Many companies configure their warehouse with a forward area and a reserve area. The former is used for efficient order-picking, the latter for replenishing the forward area. We consider a situation in which orders are picked during a certain time period, referred to as the picking period. Prior to the picking period there is sufficient time to replenish the forward area. Our objective is to determine which replenishments minimize the expected amount of labor during the picking period. Further, we present a second model with a constraint on the replenishment activity. We model the problem as a binary programming problem and present efficient heuristics that provide tight performance guarantees. We compare the heuristics with procedures that are popular in practice and show that significant labor-savings are possible.
- Linear Programming
- Integer Programming