too many hot standby units may be costlier and use of very less number of hot standby unit(s) may cause major losses. Thus, the study for taking decision regarding number of hot standby unit(s) becomes important in order to have optimum profit and hence the present paper develops three models for a system comprising one operative unit and no /one / two hot standby unit(s). To achieve the goal of optimizing the profit, the three models are compared finding out the cut-off points with regard to revenue, cost of installation of hot standby unit(s) and cost per visit of the repairman. Semi-Markov processes and regenerative point technique along with Laplace / Laplace Stieltjes transforms have been used to find various measures of system effectiveness.