Objective: In this study we consider a two-state retrial queueing system with feedback having two identical parallel servers. Transient state probabilities for exact number of arrivals and departures from the will be obtained when both, one or none servers is busy. Numerical graphical solutions also obtained. Methods: The difference-differential equations governing are solved recursively, Lapla...

Consider a single server retrial queueing system with preemptive priority service and single working vacation in which two types of customers arrive in a Poisson process with arrival rates λ1 for low and λ2 for high priority customers. We assume that regular service times follow an exponential distribution with parameters μ1 and μ2 correspondingly. The retrial is introduced for low priority cus...

In the planning of modern cellular mobile communication systems customer behavior has to be carefully taken into account In this paper two models dealing with the call retrial phenomenon are presented The rst model considers a base station with a nite customer population and repeated attempts A Markov chain modeling is proposed and a recursive solution of the state probabilities is presented Th...

Abstract. A batch arrival retrial queue with general retrial times, state dependent admission, modified vacation policy and feed back is analysed in this paper. Arrivals are controlled according to the state of the server. If the orbit is empty, the server takes at most J vacations until at least one customer is received in the orbit when the server returns from the vacation. At the service com...

Retrial systems have been used extensively to model many practical problems in call center, data cloud service computing center and computer network system. This paper deals with a multi-server retrial system the features of imperfect coverage delay reboot. In investigated system, arrivals may not be detected because some fault issues. When this situation happened, is cleared by reboot operatio...