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Similarity-Invariant Subspaces and Similarity-Preserving Linear Maps 被引量:4
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作者 Guo Xing JI Hong Ke DU Department of Mathematics, Shaanxi Normal University. Xian 710062. P. R. China 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2002年第3期489-498,共10页
In this paper, the similarity-invariant subspaces of B(H), which is tile Banach algebra of all bounded linear operators on a separable infinite-dimensional Hilbert space H, are completely characterized and the represe... In this paper, the similarity-invariant subspaces of B(H), which is tile Banach algebra of all bounded linear operators on a separable infinite-dimensional Hilbert space H, are completely characterized and the representations of bounded linear maps on B(H) which preserve similarity in both directions are given. 展开更多
关键词 linear operator Similarity-invariant subspace similarity-preserving linear map
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Discontinuous bifurcation and coexistence of attractors in a piecewise linear map with a gap 被引量:5
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作者 屈世显 卢永智 +1 位作者 张林 何大韧 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第12期4418-4423,共6页
Coexistence of attractors with striking characteristics is observed in this work, where a stable period-5 attractor coexists successively with chaotic band-ll, period-6, chaotic band-12 and band-6 attractors. They are... Coexistence of attractors with striking characteristics is observed in this work, where a stable period-5 attractor coexists successively with chaotic band-ll, period-6, chaotic band-12 and band-6 attractors. They are induced by dif- ferent mechanisms due to the interaction between the discontinuity and the non-invertibility. A characteristic boundary collision bifurcation, is observed. The critical conditions are obtained both analytically and numerically. 展开更多
关键词 coexistence of attractors piecewise linear map mapping hole discontinuous bifurcation
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LINEAR DILATATION OF QUASIREGULAR MAPPINGS IN SPACE 被引量:2
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作者 陈克应 《Acta Mathematica Scientia》 SCIE CSCD 2001年第2期213-220,共8页
This paper presents an explicit upper bound for the linear dilatation of K- quasiregular (K-qr) mappings, which improves S. Rickman's [6, P.37] corresponding re- sult for K-qr mappings and generalizes P. Seittenra... This paper presents an explicit upper bound for the linear dilatation of K- quasiregular (K-qr) mappings, which improves S. Rickman's [6, P.37] corresponding re- sult for K-qr mappings and generalizes P. Seittenranta's [7, Theorem 1.5] result for K- quasiconformal (K-qc) maps. 展开更多
关键词 K-qr mapping K-qc map linear dilatation local index MODULUS normal domain
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Noise destroys the coexistence of periodic orbits of a piecewise linear map 被引量:1
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作者 王参军 杨科利 屈世显 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第3期205-208,共4页
The effects of Gaussian white noise and Gaussian colored noise on the periodic orbits of period-5(P-5) and period-6(P-6) in their coexisting domain of a piecewise linear map are investigated numerically.The probab... The effects of Gaussian white noise and Gaussian colored noise on the periodic orbits of period-5(P-5) and period-6(P-6) in their coexisting domain of a piecewise linear map are investigated numerically.The probability densities of some orbits are calculated.When the noise intensity is D = 0.0001,only the orbits of P-5 exist,and the coexisting phenomenon is destroyed.On the other hand,the self-correlation time τ of the colored noise also affects the coexisting phenomenon.When τc〈τ〈τc,only the orbits of P-5 appear,and the stability of the orbits of P-5 is enhanced.However,when τ〉τc(τc and τc are critical values),only the orbits of P-6 exist,and the stability of the P-6 orbits is enhanced greatly.When τ〈τc,the orbits of P-5 and P-6 coexist,but the stability of the P-5 orbits is enhanced and that of P-6 is weakened with τ increasing. 展开更多
关键词 piecewise linear map noise periodic orbit
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Solution of Nonlinear Advection-Diffusion Equations via Linear Fractional Map Type Nonlinear QCA 被引量:1
