一类非线性奇异边值问题的解的存在性     

杨博  张炳根 《中国海洋大学学报(自然科学版)》1995,(1)

本文研究了如下的高阶奇异边值问题解的存在性ｙ（ｎ）＋ｆ（ｔ，ｙ，ｙ＇，．．．，ｙ（ｎ－２））＝０，ｎ≥２，０＜ｔ＜１，ｙ（ｉ）（０）＝０，０≤ｉ≤＜ｎ－２，ｙ（ｎ－１）（１）＝０其中，ｆ（ｔ，ｙ１，．．．，ｙｍ－１）在ｙｉ＝０处有奇性，ｉ＝１，．．．，ｎ－１。我们给出了该问题解存在的一个新的充分条件  相似文献   

单站地基GPS天顶延迟反演大气剖面研究   总被引：1，自引：0，他引：1  

林乐科  赵振维  康士峰  朱庆林  王晓宾 《全球定位系统》2008,33(5):24-26

基于一定的大气折射率剖面模型和搜索方法,可以由GPS天顶延迟反演大气折射率剖面。利用上海气象站的探空数据和上海IGS站的GPS数据,对基于单站地基GPS天顶延迟的大气折射率剖面反演方法进行了验证。结果表明,根据目前处理得到的天顶延迟,反演剖面与实际剖面吻合较好。  相似文献   

PCA-SIFT 特征匹配算法研究     

李钦  游雄  李科  张彦喜 《测绘工程》2016,25(4):19-24

SIFT特征具有旋转、尺度和明暗变化的不变性,在图像匹配中得到广泛应用。针对SIFT特征匹配中耗时长、匹配点对少、准确率低的问题,提出PCA-SIFT特征匹配的方法。使用更加精简的方法构建特征点描述向量,通过预先构建的投影矩阵对描述向量进行主成分分析,降低描述向量的维度从而提高了特征匹配的速度,同时降维也对描述向量进行了去噪提纯,使得匹配更加准确。实验证明,利用PCA-SIFT特征进行匹配在降低匹配耗时的同时,增加了匹配点对,匹配准确率也得到提高。  相似文献   

Dynamic soil–structure interaction analysis using Lanczos vectors with adaptive time integration technique     

R. Venugopala Rao  N. S. V. Kameswara Rao 《国际地质力学数值与分析法杂志》1999,23(11):1141-1158

An analytical procedure to obtain the response of soil–structure interaction problems, time domain is described. The procedure makes use of large domain for descritization along with co-ordinate transformation using Lanczos vectors. The responses are obtained in time domain using an adaptive direct integration method. The scheme has the ability to estimate errors due to temporal discretization as well as co-ordinate transformation. The procedure has been applied to half-space problems and non-convex domains for validation of the scheme, and the scheme obeys causality condition in both the situations. The present method has all the advantages of time domain scheme which is local both in space and time with small computational effort. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

全球地表(海表)前期温度与中国及华中地区夏季降水的关联   总被引：2，自引：1，他引：1  

张礼平  丁一汇 《气象学报》2005,63(3):325-332

用SVD方法分析了1月全球地表(海表)温度与中国及华中区域夏季降水场的关系,分析结果表明:1月热带地区地表(海表)温度与夏季长江中游降水关系最好,呈正相关。与新疆西北部、青海东北部、长江上游有弱的正相关,与山东大部分地区、浙江沿海地区有弱的负相关。前期热带海洋海表温度偏高,可能预示长江中游夏季降水偏多,反之亦然。由于分析的范围为全球的陆面和海面,因而其关联范围较已有成果有很大的扩展,不仅仅为热带西太平洋、印度洋和南海,而是整个热带地区,包括热带的海洋和陆地。预报信号也提前了4个月,可为预测长江中游夏季降水提供更长时效的参考和依据。  相似文献   

一种神经网络计算器VLSI实现可行性研究     

冯天瑾  于青松  刘珑珑 《中国海洋大学学报(自然科学版)》1998,(2)

