Approximations for Networks of Queues with Overtime

This paper presents simple approximations for networks of queues with overtime operation at some stations. This type of network is commonly encountered in several manufacturing applications. We provide bounds on the performance of the approximations for single and multiple machine stations. Our results suggest that the methods perform satisfactorily. These approximations can be used in conjunction with parametric decomposition methods to analyze queueing networks. The computational results indicate that the performance of the decomposition approach does not deteriorate when combined with the methods proposed in this paper.