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一种TI介质纯qP波正演方法及其在逆时偏移中的应用 被引量:9
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作者 杨鹏 李振春 谷丙洛 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2017年第11期4447-4467,共21页
基于Tsvankin提出的精确频散关系,利用近似展开的方法,推导出解耦合的TTI介质纯qP波近似方程,并将方程中的偏微分算子分解成一个laplace算子和一个标量算子,用于代表qP波的精确传播方向,构建时间域二阶纯qP波方程.此推导过程无需设置横... 基于Tsvankin提出的精确频散关系,利用近似展开的方法,推导出解耦合的TTI介质纯qP波近似方程,并将方程中的偏微分算子分解成一个laplace算子和一个标量算子,用于代表qP波的精确传播方向,构建时间域二阶纯qP波方程.此推导过程无需设置横波速度为零,能够更加精确地描述qP波的运动学特征.这个方程相比于求解波数域二阶解耦qP波方程,计算效率高,存储需求小;相比于基于Alkhalifah频散关系推导的时间域二阶纯qP波方程,假象干扰压制好,数值误差小,更具一般性.但此方法求解波矢量时采用波场梯度一阶渐近近似,会造成垂直于对称轴方向的波场振幅不准确.为了较正振幅,将椭圆分解方法应用于此方程中,构建纯qP波椭圆分解方程,使得振幅更加均衡,并与Xu等提出的方程比较分析,应用本文构建的纯qP波椭圆分解方程得到的波场振幅值更加准确.本文首先选取了均匀TI介质模型进行了qP波正演模拟,并抽取波场单道波形进行振幅分析,验证了本文构建的纯qP波方程和纯qP波椭圆分解方程的正确性及有效性;然后选取BP TTI模型进行了qP波正演模拟,将其qP波正演结果和均匀TI介质模型振幅分析结果相结合,突出了本文构建的纯qP波椭圆分解方程的优势及适应性;最后选取逆冲模型和BPTTI模型,应用本文构建的纯qP波椭圆分解方程对其进行逆时偏移成像,验证了本文构建的纯qP波椭圆分解方程在逆时偏移中的可行性和适用性. 展开更多
关键词 TI介质 纯qP波 频散关系 椭圆分解 逆时偏移
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基于MDL Shape Model及EFD的行人轮廓2D+time表示 被引量:2
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作者 王绍宇 戚飞虎 夏小玲 《中国图象图形学报》 CSCD 北大核心 2008年第10期1898-1901,共4页
针对智能监控的行人轮廓特征提取,先利用MDL shape model得到紧致但能充分表征轮廓几何特征标志点之间的对应关系,再利用椭圆傅里叶分解把行人轮廓表示为一系列不同频率下椭圆傅里叶系数组成的向量,最后得到行人2D+time轮廓的描述向量... 针对智能监控的行人轮廓特征提取,先利用MDL shape model得到紧致但能充分表征轮廓几何特征标志点之间的对应关系,再利用椭圆傅里叶分解把行人轮廓表示为一系列不同频率下椭圆傅里叶系数组成的向量,最后得到行人2D+time轮廓的描述向量。实验结果表明,此方法不但可以在几何上直观地表示行人轮廓,而且大大降低了轮廓向量的维数。 展开更多
关键词 最小描述长度模型 椭圆傅里叶分解 主分量分析 procrustes对齐
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Multi-solution of Semilinear Elliptic Equation on R^N
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作者 冯秀芳 郑驻军 +1 位作者 赵秀娥 郑君英 《Chinese Quarterly Journal of Mathematics》 CSCD 2001年第2期98-103,共6页
In this paper, we give a Z 2 index theory of generalized critical point. By this theory we get a sufficient condition on the existing result of a class functional, as an example we give a new result that the equa... In this paper, we give a Z 2 index theory of generalized critical point. By this theory we get a sufficient condition on the existing result of a class functional, as an example we give a new result that the equation-Δu+u=|u| p-1 u, x∈R N,(1)has infinite solutions. 展开更多
关键词 generalized critical point Z 2 index semilinear equation
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基于多播RSA的“零密钥更新”方案的安全分析
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作者 吉克林皓 杨军 《计算机应用》 CSCD 北大核心 2011年第3期793-797,共5页
Lin,Tang和Wang(LTW)基于一种星型密钥分发体系结构提出了一种多素数RSA,并利用它构造了一种无需密钥更新过程的集中式组密钥管理方案。按照组密钥管理的几个主要安全需求,运用密码学的工程实践视角和计算数论的方法,对该方案提出了环... Lin,Tang和Wang(LTW)基于一种星型密钥分发体系结构提出了一种多素数RSA,并利用它构造了一种无需密钥更新过程的集中式组密钥管理方案。按照组密钥管理的几个主要安全需求,运用密码学的工程实践视角和计算数论的方法,对该方案提出了环幂等元攻击、选择明文攻击、求高次整根攻击以及基于椭圆曲线分解方法和中国剩余定理的串谋攻击。数学与密码分析表明:在一定的条件下可以高效实现这些攻击,而密钥服务器的加密指数的"零更新"特性正是这些安全隐患之源。 展开更多
关键词 信息安全 组密钥管理 “1影响n”问题 多素数RSA 椭圆曲线分解方法 中国剩余定理
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An Improved F-Expansion Method and Its Application to Coupled Drinfel'd-SokolovWilson Equation 被引量:6
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作者 ZHAO Xue-Qin ZHI Hong-Yan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第8期309-314,共6页
