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Necessary and Sufficient Conditions for Consensus in Third Order Multi-Agent Systems 被引量:9
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作者 Chi Huang Guisheng Zhai Gesheng Xu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2018年第6期1044-1053,共10页
We deal with a consensus control problem for a group of third order agents which are networked by digraphs.Assuming that the control input of each agent is constructed based on weighted difference between its states a... We deal with a consensus control problem for a group of third order agents which are networked by digraphs.Assuming that the control input of each agent is constructed based on weighted difference between its states and those of its neighbor agents, we aim to propose an algorithm on computing the weighting coefficients in the control input. The problem is reduced to designing Hurwitz polynomials with real or complex coefficients. We show that by using Hurwitz polynomials with complex coefficients, a necessary and sufficient condition can be obtained for designing the consensus algorithm. Since the condition is both necessary and sufficient, we provide a kind of parametrization for all the weighting coefficients achieving consensus. Moreover, the condition is a natural extension to second order consensus, and is reasonable and practical due to its comparatively decreased computation burden. The result is also extended to the case where communication delay exists in the control input. 展开更多
关键词 Communication delay consensus algorithms graph laplacians Hurwitz polynomials third order multi-agent systems.
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Gaussian kernel operators on white noise functional spaces
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作者 骆顺龙 严加安 《Science China Mathematics》 SCIE 2000年第10期1067-1074,共8页
The Gaussian kernel operators on white noise functional spaces, including second quantization, Fourier-Mehler transform, scaling, renormalization, etc. are studied by means of symbol calculus, and characterized by the... The Gaussian kernel operators on white noise functional spaces, including second quantization, Fourier-Mehler transform, scaling, renormalization, etc. are studied by means of symbol calculus, and characterized by the intertwining relations with annihilation and creation operators. The infinitesimal generators of the Gaussian kernel operators are second order white noise operators of which the number operator and the Gross Laplacian are particular examples. 展开更多
关键词 GAUSSIAN KERNEL OPERATORS SYMBOLS laplacians.
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A Cluster Expansion Free Method for Computing Higher Derivatives of the Free Energy and Estimating the Error between the Finite and Infinite Volume Free Energy
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作者 Assane Lo 《Journal of Applied Mathematics and Physics》 2022年第5期1762-1784,共23页
The theory of phase transitions is one of the branches of statistical physics in which smoothness and continuity play an important role. In fact, phase transitions are characterized mathematically by the degree of non... The theory of phase transitions is one of the branches of statistical physics in which smoothness and continuity play an important role. In fact, phase transitions are characterized mathematically by the degree of non-analyticity of the thermodynamic potentials associated with the given system. In this paper, we propose a method that is not based on cluster expansions for computing the higher derivatives of the free energy and estimating the error between the finite and infinite volume free energy in certain continuum gas models. Our approach is suitable for a direct proof of the analyticity of the pressure or free energy in certain models of Kac-type. The methods known up to now strongly rely on the validity of the cluster expansion. An extension of the method to classical lattice gas models is also discussed. 展开更多
关键词 Witten laplacians ANALYTICITY Free Energy Kac-Models
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Nash Embedding,Shape Operator and Navier-Stokes Equation on a Riemannian Manifold
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作者 Shizan FANG 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2020年第2期237-252,共16页
What is the suitable Laplace operator on vector fields for the Navier-Stokes equation on a Riemannian manifold?In this note,by considering Nash embedding,we will try to elucidate different aspects of different Laplace... What is the suitable Laplace operator on vector fields for the Navier-Stokes equation on a Riemannian manifold?In this note,by considering Nash embedding,we will try to elucidate different aspects of different Laplace operators such as de Rham-Hodge Laplacian as well as Ebin-Marsden’s Laplacian.A probabilistic representation formula for Navier-Stokes equations on a general compact Riemannian manifold is obtained when de Rham-Hodge Laplacian is involved. 展开更多
关键词 NASH EMBEDDING shape operator vector valued laplacians NAVIER-STOKES equations stochastic representation
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The Non-Degeneracy of Harmonic Structures on Planar Sierpinski Gaskets
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作者 Shiping Cao Hua Qiu 《Analysis in Theory and Applications》 CSCD 2020年第4期510-516,共7页
We present a direct and short proof of the non-degeneracy of the harmonic structures on the level-n Sierpinski gaskets for any n≥2,which was conjectured by Hino in[1,2]and confirmed to be true by Tsougkas[8]very rece... We present a direct and short proof of the non-degeneracy of the harmonic structures on the level-n Sierpinski gaskets for any n≥2,which was conjectured by Hino in[1,2]and confirmed to be true by Tsougkas[8]very recently using Tutte’s spring theorem. 展开更多
关键词 Fractal analysis harmonic functions fractal laplacians harmonic structures Sierpinski gaskets.
