基于约束推理的车站咽喉图型识别及优化设计模型

通用型计算机辅助设计(CAD)软件中不包括铁路车站咽喉平面设计的工具,因此需要研究专业的设计平台。本文认为解决该问题的途径是,首先基于人机交互的图型环境,输入并建立车站咽喉的结构图型,然后通过有效的计算手段识别和判定这种咽喉结构,最后通过结构计算实现车站咽喉平面设计的目标。文章认为模块法比画线法输入咽喉结构图型效率更高,也便于识别。因此,将车站咽喉的基本图形分解为6种基本图元,并对这些图元进行了恰当的描述。应用矢量对接判定条件,识别咽喉结构图型中图元的连接关系。依这种关系,应用约束推理方法和最优化的数学模型,计算满足咽喉设计条件下最优岔心位置坐标和最大平行进路数,从而实现车站咽喉平面设计优化和自动化。     

破解深化产教融合瓶颈探索加快高等职业教育发展路径

本文以行业性高职院校产教融合的实践探索为切入点,以湖北省职业教育改革为例,对中部地区高职教育产教融合的重要举措、存在的问题进行了系统分析,对深化产教融合加快高等职业教育发展提出了相关建议。     

Exact and grid-free solutions to the Lighthill–Whitham–Richards traffic flow model with bounded acceleration for a class of fundamental diagrams

In this article, we propose a new exact and grid-free numerical scheme for computing solutions associated with an hybrid traffic flow model based on the Lighthill–Whitham–Richards (LWR) partial differential equation, for a class of fundamental diagrams. In this hybrid flow model, the vehicles satisfy the LWR equation whenever possible, and have a constant acceleration otherwise. We first propose a mathematical definition of the solution as a minimization problem. We use this formulation to build a grid-free solution method for this model based on the minimization of component function. We then derive these component functions analytically for triangular fundamental diagrams, which are commonly used to model traffic flow. We also show that the proposed computational method can handle fixed or moving bottlenecks. A toolbox implementation of the resulting algorithm is briefly discussed, and posted at https://dl.dropbox.com/u/1318701/Toolbox.zip.     

哈尔滨市西客站地区道路网规划设计

该文首先指出,铁路客运站是城市的重要基础设施,该地区往往成为城市交通的瓶颈所在.接着,介绍了在哈尔滨市铁路西客站的规划建设阶段,对该区域的道路网进行了专门的研究,通过交通需求分析,提出了三种道路网规划方案,并进行了综合评价分析.通过前期的专项的道路网规划设计研究,加强了铁路客运站区域的交通设计,从而有效地避免了诸多后续...     

The Role of Tradable Credit Schemes in Road Traffic Congestion Management

Abstract

Road traffic congestion is not yet reflected in current market prices within the sector and has given rise to a number of instruments to mitigate the resulting negative impacts. The focus of this paper is the tradable credit scheme — an incentive-based economic measure — in order to address traffic congestion. The research questions are (1) whether the state-of-the-art in the literature suggests that tradable credit schemes could be feasibly introduced to mitigate congestion, and (2) whether a tradable credit scheme could have advantages over other instruments. A brief outline of congestion mitigation approaches is provided first to position this type of economic instrument with respect to other measures. The broad issues in the design of a tradable credit scheme are then presented. Most research to date has focused on the use of tradable credits to manage related pollution, but it is clear there is potential to design a scheme for traffic congestion management. To date this is a novel review of tradable credit schemes that has focused specifically on their role in road traffic congestion management.     

山区高速公路移动瓶颈效应对车流状态影响研究

我国高速公路大型货车混入率较高,山区高速公路交通流受移动瓶颈效应影响尤为突出。鉴于此,利用运动学波理论对因低速货车超车形成的移动瓶颈效应进行分析,应用vissim软件进行模拟仿真,通过对不同交通流状态下不同低速货车混入率的仿真结果分析,发现随着交通量以及货车混入率的增加,移动瓶颈效应对车流状态的影响呈加剧趋势,导致小客车行驶速度明显下降,并逐渐接近货车行驶速度。各慢行车队之间出现的较大空隙导致道路资源浪费,道路通行能力下降。该研究结论对深入研究山区道路通行能力具有重要指导意义。     

城市轨道交通网络瓶颈分析

提出了城市轨道交通网络瓶颈的内涵,指出城市轨道交通网络应当将基于能力的技术瓶颈和基于服务水平的服务瓶颈分开研究.提出了网络瓶颈识别、分析和消解方法.以北京城市轨道交通为例,探讨了该方法的适应性,发现服务瓶颈分析能有效地体现网络的供求关系,反映网络不同位置的服务水平,具有较高的应用价值.     

基于M/G/c/c模型的地铁车站楼梯通道疏散能力瓶颈分析

乘客疏散能力及服务水平是地铁车站设计与站内客流组织的重要组成部分,也是保证安全运营的重要影响因素。M/G/c/c网络排队模型适用于各种空间内行人运动过程分析及相应指标的计算。本文在乘客运动特性分析基础上,结合车站空间结构特征,构建基于M/G/c/c的地铁车站楼梯与通道乘客疏散能力瓶颈分析模型。以北京地铁2号线与4号线的西直门换乘站为例开展研究,计算分析该站在乘客到达率发生变化时楼梯、通道的疏散能力瓶颈点,验证模型的有效性与实用性。     

Consistency of Input-Output Model and Shockwave Analysis in Queue and Delay Estimations

This paper investigates the consistency between the simple input-output model and the shockwave analysis method as applied to traffic bottleneck problems. Mathematical derivations considering changes in arriving demand and discharge rate have shown that these models are consistent in queue and delay estimations, as both methods produce identical results at anytime during the congestion propagation and dissipation processes. Earlier findings on the inconsistency of these two methods are attributed to the lack of consideration of the baseline factor, which is dependent on the level of background traffic. Numerical examples are presented to illustrate the importance of the baseline factor, to ensure consistency regardless of the use of different flow-density relationships.