汉字矢量字形输出的新途径     

孙亚梅  孙以义 《地理学报》1990,45(4):490-497

汉字矢量字形的输出是实现地图图面注记自动化的关键。汉字信息处理可采用用户程序级、操作系统级和硬件级三种方式。一、三两种方式已经过多年的实践,表明都有不尽人意之处。本文从操作系统级出发,将供显示和打印用的点阵式字模转化为适合绘图仪输出的矢量数据。这一方法可利用国标一、二级字库的汉字信息资源,并可以获得地图图面注记所需要的各种字体和字形的汉字。  相似文献   

Constraining Navigation by Matching Swath Bathymetry and Gravity Measurements at Ship Track Crossovers     

Sang-Mook Lee 《Marine Geodesy》2013,36(1):31-53

A method which utilizes the lateral offset information obtained by comparing swath bathymetric data at track crossover points as a further constraint on the navigation is presented. The method, based on generalized least squares inversion theory, derives a new navigational solution that minimizes the overall misfit between the pairs of topography at crossovers while trying to remain smooth and close to the starting model. To achieve a high numerical efficiency during inversions of large matrices, we employed sparse matrix algorithms. The inversion scheme was applied to a set of Sea Beam data collected over the East Pacific Rise near 9° 30' N in early 1988 at the time when the Global Positioning System had limited coverage. The starting model was constructed by taking evenly spaced samples of positions along the tracklines. For each one of the 361 crossovers, we gridded the bathymetric data around the crossover point compared the gridded maps, and calculated the offset and uncertainty associated with this estimation. A suite of inversion solutions were obtained depending on the choice of three free parameters (that is, the a priori model variance, the correlation interval of a priori model, and the trade-off coefficient between fitting the data and remaining close to the a priori model). The best solution was chosen as one that minimizes both the Sea Beam topography and free-air gravity anomaly differences at crossovers. The improvement was significant; the initial rms mismatch between the tracks and free-air gravity anomalies at crossovers was reduced from 610m to 75m and from 2.5mGal to 1.9mGal, respectively.  相似文献   

关于矩阵A~(-1)B的一个注记     

钟尔杰 《地球科学与环境学报》1990,(3)

本文讨论了对求解差分方程有用的矩阵A~(-1)B的范数。胡家赣曾于1983年给出一个关于‖A~(-1)B‖的估计的定理。然而,这里给出一个比原来的证明更为简单的新的证明。  相似文献   

用特征值的差商表示矩阵函数   总被引：1，自引：0，他引：1  

蒋尔雄 《华东地质学院学报》2003,26(2):104-106

设A是一个n×n矩阵,λ1,λ2,……λn是它的特征值,用f(x)在这些特征值上的差商可以得到f(A)。只要f(x)充分光滑,即使有重特征值也可以得到f(A),并且这些重节点差商的计算跟非重节点的一样简单。  相似文献   

一种基于小波分析的旋转不变图像快速匹配方法   总被引：2，自引：1，他引：2  

吴均  朱重光  赵忠明 《遥感学报》2002,6(5):339-342

提出了一种基于小波分解的具有旋转不变特性的三级特征图像快速匹配方法,利用小波分解的高频分量得到图像边缘,进而提取具有旋转不变特性的边缘特征;小波分解的低频分量则用于提取同样具有旋转不变性的图像尺度共生矩阵特征.前一个特征反映了图像边缘间的空间关系,后者则体现了图像灰度间的空间关系,利用这两类特征构成一个三级决策树对图像进行搜索,以查找搜索图中是否包含样本图,对满足匹配条件的若干候选子图,给出具有最大相似特性的一个,实验结果表明,较之于传统的模板匹配方法,该方法具有快速,高精度,抗干扰能力强等优点.  相似文献   

遥感影像分类的归类学习方法     

孙立新  罗高平 《测绘工程》1998,7(3):39-43,49

遥感影像分类专家系统是遥感分类研究中的一个重要发展方向,然而,传统的统计模式识别法和人工神经网络分类法除了能完成具体的影像分类外,不能提供易于被人类理解的分类知识,文中介绍一种基于扩张矩阵的示例学习方法,并将其应用于遥感影像分类知识的自动获取。  相似文献   

L_p模反褶积及其在地震勘探中的应用   总被引：1，自引：0，他引：1       下载免费PDF全文

李凤林  徐伯勋 《地球物理学报》1990,33(5):585-592

在文献[1,2]的基础上,本文提出一种矩阵逆迭代和增强强反射的自适应算法,方法简明,使用方便。理论模拟和实际资料处理结果说明该法是很有效的。  相似文献   

Numerical analysis of ESR spectra from atmospheric samples     

D. Mihelcic  A. Volz-Thomas  H. W. Pätz  D. Kley  M. Mihelcic 《Journal of Atmospheric Chemistry》1990,11(3):271-297

Improvements of the matrix isolation/electron spin resonance technique for the measurement of NO₂, NO₃, and RO₂ radicals in the atmosphere are described. The use of D₂O instead of H₂O as the matrix yields a better spectral resolution and, as a consequence, larger a signal-to-noise ratio as well as better identification of the different species. Reference spectra of the different radicals in H₂O and D₂O matrices are compared. While a large degree of correlation exists amongst the spectra of the different (unsubstituted and substituted) alkylperoxy radicals, the spectra of HO₂, CH₃C(O)O₂, and NO₃ show significant differences that allow their distinction in atmospheric samples.A numerical procedure for the analysis of the composite ESR spectra obtained from atmospheric samples was developed. Subtraction of the dominant NO₂ signal is performed by matching a reference NO₂ spectrum with respect to amplitude, spectral position, and line width to the sample spectrum. The manipulations are performed with the virtually noise-free reference spectrum and are based on physical information. The residual spectrum is then analyzed for RO₂ (and/or NO₃) by simultaneously fitting up to six different reference spectra.The method was applied to laboratory samples as well as to atmospheric samples in order to demonstrate the ability of retrieving small amounts of HO₂ in the presence of large amounts of NO₂ and other peroxy radicals. The new algorithm allowed, for the first time, the identification of the HO₂ and CH₃C(O)O₂ radical in tropospheric air at concentrations ranging up to 40 ppt.  相似文献   

Propagator-matrix Technique for the Viscoelastic Response of a Multi-layered Sphere to Surface Toroidal Traction     

Zdeněk Martinec 《Pure and Applied Geophysics》2007,164(4):663-681

We derive the matrix propagator for the response of a multi-layered, Maxwell viscoelastic sphere to a surface toroidal force in analytical form. Several numerical methods for 2-D and 3-D glacial-isostatic adjustment (GIA) modelling have been applied recently. The present analytical approach may be used as an aid for testing more general algorithms of GIA. The propagator-matrix solution has been tested by comparing it with the analytical solution of two-layer and three-layer spheres, with full agreement obtained.  相似文献   

节点刚度对2008奥运羽毛球热身馆单层网壳稳定性影响研究     

张传成  张宝勤  张爱林 《世界地震工程》2007,23(3):32-40

利用Matrix27单元，对节点半刚性问题进行了APDL二次开发。利用调整节点刚度程序，研究了节点刚度与特征值之间的曲线关系，并重点研究了节点刚度对单层网壳稳定性的影响。通过单层网壳中节点刚度的研究，得到了几点有益的结论，为该类结构的设计提供数据资料和依据。  相似文献