CBTC移动闭塞信号系统拆分实施方案研究

因城市轨道交通的建设模式影响,后期规划需拆分线路情况屡见不鲜。详细论述在拆分线路中如何实现信号系统拆分的方案。     

New strategies for collision resolution of multi-access channel

ABSTRACT： The truncated binary exponential back-off algorithm is one of the most effective methods applied in collision resolution process of random multi-access channel. In this study, two new strategies are presented to improve the capability of the truncated binary exponential back-off algorithm. In the new strategies, the sizes of the initial window size or the operating window sizes are adjusted dynamically, which always bring a significant improvement for the self-adaptability of the original A series of experiments are simulated and the results verify that the new strategies can make the implementation more stable and effective than the original algorithm.     

基于车流冲突线的无信号交叉口风险分析

为更客观、系统地分析无信号交叉口的安全性能,提出“车流冲突线”概念.通过分析首部车冲突概率、碰撞后严重程度比和冲突向后传递长度,构建无信号交叉口安全风险评估模型.研究表明：基于临界冲突距离值构建的首部车冲突概率模型,考虑两车速度、角度、加速度和反应时间,更接近交通冲突的真实过程;借助物理碰撞学原理可确定 3种冲突型态碰撞严重程度的权重关系,即,交叉∶合流∶分流为 12.705∶1.000∶1.000;利用数学期望知识建立的交叉口当量期望车流冲突量模型,综合考虑冲突发生的潜在机率、交通量大小、车辆位置等因素,可更真实描述实际车流冲突行为.     

基于扩展摩尔邻域的自由飞行冲突风险研究

为解决三维空间中,自由飞行条件下航空器间的飞行冲突风险判定问题,提出了基于扩展摩尔邻域的飞行冲突风险判定方法.首先分析平面摩尔近邻模型的特点,将其扩展至三维离散空间;然后建立水平、垂直飞行冲突风险可能性表格,提出计算三维飞行冲突风险的方法;最后分别用水平、垂直飞行冲突风险分开和同时计算的方法对同一仿真数据进行计算.结果表明:采用扩展的三维不同层摩尔邻域可以实现空域内航空器的飞行冲突风险的快速计算;水平、垂直飞行冲突风险同时计算的方式可以更快速地解决问题;同时,空间基础单元的间隔选择也会极大影响模型的运算效率.     

Traffic conflict models to evaluate the safety of signalized intersections at the cycle level

The safety of signalized intersections has often been evaluated at an aggregate level relating collisions to annual traffic volume and the geometric characteristics of the intersection. However, for many safety issues, it is essential to understand how changes in traffic parameters and signal control affect safety at the signal cycle level. This paper develops conflict-based safety performance functions (SPFs) for signalized intersections at the signal cycle level. Traffic video-data was recorded for six signalized intersections located in two cities in Canada. A video analysis procedure is proposed to collect rear-end conflicts and various traffic variables at each signal cycle from the recorded videos. The traffic variables include: traffic volume, maximum queue length, shock wave characteristics (e.g. shock wave speed and shock wave area), and the platoon ratio. The SPFs are developed using the generalized linear models (GLM) approach. The results show that all models have good fit and almost all the explanatory variables are statistically significant leading to better prediction of conflict occurrence beyond what can be expected from the traffic volume only. Furthermore, space-time conflict heat maps are developed to investigate the distribution of the traffic conflicts. The heat maps illustrate graphically the association between rear-end conflicts and various traffic parameters. The developed models can give insight about how changes in the signal cycle design affect the safety of signalized intersections. The overall goal is to use the developed models for the real-time optimization of signalized intersection safety by changing the signal design.     

交换机中报文三层转发的分布式处理研究与实现

随着芯片处理能力的迅速提高，交换机内部由报文转发机制所造成的瓶颈亟需解决。介绍了在华为新型（S6500系列）交换机上实现报文三层转发的分布式处理系统的原理，详述了分布式交换机对整机三层转发表的维护机制及ARP的分布式处理和表项同步机制。     

有机静电感应三极管（OSIT）静态工作特性的解析

在分析SIT器件电流一电压特性的理论基础上，对由有机半导体材料酞氰铜制作的有机SIT进行了静态特性的测试，通过对测试曲线进行数据拟合与解析，得出一系列OSIT在不同偏压条件下，电流-电压的表达式．数据解析结果表明，有机SIT器件的静态特性同无机SIT器件静态特性的理论分析基本相符。     

城市道路路段和交叉口阻抗函数探讨

城市道路的路阻函数是交通研究中的关键点和难点．对交通分配起着至关重要的作用。本文先对城市道路路段阻抗函数进行细致的分析，通过实际调查的数据对该函数进行了验证。对信号交叉口的路阻函数进行了比较详细的分析，提出了隐性冲突点的概念，对信号交叉口阻抗函数中添加了与流向有关的心理参数项，并进行了分析和标定。     

浅析DR67对耙吸挖泥船完整稳性的要求

入CCS级有允许耙吸挖泥船采用减小干舷的趋势,但是完整稳性要按照DR67决议计算.通过计算分析,探讨了DR67对完整稳性计算的要求,对这些要求应予以满足,也是当前国内耙吸式挖泥船设计在稳性计算中函待解决的问题.     

路段交通冲突技术研究

对路段交通冲突进行定义和分类，着重研究严重冲突的判别标准和分级标准是对现有交通冲突技术理论的一种完善和改进，为路段交通安全分析评价提供一种新的研究途径。