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Generalized Fourier-Mehler transforms on white noise functional spaces
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作者 Shunlong Luo Jia’an Yan 《Chinese Science Bulletin》 SCIE EI CAS 1998年第16期1321-1325,共5页
A new (non-unitary) representation of the general linear group of white noise space on Hida’s test and distribution spaces is presented. The relevant representative operators are natural generalization of Fourier-Meh... A new (non-unitary) representation of the general linear group of white noise space on Hida’s test and distribution spaces is presented. The relevant representative operators are natural generalization of Fourier-Mehler transforms. 展开更多
关键词 WHITE noise CALCULUS general linear group Fourier-Mehler transforms laplacians.
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基于分数阶拉普拉斯算子解耦的黏声介质地震正演模拟与逆时偏移 被引量:21
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作者 吴玉 符力耘 陈高祥 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2017年第4期1527-1537,共11页
时间域常Q黏声波方程,由于含分数阶时间导数项,数值求解需要大量内存,计算效率低,不利于地震偏移的实施.通过一系列近似,可将该方程简化为介质频散效应和衰减效应解耦的分数阶拉普拉斯算子黏声波方程,数值求解内存需求少,计算效率高.本... 时间域常Q黏声波方程,由于含分数阶时间导数项,数值求解需要大量内存,计算效率低,不利于地震偏移的实施.通过一系列近似,可将该方程简化为介质频散效应和衰减效应解耦的分数阶拉普拉斯算子黏声波方程,数值求解内存需求少,计算效率高.本文采用交错网格有限差分逼近时间导数,改进的伪谱法计算空间导数,PML吸收边界去除边界反射,对该方程进行数值离散和地震正演模拟,开展地震数据的黏声介质逆时偏移,实现波场逆时延拓过程中同时完成频散校正和衰减补偿.改善深层构造的成像精度,数值结果表明,基于分数阶拉普拉斯算子解耦的黏声介质地震正演模拟与逆时偏移可大幅度提高地震模拟计算效率,偏移剖面明显优于常规声波偏移剖面,极大改善深层构造的成像品质. 展开更多
关键词 时间域常Q黏声波方程 分数阶拉普拉斯算子 频散与衰减解耦 黏声介质地震模拟与逆时偏移
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一阶速度-压力常分数阶黏滞声波方程及其数值模拟 被引量:12
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作者 陈汉明 汪燚林 周辉 《石油地球物理勘探》 EI CSCD 北大核心 2020年第2期302-310,I0003,共10页
与传统的整数阶黏滞波动方程相比,分数阶拉普拉斯算子黏滞方程能更准确地匹配目前广泛使用的常Q模型,而且分数阶黏滞波动方程中控制振幅衰减和相位变化的算子是显式分离的,这对于发展稳定的衰减补偿逆时偏移算法至关重要。首先基于时间... 与传统的整数阶黏滞波动方程相比,分数阶拉普拉斯算子黏滞方程能更准确地匹配目前广泛使用的常Q模型,而且分数阶黏滞波动方程中控制振幅衰减和相位变化的算子是显式分离的,这对于发展稳定的衰减补偿逆时偏移算法至关重要。首先基于时间域二阶位移形式的常分数阶拉普拉斯算子黏滞声波方程,推导了一阶速度-压力形式常分数阶拉普拉斯算子黏滞声波方程;为了模拟更加真实的振幅变化信息,在新的黏滞声波方程中考虑了密度空变的影响;为了避免由傅里叶变换的周期性而引入的虚假反射,提出了一种适用于分数阶黏滞声波方程的卷积型完全匹配层(CPML)吸收边界加载方法;最后采用交错网格伪谱法进行数值模拟。均匀介质中数值解与解析解的对比证实了该一阶速度-压力常分数阶黏滞声波方程能准确描述常Q模型,BP盐丘模型的地震波场模拟结果证实了其对复杂介质的适用性。 展开更多
关键词 黏滞声波方程 数值模拟 分数阶拉普拉斯算子 交错网格 伪谱法 完全匹配层
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一些特殊图的无符号Laplacians多项式
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作者 尹君 《江汉大学学报(自然科学版)》 2010年第1期10-12,共3页
用表示有n个顶点的简单图G的邻接矩阵,表示图G的度矩阵.图G的无符号矩阵为S=A+D.本文给出了一些特殊图的无符号矩阵和特征多项式.
