基于一个二维水弹塑性方法和极限强度评估的集装箱船结构优化研究

海上极端波过去常常导致船舶结构的极限破坏,而船舶的极限崩溃涉及到船体结构的动态极限强度和结构非线性.该文通过二维的水弹塑性方法研究了集装箱船在极端波中的非线性动态强度,该方法考虑了船体的极限强度以及船体结构的非线性和波浪之间的耦合.并通过该二维水弹塑性方法和极限评估方法研究了船体结构的结构优化.文中还通过二次规划法(SQP)来优化基于非线性的动态强度的集装箱船体结构.最少的结构成本是本优化的目标函数,约束条件保证船体的强度要小于结构的极限强度,并且结构设计尺寸要满足规范的要求.随着设计波高的变化,这些优化的设计变量的变化趋势得以发现,一些研究的结论可用于船舶规范的参考.     

Heuristic estimation of container stacking and reshuffling operations under the containership delay factor and mega-ship challenge

This paper addresses a highly researched area, the reshuffling problem in ports, using a new paradigm-modified containership service order in light of credit risk assessment. Container stacking and reshuffling operations can cause ship delays and additional risk. In deep-sea terminals, outbound containers are tightly stacked according to the retrieval sequence. Due to lack of space, terminals stack containers in multiple tiers. This means any delay in the arrival of a ship can impose extra handlings and reshuffling of containers delaying future cargo handling. This paper addresses the reshuffling problem with a concept similar to the credit scoring and rating of creditworthiness used in the banking industry. By utilizing this comparison to the banking credit risk concept, a heuristic estimation model is proposed that illustrates the side effects of unscheduled modifications in containership service order. Further, the mega-ship trend amplifies the reshuffling debate. Probability of delay, reshuffles given delay, and call size at delay are introduced as the three-point risk metrics of the model. Numerical simulations illustrate the functionality to develop terminal stacking strategies as well as emphasize the mega-ship phenomenon and its side effects on terminals (i.e. yard operation deadlock).     

集装箱船舶实配过程的遗传算法解决策略

本文基于模糊优选的多目标优化遗传算法和隔离小生境技术的多峰函数优化遗传算法,建立了集箱船舶实配模型。计算机模拟的结构表明,计算结果符合工程要求,具有推广应用价值。     

Examining quick delivery at an affordable cost by the NSR/SCR-combined shipping in the age of Mega-ships

ABSTRACT

The Mega-ships, the maximum containerships represented by 20,000TEU-class (LOA:400m, Breadth: 60m, Draft: 16m) which are able to transit both the Malacca Strait and the Suez Canal, have emerged in 2013, aiming at lower shipping cost by economy of scale. At the same time, they inevitably increased port calls in a rotation to collect more cargo demand, resulting in the longer transit time than ever before. Taking this trend into account, the authors proposed the quick delivery scenario between East Asia and Northwest Europe by the NSR (Northern Sea Route)/SCR (Suez Canal Route)-combined shipping, of which 4,000 TEU ice-class containership transits the NSR during the summer season and the SCR in the wintertime, based on a year-round scheduled operation. The quick delivery scenario gives the shorter transit time at an affordable shipping cost depending on the NSR navigable season length. However, the quick delivery scenario cannot avoid uncertainties in navigation especially via the NSR in the summer season, due to rough weather, sea ice, low visibility and icing in the icy water section of the NSR. The authors preliminarily concluded that a year-round scheduled operation of the NSR/SCR-combined shipping will be secured, if the practical navigation schedule is appropriately prepared.     

A disaggregate analysis of factors influencing port selection

In this paper are presented the results of a multinomial logit model used to explain the selection of a port for each shipment exported from the US in December 1999. The model is estimated for combined shipments, and one model is estimated for each of four commodity types (bulk, foods, fabrics, manufactured). Results are compared across commodities to find the significance of the distance in either direction, the frequency of sailings, and the average size of vessels sailing along a route. Results of the estimation do not match those that would be expected. Potential reasons are given for such variations, along with numerous methods by which the modelling could be improved. Methods for improvement suggested include structuring of the model to represent more accurately the competitive scenario of each port, constraining the choice set for each shipments from characteristics of the carrier, and the commodity.     

