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D_∞-APPROXIMATION OF PRODUCT VARIATIONS OF TWO PARAMETER SMOOTH SEMIMARTINGALES
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作者 刘继成 《Acta Mathematica Scientia》 SCIE CSCD 2004年第2期235-246,共12页
Let X be a two parameter smooth semimartingale and (?) be its process of the product variation. It is proved that (?) can be approximated as D_∞-limit of sums of its discrete product variations as the mesh of divisio... Let X be a two parameter smooth semimartingale and (?) be its process of the product variation. It is proved that (?) can be approximated as D_∞-limit of sums of its discrete product variations as the mesh of division tends to zero. Moreover, this result can be strengthen to yield the quasi sure convergence of sums by estimating the speed of the convergence. 展开更多
关键词 Malliavin calculus D_∞-approximation two parameter smooth semimartingale product variation quasi sure
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W^t-approximation representations over quasi k-Gorenstein algebras 被引量:3
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作者 黄兆泳 《Science China Mathematics》 SCIE 1999年第9期945-956,共12页
The notions of quasi k-Gorenstein algebras and W^t-approximation representations are introduced. The existence and uniqueness (up to projective equivalences) of W^t-approximation representations over quasi k-Gorenstei... The notions of quasi k-Gorenstein algebras and W^t-approximation representations are introduced. The existence and uniqueness (up to projective equivalences) of W^t-approximation representations over quasi k-Gorenstein algebras are established. Some applications of W^t-approximation representations to homologically finite subcategories are given. 展开更多
关键词 W t -approximation representations quasik-Gorenstein algebras contravariant finiteness covariant finiteness
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Blind Multiuser Receivers for ISI CDMA Channels Using the ε-Approximation Algorithms 被引量:2
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作者 ZHANGZhi-Yong LINGYun 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2002年第4期33-37,共5页
The problem of the blind demodulation of multiuser information symbols in ahigh-rate Code Division Multiple Access (CDMA) network in the presence of InterSymbol Interference(ISI) is of considerable interest. The dispe... The problem of the blind demodulation of multiuser information symbols in ahigh-rate Code Division Multiple Access (CDMA) network in the presence of InterSymbol Interference(ISI) is of considerable interest. The dispersive CDMA channel is first cast into a Multiple-InputMultiple-Out (MIMO) signal model framework. Then , the problem of the blind channel equalization andmultiuser detection is considered. In this paper, we formulate the problem of blind channelestimation and signal detection into a quadratic programming with binary constraints. Then, theefficient ε-approximation algorithms are presented and applied to find the solution to thequadratic programming. The proposed approach does not estimate the channel directly or rely on anystatistics . Simulation results support our theoretical analysis . 展开更多
关键词 ε-approximation algorithms high-rate CDMA ISI channel MIMO
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A MFE method combined with L1-approximation for a nonlinear time-fractional coupled diffusion system
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作者 Yaxin Hou Ruihan Feng +2 位作者 Yang Liu Hong Li Wei Gao 《International Journal of Modeling, Simulation, and Scientific Computing》 EI 2017年第1期179-199,共21页
In this paper,a nonlinear time-fractional coupled diffusion system is solved by using a mixed finite element(MFE)method in space combined with L1-approximation and implicit second-order backward difference scheme in t... In this paper,a nonlinear time-fractional coupled diffusion system is solved by using a mixed finite element(MFE)method in space combined with L1-approximation and implicit second-order backward difference scheme in time.The stability for nonlinear fully discrete finite element scheme is analyzed and a priori error estimates are derived.Finally,some numerical tests are shown to verify our theoretical analysis. 展开更多
关键词 L1-approximation implicit second-order backward difference scheme timefractional coupled diffusion problem stability a priori error analysis
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D_∞-APPROXIMATION OF QUADRATIC VARIATIONS OF SMOOTH IT PROCESSES 被引量:1
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作者 HUANGZHIYOAN RENJIAGANG 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 1998年第3期305-310,共6页
The purpose of this paper is to prove that the quadratic variations of smooth It process in the sense of Malliavin-Nualart can be approximated in Sobolev spaces over the Wiener space by its discrete quadratic variations.
关键词 D -approximation Quadratic variations Smooth It Processes
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WEIGHTED BEST LOCAL APPROXIMATION IN ORLICZ SPACE 被引量:1
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作者 S. Favier C. Ridolfi 《Analysis in Theory and Applications》 2008年第3期225-236,共12页
We present a common fixed point theorem for generalized asymptotically non- expansive and noncommuting mappings in normed linear spaces.