关键词 无符号laplacians多项式 特殊图
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基于改进谱聚类和交叉标注的多人员指纹定位方法 被引量:2
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作者 黄蕾 刘婷 +1 位作者 刘真真 徐志明 《煤炭学报》 EI CAS CSCD 北大核心 2018年第S2期663-671,共9页
在目前矿井集中式人员定位方法精度与运行效率较低的背景下,文中分析了分布式矿井定位系统模型构建的必要性与算法要求,将现今较为先进的机器学习谱聚类算法使用图论的方法进行了算法改进,分析了运用切比雪夫多项式估计方法完成图谱滤... 在目前矿井集中式人员定位方法精度与运行效率较低的背景下,文中分析了分布式矿井定位系统模型构建的必要性与算法要求,将现今较为先进的机器学习谱聚类算法使用图论的方法进行了算法改进,分析了运用切比雪夫多项式估计方法完成图谱滤波器与特征值的运算简化过程,构建了一套与矿井定位要求相匹配的改进谱聚类算法。结合矿井具体定位应用过程,分析了传统定位指纹数据收集方式的局限性,提出多人员定位指纹数据交叉标注技术,在数据采集与算法运行两个层面提高了矿井人员定位系统的整体精度,从根本上改进了定位时效性。 展开更多
关键词 改进谱聚类 交叉标注技术 分布式矿井定位系统 拉普拉斯图矩阵 机器学习
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上半空间高次分数阶Laplace方程解的不存在性 被引量:2
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作者 李冬艳 陈文雄 《纺织高校基础科学学报》 CAS 2017年第1期18-22,共5页
研究上半空间中带Navier条件的高次分数阶Laplace方程正解的不存在性.借助迭代法,建立高次分数阶方程的狭窄区域原理;然后结合移动平面法,证明具有Navier条件的高次分数阶方程正解的不存在性.
关键词 高次分数阶Laplace方程 Navier条件 狭窄区域极值原理 解不存在性
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三分谢尔宾斯基垫片上的标准拉普拉斯算子 被引量:1
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作者 王丽 《江苏理工学院学报》 2014年第6期13-17,共5页
写这篇文章的目的,就是推导出三分谢尔宾斯基垫片(SG3)上的标准拉普拉斯算子。第一部分介绍了三分谢尔宾斯基垫片(分形集)。第二部分依据文献[2]的理论,首先定义了V0上的拉普拉斯算子D,D∈LA(V0);又在{Vm}m≥0构建了一个自相似拉普拉斯... 写这篇文章的目的,就是推导出三分谢尔宾斯基垫片(SG3)上的标准拉普拉斯算子。第一部分介绍了三分谢尔宾斯基垫片(分形集)。第二部分依据文献[2]的理论,首先定义了V0上的拉普拉斯算子D,D∈LA(V0);又在{Vm}m≥0构建了一个自相似拉普拉斯算子序列Hm;然后又给出了调和结构的定义,求出了三分谢尔宾斯基垫片的调和结构。最后依据了文献[4]的理论,采用了由简到繁的方法,推算出了SG3上的逐点标准拉普拉斯算子,它是SG3上图拉普拉斯算子的极限。 展开更多
关键词 三分谢尔宾斯基垫片 迭代函数系 相容序列 调和结构 标准拉普拉斯算子
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三分谢尔宾斯基垫片上的调和函数与双调和函数的算法
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作者 王丽 《江苏理工学院学报》 2014年第4期59-63,共5页
在这篇文章中,我们首先介绍了三分谢尔宾斯基垫片和标准拉普拉斯算子;其次,我们推导出了三分谢尔宾斯基垫片上调和函数与双调和函数的算法。图的顶点上这些函数的算法最后得出了预垫片,也就是近似三分谢尔宾斯基垫片。
关键词 算法 标准拉普拉斯算子 调和函数 双调和函数
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L^2-SPACES AND SUB-LAPLACIANS ON HOMO GENEOUS GROUPS
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作者 孙利民 《Analysis in Theory and Applications》 1992年第1期59-74,共16页
In this paper,we introduce a special class of nilpotent Lie groups defined by hermitian maps,which includes all the groups of affine holomorphic automorphisims of Siegel domains of type Ⅱ,in particular,the Heisenberg... In this paper,we introduce a special class of nilpotent Lie groups defined by hermitian maps,which includes all the groups of affine holomorphic automorphisims of Siegel domains of type Ⅱ,in particular,the Heisenberg group.And we study harmonic analysis on these groups as spectral theory of the associated Sub-Laplacian instead of the group representation theory in usual way. 展开更多
关键词 exp L~2-SPACES AND SUB-laplacians ON HOMO GENEOUS GROUPS
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空间观测图像宇宙线噪声去除算法
