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Spectrality of a class of self-affine measures with decomposable digit sets 被引量:7
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作者 LI JianLin 《Science China Mathematics》 SCIE 2012年第6期1229-1242,共14页
The self-affine measure associated with an expanding matrix and a finite digit set is uniquely determined by the self-affine identity with equal weight. The spectral and non-spectral problems on the self- affine measu... The self-affine measure associated with an expanding matrix and a finite digit set is uniquely determined by the self-affine identity with equal weight. The spectral and non-spectral problems on the self- affine measures have some surprising connections with a number of areas in mathematics, and have been received much attention in recent years. In the present paper, we shall determine the spectrality and non-spectrality of a class of self-aiffine measures with decomposable digit sets. We present a method to deal with such case, and clarify the spectrality and non-spectrality of a class of self-affine measures by applying this method. 展开更多
关键词 iterated function system self-affine measure orthogonal exponentials spectrality digit set
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ON THE ITERATED ORDER OF MEROMORPHIC SOLUTIONS OF HIGHER ORDER LINEAR DIFFERENTIAL EQUATIONS 被引量:3
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作者 CaoTingbin ChenZongxuan +1 位作者 ZhengXiumin TuJin 《Annals of Differential Equations》 2005年第2期111-122,共12页
In this paper, we investigate complex homogeneous and non-homogeneous higher order linear differential equations with meromorphic coefficients. We obtain several results concerning the iterated order of meromorphic so... In this paper, we investigate complex homogeneous and non-homogeneous higher order linear differential equations with meromorphic coefficients. We obtain several results concerning the iterated order of meromorphic solutions, and the iterated convergence exponent of the zeros of meromorphic solutions. 展开更多
关键词 linear differential equation meromorphic function iterated order iterated convergence exponent
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奇点附近高阶齐次线性微分方程解及其任意阶导数的值分布
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作者 龚攀 涂金 徐洪焱 《应用数学》 北大核心 2024年第3期618-628,共11页
本文研究高阶齐次线性微分方程解及其任意阶导数的值分布,其中系数在奇异点附近解析或者亚纯.得到该方程解的增长性的一些估计,并推广和改进了相关定理.
关键词 奇点 迭代级 小函数 解析函数
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激光切割表面形貌的分形插值模拟分析 被引量:5
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作者 赵林 耿雷 齐立涛 《机械设计与制造》 北大核心 2014年第7期123-126,共4页
以实测激光切割表面轮廓高度数据为基础,获取不同采样间距的插值基础数据,应用三维表面分型插值算法,对激光切割表面形貌进行分形插值模拟,分析垂直比例因子和采样间距对模拟精度的影响。结果表明:模拟表面形貌与实测轮廓相似程度随着... 以实测激光切割表面轮廓高度数据为基础,获取不同采样间距的插值基础数据,应用三维表面分型插值算法,对激光切割表面形貌进行分形插值模拟,分析垂直比例因子和采样间距对模拟精度的影响。结果表明:模拟表面形貌与实测轮廓相似程度随着垂直比例因子hi,j的减小而提高,当hi,j小于某一特定值时,表面形貌特征无明显变化;随着采样间距Lc的减小,分形插值表面所包含的微观形貌信息越来越多,逐渐接近真实的激光切割表面形貌,且相对于实测表面的D和Ra值波动均不大,说明分形插值表面具有很高的模拟精度。因此,利用分形插值模拟表面可以对激光切割表面进行有效的切割质量评价和形貌特征分析。 展开更多
关键词 分形插值 激光切割 迭代函数 表面形貌 垂直比例因子
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A necessary and sufficient condition for the finite μM,D-orthogonality 被引量:5
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作者 LI JianLin 《Science China Mathematics》 SCIE CSCD 2015年第12期2541-2548,共8页
The self-affine measure μM,D associated with an expanding matrix M ∈ Mn(Z) and a finite digit set D ? Znis uniquely determined by the self-affine identity with equal weight. The set of orthogonal exponential functio... The self-affine measure μM,D associated with an expanding matrix M ∈ Mn(Z) and a finite digit set D ? Znis uniquely determined by the self-affine identity with equal weight. The set of orthogonal exponential functions E(Λ) := {e2πiλ,x : λ∈Λ} in the Hilbert space L2(μM,D) is simply called μM,D-orthogonal exponentials. We consider in this paper the finiteness of μM,D-orthogonality. A necessary and sufficient condition is obtained for the set E(Λ) to be a finite μM,D-orthogonal exponentials. The research here is closely connected with the non-spectrality of self-affine measures. 展开更多
关键词 iterated function system self-affine measure non-spectrality digit set
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Activation Functions Effect on Fractal Coding Using Neural Networks
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作者 Rashad A.Al-Jawfi 《Intelligent Automation & Soft Computing》 SCIE 2023年第4期957-965,共9页
