基于灰色预测模型的广东省货运总量预测研究

随着广东融入"一带一路"战略以来,广东货运总量呈现快速发展的态势,但同时货运总量增长过快导致物流基础设施承载负担过重的问题,因此对货运总量规模的测算和货运总量发展趋势的探讨显得尤为重要,利用2011-2017年广东货运总量及其构成等数据,运用EXCEL、MATLABR2018b和数学建模方法,建立灰色预测GM(1,1)模型并对模型进行验证,证明模型可用,然后分别对2018-2022年广东省货运总量及其构成进行预测.结果表明:1)广东省货运总量呈逐年增加趋势,在货运总量构成中,只有铁路货运量呈逐年衰减趋势.2)在五种运输方式中,货运量结构严重不均衡,公路货运量、水路货运量平均占比分别为72.554%、24.754%.铁路货运量、管道货运量和民航货运量三者平均占比之和仅占5.522%.这表明广东省运输方式和货运结构亟待优化,同时也反映政府在货运政策调适方面滞后.最后,从基础设施投入与货运网络体系优化方面提出相应的对策.     

构建地下物流系统网络

构建地下物流系统,缓解大城市拥堵已经成为了一个热点问题.主要内容包括:根据货物流量OD矩阵,以等比例方式计算了放入地下的货运收发总量为6.32万吨;综合考虑物流园区到需求点的距离和收发货运量因素,基于遗传模拟退火的聚类算法确定了4个一级节点及其服务范围,转运率分别为43%,57%,40%,66%.在每个区域,以服务半径和货运量为约束条件,共确定了24个二级节点;提出直连点和子点的概念,穷举各节点的连结方式,应用可行域的概念,在不影响转运率的前提下,调整二级节点的位置来优化轨道位置,计算得最优成本为206万元/天;提出建立中心节点的两种运输货物的方式以及网络连通度和网络容量等评价指标,分析了轨道的抗干扰能力;根据合理假设提出了网络建设顺序的优先原则,依据30年后整个地下网络的负载,给出了轨道可能的建设顺序.     

多货种多供需地海陆联运格局及对世界能源运输的预判

为优化国际货运规划方案,对可兼容配载的多种货物、多供需地、双港节点直达海运的海陆联运问题进行研究,由其运输关系结构研究其运输系统整体经济性组织的航线分布与货流路径模型.设定相关各量后,以营运期内所有供需地间陆运和海运总成本为目标,以供需能力、港口通过能力、船队收益及船舶停时等约束建立模型,并改进传统盈利航速的计算,模型可实现船舶航速和运输总成本的双重优化.以世界原油和致密油供需为例,划分各国主要产销地区和油港,应用模型结果显示出未来各贸易国间的基本经济航线及一定能力约束产生的航线分布、运力配置及物流路径,表明远距离航线的最优航速偏高,且海运段成本具有支配性影响.     

基于DEA-Malmquist模型的西北地区能源空间转运格局效率及其变化分析

西北地区有着丰富的能源资源,对其能源空间转运格局进行效率评价及全要素生产率时空演变分析,对推动整个地区的发展有着重要意义.运用DEA中的BCC模型,对2016年西北地区的铁路和公路货运效率进行研究.利用Malmquist指数方法及ArcGIS软件,进一步分析2010-2016年西北地区铁路、公路货运全要素生产率的时空演变和地区差异.研究表明:1)2016年西北地区铁路货运效率总体水平较高,公路中等;存在地区差异性,东部整体高于西部;规模效率决定其有效性.2) 2010-2016年铁路和公路的Malmquist指数整体较稳定,技术进步变化对该指数影响最大.从时空演变来看,2010-2016西北地区铁路货运的Malmquist指数先升后降,地区差异先减小后增大;公路货运的Malmquist指数先降后升,地区差异先减小后增大最后又减小.     

利益相关者视角下公路货运超限超载的对策研究——基于演化博弈模型和仿真分析

为有效遏制公路货运超限超载现象,深化交通执法领域的“放管服”改革,本研究针对运输者、稽查人员和交管部门等利益相关者,建立三方演化博弈模型,研究超限超载运输中各利益主体的决策演化过程,并对稳定策略的演化路径进行仿真分析,比较不同参数组合下不同政策力度的治理效果。研究发现,提高超限超载运输的处罚系数可以明显规范运输者的行为;管理成本越低,监管部门的策略越可能向积极监管的方向演化;三方博弈系统存在两种可能的演化稳定策略,加重对稽查人员消极执法行为的处罚、加大资金设备投入能够提高系统向最优状态演化的概率。     

