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61.
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J. M. Carcione 《国际地质力学数值与分析法杂志》1998,22(4):263-275
This work presents a numerical algorithm for solving crack scattering in a transversely isotropic medium whose symmetry axis is perpendicular to the crack surface. The crack is modelled as boundary discontinuities in the displacement u and the particle velocity v, of the stresses [κu+ζv], where the brackets denote discontinuities across the interface. The specific stiffness κ introduces frequency-dependence and phase changes in the interface response and the specific viscosity ζ is related to the energy loss. The numerical method is based on a domain decomposition technique that assignes a different mesh to each side of the interface, that includes the crack plane. As stated above, the effects of the crack on wave propagation are modelled through the boundary conditions, that require a special boundary treatment based on characteristic variables. The algorithm solves the particle velocity–stress wave equations and two additional first-order differential equations (two-dimensional case) in the displacement discontinuity. For each mesh, the spatial derivatives normal to the interface are solved by the Chebyshev method, and the spatial derivatives parallel to the interface are computed with the Fourier method. They allow a highly accurate implementation of the boundary conditions and computation of the spatial derivatives, and an optimal discretization of the model space. Moreover, the algorithm allows general material variability. © 1998 John Wiley & Sons, Ltd. 相似文献
63.
最小二乘配置在钢结构建筑物沉降监测中的应用研究 总被引:1,自引:0,他引:1
根据最小二乘配置可以推估与观测值并无关系的未测点参数特点,文章给出一种钢结构建筑物沉降监测预报新方法,取得了较好的效果.研究结果表明,在建筑物变形监测数据处理中最小二乘配置是一种有效的分析方法. 相似文献
64.
��������ƹ�������С�ⷨ�ĵ�ͼ����任 总被引:1,自引:1,他引:0
????????????????С????????????????????????????????????????????????????ú???????????????в????????????Э???????????????????????????????????????÷???????????任?е????,???????????????????С?????????????????????????С????????? 相似文献
65.
The Karhunen-Loeve (KL) decomposition and the polynomial chaos (PC) expansion are elegant and efficient tools for uncertainty propagation in porous media. Over recent years, KL/PC-based frameworks have successfully been applied in several contributions for the flow problem in the subsurface context. It was also shown, however, that the accurate solution of the transport problem with KL/PC techniques is more challenging. We propose a framework that utilizes KL/PC in combination with sparse Smolyak quadrature for the flow problem only. In a subsequent step, a Lagrangian sampling technique is used for transport. The flow field samples are calculated based on a PC expansion derived from the solutions at relatively few quadrature points. To increase the computational efficiency of the PC-based flow field sampling, a new reduction method is applied. For advection dominated transport scenarios, where a Lagrangian approach is applicable, the proposed PC/Monte Carlo method (PCMCM) is very efficient and avoids accuracy problems that arise when applying KL/PC techniques to both flow and transport. The applicability of PCMCM is demonstrated for transport simulations in multivariate Gaussian log-conductivity fields that are unconditional and conditional on conductivity measurements. 相似文献
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67.
半参数回归与平差模型 总被引:12,自引:5,他引:7
从数据处理几种回归模型出发,对参数、非参数、半参数回归模型进行了讨论,指出了它们的适用前提条件。论证了半参数回归模型的最小二乘核估计与附加系统参数平差、补偿最小二乘准则与最小二乘配置之间的联系与区别,阐述了半参数回归估计在测量平差中的应用前景。 相似文献
68.
利用国际上3个著名的数据分析处理中心CSR、JPL和GSFC给出的3种空间大地测量技术实测的台站运动速度场数据,解算不同空间技术速度场之间的转换参数,即速度场之间的系统差.在扣除两两技术之间速度场的系统差后,用速度场残差计算了空间技术速度场之间的不符值加权中误差作为衡量不同空间技术实测台站速度场的外部检核指标,即外符精度.计算结果表明,VLBI和GPS实测台站地心速度已经达到1 mm/a的精度;SLR实测台站地心速度已经达到2 mm/a的精度. 相似文献
69.
??????????GPS??SLR??VLBI?????????в????н??в???????????????????????????????似??????????????????????????????????????????????SLR??VLBI??????????????????????????????GPS?????????????7 mm ???????????GPS????????????????й?? 相似文献
70.
???????????ζ?????????????????????????????????????С???????÷?????????????????????????????С????????????????????Э?????????????????????麯???????Э????????????????????ó?????Э???????????в????????????Χ??????÷?????????????????????????????б??????????????????????????????Ч??? 相似文献