Optimal planning for distribution networks of perishable products is addressed by means of a two-step approach pursuing both strategic and tactical goals. The distribution network is represented as a directed graph, and discrete-time dynamic equations are devised to model the storage and transportation of products. The first decision step consists of an optimization problem to account for a strategic viewpoint. In particular, this problem allows to select optimal values for replenishment cycles of products, safety stocks, and amounts of products to be transferred among the nodes of the network by considering uncertainty on long-term demand predictions. The second decision step requires the solution of rolling-horizon optimization problems at the various time buckets that exploit accurate, short-term predictions of customers' demands according to a tactical perspective. In this case, the strategic decisions on the amounts of products to be transferred are tuned according to the available short-term predictions of demands. The effectiveness of the proposed approach is showcased by simulations in a case study, in comparison with a classical lot-for-lot strategy.

中文翻译：

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易腐产品配送的两步优化模型

通过追求战略和战术目标的两步方法来解决易腐产品分销网络的最佳规划。分销网络表示为有向图，并设计了离散时间动态方程来模拟产品的存储和运输。第一个决策步骤包括考虑战略观点的优化问题。特别是，该问题允许通过考虑长期需求预测的不确定性，为产品的补货周期、安全库存和要在网络节点之间转移的产品数量选择最佳值。第二个决策步骤需要在不同的时间段解决滚动优化问题，这些时间段利用客户的准确、短期预测 从战术角度提出要求。在这种情况下，将根据可用的短期需求预测调整有关要转移的产品数量的战略决策。与经典的逐批策略相比，所提出方法的有效性通过案例研究中的模拟来展示。