M service providers offer customers the choice of either waiting in a line or going offline and returning at a dynamically determined future time. The best-known example is the FASTPASS® system at Disneyland. To operate such a system, the service provider must make an upfront decision on how to allocate service capacity between the two lines. Then, during system operation, he must provide estim...

We investigate the use of priority mechanisms when assigning service engineers to customers as a tool for service differentiation. To this end, we analyze a nonpreemptive M/P H/c priority queue with various customer classes. For this queue, we present various accurate and fast methods to estimate the first two moments of the waiting time per class given that all servers are occupied. These wait...

We consider strategic arrivals to a FCFS service system that starts service at a fixed time and has to serve a fixed number of customers, e.g., an airplane boarding system. Arriving early induces a higher waiting cost (waiting before service begins) while arriving late induces a cost because earlier arrivals take the better seats. We first consider arrivals of heterogeneous customers that choos...

This study investigates a random N-policy Geo/G/1 queue with startup and closedown times. N is newly determined every time a new cycle begins. When random N customers are accumulated, the server is immediately turned on but is temporarily unavailable to the waiting customers. It needs a startup time before starting providing service. After all customers in the system are served exhaustively, th...

Besides service level and mean physical stock, customer waiting time is an important performance characteristic for an inventory system. In this paper we discuss the calculation of this waiting time in case a periodic review control policy with order-up-to-level S is used and customers arrive according to a Poisson process. For the case of Gamma distributed demand per customer, we obtain (appro...

We investigate the use of priority mechanisms when assigning service engineers to customers as a tool for service differentiation. To this end, we analyze a non-preemptive M/G/c priority queue with various customer classes. For this queue, we present various accurate and fast methods to estimate the first two moments of the waiting time per class given that all servers are occupied. These waiti...

This is the situation of interest in a trunked mobile system with priority, as the application of priorities is under heavy traffic: if the system is correctly sized, under regular load conditions no priorities are needed, as the waiting time must be low for all customers. For all delay probabilities the relative error of the mean waiting time for priority calls is no longer guaranteed to be lo...

Abstract: We consider a perishable inventory system with bonus service for certain customers, wherein the demand of a customer is satisfied only after performing some service on the item which is assumed to be of random duration. The maximum inventory level is S . The ordering policy is (0,S ) policy and the lead time is zero. The life time of each items is assumed to be exponential.The custome...

In this paper we consider a queuing system in which the service times of customers are independent and identically distributed random variables, the arrival process is stationary and has the property of orderliness, and the queue discipline is arbitrary. For this queuing system we obtain the steady state second moment of the queue size in terms of the stationary waiting time distribution of a s...