New approaches for inference of unobservable queues

Many inference methods of queueing systems have been developed on the basis of Larson´s QIE(queue inference engine) with the assumption of homogeneous Poisson arrivals. It inferred the queueing systems with starting and ending times of service. However, the arrival processes are becoming complex lately, so there are some limits to apply the method. Our study introduces new methods of queue inference which can find the internal behaviors of queueing systems with only external observations, arrival and departure time. This study deals with general GI/G/c queueing systems: (a) FCFC (first come first served); (b) LCFS (last come first served); (c) RSS (random selection for service). The accurate inferences were obtained from FCFS and LCFS systems, and the approximate solutions from RSS systems.