Instantaneous communication throughputs of vehicular ad hoc networks

Vehicular ad hoc networks (VANETs) formed by connected vehicles in a traffic stream could be applied to improve safety, mobility, and environmental impacts of a transportation system. In this paper, we present analytical models for the instantaneous communication throughputs of VANETs to measure the efficiency of information propagation under various traffic conditions at a time instant. In particular, we define broadcast and unicast communication throughputs by the wireless channel bandwith multiplied by the average probabilities that one vehicle is a successful receiver and sender in a VAENT, respectively. With a protocol communication model, we derive formulas to determine the probabilities for an equipped vehicle to be a successful broadcast receiver and a successful unicast receiver/sender, and obtain broadcast and unicast throughputs along discrete and continuous traffic streams. We further examine the impacts on communication throughputs of the transmission range and the interference range of dedicated short range communication devices as well as the market penetration rate of equipped vehicles and the percentage of senders. Finally, we investigate the influence of shock waves on communication throughputs.     

An integrated framework for embedding large-scale dynamic traffic assignment models in advanced traveler information systems

In recent years, increasing attention has been drawn to the development of various applications of intelligent transportation systems (ITS), which are credited with the amelioration of traffic conditions in urban and regional environments. Advanced traveler information systems (ATIS) constitute an important element of ITS by providing potential travelers with information on the network's current performance both en-route and pre-trip. In order to tackle the complexity of such systems, derived from the difficulty of providing real-time estimations of current as well as forecasts of future traffic conditions, a series of models and algorithms have been initiated. This paper proposes the development of an integrated framework for real-time ATIS and presents its application on a large-scale network, that of Thessaloniki, Greece, concluding with a discussion on development and implementation challenges as well as on the advantages and limitations of such an effort.     

The effect of crowding on public transit user travel behavior in a large-scale public transportation system through modeling daily variations

In this paper, the crowding effect in a transit vehicle is modeled in a time-expanded network that considers the daily variation in passenger flows. The study models the daily variation of in-vehicle crowding in a real large-scale transit system. A transit assignment for this real network is modeled and implemented by constructing a crowding cost function that follows the valuation of crowding and by using the reliable shortest path finding method. The direct application of the crowding model to a real network for the Utah Transit Authority indicates that crowd modeling with multi-user classes could influence public transportation system planning and affect the revenues of transit agencies. Moreover, the addition of the disutility factor, crowding, does not always appear to cause an increase in disutility for transit users.     

汽车发动机冷却系统的智能控制

介绍了单片机在汽车发动机智能控制冷却系统的应用,并阐述了智能控制的工作原理。给出了单片机的系统电路原理以及各组成部分的电路图。     

基于大模型的防伪检测技术及其在智能铁路领域的应用进展

各类智能铁路管理系统在运行过程中会产生海量数据,深度伪造技术严重威胁这些数据的真实性,为此,开展针对深度伪造的防伪检测技术及其在智能铁路领域应用进展的研究。文章梳理深度伪造技术及其特点,分析防伪检测方法的研究现状和发展趋势,重点介绍了基于大模型的防伪检测技术研究进展,并比较不同防伪检测技术的优缺点;结合铁路场景特征,分析多模态大模型的应用潜力,构建多模态大模型驱动的防伪检测架构,并指出其在监控识别、调度语音验证、票务身份核验等关键业务场景的技术难点。该研究可为智能铁路防伪检测提供理论支撑。     

������ͨ������Ӫ��֯�����ϵͳ�о�

首先提出了区域运营组织与调度的概念。并对支持区域运营组织与调度的关键技术即运营作业计划自动编织系统的开发,车辆运行定位、监控系统及其支持平台的开发,公交区域运营辅助调度系统和乘客信息服务系统的开发等应用系统及支持平台做了进一步描述。在论文最后,对运营组织与调度区域化的效益进行了分析。     

城市轨道交通运营安全管理 智慧平台建设研究

为提高城市轨道交通运营企业的安全管理水平,设计了安全管理智慧平台,并在乌鲁木齐地铁1号线进行了实践验证.平台以双重预防机制为核心,构建了 10个功能模块,实现了风险预测预警、整体安全态势评估、安全监督检查、应急辅助决策和资源共享等功能.分析结果以可视化图形在平台界面展现,提高了安全生产管理效率,研究成果可以为其他城市轨道交通企业的安全管理数字化建设工作,提供借鉴和参考.     

信号交叉口行人二次过街下右转车通行能力与延误估计模型

在充分分析典型四相位交叉口行人二次过街设置前、后的行人流与右转车流冲突的前提下,以行人过街时间占有率和行人群到达分布作为分析指标,利用可插车间隙理论得出行人单向通行和双向通行条件下的右转车通行能力计算公式;根据行人流随机消散和集中消散的不同特征,应用随机分布理论推导出右转车穿越行人流的延误模型;并通过算例对比分析行人二次过街设置前、后右转车通行能力和延误的变化值。结果表明,除了在少数行人流量比较大的情况下,行人二次过街的设置会小幅度减少右转车的延误;在其他大多数情况下,行人二次过街设置后,右转车的通行能力将受到限制,延误增大,其中,平均通行能力降低了16.68%,平均延误时间增大了21%,所以,当右转车交通需求较大时,需同时考虑行人和右转车的交通运行状态,优化设计是否采用行人二次过街,避免右转车超出极限忍耐时间而增大与行人冲突的概率。     

专家控制−改进S面算法在近水面航行器运动控制中的应用研究

目的旨在提高舵板响应速度和效率,以满足近水面航行器在静水及波浪干扰下的深度保持和姿态控制要求。方法在S面算法的基础上,提出一种具有更快收敛速度的改进S面控制算法,并与专家智能控制相结合,建立闭环专家控制−改进S面算法的混合控制模型,构建混合算法控制器。对比分析PID算法、S面算法、改进S面算法以及专家控制−改进S面算法在近水面航行器航行深度、姿态控制间的差异,并进行波浪干扰下的运动预报。结果预报结果表明：改进S面算法在静水航行控制中可提高收敛速度,波浪干扰下可降低纵摇幅度;专家控制−改进S面算法能够提高舵的控制效率,在静水中快速实现航行状态稳定转换,在波浪中有效降低近水面航行器垂荡和纵摇幅值30%以上。结论所提专家控制−改进S面算法对近水面航行器运动稳定性的提高适用性良好。     

车辆合乘问题的两阶段分布式估计算法

针对智慧交通中多车辆合乘问题,提出一种分布式并行计算环境下的合乘模型. 利用合乘概率矩阵的先验知识,实现更高效的运算和求解.当合乘概率矩阵不是单位 矩阵时,合乘模型被增广为车主合乘和乘客合乘两个阶段.两阶段分布式估计算法运用可行合乘解的合乘概率矩阵,作为一种随机优化方法求解最优值.根据可搭乘矩阵初始化合 乘概率矩阵,并在优化过程中连续更新合乘概率矩阵.车主同乘客分离优化,减少了出行车辆,并实现了互相搭乘的合乘模型.通过合乘模型的优化迭代能够为乘客挖掘出高效可 行的搭乘路线.实验结果表明,该合乘模型具有平均等待时间少、平均载客量大、人均行驶 距离短的高效出行特点.