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High frequency S wave envelope synthesis using a multiple non-isotropic scattering model: application to aftershocks from the 2008 Wenchuan earthquake 被引量:1
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作者 Lin Gao Jing Yueling Li Jianbo 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2013年第2期185-194,共10页
Based on the formulation of a multiple non-isotropic scattering process, a characteristic source time is introduced to define the initial impulse width of energy density at the source. An analytical expression of the ... Based on the formulation of a multiple non-isotropic scattering process, a characteristic source time is introduced to define the initial impulse width of energy density at the source. An analytical expression of the initial intensity spectral density of a seismic wave is incorporated into the integral equation of seismic wave energy density. And, a recursive formula of Green's function is derived to obtain the higher order Green's function, which is included to describe the stronger non-isotropic scattering process. Then, the effect of the scattering pattern on the energy density envelope is investigated by the modified scattering theory. Significant differences arc found in the decay of the energy density envelopes with distances using different scattering patterns. The envelope synthesized by the forward dominated scattering pattern is larger than the results obtained by the isotropic and backward dominated scattering pattern. Different scattering patterns are also used to fit the observation data from the aftershocks of the 2008 Wenchuan earthquake. It is concluded that the envelopes synthesized by the forward scattering pattern can match the data better than the isotropic and backward dominated scattering cases, and a new interpretation of the coda wave is given. Finally, using the forward dominated scattering pattern, the envelope broadening of the observed data is reproduced. 展开更多
关键词 non-isotropic scattering coda wave envelope broadening energy transport theory (radiative transfer theory) directional scattering coefficient ground motion
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A NON-ISOTROPIC MULTIPLE-SCALE TURBULENCE MODEL
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作者 陈谦斌 郭宽良 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1991年第10期981-991,共11页
This paper describes a newly developednon-isotropic multiple-scale turbulence model (MS/ASM) for complex flow calculations. This model focuses on the direct modeling of Reynolds stresses and utilizes split-spectrum co... This paper describes a newly developednon-isotropic multiple-scale turbulence model (MS/ASM) for complex flow calculations. This model focuses on the direct modeling of Reynolds stresses and utilizes split-spectrum concepts to model multiple-scale effects in turbulence. Validation studies on free shear flows, rotating flows and recirculating flows show that the current model performs significantly better than the single-scale k-e model. The present model is relatively inexpensive in terms of CPU time which makes in suitable for broad engineering flow applications. 展开更多
关键词 turbulence model multiple-scale non-isotropic
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基于HHT和CSSD的多域融合自适应脑电特征提取方法 被引量:36
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作者 李明爱 崔燕 +1 位作者 杨金福 郝冬梅 《电子学报》 EI CAS CSCD 北大核心 2013年第12期2479-2486,共8页
为改善运动想象脑电信号特征提取的自适应性和实时性,提出一种基于希尔伯特-黄变换(HHT)与共空域子空间分解算法(CSSD)的特征提取方法(HCSSD).在对脑电信号进行预处理的基础上,定义一种相对距离准则优选脑电极组合;计算脑电的Hilbert瞬... 为改善运动想象脑电信号特征提取的自适应性和实时性,提出一种基于希尔伯特-黄变换(HHT)与共空域子空间分解算法(CSSD)的特征提取方法(HCSSD).在对脑电信号进行预处理的基础上,定义一种相对距离准则优选脑电极组合;计算脑电的Hilbert瞬时能量谱和边际能量谱,以获取脑电的时-频特征,并基于CSSD提取其空域特征,采用串行特征融合策略得到脑电的时-频-空特征;设计学习矢量量化神经网络分类器,实现脑电数据分类.在训练集与测试集间隔一周且减少导联数量的情况下,基于HCSSD对左手小指和舌头的运动想象ECoG脑电数据的平均识别率为92%.实验结果表明:HCSSD在增强特征提取方法的自适应性、改善实时性的同时,提高了脑电信号识别率,为便携式BCI系统在康复领域的应用创造了条件. 展开更多
关键词 脑机接口 运动想象 希尔伯特-黄变换 共空域子空间分解 特征融合 自适应 brain-computer interface (BCI) motor imagery (MI) hilbert-huang transform (HHT) common spatial sub-space decomposition (CSSD )
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Non-isotropic weighted L^p estimates for the -equation on piecewise smooth strictly pseudoconvex domains
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作者 Heungju AHN Hong Rae CHO Jong-Do PARK 《Science China Mathematics》 SCIE 2008年第12期2161-2171,共11页
In this paper we obtain non-isotropic weighted Lp estimates with the boundary distance weight function for the-equation on piecewise smooth strictly pseudoconvex domains under a hypoth- esis of complex transversality ... In this paper we obtain non-isotropic weighted Lp estimates with the boundary distance weight function for the-equation on piecewise smooth strictly pseudoconvex domains under a hypoth- esis of complex transversality in Cn using the explicit formula of solutions by Berndtsson-Andersson. 展开更多
关键词 non-isotropic norm Cauchy-Riemann EQUATION PIECEWISE strictly PSEUDOCONVEX domain
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On Effectiveness of Protocol Creating Maximum Entanglement of Two Charge-Phase Qubits by Cavity Field