Activation functions play an essential role in converting the output of the artificial neural network into nonlinear results,since without this nonlinearity,the results of the network will be less accurate.Nonlinearity... Activation functions play an essential role in converting the output of the artificial neural network into nonlinear results,since without this nonlinearity,the results of the network will be less accurate.Nonlinearity is the mission of all nonlinear functions,except for polynomials.The activation function must be dif-ferentiable for backpropagation learning.This study’s objective is to determine the best activation functions for the approximation of each fractal image.Different results have been attained using Matlab and Visual Basic programs,which indi-cate that the bounded function is more helpful than other functions.The non-lin-earity of the activation function is important when using neural networks for coding fractal images because the coefficients of the Iterated Function System are different according to the different types of fractals.The most commonly cho-sen activation function is the sigmoidal function,which produces a positive value.Other functions,such as tansh or arctan,whose values can be positive or negative depending on the network input,tend to train neural networks faster.The coding speed of the fractal image is different depending on the appropriate activation function chosen for each fractal shape.In this paper,we have provided the appro-priate activation functions for each type of system of iterated functions that help the network to identify the transactions of the system. 展开更多
关键词 Activation function fractal coding iterated function system
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ON COMPACTNESS FOR ITERATED COMMUTATORS 被引量:1
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作者 刘永民 于燕燕 《Acta Mathematica Scientia》 SCIE CSCD 2011年第2期491-500,共10页
The authors study the iterated commutators on the weighted Bergman spaces A2(φ), and prove that Cnh is compact on A2(φ) if and only if h ∈ B0.
关键词 Weighted Bergman space iterated commutator normal function littleBloch function COMPACTNESS
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ON THE COMPLEX OSCILLATION OF HIGHER ORDER LINEAR DIFFERENTIAL EQUATIONS WITH MEROMORPHIC COEFFICIENTS 被引量:1
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作者 Tingbin CAO Hongxun YI 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2007年第1期135-148,共14页
In this paper, we investigate the complex oscillation of higher order homogenous and non- homogeneous linear differential equations with meromorphic coefficients of iterated order, and obtain some results which improv... In this paper, we investigate the complex oscillation of higher order homogenous and non- homogeneous linear differential equations with meromorphic coefficients of iterated order, and obtain some results which improve and extend those given by Z. X. Chen, L. Kinnunen, etc. 展开更多
关键词 EXPONENT iterated convergence iterated order linear differential equation meromorphic function.
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DISTRIBUTION FREE LAWS OF THEITERATED LOGARITHM FOR KERNELESTIMATOR OF REGRESSION FUNCTIONBASED ON DIRECTIONAL DATADISTRIBUTION FREE LAWS OF THEITERATED LOGARITHM FOR KERNELESTIMATOR OF REGRESSION FUNCTIONBASED ON DIRECTIONAL DATA 被引量:2
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作者 WANGXIAOMING ZHAOLINCHENG WUYAOHUA 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2000年第4期489-498,共10页
The authors derive laws of the iterated logarithm for kernel estimator of regression function based on directional data. The results are distribution free in the sense that they are true for all distributions of desig... The authors derive laws of the iterated logarithm for kernel estimator of regression function based on directional data. The results are distribution free in the sense that they are true for all distributions of design variable. 展开更多
关键词 Directional data Laws of the iterated logrithm Regression function kernel estimator Strong convergence rates
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Analysis of a class of spectral pair conditions 被引量:2
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作者 LI JianLin 《Science China Mathematics》 SCIE 2011年第10期2099-2110,共12页
For an expanding integer matrix M ∈ Mn(Z) and two finite digit sets D, S C Z^n with O∈ D ∩ S, we shall investigate and study the possible conditions on the spectral pair (μM,D,A(M, S)) associated with the it... For an expanding integer matrix M ∈ Mn(Z) and two finite digit sets D, S C Z^n with O∈ D ∩ S, we shall investigate and study the possible conditions on the spectral pair (μM,D,A(M, S)) associated with the iterated function systems {Фd(X) = M^-1(x + d)}d∈D and {φs(x) = M^*x + s}s∈S in the case when |D|= |S| = | det(M)|. Under the condition that (M^-1D, S) is a compatible pair, we obtain a series of necessary and sufficient conditions for (μM,D, A(M, S)) to be a spectral pair. These conditions include how to characterize the invariant sets A(M, S) and T(M, D) such that A(M, S) = Zn and μL(T(M, D)) = 1 which play an important role in the number system research and in the construction of Haar-type orthogonal wavelet basis respectively. 展开更多
关键词 iterated function system self-affine measure spectral pair compatible pair digit set
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A Note on Invariant Sets
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作者 瞿成勤 苏维宜 许勇 《Northeastern Mathematical Journal》 CSCD 2000年第4期451-453,共3页
The lower bound of Hausdorff dimension of the invariant set is given.
