基于状态矩阵的铁路枢纽列流图编制方法

针对铁路枢纽网络结构复杂、列流图绘制工作难度大的特点,研究铁路枢纽列流图的自动编制算法. 根据铁路枢纽内车站连接方向多,列流线在站内交错衔接疏解困难的特点,为车站接入点引入状态矩阵,利用状态变量记录列流线在车站区域的分布状态. 以列车类型作为一级排序,相同类型按列流径路从长到短的次序铺画列流线,借助指示线段实现列流量的标注. 采用所提算法开发了枢纽列流图编制软件,基于枢纽网络图和列车流矩阵,通过人机交互定义车站及连接线布局,实现列流线的快速编制与信息标注. 通过实例证明了算法的有效性和可行性.     

环湖路总体设计方案及思考——以海南省万宁市小海环湖路为例

根据海南省万宁市小海的现状、区位及环境综合治理目标,对小海环湖路的建设条件展开分析,研究环湖路的功能定位,将环湖路分区段展开设计。同时,针对不同区段现状条件及需求,结合道路功能定位展开总体方案设计,可为类似缺乏上位规划条件的环湖道路方案提供相关设计经验。     

功能治理模式在宜昌沙河项目中的应用

城中河湖的治理模式经历了由末端治理向综合治理、系统治理发展的历程。为适应水清、岸绿、景美、城优的环境治理新要求,在上述治理模式的基础上提出了功能治理概念,其优势在于将传统的河湖污染治理与城市发展及市民需求相结合,使环境治理由生态化向人文化转变。该模式在宜昌沙河项目中得到了充分应用,结果表明:对城中河湖而言,以恢复河流相应的城市职能为目标的功能治理模式较单纯的以水质理化指标为治理目标的传统模式有显著的优势。     

中英联锁块铺面质量控制标准对比

联锁块铺面在港区大量使用,经调研发现我国各大港口联锁块铺面质量参差不齐。针对这一问题,对比中英联锁块铺面质量控制及检测相关的标准,得出其异同点。结果表明,中英标虽在联锁块外观质量、尺寸、强度和物理性能指标要求类似,但其抽检方法有所差别;中标缺少联锁块施工质量控制的部分参数要求,对铺面的初期维护和翻修要求也没有明确规定。对中标缺失的部分进行补遗,为新联锁块施工规范制定提供参考。     

城市轨道交通电话闭塞法风险与改进

电话闭塞法是地铁运营中一种必要的行车组织方式。信号系统发生故障后为维持运营而采用的人工控制列车运行的方式,但存在较大的安全风险。通过分析电话闭塞法控制原理,梳理方法中的主要风险点及潜在危害,基于对主要风险的控制,介绍天津市地铁电话闭塞法的基本流程,并针对存在的问题提出改进措施。     

兰州市七里河黄河大桥加固改建方案经济性分析

通过对兰州市七里河黄河大桥主梁更换设计方案比选,简述价值工程的分析方法在工程设计方案比选阶段的应用。     

汽车塑料外观件对整车外观尺寸的影响及控制方法

本文对汽车塑料外观件对整车尺寸的影响和控制方法进行探讨,从塑料翼子板、前后保及前门裙板等外观覆盖件切入,分别从这些零件的材料组成,物理特性,设计制作及装配工艺进行讲述,并与传统钣金覆盖件进行对比,通过分析塑料件在整车装配中实际产生的尺寸问题,制定解决措施并总结经验,为后续车型大面积使用塑料外饰件的尺寸问题解决及零件装配...     

A pedestrian flow model considering the impact of local density: Voronoi diagram based heuristics approach

Local density, which is an indicator for comfortable moving of a pedestrian, is rarely considered in traditional force based and heuristics based pedestrian flow models. However, comfortable moving is surely a demand of pedestrian in normal situations. Recently, Voronoi diagram had been successfully adopted to obtain the local density of a pedestrian in empirical studies. In this paper, Voronoi diagram is introduced into the heuristics based pedestrian flow model. It provides not only local density but also other information for determining moving velocity and direction. Those information include personal space, safe distance, neighbors, and three elementary characteristics directions. Several typical scenarios are set up to verify the proposed model. The simulation results show that the velocity-density relations and capacities of bottleneck are consistent with the empirical data, and many self-organization phenomena, i.e., arching phenomenon and lane formation, are also reproduced. The pedestrians are likely to be homogeneously distributed when they are sensitive to local density, otherwise pedestrians are non-uniformly distributed and the stop-and-go waves are likely to be reproduced. Such results indicate that the Voronoi diagram is a promising tool in modeling pedestrian dynamics.     

A three-dimensional macroscopic fundamental diagram for mixed bi-modal urban networks

Recent research has studied the existence and the properties of a macroscopic fundamental diagram (MFD) for large urban networks. The MFD should not be universally expected as high scatter or hysteresis might appear for some type of networks, like heterogeneous networks or freeways. In this paper, we investigate if aggregated relationships can describe the performance of urban bi-modal networks with buses and cars sharing the same road infrastructure and identify how this performance is influenced by the interactions between modes and the effect of bus stops. Based on simulation data, we develop a three-dimensional vehicle MFD (3D-vMFD) relating the accumulation of cars and buses, and the total circulating vehicle flow in the network. This relation experiences low scatter and can be approximated by an exponential-family function. We also propose a parsimonious model to estimate a three-dimensional passenger MFD (3D-pMFD), which provides a different perspective of the flow characteristics in bi-modal networks, by considering that buses carry more passengers. We also show that a constant Bus–Car Unit (BCU) equivalent value cannot describe the influence of buses in the system as congestion develops. We then integrate a partitioning algorithm to cluster the network into a small number of regions with similar mode composition and level of congestion. Our results show that partitioning unveils important traffic properties of flow heterogeneity in the studied network. Interactions between buses and cars are different in the partitioned regions due to higher density of buses. Building on these results, various traffic management strategies in bi-modal multi-region urban networks can then be integrated, such as redistribution of urban space among different modes, perimeter signal control with preferential treatment of buses and bus priority.     

Comparing and presenting city-level transportation CO2 emissions using GIS

In 2011, the European Pollutant Release and Transfer Register (E-PRTR) inventory of diffuse emissions became available, providing data on a range of atmospheric emissions at a 5 km resolution across Europe. The data are produced from spatially disaggregated emissions totals for countries, and must be validated before being used at a sub-national level. The UK government maintains a 1 km resolution emissions inventory based on a bottom-up methodology by which a validation is possible. The UK National Atmospheric Emissions Inventory data are used to assess at what geographic scale the new E-PRTR data might be most useful. This paper compares the two data sets and estimates city-level transportation CO₂ emissions for 149 EU cities. We find that at a functional boundary level the two datasets match well.