Research Article

Joint Optimization of Item and Pod Storage Assignment Problems with Picking Aisles’ Workload Balance in Robotic Mobile Fulfillment Systems

Table 3

The decision variables used in the J-IPSAP.

Decision variablesMeaningValue

If item is on layer of pod , it equals 1; otherwise, it equals 0
If order is fulfilled by pod , and is on pod , it equals 1; otherwise, it equals 0
If order is fulfilled by pod , it equals 1; otherwise, it equals 0
If pod is assigned to location , it equals 1, otherwise, it equals 0
The number of layers of pod with item
If the order is fulfilled by pod , and pod is allocated to location , it equals 1; otherwise, it equals 0