阿姆斯特丹城市道路线圈检测器布设方法研究

基于宏观基本图(Macroscopic Fundamental Diagram,MFD)的网络交通控制方法受到越来越多的国家的重视,它可以更有效的节约资源和提高效率。然而建立MFD需要以收集网络范围内详细的交通数据为前提,阿姆斯特丹的城市道路错综复杂,若在每个城市道路路段都布设线圈检测器需要巨大的经济支持和维护。基于Vissim的仿真实验的方法,建立阿姆斯特丹的MFD;通过实验方法确定城市道路中对于建立网络MFD起着显著的影响关键路段,为线圈检测器的布设提供了理论依据。     

动态交通信息采集技术比较分析

动态交通信息是ITS各子系统应用的基础和保障,如何获得准确、实时的动态交通信息对ITS的应用效果起着至关重要的作用。因此,有必要在对动态交通信息采集技术进行分类的基础上,对各类动态交通信息采集技术进行比较研究。指出各自的优缺点和适用场合,并对未来的发展方向进行展望。     

舰船水压场频域检测的环境干扰特性分析

舰船水压场以其难于人工模拟性,被作为舰船的重要目标特性广泛应用于水中目标检测中,而对其进行频域检测又是最常用的舰船水压场信号检测方法。复杂多变的海洋环境中,诸多因素都对舰船水压场信号的频域检测性能产生显著影响,文章对在我国沿海不同海域获得的大量环境水压场数据进行分析,得到影响舰船水压场信号频域检测的主要因素,为水中目标探测器设计提供参考。     

Forecasting road traffic conditions using a context-based random forest algorithm

With the ability to accurately forecast road traffic conditions several hours, days and even months ahead of time, both travellers and network managers can take pro-active measures to minimise congestion, saving time, money and emissions. This study evaluates a previously developed random forest algorithm, RoadCast, which was designed to achieve this task. RoadCast incorporates contexts using machine learning to forecast more accurately contexts such as public holidays, sporting events and school term dates. This paper evaluates the potential of RoadCast as a traffic forecasting algorithm for use in Intelligent Transport System applications. Tests are undertaken using a number of different forecast horizons and varying amounts of training data, and an implementation procedure is recommended.     

沥青路面浅层强度探测仪检测参考标准研究

为了使沥青路面浅层强度探测仪SDSAP(Strength Detector of Shallow Asphalt Pavement)能够更好地应用于沥青路面检测评价,针对不同空隙率下的沥青混合料,通过仪器的冲击贯入实验和室内强度试验,初步建立了沥青路面浅层强度探测仪的检测参考标准。     

Length-based vehicle classification using event-based loop detector data

Length-based vehicle classification is an important topic in traffic engineering, because estimation of traffic speed from single loop detectors usually requires the knowledge of vehicle length. In this paper, we present an algorithm that can classify vehicles passing by a loop detector into two categories: long vehicles and regular cars. The proposed algorithm takes advantage of event-based loop detector data that contains every vehicle detector actuation and de-actuation “event”, therefore time gaps between consecutive vehicles and detector occupation time for each vehicle can be easily derived. The proposed algorithm is based on an intuitive observation that, for a vehicle platoon, longer vehicles in the platoon will have relatively longer detector occupation time. Therefore, we can identify longer vehicles by examining the changes of occupation time in a vehicle platoon. The method was tested using the event-based data collected from Trunk Highway 55 in Minnesota, which is a high speed arterial corridor controlled by semi-actuated coordinated traffic signals. The result shows that the proposed method can correctly classify most of the vehicles passing by a single loop detector.     

道路交通网络中移动型检测器最小样本量优化方法研究

本文综合考虑交通流数据的质量及其成本等因素，对服务于ATMS的移动型检测器最小样本量的确定原则进行设计，建立一种基于行程时间估计最小样本量的确定方法，并利用微观仿真模拟软件对城市道路不同服务水平下的交通运行状态进行模拟分析。通过设置不同的检测器样本量方案，并利用优化方法对不同方案采集的交通流信息进行分析，确定合理的移动型检测器最小样本量。     

A low-cost video-based pavement distress screening system for low-volume roads

This study investigates the use of consumer-grade video camera to develop a low-cost pavement distress screening system, with a particular focus on low-volume roads. Due to the oblique view of video data captured in the car front, existing crack detection algorithms that are tailor-made for nadir view cannot be used directly. Instead, we propose and develop a Video-based PAvement Distress Screening (VPADS) system, which includes an automatic data processing workflow by first defining a Region of Interest (RoI) through robust line fitting of the two side lanes. The pavement condition can be assessed within the RoI by implementing a multi-scale ridge detection filter followed by a boundary contour analysis. Since the proposed VPADS system is designed for preliminary screening purpose, each video image scene is examined if there exists any potential crack or distress feature(s). We tested the proposed system on video data collected for two low-volume roads (Highway 624 and 668) in Northern Ontario region, Canada. The overall accuracy of detecting crack and distress features yielded 80%. Instead of replacing traditional field inspection or high-end multi-sensor pavement evaluation system, the proposed VPADS system aims to provide a computer-aided screening solution for transportation authorities of a vast rural road/highway network and with limited inspection budget. The scope of the work can be further expanded by developing a crowdsensing inspection network built by any regular road user, who can also act as a data provider for the regional/municipal pavement distress screening system.     

对射式激光车速检测器在车速采集中的应用方法

该文论述了运用对射式激光车速检测器获取车速数据的观测方法、实施过程,分析了实地测速过程中发现的问题及其解决方法。激光测速方法的可行性、可靠性在实地采集车速的过程中得到了验证。对运用对射式激光测定车速方法的探索,为今后的有关运行车速的研究的数据采集工作提供了方法指南。     

Identification and determination of the major constituents in traditional Chinese medicine Longdan Xiegan Pill by HPLC-D

A novel and sensitive HPLC-UV method has been developed for the simultaneous determination of twelve major compounds in Longdan Xiegan Pill.The chemical profile of the twelve compounds,including geniposidic acid（1）,geniposide（2）,gentiopicroside（3）,liquiri