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文本分类综述 王  斌 中国科学院计算技术研究所 2002 年 12 月
报告内容 ,[object Object],[object Object],[object Object],[object Object]
文本分类的定义和应用
定义 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
应用 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
文本分类的方法
人工方法和自动方法 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
文本分类的过程 文本表示 训练过程 分类过程 训练文本 统计 统计量 特征表示 学习 分类器 新文本 문서 特征表示 类别
特征抽取 (feature extraction) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
文本表示 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Term 的粒度 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
权重计算方法 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
特征选择 (1) ,[object Object],[object Object],[object Object],[object Object]
特征选择 (2) ,[object Object],[object Object]
特征选择 (3) ,[object Object],[object Object],A B C D t ~t c ~c
特征选择 (4) ,[object Object],[object Object],[object Object],[object Object]
特征选择方法的性能比较 (1)
特征选择方法的性能比较 (2)
特征选择方法的性能比较 (3) YangYi-ming
特征重构 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
自动文本分类方法 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Rocchio 方法 ,[object Object],[object Object],[object Object],类 C 中心向量的权重 训练样本中正例个数 文档向量的权重
Naïve Bayes 参数计算 Bayes 公式
kNN 方法 ,[object Object],新文本 k=1, A 类 k=4 , B 类 k=10 , B 类 带权重计算,计算权重和最大的类。 k 常取 3 或者 5 。
决策树方法 ,[object Object],[object Object],[object Object],[object Object],[object Object]
Decision Rule Learning ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],( 粗糙集 )RoughSet  逻辑表达式 (AQ11 算法 ) 学习到如下规则
The Widrow-Hoff Classifier Online Learning 类 c 向量的第 j 个分量 x i 的第 j 个分量 Learning Rate Target Value ( 0 or 1)
Neural Network . . . . . c 1 c 2 c n …… Input Layer Hidden Layer Output Layer Backpropagation
支持向量机 Support Vector Machine Support Vector Optimal  Separating  Hyperplane
基于投票的方法 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
文本分类的评估指标
分类方法的评估 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],d c 标 NO b a 标 YES 错误 真正对的
其他分类方法 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
参考文献
文献及其他资源 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
谢谢! [email_address] http://mtgroup.ict.ac.cn/~wangbin

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