Article ID: | iaor20003106 |
Country: | South Korea |
Volume: | 24 |
Issue: | 2 |
Start Page Number: | 31 |
End Page Number: | 39 |
Publication Date: | Jun 1999 |
Journal: | Journal of the Korean ORMS Society |
Authors: | Kim Jeongseob |
Keywords: | M/D/s queues |
A new approximation method for finding the steady-state probabilities of the number of customers present in queueing systems with Poisson arrivals and two servers with different deterministic service times with infinite waiting room capacity is developed. The major assumption made for the approximation is that the residual service times of the servers have mutually independent uniform distributions with densities equal to the reciprocals of the respective service times. The method reflects the heterogeneity of the servers only through the ratio of their service times, irrespective of the actual magnitudes and difference. The transition probability matrix is established and the steady-state probabilities are found for a variety of traffic intensities and ratios of the two service times; also the mean number of customers present in the system and in the queue, and server utilizations are found and tabulated. The method was validated by simulation and turned out to be very sharp.