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...

We study the M_t /G/\infty queue where customers arrive according to a sinusoidal function \lambda _t = \lambda + A sin(2\pi t/T) and the service rate is \mu . We show that the expected number of customers in the system during peak congestion can be closely approximated by (\lambda + A)/\mu for...

The following example illustrates the problem treated in this paper: Two gas stations are located one after the other on a main road. A driver who needs to fill his rank sees the queue situation at the first station but not at the second one. The driver estimates the expected waiting time at the...

To provide useful practical insight into the performance of service-oriented (non-revenue-generating) call centers, which often provide low-to-moderate quality of service, this paper investigates the efficiency-driven (ED), many-server heavy-traffic limiting regime for queues with abandonments....

Stochastic Economic Lot Scheduling Problems (ELSPs) involve settings where several items need to be produced in a common facility with limited capacity, under significant uncertainty regarding demands, unit production times, setup times, or combinations thereof. We consider systems where some...

In a G/G/c/N system (a queue with general distributions of inter-arrival and service time, c servers and N - c \ge 0 queueing positions), let B be the steady-state probability that an arriving customer finds all queue positions filled and p be the time average probability that all queue...

In this paper we describe the mean number of busy servers as a function of time in an M_t/G/\infty queue (having a nonhomogeneous Poisson arrival process) with a sinusoidal arrival rate function. For an M_t/G/\infty model with appropriate initial conditions, it is known that the number of busy...

Applying the technique of smoothed perturbation analysis (SPA) to the GI/G/m queue with first-come, first-served (FCFS) queue discipline, we derive sample path estimators for the second derivative of mean steady-state system time with respect to a parameter of the service time distribution. Such...