中心城市货运市场建设项目的系统评价研究

本文通过对公路货运市场的生产和经营状况、所处的经营环境以及货运市场中的运力和货运需求进行了分析 ,提出了货运市场建设项目的评价指标体系 ,并且利用系统评价模型进行评价 ,得出了满意的结果     

基于综合效益的城市地下物流网络设计与优化方法

针对城市地下物流系统(Underground Logistics System,ULS)的特征,对一系列ULS网络节点选址与优化问题进行了建模分析.1)从解决城市交通拥堵的角度出发,探讨了物流地上地下分配的三种方案,并建立了地下货运OD评价模型.2)综合权衡货运量与货源距离,基于改进的模糊C均值聚类确定ULS—级节点的选址和辐射范围.3)对每个一级区域构建了ULS二级节点选址优化模型,通过人工免疫算法搜索最少覆盖节点群及节点的最优归属.4)建立多目标ULS网络规划模型,结合Prim算法与Dijkstra算法实现货物地下运输路径的最优选择,并采用栅格覆盖的思路在节点服务范围内对ULS网络进行费用优化.5)提出ULS网络效能评估指标,设置中心节点以提高系统运输效率和抗风险能力.     

基于DEA的海关通关综合效率研究

海关在进出口过程中扮演着"国门"的重要角色,其通关效率会影响贸易进程.目前学者们在评价海关通关效率时还局限在货物在少数几种运输方式下进口或出口的通关效率,综合的评价较为稀缺.海关可以看作是一个多投入多产出的系统,这符合DEA方法的特征.同时,货物运输方式影响通关效率,这是海关通关的一个特征.研究使用DEA-综合评价方法对19个总署直属海关在进口与出口及不同运输方式下的货物通关效率进行评估,有助于提出持续提高通关效率的对策建议.     

广义D运输问题

D运输问题是一类要求将货物在某一个时间以前如数运抵目的地的运输问题,比如节日物资的运输问题.基于物流管理的需要,提出了广义D运输问题.广义D运输问题是各个销地对货物的运抵时间有不同要求,即各个销地对于货物的需求时间不一定相同的一般情况.建立了广义D运输问题的数学模型,引入了可实施解、满意解、最优解等概念,给出了求解方法和一个计算例子.     

“冰上丝绸之路”货物吸引的中国沿海港口空间分异及类型识别

通过构建港口货物吸引潜力模型,预测“冰上丝绸之路”建设完成后,中国沿海港口体系针对中国-西北欧海运贸易的货运空间格局并识别货运空间类型。结果显示:在空间格局方面,吸引潜力分布呈由北向南逐次递减趋势;液化天然气、煤炭、铁矿石、木材和潜力总值具有显著的空间正相关性,石油和集装箱在空间上表现为随机分布模式;环渤海和长三角已具有一定的港口层级结构特征,东南沿海、珠三角和西南沿海低值集聚特征较明显。在货运空间类型方面,港口体系结构的重心在北部港口地区,环渤海大型港口的综合性货流聚集能力要强于其他地区,沿海港口基本符合货运规模越大,其综合货运等级越高的趋势。     

考虑运营稳定性的内支线班轮航线网络规划模型

货主选择承运航线的影响因素,既包括挂靠港口的计划到港时间与单箱运价,还包括反映班轮运营稳定性的甩箱率与准班率。对此,文章将挂靠港口的航行与在港时间不确定引入研究,并对挂靠港口间的不确定性建立联系,基于航次仿真来计算各挂靠港的到港时间分布、船舶的航次最大载箱量分布。以班轮航线的甩箱率与准班率限制、内支线最大船型与最长往返时间为约束,在优化内支线航线网络结构的同时,计算航线适配船型、班期密度及挂靠港计划到港时间。针对所构建的带不确定参数的NP难问题,文章设计了基于模拟仿真的智能优化算法,通过方案仿真技术来处理输入模型的众分布函数,借助智能优化原理从大范围解空间内寻找满意方案。文末对船舶航次仿真与网络规划模型的有效性进行了验证,算例分析表明:内支线班轮航线网络的货主选择比例达64%,且不论货主更偏好运输时间或价格,航线方案皆能贴近货主偏好。     

Synchronizing vans and cargo bikes in a city distribution network

One of the significant side-effects of growing urbanization is the constantly increasing amount of freight transportation in cities. This is mainly performed by conventional vans and trucks and causes a variety of problems such as road congestion, noise nuisance and pollution. Yet delivering goods to residents is a necessity. Sustainable concepts of city distribution networks are one way of mitigating difficulties of freight services. In this paper we develop a two-echelon city distribution scheme with temporal and spatial synchronization between cargo bikes and vans. The resulting heuristic is based on a greedy randomized adaptive search procedure with path relinking. In our computational experiments we use artificial data as well as real-world data of the city of Vienna. Furthermore we compare three distribution policies. The results show the costs caused by temporal synchronization and can give companies decision-support in planning a sustainable city distribution concept.

