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压缩传感中的相变现象

Phase transitions phenomenon in Compressed Sensing
课程网址: http://videolectures.net/smls09_tanner_ptpics/  
主讲教师: Jared Tanner
开课单位: 牛津大学
开课时间: 2009-05-06
课程语种: 英语
中文简介:
压缩传感重建算法对于大问题尺寸通常表现为零阶相变现象,其中存在一个问题尺寸域,成功恢复的概率为绝对概率,存在一个问题尺寸域,恢复失败的概率为绝对概率。这一现象的数学基础将概述为1美元的正则化和非负可行性点区域。这两个实例都使用了相关几何概率事件的大偏差分析。这些结果给出了压缩传感应用中所需样本数量的精确条件。对于以下算法,也将给出高斯随机矩阵的限制等距特性所暗示的相变的下限:$\ell^q$—对于$q\ in(0,1]$、cosamp、子空间跟踪和迭代硬阈值的正则化。
课程简介: Compressed Sensing reconstruction algorithms typically exhibit a zeroth-order phase transition phenomenon for large problem sizes, where there is a domain of problem sizes for which successful recovery occurs with overwhelming probability, and there is a domain of problem sizes for which recovery failure occurs with overwhelming probability. The mathematics underlying this phenomenon will be outlined for $\ell1$ regularization and non-negative feasibility point regions. Both instances employ a large deviation analysis of the associated geometric probability event. These results give precise if and only if conditions on the number of samples needed in Compressed Sensing applications. Lower bounds on the phase transitions implied by the Restricted Isometry Property for Gaussian random matrices will also be presented for the following algorithms: $\ell^q$-regularization for $q\in (0,1]$, CoSaMP, Subspace Pursuit, and Iterated Hard Thresholding.
关 键 词: 计算机科学; 机器学习; 压缩传感
课程来源: 视频讲座网
最后编审: 2020-05-30:张荧(课程编辑志愿者)
阅读次数: 92