一种基于路段惩罚法的合理路径集生成算法

为了给路径选择模型提供合理的路径集输入,使路径集能够包含更多驾驶员实际选择的路径,提出了一种基于路段惩罚法的路径集生成算法.根据发生拥堵的频率定义路段的拥堵指数,然后根据拥堵指数确定新算法的惩罚规则:在上一次计算的最优路径中需要增加阻抗的路段,是拥堵指数较大路段,而不是原始算法提出的所有路段.通过定义合理的指标评价路径集生成算法的有效性,根据实测的驾驶员出行路径数据评价改进的路段惩罚算法、原始的路段惩罚法以及应用较广泛的随机分类组合法.结果表明,在几种算法中本文提出算法生成的路径与实测路径完全一致的比例最大.     

城市交通子系统期分初探——以成都市为例

城市交通运输系统是城市社会经济大系统的一个复杂子系统,是现代城市的动脉和各行各业的纽带。本文在城市交通系统特点的基础上,以成都市为例,利用空间层次结构进行子系统划分,并阐述各子系统功能、系统性和系统存在价值。     

Examining transport futures with scenario analysis and MCA

Climate change is a global problem and across the world the transport sector is finding it difficult to break projected increases in carbon dioxide (CO₂) emissions; there are very few contexts where deep reductions in transport CO₂ emissions are being made. A number of research studies are now examining the potential for future lower CO₂ emissions in the transport sector. This paper develops this work to consider some of the wider sustainability impacts (economic, social and local environmental) as well as the lower CO₂ transport impacts of different policy trajectories. Hence the central argument made is for an integrated approach to transport policy making over the longer term - incorporating scenario analysis and multi-criteria assessment (MCA) - to help assess likely progress against a range of objectives.The analysis is based on work carried out in Oxfordshire, UK. Different packages of measures are selected and two scenarios developed which satisfy lower CO₂ aspirations, one of which also provides wider positive sustainability impacts. A simulation model has been produced to help explore the strategic policy choices and tensions evident for decision-makers involved in local transport planning. The paper argues for a ‘strategic conversation’ (Van der Heijden, 1996) at the sub-regional and city level, based upon future scenario analysis and MCA, discussing the priorities for intervention. Such an approach will help us examine the scale of change and trade-offs required in moving towards sustainable transport futures.     

Quantifying the climate impact of emissions from land-based transport in Germany

Although climate change is a global problem, specific mitigation measures are frequently applied on regional or national scales only. This is the case in particular for measures to reduce the emissions of land-based transport, which is largely characterized by regional or national systems with independent infrastructure, organization, and regulation. The climate perturbations caused by regional transport emissions are small compared to those resulting from global emissions. Consequently, they can be smaller than the detection limits in global three-dimensional chemistry-climate model simulations, hampering the evaluation of the climate benefit of mitigation strategies. Hence, we developed a new approach to solve this problem. The approach is based on a combination of a detailed three-dimensional global chemistry-climate model system, aerosol-climate response functions, and a zero-dimensional climate response model. For demonstration purposes, the approach was applied to results from a transport and emission modeling suite, which was designed to quantify the present-day and possible future transport activities in Germany and the resulting emissions. The results show that, in a baseline scenario, German transport emissions result in an increase in global mean surface temperature of the order of 0.01 K during the 21st century. This effect is dominated by the CO₂ emissions, in contrast to the impact of global transport emissions, where non-CO₂ species make a larger relative contribution to transport-induced climate change than in the case of German emissions. Our new approach is ready for operational use to evaluate the climate benefit of mitigation strategies to reduce the impact of transport emissions.     

When human beings are like drunk robots: Driverless vehicles,ethics, and the future of transport

It is often argued that driverless vehicles will save lives. In this paper, we treat the ethical case for driverless vehicles seriously and show that it has radical implications for the future of transport. After briefly discussing the current state of driverless vehicle technology, we suggest that systems that rely upon human supervision are likely to be dangerous when used by ordinary people in real-world driving conditions and are unlikely to satisfy the desires of consumers. We then argue that the invention of fully autonomous vehicles that pose a lower risk to third parties than human drivers will establish a compelling case against the moral permissibility of manual driving. As long as driverless vehicles aren’t safer than human drivers, it will be unethical to sell them. Once they are safer than human drivers when it comes to risks to 3rd parties, then it should be illegal to drive them: at that point human drivers will be the moral equivalent of drunk robots. We also describe two plausible mechanisms whereby this ethical argument may generate political pressure to have it reflected in legislation. Freeing people from the necessity of driving, though, will transform the relationship people have with their cars, which will in turn open up new possibilities for the transport uses of the automobile. The ethical challenge posed by driverless vehicles for transport policy is therefore to ensure that the most socially and environmentally beneficial of these possibilities is realised. We highlight several key policy choices that will determine how likely it is that this challenge will be met.     

A bibliometric analysis on trends and characters of carbon emissions from transport sector

Transport sector’s substantial contribution to global greenhouse gas emissions has made it a growing area of study and concern. In order to identify trends and characteristics of carbon emissions research in the transportation sector we conducted a Bibexcel and complex network analysis for the period 1997–2016. In addition, we identify critical themes and contributions of research articles using h-index, PageRank and cluster analysis. We report contribution of countries, authors, institutions and journals, as well as performance of citations and keywords. Co-citing situations between different countries, authors, and institutions are also analyzed using network analysis. Between 1997 and 2016 we found a rise in publications on carbon emissions in the transportation sector and increased cooperation between countries, authors, and institutions. Authors from the USA, China and United Kingdom published the most articles and articles with the highest academic influence. Tsinghua University from China is the leading institution in carbon emissions research in the transportation sector. The most widely published author and cited author is Dr. He. We conclude our analysis by analyzing keywords and trends to suggest critical topic areas of future research. The systematic approach undertaken in this study can be extended and applied to other research topics and fields.     

加快哈尔滨铁路局保价运输发展的思考

开展铁路保价运输20年来,哈尔滨铁路局通过拓展保价业务、改进服务方式、用好保价资金等措施,在铁路保价运输增收创效、形象塑造、加快发展等方面实现新突破。     

铁路超重车安全通过简支梁桥的运输条件

以限制超重车通过的主要桥梁种类——铁路简支梁桥为例,以超重车通过桥梁时的运行活载系数必须小于桥梁的检定承载系数为基本条件,通过调整装载方案、优化车辆编组及限制车辆运行速度3种运输组织措施,降低超重车的运行活载系数,分析各种运输组织措施应满足的要求并推导相关的计算公式。提出铁路超重车安全通过简支梁桥的运输条件:在满足装载基本技术条件的前提下,合理选择车辆并尽量减少货物重心的偏移,以降低超重程度;当超重车的长度小于桥梁跨度时,应使用隔离车将超重车与超重车或机车隔离;隔离车应选用轴距大、轴重小的车辆,并在超重车前后加挂同等数量的隔离车;应限制车辆运行速度,而且超重车重心的横向偏移量和纵向偏移量必须满足相关要求;若调整装载方案、优化车辆编组和限制车辆运行速度等运输组织措施均不能保证超重车安全通过桥梁,则应采取加固桥梁等其他方法。     

光通信传输网排除故障技巧

光通信传输网是维护的重点,要求根据故障现象快速、准确判断故障点,缩短故障延时。为此,总结运行维护中排除故障的基本原则、分析思路、常用方法及典型实例等。     

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。