     

Horizontal cooperation among freight carriers: request allocation and profit sharing

In modern transportation systems, the potential for further decreasing the costs of fulfilling customer requests is severely limited while market competition is constantly reducing revenues. However, increased competitiveness through cost reductions can be achieved if freight carriers cooperate in order to balance their request portfolios. Participation in such coalitions can benefit the entire coalition, as well as each participant individually, thus reinforcing the market position of the partners. The work presented in this paper uniquely combines features of routing and scheduling problems and of cooperative game theory. In the first part, the profit margins resulting from horizontal cooperation among freight carriers are analysed. It is assumed that the structure of customer requests corresponds to that of a pickup and delivery problem with time windows for each freight carrier. In the second part, the possibilities of sharing these profit margins fairly among the partners are discussed. The Shapley value can be used to determine a fair allocation. Numerical results for real-life and artificial instances are presented.     

A review of recent research on green road freight transportation

Road freight transportation is a major contributor to carbon dioxide equivalent emissions. Reducing these emissions in transportation route planning requires an understanding of vehicle emission models and their inclusion into the existing optimization methods. This paper provides a review of recent research on green road freight transportation.     

Improving LTL truck load utilization on line

In this document we consider an optimization problem which origins from freight exchanges. The aim is to increase the utilization of already scheduled road transportation activities by accepting extra loads. Such utilization increase reduces costs for the freight sender, increases revenue for the transportation provider, and reduces congestion and pollution for the society at large.     

压力、补偿机制与知识分享:基于演化博弈的分析

以往对于知识分享影响因素的研究并不少见,但从员工所面临的来自组织环境的多重压力出发,采用演化博弈理论进行分析的研究仍是空白。本文引入时间压力、同辈压力和补偿机制,构建组织内员工知识分享的演化博弈动态模型,通过求解复制动态方程得到演化博弈的稳定均衡解,再进行数值模拟。研究结果表明,时间压力和同辈压力是知识分享的重要影响因素。其中,时间压力通过影响分享者的时间成本而对知识分享产生负向影响,同辈压力通过让分享者获得同辈群体的认可而对知识分享产生正向影响;补偿机制能够有效地促进知识分享行为的发生。此外,系统的初始状态对系统的演化结果也具有显著影响。最后,针对组织实际提出管理建议。     

Cargo ships routing and scheduling: Survey of models and problems

When a ship costs thousands of dollars per day, significant savings can be achieved by proper fleet routing and scheduling. In contrast to vehicle scheduling, relatively little work has been done in ship routing and scheduling. This paper discusses briefly the differences between vehicle and ship routing and scheduling and the reasons for the low attention to ship scheduling in the past. The various modes of operation of cargo ships are described and a classification scheme for ship routing and scheduling models and problems is proposed. A review of ship routing, scheduling and related models is provided. The review is broken down into the following categories: transportation system models, liner operations, tramp shipping, industrial operations and other models. Finally, recent trends in ship scheduling, shortcomings in existing models and requirements from realistic models are discussed.     

基于灰色预测模型的广州港货运发展研究

新冠肺炎疫情对广州港的货运发展产生了一定程度的影响,但目前仍然缺少相关的定量研究.基于灰色预测模型,利用港口货物吞吐量、外贸货物吞吐量、集装箱吞吐量三个货运指标,在新冠肺炎疫情没发生的这一假设下,推测2020年1-8月广州港的各货运发展指标值.基于预测值与实际值的比较,定量研究广州港的货运发展受新冠肺炎的影响值,反映新...     

Combined Sea and Land Transportation

An important problem today in the field of transportation is the standardization of the cargo, e.g. by using containers, and the design of the handling and transportation equipment for the specific cargo to be transported.The paper presents a method for determining the transportation system with emphasis on sea transport. Thus the cargo is to be transported by sea from the factory to customers spread over a large region, e.g. Europe. The problem is to select the ports of call, the quantities to be delivered at the ports, as well as the size and type of vessel.This problem resembles the warehouse location problem (the location of ports) but requires in addition the determination of ship size, type of ship and whether one or more ports should be called at on each journey with a single ship. A discussion is also presented as to the possibility of considering randomness in the system with respect to customer demand and weather conditions.The method used resembles that suggested by Baumol and Wolfe for the ware-house location problem. A concave function of the quantities delivered at each port is derived and this is then shown to converge to a local optimum.An example is solved to illustrate the method.