智能交通系统综合信息平台研究

分析了综合交通信息平台数据处理、交互平台和辅助决策等主要功能，在此基础上提出了以多种数据处理技术为核心的综合交通信息平台的分布式体系结构，探讨了综合交通信息平台建设的数据融合技术、数据压缩技术、数据标准、数据仓库技术以及数据挖掘技术等，该综合信息平台的具有实现交通运输系统的有效集成、交通运输服务内容的延伸等优越性。     

Urban Traffic Flow Prediction Using a Spatio-Temporal Random Effects Model

Traffic prediction is critical for the success of intelligent transportation systems (ITS). However, most spatio-temporal models suffer from high mathematical complexity and low tune-up flexibility. This article presents a novel spatio-temporal random effects (STRE) model that has a reduced computational complexity due to mathematical dimension reduction, with additional tune-up flexibility provided by a basis function capable of taking traffic patterns into account. Bellevue, WA, was selected as the model test site due to its widespread deployment of loop detectors. Data collected during the 2 weeks of July 2007 from 105 detectors in the downtown area were used in the modeling process and traffic volumes predicted for 14 detectors for the entire month of July 2008. The results show that the STRE model not only effectively predicts traffic volume but also outperforms three well-established volume prediction models, the enhanced versions of autoregressive moving average (ARMA) and spatiotemporal ARMA, and artificial neural network. Even without further model tuning, all the experimental links produced mean absolute percentage errors between 8% and 16% except for three atypical locations. Based on lessons learned, recommendations are provided for future applications and tune-up of the proposed STRE model.     

Solving the K-shortest paths problem in timetable-based public transportation systems

Finding the K-shortest paths in timetable-based public transportation systems is an important problem in practice. It has three typical variants: the K-earliest arrival problem (K-EAP), the K-shortest travel time problem (K-STTP), and the K-minimum number of transfers problem (K-MNTP). In this article we show that these problems can be solved efficiently by first modeling the timetable information with the time-expanded approach, then applying the Martins and Santos (MS) algorithm. Then we model the timetable information with the time-dependent approach and propose a modified version of the MS algorithm for solving the K-EAP. Experimental results on real-world data show that for K smaller than 100, which is enough for most applications, the execution times of the MS algorithm for the problems in the time-expanded model are less than 100 ms on a server with a 1.86-GHz central processing unit (CPU) and 4 GB of memory. For solving the K-EAP the modified MS algorithm in the time-dependent model is even more efficient (about three times faster for K ≤ 100) than the original algorithm in the time-expanded model. Our results imply the great potential of the MS algorithms in practical transportation service systems.     

多Agent在铁路供电设备状态管理系统中的应用

现有铁路供电管理信息系统只是将信息汇总,方便用户浏览,多数不具有分析功能。为此,提出一种将多Agent技术应用于供电MIS的方法,并以铁路供电管理信息系统设备状态监测子系统为例,论述系统的层次结构和工作流程、各个Agent的功能部署和协作机制、系统的优缺点。     

内河搜救应急管理信息系统总体架构设计及应用

文中介绍了搜救应急管理的业务流程,提出了基础层、数据层、支撑层、应用层和展现层的水上搜救应急管理信息系统总体架构设计,结合湖北省水上搜救应急管理系统“数据中心、两级搜救平台、三大应用系统”的建设情况,介绍了系统建设和应用效果。     

Empirical assessment of urban traffic congestion

This paper presents an empirical assessment of urban traffic congestion in Central London, UK. Compared with freeways or motorways, urban networks are relatively less studied because of its complexity and availability of required traffic data. This paper introduces the use of automatic number plate recognition technology to analyze the characteristic of urban traffic congestion in Central London. We also present the use of linear regression to diagnose the observed congestion and attribute them to different causes. In particular, we distinguish the observed congestion into two main components: one due to recurrent factors and the other due to nonrecurrent factors. The methodologies are illustrated through a case study of Central London Area. It is found that about 15% of the observed congestion in the region is due to nonrecurrent factors such as accidents, roadwork, special events, and strikes. Given the significance of London, the study will be valuable for transport policy evaluation and appraisal in other global cities. Copyright © 2013 John Wiley & Sons, Ltd.     

基于物元理论的公路隧道衬砌结构技术状况评估模型

为了评估施工期高速公路隧道衬砌结构技术状况,文章运用层次分析法建立由目标层、因素层和指标层构成的递阶层次结构模型,分析影响隧道衬砌结构的各种不确定性因素;采用物元理论、模糊集合论和信息熵理论,构建熵权模糊物元评估模型.工程实例应用结果表明,交工前隧道结构技术状况为IA,衬砌破损程度等级为一般;衬砌裂缝和衬砌背后空洞是影响评估结果的最主要因素.研究认为:该评估方法考虑了指标因子的不确定性,将主观权重与客观权重相结合,避免了传统评判方法中的主观随意性,所得结果更加符合客观实际.     

武汉市交通规划信息系统构建及应用

针对当前交通规划海量数据多源异构、数据源分散、无统一平台管理及数据获取困难等问题,提出建立基于GIS及交通规划思想与技术的交通规划信息系统。拟定了整体架构,提出了从整体上规划和设计架构于子系统的开发模式,制定了适用于交通规划的数据结构,明确了数据对象间的相互关系,实现了GIS信息系统与EMME3模型的数据交换与集成,总结了关键问题及其处理方法。最后,通过实践应用,阐述了系统在交通规划及建设中的重要作用。     

Sight distance analysis of highways using GIS tools

Analyzing the distance visible to a driver on the highway is important for traffic safety, especially in maneuvers such as emergency stops, when passing another vehicle or when vehicles cross at intersections. This analysis is necessary not only in the design phase of highways, but also when they are in service. For its use in this last phase, a procedure supported by a Geographic Information System (GIS) has been implemented that determines the highway distances visible to the driver. The use of a GIS allows the sight distance analysis to be integrated with other analyses related to traffic safety, such as crash and design consistency analyses. In this way, more complete analyses could be made and costs shared. Additionally, with the procedure proposed it is possible to use data regarding the trajectory of a vehicle obtained on a highway with a Global Positioning System (GPS) device. This application is very useful when highway design data are not available. The procedure developed and its application in a case study are presented in this article.     

城市轨道交通乘客信息系统的发展

随着城市轨道交通的不断发展和信息技术的进步,城市轨道交通乘客信息系统（PIS）越来越作为一个独立的系统出现在城轨建设中,以提高运营效率和服务水平。本文对PIS系统做了简单的总结,并对其发展进行了展望。