The present investigation deals with a machine repair problem consisting of cold and warm standby machines. The machines are subject to breakdown and are repaired by the permanent repairman operating under N-policy. There is provision of one additional removable repairman who is called upon when the work load of failed machines crosses a certain threshold level and is removed as soon as the wor...

This study is concerned with the performance modeling of a fault tolerant system consisting of operating units supported by a combination of warm and cold spares. The on-line as well as warm standby units are subject to failures and are send for the repair to a repair facility having single repairman which is prone to failure. If the failed unit is not detected, the system enters into an unsafe...

We consider an M/G/∞ exchangeable-item repair system with spares and ample servers to which arriving customers bring failed items for repair. The system comprises a multi-item-type, multiechelon system in which failed items may be either repaired at the first echelon or sent for repair in higher echelons. To decrease the average waiting time of a random customer, managers can invest in multiple...

In many industrial situations, machines are subjected to random breakdowns. In this paper, we consider the asynchronous vacation policy for the multi-server machine repair problem with server breakdown and two types of spares. According to this policy, when a certain number of servers become idle at a service completion instant, the servers will take an asynchronous vacation of random length to...

In this paper, we analyze a machine repairable system with warm spares and two repairmen. The first repairman never takes vacations. The second repairman leaves for a vacation of random length when the number of the failed units is less than N. At the end of a vacation period, this repairman returns back if there are N or more failed units accumulated in the system. Otherwise this repairman goe...

Abstract: The present investigation deals with the multi component machine repair problem by including the concepts of reneging and interdependent controlled rates. We consider a machining system consisting of M operating units, S1 and S2 warm spares of two kinds and a repair facility having R permanent repairmen and r additional removable repairmen. When all the spares are used and the operati...

The present investigation presents a stochastic model for a flexible manufacturing system consisting of flexible machine, loading/unloading robot and an automated pallethandling device. We consider unreliable flexible manufacturing cell (FMC) wherein machine and robot operate under individual as well as common cause random failures. The pallethandling system is completely reliable. The pallet o...

this paper analyzes a controllable discrete-time machine repair problem withl operating machines and two repairmen. the number of working servers can be adjusteddepending on the number of failed machines in the system one at a time at machine's failure orat service completion epochs. analytical closed-form solutions of the stationary probabilities ofthe number of failed machines in the sys...