关键词 best local approximation φ-approximations balanced integers
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CHARACTERIZATION OF BEST APPROXIMATIONS IN METRIC LINEAR SPACES
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作者 Sizwe Mabizela 《Analysis in Theory and Applications》 2003年第2期121-129,共9页
Let (X,d) be a real metric linear space, with translation-invariant metric d and C a linear subspace of X. In this paper we use functionals in the Lipschitz dual of X to characterize those elements of G which are best... Let (X,d) be a real metric linear space, with translation-invariant metric d and C a linear subspace of X. In this paper we use functionals in the Lipschitz dual of X to characterize those elements of G which are best approximations to elements of X.We also give simultaneous characterization of elements of best approximation and also consider elements of ε-approximation. 展开更多
关键词 metric linear space Lipschitz dual best approximation metric projection proximinal set Chebyshev set ε-approximation
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Equilibria of the Abstract Economy under Almost Lower Semi-continuous Assumption 被引量:1
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作者 张玉成 陈福川 《Northeastern Mathematical Journal》 CSCD 2003年第1期26-32,共7页
The purpose of this paper is to make a further study on the abstract economy. Here, for the constraint correspondences we assume that they are almost lower semi-continuous (n-lower semi-continuous), which is weaken th... The purpose of this paper is to make a further study on the abstract economy. Here, for the constraint correspondences we assume that they are almost lower semi-continuous (n-lower semi-continuous), which is weaken than that they are lower semi-continuous. Several equilibria existence theorems are proved. 展开更多
关键词 almost lower semi-continuity ε-approximate selection EQUILIBRIUM
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On the k-sample Behrens-Fisher problem for high-dimensional data 被引量:3
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作者 ZHANG JinTing XU JinFeng 《Science China Mathematics》 SCIE 2009年第6期1285-1304,共20页
For several decades, much attention has been paid to the two-sample Behrens-Fisher (BF) problem which tests the equality of the means or mean vectors of two normal populations with unequal variance/covariance structur... For several decades, much attention has been paid to the two-sample Behrens-Fisher (BF) problem which tests the equality of the means or mean vectors of two normal populations with unequal variance/covariance structures. Little work, however, has been done for the k-sample BF problem for high dimensional data which tests the equality of the mean vectors of several high-dimensional normal populations with unequal covariance structures. In this paper we study this challenging problem via extending the famous Scheffe’s transformation method, which reduces the k-sample BF problem to a one-sample problem. The induced one-sample problem can be easily tested by the classical Hotelling’s T 2 test when the size of the resulting sample is very large relative to its dimensionality. For high dimensional data, however, the dimensionality of the resulting sample is often very large, and even much larger than its sample size, which makes the classical Hotelling’s T 2 test not powerful or not even well defined. To overcome this difficulty, we propose and study an L 2-norm based test. The asymptotic powers of the proposed L 2-norm based test and Hotelling’s T 2 test are derived and theoretically compared. Methods for implementing the L 2-norm based test are described. Simulation studies are conducted to compare the L 2-norm based test and Hotelling’s T 2 test when the latter can be well defined, and to compare the proposed implementation methods for the L 2-norm based test otherwise. The methodologies are motivated and illustrated by a real data example. 展开更多
关键词 χ 2-approximation χ 2-type mixtures high-dimensional data analysis Hotelling’s T 2 test k-sample test L 2-norm based test Primary 62H15 Secondary 62E17 62E20
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One-Sided Exact Boundary Null Controllability of Entropy Solutions to a Class of Hyperbolic Systems of Conservation Laws with Characteristics with Constant Multiplicity
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作者 Lei YU 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2018年第6期947-962,共16页
This paper proves the local exact one-sided boundary null controllability of entropy solutions to a class of hyperbolic systems of conservation laws with characteristics with constant multiplicity. This generalizes th... This paper proves the local exact one-sided boundary null controllability of entropy solutions to a class of hyperbolic systems of conservation laws with characteristics with constant multiplicity. This generalizes the results in [Li, T. and Yu, L., One-sided exact boundary null controllability of entropy solutions to a class of hyperbolic systems of conservation laws, To appear in Journal de Mathematiques Pures et Appliquees, 2016.] for a class of strictly hyperbolic systems of conservation laws. 展开更多
关键词 Characteristics with constant multiplicity One-sided boundary null controllability Semi-global entropy solution ε-approximate front tracking solution
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A PRIMAL-DUAL INTERIOR POINT METHOD FOR PARAMETRIC SEMIDEFINITE PROGRAMMING PROBLEMS
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作者 王哲民 周昆平 黄正海 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2000年第2期171-179,共9页
On the basis of primal-dual approach, we present in this paper an interior point method that gives parametric E-approximate solutions to parametric semi-definite programming problems. The method is finite, and the num... On the basis of primal-dual approach, we present in this paper an interior point method that gives parametric E-approximate solutions to parametric semi-definite programming problems. The method is finite, and the number of its iterations is quasi-polynomially bounded. 展开更多
关键词 Interior-point method semidefinite programming problem ε-approximate solution
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