GPS测量中多路径效应的研究

全面论述了GPS测量中多路径效应产生的原理 ,并简要介绍了近几年国内外减弱和消除多路径效应的方法及手段。     

Learning tracking controllers under unknown disturbances for the installation of rigid and flexible structures

During the installation operations of underwater structures, offshore structures such as semisubmersibles, the steady nonlinear hydrodynamic force due to the ocean current, the tidal current, and the hydrodynamic interaction between structures are regarded as major disturbances. Generally, it is difficult and very expensive to collect information about these disturbances in advance, although such knowledge would be important and necessary for precise installation. Because of this situation, we have proposed a learning tracking controller (LTC) for automated tracking/docking operations of offshore structures. The LTC can be operated without any information about current, and can be applied to the installation problem of flexible structures whose flexibility cannot be ignored. In order to confirm the effectiveness of the LTC, basin tests were carried out using experimental models with an unknown current. Two types of basin experiment were executed using an ultrasound ranging system and thrusters. One was trajectory tracking of a semisubmersible, and the other was the precise mating of flexible underwater structures. In both cases the LTC showed good performance, and in the latter case in particular, two flexible models were successfully made to track the given trajectory and dock to the docking targets with an accuracy of ±5 mm, after the trajectory had been tracked six to seven times for learning purposes. No elastic responses were excited in the flexible model. Received for publication on Dec. 1, 1999; accepted on March 13, 2000     

Efficient solution algorithm for finding spatially dependent reliable shortest path in road networks

Travel times are generally stochastic and spatially correlated in congested road networks. However, very few existing route guidance systems (RGS) can provide reliable guidance services to aid travellers planning their trips with taking account explicitly travel time reliability constraint. This study aims to develop such a RGS with particular consideration of travellers' concern on travel time reliability in congested road networks with uncertainty. In this study, the spatially dependent reliable shortest path problem (SD‐RSPP) is formulated as a multi‐criteria shortest path‐finding problem in road networks with correlated link travel times. Three effective dominance conditions are established for links with different levels of travel time correlations. An efficient algorithm is proposed to solve SD‐RSPP by adaptively using three established dominance conditions. The complexities of road networks in reality are also explicitly considered. To demonstrate the applicability of proposed algorithm, a comprehensive case study is carried out in Hong Kong. The results of case study show that the proposed solution algorithm is robust to take account of travellers' multiple routing criteria. Computational results demonstrate that the proposed solution algorithm can determine the reliable shortest path on real‐time basis for large‐scale road networks. Copyright © 2016 John Wiley & Sons, Ltd.     

广州地铁3号线VCC故障情况下的行车组织方案

介绍了基于环线通信,由VCC（车辆控制中心）系统控制的移动闭塞信号设计思想,分析该思想下的追踪原理,并着重以广州地铁3号线为现有条件,重点阐述了VCC故障情况下的行车组织方案,并分析了此种情况下的线路通过能力。     

天津地铁1号线南延伸方案研究

从城市区域规划建设、道路修建、轨道交通线网的合理性、客流流向等方面论述与分析地铁1号线南延伸的必要性,对延伸线路的接轨点、线路走向进行方案比选。推荐天津地铁1号线南延伸项目自双林站站前约500 m区间接轨引出,基本沿海河中游规划路由、敷设,终点站设在靠近汉港快速附近,与C1、C2、C4、Z1、Z3轨道交通线沟通与换乘。     

基于轨道交通网络特点的K最短路算法研究

城市轨道交通网络发展带来出行路径选择的复杂性,为了科学掌握线路客流,组织运输,合理引导乘客路径选择,需要开展轨道多路径算法研究;同时,随着生活节奏加快,要求算法高效,注重路径获取的实时性。针对轨道网络特征,将站点之间K最短路搜索转化为线路换乘组合搜索,降低搜索空间复杂度,并利用杭州轨道交通网络进行案例验证。算法明显提升轨道网络K最短路搜索效率,能够更快速响应轨道交通实际运行变化,有助于提升今后轨道交通出行服务应用。     

基于CBTC的灯泡线线路拓扑结构分析与设计

分析灯泡线对既有CBTC系统线路拓扑结构下链接关系的影响,提供一种基于轨道交通灯泡线线路的系统设计方法,并给出描述线路拓扑的数据结构定义。系统设计方法核心思想是:在CBTC系统中,将灯泡线中的拐点作为一个链接对象。通过对拐点两侧的区段链接关系进行描述和确定,对于存在灯泡线的线路,根据列车运行方向,实现对含拐点线路的路径搜索,并对包络跨在拐点上的列车进行包络位置计算,对列车运行方向与信号机、车档等方向的一致性判断给出具体方法。通过使用这种方法,使得既有CBTC系统少量修改拓扑结构,就能支持灯泡线线路。     

基于离散元理论的粗粒土三轴试验细观模拟

基于三维离散元颗粒流理论,综合考虑颗粒间黏结力,确定颗粒接触本构关系,建立有黏结材料工程性质的数值仿真模型,实现对粗粒土工程力学特性的模拟。根据某粗粒土室内三轴试验结果和大量数值试验,对颗粒流数值模型进行标定,精确再现室内试验的加载曲线。基于标定后的颗粒流模型,针对不同的试样加载过程,分析不同应力路径下的力学响应。通过对颗粒流试样细观参数的进一步分析,研究试样的颗粒间的摩擦系数、细观连接强度以及孔隙率对宏观力学特性的影响。揭示模型细观参数对宏观力学响应的影响,研究结果表明：通过控制细观参数可实现对宏观力学响应的调整,并据此给出细观参数选取的若干建议,为今后的颗粒流模拟试验提供参考。     

阴影遮挡下组串式MPPT应用研究

以光伏组件BP4170为研究对象,基于Matlab建立了仿真模型,分析了光伏组串、光伏阵列在阴影遮挡下的输出特性,对集中式MPPT（最大功率点跟踪）和组串式MPPT的输出功率进行了评估和对比,并通过计算和分析得到组串式MPPT技术的适用范围,为光伏发电系统的设计提供了理论依据。