高速公路路基沉降预测的神经网络模型

软土地基的沉降控制是保证高速公路建设质量的一个关键技术.论文主要介绍了一个对高速公路路基沉降进行预测的神经网络模型.对神经网络的BP算法进行了改进,提高了BP算法的学习收敛速度和网络性能的稳定性.神经网络法预测路基沉降的难点之一是合适的训练样本构造问题,论文提出了新颖独特的“训练样本”构造方法,且应用效果良好.利用路基沉降量实测资料直接建模,采用BP网络计算的改进算法,可较为准确地预测大约4个月之后的沉降量,预测值与实测值吻合较好.     

基于ArcGIS Flex API的城市路网管理系统的设计与实现

提出了一种新型基于ArcGIS Flex API技术的WebGIS系统,相比传统WebGIS系统,它具有更丰富的表现力,交互能力更强,用户体验更好。系统成功实现了空间查询与定位、数据统计、绘制量算、地图打印输出等功能,旨在能给城市规划和交通规划部门提供一个良好的管理规划和决策支持的WebGIS共享平台。     

浅谈客运专线CPⅢ建网与施测技术

结合西安至宝鸡客运专线XBZQ-2标段施工实践,主要介绍了客运专线CPⅢ建网与施测的技术,实践结果表明工程所采用的CPⅢ施测技术具有精度高、安全可靠等优点,对类似工程具有一定的参考价值。     

鲲鹏山变形监测方案设计

通过论述变形监测控制网的建立与优化、变形监测点的布设、变形监测与数据处理的方法,给出了一套比较完整的鲲鹏山变形监测方案。     

基于UCD+POS的1∶10000成图像控网布设方案的试验与研究

2012年辽宁省测绘地理信息局将利用UCD+POS AV 510资料进行约30 000 km2的1∶10 000基本地形图更新。本文从用户的角度,以GeolordAT空三加密软件平台为基础,详细阐述了针对UCD+POS数据,进行资料分析、数据处理、空三加密的步骤、方法、精度和注意事项等,并得出切实可行的像控网布设方案。     

基于CORS系统的网络RTK技术在城镇地籍测量中的应用

介绍了CORS的基本原理及基本结构,通过实例分析了基于CORS系统的网络RTK技术在地籍测绘生产中的优势,研究了基于CORS系统的网络RTK定位精度的评定方法。结果表明,利用基于CORS系统的网络RTK技术进行测绘生产的方法科学、精度可靠。证明了基于CORS系统的网络RTK技术在测绘生产中具有广阔的应用前景。     

“GALICIA'S HURRICANE”: ACTOR NETWORKS AND ICONIC CONSTRUCTIONS*

Monumental constructions are created for a purpose, often as a symbolic representation of a particular vision of a people or a place. Spain's Cidade da Cultura, a museum conceptualized by Galicia's former president with the hubristic goal of creating a world icon, is one such example. Like many iconic constructions, the Cidade da Cultura project was highly contentious and sparked a regionwide political debate, vastly overran its projected cost, and years later remains controversial and incomplete. An actor‐network theory analysis of why the project failed reveals the different roles played by individual components in the vast network of actors, including the monument itself, which came to exercise influence over the outcome of the project. Because the former president could not fully control this expanding network of actors, events soon spun out of control in what became popularly known as “Galicia's Hurricane.”     

植被发育斜坡非饱和带大孔隙

在气候温湿的滑坡灾害易发区,根系通道、动物通道、干裂缝、管道及团聚体间的结构性孔隙等大孔隙普遍存在于斜坡非饱和带中.采用微观观察、化学分析和现场试验方法并结合相关学科的研究成果,分析大孔隙界定、大孔隙类型和主控因素、大孔隙三维空间结构及大孔隙时效稳定.不同测量方法的差异和大孔隙密度时空变异性是目前大孔隙定义缺乏统一性的原因.大孔隙尺寸不能作为唯一标准界定大孔隙,必须考虑其三维几何形态.多因素控制大孔隙的成因和类型,其中根系通道、裂缝和结构性孔隙对优先流有显著贡献.需从三维几何学和拓扑学方面进一步研究大孔隙三维结构.枯枝落叶层是大孔隙抵御环境因素扰动的重要屏障,但大孔隙域与周围基质域水量交换对大孔隙时效稳定是不利的.深入研究以上问题对植被发育斜坡优先流模型的改进和发展是重要的.     

基于不同DEM数据源的数字河网提取对比分析——以韩江流域为例

基于HYDRO1K、SRTM3和ASTER GDEM三种DEM数据,利用BTOPMC地形子模型提取韩江流域河网,并作对比分析。结果表明:①SRTM3提取的河网精度最高,HYDRO1K相对最低。②DEM的垂直精度对提取的河网精度起控制作用。ASTER GDEM的水平分辨率较高,但垂直精度不如SRTM3,因而提取的河网精度不如SRTM3。③HYDRO1K提取大尺度流域河网具有一定的精度,但在地势平坦区域的效果较差,HY-DRO1K不宜用来提取小尺度流域河网。④由DEM提取的数字河网精度与当地的地面坡度以及处理DEM的填洼算法有关。     

On different types of adjustment usable to calculate the parameters of the stream power law

Model parameterization through adjustment to field data is a crucial step in the modeling and the understanding of the drainage network response to tectonic or climatic perturbations. Using as a test case a data set of 18 knickpoints that materialize the migration of a 0.7-Ma-old erosion wave in the Ourthe catchment of northern Ardennes (western Europe), we explore the impact of various data fitting on the calibration of the stream power model of river incision, from which a simple knickpoint celerity equation is derived. Our results show that statistical least squares adjustments (or misfit functions) based either on the stream-wise distances between observed and modeled knickpoint positions at time t or on differences between observed and modeled time at the actual knickpoint locations yield significantly different values for the m and K parameters of the model. As there is no physical reason to prefer one of these approaches, an intermediate least-rectangles adjustment might at first glance appear as the best compromise. However, the statistics of the analysis of 200 sets of synthetic knickpoints generated in the Ourthe catchment indicate that the time-based adjustment is the most capable of getting close to the true parameter values. Moreover, this fitting method leads in all cases to an m value lower than that obtained from the classical distance adjustment (for example, 0.75 against 0.86 for the real case of the Ourthe catchment), corresponding to an increase in the non-linear character of the dependence of knickpoint celerity on discharge.