MAP/G/l QUEUES UNDER N-POLICY WITH AND WITHOUT VACATIONS

This paper considers MAP/G/1 queueing systems under the following two situations: (1) At the end of a busy period, the server is turned off and inspects the queue length every time a customer a,rrives. When the queue length reaches a pre-specified value N , the server turns on and serves customers continuously until the system becomes empty. (2) At the end of a busy period, the server takes a sequence of va.cations. At the end of ea,ch va.cation, the server inspects the queue length. If the queue length is greater than or equa,l to a pre-specified value N at this time, the server begins to serve customers continuously until the system becomes empty. For ea.ch case, we analyze the stationary queue length and the actual wa,iting time distributions, and derive the recursive formulas to compute the moments of these distributions. Furthermore, we provide a numerical algorithm to obtain the mass function of the stationary queue length. The numerical exa,mples show tl1a.t in light traffic, correlation in a,rrivals leads to a smaller mean waiting time.