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991.
Traffic flow pattern identification, as well as anomaly detection, is an important component for traffic operations and control. To reveal the characteristics of regional traffic flow patterns in large road networks, this paper employs dictionary-based compression theory to identify the features of both spatial and temporal patterns by analyzing the multi-dimensional traffic-related data. An anomaly index is derived to quantify the network traffic in both spatial and temporal perspectives. Both pattern identifications are conducted in three different geographic levels: detector, intersection, and sub-region. From different geographic levels, this study finds several important features of traffic flow patterns, including the geographic distribution of traffic flow patterns, pattern shifts at different times-of-day, pattern fluctuations over different days, etc. Both spatial and temporal traffic flow patterns defined in this study can jointly characterize pattern changes and provide a good performance measure of traffic operations and management. The proposed method is further implemented in a case study for the impact of a newly constructed subway line. The before-and-after study identifies the major changes of surrounding road traffic near the subway stations. It is found that new metro stations attract more commute traffic in weekdays as well as entertaining traffic during weekends.  相似文献   
992.
The proactive operational strategy in the transport system which is a parallel concept associated with the Intelligent Transportation System (ITS) seems to be modern and right direction of development. However, the basis for its operation is the “information” in the broad sense of the term, on the functioning of the transport system itself. As new technologies develop, there emerge new opportunities of putting to use a wide array of sensors which can deliver more complete traffic data but using complex matrix of sensors is often unjustified economically and confusing. The paper proposes use of magnetometers as an interesting alternative to pass the requirements of simplicity of application, minimum costs and maximum of acquired information. The process of obtaining the information requires analysis of the quantitative and qualitative changes of the magnetic field. The conducted analyses demonstrate the possibility of using the passive magnetic methods for the purpose of monitoring of vehicles. Placement of the magnetic sensor bear out an important issue and was also discussed. During the experimental research it has been proven that passive magnetic methods enable obtaining the information on the movement of a vehicle as well as on the vehicle itself. Estimations of such values as: vehicle’s moving direction, velocity, dimensions, clearance or mass having ferromagnetic properties and even the state of strain in a vehicle’s structure were confirmed in practice. In addition thanks to magneto-mechanical effects the theoretical possibility of assessing the stress occurring in the components of vehicles, which could be indicative of the volume of cargo carried. Moreover, the crash experiment showed the possibility of a collision detection using magnetic signal. The need for obtaining information increases from year to year, with information becoming the biggest asset which enables both development and effective use of the transport system. Included researches, proofs emerging opportunity of more extensive use of magnetic sensors and the passive magnetic methods which could be applied in the modern transportation system.  相似文献   
993.
针对目前传统的机车信号测试环线安装在钢轨内侧腰部存在一定的磁屏蔽、安装相对不是很容易、施工钢轨穿孔困难等缺点,结合具体施工等实际因素,设计并实现了一种成本较为低廉、安装方便、削弱构成磁屏蔽的一种机车信号测试环线支架法。该方法采用自主设计,特定加工的环线支架固定在钢轨上,环线通过支架安装在钢轨外侧,高度基本与钢轨高度水平。实践证明,这种环线支架法较之前传统的安装方式使用效果良好、信号检测稳定,设计经过实践检验基本合理,能满足机车信号的正常检测,在一定程度上优化了设计,方便了施工,达到了预期目标。  相似文献   
994.
针对传统信号灯检测方法中存在的弊端,提出了一种主成分分析(Principal Component Analysis,PCA)和圆拟合与分段随机Hough变换(Randomized Hough Transform,RHT)圆检测相结合的信号灯检测方法。该方法利用主成分分析结合圆拟合来简化图像的复杂背景,然后通过随机Hough变换进行分段圆检测,得到信号灯的准确位置,最后结合线路特征及信号灯的颜色特点,确定本股道有显示的调车信号灯。对调车信号灯图像进行仿真实验,结果表明,该方法检测准确度高,实时性好,并对有颜色信号灯的检测具有良好的检测效果,适合于对复杂环境中调车信号灯的准确检测和定位。  相似文献   
995.
由于桥梁的先天弱点和老化现象等原因,对桥梁进行检测,建立合适的评估方法已成为当务之急。明确桥梁状态检测评估的内容与依据,对桥梁外观、材料、结构等的检测评估进行探讨。  相似文献   
996.
在目前应用的机动车视频违法检测系统中,广泛采用的是多摄像机分别拍摄违法行为全景及违法车辆车牌特写的技术方案。针对其存在证据性弱、系统调试复杂等缺点,设计并实现了一种基于高分辨率摄像机的视频违法检测系统,重点阐述了系统设计方案、软件结构、实现方法和实验结果。  相似文献   
997.
为了适应高速铁路联调联试的要求,在不影响正常行车的情况下完成对道岔转换设备的相关检测,提出一种移动检测车的设计方案,采用自动测控、计算机网络、视频采集等技术手段,对高速铁路道岔转换设备的应力、振动、位移、电流、同步性能等参数进行全面检测.经实际现场应用,移动检测车在联调联试过程中取得了良好效果.  相似文献   
998.
Outliers in traffic flow series represent uncommon events occurring in the roadway systems and outlier detection and investigation will help to unravel the mechanism of such events. However, studies on outlier detection and investigations are fairly limited in transportation field where a vast volume of traffic condition data has been collected from traffic monitoring devices installed in many roadway systems. Based on an online algorithm that has the ability of jointly predict the level and the conditional variance of the traffic flow series, a real time outlier detection method is proposed and implemented. Using real world data collected from four regions in both the United States and the United Kingdom, it was found that outliers can be detected using the proposed detection strategy. In addition, through a comparative experimental study, it was shown that the information contained in the outliers should be assimilated into the forecasting system to enhance its ability of adapting to the changing patterns of the traffic flow series. Moreover, the investigation into the effects of outliers on the forecasting system structure showed a significant connection between the outliers and the forecasting system parameters changes. General conclusions are provided concerning the analyses with future work recommended to investigate the underlying outlier generating mechanism and outlier treatment strategy in transportation applications.  相似文献   
999.
在国内外弓网燃弧检测技术研究的基础上,研究分析了弓网燃弧的光谱特性,成功研制了基于紫外脉冲原理的非接触式弓网燃弧检测系统。利用该检测系统对广州地铁3号线北延伸段频繁出现弓网拉弧现象进行实时检测,并对检测数据进行分析,探讨了刚性悬挂条件下建立弓网关系评价体系的思路,为以后的线路维护及改造提供理论参考。  相似文献   
1000.
IntroductionAnedgeinanimagemaybedefinedasarapidgraychangeintheregisteredintensityvalues.Themostnaturalwaytodetectchangesinthe...  相似文献   
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