In a direct shipping (or point-to-point) network, individual deliveries are round trips from one supplier to one customer and back to either the same or another supplier, i.e., a truck can visit only one customer at a time before it has to return to a supplier. We consider the multiple sources/multiple sinks case, where a given set of direct deliveries from a set of suppliers to a set of customers must be scheduled such that the customer time windows are not violated, the truck fleet size is minimal, and the total weighted flow time is as small as possible. Direct shipping policies are commonly employed in just-in-time logistics (e.g., in the automotive industry) and in humanitarian logistics. We present an exact branch-cut-and-price algorithm for this problem, which is shown to perform well on instances from the literature and newly generated ones. We also investigate under what circumstances bundling suppliers in so-called supplier parks actually facilitates logistics operations under a direct shipping policy.

中文翻译：

---

在直接运输网络中使用时间窗口安排交货的分公司削减和价格

在直接运输（或点对点）网络中，个别交货是从一个供应商到一个客户，然后再返回到同一供应商或另一个供应商的往返行程，即一辆卡车在到达之前一次只能访问一个客户返回给供应商。我们考虑多源/多接收器的情况，其中必须安排从一组供应商到一组客户的一组给定的直接交付，以便不违反客户时间窗口，卡车车队规模最小，并且总加权流动时间尽可能小。直接运输政策通常用于即时物流（例如，在汽车行业）和人道主义物流。我们为这个问题提出了一个精确的分支切割和定价算法，这表明在来自文献的实例和新生成的实例上表现良好。我们还调查了在什么情况下将供应商捆绑在所谓的供应商园区实际上会促进直接运输政策下的物流运营。