本文以一种新型激光扫描３－Ｄ视觉传播系统中快速求解３－Ｄ坐标值等为例子,展示ＢＰ神经网络的并行分布处理在本质上具有高速度优势及硬件容错能力;以及如何实现基于模拟神经网络的二进制数字量映射的无误差操作：进而阐明用模拟ＶＬＳＩ技术实现训练后神经网络芯片的可行性和推广意义。  相似文献   

Application of Normalized Full Gradient Method to Self Potential (SP) Data     

Petek Sındırgı  Oya Pamukçu  Şenol Özyalın 《Pure and Applied Geophysics》2008,165(2):409-427

Recently, Normalized Full Gradient (NFG) method has widespread applications to natural potential fields, especially in gravity and magnetic. In this study, usage of NFG in Self-Potential (SP) data evaluation is tested. Results are compared to other SP interpretation methods. The NFG method is applied to synthetic and field SP data. As a consequence of application of the method to the anomalies of spherical, cylindrical and vertical sheet models, whose theoretical structures are explicit, the structures were found very close to their actual locations. In order to see the capability of the method in detecting the number of sources, NFG method was applied to different spherical models at different depths and locations. The least-squares inverse solution was applied to the same models and NFG method was found more powerful in detecting model structure. Sensitivity of NFG method for application to noisy data is also tested. An anomaly is generated by adding a random noise to two close sphere SP anomalies. The method seems to work for the two close spheres at high S/N ratio. Then, NFG method was applied to two field examples. The first one is the cross section taken from the SP anomaly map of the Ergani-Süleymanköy (Turkey) copper mine. The depth of the mineral deposit at that site was found about 38 m from the ground level. This result is well matched to previous studies. NFG was also applied to SP data from Seferihisar Izmir (Western Turkey) geothermal field and the location of the point source was determined. The field data of this site have already been modeled by the thermoelectric source (coupling) solution method. When these two methods are compared, they seem to support each other. It is concluded that the NFG method works perfectly when the structure model is simple. It is observed that natural potential sources close to earth’s surface are identified by the method more accurately at greater harmonics, while deep sources are identified at lesser harmonics. It produces reasonable results for noisy multi-source models than the other parameter identification methods (inverse solution, power spectrum, etc.).  相似文献   

变形模式的拓扑约束识别   总被引：2，自引：0，他引：2  

蒋征  张正禄 《测绘学报》1999,28(4):330-334

根据变形观测的位移矢量,识别菜体及其运动模式是变形分析一项重要内容,以往的作法是根据矢量作图人工判断变形体,然后选择适当的模式进行拟合。本文提出一种在点位邻接拓扑关系加其他先验信息约束的识别思想及相应算法别人,从而可实现变表模式的自动识别。最后的算例说明了该算法的实现过程,有效性及潜在意义。  相似文献   

A refined analytical analysis of submerged pipelines in seabed laying     

F. Guarracino  V. Mallardo 《Applied Ocean Research》1999,21(6):1054-293

The paper analyzes the elastic deflection of submerged pipelines laid with a stinger by taking into account the overall effects of the ovalization of the cross section. The analysis is performed by means of a singular perturbation technique and the analytical solution obtained is shown to offer different advantages over the finite element method. Two examples demonstrate the effectiveness of the procedure by means of a comparison with results from other less refined analytical solutions and from the commercial finite element code .  相似文献   

冬季黑潮区域海温异常对北太平洋风暴轴的影响   总被引：21，自引：0，他引：21       下载免费PDF全文

朱伟军  孙照渤 《应用气象学报》2000,11(2):145-153

该文对15个冬季北太平洋风暴轴区域500 hPa天气尺度滤波位势高度方差与北太平洋海表温度进行了奇异值分解 (SVD) 分析.结果表明, SVD得到的第二对空间典型分布反映了冬季黑潮区域的海温异常与风暴轴的异常变化密切相关.进一步的分析显示, 黑潮区域海温异常可能通过加强风暴轴入口区的斜压性, 激发或加强500 hPa高度场上的WP遥相关型, 主要影响冬季北太平洋风暴轴在入口区的强度变化和南北位移.  相似文献