基于IHS和小波变换的遥感图像融合方法研究

基于IHS变换法和小波变换法,提出一种新的图像融合方法．该方法利用IHS变换法增强空间细节表现能力,利用小波变换法保留TM图像的光谱特性,可以最大限度地保留待融合图像的光谱信息,同时可提高待融合图像的清晰度和空间分辨率．     

预应力连续刚构桥梁BIM精细化建模实例

桥梁BIM模型构建技术是运用BIM建模软件建立参数化3D、4D乃至n D桥梁BIM模型,运用信息模型基础数据为桥梁全生命周期服务,为参与桥梁建设各方提供信息化交流平台,为实现建设对象可视化、施工进度控制动态化、信息数据采集智能化提供技术支持。以湖润1号大桥的3D、4D模型构建为例,阐述采用Revit构建大桥模型全过程,提出一种桥梁BIM模型精细化构建的方法与思路。     

轻轨桥梁高墩结构动载试验与振动特性分析

以某城市的跨座式单轨交通桥梁为工程实例,通过对其高墩结构进行振动特性试验,并基于有限元理论对高墩结构进行分析计算。结合实测数据,采用信号处理分析中的方法 FFT变换和HHT变换进行试验结果分析,以此分析高墩结构的振动特性,并对比两种方法的分析结果,发现HHT变换分析方法优于FFT变换。通过实测值与理论值对比分析,发现高墩结构基频实测值高于理论值,表明高墩结构的实际刚度大于理论结果。通过对高墩结构的振动特性进行分析,表明高墩结构动力性能良好,能满足规范及运营要求。     

Estimating the ride quality characteristics of vehicles with random decrement analysis of on-the-road vibration response data

This paper describes the application of a practical analytical technique based on the random decrement method to estimate the rigid sprung mass dynamic characteristics (frequency response function) of road vehicles using only vibration response data during constant-speed operation. A brief history and development of the random decrement technique is presented, along with a summary of work undertaken on optimal parameter selection to establish the random decrement signature. Two approaches to estimate the dynamic characteristics from the random decrement signature are described and evaluated. A custom, single-wheeled vehicle (physical quarter car) was commissioned to undertake a series of on-the-road experiments at various nominally constant operating speeds. The vehicle, also instrumented as an inertial profilometer, simultaneously measured the longitudinal pavement profile to establish the vehicle's actual dynamic characteristics during operation. The main outcome of the paper is that the random decrement technique can be used to provide accurate estimates of the sprung mass mode of the vehicle's dynamic characteristics for both linear and nonlinear suspension systems of an idealised vehicle.     

Walking infrastructure design assessment by continuous space dynamic assignment modeling

For the planning and design of walking infrastructure, characterized by the fact that the pedestrians can choose their paths freely in two‐dimensional space, applicability of traditional discrete network models is limited. This contribution puts forward an approach for user‐optimal dynamic assignment in continuous time and space for analyzing for instance walking infrastructure in a two‐dimensional space. Contrary to network‐based approaches, the theory allows the traffic units to choose from an infinite non‐countable set of paths through the considered space. The approach first determines the continuous paths using a path choice model. Then, origin‐destination flows are assigned and traffic conditions are calculated. The approach to determine a user‐optimal assignment is heuristic and consists of a sequence of all‐or‐nothing assignments. An application example is presented, showing dynamic user equilibrium traffic flows through a realistic transfer station. The example is aimed at illustrating the dynamic aspects of the modeling approach, such as anticipation on expected flow conditions, and predicted behavior upon catching or missing a connection.     

长距离重叠隧道连续下穿平瓦房施工技术

为确保盾构长距离连续下穿古旧平瓦房施工,针对重叠隧道小间距、长距离的施工特点,采取“先下后上、前后错开、支撑加固”的总体施工原则,阐述盾构掘进参数控制、夹层土注浆加固和下线洞内临时支撑台车进行下线隧道加固等关键措施。根据对古旧平瓦房监测、评估结果验证,成功完成了下穿大面积古旧平瓦房的施工,以期为今后采用盾构法施工的重叠隧道长距离、连续下穿古旧平瓦房施工管理提供经验借鉴。     

长昆客运专线涟水特大桥轨道结构设计方案研究

对长昆客运专线涟水特大桥(60+3×100+60)m连续梁上轨道结构进行研究,提出不同轨道结构设计方案,并通过相关调研及计算分析,得出适宜于涟水特大桥上的轨道结构设计方案。采用CRTSⅠ型双块式无砟轨道结构时,需设置钢轨伸缩调节器;若设置钢轨伸缩调节器,将增加工务部门养护维修工作量,应减少钢轨伸缩调节器的设置;采用CRTSⅡ型板式无砟轨道时,可不设置钢轨伸缩调节器。结论:涟水特大桥设计采用CRTSⅡ型板式无砟轨道结构。     

软土深基坑施工配合抢险总结与研究

以佛山地铁3号线美旗站深厚软土基坑工程施工为研究对象,收集和统计施工过程中围护结构变形与支撑内力变化情况,并将统计结果与理论计算值进行对比,分析和总结围护结构受力变形与理论值产生较大差异的原因。针对现场连续墙开裂问题及时进行应急处理,合理调整设计施工方案,实现主体结构顺利封顶,切实有效防止安全事故发生。结合现场施工配合抢险经历,对地铁车站软土深基坑工程围护结构从设计和施工方面提出建议,进一步完善了深厚软土区域地铁地下车站建设技术,推动地铁地下围护结构形式选取合理化,为今后类似地质条件地铁车站深软土基坑工程围护结构方案设计提供一定的借鉴。     

��������С���任��GPS��̬�˲����㷨

针对应用卡尔曼滤波器进行车辆GPS导航信号的动态滤波时难以建立精确的数学模型以及传统小波变换在实时性方面存在不足,提出了基于提升小波变换的GPS动态滤波新算法.该算法采用提升小波变换对车辆GPS导航信号进行分解;用3σ准则和多项式插值方法对各层提升小波变换系数进行粗差探测与数据修复;采用模平方软阈值去噪算法对各层提升小波变换系数进行去噪;最后进行提升小波逆变换,从而实现车辆GPS导航信号的动态滤波。仿真实验结果表明,该算法的导航定位精度优于卡尔曼滤波算法;虽然在导航定位精度方面稍比传统小波变换算法的性能高,但比传统小波变换算法速度快一倍;显然该算法对车辆GPS导航系统是有效的.     

金沙大桥扩建改造工程总体设计

金沙大桥扩建改造工程为原有老桥两侧各新建一幅桥梁;介绍了该桥的总体布置、结构设计等,特别是引桥跨大堤处采用路堤结合方案成为该工程一大亮点,有关经验可供类似工程参考。