基于深度强化学习的有轨电车信号优先控制

现有的有轨电车信号优先控制系统存在诸多问题, 如无法适应实时交通变化、优化求解较为复杂等. 本文提出了一种基于深度强化学习的有轨电车信号优先控制策略. 不依赖于交叉口复杂交通建模, 采用实时交通信息作为输入, 在有轨电车整个通行过程中连续动态调整交通信号. 协同考虑有轨电车与社会车辆的通行需求, 在尽量保证有轨电车无需停车的同时, 降低社会车辆的通行延误. 采用深度Q网络算法进行问题求解, 并利用竞争架构、双Q网络和加权样本池改善学习性能. 基于SUMO的实验表明, 该模型能够有效地协同提高有轨电车与社会车辆的通行效率.     

具有公交优先的交叉口信号控制技术

针对一类典型交叉口,提出一种具有公交优先的交叉口模糊信号控制技术。采用公交专用道和公交优先进口道实现公交车辆在空间上的优先,通过具有公交优先的交通信号控制算法实现公交车辆在时间上的优先。信号控制算法的核心模块由绿灯相位模块、红灯相位模块和决策模块组成,分别设计这3个模块的模糊控制策略。控制目标是达到对公交车辆加权的车辆平均延误最小。仿真结果表明,与定时信号控制技术相比,该控制策略不仅大幅度减少了公交车辆的平均延误,而且提高了非公交车辆的通行效率,可应用于实际工程。     

公交优先无线传输系统设计

设计并制作出一款集MC13213控制、射频通信、信号处理等为一体的智能公交嵌入式系统。完全模拟了实际交通中公交进入十字路口、等待交通灯、离开十字路口等过程。系统在平均等待交通灯调度算法的基础上,改进并设计了一种公交优先算法。将在绿灯时间上给予公交车辆以优先权,解决了公交出行缓慢的问题。体现了路权的分配公平性。     

基于相位差渐进循环协调的应急车辆优先信号控制

为了提高应急车辆的通行效率,针对应急车辆需要“绝对优先”路权的特点进行了信号控制的研究,提出了一种基于相位差渐进循环协调的信号控制策略,并将其与应急车辆优先信号配时转换策略相结合进行应急车辆优先信号控制,给出了应急车辆优先信号配时转换控制策略和动态相位差的计算方法。在由三交叉口组成的城市道路系统中,采用三种应急车辆的信号控制策略进行了微观仿真实验,结果表明,文章提出的基于相位差渐进循环协调的应急车辆优先信号控制策略通过对各交叉口相位动态循环渐进微调后,再采用应急车辆优先信号配时转换策略进行控制,可以使应急车辆安全不停车地通过交叉口,且达到了对非应急车辆影响最小的效果。     

车联网环境下的公交自适应优先方法

针对现有公交优先系统中存在的反应滞后、不能够充分挖掘道路通行能力的问题,在车联网的背景下提出一个公交自适应优先（ABP）模型。首先,借助车联网强大的通信能力,利用时分复用的思想,设计了道路复用的控制规则,为普通公交虚拟出了一条专用道,实现了“空间优先”;其次,使用实时获取的车辆到达数据取代历史数据作为交通需求,解决滞后的问题;最后,设计了公交优先的信号控制方法,通过插入短相位的方法让公交优先通行,实现了公交优先。使用VISSIM软件设计仿真实验对比ABP模型和传统模型,结果表明,ABP模型在不对社会车辆造成很大影响的前提下,能够提高公交的运行效率和路口的通过能力。     

单交叉口公交优先双系统模糊控制策略研究

公交系统能够显著地提高城市客运量,有效缓解日益增长的交通需求压力.交叉口公交优先是公交优先发展的一个重要措施,传统的交叉口控制方案将公交车辆与其他类型车辆同等对待,对于载客量较大的公交车辆是不公平的.以人均延误最小为目标,提出了一种单交叉口公交优先的双系统模糊控制模型,其相位模糊控制系统负责对相位方案进行优化,延时抉择模糊控制系统优化各相位的绿灯时间.仿真结果表明,相对于定时控制的公交优先机制,模型在正常交通流的情况下能够有效的减少人均延误.     

考虑相邻交叉口的公交优先信号模型与仿真

在公交系统优先信号模型优化设计中,传统公交信号优先仅考虑公交车辆通过交叉口的影响,而忽视了相邻交叉口所受的影响,因此考虑相邻交叉口通行能力的影响,以总交叉口人均延误为目标,提出以公交优先度作为判别是否优先以及优先程度的决策依据,进而采用绿灯延长和红灯早断两种策略,建立有限的主动优先控制模型.最后,通过VISSIM软件的VAP模块建立仿真模型,并通过案例分析,与无公交优先策略、绝对公交优先策略进行对比分析,结果表明与无公交优先策略相比,所提出的优化控制策略,在中高饱和度下能使总交叉口人均延误平均降低15.7％,在高饱和度下平均降低14.6％.验证了研究成果具有应用价值.     

