To find the predual spaces Pα（R^n） of Qα（R^n） is an important motivation in the study of Q spaces. In this article, wavelet methods are used to solve this problem in a constructive way. First, an wavelet tent at...To find the predual spaces Pα（R^n） of Qα（R^n） is an important motivation in the study of Q spaces. In this article, wavelet methods are used to solve this problem in a constructive way. First, an wavelet tent atomic characterization of Pα（Rn） is given, then its usual atomic characterization and Poisson extension characterization are given. Finally, the continuity on Pα of Calderon-Zygmund operators is studied, and the result can be also applied to give the Morrey characterization of Pα（Rn）.展开更多
针对磁共振(magnetic resonance,MR)幅度图像中带有不易去除的与信号相关的莱斯(Rician)噪声问题,利用其复数图像中的实部与虚部所含噪声为不相关的加性高斯白噪声这一特性,代替对幅度图像直接去噪,提出将原始对偶字典学习(predual dict...针对磁共振(magnetic resonance,MR)幅度图像中带有不易去除的与信号相关的莱斯(Rician)噪声问题,利用其复数图像中的实部与虚部所含噪声为不相关的加性高斯白噪声这一特性,代替对幅度图像直接去噪,提出将原始对偶字典学习(predual dictionary learning,PDL)算法用于对MR复数图像的实部与虚部分别进行去噪,然后组合得到幅度图像的方法.经仿真实验和在HT-MRSI50-50(50 mm)1.2 T小动物核磁共振系统中的实际应用,证明所提方法较直接对幅度图像去噪取得更好的效果,在有效去除MR图像噪声的同时能较好地保持图像中的细节.与经典的字典学习算法核奇异值分解(kernel singular value decomposition,K-SVD)相比,PDL算法去噪效果优于K-SVD算法,而运算速度提高约5倍.与经典的基于非局部相似块的三维块匹配滤波(block-matching and 3D filtering,BM3D)算法相比,在噪声水平较低时PDL算法略优于BM3D算法,噪声水平较高时BM3D算法略优于PDL算法,两者总体比较接近.展开更多
In this paper, by using the tent spaces on the Siegel upper half space, which are defined in terms of Choquet integrMs with respect to Hausdorff capacity on the Heisenberg group, the Hardy-Hausdorff spaces on the Heis...In this paper, by using the tent spaces on the Siegel upper half space, which are defined in terms of Choquet integrMs with respect to Hausdorff capacity on the Heisenberg group, the Hardy-Hausdorff spaces on the Heisenberg group are introduced. Then, by applying the properties of the tent spaces on the Siegel upper half space and the Sobolev type spaces on the Heisenberg group, the atomic decomposition of the Hardy-Hausdorff spaces is obtained. Finally, we prove that the predual spaces of Q spaces on the Heisenberg group are the Hardy-Hausdorff spaces.展开更多
Given a normed space X it can be easily proven that every extreme point in Bx＊, the unit ball of X＊, is the restriction of an extreme point in Bx Our purpose is to study when the restrictions of extreme points in B...Given a normed space X it can be easily proven that every extreme point in Bx＊, the unit ball of X＊, is the restriction of an extreme point in Bx Our purpose is to study when the restrictions of extreme points in Bx＊＊＊ are extreme points in Bx＊. Namely, we characterize Ll-preduals satisfying the aforementioned property.展开更多
基金supported by NNSF of China No.10001027, 90104004,10471002973 project of China G1999075105+1 种基金the innovation funds of Wuhan Universitythe subject construction funds of Mathematic and Statistic School, Wuhan University.
文摘To find the predual spaces Pα（R^n） of Qα（R^n） is an important motivation in the study of Q spaces. In this article, wavelet methods are used to solve this problem in a constructive way. First, an wavelet tent atomic characterization of Pα（Rn） is given, then its usual atomic characterization and Poisson extension characterization are given. Finally, the continuity on Pα of Calderon-Zygmund operators is studied, and the result can be also applied to give the Morrey characterization of Pα（Rn）.
文摘针对磁共振(magnetic resonance,MR)幅度图像中带有不易去除的与信号相关的莱斯(Rician)噪声问题,利用其复数图像中的实部与虚部所含噪声为不相关的加性高斯白噪声这一特性,代替对幅度图像直接去噪,提出将原始对偶字典学习(predual dictionary learning,PDL)算法用于对MR复数图像的实部与虚部分别进行去噪,然后组合得到幅度图像的方法.经仿真实验和在HT-MRSI50-50(50 mm)1.2 T小动物核磁共振系统中的实际应用,证明所提方法较直接对幅度图像去噪取得更好的效果,在有效去除MR图像噪声的同时能较好地保持图像中的细节.与经典的字典学习算法核奇异值分解(kernel singular value decomposition,K-SVD)相比,PDL算法去噪效果优于K-SVD算法,而运算速度提高约5倍.与经典的基于非局部相似块的三维块匹配滤波(block-matching and 3D filtering,BM3D)算法相比,在噪声水平较低时PDL算法略优于BM3D算法,噪声水平较高时BM3D算法略优于PDL算法,两者总体比较接近.
基金supported by National Natural Science Foundation of China (Grant No. 11471176)Natural Science Foundation of Shandong Province (Grant No. BS2014SF002)
文摘In this paper, by using the tent spaces on the Siegel upper half space, which are defined in terms of Choquet integrMs with respect to Hausdorff capacity on the Heisenberg group, the Hardy-Hausdorff spaces on the Heisenberg group are introduced. Then, by applying the properties of the tent spaces on the Siegel upper half space and the Sobolev type spaces on the Heisenberg group, the atomic decomposition of the Hardy-Hausdorff spaces is obtained. Finally, we prove that the predual spaces of Q spaces on the Heisenberg group are the Hardy-Hausdorff spaces.
基金Supported by Ministerio de Ciencia e Innovación and Junta de Andalucía Projects (Grant Nos. MTM2009-07498, MTM2010-17687 and FQM-3737)
文摘Given a normed space X it can be easily proven that every extreme point in Bx＊, the unit ball of X＊, is the restriction of an extreme point in Bx Our purpose is to study when the restrictions of extreme points in Bx＊＊＊ are extreme points in Bx＊. Namely, we characterize Ll-preduals satisfying the aforementioned property.
