This article presents a perishable inventory system under continuous review at a service facility in which a waiting area for customers is of finite size M. We assume that the replenishment of inventory is instantaneous. The items of inventory have exponential life times. It is assumed that demand for the commodity is of unit size. The arrivals of customers to the service station form a Poisson...

We consider the single server constant retrial queue with a Poisson arrival process and exponential service and retrial times. This system has not waiting space, so the customers that find the server busy are forced to abandon the system, but they can leave their contact details. Hence, after a service completion, the server seeks for a customer among those that have unsuccessfully applied for ...

We consider the waiting time distribution of the Gl/Gl /1 queue where customers are served in random order; inter-arrival and service times may have finite or infinite variance. Our main result shows that the waiting time in heavy traffic can be written as a product of two random variables. Our proof is based on the intuitively appealing fact that in heavy traffic, the queue length stays consta...

We consider Markovian multi-server queues with two types of impatient customers: highand low-priority ones. The first type of customers has a non-preemptive priority over the other type. After entering the queue, a customer will wait a random length of time for service to begin. If service has not begun by this time he or she will abandon and be lost. We consider two cases where the discipline ...

This article presents a perishable inventory system under continuous review at a service facility in which a waiting area for customers is of finite size M . The authors assume that the replenishment of inventory is instantaneous. The items of inventory have exponential life times. It is assumed that demand for the commodity is of unit size. The service starts only when the customer level reach...

In this paper we analyse a queueing network consisting of parallel queues and arriving customers which have to be assigned to one of the queues. The assignment rule may not depend on the numbers of customers in the queues. Our goal is to find a policy which is optimal with respect to the long run average cost. We will consider two cases, holding costs and waiting times. A recently developed alg...