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通过模块功能结构稀疏诱导规范

Structured sparsity-inducing norms through submodular functions
课程网址: http://videolectures.net/nips2010_bach_ssi/  
主讲教师: Francis R. Bach
开课单位: 法国国家信息与自动化研究所
开课时间: 2011-01-12
课程语种: 英语
中文简介:
监督学习的稀疏方法旨在从尽可能少的变量中寻找良好的线性预测因子,即支持的基数很小。这种组合选择问题通常通过用凸包络(最紧凸下界)代替基数函数而变成凸优化问题,在这种情况下是l1范数。本文研究的集函数比基数更为一般,它可以包含许多应用中常见的先验知识或结构约束:即,对于非衰减子模集函数,可以从其Lovasz扩展(子模中的一个常用工具)中得到相应的凸包络。R分析。这定义了一系列多面体规范,为此我们提供通用算法工具(子梯度和近端运算符)和理论结果(支持恢复或高维推理的条件)。通过选择特定的子模函数,我们可以对已知的规范给出新的解释,例如基于秩统计的规范或具有潜在重叠组的分组规范;我们还定义了新的规范,特别是可以用作监督学习的非因式先验的规范。
课程简介: Sparse methods for supervised learning aim at finding good linear predictors from as few variables as possible, i.e., with small cardinality of their supports. This combinatorial selection problem is often turned into a convex optimization problem by replacing the cardinality function by its convex envelope (tightest convex lower bound), in this case the L1-norm. In this paper, we investigate more general set-functions than the cardinality, that may incorporate prior knowledge or structural constraints which are common in many applications: namely, we show that for nondecreasing submodular set-functions, the corresponding convex envelope can be obtained from its Lovasz extension, a common tool in submodular analysis. This defines a family of polyhedral norms, for which we provide generic algorithmic tools (subgradients and proximal operators) and theoretical results (conditions for support recovery or high-dimensional inference). By selecting specific submodular functions, we can give a new interpretation to known norms, such as those based on rank-statistics or grouped norms with potentially overlapping groups; we also define new norms, in particular ones that can be used as non-factorial priors for supervised learning.
关 键 词: 计算机科学; 机器学习; 监督学习
课程来源: 视频讲座网
最后编审: 2020-06-03:王淑红(课程编辑志愿者)
阅读次数: 168