直流电阻率最小二乘间歇反演     

刘海飞  阮百尧  吕玉增 《物探化探计算技术》2007,29(4):339-341

为了解地下介质物理特性随时间的变化,采用地球物理监测数据的成像方法已经逐渐得到应用。一种常用的途径就是通过独立反演不同时刻采集的地球物理数据,来重构间歇影像,这使得实测的数据信息得不到充分利用。因此,这里提出了一种同时反演所有不同时刻观测数据的新方法,即通过一次反演过程来获得所有不同时刻的地下模型。在反演过程中,通过引入时间和空间正则化因子来改善反演的稳定性,减少反演的多解性。最后,以直流电阻率监测数据反演为例,验证所提算法的有效性。  相似文献   

地面核磁共振正则化反演方法研究   总被引：2，自引：1，他引：1  

张文权  翁爱华 《吉林大学学报(地球科学版)》2007,37(4):809-813

不同的模型约束对基于正则化反演技术的地面核磁共振测深数据反演影响很大。利用理论数据讨论了平坦模型和光滑模型约束及与之相关的正则化参数对反演结果的影响规律。模拟表明,无论是高信噪比数据,还是低信噪比数据,反演的含水量在小正则化参数时,对模型约束的依赖性不大,主要受正则化参数影响。大正则化参数时反演分辨率低,而小正则化参数在保证数据拟合精度提高的同时,增加了模型的分辨率,能获得更可靠的含水量分布。  相似文献   

Classification of Motions for Generalization of the two Centers Problem on a Sphere     

T. G. Vozmischeva 《Celestial Mechanics and Dynamical Astronomy》2000,77(1):37-48

The generalization of a test particle motion in a central field of two immovable point-like centers to the case of a constant curvature space, on a three-dimensional sphere, is investigated in the paper. The bifurcation set in the plane of integrals of motion is constructed and the classification of the domains of possible motion is carried out on a two-dimensional sphere. The regularization of the Kepler’s problem on a two-dimensional sphere is carried out. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

非饱和土中溶质迁移参数反演的HISR方法   总被引：1，自引：0，他引：1  

崔凯李兴斯  李宝元 《地球科学》2004,29(2):247-252

以非饱和土中溶质迁移参数反演问题为背景, 依据正则化方法的思路, 以Itakura Saito距离作为同伦函数中的平凡问题, 将同伦方法引入非线性参数反演问题的求解, 进而提出一种求解非线性参数反演问题的大范围收敛(HomotoyItakura SaitoRegularization, HISR) 方法.为保证迭代稳定性, 并同时削弱观测噪声的影响, 同伦参数的修正采用了连续化修正方法.本文将HISR方法应用于求解带有平衡及非平衡吸附效应的一维非饱和土中溶质迁移参数反演问题, 计算结果表明HISR方法具有大范围收敛性及计算稳健性, 同时有较强的抵抗观测噪声的能力.   相似文献   

用Landweber法求解GPS定位参数   总被引：1，自引：0，他引：1  

冯遵德  李云云 《测绘科学》2011,36(6):144-145

在GPS定位中,由于观测结构不好等原因存在病态问题,常常造成GPS定位参数的最小二乘解不稳定.针对求解病态可题在参数估计中的影响,本文提出采用Landweber迭代正则化求解整周模糊度;在实施过程中,提出了迭代次数的确定方法;根据计算实例验证了Landweber迭代正则化方法求解GPS定位参数的有效性.  相似文献   

Global chaoticity in the Pythagorean three-body problem     

S. J. Aarseth  J. P. Anosova  V. V. Orlov  V. G. Szebehely 《Celestial Mechanics and Dynamical Astronomy》1994,58(1):1-16

The effects of small changes in the initial conditions of the Pythagorean three-body problem are investigated by computer simulations. This problem consists of three interacting bodies with masses 3, 4 and 5 placed with zero velocities at the apices of a triangle with sides 3, 4 and 5. The final outcome of this motion is that two bodies form a binary and the third body escapes. We attempt to establish regions of the initial positions which give regular and chaotic motions. The vicinity of a small neighbourhood around the standard initial position of each body defines a regular region. Other regular regions also exist. Inside these regions the parameters of the triple systems describing the final outcome change continuously with the initial positions. Outside the regular regions the variations of the parameters are abrupt when the initial conditions change smoothly. Escape takes place after a close triple approach which is very sensitive to the initial conditions. Time-reversed solutions are employed to ensure reliable numerical results and distinguish between predictable and non-predictable motions. Close triple approaches often result in non-predictability, even when using regularization; this introduces fundamental difficulties in establishing chaotic regions.  相似文献   

Global Regularization of the Restricted Problem of Three Bodies     

Bálint Érdi 《Celestial Mechanics and Dynamical Astronomy》2004,90(1-2):35-42

The global regularizing transformations of the planar, circular restricted problem of three bodies are studied. It is shown that all these transformations can be written in the same general form which is the solution of a first order ordinary differential equation. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

不适定方程正则化算法的谱分解式   总被引：14，自引：3，他引：11  

沈云中  许厚泽 《大地测量与地球动力学》2002,22(3):10-14

从观测方程系数矩阵的谱分解着手探讨不适宜方程的正则化算法。利用谱分解式阐明了正则化的主要作用是平滑对参数估值比较敏感的观测误差的高频分量，完整给出了最小二乘平差、秩亏平差和病态方程正则化解的谱分解公式，证明了正则化解参数估值偏离真值的二次范数的期望值与均方误差是等价的。  相似文献   

The planar Hill problem with oblate primary     

K.E. Papadakis 《Astrophysics and Space Science》2004,293(3):271-287

The regularized equations of motion of the planar Hill problem which includes the effect of the oblateness of the larger primary body, is presented. Using the Levi-Civita coordinate transformation as well as the corresponding time transformation, we obtain a simple regularized polynomial Hamiltonian of the dynamical system that corresponds to that of two uncoupled harmonic oscillators perturbed by polynomial terms. The relations between the synodic and regularized variables are also given. The convenient numerical computations of the regularized equations of motion, allow derivation of a map of the group of families of simple-periodic orbits, free of collision cases, of both the classical and the Hill problem with oblateness. The horizontal stability of the families is calculated and we determine series of horizontally critical symmetric periodic orbits of the basic families g and g'. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Quaternions and the perturbed Kepler problem     

Jörg Waldvogel 《Celestial Mechanics and Dynamical Astronomy》2006,95(1-4):201-212

Quaternions, introduced by Hamilton (Philos. Mag. 25, 489–495, 1844) as a generalization of complex numbers, lead to a remarkably simple representation of the perturbed three-dimensional Kepler problem as a perturbed harmonic oscillator. The paper gives an overview of this technique, including an outlook to applications in perturbation theories.  相似文献