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作者 张健 沈同圣 +1 位作者 娄树理 任建存 《光电工程》 CAS CSCD 北大核心 2014年第5期12-18,共7页
空间观测图像容易受到宇宙线噪声的干扰。本文提出一种空间观测图像宇宙线噪声去除算法。首先利用Top-hat变换抑制观测图像的杂散光,处理之后的观测图像背景均匀,直方图的近Gaussian形状得以恢复。然后利用形态学运算和中值滤波相结合... 空间观测图像容易受到宇宙线噪声的干扰。本文提出一种空间观测图像宇宙线噪声去除算法。首先利用Top-hat变换抑制观测图像的杂散光,处理之后的观测图像背景均匀,直方图的近Gaussian形状得以恢复。然后利用形态学运算和中值滤波相结合的方法排除高亮过饱和恒星的干扰。最后利用Laplacians边缘检测算法检测宇宙线噪声像素,并利用邻域最小值滤波的方法对宇宙线像素的灰度值进行插值处理。实验结果表明,本文方法在不产生误检测的前提下,检测概率超过90%,综合性能优于本文中提到的其它三种宇宙线噪声去除方法。 展开更多
关键词 宇宙线 TOP-HAT变换 形态学运算 中值滤波 laplacians算子
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图的无符号拉普拉斯谱半径的一个新上界
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作者 张士洋 叶淼林 《安庆师范学院学报(自然科学版)》 2010年第4期43-44,56,共3页
设图G是一个有n个顶点、m条边的简单图,Q(G)为图G的无符号拉普拉斯矩阵,本文利用图的度序列平方和上界,给出了简单图无符号拉普拉斯谱半径的一个新的上界。
关键词 度序列的平方和 无符号拉普拉斯矩阵 谱半径上界
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A Robust and Fast Non-Local Means Algorithm for Image Denoising 被引量:30
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作者 刘艳丽 王进 +2 位作者 陈曦 郭延文 彭群生 《Journal of Computer Science & Technology》 SCIE EI CSCD 2008年第2期270-279,共10页
In the paper, we propose a robust and fast image denoising method. The approach integrates both Non- Local means algorithm and Laplacian Pyramid. Given an image to be denoised, we first decompose it into Laplacian pyr... In the paper, we propose a robust and fast image denoising method. The approach integrates both Non- Local means algorithm and Laplacian Pyramid. Given an image to be denoised, we first decompose it into Laplacian pyramid. Exploiting the redundancy property of Laplacian pyramid, we then perform non-local means on every level image of Laplacian pyramid. Essentially, we use the similarity of image features in Laplacian pyramid to act as weight to denoise image. Since the features extracted in Laplacian pyramid are localized in spatial position and scale, they are much more able to describe image, and computing the similarity between them is more reasonable and more robust. Also, based on the efficient Summed Square Image (SSI) scheme and Fast Fourier Transform (FFT), we present an accelerating algorithm to break the bottleneck of non-local means algorithm - similarity computation of compare windows. After speedup, our algorithm is fifty times faster than original non-local means algorithm. Experiments demonstrated the effectiveness of our algorithm. 展开更多
关键词 image denoising non-local means laplacian pyramid summed square image FFT
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基于微分图像自相关的离焦模糊图像盲复原 被引量:23
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作者 赵琳 金伟其 +1 位作者 陈翼男 苏秉华 《光学学报》 EI CAS CSCD 北大核心 2008年第9期1703-1709,共7页
