We consider a finite-population queueing system with heterogeneous classes of customers and a single server. For the case of nonpreemptive service, we fully characterize the structure of the server’s optimal service policy that minimizes the total average customer waiting costs. We show that the optimal service policy may never serve some classes of customers. For those classes that are served,...

Abstract. We consider a two-priority, preemptive, single-server queueing model. Each customer is classified into either a high priority class or a low priority class. The arrivals of the two priority classes follow independent Poisson processes and service time is assumed to be exponentially distributed. A queue-length-cutoff method is considered. Under this discipline the server responds only ...

The subject of this paper is a mechanism that allows customers to overtake others. In our system, customers observe the queue length upon arrival, and have the option of overtaking some or all of the customers already present in the queue. Overtaking is associated with a fixed price per overtaken customer. If a customer chooses to overtake some but not all of the present customers, he overtakes...

We analyze queueing model with priority scheduling by supplementary variable method. Customers are classified into two types ( type-1 and type-2 ) according to their characteristics. Customers of each type arrive by independent Poisson processes, and all customers regardless of type have same general service time. The service order of each type is determined by the queue length of type-1 buffer...

A new model and solution for the energy minimizing vehicle routing problem with time windows (EVRPTW) and customers’ priority is presented in this paper. In this paper unlike prior attempts to minimize cost by minimizing overall traveling distance, the model also incorporates energy minimizing which meets the latest requirements of green logistics. This paper includes the vehicles load as an ad...

In cycle of attraction and keeping the customers, fulfilling the customer satisfaction via identifying of their needs is very important. So, identifying the amount of customer satisfaction and informed of the field of strength and weakness in this regard, helps manager programming in line with customers better maintenance. The objective of this study is determination and priority of effecting c...

In this paper, we study a queueing system serving multiple classes of customers. Each class has a finite-calling population. The customers are served according to the preemptive-resume priority policy. We assume general distributions for the service times. For each priority class, we derive the steady-state system size distributions at departure/arrival, and arbitrary time epochs. We introduce ...