Cognitive radio has become a promising technology to increase spectrum utilization through spectrum sharing between licensed users (primary users) and unlicensed users (secondary users). Performance evaluation and analysis is of key importance to get more knowledge of this newly emerged technology. Queueing theory and Markov chain model have been applied to conduct the analysis, where some resu...

This paper considers the comparison of two ðs; SÞ production inventory systems with retrials of unsatisfied customers. The time for producing and adding each item to the inventory is exponentially distributed with rate b. However, a production rate ab higher than b is used at the beginning of the production. The higher production rate will reduce customers’ loss when inventory level appro...

I n a call center, staffing decisions must be made before the call arrival rate is known with certainty. Once the arrival rate becomes known, the call center may be over-staffed, in which case staff are being paid to be idle, or understaffed, in which case many callers hang-up in the face of long wait times. Firms that have chosen to keep their call center operations in-house can mitigate this ...

This paper studies the single server repairable queueing system with variable service rate and failure rate. The rule of variation is that changes when number customers in reaches a certain value. may fail at any time, rates idle periods busy are different. has one reliable repairman to repair server. steady-state joint distribution states obtained by matrix geometric solution method, availabil...

New diseases have always been part of humanity’s world, and some them had created severe threat to human kind challenge the researchers medical practitioners. The deadly novel coronavirus SARS-CoV-2 (severe acute respiratory syndrome- -2) said be COVID-19, name given by WHO on February 11, 2020, is presently most disastrous infectious disease. In present paper our basic objective assess risk sp...

The main theme of this paper is to find the Distributed Data Transaction of an Apache web server using bulk service rule. We obtain the parameter of service rate, Arrival rate, Expected waiting time and Expected Busy period. The inter arrival and inter service of HTTP request is assumed to Poisson Distribution Process (PDP) and these events are considered in the server for process sharing. The ...

In order to implement the cellular manufacturing system in practice, some essential factors should be taken into account. In this paper, a new mathematical model for cellular manufacturing system considering different production factors including alternative process routings and machine reliability with stochastic arrival and service times in a dynamic environment is proposed. Also because of t...

Motivated by large-scale service systems, we consider an infinite-server queue with batch arrivals, where the service times are dependent within each batch. We allow the arrival rate of batches to be time-varying as well as constant. As regularity conditions, we require that the batch sizes be i.i.d. and independent of the arrival process of batches, and we require that the service times within...

This paper presents a queuing analysis-based method for modeling the 24-h charging load profile of plug-in electric vehicle (PEV) station. The model considers arrival PEVs as non-homogeneous Poisson process with different rates over day. first PEV assumes customer convenience factor that influences hourly rate vehicles at station, while second is developed assuming customers would respond to pr...