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作者 Shinji Hamada Hideo Sekino 《Journal of Quantum Information Science》 2016年第4期263-295,共33页
Linear fractional map type (LFMT) nonlinear QCA (NLQCA), one of the simplest reversible NLQCA is studied analytically as well as numerically. Linear advection equation or Time Dependent Schr&ouml;dinger Equation (... Linear fractional map type (LFMT) nonlinear QCA (NLQCA), one of the simplest reversible NLQCA is studied analytically as well as numerically. Linear advection equation or Time Dependent Schr&ouml;dinger Equation (TDSE) is obtained from the continuum limit of linear QCA. Similarly it is found that some nonlinear advection-diffusion equations including inviscid Burgers equation and porous-medium equation are obtained from LFMT NLQCA. 展开更多
关键词 Nonlinear Quantum Cellular Automaton QCA Quantum Walk linear Fractional map Advection-Diffusion Equation Burgers Equation Porous-Medium Equation SOLITON
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ESTIMATE ON THE BLOCH CONSTANT FOR CERTAIN HARMONIC MAPPINGS UNDER A DIFFERENTIAL OPERATOR 被引量:1
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作者 陈洁玲 刘名生 《Acta Mathematica Scientia》 SCIE CSCD 2024年第1期295-310,共16页
In this paper,we first obtain the precise values of the univalent radius and the Bloch constant for harmonic mappings of the formL(f)=zfz-zfz,where f represents normalized harmonic mappings with bounded dilation.Then,... In this paper,we first obtain the precise values of the univalent radius and the Bloch constant for harmonic mappings of the formL(f)=zfz-zfz,where f represents normalized harmonic mappings with bounded dilation.Then,using these results,we present better estimations for the Bloch constants of certain harmonic mappings L(f),where f is a K-quasiregular harmonic or open harmonic.Finally,we establish three versions of BlochLandau type theorem for biharmonic mappings of the form L(f).These results are sharp in some given cases and improve the related results of earlier authors. 展开更多
关键词 Bloch-Landau type theorem Bloch constant linear complex operator harmonic mapping biharmonic mapping UNIVALENT
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Linear-fitting-based similarity coefficient map for tissue dissimilarity analysis in T2^*-w magnetic resonance imaging
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作者 余绍德 伍世宾 +5 位作者 王浩宇 魏新华 陈鑫 潘万龙 Hu Jiani 谢耀钦 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第12期610-615,共6页
Similarity coefficient mapping(SCM) aims to improve the morphological evaluation of T*2weighted magnetic resonance imaging(T*2-w MRI). However, how to interpret the generated SCM map is still pending. Moreover, ... Similarity coefficient mapping(SCM) aims to improve the morphological evaluation of T*2weighted magnetic resonance imaging(T*2-w MRI). However, how to interpret the generated SCM map is still pending. Moreover, is it probable to extract tissue dissimilarity messages based on the theory behind SCM? The primary purpose of this paper is to address these two questions. First, the theory of SCM was interpreted from the perspective of linear fitting. Then, a term was embedded for tissue dissimilarity information. Finally, our method was validated with sixteen human brain image series from multiecho T*2-w MRI. Generated maps were investigated from signal-to-noise ratio(SNR) and perceived visual quality, and then interpreted from intra- and inter-tissue intensity. Experimental results show that both perceptibility of anatomical structures and tissue contrast are improved. More importantly, tissue similarity or dissimilarity can be quantified and cross-validated from pixel intensity analysis. This method benefits image enhancement, tissue classification, malformation detection and morphological evaluation. 展开更多
关键词 T*2-w magnetic resonance imaging similarity coefficient map linear fitting tissue dissimilarity
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Non-linear Invertible Maps that Preserve Staircase Subalgebras
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作者 ZHAO YAN-XIA XIA YU-LING 《Communications in Mathematical Research》 CSCD 2012年第3期265-274,共10页
