基于GPS的列控轨道地图数据生成方法研究     

刘江  蔡伯根  唐涛  王剑 《测绘学报》2011,40(1):111-117

为满足列车运行控制及列车定位不同层次的需求,将轨道地图数据分为轨道专用数据、轨道线路数据及地形环境数据,并对轨道地图线路数据按照不同尺度划分为特征点层及插值点层,形成列控轨道地图结构.针对原始GPS地图测量数据,采用多点加权距离检验及Kalman估计差值检验实现错误数据剔除;根据轨道曲线特征对原始数据进行划分,通过在各...  相似文献   

基于非下采样Contourlet变换的极化SAR图像融合与去噪     

孙晓霞  张继贤  燕琴 《测绘科学》2011,36(3):70-72

针对非下采样Contourlet变换(NSCT)在处理噪声影像中具有的优势,以及同极化SAR图像(HH、VV)之间的相关性与互补性,本文实验了一种基于非下采样Contourlet变换的极化图像融合方法。该方法首先对每个极化图像进行多尺度、多方向分解,然后对不同分解子带系数分别采用有利于斑点噪声去除和信息增强的融合规则进行融合,最终通过NSCT反变换得到融合图像。通过信息熵、相关系数以及等效视数等指标的评价,验证了该方法可以有效地实现信息增强,同时该方法也在一定程度上降低了斑点噪声的负面影响。  相似文献   

中国实施铁路电气化的节能减排量估算   总被引：1，自引：0，他引：1       下载免费PDF全文

何吉成  吴文化 《气候变化研究进展》2011,7(1):29-34

基于中国铁路部门逐年统计数据,计算了1975-2007年中国电气化铁路带来的逐年节能量和CO2、烟尘、SO2、CO、NOx与CnHm的直接减排量,并分析了其变化特点.结果表明,33年来电气化铁路使得中国铁路运输行业年均节省123.0万t标准煤的能源消耗,节能量年均增长13.9万t标准煤;CO2、烟尘、SO2、CO、NO...  相似文献   

三维全景虚拟地震台站的建立     

檀玉娟  李盛乐 《华南地震》2011,31(3):78-82

三维全景是一种基于静态图像的真实场景虚拟现实技术,首先简要叙述该技术的主要原理和技术路线,基于此建立了可以在网络上发布和浏览的三维全景虚拟地震台站系统,该技术丰富了防震减灾宣传工作的手段和内容.  相似文献   

Predicting size effect on diffusion-limited current density of oxygen reduction by copper wire     

芦永红  徐海波  王佳  钟莲 《中国海洋湖沼学报》2011,29(1)

The size effect of copper wire radius (0.04–0.82 mm) on the diffusion-limited current density of an oxygen reduction reaction in stagnant simulated seawater (naturally aerated 0.5 mol/L NaCl) is investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) and compared with the results obtained in 0.5 mol/L H2SO4. In the oxygen diffusion-limited range, size effect is found to occur independent of electrolytes, which is attributed to non-linear diffusion. Additionally, to sati...  相似文献   

安徽淮河流域洪涝灾害防灾减灾能力评估   总被引：13，自引：3，他引：10  

黄大鹏  郑伟  张人禾  霍治国  李加林  彭顺风 《地理研究》2011,30(3):523-530

采用层次分析法并融合专家意见,遵循客观性、数据获取便利性、指标量化可行性并突出主导因素等原则,构建综合防洪除涝能力、监测预警能力、抢险救灾与恢复重建能力以及灾害管理能力的洪涝灾害防灾减灾能力综合评估指标体系,对安徽淮河流域各县市洪涝灾害防灾减灾能力进行评估.评估表明:蚌埠市防灾减灾能力最高,其次为难南市、淮北市,再次为...  相似文献   

地球层析成像在减轻灾害中的作用     

郭履灿  赵静 《CT理论与应用研究》2004,13(2):60-63

目的说明地球层析成像一词的含义和它所包括的分支有:地震层析,电阻率层析,大地电磁层析,磁共振成像, 地震破裂面照相以及探地雷达成像等.概括当前这几种手段的成就,所能达到的成像精密度, 用现代的计算方法、反演地下介质速度、衰减Q值、密度、孔隙度分布、介质破裂程度,可提高震源定位精度,再借鉴医学上检测癌细胞发生、发展过程的模式,建立相应的预测模式.判断未来破坏性地震的孕震结构,发展趋势,以及地下水与电阻率图像随季节变化的关系.初步阐明地球层析成像在减轻地震灾害、洪水灾害与火山喷发灾害中的作用.将地电阻率层析与磁共振测深成像相结合应用于探测地下水的一些基本分布特征,判定潜伏断层的特征,追踪电阻率异常区其附近的电性精细结构,分辨率可以达到1米左右.结合起来可探测地下裂隙分布,发现活断层,对高层建筑物(80米以上)和大型桥梁、水坝、堤防的安全性评价具有重要作用,以便及早加固,以减轻损失;结论利用上述地球层析成像的几种手段,可以探测地下活动断层、孕震结构和地下水与电阻率随季节的变动,为判定高楼和堤坝的安全性提供依据,在减轻灾害中发挥日益重要的作用.  相似文献   

