Optimizing the workload allocation in an e-fulfillment center using queueing theory

In this study, we propose an approach to release pick batches to the warehouse of an e-fulfillment center, that takes into account the workload throughout the entire process. This approach is based on methods from queueing theory and involves some linear programming as well. In order to investigate whether the proposed approach performs better than the current approach, a mathematical model is formulated and for validation purposes a simulation model was created as well. The performance of the current and the proposed approach are assessed on the average throughput, sojourn time and work in progress. The results of the simulation model show that, with a significance level of 1%, the proposed approach performs significantly better than the current approach. However, the formulated mathematical model turns out to capture the logic behind the processes in the warehouse insufficiently enough to accurately determine the performance measures. Further research is required to adjust the mathematical model such that the gap between the model and practice becomes smaller.