共查询到19条相似文献,搜索用时 62 毫秒
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识别时变结构模态参数的改进子空间方法 总被引:8,自引:0,他引:8
给出了基于整体数据子空间方法的改进算法,原方法对噪声的影响极为敏感,基于原方法的关键是计算一个与原系统的广义能观阵的特征值相同的矩阵的基本事实,将求矩阵的过程转化为最小二乘的问题,然后用广义能观阵替换输出矩阵,对数据进行滤波,从而有效地降低了算法对噪声敏感性,但同时增加了计算量。利用奇异向量矩阵的正交性,将最小二乘问题中求矩阵伪逆的过程简化为求该矩阵的转置,从而降低了计算量,改进后的算法能够在提高算法对噪声的敏感性的同时降低计算量。最后利用改进后的方法辨识出一个两自由度弹簧质量块模型在三种不同的刚度变化形式下的伪模态参数,并通过与使用原方法所得的结果比较,验证了以上结论。 相似文献
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基于极大似然估计的BP算法及其在深基坑开挖参数辨识中的应用 总被引:2,自引:0,他引:2
本文采用人工神经网络BP算法对深基坑开挖工程中的参数进行辨识,将某些现场实测值作为网络输入,土层物性参数作为网络的输出, 限元计算取得学习样本来训练网络,从而地深基坑开挖工程中的参数进行辨识的目的,同时,本文提出了将极大似然估计引入BP学习算法中,可以考虑学习样本和网络输入(现场产测值)的误差,可以求得所辨识参数的可靠度,本文还对动态调整BP学习算法的学习速度因子,冲量系数以加快网络学习速度的算法进行了研究,本文算例表明本文算法训练速率可比传统BP算法快10倍以上。 相似文献
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Some new weak Knaster-Kuratouski-Mazurkiewicz (KKM) theorems are proved under the noncompact situation in the generalized finitely continuous space (GFC-space) without any convexity. As applications, the minimax inequalities of the Ky Fan type are also given under some suitable conditions. The results unify and generalize some known results in recent literatures. 相似文献
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对工程结构进行环境激励下的模态参数识别具有重要意义,而随机子空间法作为适合环境激励下模态参数识别的时域方法,由于噪声和复杂激励的原因,会产生虚假模态、真实模态遗漏、系统自动定阶难和计算效率等问题,这些问题阻碍了该方法在实际工程中的广泛应用.本文提出了基于Welch法的随机子空间方法,通过Welch法对振动响应在频域进行去噪、降低环境激励和其他不确定性因素影响的处理,把结构固有模态从噪声和激励频率中突显出来,形成富含更多结构模态的Toeplitz矩阵,然后进行奇异值分解和状态矩阵计算,最后进行特征值分析.为了实现自动定阶,对不同奇异值分量构建的状态矩阵得到的特征参数,进行模糊C均值聚类分析和模态的平均相位偏移分析,剔除虚假模态,实现结构模态参数的自动识别.并把本文所提出方法应用于一座大跨悬索桥的实测加速度响应分析,和一座七十层的高层建筑的加速度响应分析,跟频域分解法、传统随机子空间法和基于相关分析的随机子空间法的计算结果进行了比较,发现基于Welch方法的随机子空间法相比于传统随机子空间法和基于相关分析的随机子空间法,在避免模态遗漏和计算效率方面有显著提高,而相对于频域分解法则在自动识别... 相似文献
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This paper studies the effects of the magnetic field and the porosity on a poroelastic bone model for internal remodeling. The solution of the internal bone remodeling process induced by a magnetic field is presented. The bone is treated as a poroelastic material by Biot’s formulation. Based on the theory of small strain adaptive elasticity, a theoretical approach for the internal remodeling is proposed. The components of the stresses, the displacements, and the rate of internal remodeling are obtained in analytical forms, and the numerical results are represented graphically. The results indicate that the effects of the magnetic field and the porosity on the rate of internal remodeling in bone are very pronounced. 相似文献
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事件空间中非完整有势系统的参数方程 总被引:3,自引:0,他引:3
本文首先在事件空间中建立非完整有势系统的广义方程,然后给出此空间中表示Nielsen算子和Euler算子之间关系的两个定理,最后由这些定理得到广义Nielsen方程。 相似文献
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奇异摄动理论中的人工参数法及其应用 总被引:4,自引:0,他引:4
为了求解无小参数的非线性方程,可以在方程里引进一人工参数,再按人工参数展开,并同时应用Lindsedt-Poincare理论即可得到其很好的近似解。本文还阐述了如何确定最佳人工参数方程,几个实例表明这种方法是比较有效的。 相似文献
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The paper first proves a characteristic property in FC-spaces. By the use of the connectedness of sets, a parametric type of KKM theorem is then established in noncompact FC-spaces by introducing a linear ordered space. As a consequence, some recent results, such as noncompact minimax inequalities, saddle point theorem, and section theorem, are improved. The results generalize the corresponding results in the literatures. 相似文献