With the aid of computerized symbolic computation, an improved F-expansion method is presented to uniformly construct more new exact doubly periodic solutions in terms of rational formal Jscobi elliptic function of no... With the aid of computerized symbolic computation, an improved F-expansion method is presented to uniformly construct more new exact doubly periodic solutions in terms of rational formal Jscobi elliptic function of nonlinear partial differential equations (NPDFs). The coupled Drinfel'd-Sokolov-Wilson equation is chosen to illustrate the method. As a result, we can successfully obtain abundant new doubly periodic solutions without calculating various Jacobi elliptic functions. In the limit cases, the rational solitary wave solutions and trigonometric function solutions are obtained as well. 展开更多
关键词 Jacobi elliptic function doubly periodic solution rational solitary wave solution
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Solving Nonlinear Wave Equations by Elliptic Equation 被引量:12
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作者 FUZun-Tao LIUShi-Da LIUShi-Kuo 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第5期531-536,共6页
The elliptic equation is taken as a transformation and applied to solve nonlinear wave equations. It is shown that this method is more powerful to give more kinds of solutions, such as rational solutions, solitary wav... The elliptic equation is taken as a transformation and applied to solve nonlinear wave equations. It is shown that this method is more powerful to give more kinds of solutions, such as rational solutions, solitary wave solutions,periodic wave solutions and so on, so it can be taken as a generalized method. 展开更多
关键词 elliptic equation Jacobi elliptic function nonlinear equation periodic wave solution
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Exact Solutions Expressible in Rational Formal Hyperbolic and Elliptic Functions for Nonlinear Differential-Difference Equation 被引量:3
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作者 BAI Cheng-Jie ZHAO Hong HAN Ji-Guang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第8期303-308,共6页
A new approach is presented by means of a new general ansitz and some relations among Jacobian elliptic functions, which enables one to construct more new exact solutions of nonlinear differential-difference equations... A new approach is presented by means of a new general ansitz and some relations among Jacobian elliptic functions, which enables one to construct more new exact solutions of nonlinear differential-difference equations. As an example, we apply this new method to Hybrid lattice, diseretized mKdV lattice, and modified Volterra lattice. As a result, many exact solutions expressible in rational formal hyperbolic and elliptic functions are conveniently obtained with the help of Maple. 展开更多
关键词 nonlinear differential-difference equations new approach exact solutions
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Boundedness of Solutions for Elliptic Variational Inequalities
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作者 Ye Ruifen(Department of Mathematics, Guangzhou Teachers’ College, 510400) 《Chinese Quarterly Journal of Mathematics》 CSCD 1996年第1期56-62,共7页
The boundedness is proved under more general structural conditions to solutions of elliptic variational inequalities and a priori estimates are obtained to maximum modulus of solutions for some special cases.