Let g be the general linear Lie algebra consisting of all n x n matrices over a field F and with the usual bracket operation {x, y} =xy - yx. An invertible map φ : g →g is said to preserve staircase subalgebras if ... Let g be the general linear Lie algebra consisting of all n x n matrices over a field F and with the usual bracket operation {x, y} =xy - yx. An invertible map φ : g →g is said to preserve staircase subalgebras if it maps every staircase subalgebra to some staircase subalgebra of the same dimension. In this paper, we devote to giving an explicit description on the invertible maps on g that preserve staircase subalgebras. 展开更多
关键词 general linear Lie algebra staircase subalgebra non-linear map
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Linear Maps Preserving Idempotency of Products of Matrices on Upper Triangular Matrix Algebras
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作者 QI JING Ji GUO-XING 《Communications in Mathematical Research》 CSCD 2009年第3期253-264,共12页
Let Tn be the algebra of all n × n complex upper triangular matrices. We give the concrete forms of linear injective maps on Tn which preserve the nonzero idempotency of either products of two matrices or triple ... Let Tn be the algebra of all n × n complex upper triangular matrices. We give the concrete forms of linear injective maps on Tn which preserve the nonzero idempotency of either products of two matrices or triple Jordan products of two matrices. 展开更多
关键词 linear map MATRIX IDEMPOTENT product of two matrices triple Jordan product of two matrices
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Dissipative Properties of ω-Order Preserving Partial Contraction Mapping in Semigroup of Linear Operator
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作者 Akinola Yussuff Akinyele Kamilu Rauf +1 位作者 Aasa Moses Adebowale Omosowon Jude Babatunde 《Advances in Pure Mathematics》 2019年第6期544-550,共7页
This paper consists of dissipative properties and results of dissipation on infinitesimal generator of a C0-semigroup of ω-order preserving partial contraction mapping (ω-OCPn) in semigroup of linear operator. The p... This paper consists of dissipative properties and results of dissipation on infinitesimal generator of a C0-semigroup of ω-order preserving partial contraction mapping (ω-OCPn) in semigroup of linear operator. The purpose of this paper is to establish some dissipative properties on ω-OCPn which have been obtained in the various theorems (research results) and were proved. 展开更多
关键词 SEMIGROUP linear OPERATOR DISSIPATIVE OPERATOR CONTRACTION mapping and RESOLVENT
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Galois linear maps and their construction
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作者 Gu Yue Wang Wei Wang Shuanhong 《Journal of Southeast University(English Edition)》 EI CAS 2019年第4期522-526,共5页
The condition of an algebra to be a Hopf algebra or a Hopf(co)quasigroup can be determined by the properties of Galois linear maps.For a bialgebra H,if it is unital and associative as an algebra and counital coassocia... The condition of an algebra to be a Hopf algebra or a Hopf(co)quasigroup can be determined by the properties of Galois linear maps.For a bialgebra H,if it is unital and associative as an algebra and counital coassociative as a coalgebra,then the Galois linear maps T1 and T2 can be defined.For such a bialgebra H,it is a Hopf algebra if and only if T1 is bijective.Moreover,T1^-1 is a right H-module map and a left H-comodule map(similar to T2).On the other hand,for a unital algebra(no need to be associative),and a counital coassociative coalgebra A,if the coproduct and counit are both algebra morphisms,then the sufficient and necessary condition of A to be a Hopf quasigroup is that T1 is bijective,and T1^-1 is left compatible with ΔT1-11^r and right compatible with mT1-1^l at the same time(The properties are similar to T2).Furthermore,as a corollary,the quasigroups case is also considered. 展开更多
关键词 Galois linear map ANTIPODE Hopf algebra Hopf(co)quasigroup
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An Automatic Approach for Satisfying Dose-Volume Constraints in Linear Fluence Map Optimization for IMPT
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作者 Maryam Zaghian Gino Lim +1 位作者 Wei Liu Radhe Mohan 《Journal of Cancer Therapy》 2014年第2期198-207,共10页
