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BOUNDEDNESS OF STEIN'S SQUARE FUNCTIONS ASSOCIATED TO OPERATORS ON HARDY SPACES 被引量:1
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作者 闫雪芳 《Acta Mathematica Scientia》 SCIE CSCD 2014年第3期891-904,共14页
Let (X, d,μ) be a metric measure space endowed with a metric d and a nonnegative Borel doubling measure μ. Let L be a second order non-negative self-adjoint operator on L^2(X). Assume that the semigroup e^-tL ge... Let (X, d,μ) be a metric measure space endowed with a metric d and a nonnegative Borel doubling measure μ. Let L be a second order non-negative self-adjoint operator on L^2(X). Assume that the semigroup e^-tL generated by L satisfies the Davies-Gaffney estimates. Also, assume that L satisfies Plancherel type estimate. Under these conditions, we show that Stein's square function Gδ(L) arising from Bochner-Riesz means associated to L is bounded from the Hardy spaces HL^p(X) to L^p(X) for all 0 〈 p ≤ 1. 展开更多
关键词 Stein's square function non-negative self-adjoint operator Hardy spaces Davies- Gaffney estimate Plancherel type estimate
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A framework for computer vision-based health monitoring of a truss structure subjected to unknown excitations
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作者 Mariusz Ostrowski Bartlomiej Blachowski +3 位作者 Bartosz Wójcik Mateusz Żarski Piotr Tauzowski Łukasz Jankowski 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2023年第1期1-17,共17页
Computer vision(CV)methods for measurement of structural vibration are less expensive,and their application is more straightforward than methods based on sensors that measure physical quantities at particular points o... Computer vision(CV)methods for measurement of structural vibration are less expensive,and their application is more straightforward than methods based on sensors that measure physical quantities at particular points of a structure.However,CV methods produce significantly more measurement errors.Thus,computer vision-based structural health monitoring(CVSHM)requires appropriate methods of damage assessment that are robust with respect to highly contaminated measurement data.In this paper a complete CVSHM framework is proposed,and three damage assessment methods are tested.The first is the augmented inverse estimate(AIE),proposed by Peng et al.in 2021.This method is designed to work with highly contaminated measurement data,but it fails with a large noise provided by CV measurement.The second method,as proposed in this paper,is based on the AIE,but it introduces a weighting matrix that enhances the conditioning of the problem.The third method,also proposed in this paper,introduces additional constraints in the optimization process;these constraints ensure that the stiffness of structural elements can only decrease.Both proposed methods perform better than the original AIE.The latter of the two proposed methods gives the best results,and it is robust with respect to the selected coefficients,as required by the algorithm. 展开更多
关键词 computer vision structural health monitoring physics-based graphical models augmented inverse estimate model updating non-negative least square method
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加权非负最小二乘光子相关光谱纳米颗粒粒径反演方法 被引量:1
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作者 单良 孔明 《光子学报》 EI CAS CSCD 北大核心 2013年第6期684-687,共4页
为了降低采用光子相关光谱法进行纳米颗粒测量时噪音对颗粒粒径反演结果的影响,提出了一种基于加权非负最小二乘法的光子相关光谱纳米颗粒粒径计算方法.该方法以光子相关光谱自身作为权值,推导出反演算法的离散模型,避免了接近零点的测... 为了降低采用光子相关光谱法进行纳米颗粒测量时噪音对颗粒粒径反演结果的影响,提出了一种基于加权非负最小二乘法的光子相关光谱纳米颗粒粒径计算方法.该方法以光子相关光谱自身作为权值,推导出反演算法的离散模型,避免了接近零点的测量数据波动对测量结果的影响.利用光子相关光谱纳米检测实验平台对90nm、190nm及混合的乳胶颗粒进行实验研究,并与传统非负最小二乘法反演结果进行了对比.60s测量时间的30次实验数据表明:对单峰颗粒群进行反演时,该方法多次测量结果与传统非负最小二乘法结果相近,但是多次重复测量的方差较小,证明该方法重复性较好;对多峰颗粒群进行反演时,该方法反演结果更接近颗粒的真实值,而非负最小二乘法其反演结果与真实值有较大偏离.在不同测量时间的实验数据表明:测量较短的情况下,该方法反演结果方差较小,能在更短的采样时间情况下,获得更准确的测量结果. 展开更多
关键词 光子相关光谱法 非负最小二乘 加权 纳米颗粒粒径
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基于非负最小二乘的矢量阵反卷积波束形成方法 被引量:6
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作者 孙大军 马超 +1 位作者 梅继丹 石文佩 《哈尔滨工程大学学报》 EI CAS CSCD 北大核心 2019年第7期1217-1223,共7页
针对现有反卷积波束形成方法无法直接适用于矢量阵等具有移变点扩散函数阵列的问题,本文给出了一种利用非负最小二乘法进行矢量阵这种移变模型的反卷积求解方法。推导了矢量阵的广义卷积模型,并在常规矢量阵波束输出、矢量阵点扩散函数... 针对现有反卷积波束形成方法无法直接适用于矢量阵等具有移变点扩散函数阵列的问题,本文给出了一种利用非负最小二乘法进行矢量阵这种移变模型的反卷积求解方法。推导了矢量阵的广义卷积模型,并在常规矢量阵波束输出、矢量阵点扩散函数字典、目标函数之间建立差函数方程组,通过最小化差函数的原则来实现对目标函数的求解,从而实现矢量阵反卷积波束形成处理。本文方法同样适用于其他移变模型阵列反卷积求解。对本文方法与传统波束形成、最小方差无畸变响应和多重信号分类方法在主瓣宽度、旁瓣级和稳健性等方面的性能进行了对比分析。结果表明本文方法在存在阵元位置误差情况下具有更窄的主瓣宽度和更低的主旁瓣比。 展开更多
关键词 矢量阵 反卷积波束形成 移变点扩散函数 非负最小二乘 高分辨 稳健性
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Non-negative matrix factorization based modeling and training algorithm for multi-label learning 被引量:2
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作者 Liang SUN Hongwei GE Wenjing KANG 《Frontiers of Computer Science》 SCIE EI CSCD 2019年第6期1243-1254,共12页
Multi-label learning is more complicated than single-label learning since the semantics of the instances are usually overlapped and not identical.The effectiveness of many algorithms often fails when the correlations ... Multi-label learning is more complicated than single-label learning since the semantics of the instances are usually overlapped and not identical.The effectiveness of many algorithms often fails when the correlations in the feature and label space are not fully exploited.To this end,we propose a novel non-negative matrix factorization(NMF)based modeling and training algorithm that learns from both the adjacencies of the instances and the labels of the training set.In the modeling process,a set of generators are constructed,and the associations among generators,instances,and labels are set up,with which the label prediction is conducted.In the training process,the parameters involved in the process of modeling are determined.Specifically,an NMF based algorithm is proposed to determine the associations between generators and instances,and a non-negative least square optimization algorithm is applied to determine the associations between generators and labels.The proposed algorithm fully takes the advantage of smoothness assumption,so that the labels are properly propagated.The experiments were carried out on six set of benchmarks.The results demonstrate the effectiveness of the proposed algorithms. 展开更多
关键词 multi-label learning non-negative least square optimization non-negative matrix factorization smoothness assumption
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