考虑商业信誉影响的海运集装箱超订模型

对于运输能力具有随机性的海运集装箱舱位超订问题,将运输能力假定为离散型的随机变量,考虑超订水平对商业信誉的影响,在具有空箱调运需求的情况下建立了以期望总成本最小化为目标的超订模型。基于混沌优化算法给出了求解最优超订水平的方法。当预订舱位的重箱出现比率为服从均匀分布的随机变量时,证明了超订模型最优解的存在性和唯一性。最后的算例表明了该方法的有效性。     

基于遗传算法的海运集装箱空箱调运成本优化

根据港口集装箱调运的特点,对空箱调运的问题进行分析,考虑租箱成本、运输成本、装卸成本和调运约束等条件,以最小化调运成本为目标,建立在保证重箱运输前提下的空箱调运的非线性整数模型.文中使用简单遗传算法和加入遗传算子的遗传算法分别对模型实例进行求解,实验表明,当采用加入遗传算子的遗传算法时获得的结果比采用简单遗传算法的更好.     

跨区域远洋航线空集装箱动态调运优化模型

由于海运业受世界经济不景气的影响,班轮企业竞争日益加剧。尽可能地降低营运成本是班轮企业生存和发展的关键因素。提出了跨区域远洋空集装箱动态调运优化模型（ECR-RDM）,该模型一方面针对传统模型（ECR-TM）基于港口间点到点空箱调运策略的缺陷,采用了基于港口集合到集合的空箱调运策略。另一方面,不同于传统模型解决空箱调运的静态分配特征,提出的模型可以根据实时需要动态分配空箱,一定程度上减少了由于调运计划和实际业务需求不同步性产生的各项成本。通过抽取实际业务中可能发生的六种情况,依次进行分析比较,验证了文中提出模型的有效性和可行性。同时,通过分析在可能的六种情况下租赁成本、存储成本、装卸成本在总调运成本中所占的比例,为班轮企业制定高效的运营策略提供决策依据。     

基于($D,U$)控制策略的港口群空箱存储与调运联合优化

针对区域港口群内陆公共腹地的空箱供需状况,构建多港口、多周期空箱存储与调运联合优化混合整数规划模型,利用马尔科夫决策过程与动态规划相结合的方法,在(D,U)库存控制策略下对港口群内各港口的空箱库存保有量区间进行动态优化,以此为基础对港口群公共腹地和各港口间的空箱调运方案进行优化,并以辽宁沿海港口群-----东北腹地为对象进行实证分析.实验结果表明,(D,U)控制策略下的空箱调运能够为船公司节省15.22%的总成本.选取公共腹地数量、公共腹地和港口空箱需求量、单位租箱成本以及单位库存成本进行灵敏度分析,进而验证(D,U)控制策略能够削弱船公司在外界环境发生变化时受到的影响.     

集装箱海运空箱分派随机规划模型研究*

通过对海运集装箱空箱分派过程的仔细分析,在考虑需求不确定性的基础上引入了空箱运输能力的不确定性这一重要因素,建立了同时考虑供需平衡约束以及需求和空箱运输能力不确定性的空箱分派随机规划模型,并应用机会约束规划方法对模型求解.最后通过数值仿真,揭示了运输成本、租箱成本和存储成本等参数和空箱运输能力的不确定性对集装箱空箱分派策略的影响机制.     

基于二阶段法的配煤调运系统的设计与实现

现有的配煤调运系统没有将车辆调度的优化问题和配煤优化问题作为一个整体考虑,存在较大的局限性,难以满足日益复杂的煤炭调运任务的需要。针对上述问题,提出了一种以经济效益最大化为目标的配煤调运数学模型,给出了基于二阶段法的该模型的求解算法,并以山西某矿业公司为例,设计了以该模型为基础的动态配煤调运系统。实际运行表明,该系统既降低了配煤调运的运输费用,又协调了用户需求与原煤质量指标之间的矛盾,具有广阔的应用前景。     

