Queuing modeling is the mathematical approach for the analysis of waiting lines. The central problem in every queueing model is a trade-off decision: The manager must weigh the added cost of providing more rapid service against the inherent cost of waiting. In this paper, a new fuzzy approach to...

We consider two reverse logistics systems where returned products are as good as new. For the first system, the product return flow is independent of the demand flow. We prove that the optimal policy is of base-stock type and we establish monotonicity results for the optimal base-stock levels,...

The multidimensional stock control that functions in a random Markov environment is considered. The mathematical formalization of this model was considered with the use of sums of the random variables defined on the Markov chains. The authors introduce a definition of risk function of the type...