交叉口BRT实时优先通行控制方法研究

针对交叉口大运量快速公交(BRT)优先通行控制问题,基于智能控制理论提出一种交叉口BRT实时优先通行控制方法.以BRT车辆的延误时间、载客量和非BRT相位社会车辆的排队长度作为神经网络模糊控制器的输入变量,输出BRT通过交叉口的优先等级,以此得到其优先服务方案,有条件地给予BRT车辆的优先通行权.仿真结果表明,与定时控制相比,所提出的方法在交叉口非饱和交通流下,能有效减少BRT车辆通过交叉口的延误时间和停车率,且交叉口的正常交通秩序不受影响.     

交通信号公交优先控制策略及智能控制方法

针对公交优先交通信号控制问题,研究了公交优先的信号控制策略,提出了一种变论域模糊神经网络公交优先智能控制方法.提出了基于相位优先度值的公交优先相位选择方法,并给出了其数学描述.建立了绿灯时间的3层模糊控制模型,分别为红灯排队疏散时间、绿灯延长时间和论域调节因子模糊控制器,其中红灯排队疏散时间和绿灯延长时间两个模糊控制器的输出变量均采用变论域,论域的变化考虑混合交通、天气情况、车流转向等因素由论域调节因子模糊控制器确定.模糊控制器采用粒子群优化神经网络实现.仿真结果表明该方法具有较好的公交优先控制效果.     

交叉口信号实时滚动优化模型及算法

为了合理控制单交叉口交通流并且优先公交,建立可变相序的实时滚动优化模型.该模型将公交优先嵌入优化控制,对每辆公交车实时分配权重系数,以交叉口社会车辆和公交车辆的人均延误最小为目标,优化确定相位序列和相位长度.通过跳相来实现相序优化,运用改进的遗传算法来求解.具体实例表明,可变相序的实时滚动优化模型能有效地减少系统的人均延误,并能在尽量减小对社会车辆的影响下实现公交优先.     

公交优先系统中数据处理及无线联网模块设计

对整个“公交优先”系统实现的功能进行了分析,通过对公交车到达路口的时间进行预估,然后再来对路口控制灯信号进行一定范围的调整,保证公交车能够畅通。该系统功能主要是实现公交信息的读取和对信息的简单处理以及显示,同时使用ZigBee射频芯片的无线路由功能,构建一个信号机与服务器之间的可靠无线网络系统。     

Model-based traffic control

Urban traffic control is a difficult problem because of the complex interdependence of control decisions. Known techniques for achieving global control are based on parameter optimization techniques or heuristic expert systems. Optimization fails in severely congested traffic situations which require a change in global strategy. Heuristic expert systems require knowledge of all possible traffic situations, which is difficult to obtain, especially when construction and incidents cause frequent changes to the traffic network.In this paper, we show how the techniques of model-based diagnosis can be used to select coordinated control plans for networked systems of this kind Suitable local control strategies are those whose underlying assumptions are consistent with other control strategies, the state of the road network, and traffic flow. We describe a system which uses an assumption-based truth maintenance system (ATMS) to compute suitable strategies. The system has been tested both on synthetic examples and on simulations using actual data, and results are encouraging.     

Evaluation of two traffic distribution strategies for adual-network multiprocessor system

The effect of nonuniform traffic patterns is studied based on simulation and analysis when two multistage networks are used in parallel to interconnect processors and memory modules in a shared-memory system. The networks considered are identical copies of buffered multi stage networks. The authors consider the following two strategies to distribute the total traffic between the two networks: distribute the traffic randomly among the networks, and route the nonuniform component of the traffic to one network and the uniform component to the other. To facilitate the implementation of these strategies in a system, a technique to detect nonuniformities in the network traffic at run-time and change the routing strategy dynamically is discussed. The authors compare this technique to an ideal scheme by means of analysis and simulation. The results show that the run-time detection scheme performs very close to the ideal case. The effectiveness of dual networks in tolerating short bursts of nonuniform traffic is also demonstrated     

多信息融合技术的城市交通监控系统的研究

将车辆检测器、射频技术以及计算机图像处理技术应用于城市交通监控系统,形成智能交通的一个子系统.介绍了三种传感器的信息处理和融合技术,能实现交通流量统计、智能交通调控、自动违章处理、车辆跟踪处理、交通实时查询以及车辆统计等功能,解决城市交通管理中的一系列经典难题.     