关键词 invariant set Hausdorff dimension iterated function
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A LAW OF THE ITERATED LOGARITHM FOR RANDOM WINDOW-WIDTH KERNEL ESTIMATOR OF A NONPARAMETRIC REGRESSION FUNCTION
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作者 洪圣岩 《Systems Science and Mathematical Sciences》 SCIE EI CSCD 1990年第4期356-363,共8页
In this paper we study the estimation of the regression function.We establish a law ofthe iterated logarithm for the random window-width kernel estimator and,as an application,fora nearest neighbor estimator.These res... In this paper we study the estimation of the regression function.We establish a law ofthe iterated logarithm for the random window-width kernel estimator and,as an application,fora nearest neighbor estimator.These results give sharp pointwise rates of strong consistency ofthese estimators. 展开更多
关键词 Regression function RANDOM window-width kernel ESTIMATOR nearest neighbor ESTIMATOR law of the iterated LOGARITHM
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Hausdorff dimension of self-similar sets with overlaps
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作者 DENG QiRong John HARDING HU TianYou 《Science China Mathematics》 SCIE 2009年第1期119-128,共10页
We provide a simple formula to compute the Hausdorff dimension of the attractor of an overlapping iterated function system of contractive similarities satisfying a certain collection of assumptions. This formula is ob... We provide a simple formula to compute the Hausdorff dimension of the attractor of an overlapping iterated function system of contractive similarities satisfying a certain collection of assumptions. This formula is obtained by associating a non-overlapping infinite iterated function system to an iterated function system satisfying our assumptions and using the results of Moran to compute the Hausdorff dimension of the attractor of this infinite iterated function system, thus showing that the Hausforff dimension of the attractor of this infinite iterated function system agrees with that of the attractor of the original iterated function system. Our methods are applicable to some iterated function systems that do not satisfy the finite type condition recently introduced by Ngai and Wang. 展开更多
关键词 Hausdorff dimension iterated function system SELF-SIMILARITY 28A78 28A80
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方程求解中迭代法的使用
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作者 陈桂秀 《青海师范大学学报(自然科学版)》 2009年第1期16-18,共3页
本文针对方程求解中常用的迭代方法,主要介绍了收敛迭代公式的构造过程,并通过举例加以说明.