关键词 elliptic variational inequality generalized solution bounded solution:maximum modulus priori estimate
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Periodic Wave Solutions for Konopelchenko-Dubrovsky Equation 被引量:1
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作者 ZHANGJin-liang ZHANGLing-yuan WANGMing-liang 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2005年第1期72-78,共7页
By using F-expansion method proposed recently, we derive the periodic wave solution expressed by Jacobi elliptic functions for Konopelchenko-Dubrovsky equation. In the limit case, the solitary wave solution and other ... By using F-expansion method proposed recently, we derive the periodic wave solution expressed by Jacobi elliptic functions for Konopelchenko-Dubrovsky equation. In the limit case, the solitary wave solution and other type of the traveling wave solutions are derived. 展开更多
关键词 Konopelchenko-Dubrovsky equation F-expansion method Jacobi elliptic functions periodic wave solution solitary wave solution
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Envelope Periodic Solutions to Coupled Nonlinear Equations
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作者 LIUShi-Da FuZun-Tao 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第2期167-172,共6页
The envelope periodic solutions to some nonlinear coupled equations are obtained by means of the Jacobielliptic function expansion method. And these envelope periodic solutions obtained by this method can degenerate t... The envelope periodic solutions to some nonlinear coupled equations are obtained by means of the Jacobielliptic function expansion method. And these envelope periodic solutions obtained by this method can degenerate tothe envelope shock wave solutions and/or the envelope solitary wave solutions. 展开更多
关键词 Jacobi elliptic function nonlinear coupled equations envelope periodic solution
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New Exact Solutions of Multi-component mKdV Equation
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作者 YE Cai-Er 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第5期777-780,共4页
In this paper, new Jacobi elliptic function solutions of multi-component mKdV equation are obtained directly in a unified way. When the modulus m → 1, those periodic solutions degenerate as the corresponding hyperbol... In this paper, new Jacobi elliptic function solutions of multi-component mKdV equation are obtained directly in a unified way. When the modulus m → 1, those periodic solutions degenerate as the corresponding hyperbolic function solutions. Then, to the three-component mKdV equation, five types of effective solution are presented in detail. 展开更多
关键词 multi-component mKdV equation exact solution Jacobi elliptic function hyperbolic function
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Periodic Solutions for Two Coupled Nonlinear-Partial Differential Equations
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作者 LIU Shi-Da FU Zun-Tao LIU Shi-Kuo 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第3X期425-427,共3页
In this paper, by applying the Jacobi elliptic function expansion method, the periodic solutions for two coupled nonlinear partial differential equations are obtained.
关键词 Jacobi elliptic function periodic wave solution nonlinear partial differential equation
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Periodic Solutions for a Class of Nonlinear Differential-Difference Equations
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作者 LIU Shi-Kuo FU Zun-Tao +1 位作者 WANG Zhang-Gui LIU Shi-Da 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第5期1155-1158,共4页
In this paper, by applying the Jacobi elliptic function expansion method, the periodic solutions for three nonlinear differential-difference equations are obtained.
关键词 Jacobian elliptic function periodic solutions nonlinear differential-difference equation
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New Periodic Wave Solutions and Their Interaction for (2+1)-dimensional KdV Equation
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作者 GE Dong-jie MA Hong-cai YU Yao-dong 《Chinese Quarterly Journal of Mathematics》 CSCD 2009年第4期525-536,共12页
A class of new doubly periodic wave solutions for (2+1)-dimensional KdV equation are obtained by introducing appropriate Jacobi elliptic functions and Weierstrass elliptic functions in the general solution(contain... A class of new doubly periodic wave solutions for (2+1)-dimensional KdV equation are obtained by introducing appropriate Jacobi elliptic functions and Weierstrass elliptic functions in the general solution(contains two arbitrary functions) got by means of multilinear variable separation approach for (2+1)-dimensional KdV equation. Limiting cases are considered and some localized excitations are derived, such as dromion, multidromions, dromion-antidromion, multidromions-antidromions, and so on. Some solutions of the dromion-antidromion and multidromions-antidromions are periodic in one direction but localized in the other direction. The interaction properties of these solutions, which are numerically studied, reveal that some of them are nonelastic and some are completely elastic. Furthermore, these results are visualized. 展开更多
关键词 (2+1)-dimensional KdV equation multilinear variable separation approach elliptic functions periodic wave solutions localized excitations interaction property nonelastic completely elastic