无线网络自适应带宽预留的准入控制技术研究

未来无线网络不仅向用户提供非实时的数据业务同时也提供实时的诸如话音、视频等多媒体业务，这就要求无线网络必需向用户提供不同要求的服务质量保证。提出一种基于自适应带宽预留的呼叫准入控制方案，该方案不仅考虑了切换呼叫优先于新呼叫，还考虑到实时业务对非实时业务的优先级，并将实时业务的掉线概率控制在预定的门限值以下，有效地保证各类业务的服务质量。     

自动化集装箱码头水平运输设备的路径规划

为保证自动化集装箱码头能够实现水平运输设备的高效自动化作业,水平运输设备行驶路径的规划能力成为评价系统好坏的决定性因素。针对自动化集装箱码头水平运输系统如何生成最优行驶路径的问题,从码头布局、任务划分、车道选择及路径优化等多方面进行深入探究,提出一套自动导引车运行路径规划系统方案,明确路径规划需要考虑的因素,简化路径规划系统的计算逻辑,缩短自动导引车的运行距离,对提高水平运输效率具有重要意义。     

A disaggregate analysis of factors influencing port selection

In this paper are presented the results of a multinomial logit model used to explain the selection of a port for each shipment exported from the US in December 1999. The model is estimated for combined shipments, and one model is estimated for each of four commodity types (bulk, foods, fabrics, manufactured). Results are compared across commodities to find the significance of the distance in either direction, the frequency of sailings, and the average size of vessels sailing along a route. Results of the estimation do not match those that would be expected. Potential reasons are given for such variations, along with numerous methods by which the modelling could be improved. Methods for improvement suggested include structuring of the model to represent more accurately the competitive scenario of each port, constraining the choice set for each shipments from characteristics of the carrier, and the commodity.     

Ship-berth link performance evaluation: simulation and analytical approaches

In this paper we consider the performance evaluation of ship-berth link in port. The efficiency of operations and processes on the ship-berth link has been analysed through the basic operating parameters such as berth utilization, average number of ships in waiting line, average time that a ship spends in waiting line, average service time of a ship, average total time that a ship spends in port, average quay crane (QC) productivity and average number of QCs per ship. All the main performances of the ship-berth link are given. This is one of the problems faced by planners and terminal operators in ports. In this paper, we propose two models based on simulation and queuing theory, respectively, in order to determine the performance evaluation of ship-berth link in port. Numerical results and computational experiments are reported to evaluate the efficiency of the models for Pusan East Container Terminal (PECT).     

Ship-berth link performance evaluation: simulation and analytical approaches

In this paper we consider the performance evaluation of ship-berth link in port. The efficiency of operations and processes on the ship-berth link has been analysed through the basic operating parameters such as berth utilization, average number of ships in waiting line, average time that a ship spends in waiting line, average service time of a ship, average total time that a ship spends in port, average quay crane (QC) productivity and average number of QCs per ship. All the main performances of the ship-berth link are given. This is one of the problems faced by planners and terminal operators in ports. In this paper, we propose two models based on simulation and queuing theory, respectively, in order to determine the performance evaluation of ship-berth link in port. Numerical results and computational experiments are reported to evaluate the efficiency of the models for Pusan East Container Terminal (PECT).     

基于支持向量机的集装箱船航次配箱量的预测方法

集装箱船航次配箱量预测对集装箱码头管理和集装箱船配载具有重要意义。首先利用支持向量机(SVM)理论建立非线性回归模型,然后分析影响航次配箱量的因素,利用历史数据作为学习预测的样本,用训练好的回归模型对新的数据进行预测。实际计算结果表明:同BP神经网络预测模型相比,该预测模型具有良好的泛化能力及准确的预测结果。     

基于多智能体仿真的集装箱港口作业效率研究

集装箱港口生产作业系统是复杂的离散事件系统,数学建模方法难以构建针对整个系统的模型,而基于过程的仿真模型通常缺乏对设备调度的灵活性。为准确描述我国集装箱港口的作业流程,分析内卡配置数量对港口作业效率的影响,提出了基于事件驱动的集装箱港口多智能体(Multi-Agent)仿真模型。仿真结果表明:岸桥平均装卸效率(GCR)随着内卡数量的增加先急剧增加后缓慢增加,船舶平均等待时间(AWT)和平均在泊时间(AST)与岸桥平均装卸效率呈明显负相关关系。     

沿海集装箱港区港内锚地面积确定方法

设置港内锚地,是沿海集装箱港区缓解航道拥堵,提高港口服务水平的有效途径之一。为完善港内锚地面积确定方法的理论研究,基于计算机仿真技术,建立设置港内锚地的沿海集装箱港区船舶航行作业系统仿真模型,研究计算期内可能同时占用港内锚地的船舶数量及船型组合;计算不同锚泊方式下所需的港内锚地最大面积。仿真结果与分析结论为沿海集装箱港区港内锚地的规划建设及改造扩建提供参考。     

Designing optimal routes in a liner shipping problem

A real liner shipping problem of deciding optimal weekly routes for a given fleet of ships is considered and a solution method for solving the problem is proposed. First, all feasible routes for each ship are generated together with the cost and the duration for each route. The routes are given as input to an integer programming (IP) problem. By solving the IP problem, routes for each ship are selected such that total transportation costs are minimized and the demand at each port is satisfied. The total duration for the routes that are selected for a given ship must not exceed one week.