基于GIS的泸水县易地扶贫搬迁安置地选择     

李益敏 《测绘软科学研究》2010,(3):59-63

易地扶贫搬迁是对生活在恶劣环境中的贫困人口采取的扶贫举措。泸水县尚有大量人口需要易地搬迁解决贫困问题,泸水县特殊的峡谷地理环境,使安置地的选择成为棘手的问题。将GIS技术应用于扶贫易地搬迁地选择中,可以方便地找出适宜的搬迁居住地,为当地政府易地安置提供决策参考依据。安置区的选择,主要考虑以下因子：交通便利、土地资源丰富、水源丰富、坡度较为平缓、海拔较低,避开地质灾害隐患点和自然保护区等。通过GIS技术,将上述因子图层叠加后找到适合的安置地。结果表明：泸水县难以找到成片的面积较大的安置区,安置区呈零星状分布在各个乡镇。  相似文献   

Effect of connecting rain barrels on the storage size reduction     

Yongwon Seo  Nam‐Jeong Choi  Daeryong Park 《水文研究》2012,26(23):3538-3551

In this article, the possibility of sharing rain barrels and the potential benefit of reducing storage size through physical and non‐physical connections of rain barrels in a community are investigated. Using the concepts of homogeneous/heterogeneous users in rainwater harvesting systems (RWHS), two simple cases of a community composed of four prospective users are examined. The first is performed with the users who have the same mean and variance in water demands (homogeneous users), and the second is with the users with different means and variances (heterogeneous users). To take account for the rainfall characteristics in different places, historical records from six cities in the USA are used for storage–reliability–yield analysis. The result indicates that required total storage can be reduced by connecting multiple rain barrels. In addition, a significant difference is found between homogeneous and heterogeneous user groups. Homogeneous users do not achieve a substantial benefit from connecting their rain barrels; these users may even be disadvantaged by sharing. In contrast, heterogeneous users receive benefit by reducing the total required storage. Most benefit is expected between users with maximum difference in mean water demands. The reduction in storage size was as considerable as 37% in this study. The quantity of storage reduction depends on locations and target reliabilities. Knowledge of the benefits and limitations of rain barrel connections can improve RWHS performance through ability to customize a network plan for individual users. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Preconditioned IDR(s) iterative solver for non‐symmetric linear system associated with FEM analysis of shallow foundation     

H.H.T. Tran  K.C. Toh  K.K. Phoon 《国际地质力学数值与分析法杂志》2013,37(17):2972-2986

Non‐associated flow rule is essential when the popular Mohr–Coulomb model is used to model nonlinear behavior of soil. The global tangent stiffness matrix in nonlinear finite element analysis becomes non‐symmetric when this non‐associated flow rule is applied. Efficient solution of this large‐scale non‐symmetric linear system is of practical importance. The standard Krylov solver for a non‐symmetric solver is Bi‐CGSTAB. The Induced Dimension Reduction [IDR(s)] solver was proposed in the scientific computing literature relatively recently. Numerical studies of a drained strip footing problem on homogenous soil layer show that IDR(s = 6) is more efficient than Bi‐CGSTAB when the preconditioner is the incomplete factorization with zero fill‐in of global stiffness matrix K_ep (ILU(0)‐K_ep). Iteration time is reduced by 40% by using IDR(s = 6) with ILU(0)‐K_ep. To further reduce computational cost, the global stiffness matrix K_ep is divided into two parts. The first part is the linear elastic stiffness matrix K_e, which is formed only once at the beginning of solution step. The second part is a low‐rank matrix Δ, which is re‐formed at each Newton–Raphson iteration. Numerical studies show that IDR(s = 6) with this ILU(0)‐K_e preconditioner is more time effective than IDR(s = 6) with ILU(0)‐K_ep when the percentage of yielded Gauss points in the mesh is less than 15%. The total computation time is reduced by 60% when all the recommended optimizing methods are used. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献