基于UBGPM-Markov的铁路货运量预测方法

针对铁路货运量发展变化的非线性特性,采用非线性灰色模型中的无偏GM（1,1）幂模型进行预测,并用状态划分更为精细后的马尔可夫链修正预测值,从而建立优化后的UBGPM-Markov模型.通过对我国2000~2012年铁路货运量实例分析,与改进GM（1,1）模型、无偏GM（1,1）模型2种预测方法进行了比较,比较显示无偏GM（1,1）幂模型具有较高的预测精度.优化后的UBGPM-Markov模型更是显著提高了预测精度,将平均绝对百分误差（MAPE）由2.11%减少到0.55%.     

货运枢纽适度远离中心城区布局研究

在采集大量数据的基础上,对不同类型的城市进行分类,统计分析了国内外主要铁路和公路货运枢纽距离中心城区的距离,发现了货运枢纽在不同类别城市中的分布规律,并总结出货运枢纽要适度远离中心城区布局,为铁路和公路货运枢纽的发展规划提供了实例数据参考,具有重要的意义。     

空重车流不均衡条件下拉萨西货物运输组织优化探析

随着拉萨西站货运业务的开展,进出藏货物不均衡的状况日益突出.为了缓解大量排空车数给运输组织带来的影响,需要结合高原铁路货物运输组织的特点,整合出藏货流、优化拉萨西货运站工作组织.     

铁路货车脱轨事故风险评价研究

综合应用安全系统工程的方法论,提出现阶段铁路货车安全评价的方法,在此基础上对影响货车脱轨的因素进行了全面细致的分析归类,应用层次分析法及模糊综合评价法建立了货车脱轨定量评价模型,并进行了实例分析。     

基于灰色Verhulst模型的民航远期货运量预测研究

从分析民航远期货运量预测的难点入手,引入灰色Verhulst模型,并分析了此理论应用于中国民航长期货运量预测的可行性及方法,在此基础上建立了民航货运量的Verhulst预测模型,结合中国民航货运量的历史数据进行了研究和分析。研究表明,灰色Verhulst模型在民航长期货运量预测方面具有较好的应用效果。     

基于TOPSIS的公路货运枢纽布局优化分析

公路货运枢纽布局影响因素众多,其合理的布局和规划可以更好地发挥综合运输的总体效益,促进社会发展。利用TOPSIS（逼近理想解排序法）法对原始数据的信息充分利用,其结果能精确的反映各评价方案间的差距特点,对货运枢纽布局优化问题进行研究,得出良好的可比性评价指标排序结果,使得公路货运枢纽布局优化结果更加科学、合理。     

Calculation of external costs for freight transport

Abstract

The negative impacts of transport are in general associated with costs. These costs are usually denoted as ‘external costs’ or ‘externalities’. This paper presents a tool for calculating external costs for freight transport together with its application to a number of case studies. The categories considered include: air pollution, greenhouse gases, noise, accidents and congestion. Results are presented for a number of different transport alternatives as total costs and divided into categories. The uncertainties in the results are discussed. The assessment of these costs is essential for predicting future transport costs.     

Estimating Freight Transport Price Elasticity in Multi-mode Studies: A Review and Additional Results from a Multimodal Network Model

Abstract

The paper presents a detailed comparative review of price/cost elasticity estimates published in a number of studies on multi-mode freight transport demands. It attempts to determine which factors could explain the wide diversity of estimates: data aggregation, diversity of markets, and methodology. It also presents new estimates for rail, road, and waterway modes, derived from a multimodal freight network model of the Rhine area market. Direct and cross-elasticities are estimated for 11 groups of commodities and per distance category. The results are critically assessed by comparison with the reviewed studies. The paper concludes with a few recommendations about meaningful uses of existing estimates and the need for additional experiments with different methodologies applied on a common data basis.     

A behavioral analysis of freight mode choice decisions

This paper develops a behavioral analysis of freight mode choice decisions that could provide a basis for an acceptable analytical tool for policy assessment. The paper specifically examines the way that truck and rail compete for commodity movement in the US. Two binary mode choice models are introduced in which some shipment-specific variables (e.g. distance, weight and value) and mode-specific variables (e.g. haul time and cost) are found to be determinants. The specifications of the non-selected choice are imputed in a machine learning module. Shipping cost is found to be a central factor for rail shipments, while road shipments are found to be more sensitive to haul time. Sensitivity of mode choice decisions is further analyzed under different fuel price fluctuation scenarios. A low level of mode choice sensitivity is found with respect to fuel price, such that even a 50% increase in fuel cost does not cause a significant modal shift between truck and rail.     

基于实测数据的地铁列车能耗特征分析

基于车载装置实时采集的北京地铁6、8、13号线列车牵引能耗、辅助能耗及再生能等分项 能耗和牵引变电所电表记录的统计能耗,探析了地铁牵引系统能耗构成及影响因素特征。得到 如下结论：列车运行能耗中38%~60%用于克服阻力和电机效率损失,9%~20%用于辅助设备,再 生能占比约20%~49%。影响车公里牵引单耗的因素包括站间距、纵断面、列车性能、技术速度及 满载率等。随站间距减小,牵引单耗呈幂级增长;纵断面设计为“高站位、低区间”的节能坡形式 有利于减少单耗;质量轻、阻力小、电机效率的列车更节能,不同车型能耗差异可达10%;技术速 度增加引起牵引单耗增长,平峰时段可适当降低技术速度。满载率每降低10%,可减少牵引单耗 2%。影响再生能的因素主要包括站间距与制动初速度,站间距越小则再生能产生量越多,但摩擦 制动产生的动能损失也越大,总体不利于车公里单耗的降低。影响辅助能耗的主要包括气温与 客流,辅助能耗随气温或客流增长而增高,地下线辅助能耗随气温增长变化幅度较地上线更小。