ABSTRACT
This chapter deals with three stochastic models A, B, and C, each consisting of two nonidentical units in standby network. One unit is named as the priority unit (p-unit) and the other as the nonpriority or ordinary unit (o-unit). In each model, the p-unit gets priority in operation over the o-unit. A single server is available to repair a failed unit and a failed repair machine (R.M.). The R.M. is required to do the repair of a failed unit. In models A and C, the o-unit gets priority in repair over the p-unit, whereas 7-2in model-B the priority in repair is also given to the p-unit over the o-unit. In each model it is assumed that the R.M. may also fail during its working and then the preference in repair is given to R.M. over any of the units. In models A and B, the failure and repair times of each unit are assumed to be uncorrelated independent random variables (r.vs.), whereas in model C these two r.vs. are assumed to be correlated having bivariate exponential distribution. In each model we have obtained various economic measures of system effectiveness by using the regenerative point technique.
