689 research outputs found

    Stochastic order results and equilibrium joining rules for the Bernoulli Feedback Queue

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    We consider customer joining behaviour for a system that consists of a FCFS queue with Bernoulli feedback. A consequence of the feedback characteristic is that the sojourn time of a customer already in the system depends on the joining decisions taken by future arrivals to the system. By establishing stochastic order results for coupled versions of the system, we establish the existence of homogeneous Nash equilibrium joining policies for both single and multiple customer types which are distinguished through distinct quality of service preference parameters. Further, it is shown that for a single customer type, the homogeneous policy is unique

    A Retrieval Queueing Model With Feedback

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    A multi-server retrial queuing model with feedback is considered in this paper.Input flow of calls is modeled using a Markovian Arrival Process (M AP) and the service time is assumed to follow an exponential distribution. An arriving call enters into service should there be a free server. Otherwise, in accordance to Bernoulli trials, the call will enter into an infinite orbit (referred to as a retrial orbit) to retry along with other calls to get into service or will leave the system forever. After obtaining a service each call, independent of the others, will either enter into a finite orbit (referred to as a feedback orbit) for another service or leave the system forever. The decision to enter into the feedback orbit or not is done according to another Bernoulli trial. Calls from these two buffers will compete with the main source of calls based on signals received from two independent Poisson processes.The rates of these processes depend on the phase of the M AP. The steady-state analysis of the model is carried out and illustrative numerical examples including economical aspects are presented

    Study of Queuing Systems with a Generalized Departure Process

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    This work was supported by the Bulgarian National Science Fund under grant BY-TH-105/2005.This paper deals with a full accessibility loss system and a single server delay system with a Poisson arrival process and state dependent exponentially distributed service time. We use the generalized service flow with nonlinear state dependence mean service time. The idea is based on the analytical continuation of the Binomial distribution and the classic M/M/n/0 and M/M/1/k system. We apply techniques based on birth and death processes and state-dependent service rates. We consider the system M/M(g)/n/0 and M/M(g)/1/k (in Kendal notation) with a generalized departure process Mg. The output intensity depends nonlinearly on the system state with a defined parameter: “peaked factor p”. We obtain the state probabilities of the system using the general solution of the birth and death processes. The influence of the peaked factor on the state probability distribution, the congestion probability and the mean system time are studied. It is shown that the state-dependent service rates changes significantly the characteristics of the queueing systems. The advantages of simplicity and uniformity in representing both peaked and smooth behaviour make this queue attractive in network analysis and synthesis

    (R1984) Analysis of M^[X1], M^[X2]/G1, G_2^(a,b)/1 Queue with Priority Services, Server Breakdown, Repair, Modified Bernoulli Vacation, Immediate Feedback

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    In this investigation, the steady state analysis of two individualistic batch arrival queues with immediate feedback, modified Bernoulli vacation and server breakdown are introduced. Two different categories of customers like priority and ordinary are to be considered. This model propose nonpreemptive priority discipline. Ordinary and priority customers arrive as per Poisson processes. The server consistently afford single service for priority customers and the general bulk service for the ordinary customers and the service follows general distribution. The ordinary customers to be served only if the batch size should be greater than or equal to a , else the server should not start service until a customers have accumulated. Meanwhile priority queue is empty; the server becomes idle or go for vacation. If server gets breakdown while the priority customers are being served, they may wait in the head of the queue and get fresh service after repair completion, but in case of ordinary customers they may leave the system. After completion of each priority service, customer may rejoin the system as a feedback customer for receiving regular service because of inappropriate quality of service. Supplementary variable technique and probability generating function are generally used to solve the Laplace transforms of time-dependent probabilities of system states. Finally, some performance measures are evaluated and express the numerical results

    Stability Condition of a Retrial Queueing System with Abandoned and Feedback Customers

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    This paper deals with the stability of a retrial queueing system with two orbits, abandoned and feedback customers. Two independent Poisson streams of customers arrive to the system, and flow into a single-server service system. An arriving one of type i; i = 1; 2, is handled by the server if it is free; otherwise, it is blocked and routed to a separate type-i retrial (orbit) queue that attempts to re-dispatch its jobs at its specific Poisson rate. The customer in the orbit either attempts service again after a random time or gives up receiving service and leaves the system after a random time. After the customer is served completely, the customer will decide either to join the retrial group again for another service or leave the system forever with some probability

    A Multi-class Bernoulli Feedback Queue with Gate Mechanism P.R.Parthasarathy ∗1 and K.Vasudevan †

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    We consider a single server queue in which multi-class customers arrive according to Poisson process and service times are exponentially distributed. The server works following a gate mechanism in which arriving customers do not enter service immediately and wait to form a batch. This batch of customers get service after the completion of service to the previous batch. We also assume that after the service time of all customers, a customer of one class may join the next batch to get the service of another or the same class. The number of customers in a batch, duration of service time to a batch and the probability for the busy period to end in finite time are obtained. Elegant expressions are obtained when there are only two classes. These results are extended to multi-class customers in a varying environment. The connections between queues and branching processes is exploited to obtain these results. Numerical illustrations are presented
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