The Inventory Routing Problem (IRP) aims at determining the best distribution plan of a certain commodity from a supplier to a set of customers over a given planning horizon. Customers face a per period consumption and the plan has to be such that they can always satisfy it. The aim is to minimize the total cost of the distribution plan, which is given by the sum of routing and inventory holding cost. A replenishment strategy that has become common in the recent literature is the Maximum Level (ML) strategy, where no restriction is imposed on when the customers are visited and what the quantity delivered is, provided that a maximum inventory level at each customer (corresponding to the customer′s warehouse capacity) is not exceeded. This strategy is highly flexible and this clearly provides cost advantages. However, it might also create inconveniences to customers, who might receive visits when their inventory level is still relatively high. Towards addressing this issue, we study in this paper the Zero-Inventory-Ordering (ZIO) replenishment strategy for the IRP, where customers can be served only when their inventory level is zero. The aim is to analyze the impact of a policy which is more customer-orientedthan the ML.
DIABAT, A., BIANCHESSI, N. et ARCHETTI, C. (2024). On the zero-inventory-ordering policy in the inventory routing problem. European Journal of Operational Research, 312(3), pp. 1024-1038.