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基于特征向量的多谱线自旋回波串信号参数估计
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作者 朱凯然 何学辉 +2 位作者 靳标 朱文涛 苏涛 《电子学报》 EI CAS CSCD 北大核心 2013年第9期1730-1737,共8页
针对存在加性高斯白噪声多参数变量的多谱线自旋回波串(SpinEcho Train,SET)信号参数估计问题,提出基于特征向量的2-D参数估计方法.将SET信号构造成2-D数据矩阵,按照不同的方式构造Hankel块矩阵束,利用子空间转移不变结构解得特征向量,... 针对存在加性高斯白噪声多参数变量的多谱线自旋回波串(SpinEcho Train,SET)信号参数估计问题,提出基于特征向量的2-D参数估计方法.将SET信号构造成2-D数据矩阵,按照不同的方式构造Hankel块矩阵束,利用子空间转移不变结构解得特征向量,依据特征向量的结构规律获得衰减因子和频率,基于最小二乘方法进一步获得信号幅度估计.该方法具有自动配对的能力,在相对高信噪比以及频率可分辨的情况下能够实现参数的有效估计,且计算复杂度较低.仿真数据结果证明了算法的有效性. 展开更多
关键词 核四极矩共振 自旋回波串 2-D参数估计 特征向量基 子空间转移不变结构
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基于压缩感知的相关性数据填补方法 被引量:1
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作者 任兵 郭艳 +1 位作者 李宁 刘存涛 《计算机科学》 CSCD 北大核心 2023年第7期82-88,共7页
数据缺失现象在数据的采集和传输过程中经常发生,而对数据集中缺失数据的不当填补,会对后续的数据挖掘工作产生不利的影响。为了更有效地对缺失数据集进行填补,针对相关性数据,提出了一种基于压缩感知的缺失数据填补方法。首先,将缺失... 数据缺失现象在数据的采集和传输过程中经常发生,而对数据集中缺失数据的不当填补,会对后续的数据挖掘工作产生不利的影响。为了更有效地对缺失数据集进行填补,针对相关性数据,提出了一种基于压缩感知的缺失数据填补方法。首先,将缺失数据填补问题转化为压缩感知框架下的稀疏向量恢复问题;其次,针对数据的相关性特点构造了专门的稀疏表示基,从而能够更好地实现数据的稀疏化;最后,提出了一种快速迭代加权阈值算法,在传统的快速迭代收缩阈值算法的基础上引入了一种新的加权因子及重启动策略,提高了算法的收敛性能和数据的重构精度。仿真结果表明,所提算法能够高效地填补缺失数据,与传统的快速迭代收缩阈值算法相比,重构成功率和重构速度都得到了提升。同时,在数据稀疏变换效果较差的情况下,所提算法仍然能够完成对缺失数据集的填补,具有更好的鲁棒性。 展开更多
关键词 压缩感知 数据填补 相关性数据 正交特征向量基 迭代加权阈值法
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Multi-modal face parts fusion based on Gabor feature for face recognition 被引量:1
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作者 相燕 《High Technology Letters》 EI CAS 2009年第1期70-74,共5页
A novel face recognition method, which is a fusion of muhi-modal face parts based on Gabor feature (MMP-GF), is proposed in this paper. Firstly, the bare face image detached from the normalized image was convolved w... A novel face recognition method, which is a fusion of muhi-modal face parts based on Gabor feature (MMP-GF), is proposed in this paper. Firstly, the bare face image detached from the normalized image was convolved with a family of Gabor kernels, and then according to the face structure and the key-points locations, the calculated Gabor images were divided into five parts: Gabor face, Gabor eyebrow, Gabor eye, Gabor nose and Gabor mouth. After that multi-modal Gabor features were spatially partitioned into non-overlapping regions and the averages of regions were concatenated to be a low dimension feature vector, whose dimension was further reduced by principal component analysis (PCA). In the decision level fusion, match results respectively calculated based on the five parts were combined according to linear discriminant analysis (LDA) and a normalized matching algorithm was used to improve the performance. Experiments on FERET database show that the proposed MMP-GF method achieves good robustness to the expression and age variations. 展开更多
关键词 Gabor filter multi-modal Gabor features principal component analysis (PCA) linear discriminant analysis (IDA) normalized matching algorithm
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Characteristics of a Terrain-Following Sigma Coordinate 被引量:1
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作者 LI Yi-Yuan WANG Bin WANG Dong-Hai 《Atmospheric and Oceanic Science Letters》 2011年第3期157-161,共5页
This study quantifies the main characteristics of a terrain-following, G-coordinate through mathematical analyses of its covariant and contravariant basis vectors as well as the vertical coordinate of σ. A 3-D schema... This study quantifies the main characteristics of a terrain-following, G-coordinate through mathematical analyses of its covariant and contravariant basis vectors as well as the vertical coordinate of σ. A 3-D schematic of the σ-coordinate in a curvilinear coordinate system is provided in this study. The characteristics of the basis vectors were broken down into their "local vector charac- teristics" and "spatial distribution characteristics", and the exact expressions of the covariant; in addition, the con- travariant basis vectors of the G-coordinate used to eluci- date their detailed characteristics were properly solved. Through rewriting the expression of the vertical coordi- nate of G, a mathematical expression of all the cr-coor- dinate surfaces was found, thereby quantifying the so- called terrain-following characteristics and lack of flexi- bility to adjust the slope variation of G-coordinate sur- faces for the classic definition of G. Finally, an analysis on the range value of the vertical coordinate demonstrated that the general value range of G could be obtained by eliminating the G-coordinate surfaces below the Earth's surface. All these quantitative descriptions of the charac- teristics of G-coordinate were the foundation for improv- ing the G-coordinate or creating a new one. 展开更多
关键词 quantitative description sigma coordinate 3-D schematic basis vectors non-orthogonal
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