A cost-based maritime container assignment model

A recently proposed frequency-based maritime container assignment model (Bell et al., 2011) seeks an assignment of full and empty containers to paths that minimises expected container travel time, whereas containers are in practice more likely to be assigned to minimise expected cost. A cost-based container assignment model is proposed here. It is assumed that routes and service frequencies are given so ship operating costs are also fixed. The objective is to assign containers to routes to minimise container handling costs, container rental and inventory costs. The constraints in the model are extended to include route as well as port capacities. It is shown that the problem remains a linear program. A numerical example is presented to illustrate the properties of the model. The paper concludes by considering the many applications of the proposed maritime container assignment model.     

An operational activity-based method to estimate CO2 emissions from container shipping considering empty container repositioning

This paper develops an operational activity-based method to estimate CO₂ emissions from container shipping in contrasts to the traditional aggregated activity-based method. Two case studies investigate the impacts of empty container repositioning policies and port handling capacity on CO₂ emission index. The results show that the aggregated method could well overestimate CO₂ emissions and the operational activity-based method is more appropriate. The paper also demonstrates that high port-handling capacity and efficient empty container repositioning could reduce CO₂ emissions in seaborne container transportation.     

Centralized versus distributed feeder ship service: The case of the Maasvlakte harbour area of Rotterdam

Coastal and inland feeder shipping is a critical factor for intercontinental container transport. The question is whether each intercontinental terminal should be equipped with its own service stations for feeder shipping, or whether pooling of the facilities would be more effective. For this paper, the service station examined for the service of feeder ships is equipped with two quay cranes operating in parallel supported by a small active quay stack. The centre for this feeder service consists of several of these stations. Simulation shows that a crane productivity of 96% is feasible with an average vehicle waiting time of 1 min, that a central service requires fewer service stations than a distributed service and that the quay transport for central and distributed transport requires the same number of terminal vehicles. The analysis shows that a centralized service is preferable, attracting 70% of the market potential.     

川藏铁路建设工程物流管理特征与体系

物流管理是川藏铁路建设工程的重要内容,与工程质量、工期、成本等目标密切相关。川藏铁路建设工程所需物资种类繁多,需求量大,运输及储备受到现场施工环境的制约,管理难度极大。因此,建立一套科学有效的川藏铁路物流管理体系对于铁路建设的精准实施具有重要保障作用。本文通过分析川藏铁路的物流特征,解析川藏铁路物流管理全要素,结合物流特征及研究方法构建了包含物资保障管理,物流运作管理,通道建设管理的川藏铁路建设物流管理体系。最后,针对川藏铁路物流管理中面临的矛盾与挑战,提出了相应的对策建议。     

A queuing model analysis of the performance of the Hong Kong container terminals

The growth of container‐handling industry and its impact on Hong Kong's economy have aroused considerable attention in recent decades. Within the recent twenty years, the rapid growth of container‐handling industry has led Hong Kong to become one of the world's busiest container port with over 11 million T.E.U. s (Twenty Feet Equivalent Units) container throughput in one year period. Also the container throughput is expected to reach 15.5 million T.E.U. s by year 2004.

As the success of container‐handling industry is significant, many studies have been conducted relating to this subject. In this paper, an application of a queuing theory model to Kwai Chung Container Terminals is developed and described. Specifically, we consider seasonal changes at the Terminals and focus on their effects on inter‐arrival time and service time of container vessel.

A crucial component of the study relates to the empirical data collected. Besides verifying the validity of the model, those data provide guidelines for developing schemes to manage the seasonal fluctuation of container throughput of the Terminals.     

An epsilon-optimal algorithm considering greenhouse gas emissions for the management of a ship’s bunker fuel

This paper provides an algorithm to minimize the fixed ordering, purchase, and inventory-carrying costs associated with bunker fuel together with ship time costs; and environmental costs associated with greenhouse gas emissions. It determines the optimum ship speed, bunkering ports, and amounts of bunker fuel for a given ship’s route. To solve the problem, we use an epsilon-optimal algorithm by deriving a property. The algorithm is illustrated by applying it to typical sample data obtained and the effects of bunker prices, carbon taxes, and ship time costs on the ship speed are analyzed. The results indicate that the ship speed and CO₂ emissions are highly sensitive to the factors considered.     

Storage space allocation in container terminals

Container terminals are essential intermodal interfaces in the global transportation network. Efficient container handling at terminals is important in reducing transportation costs and keeping shipping schedules. In this paper, we study the storage space allocation problem in the storage yards of terminals. This problem is related to all the resources in terminal operations, including quay cranes, yard cranes, storage space, and internal trucks. We solve the problem using a rolling-horizon approach. For each planning horizon, the problem is decomposed into two levels and each level is formulated as a mathematical programming model. At the first level, the total number of containers to be placed in each storage block in each time period of the planning horizon is set to balance two types of workloads among blocks. The second level determines the number of containers associated with each vessel that constitutes the total number of containers in each block in each period, in order to minimize the total distance to transport the containers between their storage blocks and the vessel berthing locations. Numerical runs show that with short computation time the method significantly reduces the workload imbalance in the yard, avoiding possible bottlenecks in terminal operations.     

新冠肺炎疫情对广州现代物流业的影响及对策探讨

广州是千年商都,是全国对外贸易及货物流动最活跃的地区,物流行业规模持续多年位居全国前列。2020年新冠肺炎疫情爆发以来,对广州的现代物流业发展带来了较大的影响和冲击。分析2020年上半年广州航空、航运、铁路、公路及邮政快递货运量变化及物流业发展面临的困境,探讨了广州现代物流业发展存在的弱项和短板,并在物流枢纽与网络、产业集聚及相关支持政策等方面提出了应对措施及建议。     

Energy-aware control for automated container terminals using integrated flow shop scheduling and optimal control

The performance of container terminals needs to be improved to handle the growth of transported containers and maintain port sustainability. This paper provides a methodology for improving the handling capacity of an automated container terminal in an energy-efficient way. The behavior of a container terminal is considered as consisting of a higher level and a lower level represented by discrete-event dynamics and continuous-time dynamics, respectively. These dynamics represent the behavior of a large number of terminal equipment. The dynamics need to be controlled. For controlling the higher level dynamics, a minimal makespan problem is solved. For this, the minimal time required by equipment for performing an operation at the lower level is needed. The minimal time for performing an operation at the lower level is obtained using Pontryagin’s Minimum Principle. The actual operation time allowed by the higher level for processing an operation at the lower level is subsequently determined by a scheduling algorithm at the higher level. Given an actual operation time, the lower level dynamics are controlled using optimal control to achieve minimal energy consumption while respecting the time constraint. Simulation studies illustrate how energy-efficient management of equipment for the minimal makespan could be obtained using the proposed methodology.