Logistics and Transportation in Supply Chains

供应链中的物流与运输

• 批准号: RGPIN-2014-04277
• 负责人: Bookbinder, James
• 金额: $ 1.6万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=566414
• 关键词: Logistics; Transportation; Supply; Chains

SHIPMENT CONSOLIDATION (SCL) is the purposeful combination of several small loads, for dispatch together, as a single larger shipment. Although delay of order deliveries may incur a cost, SCL can lead to significant economies of scale in transportation, thus reducing the overall system cost. Service to the receiver of the goods need not be degraded, if attention is paid to the maximum holding time (length of the consolidation cycle). The shipper wishes to select an appropriate consolidation policy that determines the right moment to terminate the accumulation process and dispatch a load. Our new work aims to propose and study policies that are more general than the typical ones that are based solely upon the aggregate shipment weight and/or the maximum holding time. Our new models are capable of recording more information about the order-accumulation process (e.g. delays of individual orders), thus permitting consideration of policies dependent on such information. We will also improve the accuracy of our models by considering Markovian arrival processes that go beyond the typically-assumed Poisson distribution, and by incorporating potential correlations between the arrivals of consecutive orders and their weights. Continuing our recent success with the Matrix-Analytic method, we will develop efficient solution techniques to obtain accurate results. We will employ a more realistic cost structure: a delay penalty cost (customer disutility of waiting) that is strictly increasing in that waiting time. The ultimate goals are to identify the form of the optimal policy for the general case, and to construct efficient algorithms to determine the parameters of that optimal policy, for a consolidation process involving orders of multiple products whose transport costs and/or delay-penalty rates may differ. LOT-SIZING PROBLEMS seek to determine the timing and replenishment quantities, of a single item or of several items, to minimize total costs while meeting demand requirements. Demand, based on orders from customers, can be satisfied through the production and distribution when those items are grouped into families. The joint coordination via families recognizes the sharing of a resource in transportation (as in SCL) or in the manufacturing portion of the supply chain. Our research in the study of lot-sizing of several multi-product families is new in the production context. This work will also shed light on coordinated inventory control of products ordered from a common supplier. We will explore various strong reformulations for the multi-family lot-sizing problem, and test new heuristics to speed up solution times, maintaining solution quality. THE INVENTORY-ROUTING PROBLEM concerns both vehicle routing (the sequencing of customers in making deliveries by truck) and the management by the vendor of stocks for those customers whose products are being delivered. Our research allows, when advantageous, the development of indirect routes. These serve logically-grouped sets of customers that receive goods through a given cross-dock (CD). There can be as many customers on the routes as permitted by vehicle capacity. Both the inventory holding costs at customers and the pipeline stocks are considered. This theme extends, in a non-trivial way, the applicant’s previous publications on VMI (Vendor Managed Inventory) and cross-docking. We hope to obtain general, provably near-optimal results, and an efficient solution algorithm, for a system containing several CDs in which distinct products from multiple suppliers are delivered by a private fleet on routes to various customers. This work will represent one of the very first such models.

装运合并（SCL）是有目的的组合几个小负载，为调度一起，作为一个单一的较大的货物。虽然延迟交付订单可能会产生成本，但SCL可以带来显著的运输规模经济，从而降低整体系统成本。如果注意到最大持有时间（合并周期的长度），对货物接收者的服务不需要降级。托运人希望选择一个适当的合并策略，以确定终止累积过程和调度负载的正确时刻。我们的新工作旨在提出和研究比仅基于总运输重量和/或最大持有时间的典型政策更通用的政策。我们的新模型能够记录更多关于订单积累过程的信息（例如单个订单的延迟），从而允许考虑依赖于这些信息的策略。我们还将通过考虑超出通常假设的泊松分布的马尔可夫到达过程，以及通过合并连续订单到达与其权重之间的潜在相关性，来提高模型的准确性。继续我们最近在矩阵分析方法上的成功，我们将开发有效的解决技术来获得准确的结果。我们将采用更现实的成本结构：延迟惩罚成本（客户等待的负效用）在等待时间内严格增加。最终目标是确定一般情况下最优策略的形式，并构建有效的算法来确定该最优策略的参数，用于涉及运输成本和/或延迟惩罚率可能不同的多种产品订单的合并过程。批量问题寻求确定单个或多个项目的时间和补充数量，以在满足需求的同时最小化总成本。需求，基于客户的订单，可以通过生产和分配，当这些项目分组成家庭来满足。通过家庭的联合协调承认在运输（如SCL）或供应链的制造部分共享资源。我们对多产品族的批量研究在生产环境中是新的。这项工作还将阐明从共同供应商订购的产品的协调库存控制。我们将探索多家庭批量问题的各种强重构，并测试新的启发式方法，以加快解决时间，保持解决质量。库存路线问题既涉及车辆路线（用卡车运送货物的客户顺序），也涉及供应商对正在运送产品的客户的库存管理。我们的研究允许在有利的情况下发展间接路线。它们服务于逻辑分组的客户组，这些客户组通过给定的交叉码头（CD）接收货物。在车辆容量允许的范围内，路线上可以有尽可能多的客户。同时考虑了客户库存持有成本和管道库存。这个主题以一种重要的方式扩展了申请人以前关于VMI（供应商管理库存）和交叉对接的出版物。对于一个包含多个cd的系统，我们希望得到一般的、可证明的接近最优的结果，以及一个有效的解决算法，在这个系统中，来自多个供应商的不同产品由私人车队在航线上交付给不同的客户。这项工作将代表最早的这种模型之一。