沥青加热方法及导热油的脱水升温工艺

分析了几种沥青加热方法,通过对比得出导热油加热沥青被广泛运用的原因,并详细介绍了导热油脱水升温时应采取的工艺和注意的问题.     

可直接计算转向流量的改进型DIAL交通分配算法

为了在交通分配中直接计算转向流量而不是通过事后推算获取,利用转向—路段拓扑关系及其衍生路段上流量守恒的规律,对Logit交通分配中最常用的DIAL算法进行改进。改进后的DIAL算法既继承了原算法的基本结构和全部优点,又可在得到路段流量的同时直接计算转向流量,且能避免传统的FURNESS、FRATOR等事后推算模型在进行路段流量至转向流量迭代推算时的过大计算量及其他缺点。最后通过一个经典算例验证了该算法的有效性。     

北京机场线无人驾驶模式系统的研究与实践

北京机场线是国内首条采用无人驾驶技术的地铁线路。阐述北京机场线无人驾驶系统采用基于通信的列车控制系统的结构与性能,重点分析无人驾驶系统的技术应用,对无人驾驶系统投入运营的情况进行相关介绍。     

事故多发点鉴别本质及基于BP神经网络的鉴别方法研究

首先对常规事故多发点鉴别方法进行了分析和评述,并通过实例揭示了多发点的鉴别本质。在此基础上,建立了基于三层BP神经网络的城市干道路段事故多发点鉴别模型。该模型考虑了交通事故7个方面的影响因素,并能将常规鉴别方法不易识别出的多发点鉴别出来。其次,应用哈尔滨市市区430个干道路段上1999年至2004年发生的13764起交通事故数据及关联因素数据,对神经网络的权值和偏置值进行了标定,并应用该模型进行了事故多发路段鉴别。最后,分别应用了事故次数概率分布法、矩阵法和质量控制法对430个路段进行了多发点鉴别,并对鉴别结果进行了对比分析。     

基于FCD的旅行时间估计算法研究

根据FCD(Floating Car Data浮动车数据)的特点建立基于FCD旅行时间估计的Kalman滤波模型以及BP神经网络模型,运用上述两种模型进行路段旅行时间短时预测,路段平均旅行时间为输入变量,输出预测路段的旅行时间,并用实测数据进行分析验证.结果表明,针对路段短时旅行时间估计,Kalman滤波模型方法的预测精度要优于BP神经网络方法.     

Estimating arterial link speed using conventional road detectors

Abstract

In response to an initiative to develop an advanced traffic information system in Bangkok, this paper explores practical guidelines for the optimal location of road sensors, such that the data collected on spot speeds reflect an entire link's average speed. In particular, the authors use microsimulation software to investigate optimal detector locations, using the sum of squared errors and root mean squared errors. The analysis hypothesizes that road segments are 0.4, 0.6, 0.8, 1.0, 2.0 and 3.0 km in length and are specially designed to replicate typical arterial streets in Bangkok. The results show that a single detector location can produce good estimates of link speed only for segments that are shorter than 1.0 km. For distances of 1.0 km or more, the results suggest that two detectors be used for good link speed estimates under all traffic conditions.     

How tube strikes affect macroscopic and link travel times in London

Abstract

The purpose of this study was to investigate the impact of the five strikes on the London Underground (metro) rail system, which occurred in 2009 and 2010, on macroscopic and road link travel times. A consequence of these strikes was an increase in road traffic flows above usual levels. This provides an opportunity to observe the operation of the road network under unusually high flows. The first objective involves the examination of strike effects on inbound (IT) and outbound traffic (OT) within central, inner and outer London. Travel time data obtained from automatic number plate recognition cameras are used within the first part of the analysis. The second more detailed objective was to investigate in spatio-temporal effects on travel times on five road links. Correlation analyses and general linear models are developed using both traffic flow and travel time data. According to the results of the study, the morning IT had approximately twice as much delay as the OT. Central London experienced the highest delays, followed by inner and outer London. As would be expected, the unique full-day strike in 2009 yielded the worst impact on the network with the highest percentage increase in total travel time (60%) occurring during the morning peak in the IT in inner London. The results from the link-level analysis showed statistical significance amongst the examined links indicating heterogeneous effects from one link to another. It was also found that travel time changes may be more effectively captured through time-of-day terms compared to hourly traffic flows.     

A framework for neighbour links travel time estimation in an urban network

This paper proposes a solution to the problem of limited network sensor coverage caused by insufficient sample size of probe vehicles or inadequate numbers of fixed sensors. A framework is proposed to estimate link travel times using available data from neighbouring links. Two clues are used for real-time travel time estimation: link historical travel time data and online travel time data from neighbour links. In the absence of online travel time data from neighbour links, historical records only have to be relied upon. However, where the two types of data are available, a data fusion scheme can be applied to make use of the two clues. The proposed framework is validated using real-life data from the City of Vancouver, British Columbia. The estimation accuracy is found to be comparable to the existing literature. Overall, the results demonstrate the feasibility of using neighbour links data as an additional source of information that might not have been extensively explored before.     

基于路段风险度的城市危险品运输路径优化选择

以减少运输路径沿线发生事故的风险及减少事故发生后对城市交通的影响为目的,利用交通流理论研究城市危险品运输路径的选择问题.首先利用传统风险管理理论对路段发生事故的风险及发生事故后的交通损失进行分析,提出了路段风险度的定义;利用Dial算法对路段的损失幅度进行计算,从而得到各路段的风险度,建立了风险度最小的危险品运输路径选择模型;然后利用传统标号算法设计了该模型的求解方法;最后通过算例分析了路段交通量与其风险度的关系,得出路段的交通量与路段风险度之间的关系.     

自升式钻井平台安全承载检测系统研究

自升式钻井平台属于海上移动式平台,由于定位能力强和作业稳定性好,在大陆架的勘探开发中居主力军地位。而自升式钻井平台的重要系统齿轮齿条升降机构是自升式平台的重要承载机构, 在各种工作状态下起到支撑船体及相关设备的作用, 并长时间承受重外载荷作用。因而,对齿轮齿条升降系统的检测直接关系到平台的作业安全,本文从平台结构入手探索一种适合自升式钻井平台的安全监测系统实施检测平台关键部分的受力状况为作业安全、生产指挥、寿命评估等提供技术依据。