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自仿射信号分维数估计算法的改进 被引量:3
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作者 姜建东 陈进 屈梁生 《信号处理》 CSCD 1999年第1期54-59,67,共7页
对现有的各种分维数算法进行了比较,同时,针对文献中所给出的结构函数法的缺陷提出了改进措施。分析结果表明,采用改进结构函数法计算的结果具有偏差小、精度高、计算量小等优越性。
关键词 自仿射信号 分维数估计 算法 信号分析
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基于分形布朗运动模型信号分维数估计
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作者 陈斌 毛峡 《电子测量技术》 2002年第4期7-8,共2页
电子元器件的噪声,通信网络中的数据流量等信号具有分形特性,分形维数是此类信号分形特性的量度。文中研究了基于分形布朗运动模型的分形维数估计的不同方法,对于此类信号的仿真及分类提供了有效方法。
关键词 分形布朗运动模型 信号 分维数估计 小波变换
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基于图像分形维数估计的最小盒计数法的研究 被引量:7
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作者 尹贤龙 《电气应用》 北大核心 2006年第9期93-96,106,共5页
通过对估计图像分维数的差分盒计数法的深入研究,发现差分盒计数法估计覆盖分形曲面的盒子数可能出现“空盒子”被计数,从而导致盒子数偏多而生产冗余,使得差分盒计数法估计数字图像的分维数不具有普遍适用性,特别是对那些曲面变化较剧... 通过对估计图像分维数的差分盒计数法的深入研究,发现差分盒计数法估计覆盖分形曲面的盒子数可能出现“空盒子”被计数,从而导致盒子数偏多而生产冗余,使得差分盒计数法估计数字图像的分维数不具有普遍适用性,特别是对那些曲面变化较剧烈的分形图像更为突出。为此,提出了具有普适性的有效估计图像分维数的最小盒计数法和采用逐段搜索法寻找分形无标度区的方法,并通过对XLPE电力电缆局部放电灰度图像和Brodatz纹理图像分维数估计的实例分析进行了验证,验证表明,基于分维估计的最小盒计数法可以用来对电力电缆局部放电信号灰度图像进行模式识别。 展开更多
关键词 分维数估计 最小盒计 差分盒计 局部放电 灰度图像
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Estimation of Data Transfer Routes Fractal Dimension in Large Scale Networks
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作者 Yuriy Danik Yuriy Kulakov +1 位作者 Vladimir Vorotnikov Igor Gumenyuk 《Journal of Mathematics and System Science》 2016年第1期38-45,共8页
The article is devoted to the evaluation of fractal properties of routing data in computer large scale networks. Implemented the study of percolation network topological structures of large dimension and made their tr... The article is devoted to the evaluation of fractal properties of routing data in computer large scale networks. Implemented the study of percolation network topological structures of large dimension and made their transformation into fractal macrostructure. An example of calculating the fractal dimension of the data path for the boundary of the phase transition between the states of network connectivity. The dependence of the fractal dimension of the percolation cluster on the size of the square δ-cover and conductivity value network of large dimension. It is shown that for the value of the fractal dimension of the route dc ≈ 1.5, network has a stable dynamics of development and size of clusters are optimized with respect to the current load on the network. 展开更多
关键词 large scale network percolation cluster fractal dimension ROUTING
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ON A HYPER HILBERT TRANSFORM 被引量:1
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作者 CHENJIECHENG DINGYONO FANDASHAN 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2003年第4期475-484,共10页
The authors define the directional hyper Hilbert transform and give ita mixed norm estimate. The similar conclusions for the directional fractional integral of one dimension are also obtained in this paper. As an appl... The authors define the directional hyper Hilbert transform and give ita mixed norm estimate. The similar conclusions for the directional fractional integral of one dimension are also obtained in this paper. As an application of the above results, the authors give the Lp-boundedness for a class of the hyper singular integrals and the fractional integrals with variable kernel. Moreover, as another application of the above results, the authors prove the dimension free estimate for the hyper Riesz transform. This is an extension of the related result obtained by Stein. 展开更多
关键词 Hyper Hilbert transform Sobolev spaces Dimension free estimate Singular integral Practional integral
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Asymptotic properties of Lasso in high-dimensional partially linear models 被引量:3
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作者 MA Chi HUANG Jian 《Science China Mathematics》 SCIE CSCD 2016年第4期769-788,共20页
We study the properties of the Lasso in the high-dimensional partially linear model where the number of variables in the linear part can be greater than the sample size.We use truncated series expansion based on polyn... We study the properties of the Lasso in the high-dimensional partially linear model where the number of variables in the linear part can be greater than the sample size.We use truncated series expansion based on polynomial splines to approximate the nonparametric component in this model.Under a sparsity assumption on the regression coefficients of the linear component and some regularity conditions,we derive the oracle inequalities for the prediction risk and the estimation error.We also provide sufficient conditions under which the Lasso estimator is selection consistent for the variables in the linear part of the model.In addition,we derive the rate of convergence of the estimator of the nonparametric function.We conduct simulation studies to evaluate the finite sample performance of variable selection and nonparametric function estimation. 展开更多
关键词 Lasso irrepresentable condition restricted eigenvalue semiparametric models sparsity
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Maximal Dimension of Invariant Subspaces to Systems of Nonlinear Evolution Equations 被引量:13
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作者 Shoufeng SHEN Changzheng QU +1 位作者 Yongyang JIN Lina JI 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2012年第2期161-178,共18页
In this paper, the dimension of invariant subspaces admitted by nonlinear sys- tems is estimated under certain conditions. It is shown that if the two-component nonlinear vector differential operator F = (F1, F2) wi... In this paper, the dimension of invariant subspaces admitted by nonlinear sys- tems is estimated under certain conditions. It is shown that if the two-component nonlinear vector differential operator F = (F1, F2) with orders {k1, k2} (k1≥ k2) preserves the invariant subspace Wn1^1× Wn2^2 (n1 ≥ n2), then n1 - n2 ≤ k2, n1 ≤2(k1 + k2) + 1, where Wnq^q is the space generated by solutions of a linear ordinary differential equation of order nq (q = 1, 2). Several examples including the (1+1)-dimensional diffusion system and Ito's type, Drinfel'd-Sokolov-Wilson's type and Whitham-Broer-Kaup's type equations are presented to illustrate the result. Furthermore, the estimate of dimension for m-component nonlinear systems is also given. 展开更多
关键词 Invariant subspace Nonlinear PDEs Exact solution SYMMETRY Dynamical system
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