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作者 LI Chong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第5X期935-942,共8页
We revisit the protocols to create maximally entangled states between two Josephson junction (33) charge phase qubits coupled to a microwave field in a cavity as a quantum data bus. We analyze a novel mechanism of q... We revisit the protocols to create maximally entangled states between two Josephson junction (33) charge phase qubits coupled to a microwave field in a cavity as a quantum data bus. We analyze a novel mechanism of quantum decoherence due to the adiabatic entanglement between qubits and the data bus, the off-resonance microwave field. We show that even if the variable of the data bus can be adiabatically eliminated, the entanglement between the qubits and data bus remains and can decohere the superposition of two-particle state. Fortunately we can construct a decoherencefree subspace of two-dimension to against this adiabatic decoherence. To carry out the analytic study for this decoherence problem, we develop Frohlich transformation to re-derive the effective Hamiltonian of these systems, which is equivalent to that obtained from the adiabatic elimination approach. 展开更多
关键词 SQUID quantum entanglement conccurrence decoherence free sub-space
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Entanglement sudden death of two atoms interacting with a cavity via the two-photon process in a strong-driving-assisted system
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作者 陈丽 邵晓强 张寿 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第11期4676-4682,共7页
We examine the entanglement dynamics between two strongly driven atoms off-resonantly coupled with a singlemode cavity via the two-photon process with the help of negativity in two different types of initial states. T... We examine the entanglement dynamics between two strongly driven atoms off-resonantly coupled with a singlemode cavity via the two-photon process with the help of negativity in two different types of initial states. The results show that entanglement sudden death may occur under both the above conditions and the sudden death effect can be monitored by modulating the atom-cavity detunings. Furthermore, we also find an atomic decoherence-free subspace so that the initial entanglement between two atoms remains invariable in application. 展开更多
关键词 entanglement sudden death NEGATIVITY atom-cavity detuning decoherence-free sub-space
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Maximal Operators and Singular Integrals with Non-Isotropic Dilation on Product Domains
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作者 Zhong Kai LI Bo Lin MA Huo Xiong WU 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2010年第10期1847-1864,共18页
In this paper, the authors study the with non-isotropic dilation on product domains. LP-mapping properties of certain maximal operators As an application, the LP-boundedness of the corre- sponding nomisotropic multipl... In this paper, the authors study the with non-isotropic dilation on product domains. LP-mapping properties of certain maximal operators As an application, the LP-boundedness of the corre- sponding nomisotropic multiple singular integral operator is also obtained. Here the integral kernel functions Ω belong to the spaces L(logL)a(E1 × E2) for some a 〉 0, which is optimal. 展开更多
关键词 non-isotropic singular integral maximal function product domain rough kernel
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An infrared human face recognition method based on 2DPCA
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作者 刘侠 李廷军 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2009年第2期265-268,共4页
Aimed at the problems of infrared image recognition under varying illumination,face disguise,etc.,we bring out an infrared human face recognition algorithm based on 2DPCA.The proposed algorithm can work out the covari... Aimed at the problems of infrared image recognition under varying illumination,face disguise,etc.,we bring out an infrared human face recognition algorithm based on 2DPCA.The proposed algorithm can work out the covariance matrix of the training sample easily and directly;at the same time,it costs less time to work out the eigenvector.Relevant experiments are carried out,and the result indicates that compared with the traditional recognition algorithm,the proposed recognition method is swift and has a good adaptability to the changes of human face posture. 展开更多
关键词 infrared image face recognition feature sub-space K-L transformation
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MATHEMATICAL ANALYSIS OF MUTATION OPERATOR AND ITS IMPROVED STRATEGY IN GENETIC ALGORITHMS
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作者 Zhang Liangjie Mao Zhihong Li Yanda(Dept. of Automation, Tsinghua Univ., Beijing, 100084) 《Journal of Electronics(China)》 1997年第2期154-158,共5页
This paper analyzes the optimization problem of mutation probability in genetic algorithms by applying the definition of i-bit improved sub-space. Then fuzzy reasoning technique is adopted to determine the optimal mut... This paper analyzes the optimization problem of mutation probability in genetic algorithms by applying the definition of i-bit improved sub-space. Then fuzzy reasoning technique is adopted to determine the optimal mutation probability in different conditions. The superior convergence property of the new method is evaluated by applying it to two simulation examples. 展开更多
