Integrated container fleet management in transportation service systems

海运集装箱在20世纪60年代首次引入。从那时起，班轮航运经历了一个高增长阶段，几乎独立于世界经济。集装箱航运市场的快速增长和全球化促使航运公司、港务局和物流代理等主要参与者之间的激烈竞争。为了在竞争中生存并获得更多业务，这些企业被迫采取创新、提高生产率和削减成本的战略。在业务层面上，一个非常重要的成本削减战略是高效和有效地管理集装箱船队。集装箱船队管理具有动态化、不确定性和需求不平衡等特点，是一个复杂的问题。动态化经营是航运业的本质。在客户需求和集装箱加工活动中存在不确定性，如拼装、移动、搬运、卸货、维护和维修。需求失衡是集装箱运输中一个尤为重要的问题。例如，在欧亚贸易路线上，欧洲港口的空箱过剩居高不下，而亚洲港口则面临严重短缺。集装箱船队管理中的重要决策包括船队规模、集装箱租赁、载重集装箱分配和空箱调运。这些决策关联度很高，应该谨慎管理。一方面，增加自有集装箱数量，租赁多余的集装箱，有效地重新定位空箱，可以增加服务能力，满足客户需求。另一方面，更大的船队规模会产生资本和维护成本；集装箱租赁会产生额外的租赁成本；而重新定位会产生额外的运输成本。差距1：文献中的大多数集装箱管理模型侧重于集装箱船队管理的一个组成部分(例如，空箱重新定位)。集装箱租赁要么被暗示，要么被忽视。它没有被视为一个明确的决策变量。申请人认为，明确将集装箱租赁决策与其他船队管理决策相结合是重要的，因为这将显著影响公司的动态运营，特别是在影响不可预测的随机情况下。因此，有必要建立一个包含随机情况下集装箱租赁决策的集装箱船队综合管理模型。差距2：现有的集装箱/车辆车队管理的数学规划模型需要在线计算、通信和数据。特别是，这类模型的基本逻辑通常对操作员隐藏。换句话说，集装箱/车辆调度策略的结构不直观。一些研究人员应用类似于库存控制理论中的(S，Q)策略的启发式规则来平衡地点之间的运输设备。然而，这种分散政策的次优性没有得到充分的研究，该政策只适用于某些特定的情况。因此，第二个差距是需要制定易于操作的集装箱管理政策并确定这些政策的最佳性。该项目的总体目标是开发一种能够处理集装箱船队管理的有效工具，其中包括以综合方式进行船队规模调整、租赁、配送和重新定位。该工具可以帮助机队经理确定易于操作和接近最优的策略。

Maritime containers were first introduced in the 1960s. Since then, liner shipping went through a high growth phase, almost independent of the world economy. The rapid growth and globalisation in container shipping market gave rise to intense completion among key players such as shipping lines, port authorities, and logistics agents. In order to survive competition and gain more business, these players are forced to adopt innovative, productivity enhancing and cost-cutting strategies. At an operational level, a very important cost-cutting strategy is to efficiently and effectively manage the container fleet. Container fleet management is complicated due to dynamic operation, uncertainty and demand imbalance. Dynamic operation is the nature of the shipping industry. Uncertainty exists in customer demands and container processing activities such as consolidation, movement, handling, discharge, maintenance and repair. Demand imbalance is a particularly important problem in container shipping. For example, on the Europe-Asia trade route, European ports are experiencing a high surplus of empty containers, while Asian ports are facing severe shortage. Important decisions in container fleet management include fleet sizing, container leasing, laden container distributing and empty container repositioning. These decisions are highly related and should be carefully managed. On the one hand, increasing the number of owned containers, leasing extra containers and effectively repositioning empty containers can increase service capacity and meet customer demands. On the other hand, larger fleet size incurs capital and maintenance costs; container leasing incurs extra leasing costs; while repositioning incurs additional transportation cost. Gap 1: The majority of container management models in the literature focused on one component of container fleet management (e.g. empty container reposition). Container leasing was either implied or ignored. It was not treated as an explicit decision variable. The applicant believes that explicitly integrating the container leasing decision with other fleet management decisions is important since it will significantly affect the company's dynamic operations, particularly in stochastic situations where the effect is unpredictable. Therefore, it is necessary to develop an integrated container fleet management model including container-leasing decision for stochastic situations. Gap 2: The existing mathematical programming models for container / vehicle fleet management have on-line computation, communication and data requirements. In particular, the underlying logic of such models is often hidden from the operators. In other words, the structures of the container / vehicle dispatching policies are not intuitive. Some researchers applied heuristic rules that resemble the (s, Q) policy in inventory control theory to balance transportation equipment among locations. However, the sub-optimality of such decentralised policy was not fully studied and the policy was only applicable to certain specific cases. Hence, the second gap is the need to develop easy-to-operate container management policies and establish their optimality. The overall objective of the project is to develop an effective tool that is able to deal with container fleet management that includes fleet-sizing, leasing, distributing and reposition in an integrated way. The tool can help fleet managers to identify easy-to-operate and near-to-optimal policies.