一种用于多摄像机无重叠视域环境下的车辆跟踪系统

针对当前交通监控系统中自动化程度较低、过多依赖人力进行监控的现状,文章设计了一种用于多摄像机无重叠视域环境下的车辆跟踪系统.该系统为中心-分布式结构,中心服务器与分布在前端的智能摄像机节点通过GPRS相连,与传统的功能单一的摄像头相比,基于DM642的智能节点可以在前端完成目标检测、跟踪以及分类等工作,并将抽象化后的目标特征信息通过GPRS传输给中心服务器,大大减轻了网络传输的压力.中心服务器根据节点传送来的目标信息,对不同摄像机视域下的目标进行匹配,实现了目标的连续跟踪,获得了更为全面的目标信息.试验表明,文章设计的车辆跟踪系统可以在较大监控范围内有效地跟踪目标车辆.     

城市客车驱动系统优化匹配节油五步法

本文概要阐述城市客车驱动系统优化匹配节油的方法和步骤.其方法的核心是选择合适的发动机、变速器、驱动桥、轮胎的特性参数,在满足动力性能的同时节油.     

铁路单线特长隧道快速施工组织探究

蒙华铁路连云山隧道为重载铁路单洞单线隧道,独头掘进距离长、断面小,洞内施工交通干扰大,隧道快速施工组织难度高。为有效解决单线小断面隧道快速施工组织问题,基于隧道开挖、仰拱及二次衬砌各施工工序组织,对配套施工机械设备、工艺工法选择和施工交通组织等进行研究。通过优化和改进,较大程度上解决了单线特长隧道的快速施工难题,有效提高了单线隧道的施工效率。     

一种基于物影匹配算法的道路小目标跟踪方法

针对复杂道路环境下小目标抛洒物难以被检测与跟踪，且落地静止像素易被纳入背景而导致目标丢失等问题，本文提出一种基于物影匹配算法(OSMA)的道路小目标跟踪方法来解决上述问题。首先，采用混合高斯模型对背景进行建模以此获取前景图像，对前景图像采用膨胀、腐蚀等形态学处理；其次，根据道路抛洒物移动时在前景产生独立的物与影双轮廓特征，进行连续帧前景轮廓的物影匹配，并将连续的匹配结果定为疑似抛洒物；最后，采用多帧质心偏移法判断疑似抛洒物是否处于静止状态，并对运动状态中的疑似抛洒物进行位置判定与帧间轮廓匹配，从而实现抛洒物的逐帧跟踪。基于大量实验表明：本文所提出的OSMA与核化相关滤波器(KCF)、辨别尺度空间跟踪器(DSST)、背景感知相关滤波器(BACF)、深度注意力跟踪器(DAT)、视觉跟踪时空变换器(SATRK)等跟踪器相比，准确性更优越，可较好解决道路复杂场景下各类抛洒物的跟踪问题；复杂背景、快速旋转的小目标场景中跟踪表现优异，具有良好的跟踪尺度，实时性满足预期要求。     

Estimating the most likely space–time paths,dwell times and path uncertainties from vehicle trajectory data: A time geographic method

Global Positioning System and other location-based services record vehicles’ spatial locations at discrete time stamps. Considering these recorded locations in space with given specific time stamps, this paper proposes a novel time-dependent graph model to estimate their likely space–time paths and their uncertainties within a transportation network. The proposed model adopts theories in time geography and produces the feasible network–time paths, the expected link travel times and dwell times at possible intermediate stops. A dynamic programming algorithm implements the model for both offline and real-time applications. To estimate the uncertainty, this paper also develops a method based on the potential path area for all feasible network–time paths. This paper uses a set of real-world trajectory data to illustrate the proposed model, prove the accuracy of estimated results and demonstrate the computational efficiency of the estimation algorithm.     

Transitioning to energy efficient vehicles: An analysis of the potential rebound effects and subsequent impact upon emissions

Given the shift toward energy efficient vehicles (EEVs) in recent years, it is important that the effects of this transition are properly examined. This paper investigates some of these effects by analyzing annual kilometers traveled (AKT) of private vehicle owners in Stockholm in 2008. The difference in emissions associated with EEV adoption is estimated, along with the effect of a congestion-pricing exemption for EEVs on vehicle usage. Propensity score matching is used to compare AKT rates of different vehicle owner groups based on the treatments of: EEV ownership and commuting across the cordon, controlling for confounding factors such as demographics. Through this procedure, rebound effects are identified, with some EEV owners found to have driven up to 12.2% further than non-EEV owners. Although some of these differences could be attributed to the congestion-pricing exemption, the results were not statistically significant. Overall, taking into account lifecycle emissions of each fuel type, average EEV emissions were 50.5% less than average non-EEV emissions, with this reduction in emissions offset by 2.0% due to rebound effects. Although it is important for policy-makers to consider the potential for unexpected negative effects in similar transitions, the overall benefit of greatly reduced emissions appears to outweigh any rebound effects present in this case study.     

电动汽车动力电源系统DC／DC变换器的匹配和计算

介绍新能源汽车DC／DC变换器在实际应用中的匹配、选型思路及方法。     

交流发电机试装车中问题的几点分析

介绍交流发电机在试装车匹配中碰到的几个问题,结合实践,阐述解决思路。     

感应线圈电路分析

通过把感应线圈等效成由直流电阻、电感、分布电容组成的电路，来分析它对零输入和正弦信号响应。同时分析了匹配电阻对感应线圈棒性能的影响，并通过试验分析验证了在感应线圈棒谐振点处接收信号的可行性。     

CHN60轨与59R2槽型轨对现代有轨电车轮轨匹配性能的影响分析

为研究CHN60钢轨型面、59R2钢轨型面与现代有轨电车不同磨耗车轮型面的匹配性能,对国内一现代有轨电车车轮型面进行现场测量,将运行不同里程后磨耗车轮型面分别与CHN60钢轨型面、59R2槽型轨型面在对中位置进行型面匹配,建立轮轨弹塑性接触有限元模型,对有轨电车轮轨接触的Mises应力、接触状态进行了研究。研究结果表明:新车轮与CHN60钢轨、59R2槽型轨匹配的最大等效应力相差不大;随着运行里程的增加,磨耗车轮与CHN60钢轨、59R2槽型轨匹配的最大等效应力先增加后减少;有轨电车磨耗车轮与59R2槽型轨匹配的接触斑面积大,最大等效应力小,且形状更接近于椭圆形,轮轨匹配性能较好。