COST-ANALYSIS OF THE R-UNLOADER QUEUING SYSTEM

This paper deals with an unloader queueing model in which N identical trailers are unloaded by one or more unloaders. Theoretical solutions are obtained with the assumption of negative exponential distributions for trip times, unloading times, and finishing times. A cost model is developed to determine the optimal number of trailers. In order to ev aluate the model robustness, simulation models are developed for three different distributions, exponential, second-order Erlang, and triang ular. We demonstrate, through simulation results, that the unloader qu eueing model is sufficiently robust to the variations of probability d istributions.