Scientific paper ID 1602 : 2018/3

Kiril Karagyozov, Petya Stoyanova

The paper analyses the approach to implementing a simulation model of open network of queuing systems where individual queuing systems or their elements (queue or service devices) belong to subsystems (regions within the network) with limited total number of requests. There might be several such regions in an open network that may overlap. The developed simulation model of GPSS World is based on the model of open queuing system network in [1] as it has further developed blocks making possible to define the limited number of costumers per region and the membership of individual queuing systems or their elements to a region. An open queuing system network is examined receiving an input flow from the external environment with an arrival rate of customers λ0 costumers / per unit of time and a coefficient of variation of intervals between arrivals Ca0. The routing matrix Q is given with elements of probability the going out from the queuing system i to enter the queuing system j {qij}, i,j=0,K – К- number of queuing systems in the network. Service times tsj and their coefficients of variation Csj are given for each queuing system in the network. For each system a queue size limitation can be defined. The model is applied to an exemplary open network with two regions with limitations of the number of costumers: region 1, which 4 of the 5 queuing systems in the network belong to and region 2 including all 5 queueing systems. The incoming costumer waits at the network entrance when the number of customers in region 2 is equal to limitation. The results obtained illustrate the significant impact of limitations on the number of costumers as the coefficient of the total number increase in the network is significant, compared to a network without limitations. The results are analysed.

симулационни модели GPSS модели на мрежи от СМО смесени открити и затворени мрежи от СМО с ограничени буфериsimulation models GPSS models of queuing system networks mixed open and closed networks of queuing systems with limited buffersKiril Karagyozov Petya Stoyanova


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