针对离焦模糊图像的盲复原算法的研究具有重要的实际意义和实用价值。根据光学离焦成像模型,研究提出了一种基于微分图像自相关的离焦模糊图像超分辨力盲复原算法,即首先采用拉普拉斯算子对离焦模糊图像进行二阶微分并求微分图像的自相... 针对离焦模糊图像的盲复原算法的研究具有重要的实际意义和实用价值。根据光学离焦成像模型,研究提出了一种基于微分图像自相关的离焦模糊图像超分辨力盲复原算法,即首先采用拉普拉斯算子对离焦模糊图像进行二阶微分并求微分图像的自相关,然后从自相关结果所包含的信息中确定离焦模糊半径,最后以离焦模糊模型结合MPMAP超分辨力复原算法对离焦模糊图像进行盲复原。实验证明:算法能够以较高的精度估计出离焦模糊半径并实现离焦模糊图像的盲复原,该算法较其它同类算法在减少计算过程中需要考虑的各类因素的同时也减少了计算量,提高了结果精度,依靠超分辨力复原算法获取更多的复原图像信息,已在实际刑侦和物证鉴定的离焦模糊图像判读和鉴定中获得成功应用。 展开更多
关键词 图像复原 离焦模糊图像 自相关 拉普拉斯算子 超分辨力
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基于拉普拉斯算子的彩色图像锐化处理 被引量:16
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作者 吴海波 刘钊 《电脑开发与应用》 2008年第9期27-28,共2页
彩色图像增强过程中,对图像进行锐化处理是一个重要环节。介绍了图像锐化处理的概念和拉普拉斯算子的算法原理;重点阐述了一种基于拉普拉斯算子,在C#.NET中构造功能函数并借助模板取样测试原理实现彩色图像锐化处理的方法。实践证明,BMP... 彩色图像增强过程中,对图像进行锐化处理是一个重要环节。介绍了图像锐化处理的概念和拉普拉斯算子的算法原理;重点阐述了一种基于拉普拉斯算子,在C#.NET中构造功能函数并借助模板取样测试原理实现彩色图像锐化处理的方法。实践证明,BMP、JPEG格式的图像使用该方法锐化后的效果良好。 展开更多
关键词 图像锐化 拉普拉斯算子 模板取样
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Terrorist Networks, Network Energy and Node Removal: A New Measure of Centrality Based on Laplacian Energy 被引量:16
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作者 Xingqin Qi Robert D. Duval +6 位作者 Kyle Christensen Edgar Fuller Arian Spahiu Qin Wu Yezhou Wu Wenliang Tang Cunquan Zhang 《Social Networking》 2013年第1期19-31,共13页
In this work we propose a centrality measure for networks, which we refer to as Laplacian centrality, that provides a general framework for the centrality of a vertex based on the idea that the importance (or centrali... In this work we propose a centrality measure for networks, which we refer to as Laplacian centrality, that provides a general framework for the centrality of a vertex based on the idea that the importance (or centrality) of a vertex is related to the ability of the network to respond to the deactivation or removal of that vertex from the network. In particular, the Laplacian centrality of a vertex is defined as the relative drop of Laplacian energy caused by the deactivation of this vertex. The Laplacian energy of network G with?n?vertices is defined as , where ?is the eigenvalue of the Laplacian matrix of G. Other dynamics based measures such as that of Masuda and Kori and PageRank compute the importance of a node by analyzing the way paths pass through a node while our measure captures this information as well as the way these paths are “redistributed” when the node is deleted. The validity and robustness of this new measure are illustrated on two different terrorist social network data sets and 84 networks in James Moody’s Add Health in school friendship nomination data, and is compared with other standard centrality measures. 展开更多
关键词 NETWORK CENTRALITY laplacian ENERGY 9/11 HIJACKING Bali BOMBING Terrorism
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