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多类别学习方法:理论上与启示的比较

Multiclass Learning Approaches: A Theoretical Comparison with Implications
课程网址: http://videolectures.net/machine_daniely_learning/  
主讲教师: Amit Daniely
开课单位: 耶路撒冷希伯来大学
开课时间: 2013-06-14
课程语种: 英语
中文简介:
我们在理论上分析和比较以下五种流行的多类分类方法:One vs. All,All Pairs,基于树的分类器,具有随机生成的代码矩阵的纠错输出代码(ECOC)和Multiclass SVM。在前四种方法中,分类基于二元分类的简化。我们考虑二进制分类器来自一个VC维度d的情况,特别是来自\ reals d的半空间类。我们分析了这些方法的估计误差和近似误差。我们的分析揭示了在不同条件下不同方法的成功与实际相关的有趣结论。我们的证明技术使用VC理论中的工具来分析假设类的\ emph {逼近误差}。这与大多数(如果不是全部)VC理论的先前使用形成鲜明对比,VC理论仅涉及估计误差。
课程简介: We theoretically analyze and compare the following five popular multiclass classification methods: One vs. All, All Pairs, Tree-based classifiers, Error Correcting Output Codes (ECOC) with randomly generated code matrices, and Multiclass SVM. In the first four methods, the classification is based on a reduction to binary classification. We consider the case where the binary classifier comes from a class of VC dimension d, and in particular from the class of halfspaces over \reals d. We analyze both the estimation error and the approximation error of these methods. Our analysis reveals interesting conclusions of practical relevance, regarding the success of the different approaches under various conditions. Our proof technique employs tools from VC theory to analyze the \emph{approximation error} of hypothesis classes. This is in sharp contrast to most, if not all, previous uses of VC theory, which only deal with estimation error.
关 键 词: 分类方法; 代码矩阵; 近似误差
课程来源: 视频讲座网
最后编审: 2019-05-15:cwx
阅读次数: 58