考虑心理代价的灾民疏散及救灾物资分派问题研究

在灾后灾民疏散和救灾物资调运过程中,灾民的心理恐慌影响到整个救灾行动的开展。考虑灾民在受灾点等待疏散以及在安置点内等待救灾物资的两种心理代价对救灾工作的影响,以救灾经济成本和灾民心理惩罚成本最小化为目标,建立一个灾民疏散及救灾物资调运的混合整数规划模型,确定灾后短期内的物资供应地、灾民疏散和救灾物资的调运计划,并用一个具体的算例验证所提出的模型。结果表明,救灾行动中应该充分考虑灾民的恐慌心理。     

多需求点、单货种军械调运模型算法研究

军械调运是军械保障工作中一个十分重要的环节,关系到军械保障工作能否快捷有效的完成。考虑到战时状况下军械调运的复杂性、快速性、危险性等特点,建立了多需求点、单货种军械紧急调运的优化模型,通过严格的数学逻辑推导,对模型给出了解析算法,并通过具体的算例表明了模型的正确性及算法的有效性。     

第四方物流调运优化系统的研究

本文结合实际的研究课题,在深入分析第四方物流的内涵的基础上,研究了国内某茧丝绸交易市场基于电子商务现代物流系统的构建,明确了第四方物流调运优化系统的运作优化思路,给出了并发移库调运优化模型,为更为通用的第四方决策优化模型的建立奠定了基础。     

真空箱强度的分析与优化

真空箱在工作时,由于要承受较大的压力,需要合理设计其壁厚.本文在分析原有的真空箱机械强度的基础上,使用有限元方法对真空箱进行优化设计,降低了产品的质量,并获得了最小壁厚尺寸,在实际应用中达到了满意的效果.     

基于区块链原理的集装箱共享模式下集装箱运输流程建模与仿真

针对集装箱存量共享与增量共享均不能有效实施的问题，提出基于区块链原理的集装箱共享模式。首先，阐述基于区块链原理的集装箱共享模式的运作机制；其次，分析在该模式的作用下，集装箱运输流程发生的变化；然后以Petri网理论为基础，使用CPN Tools分别建立传统模式与基于区块链集装箱共享模式下的集装箱运输流程的赋时着色Petri网（CPTN）模型；最后，对模型进行仿真实验，选取不同模式下接收订单到提取空箱装货的时间、路运段空车行驶时间比例、订单损失率、作漏装的集装箱比例这四项指标对比分析。实验结果显示，与传统模式下相比，基于区块链的集装箱共享模式下，发货人提箱时间缩短，集卡空车行驶比例减小5.28%，不再出现因船期与订单时间窗不匹配而损失的订单，作漏装的集装箱比例减小6.99%。通过仿真实验结果可知，基于区块链原理的集装箱共享模式不仅能够弥补集装箱存量共享与增量共享中存在的不足，而且对集装箱运输流程起到优化作用，是集装箱运输行业实现降本增效的一种有效途径。     

Application of a mixed fuzzy decision making and optimization programming model to the empty container allocation

Containerization transportation has been growing fast in the past few decades. International trades have been growing fast since the globalization of world economies intensified in the early 1990s. However, these international trades are typically imbalanced in terms of the numbers of import and export containers. As a result, the relocation of empty containers has become one of the important problems faced by liner shipping companies. In this paper, we consider the empty container allocation problem where we need to determine the optimal volume of empty containers at a port and to reposition empty containers between ports to meet exporters’ demand over time. We formulate this empty container allocation problem as a two-stage model: in stage one, we propose a fuzzy backorder quantity inventory decision making model for determining the optimal quantity of empty container at a port; whereas in stage two, an optimization mathematical programming network model is proposed for determining the optimal number of empty containers to be allocated between ports. The parameters such as the cost of loading container, cost of unloading container, leasing cost of empty container, cost of storing container, supplies, demands and ship capacities for empty containers are considered in this model. By taking advantages of the fuzzy decision making and the network structure, we show how a mixed fuzzy decision making and optimization programming model can be applied to solve the empty container allocation problem. The utilization of the proposed model is demonstrated with a case of trans-Pacific liner route in the real world. Six major container ports on the trans-Pacific route are considered in the case study, including the Port of Kaohsiung, the Port of Hong Kong, the Port of Keelung, the Port of Kobe, the Port of Yokohama and the Port of Los Angles. The results show that the proposed mixed fuzzy decision making and optimization programming model can be used to solve the empty container allocation problem well.     