关键词 GENETIC algorithm(GA) i-bit IMPROVED sub-space FUZZY REASONING
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Initial-boundary Value Problem for a Class of Quasilinear Degenerate Parabolic Equations
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作者 Nie Lei Xu Chaojiang 《Wuhan University Journal of Natural Sciences》 CAS 1996年第2期179-183,共5页
in this work,we study the quasilinear initial-boundary value problem , where is a system of real smooth vector fields which is defined on an open domain M of R'', and satisfies the Hormanderls condition,.Assu... in this work,we study the quasilinear initial-boundary value problem , where is a system of real smooth vector fields which is defined on an open domain M of R'', and satisfies the Hormanderls condition,.Assume that is non characteristic for the system X,,..',Xm. Under some hypothesis for the boundary of domain and the elliptic structure condition for nonlinear coerfficients Aij, Bj, C,(i, j= 1, ..', m), we have proved that the existence and regularity of solution for aboveinitialboudary value problems. 展开更多
关键词 degenerate parabolic equation vector fields non-isotropic Holder's space initial-boundary value problem
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Study on intercarrier interference in mobile MIMO-OFDM based on the geometrical one-ring model
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作者 Li Juhu Zhi Xiyun +1 位作者 He Zhiqiang Wu Weiling 《High Technology Letters》 EI CAS 2012年第1期20-25,共6页
This paper investigates the distribution of intercarrier interference (ICI) in multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems based on the geometrical one-ring model.... This paper investigates the distribution of intercarrier interference (ICI) in multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems based on the geometrical one-ring model. Using the spatial and temporal correlation of a geometrical one-ring model, a close-formed expression of intercarrier interference due to the Doppler effect caused by the movement of receiver is derived under the isotropic scattering conditions and non-isotropic scattering conditions. The analytical results are verified by Monte Carlo simulations. We use the generated channels to investigate MIMO-OFDM intercarrier interference under various channel parameters. It can be shown that more than 95% oflCI power comes from five neighboring subcarriers. 展开更多
关键词 intercarrier interference (ICI) one-ring model spatial and temporal correlation isotropicscattering non-isotropic scattering
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The Gagliardo-Nirenberg-Sobolev Inequality for Non-lsotropic Riesz Potentials
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作者 Inan Cinar 《Journal of Mathematics and System Science》 2015年第2期83-85,共3页
In this study, the inequality of Gagliardo-Nirenberg-Sobolev type are established for non-isotropic Generalized Riesz Potential depending on 2-distance.
关键词 non-isotropic distance POTENTIALS
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Spatial Nonparametric Regression Estimation: Non-isotropic Case
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作者 Zu-di Lu, Xing ChenInstitute of Systems Science, Academy of Mathematics and Systems Sciences, Chinese Academy of Sciences. Beijing 100080, ChinaDepartment of Statistics, Yunnan University, Kunming 650091, China 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2002年第4期641-656,共16页
Data collected on the surface of the earth often has spatial interaction. In this paper, a non-isotropic mixing spatial data process is introduced, and under such a spatial structure a nonparametric kernel method is s... Data collected on the surface of the earth often has spatial interaction. In this paper, a non-isotropic mixing spatial data process is introduced, and under such a spatial structure a nonparametric kernel method is suggested to estimate a spatial conditional regression. Under mild regularities, sufficient conditions are derived to ensure the weak consistency as well as the convergence rates for the kernel estimator. Of interest are the following: (1) All the conditions imposed on the mixing coefficient and the bandwidth are simple; (2) Differently from the time series setting, the bandwidth is found to be dependent on the dimension of the site in space as well; (3) For weak consistency, the mixing coefficient is allowed to be unsummable and the tendency of sample size to infinity may be in different manners along different direction in space; (4) However, to have an optimal convergence rate, faster decreasing rates of mixing coefficient and the tendency of sample size to infinity along each direction are required. 展开更多
关键词 Bandwidth kernel estimator mixing non-isotropic spatial data spatial conditional regression weak consistency and rates
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MIXED LEGENDRE-HERMITE PSEUDOSPECTRAL METHOD FOR HEAT TRANSFER IN AN INFINITE PLATE 被引量:4
