This paper analyzes anM/M/2 queueing systemwith two heterogeneous servers, one of which is always available but the other goes on vacation in the absence of customers waiting for service. The vacationing server, however, returns to serve at a low rate as an arrival finds the other server busy. The system is analyzed in the steady state using matrix geometric method. Busy period of the system is...

It is known that, given the observed tra c intensity ̂¡ 1, the expected value of the estimator ̂=(1− ̂) for the average number of customers =(1− ) in a stationary M=M=1 queueing model is in nite (Schruben and Kulkarni, Oper. Res. Lett. 1 (1982) 75–78). In this paper we generalize the above ndings to other system performance measures. Second, we show that, for the following four system performan...

We consider a system consisting of a single server serving a fixed number of stations. At each station there is an infinite queue of customers that have to undergo a preparation phase before being served. This model is connected to layered queueing networks, to an extension of polling systems, and surprisingly to random graphs. We are interested in the waiting time of the server. For the case w...

Many service providers use delay announcements to inform customers of anticipated delays. However, this information is usually not provided immediately, but rather after a short period of time (spent either waiting or occupied by the system). The focus of this paper is on the impact of this postponement on the ability of the firm to influence customer behavior by communicating non-verifiable co...

We consider a system consisting of a server alternating between two service points. At both service points there is an infinite queue of customers that have to undergo a preparation phase before being served. We are interested in the waiting time of the server. The waiting time of the server satisfies an equation very similar to Lindley’s equation for the waiting time in the GI/G/1 queue. We wi...

We consider a system consisting of a single server serving a fixed number of stations. At each station there is an infinite queue of customers that have to undergo a preparation phase before being served. This model is connected to layered queueing networks, to an extension of polling systems, and surprisingly to random graphs. We are interested in the waiting time of the server. For the case w...

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 ...

We consider a randomized policy to control the M/G/1 queueing system with an unreliable server, second optional service and general startup times. The server is subject to breaking down according to a Poisson process, and the repair time obeys a general distribution. All arrived customers demand the first required service, and only some of the arrived customers demand the second optional servic...

In this paper we present a componentwise delay measure for estimating and improving the expected delays experienced by customers in a multi-component inventory/ assembly system. We show that this measure is easily computed. Further, in an environment where the performance of each of the item delays could be improved with investment, we present a solution that aims to minimize this measure and, ...

We consider a network of parallel service stations each modelled as a single server queue. Each station serves its own dedicated customers as well as generic customers who are routed from a central controller. We suppose that the cost incurred by a customer is an increasing function of her time spent in system. In a significant advance on most previous work, we do not require waiting costs to b...