Analysis of a stochastic model of a standby system with substandard unit and correlated life time

This model deals with a stochastic model of two dissimilar units, one is of good quality and other substandard one. The substandard unit may be repaired or may be replaced by the other substandard unit depends upon the cost of replacement. If a unit becomes operative, it remains operative till it fails. On failure of a unit, a repairman comes immediately to repair it and lifetimes are correlated. Various measures of performances of the system are obtained by Semi-Markov process and Regenerative point techniques. Numerical results and graphs pertaining to a particular case also included.