地铁联络通道涌水涌砂治理技术研究

针对西安地铁联络通道施工过程中出现的涌水涌砂情况,从地层、坑底突涌稳定性验算,旋喷桩加固、降水井施工等多方面进行了分析,并制定了相应的方案,即通过初支加固、涌水点多次反压,增设降水井、组合浆液注浆、监测等方式进行处理,涌水得到了有效控制,并确保了后续未完成工程的安全。     

道路运输车辆达标车型整车主动安全项目测试简析

道路运输车辆达标车型的实施,有效提升了道路运输车辆的安全性能。文章主要从电子稳定性控制系统、车道偏离预警系统、前向碰撞预警系统、自动紧急制动系统四个整车主动安全测试项目对道路运输车辆达标车型相应标准进行介绍,为道路运输车辆达标车型相关从业人员提供了主动安全整车项目试验参考。     

Towards data-driven car-following models

Car following models have been studied with many diverse approaches for decades. Nowadays, technological advances have significantly improved our traffic data collection capabilities. Conventional car following models rely on mathematical formulas and are derived from traffic flow theory; a property that often makes them more restrictive. On the other hand, data-driven approaches are more flexible and allow the incorporation of additional information to the model; however, they may not provide as much insight into traffic flow theory as the traditional models. In this research, an innovative methodological framework based on a data-driven approach is proposed for the estimation of car-following models, suitable for incorporation into microscopic traffic simulation models. An existing technique, i.e. locally weighted regression (loess), is defined through an optimization problem and is employed in a novel way. The proposed methodology is demonstrated using data collected from a sequence of instrumented vehicles in Naples, Italy. Gipps’ model, one of the most extensively used car-following models, is calibrated against the same data and used as a reference benchmark. Optimization issues are raised in both cases. The obtained results suggest that data-driven car-following models could be a promising research direction.     

Development of control models for the planning of sustainable transportation systems

Planning of sustainable transportation systems requires integration of multiple systems while considering a holistic approach. A limited amount of research has been conducted that simultaneously considers all the transportation, economic activity, environmental and social effects. The proposed research envisages incorporating considerations related to sustainability and providing solutions to stakeholders in policy making. In this paper, a dynamic model for planning and development of sustainable transportation systems is presented. This is given by a system of three nonlinear differential equations representing the dynamics of the three independent states, namely, transportation, activity, and environmental systems. A policy scenario considering investment in energy efficient technologies and its effects on the states is discussed to assist making investment decisions. Optimal control techniques are used to design the controls. The results show that it is possible to formulate an optimal control to achieve the desired target. Numerical results, based on actual parameters, are presented to illustrate the long-term trends of the states. The methodology discussed in this paper will be helpful to decision makers in making optimal decisions. The contribution of this research work is the introduction of a systems and controls methodology to develop optimal policies for the design of sustainable systems.     

多模型交通流预测优化

根据当前交通流预测模型发展的情况,提出采用卡尔曼滤波模型、指数平滑模型和非参数回归模型进行预测融合的方法,该方法在提高系统预测速度的基础上也能提高预测精度,因此,具有很好的推广价值.     

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本文建立了动态用户最优（DUO）配流问题的双层变分不等式（VI）模型，该模型能够同时选择出发时间和路径，使得乘客在任意时刻都能够选择负效用最小的出发时刻和阻抗最小的路径。文中用基于混沌优化分析的算法来求解这个双层变分不等式模型，其结果不仅能够告诉出行者应该在什么时刻出发，而且还能够计算每个小时段的路段流入率、流出率及路段流量，从而达到对行人进行诱导的目的。     

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通过对一次制动模式曲线列控方式的剖析，阐述了在确定列车追踪时间间隔时传统公式使用平均速度进行计算所存在的弊端，从而提出了利用计算机仿真技术对一次模式曲线列控方式下的追踪时间间隔及其对应模式曲线的生成进行模拟计算，并针对该模拟计算提出了相应的模型与算法；同时，基于追踪时间间隔一般情况下受限于车站到达间隔的事实，对列车进站进行了提前减速的优化设计，并提出了相应的模型流程。最后，针对前述研究作了实例验算。     

高速列车开行方案研究

对高速列车停站影响进行了分析，建立了高速列车开行主案的多目标０－１规划数学模型，研究了一套有效可行的多层次０－１规划模型，这用有序组全树方法对问题求解。     

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熵最大化方法被广泛应用于交通规划，为交通需求预测模型提供了理论依据.本文使用信息论中的熵概念描述居民出行分布，并根据最大信息熵理论提出了基于原点矩典型特征量约束条件下的出行分布模型，详细阐述了模型中各个参数的实际含义，该模型是一个普适性模型，其具体形式决定于最高阶原点矩阶数的取值，此值对模型精度及参数标定难易程度有重要影响.为确定模型参数，提出了实用的参数标定方法.由于模型中原点矩的最高阶数对模型精度有较大影响，为找到两者之间的关系，利用长春市出行调查数据研究了四种出行方式分别时应于五种原点矩最高阶数的模型拟合情况.因文中所建立的模型是一系列模型，为比较其描述问题的优劣差异，按照最大信息熵原理给出了确定系统分布的熵方法，并运用该方法对前述模型进行了比较.调查数据的验证结果表明，出行分布的信息熵模型可以正确地描述出行分布规律，熵方法可以简单有效地评价不同模型对同一问题描述的优劣差异.本文提出的熵模型和熵方法对城市交通规划具有指导意义.     

GPS组合定位及其改善城市车辆导航性能的意义

由于受到城市中高大建筑的干扰,车辆能接收到的GPS卫星信号数量较少,导致其系统可用性和导航定位精度都比较差。为了改善这一局限,将Galileo卫星信号和GSM网络的BTS站点提供的导航信息与GPS进行组合车辆导航。文章从理论上论述了GPS/Galileo/BTS组合导航模式的可行性,进而分别通过静态和动态2种模式对组合系统在城市定位环境中的可用性和精确性进行了仿真。结果表明GPS/Galileo/BTS组合导航模式能大大改善系统的可用性和精确性。