Empty container repositioning strategy in intermodal transport with demand switching

In this paper, we study the empty container inventory repositioning problem with customer demand switching in intermodal transport. The objective of this article is to solve the empty container repositioning problem by contract coordination theory, and to improve the coordination of empty container management and the profit of each participant. We consider an intermodal transport system composed of the rail firm and the liner firm. First, we have considered the situation of no cooperation between the dry port and the seaport, and established a model where there is only the customer demand switching without the occurrence of empty container repositioning. Next, we consider the cooperation between the dry port and the seaport in the decentralized model and the centralized model, and set up the empty container repositioning models from the seaport to the dry port respectively. We analyse the optimal inventory level for the dry port and the seaport under different models, and the effect of the repositioning price on the optimal inventory level. We then apply the contract coordination theory to the empty container inventory repositioning problem. We propose an inventory coordination strategy based on a revenue sharing contract and coordinate the intermodal transport system by choosing the appropriate contract parameters. The results of the study show that under the guidance of the seaport, the revenue sharing contract can achieve a win-win situation for the dry port and the seaport.     

A recursive model for static empty container allocation

Backlogged empty containers have gradually turned into a serious burden to shipping networks. Empty container allocation has become an urgent settlement issue for the container shipping industry on a global scale. Therefore, this paper proposes an improved immune algorithm based recursive model for optimizing static empty container allocation which integrates with the global maritime container shipping network. This model minimizes the operating and capital costs during container shipping considering 0–1 mixed-integer programming. So an immune algorithm procedure based on a special twodimensional chromosome encoding is proposed. Finally, computational experiments are performed to optimize a 10-port static empty container shipping system. The results indicate that the proposed recursive model for static empty container allocation is effective in making an optimal strategy for empty container allocation.     

Optimization of empty container movements using street-turn: Application to Valencia hinterland

Empty maritime container logistics is one of the most relevant costs for shipping companies. In this paper two mathematical models (based on two different container movement patterns, i.e. with and without street-turns) were defined to optimize land empty container movements among shippers, consignees, terminals and depots, along with minimizing storage costs. One of the proposed optimization models was embedded in a simple Decision Support System (DSS) and then tested with real data, based on the operations in Valencia’s (Spain) hinterland. The results obtained confirm the benefits of implementing these kinds of models for the company, and additional experiments assess and quantify the advantage of using the more complex approach that is able to implement street-turn patterns.     

Effect of a redesigned two-wheeled container for refuse collecting on mechanical loading of low back and shoulders

The objective of this study was to compare the mechanical and perceived workload when working with a redesigned two-wheeled container and working with a standard two-wheeled container for refuse collecting. The three changes in the design of the container were a displacement of the position of the centre of mass in the direction of the axis of the wheels, a slight increase in the height of the handle and a slight increase in the horizontal distance between the handle and the wheel-axis, and an increase in the diameter of the wheels. The volume of the container remained 0.240 m3. Nine refuse collectors performed some of their most frequent daily activities with both types of containers in the laboratory. Kinematics and exerted hand forces were assessed as input for detailed 3D biomechanical models of the low back and shoulder to estimate net moments at the low back and shoulders, compressive forces at the low back and contact forces at the glenohumeral joint. Also, the refuse collectors rated the ease of handling the two-wheeled containers on a five point scale. The use of the redesigned container resulted in a decrease of the exerted hand forces of 27%, decreases in the net moments at the low back and shoulders of 8% and 20%, respectively, and a decrease of 32% of the contact force at the glenohumeral joint when compared to the standard container. However, pulling an empty redesigned container on to the pavement resulted in an increase of the shoulder moment of more than 100%. No differences between container types were found for the compressive forces at the low back. Pushing and pulling with the redesigned container was rated as easier than pushing and pulling with the standard container. No differences in subjective ratings were found for the tasks of turning the container or pulling an empty container onto the pavement. It is concluded that, provided that empty containers are placed back onto the pavement as infrequently as possible, the introduction of the redesigned container could result in a reduction of the low back and shoulder load for refuse collectors.