关键词 迭代法 收敛迭代公式 迭代函数
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Particle filter based on iterated importance density function and parallel resampling 被引量:1
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作者 武勇 王俊 曹运合 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第9期3427-3439,共13页
The design, analysis and parallel implementation of particle filter(PF) were investigated. Firstly, to tackle the particle degeneracy problem in the PF, an iterated importance density function(IIDF) was proposed, wher... The design, analysis and parallel implementation of particle filter(PF) were investigated. Firstly, to tackle the particle degeneracy problem in the PF, an iterated importance density function(IIDF) was proposed, where a new term associating with the current measurement information(CMI) was introduced into the expression of the sampled particles. Through the repeated use of the least squares estimate, the CMI can be integrated into the sampling stage in an iterative manner, conducing to the greatly improved sampling quality. By running the IIDF, an iterated PF(IPF) can be obtained. Subsequently, a parallel resampling(PR) was proposed for the purpose of parallel implementation of IPF, whose main idea was the same as systematic resampling(SR) but performed differently. The PR directly used the integral part of the product of the particle weight and particle number as the number of times that a particle was replicated, and it simultaneously eliminated the particles with the smallest weights, which are the two key differences from the SR. The detailed implementation procedures on the graphics processing unit of IPF based on the PR were presented at last. The performance of the IPF, PR and their parallel implementations are illustrated via one-dimensional numerical simulation and practical application of passive radar target tracking. 展开更多
关键词 particle filter iterated importance density function least squares estimate parallel resampling graphics processing unit
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分形图像的压缩与还原 被引量:1
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作者 闫新惠 童小念 《中南民族大学学报(自然科学版)》 CAS 2003年第4期61-63,共3页
通过对分形图像压缩理论的分析 ,用 C语言开发了压缩静态图像数据的软件 .对软件编码的具体方法、实现步骤和设计过程作了详细的讨论 ,并给出了测试结果 .结果表明 :分形思想提高了图像压缩比和编码、解码的速度 ,特别适于一次压缩。
关键词 分形 图像压缩 迭代函数
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SHACAL-2算法的研究与改进 被引量:1
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作者 时阳阳 黄玉划 陈帮春 《计算机应用研究》 CSCD 北大核心 2013年第8期2520-2522,2526,共4页
SHACAL-2是2003年当选的四个欧洲分组密码标准算法中分组长度和密钥长度均为最长的算法。为了加快SHACAL-2扩散和混乱,对其算法进行两方面的修改:一方面修改密钥扩展函数,可以避免初始密钥在全为0而扩展后依旧全为0,并且提高了加密的效... SHACAL-2是2003年当选的四个欧洲分组密码标准算法中分组长度和密钥长度均为最长的算法。为了加快SHACAL-2扩散和混乱,对其算法进行两方面的修改:一方面修改密钥扩展函数,可以避免初始密钥在全为0而扩展后依旧全为0,并且提高了加密的效率;另一方面修改迭代函数,使得上一轮的所有消息分组能同时影响到下一轮的两个消息分组。依赖性测试表明,改进后算法比改进前提前1轮开始满足完备性、雪崩效应和严格雪崩准则;模差分攻击分析表明,该算法的18步差分攻击的时间复杂度由O(214)提高到O(227)。改进方案提高了算法的效率和安全性。 展开更多
关键词 SHACAL-2 迭代函数 密钥扩展 依赖性测试 模差分攻击
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基于遗传算法的分形艺术图案生成方法 被引量:1
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作者 李杰 刘弘 《山东大学学报(工学版)》 CAS 2008年第6期33-36,共4页
将遗传算法与分形艺术设计相结合,提出一种基于遗传算法的分形图案生成方法.这种方法通过二叉树结构表示分形图案的迭代函数,并对树型结构表示的迭代函数进行遗传操作,产生新的后代.为更快、更好地满足用户提出的设计需求提供了有利帮助... 将遗传算法与分形艺术设计相结合,提出一种基于遗传算法的分形图案生成方法.这种方法通过二叉树结构表示分形图案的迭代函数,并对树型结构表示的迭代函数进行遗传操作,产生新的后代.为更快、更好地满足用户提出的设计需求提供了有利帮助.通过实验验证其算法的可行性. 展开更多
关键词 遗传算法 分形 二叉树 迭代函数
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图象的分形编码及解码
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作者 罗伟斌 王天珍 陈建华 《武汉汽车工业大学学报》 CAS 1996年第3期52-56,共5页
介绍用分形理论对数字图象进行编码压缩的原理,并提出用抖动法改善图象质量的方法。从自行开发的系统上对多幅图象编码实验的结果看来,压缩比远远高于一般编码的压缩比,经过抖动处理后恢复的图象方块效应得以改善、视觉效果得以增强。
关键词 分形编码 压缩映射 迭代函数 数字图像 解码
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Upper Bound and Lower Bound Estimate of Monotone Increasing Fractal Function
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作者 MA Guan-zhong YUAN Gui-xia CUI Zhen-wen 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2008年第2期188-194,共7页
Mass distribution principle is one of important tools in studying Hausdorff dimension and Hausdorff measure. In this paper we will give a numerical approximate method of upper bound and lower bound of mass distributio... Mass distribution principle is one of important tools in studying Hausdorff dimension and Hausdorff measure. In this paper we will give a numerical approximate method of upper bound and lower bound of mass distribution function f(x)(it is a monotone increasing fractal function) and its some applications. 展开更多
关键词 FRACTAL mass distribution function iterated function system piecewise anti- Bezier curve
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