地形校正中央区求积公式     

边少锋  刘长剑 《测绘学院学报》1996,(1)

利用非奇变换首先将地形校正奇异积分非奇异，其次利用ＮｅｗｔｏｎＣｏｔｅｓ积分，本文推导了几组适用于地形校正中央区积分的求积公式。  相似文献   

自然降雨量与水稻产量的关系          下载免费PDF全文

李玉林 《气象》1997,23(2):38-40

利用旬雨量与历史同期产量资料，使用积分回归和多元回归等方法，分析自然降雨量与水稻产量的关系，以证实人工增雨对水稻产量提高所起的作用。结果表明，全省早稻亩产量随旬雨量增加平均为０．１６４ｋｇ／ｍｍ，晚稻亩产量增加平均为０．１１ｋｇ／ｍｍ。  相似文献   

The numerical method of Fourier eigen transform and its application in seismicity analysis     

陈兵  郑治真  江在森 《地震学报(英文版)》1997,10(6):753-759

ＴｈｅｎｕｍｅｒｉｃａｌｍｅｔｈｏｄｏｆＦｏｕｒｉｅｒｅｉｇｅｎｔｒａｎｓｆｏｒｍａｎｄｉｔｓａｐｐｌｉｃａｔｉｏｎｉｎｓｅｉｓｍｉｃｉｔｙａｎａｌｙｓｉｓＢＩＮＧＣＨＥＮ１）（陈兵）ＺＨＩ－ＺＨＥＮＺＨＥＮＧ２）（郑治真）ＺＡＩ－ＳＥＮＪＩＡＮＧ...  相似文献   

Spatial continuity measures for probabilistic and deterministic geostatistics   总被引：3，自引：0，他引：3  

E. H. Isaaks  R. Mohan Srivastava 《Mathematical Geology》1988,20(4):313-341

Geostatistics has traditionally used a probabilistic framework, one in which expected values or ensemble averages are of primary importance. The less familiar deterministic framework views geostatistical problems in terms of spatial integrals. This paper outlines the two frameworks and examines the issue of which spatial continuity measure, the covarianceC (h) or the variogram (h), is appropriate for each framework. AlthoughC (h) and (h) were defined originally in terms of spatial integrals, the convenience of probabilistic notation made the expected value definitions more common. These now classical expected value definitions entail a linear relationship betweenC (h) and (h); the spatial integral definitions do not. In a probabilistic framework, where available sample information is extrapolated to domains other than the one which was sampled, the expected value definitions are appropriate; furthermore, within a probabilistic framework, reasons exist for preferring the variogram to the covariance function. In a deterministic framework, where available sample information is interpolated within the same domain, the spatial integral definitions are appropriate and no reasons are known for preferring the variogram. A case study on a Wiener-Levy process demonstrates differences between the two frameworks and shows that, for most estimation problems, the deterministic viewpoint is more appropriate. Several case studies on real data sets reveal that the sample covariance function reflects the character of spatial continuity better than the sample variogram. From both theoretical and practical considerations, clearly for most geostatistical problems, direct estimation of the covariance is better than the traditional variogram approach.This paper was presented at MGUS 87 Conference, Redwood City, California, 14 April 1987.  相似文献   

并矢格林函数等效源法在钻孔电磁波法中的应用     

Li Chunxiang Chen Zhen Li Shouchun 《吉林大学学报(地球科学版)》1989,(4)

针对双孔电波法的实际情况,研究无限有耗媒质中,在半波偶极天线激励下,存在导电异常体的散射问题。理论上是根据等效源定理在散射体内引入等效电流,利用并失格林函数建立电场的积分方程并将其化为矩阵方程。在数值计算中,精心设计计算机程序,为提高计算精度,采取小圆柱体作为剖分单元。从物理角度对积分方程奇异点做巧妙的处理。经多次试算,结果令人满意。从而证明本文提出的理论和计算方法的有效性和适用性。  相似文献   

A solution to the downward continuation effect on the geoid determined by Stokes' formula   总被引：2，自引：1，他引：2  

