Transportation agencies experiences with decision support systems for airport ground access planning

This article reports on a field investigation into the ways that transportation agencies use quantitative and qualitative information for making strategic decisions regarding airport ground access. The study analyzes the value of this information for planning airport ground access improvements at seven major international airport sites.The major finding of the research is that quantitative modeling for strategic decision support is very difficult, costly and time consuming. Modelers are confident that the models are accurate and reliable but executives generally lack confidence in the results. Transportation officials believe that the information supplied is flawed by a number of defects that minimize its value for strategic decision makers. The information defects described in this article provide an analysis of the structural difficulty of using quantitative modeling for transportation problems of strategic importance. To date, qualitative information is not frequently used, but some transportation agencies are considering its application to designing transportation services. Although this study is limited to airport ground access, the authors feel that this evidence, in conjunction with the evidence from other studies in the transportation area, dictates a need for wariness in the development of decision support systems for transportation planners. Developers of decision support systems for transportation planners must be aware of modeling costs and defects and consider how to improve the timeliness, relevance and credibility of information quantitative models provide transportation executives. Fundamentally it is important to recognize that decision makers tend, either singularly or in concert with other individuals or groups, to be the champions of a long-term vision for the community. When modeling produces inconsistent or wide ranging results that contradict their position, decision makers may not only discard modeling activities, but lose confidence in the models altogether. As a consequence, transportation planners are faced with the challenge of how to improve quantitative modeling. The most reliable and effective means for improvement is incorporation of qualitative techniques which provide greater understanding of customer perceptions and human behavior.     

Trip Chain's Activity Type Recognition Based on Support Vector Machine

This paper focuses on support vector machine (SVM) based trip chain's activity type recognition. First, the time-series location information of person trip is processed to obtain the trip chain elements including moving processes and activities, and the activity options are extracted from the geographic information system (GIS) around the activity sites. Second, the activity features are drawn from spatio-temporal factors of trip chain to serve as the input feature vector of classifier. A SVM based one-to-one classifier is established and the method of one-to-one classifier voting is adopted to decide the most likely activity type from the activity options. Finally, the classifiers are trained with simulation data based on the Gaussian radial basis (RBF) kernel function and the multilayer perception (MLP) kernel function respectively, and then examined by cross validation. The result shows that in the one-to-one classifying scheme, the highest and lowest right recognition rate with RBF are 99% and 62%, and the corresponding results with MLP are 97% and 54%, respectively.     

“交通引导发展”的轨道线交通衔接对策思考

轨道交通为城市的空间拓展起到战略引导作用,其沿线用地发展直接影响到城市格局态势和功能发挥.交通衔接效果的好坏是决定轨道交通服务能力的主要方面.通过研究城市空间拓展的规划理念与方向,思考"交通引导发展"的轨道线的交通衔接对策,并以广州地铁3、4号线为例进行详细探讨.     

城市轨道交通列车自动监控系统的研究

介绍城市轨道交通ATS系统的结构、功能和接口。通过对系统关键技术的研究和当前城市轨道交通整体局势的分析，提出了该系统具有良好的使用价值和推广价值，及广泛的应用前景。     

城市轨道交通车辆最高运行速度的选择

研究目的:通过对影响列车最高运行速度的几大要素进行分析,寻找轨道交通车辆选型时确定列车最高运行速度等级的一般规律,从而达到节约能源、减少车底数的目的.研究结论:确定城市轨道交通车辆最高运行速度等级时一般以平均车站间距作为首要依据,车站间距约为3.4 km时,推荐选择列车最高运行速度120 km/h;当车站站间距约为2.3 km时,推荐选择列车最高运行速度100 km/h;当车站站间距约为1.5 km时,推荐选择列车最高运行速度80 km/h.     

城市轨道交通新线设备国产化评审及进口设备免税申报管理

由于新建城市轨道交通的企业对新线设备国产化管理经验的不足,难以在较短时间内组织好新线设备国产化申报及进口设备免税申报工作。介绍了相关政策背景并分析申报管理的重难点,提出明确企业部门责职、规范流程的建议。通过明晰申报流程,理顺各种工作界面间的关系,帮助企业获得相关进口设备免税,以及顺利通过设备国产化审核。     

参数化绘制城市工程管线综合图

介绍了城市工程管线综合图参数化绘图技术.该绘图技术有效地解决了城市工程管线综合图的绘图问题.参数化绘制城市工程管线综合程序可直接安装在AutoCAD软件中,并配有可视化交互界面,使设计人员方便、快捷完成城市工程管线综合图的设计绘图工作.     

城市轨道交通无人驾驶信号系统设计需求分析

城市轨道交通无人驾驶系统是一种代替司机行使列车控制和驾驶功能的信号系统。分析了无人驾驶技术在成本和节能方面的优势,就无人驾驶系统对车载子系统、轨旁子系统、停车场、日常运营服务的设计需求进行了分析。从设计层面看,CBTC(基于通信的列车控制)系统是最接近无人驾驶系统的信号系统,以CBTC系统为基础设计的无人驾驶系统或直接由CBTC改造升级为无人驾驶系统的方案是最为合理也最经济的选择。     

高速铁路钢轨电力牵引回流集中监测探讨

通过对当前中国高速铁路电力牵引供电方式的介绍,引申出集中监测和分析高速铁路钢轨电力牵引回流的重要意义,提出了高速铁路钢轨电力牵引回流集中监测的方法,为保障高铁运营安全提供了重要的安全保障手段。     

基于NI CompactDAQ的轨道状态分布式在线监测系统

针对日益增加的城市轨道交通线路钢轨安全和减振降噪方面的需求,介绍一种基于NI Compact DAQ的轨道状态分布式在线监测系统。阐述了系统的基本组成、功能和软硬件总体设计。系统采用以NI Compact DAQ为核心的机箱,通过对关键路段不同站点间的振动、噪声、脱轨系数、钢轨动态位移、轨道结构沉降等动态参数进行实时在线监测,为实时掌握轨道动态参数建立一个开放式的监测平台。