The real liner shipping problem is solved together with four randomly generated test problems. The computational results show that proposed solution method is suitable for designing optimal routes in several liner shipping problems.     

Designing optimal routes in a liner shipping problem

A real liner shipping problem of deciding optimal weekly routes for a given fleet of ships is considered and a solution method for solving the problem is proposed. First, all feasible routes for each ship are generated together with the cost and the duration for each route. The routes are given as input to an integer programming (IP) problem. By solving the IP problem, routes for each ship are selected such that total transportation costs are minimized and the demand at each port is satisfied. The total duration for the routes that are selected for a given ship must not exceed one week.

The real liner shipping problem is solved together with four randomly generated test problems. The computational results show that proposed solution method is suitable for designing optimal routes in several liner shipping problems.     

Studying port selection on liner routes: An approach from logistics perspective

The research aims to study the port selection in liner shipping. The central work is to set up a model to deal with port choice decisions. The model solves three matters: ports on a ship’s route; the order of selected ports and loading/unloading ports for each shipment. Its objective is to minimize total cost including ship cost, port tariff, inland transport cost and inventory cost. The model has been applied in real data, with cargo flows between the USA and Northern Europe. Afterwards, two sensitive analyses are considered. The first assesses the impact of a number of port calls on the total cost which relates closely to the viability of two service patterns: multi ports and hub & spoke. The second analyzes the efficiency of large vessels in the scope of a logistics network. The overriding result of this research is to indicate the influence of logistics factors in the decision of port choice. The research emphasizes the necessity to combine different factors when dealing with this topic, or else a result can be one-sided.     

航母机库飞机调运线路数字化设计方法初步研究

通过对栅格解耦法、设定节点法和线路段落划分法这三种方法进行分析，比较了其优缺点，得出航母机库内舰载机的调运线路可采用线路段落划分法。在结合图例的基础上，说明了机库内舰载机调运线路的设计以及线路的优化筛选，从而得出了几条最佳调运线路。同时，也提出了一些需进一步解决的问题：需研究用计算机处理技术来实现布列方案与线路段落划分法方案的智能化接口、采用数字化处理技术来实现调运线路全集表的制作并进行优化筛选。     

由订单看集装箱船发展趋势

介绍了当前世界集装箱船船队现状和订单情况,以及集装箱船大型化的发展历程.根据订单情况分析了目前集装箱船队的热门船型和特点,以及其成为主流船型的原因.同时,分析了在提高装箱系数、高速装卸、环保和低维护成本方面的集装箱船设计趋势.     

Assessing cruise port of call performance: a passenger-based approach using PLS modelling

In the present context of booming cruise demand, the study aims to advance the knowledge on port of call performance from cruise passengers’ perspective. The aim of this investigation was twofold: (1) to examine the structural links among port of call perceived quality–satisfaction–future intentions (revisit and word-of-mouth (WOM) behaviour); and (2) to test the moderating effect of cruisers’ motivation (push versus pull factors) to visit the port of call on the proposed structural links. Partial least squares path modelling was used to test the proposed model with a sample of 492 cruise passengers at a Mediterranean port of call. The findings revealed that port of call quality has a positive impact on port of call satisfaction, which in turn, strongly affects revisit and WOM intention. Besides, the results of the multi-group analysis indicated that the links between port of call quality–satisfaction and port of call satisfaction–WOM are moderated by cruisers’ motivation. Implications for port authorities and cruise lines are discussed.     

Fleet deployment optimization for liner shipping: an integer programming model

Extending and improving an earlier work of the second author, an Integer Programming (IP) model is developed to minimize the operating and lay-up costs for a fleet of liner ships operating on various routes. The IP model determines the optimal deployment of an existing fleet, given route, service, charter, and compatibility constraints. Two examples are worked with extensive actual data provided by Flota Mercante Grancolombiana (FMG). The optimal deployment is solved for their existing ship and service requirements and results and conclusions are given.