L.E. Sjöberg 《Journal of Geodesy》2003,77(1-2):94-100

 The analytical continuation of the surface gravity anomaly to sea level is a necessary correction in the application of Stokes' formula for geoid estimation. This process is frequently performed by the inversion of Poisson's integral formula for a sphere. Unfortunately, this integral equation corresponds to an improperly posed problem, and the solution is both numerically unstable, unless it is well smoothed, and tedious to compute. A solution that avoids the intermediate step of downward continuation of the gravity anomaly is presented. Instead the effect on the geoid as provided by Stokes' formula is studied directly. The practical solution is partly presented in terms of a truncated Taylor series and partly as a truncated series of spherical harmonics. Some simple numerical estimates show that the solution mostly meets the requests of a 1-cm geoid model, but the truncation error of the far zone must be studied more precisely for high altitudes of the computation point. In addition, it should be emphasized that the derived solution is more computer efficient than the detour by Poisson's integral. Received: 6 February 2002 / Accepted: 18 November 2002 Acknowledgements. Jonas ?gren carried out the numerical calculations and gave some critical and constructive remarks on a draft version of the paper. This support is cordially acknowledged. Also, the thorough work performed by one unknown reviewer is very much appreciated.  相似文献   

The BDS statistic and residual test     

H. S. Kim  D. S. Kang  J. H. Kim 《Stochastic Environmental Research and Risk Assessment (SERRA)》2003,17(1-2):104-115

 The conventional nonparametric tests have been widely used in many fields for the residual analysis of a fitted model on observations. Also, in recent, a new technique called the BDS (Brock–Dechert–Scheinkman) statistic has been shown that it can be used as a powerful tool for the residual analysis, especially, of a nonlinear system. The purpose of this study is to compare the powers of the nonparametric tests and BDS statistic by residual analysis of the fitted models. This study evaluates stochastic models for four monthly rainfalls in Korea through the residual analysis by using the conventional nonparametric and BDS statistics. We use SARIMA and AR Error models for fitting each rainfall and perform the residual analysis by using the test techniques. As a result, we find that the BDS statistic is more reasonable than the conventional nonparametric tests for the residual analysis and AR Error model may be more appropriate than SARIMA model for modeling of monthly rainfalls. This work was supported by grant No. R01-2001-000-00474-0 from the Basic Research Program of the Korea Science & Engineering Foundation.  相似文献   

轨道交通中线测设统一数学模型的建立   总被引：4，自引：0，他引：4  

吴浩  花向红  王新洲  周庆俊 《武汉大学学报(信息科学版)》2002,27(5):478-482

根据对常用的两种中线测设数学模型的分析，从线路中线曲率半径的特点出发，提出了中线整体积分数学模型，并导出其计算公式。为了实现整体积分模型的计算，对龙贝格积分算法进行了改进，并用于武汉市轨道交通一号线一期工程的中线测设。比较和分析表明，从实用性和精度等方面来说，整体积分模型是目前轨道交通最优的中线测设模型。  相似文献   

Seismogram synthesis for piecewise heterogeneous media   总被引：4，自引：0，他引：4  

Li-Yun Fu 《Geophysical Journal International》2002,150(3):800-808

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The axisymmetric consolidation of a semi‐infinite transversely isotropic saturated soil     

S. L. Chen  L. Z. Chen  L. M. Zhang 《国际地质力学数值与分析法杂志》2005,29(13):1249-1270

This paper presents an exact analytical solution to fully coupled axisymmetric consolidation of a semi‐infinite, transversely isotropic saturated soil subjected to a uniform circular loading at the ground surface. The analysis is under the framework of Biot's general theory of consolidation. First, the governing equations of consolidation are transformed into a set of equivalent partial differential equations with the introduction of two auxiliary variables. These partial differential equations are then solved using Hankel–Laplace integral transforms. Once solutions in the transformed domain have been obtained, the actual solutions in the physical domain for displacements and stress components of the solid matrix, pore‐water pressure and fluid discharge can be finally obtained by direct numerical inversion. The accuracy of the numerical solutions developed is confirmed by comparison with an existing exact solution for an isotropic and saturated soil that is a special case of the more general problem addressed. Numerical analyses are also presented to investigate the influence of the degree of material anisotropy on the consolidation settlement. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献