This paper deals with multi-server queueing system two kinds of Working Vacations (WVs) and impatient customers. A random timer is started whenever a customer comes into the system. The may abandon if service not completed before impatience expires. Each time after serving all customers, becomes empty then server begins 1st kind vacation. On returning from WV, 2nd WV has no When back either or ...

It is shown that a Markovian queue, with bulk arrivals and departures having any probability mass functions for their batch sizes, has geometrically distributed queue length at equilibrium (when this exists) provided there is an additional special bulk arrival stream, with particular rate and batch size distribution, when the server is idle. It is shown that the time-averaged input rate of the ...

Response time density is obtained in a tandem pair of Markovian queues with both batch arrivals and departures. The method uses conditional forward reversed node sojourn times derives the Laplace transform response probability function case that sizes are finite. result derived by generating takes into account path not overtake-free sense tagged task being tracked affected later at second queue...

In this paper, we consider a $$\text {Cox}/G_t/\infty $$ infinite server queueing model in random environment. More specifically, the arrival rate our is modeled as highly fluctuating stochastic process, which arguably takes into account some small timescale variations often observed practice. We prove homogenization property for system, yields an approximation by $$M_t/G_t/\infty queue with ef...

We investigate Markovian queues that are examined by a controller at random times determined Poisson process. Upon examination, the sets service speed to be equal minimum of current number customers in queue and certain maximum speed; this prevails until next examination time. study resulting two-dimensional Markov process length server speed, particular two regimes with time scale separation, ...

Queuing models provide an attractive and highly-efficient alternative to simulation for quantifying traffic flow efficiency. Stationary Markovian queuing models in which both inter-arrival times and service times are exponentially distributed have been studied by the National Airspace System (NAS). However, stationary queues cannot account for peaks and valleys in demand that are commonly obser...

Fairness is an inherent and fundamental factor of queue service disciplines in a large variety of queueing applications, ranging from computer systems, communications systems and call centers to airport and supermarket waiting lines. Service time variability across jobs is a major factor affecting both system performance and scheduling rules (for example, computer systems prioritize short jobs ...

We compare two approaches for a Markovian model in flexible manufacturing systems (FMSs) using Monte Carlo simulation. The model which is a development of Fazlollahtabar and Saidi-Mehrabad (2013), considers two features of automated flexible manufacturing systems equipped with automated guided vehicle (AGV) namely, the reliability of machines and the reliability of AGVs in a multiple AGV jobsho...