In this paper we investigate a relatively simple deterministic four-class two-queue multiclass open network of single-server FIFO queues with traffic intensity one at each queue. Our purpose is to better understand the effect of feedback with class-dependent service times at the queues. The...

Abstract This paper describes the application of simple quality control charts to monitor the traffic intensity of single server queues, a still uncommon use of what is arguably the most successful statistical process control tool. These charts play a vital role in the detection of increases in...

Abstract The traffic intensity (ρ) is a vital parameter of queueing systems because it is a measure of the average occupancy of a server. Consequently, it influences their operational performance, namely queue lengths and waiting times. Moreover, since many computer, production and...

Queueing network models of computing systems are becoming increasingly popular because of their robustness and ease of solution. The impact of resource request patterning upon these models is presently not well understood. This paper proves the counter-intuitive fact that the effect of both...

The U.S. wind industry experienced a banner year in 2008, again surpassing even optimistic growth projections from years past. At the same time, the last year has been one of upheaval, with the global financial crisis impacting near-term growth prospects for the wind industry, and with federal...

This paper utilizes queuing models to analyze health care processes. We extend previous queuing models to allow for i) heterogeneous resources, ii) resource allocation to various tasks, and iii) teams (complementary resources). We model a process of one clinical unit. We use the model to analyze...

In this paper, we analyze a call center with impatient customers. We study how informing customers about their anticipated delays affects performance. Customers react by balking upon hearing the delay announcement and may subsequently renege, particularly if the realized waiting time exceeds the...

Although the norm in many retail banks is to serve customers on a first-come, first-served basis, some customers try to cut the line, usually by providing an excuse for their urgency. In other queues, however, this behavior is considered unacceptable and is aggressively banned. In all of these...

We consider an <i>M</i>/<i>M</i>/1 queueing system with impatient consumers who observe the length of the queue before deciding whether to buy the product. The product may have high or low quality, and consumers are heterogeneously informed. The firm chooses a slow or (at a cost) a fast service rate. In...

This paper studies outsourcing decisions for a two-level service process in which the first level serves as a gatekeeper for a second level of experts. The objective of the system operator (the client) is to minimize the sum of staffing costs, customer waiting costs, and mistreatment costs due...