Distribution models for start-up lost time and effective departure flow rate

Due to its importance, lots of investigations had been carried out in the last four decades to study the relationship between phase duration and vehicle departure amount. In this paper, we aim to build appropriate distribution models for start-up lost time and effective departure flow rate, by considering their relations with the frequently mentioned departure headway distributions. The motivation behind is that distribution models could provide richer information than the conventional mean value models and thus better serve the need of traffic simulation and signal timing planning. To reach this goal, we first check empirical data collected in Beijing, China. Tests show that the departure headways at each position in a discharging queue are very weakly dependent or almost independent. Based on this new finding, two distribution models are proposed for start-up lost time and effective flow rate, respectively. We also examine the dependences of departure headways that are generated by three popular traffic simulation software: VISSIM, PARAMICS and TransModeler. Results suggest that in VISSIM, the departure headways at different positions are almost deterministically dependent and may not be in accordance with empirical observations. Finally, we discuss how the dependence of departure headways may influence traffic simulation and signal timing planning.     

繁忙铁路干线调度集中调试开通方案的研究

调度集中系统是铁路运输调度集中指挥的重要行车设备，是提高铁路调度指挥效率、保证行车安全的重要系统。以胶济线为背景，详细分析胶济线分散自律调度集中的工程施工、系统调试方案及调度集中系统开通方案，为全路繁忙铁路干线调度集中工程的实施、开通提供参考。     

虚拟和谐交通系统Agent仿真

本文在虚拟世界里,构造了交通系统的和谐仿真。首先介绍了智能体Agent、多智能体组成的系统MAS及其规则,然后分析交通环境(道路)、车辆、人组成的系统,利用集对分析(SPA)、人、事、物系统(WSR)和集对匹配系统(SPM)以及A.Kaufmann最强路算法与集对匹配合成算法,构造出和谐的道路、车辆、人、环境, 并给出智能调度的应用实例。     

铁路客技站车底作业排序模型与算法

作为铁路客技站核心工作之一的车底作业安排包括车底出入库安排、车底停留线运用和调机运用3方面的内容,是CTC（调度集中系统）条件下客技站分散自律控制的基本组成部分。以车底、调机运用、车底停留线为研究对象,利用排序理论,以总晚点数最小为第一目标和调机均衡运用为第二目标建立具有柔性流水作业性质的车底取送模型,以客技站股道均衡运用为目标函数构造车底停留线运用模型。运用排序思想和两阶段法,并结合松弛算法提出了车底作业计划表的原始算法以及基于4种解改进优化策略的调整优化算法。实例表明,提出的模型及算法能够快速、合理地确定车底的出入库作业安排、车底停留线运用方案以及相应的调机运用方案,并能充分运用车站的各项资源。     

热带气旋生成的预报现状与船舶实用监测信息

介绍了目前对热带气旋发生及发展研究的最新理论及预报业务,指出目前热带气旋发生、发展的预报水平与实际需求仍有很大距离。推荐了美国为弥补热带气旋的发生、发展预报的不足而采取的对热带气旋的胚胎——热带扰动和热带低压进行监测的编号情况和方法。同时,根据几年来对上述情况的跟踪和分析,提供了几个较为实用的,可以及时了解全球热带扰动和热带低压最新发展动态的网站。所提供的理论动态和信息,可使船舶驾驶员和船舶安全管理人员了解目前国内外热带气旋发生、发展的研究和预报现状,在日常工作中及时了解热带气旋初生和发展的动态,最大程度地降低新生热带气旋对在热带气旋活动海区航行船舶的威胁,以达到保障航运企业安全生产的目的。     

客运专线CTC系统网络安全设计

从客运专线CTC网络安全威胁需求实际出发,根据国家信息安全等级保护有关政策,介绍客运专线CTC网络安全防御体系的系统组成及功能。     

直管站段体制下增加货运保价收入的有效途径

通过对广州铁路集团公司近年来货运保价运输收入下降原因进行分析,采取下放权限,科学制定考核指标,建立有效的考核机制,优质服务,规范管理等各项措施,充分调动直管站段的积极性,有效地扭转了下滑趋势,增加了货运保价收入。     

Effects of the 80 km/h and variable speed limits on air pollution in the metropolitan area of barcelona

In 2008 the regional government of Catalonia (Spain) reduced the maximum speed limit on several stretches of congested urban motorway in the Barcelona metropolitan area to 80 km/h, while in 2009 it introduced a variable speed system on other stretches of its metropolitan motorways. We use the differences-in-differences method, which enables a policy impact to be measured under specific conditions, to assess the impact of these policies on emissions of NO_x and PM₁₀. Empirical estimation indicate that reducing the speed limit to 80 km/h causes a 1.7–3.2% increase in NO_x and 5.3–5.9% in PM₁₀. By contrast, the variable speed policy reduced NO_x and PM₁₀ pollution by 7.7–17.1% and 14.5–17.3%. As such, a variable speed policy appears to be a more effective environmental policy than reducing the speed limit to a maximum of 80 km/h.     

Methodology for kinematic cycle characterization of vehicles with fixed routes in urban areas

This paper analyses the driving cycles of a fleet of vehicles with predetermined urban itineraries. Most driving cycles developed for such type of vehicles do not properly address variability among itineraries. Here we develop a polygonal driving cycle that assesses each group of related routes, based on microscopic parameters. It measures the kinematic cycles of the routes traveled by the vehicle fleet, segments cycles into micro-cycles, and characterizes their properties, groups them into clusters with homogeneous kinematic characteristics within their specific micro-cycles, and constructs a standard cycle for each cluster. The process is used to study public bus operations in Madrid.     

汽车信号灯监测装置的设计

以8031单片机为控制系统,采用金属式应变片传感器和光电耦合器作为检测元件,将检测信号传送到由8031单片机,外加2732芯片构成4KB的外扩展程序存储器和74IS373作为地址锁存器所构成的单片机控制系统,监测汽车信号灯的工作状态.当汽车信号灯出现故障时,通过LED发光二极管和小功率电喇叭发出报警信号.