Prescriptions for radiation therapy are given in terms of dose-volume constraints (DVCs). Solving the fluence map optimization (FMO) problem while satisfying DVCs often requires a tedious trial-and-error for selecting... Prescriptions for radiation therapy are given in terms of dose-volume constraints (DVCs). Solving the fluence map optimization (FMO) problem while satisfying DVCs often requires a tedious trial-and-error for selecting appropriate dose control parameters on various organs. In this paper, we propose an iterative approach to satisfy DVCs using a multi-objective linear programming (LP) model for solving beamlet intensities. This algorithm, starting from arbitrary initial parameter values, gradually updates the values through an iterative solution process toward optimal solution. This method finds appropriate parameter values through the trade-off between OAR sparing and target coverage to improve the solution. We compared the plan quality and the satisfaction of the DVCs by the proposed algorithm with two nonlinear approaches: a nonlinear FMO model solved by using the L-BFGS algorithm and another approach solved by a commercial treatment planning system (Eclipse 8.9). We retrospectively selected from our institutional database five patients with lung cancer and one patient with prostate cancer for this study. Numerical results show that our approach successfully improved target coverage to meet the DVCs, while trying to keep corresponding OAR DVCs satisfied. The LBFGS algorithm for solving the nonlinear FMO model successfully satisfied the DVCs in three out of five test cases. However, there is no recourse in the nonlinear FMO model for correcting unsatisfied DVCs other than manually changing some parameter values through trial and error to derive a solution that more closely meets the DVC requirements. The LP-based heuristic algorithm outperformed the current treatment planning system in terms of DVC satisfaction. A major strength of the LP-based heuristic approach is that it is not sensitive to the starting condition. 展开更多
关键词 FLUENCE map Optimization (FMO) linear PROGRAMMING (LP) Nonlinear PROGRAMMING (NLP) Dose-Volume Constraint (DVC) Intensity-Modulated Proton Therapy (IMPT)
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An Adaptive Non-Linear Map and Its Application
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作者 YAN Xuefeng 《Wuhan University Journal of Natural Sciences》 CAS 2006年第3期572-576,共5页
A novel adaptive non-linear mapping (ANLM), integrating an adaptive mapping error (AME) with a chaosgenetic algorithm (CGA) including chaotic variable, was proposed to overcome the deficiencies of non-linear map... A novel adaptive non-linear mapping (ANLM), integrating an adaptive mapping error (AME) with a chaosgenetic algorithm (CGA) including chaotic variable, was proposed to overcome the deficiencies of non-linear mapping (NLM). The value of AME weight factor is determined according to the relative deviation square of distance between the two mapping points and the corresponding original objects distance. The larger the relative deviation square between two distances is, the larger the value of the corresponding weight factor is. Due to chaotic mapping operator, the evolutional process of CGA makes the individuals of subgenerations distributed ergodieally in the defined space and circumvents the premature of the individuals of subgenerations. The comparison results demonstrated that the whole performance of CGA is better than that of traditional genetic algorithm. Furthermore, a typical example of mapping eight-dimenslonal olive oil samples onto two-dimensional plane was employed to verify the effectiveness of ANLM. The results showed that the topology-preserving map obtained by ANLM can well represent the classification of original objects and is much better than that obtained by NLM. 展开更多
关键词 adaptive non-linear map topology- preserving mapping error chaotic variable genetic algorithm cluster
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Non-linear Maps on Borel Subalgebras of Simple Lie Algebras Preserving Abelin Ideals
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作者 赵延霞 王登银 《Chinese Quarterly Journal of Mathematics》 CSCD 2012年第4期615-623,共9页
Let g be a complex simple Lie algebra of rank ι, b the standard Borel subalgebra. An invertible map on Ь is said to preserve abelian ideals if it maps each abelian ideal to some such ideal of the same dimension. In ... Let g be a complex simple Lie algebra of rank ι, b the standard Borel subalgebra. An invertible map on Ь is said to preserve abelian ideals if it maps each abelian ideal to some such ideal of the same dimension. In this article, by using some results of Chevalley groups, the theory of root systems and root space decomposition, the author gives an explicit description on such maps of Ь. 展开更多