An intelligent control system for traffic lights with simulation-based evaluation

This paper introduces an intelligent control system for traffic signal applications, called Fuzzy Intelligent Traffic Signal (FITS) control. It provides a convenient and economic approach to improve existing traffic light infrastructure. The control system is programmed on an intermediate hardware device capable of receiving messages from signal controller hardware as well as overriding traffic light indications during real-time operations. Signal control and optimization toolboxes are integrated into the embedded software in the FITS hardware device. A fuzzy logic based control has been implemented in FITS. In order to evaluate the effects of FITS system, this study attempts to develop a computational framework to evaluate FITS system using microscopic traffic simulation. A case study is carried out, comparing different commonly used signal control strategies with the FITS control approach. The simulation results show that the control system has the potential to improve traffic mobility, compared to all of the tested signal control strategies, due to its ability in generating flexible phase structures and making intelligent timing decisions. In addition, the effects of detector malfunction are also investigated in this study. The experiment results show that FITS exhibits superior performance than several other controllers when a few detectors are out-of-order due to its self-diagnostics feature.     

需求激增下交通管理策略仿真分析方法

大型活动时需求激增易引起交通拥挤。本文提出用于评价拥挤应对策略的仿真分析方法。该方法采用宏观交通仿真技术,模拟网络交通流演化过程,分析拥挤成因,以便提出应对策略并验证其有效性。采用GANFreSP仿真系统对一算例路网进行仿真,刻画拥挤发生、传播和消散的过程,并模拟交通系统管理和交通需求管理的拥堵应对策略,给出了路网全局交通状态快照图、交通状态时变轨迹图等可视化结果,及路网总体性能指标。仿真案例表明了该方法在交通控制与管理中的有用性和辅助决策作用。     

一种改进的优先级继承协议及其算法研究

优先级反向是实时系统中由于任务间需要共享资源以及同步而引起的高优先级任务被低优先级任务阻塞的现象。优先级反向使得高优先级任务的执行时间无法预测,增加了实时系统的不确定性。早期的扩展协议较好地解决了优先级反转问题,但同时也存在着自身的不足。针对这些缺陷,在深入研究相关协议的基础上,该文提出了一种改进的优先级继承协议。该协议中信号量按预定义的非循环固定顺序获取,以防止死锁发生,设置超时保护机制,避免任务在获取信号量时长时间的阻塞,给出了关于该协议的分析,并在实时Linux上实现了基于该协议的算法。     

基于GSM短信遥控的交通灯控制系统研究

在城市平交道口设置交通灯是实现交通管理的基本手段之一,为提高城市整体交通的通行效率,不同位置道口的交通灯常需通过控制网络进行集中控制。传统的交通灯控制网络多采用光缆或电缆进行组网,建设和维护成本较高。设计开发了一种基于GSM短信遥控的交通灯控制系统,重点介绍了系统整体结构,以及上、下位机的硬件结构设计方案和软件设计流程。     

Performance analysis of an integrated scheduling scheme in the presence of bursty MMPP traffic

Contemporary communication networks are expected to support multimedia applications which require diversified Quality-of-Services (QoS). An integrated scheduling discipline of Priority Queueing (PQ) and Generalized Processor Sharing (GPS), referred to as P-G, has recently emerged as a promising scheme for cost-effective QoS differentiation. In this paper, we develop a new analytical model for the integrated P-G system subject to bursty traffic. The Markov-Modulated Poisson Process (MMPP) is adopted to capture traffic burstiness because it can qualitatively model time-varying arrival rate and important correlation between inter-arrival times. To derive the desired performance metrics for individual sessions, the integrated P-G system is decomposed into a set of Single-Server Single-Queue (SSSQ) systems. Specifically, the integrated system is first divided into an SSSQ system and a GPS system. Next, a bounding approach is adopted to decompose the GPS system into individual SSSQ systems. Extensive comparisons between analytical and simulation results validate the accuracy of the analytical model. To demonstrate its merits, the model is used to investigate the configuration of the GPS weights under the QoS constraints of different traffic flows.     

Simulation of Railway Traffic Control

Traffic control is the centre of the railway traffic system. The success of a railway traffic simulation model depends very much on an adequate modelling of the traffic control. The main objective of a traffic control system is to minimise delays. Important tasks which contribute to this goal are controlling connections between trains, deciding about priorities and controlling the rotations of crew and rolling stock. In this paper, we discuss a simulation model of railway traffic which is centred around the traffic control functions. It is observed that an object-oriented approach to the modelling of traffic control presents itself as very natural. It results in a very flexible model, which can accomodate a range of present and future traffic control systems. Finally, we present some results of a simulation study that investigates the possibility of partially automating traffic control.