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On the elliptic curve y^2=x^3-2r Dx and factoring integers
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作者 LI XiuMei ZENG JinXiang 《Science China Mathematics》 SCIE 2014年第4期719-728,共10页
Let D=pq be the product of two distinct odd primes.Assuming the parity conjecture,we construct infinitely many r≥1 such that E2rD:y2=x3-2rDx has conjectural rank one and vp(x([k]Q))≠vq(x([k]Q))for any odd integer k,... Let D=pq be the product of two distinct odd primes.Assuming the parity conjecture,we construct infinitely many r≥1 such that E2rD:y2=x3-2rDx has conjectural rank one and vp(x([k]Q))≠vq(x([k]Q))for any odd integer k,where Q is the generator of the free part of E(Q).Furthermore,under the generalized Riemann hypothesis,the minimal value of r is less than c log4 D for some absolute constant c.As a corollary,one can factor D by computing the generator Q. 展开更多
关键词 elliptic curve integer factoring Selmer group
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A PRECONDITIONER FOR THREE-DIMENSIONAL DOMAIN DECOMPOSITION METHODS WITH LAGRANGE MULTIPLIERS
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作者 HUQiya LIANGGuoping LIUJinzhao 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2003年第4期513-526,共14页
In this paper we consider domain decomposition methods for three-dimensional elliptic problems with Lagrange multipliers, and construct a kind of simple preconditioner for the corresponding interface equation. It will... In this paper we consider domain decomposition methods for three-dimensional elliptic problems with Lagrange multipliers, and construct a kind of simple preconditioner for the corresponding interface equation. It will be shown that condition number of the resulting preconditioned interface matrix is almost optimal. 展开更多
关键词 domain decomposition non-matching grids lagrange multipliers PRECONDITIONER condition number
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ON THE EXISTENCE OF POSITIVESOLUTIONS OF AN ELLIPTICBOUNDARY VALUE PROBLEMON THE EXISTENCE OF POSITIVESOLUTIONS OF AN ELLIPTICBOUNDARY VALUE PROBLEM
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作者 LIUZHAOLI LIFUYI 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2000年第4期499-510,共12页
Using variational method, the authors get an existence result for positive solutions of a superlinear elliptic boundary value problem without assuming the P.S. condition. To prove the results in this paper, the author... Using variational method, the authors get an existence result for positive solutions of a superlinear elliptic boundary value problem without assuming the P.S. condition. To prove the results in this paper, the authors adopt the method of gradient flow and use a new class of truncation functions. 展开更多
关键词 Superlinear elliptic BVP Positive solution Variational method Gradient flow
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Inverse Coefficient Problems for Elliptic Hemivariational Inequalities
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作者 Cui'e XIAO Zhenhai LIU 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2010年第4期473-480,共8页
This paper is devoted to a class of inverse coefficient problems for nonlinear elliptic hemivariational inequalities. The unknown coefficient of elliptic hemivariational inequalities depends on the gradient of the sol... This paper is devoted to a class of inverse coefficient problems for nonlinear elliptic hemivariational inequalities. The unknown coefficient of elliptic hemivariational inequalities depends on the gradient of the solution and belongs to a set of admissible coefficients. It is shown that the nonlinear elliptic hemivariational inequalities are uniquely solvable for the given class of coefficients. The result of existence of quasisolutions of the inverse problems is obtained. 展开更多
关键词 Elliptic hemivariational inequality Inverse coefficient problem Existence of quasisolution
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On the Numerical Solution of Some Eikonal Equations:An Elliptic Solver Approach
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作者 Alexandre CABOUSSAT Roland GLOWINSKI Tsorng-Whay PAN 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2015年第5期689-702,共14页
The steady Eikonal equation is a prototypical first-order fully nonlinear equation. A numerical method based on elliptic solvers is presented here to solve two different kinds of steady Eikonal equations and compute s... The steady Eikonal equation is a prototypical first-order fully nonlinear equation. A numerical method based on elliptic solvers is presented here to solve two different kinds of steady Eikonal equations and compute solutions, which are maximal and minimal in the variational sense. The approach in this paper relies on a variational argument involving penalty, a biharmonic regularization, and an operator-splitting-based time-discretization scheme for the solution of an associated initial-value problem. This approach allows the decoupling of the nonlinearities and differential operators.Numerical experiments are performed to validate this approach and investigate its convergence properties from a numerical viewpoint. 展开更多
关键词 Eikonal equations Maximal solutions Regularization methods Operator slalitting Finite element methods
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