关键词 simple Lie algebra abelian ideal non-linear map
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Non-Linear Effects in Optical Systems by Lie Algebra and Symplectic Mapping
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作者 Víctor M. Castañ o 《Journal of Modern Physics》 CAS 2022年第11期1314-1323,共10页
The use of signals of different frequencies determines the geometrical deviation with respect to the optical axes of a given beam. This angle can be determined by Sympletic Map (SM), a powerful and simple mathematical... The use of signals of different frequencies determines the geometrical deviation with respect to the optical axes of a given beam. This angle can be determined by Sympletic Map (SM), a powerful and simple mathematical tool for the characterization and construction of images in Geometrical Optics. The Sympletic Map constitutes a Lie Group, with an algebra associated: the Lie Algebra. In general, the SM can be expressed as an infinite series, where each term corresponds to different contributions produced by the optical devices that constitute the optical system (lenses, apertures, bandwidth cutoff, etc.). The level of correction to be performed on the image to recover the original object is clear and controllable by SM. This formalism can be extended easily to physical optics to describe diffraction and interference phenomena. 展开更多
关键词 Symplectic mapping Geometrical Optics Non-linear Effects
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改进模糊聚类语义分割声环境功能区划图
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作者 曾宇 姚琨 秦勤 《噪声与振动控制》 北大核心 2025年第2期210-215,共6页
声环境功能区划多采用地理信息系统进行研究,但公开发布的声环境功能区划方案中的文字和图片无法直接用于地理信息系统分析。首先提出改进模糊C均值聚类超像素方法,对声环境功能区划图进行语义分割以获取声功能区信息。接着采用简单线... 声环境功能区划多采用地理信息系统进行研究,但公开发布的声环境功能区划方案中的文字和图片无法直接用于地理信息系统分析。首先提出改进模糊C均值聚类超像素方法,对声环境功能区划图进行语义分割以获取声功能区信息。接着采用简单线性迭代聚类构建超像素,提取声环境功能区划图特征矩阵,基于K-means++改进模糊C均值聚类算法,语义分割超像素粒化的声环境功能区划图,并以声功能区面积占比计算结果偏差为评价指标,分析超像素尺度对分割结果的影响。然后基于不同图像特征矩阵构建方法和聚类中心初始化方法,使用模糊C均值聚类、高斯混合模型聚类、K-medoids聚类语义分割声环境功能区划图,最后比较不同组合方案的声功能区面积占比计算结果偏差,验证方法的有效性。 展开更多
关键词 声学 声环境功能区划图 彩色图像分割 模糊C均值聚类 简单线性迭代聚类 K-means++算法
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Turbo码Log-MAP译码算法的一种改进算法 被引量:6
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作者 许成谦 林雪红 陈嘉兴 《燕山大学学报》 CAS 2002年第4期286-288,300,共4页
Log-MAP算法是Turbo码译码算法的一种简化算法,本文针对其所存在的缺点提出了一种改进的算法,即用分段的线性函数对校正函数进行拟合。计算机模拟结果表明,应用此算法后可在不影响性能的情况下,既能简化算法过程,又能使硬件的实现变得... Log-MAP算法是Turbo码译码算法的一种简化算法,本文针对其所存在的缺点提出了一种改进的算法,即用分段的线性函数对校正函数进行拟合。计算机模拟结果表明,应用此算法后可在不影响性能的情况下,既能简化算法过程,又能使硬件的实现变得更加容易。 展开更多
关键词 信道编码 TURBO码 LOG-map算法 线性拟合 译码
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ISOMAP-LDA方法用于化工过程故障诊断 被引量:4
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作者 成忠 诸爱士 陈德钊 《化工学报》 EI CAS CSCD 北大核心 2009年第1期122-126,共5页
针对化工连续生产过程的时序性及非线性等特征,提出一种新的基于数据驱动的化工过程故障诊断方法:ISOMAP-LDA。首先实行流形学习算法ISOMAP,在保持量测数据几何结构特性下完成非线性降维,然后基于提取的嵌入变量张成的低维空间,选用线... 针对化工连续生产过程的时序性及非线性等特征,提出一种新的基于数据驱动的化工过程故障诊断方法:ISOMAP-LDA。首先实行流形学习算法ISOMAP,在保持量测数据几何结构特性下完成非线性降维,然后基于提取的嵌入变量张成的低维空间,选用线性判别分析(LDA)构造故障模式类的判别函数,负责各采样个体故障类型的判定。将该方法用于仿真化工Tennessee East man过程的故障诊断,结果表明,ISOMAP-LDA方法不仅拥有较高的故障诊断能力,而且取得采样在低维空间的可视化表示。 展开更多
关键词 流形学习 集成等距特征映射 线性判别分析 故障诊断 Tennessee Eastman过程
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UMTS Turbo码的滑动窗-线性-Log-MAP算法及VLSI设计 被引量:2
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作者 刘小同 陈咏恩 《计算机工程与应用》 CSCD 北大核心 2007年第4期74-78,共5页
讨论UMTS中turbo码的设计,提出采用前向状态度量作为初始化精确值的滑动窗方法和改进的Log-MAP(线性Log-MAP)相结合的算法(称为滑动窗-线性-Log-MAP算法),设计出turbo码的VLSI结构,且在归一化处理时,介绍了一种可节约12.5%存储量的方法... 讨论UMTS中turbo码的设计,提出采用前向状态度量作为初始化精确值的滑动窗方法和改进的Log-MAP(线性Log-MAP)相结合的算法(称为滑动窗-线性-Log-MAP算法),设计出turbo码的VLSI结构,且在归一化处理时,介绍了一种可节约12.5%存储量的方法。FPGA设计结果显示在BER=10-5时,与最优算法Log-MAP相比,性能损失0.2dB,硬件资源节约30%,译码时延小,吞吐量大。 展开更多
关键词 通用无线通信系统 涡轮码 线性对数域最大后验概率译码算法 滑动窗方法 滑动窗线性对敷域最大后验概率译码算法 可编程门阵列
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基于改进ISOMAP算法的图像分类 被引量:3
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作者 魏宪 李元祥 +2 位作者 赵海涛 庹红娅 许鹏 《上海交通大学学报》 EI CAS CSCD 北大核心 2010年第7期911-915,共5页
利用基于邻域的图像欧氏距离寻找最近邻,并用直接线性判别分析方法(Direct LDA)取代多维尺度分析法(MDS),提出一种改进的等距特征映射(ISOMAP)算法(KIMD-ISOMAP)进行降维.人脸图像分类试验表明:KIMD-ISOMAP提高了ISOMAP的分类能力,扩展... 利用基于邻域的图像欧氏距离寻找最近邻,并用直接线性判别分析方法(Direct LDA)取代多维尺度分析法(MDS),提出一种改进的等距特征映射(ISOMAP)算法(KIMD-ISOMAP)进行降维.人脸图像分类试验表明:KIMD-ISOMAP提高了ISOMAP的分类能力,扩展了邻域半径的选取范围,在加高斯噪声和几何形变的情况下,该算法与其他方法相比,表现出较强的鲁棒性. 展开更多
关键词 流形学习 等距特征映射 直接线性判别 图像欧氏距离 降维
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