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高维矩阵的凸松弛与估计

Convex Relaxation and Estimation of High-Dimensional Matrices
课程网址: http://videolectures.net/aistats2011_wainwright_convex/  
主讲教师: Martin J. Wainwright
开课单位: 普林斯顿大学
开课时间: 信息不详。欢迎您在右侧留言补充。
课程语种: 英语
中文简介:
在统计和机器学习中,经常出现需要从噪声观测中估计高维矩阵的问题。实例包括降维方法(如主成分和正则相关)、协同过滤和矩阵补全(如Netflix等推荐系统)、多元回归、时间序列模型估计和图形模型学习。当样本量小于矩阵维数时,所有这些问题都是不适定的,需要某种类型的结构才能得到有趣的结果。近年来,基于核范数和其他类型的凸矩阵调节器的松弛技术得到了广泛的应用。通过将一类广泛的问题框定为矩阵回归的特殊情况,我们提出了一个单一的理论结果,保证了这种凸松弛的准确性。我们的一般结果可以被专门用来得到各种非渐近界,其中包括矩阵补全、矩阵压缩和矩阵分解的噪声形式的急剧率。在所有这些情况下,信息理论方法可以用来证明我们的速率是最小最优的,因此不能被任何算法大幅度改进,不管计算复杂度。
课程简介: Problems that require estimating high-dimensional matrices from noisy observations arise frequently in statistics and machine learning. Examples include dimensionality reduction methods (e.g., principal components and canonical correlation), collaborative filtering and matrix completion (e.g., Netflix and other recommender systems), multivariate regression, estimation of time-series models, and graphical model learning. When the sample size is less than the matrix dimensions, all of these problems are ill-posed, so that some type of structure is required in order to obtain interesting results. In recent years, relaxations based on the nuclear norm and other types of convex matrix regularizers have become popular. By framing a broad class of problems as special cases of matrix regression, we present a single theoretical result that provides guarantees on the accuracy of such convex relaxations. Our general result can be specialized to obtain various non-asymptotic bounds, among them sharp rates for noisy forms of matrix completion, matrix compression, and matrix decomposition. In all of these cases, information-theoretic methods can be used to show that our rates are minimax-optimal, and thus cannot be substantially improved upon by any algorithm, regardless of computational complexity.
关 键 词: 高维矩阵; 凸松弛; 估计
课程来源: 视频讲座网
最后编审: 2019-10-30:cwx
阅读次数: 36