Associate Prof., Department of Mathematics, IEC College of Engg, Greater Noida
Online published on 25 December, 2015.
The present paper deals with the comparative study of two reliability models on a two-unit hot standby system wherein failures are unannounced. Initially, both the units are loaded but one of them is operative and the other is hot standby i.e. the total control of the machine is on the operative unit. Hot standby unit is hot in the sense that the latest information is transformed to it by the operative unit. The hot standby unit may also get failed. In the first model, the failure of a unit is not self announcing but it is revealed only when both the units get failed i.e. on the failure of the system whereas in the second model, the units are observed with regard to failures i.e. the failures are observable meaning thereby the failure of unit is detected as soon as it fails. Inspection is carried out for the failed unit to see as to whether it is repairable or irreparable and then it is repaired or replaced accordingly. Various measures of the system effectiveness are obtained by making use of semi-Markov processes and regenerative point technique. Study through graphs is also made.