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作者 Tian-jun Wang Ben-yu Guo 《Journal of Computational Mathematics》 SCIE EI CSCD 2005年第6期587-602,共16页
A new mixed Legendre-Hermite interpolation is introduced. Some approximation results are established. Mixed Legendre-Hermite pseudospectral method is proposed for non-isotropic heat transfer in an infinite plate. Its ... A new mixed Legendre-Hermite interpolation is introduced. Some approximation results are established. Mixed Legendre-Hermite pseudospectral method is proposed for non-isotropic heat transfer in an infinite plate. Its convergence is proved. Numerical results show the efficiency of this approach. 展开更多
关键词 non-isotropic heat transfer Infinite plate Mixed Legendre-Hermite pseudospectral method
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Poincaré and Sobolev Inequalities for Vector Fields Satisfying Hrmander's Condition in Variable Exponent Sobolev Spaces 被引量:2
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作者 Xia LI Guo Zhen LU Han Li TANG 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2015年第7期1067-1085,共19页
In this paper, we will establish Poincare inequalities in variable exponent non-isotropic Sobolev spaces. The crucial part is that we prove the boundedness of the fractional integral operator on variable exponent Lebe... In this paper, we will establish Poincare inequalities in variable exponent non-isotropic Sobolev spaces. The crucial part is that we prove the boundedness of the fractional integral operator on variable exponent Lebesgue spaces on spaces of homogeneous type. We obtain the first order Poincare inequalities for vector fields satisfying Hormander's condition in variable non-isotropic Sobolev spaces. We also set up the higher order Poincare inequalities with variable exponents on stratified Lie groups. Moreover, we get the Sobolev inequalities in variable exponent Sobolev spaces on whole stratified Lie groups. These inequalities are important and basic tools in studying nonlinear subelliptic PDEs with variable exponents such as the p(x)-subLaplacian. Our results are only stated and proved for vector fields satisfying Hormander's condition, but they also hold for Grushin vector fields as well with obvious modifications. 展开更多
关键词 Poincare inequalities the representation formula fractional integrals on homogeneousspaces vector fields satisfying Hormander's condition stratified groups high order non-isotropic Sobolev spaces with variable exponents Sobolev inequalities with variable exponents
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THE CHARACTERISTIC POLYNOMIAL OF A GEOMETRIC LATTICE IN SYMPLECTIC GEOMETRY OVER FINITE FIELDS
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作者 陈冬生 万哲先 《Chinese Science Bulletin》 SCIE EI CAS 1991年第12期974-978,共5页
Let F be a field and V= V<sub>n</sub>(F)={(a<sub>1</sub>,…, a<sub>n</sub>)|a<sub>i</sub>∈F} be the row vector space of finite dimension n over F. Let be a finite s... Let F be a field and V= V<sub>n</sub>(F)={(a<sub>1</sub>,…, a<sub>n</sub>)|a<sub>i</sub>∈F} be the row vector space of finite dimension n over F. Let be a finite set ofsubspaces of Vsuch that U=(0). And let L= L((?)) be the set of intersections of dements of. Partial order L by reverse inclusion has V as its minimal element and as its set of atoms. We denote the partial order- 展开更多
关键词 GEOMETRIC LATTICE non-isotropic SUBSPACE CHARACTERISTIC polynomial.
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Bubble Tree ConVergence for the Harmonic Sequence of Harmonic Surfaces in CP^n
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作者 Xiao Huan MO Fang SUN 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2010年第7期1277-1286,共10页
We show that any harmonic sequence determined by a harmonic map from a compact Riemannian surface M to CP^n has a terminating holomorphic (or anti-holomorphic) map from M to CP^n, or a "bubble tree limit" consisti... We show that any harmonic sequence determined by a harmonic map from a compact Riemannian surface M to CP^n has a terminating holomorphic (or anti-holomorphic) map from M to CP^n, or a "bubble tree limit" consisting of a harmonic map f: M → CP^n and a tree of bubbles hλ^μ: S^2 --→ CP^n. 展开更多
关键词 bubble tree harmonic sequence non-isotropic energy identity
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Rough Marcinkiewicz Integrals with Mixed Homogeneity on Product Spaces
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作者 Feng LIU Huo Xiong WU 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2013年第7期1231-1244,共14页
In this paper, the parabolic Marcinkiewicz integral operators on the product spaces R^m × R^n(m, n ≥ 2) are studied. The LP-boundedness for such operators are established under rather weak size conditions of t... In this paper, the parabolic Marcinkiewicz integral operators on the product spaces R^m × R^n(m, n ≥ 2) are studied. The LP-boundedness for such operators are established under rather weak size conditions of the kernels, which essentially improve or extend certain previous results. 展开更多
关键词 Marcinkiewicz integrals non-isotropic dilations maximal functions rough kernels product spaces
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