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ONACLASSOFNEWKKMTHEOREMWITHAPPLICATIONSZhangShisheng(张石生),ZhangXian(张宪)(ReceivedMay15,1995)Abstract:Inthispaper,aclassofnewKK... 相似文献
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A class of generalized vector variational-type inequality problems (GVVTIP) are studied in FC-spaces, which includes the most of vector equilibrium problems, vector variational inequality problems, generalized vector equilibrium problems and generalized vector variational inequality problem as special cases. By using F-KKM theorem, some new existence results for GVVTIP are established in noncompact FC-space. As consequences, some recent known results in literature are obtained under much weaker assumption. 相似文献
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Section theorems,coincidence theorems and intersection theorems on H-spaces with applications 总被引:3,自引:0,他引:3
The purpose of this paper is to study the section theorems, coincidence theorems and intersection theorems on H-spaces. As a way of application, we use these results to study the existence problems of solutions for minimax inequalities and variational inequalities. The results presented in this paper improve and extend the corresponding results in [1, 3, 5, 6, 8, 9, 12, 14,15, 17] 相似文献
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NEWVERSIONOFKKMTHEOREMINPROBABILISTICMETRICSPACESWITHAPPLICATIONSZhangShisheng(张石生)YeolJeCho(赵烈济)WuXiang(吴鲜)(ReceivedMay7,199... 相似文献
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In this paper,the Knaster-Karatowski-Mazurkiewicz technique(KKM technique,in short)is presented.By using this technique a new alternative theorem and a new coincidence theorem are established.The results obtained in this paper unify and generalize the corresponding results in the recent works. 相似文献
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MAXIMAL ELEMENTS OF A FAMILY OF GB-MAJORIZED MAPPINGS IN PRODUCT FC-SPACES AND APPLICATIONS 总被引:1,自引:1,他引:1
丁协平 《应用数学和力学(英文版)》2006,27(12):1607-1618
A new family of GB-majorized mappings from a topological space into a finite continuous topological spaces (in short, FC-space) involving a better admissible set-valued mapping is introduced. Some existence theorems of maximal elements for the family of GB-majorized mappings are proved under noncompact setting of product FCspaces. Some applications to fixed point and system of minimax inequalities are given in product FC-spaces. These theorems improve, unify and generalize many important results in recent literature. 相似文献
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1IntroductionandPreliminariesIn1968,Browder[1]provedthefollowingtheorem.Theorem11(Browder[1]) LetEbeaHausdorfftopologicallinearspace,XacompactconvexsubsetofEandF:X→2Xamappingsatisfyingthefollowingconditions:ⅰ)Foranyx∈X,F(x)isnonemptyandconvex;ⅱ)Fora… 相似文献
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A general topological version of minimax theorem 总被引:1,自引:0,他引:1
AGENERALTOPOLOGICALVERSIONOFMINIMAXTHEOREMZhangShisheng(张石生)(DepartmentofMathematics,SichuanUniversity,Chengdu610064,P.R.Chin... 相似文献