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...

Widening a highway toll plaza, border crossing or other checkpoint by adding travel lanes and vehicle-processing stations in parallel fashion can be expensive, and sometimes even infeasible. Rather than expanding laterally, checkpoint capacities can be increased by branching or staggering the...

We develop discrete time models for the throughput time distribution of orders arriving to a one-block warehouse. The models accommodate single- or multi-line orders, and we show how to use them to determine the optimal batch size, given a desired probability of on-time order fulfillment....

We consider the fluid model of a controlled birth-and-death process with an absorbing state. Instead of analyzing the trajectories, we investigate the performance functionals of the underlying process by considering algebraic equations of the dynamic programming type. We provide the accuracy of...

We consider the fluid model of a controlled birth-and-death process with an absorbing state. Instead of analyzing the trajectories, we investigate the performance functionals of the underlying process by considering algebraic equations of the dynamic programming type. We provide the accuracy of...