空车配货VRP问题的路径匹配算法

针对现有VRP（Vehicle routing problem）问题的精确解法和启发式算法应用于空车配货信息检索时的局限,引入图的概念,提出了一个基于交通路网的路径匹配算法,给出了算法复杂度分析。该算法利用交通路网中各结点之间的距离关系,检索给定起讫点间及起讫点与各自邻近结点群之间存在的配货信息,同时规划出收益费用比最优的行驶路径,并能根据配货行驶路径的特点对检索出的所信息进行分析、评价和优选,以方便空车配货组织。最后用一个仿真实例验证算法的有效性。     

Freight Demand Management and the Potential of Receiver-Led Consolidation programs

The paper defines the field of Freight Demand Management (FDM), and positions it as an important component of transportation policy and management. To establish the rationale for FDM, the paper studies the effects of the agent interactions at the core of supply chains, and identifies the important role played by the receivers of supplies in determining when and how deliveries are made. The paper classifies the various modalities of FDM, and summarizes the real-life experiences of their implementation. To illustrate the potential of FDM, the paper analyzes Receiver-Led Consolidation (RLC) programs. The paper provides background on consolidation programs, and estimates a behavioral model to shed light on the factors explaining receivers’ interest in cargo consolidation. The resulting model is used to estimate expected participation in a RLC program in New York City. These results are complemented with freight-trip generation analyses, and a behavioral micro-simulation to estimate potential reductions in freight traffic and vehicle-miles-traveled. The results show that RLC programs could bring significant benefits to large metropolitan areas, reducing freight vehicle-miles-traveled and congestion levels.     

Impacts of information technology and urbanization on less-than-truckload freight flows in China: An analysis considering spatial effects

Understanding the relationship between socioeconomic factors and the Less-than-Truckload (LTL) freight flows is important for transportation planners and policy makers. This paper explores the impacts of information technology, urbanization on LTL freight flows by using a spatial autocorrelation model with freight flow data from a leading LTL company in China. The results show that all IT variables and urbanization variables have positive effects on freight flows. Distance, as expected, is negatively correlated with the freight flow volume. The application of the spatial autocorrelation model further shows that origin dependence, destination dependence and OD dependence are all significant, justifying the consideration of spatial interdependence. Finally, policy implications are discussed based on the estimated results. These findings shed light on the impacts of internet and urbanization on freight transportation, and contribute to the design of freight policies and the development of the LTL industry.     

航运市场运费套期保值方法探讨

分析研究了2种运费套期保值方法远期运价协议和运价指数期货合约，通过典型案例论证了租船人和船东都能利用这2种方法，锁定运费收入或支出，从而规避运价风险的目的；同时对这2种方法进行了分析比较，指出运价指数期货合约具有灵活性且安全的特点，但二者费用有差异，运价指数期货合约需要一定的保证金，实际费用等于经纪人的佣金(通常为0．3％)加上现金保证金的利息。     

铁路货车通过曲线轨道时的非线性运动稳定性研究

根据直线轨道上非线性车辆系统蛇形运动的极限环和曲线轨道上车辆的动态特性,给出曲线轨道非线性车辆系统蛇形运动的极限环,并计算出货车的非线性临界速度,分析曲线半径和外轨超高对货车非线性临界速度的影响。结果表明:在大锥度、横向位移激扰、轮对冲角等因素的作用下,货车轮对在曲线轨道上易出现蛇形失稳,并且在蛇形失稳时轮对的横向振荡剧烈,蛇形波长为3.6 m;与直线轨道上的极限环不同,曲线轨道上非线性车辆系统相对轨道中心线而言,具有2个稳定的极限环;当重载货车空车通过半径600 m、超高55 mm曲线轨道时,其非线性临界速度为76.4 km.h-1,低于直线轨道上的临界速度,说明曲线轨道的半径和外轨超高对车辆非线性临界速度有明显的影响,而且半径和超高越大,临界速度也越高,但当半径和超高增加到一定程度,临界速度不再随之增长。     

货车装载工况对车辆通过小半径曲线时的垂向平稳性影响

将货物、车体和摇枕作为1个系统,基于弹簧悬挂装置垂向受力的变化,提出货车垂向平稳性评价指标。运用建立的货车在曲线上运行时的垂向平稳性模型,以C64k敞车为例,研究4种典型装载工况下重车重心高、货物重心横向和纵向偏移量与货车通过小半径曲线时垂向平稳性的关系。研究表明:用作用在每个弹簧悬挂装置的垂向载荷变化判定货车运行的垂向平稳性,可更直观描述货车装载工况对车辆垂向平稳性的影响;对货车的垂向平稳性影响以货物重心的纵向偏移量最大,而重车重心高度的影响最小;计算结果为确定合理的重车重心高度以及货物重心横、纵向偏移量的限制值提供了科学依据。     

货车交叉杆组成疲劳试验台研制

按照TB/T 3225—2010《铁道货车交叉杆组成》要求,选择液压伺服作动器实现交叉杆组成的水平载荷加载和垂直方向扭转位移施加,从水平运动机构和扭转运动机构2方面出发,研制交叉杆组成疲劳试验台。试验台经转K2/K6型和转8G/转8GA转向架用交叉杆组成验证,功能满足标准要求,且使用方便,节约成本。     

铁路货车配件产品i认证过程中有关检验问题的探讨

介绍铁路货车配件产品认证现状及其涉及的入厂检验、现场见证检验、型式检验、出厂检验和常规检验。结合已经开展的51种货车配件的产品认证工作,就生产企业检验的执行与检验文件规定的一致性、认证机构对检验项目的选择等方面展开探讨,并提出建议。     

电子商务环境下提升货运事故理赔服务质量的思考

针对现行货运事故理赔服务中存在的问题,通过既有货运事故理赔业务流程的优化调整,在电子商务环境下研发一套基于互联网的货运事故理赔服务系统与货运电子商务平台对接,从而提升货运事故理赔服务质量。在阐述货运事故理赔服务系统实施步骤的基础上,提出进一步完善电子商务环境下货运事故理赔服务的措施。     

铁路货运发展模式与策略研究

运用SWOT分析法,针对我国铁路货运发展现状,对铁路货运融入物流系统的优势、劣势、机会、威胁进行系统分析,提出面向物流系统的铁路货运发展模式;根据我国铁路货运融入现代物流的发展过程,提出优势—机会发展战略、优势—威胁发展战略、劣势—机会发展战略和劣势—威胁发展战略的具体措施。