The traditionally TC methods are based on bag of words which has two main flaws: one is less category information, and the other is high dimensionality which causes data sparse.

• 传统的文本分类方法都是用词作为特征来构建的,而用词来表示文本的特征虽然简单直观,但有其固有的局限性,主要有包含的类别信息太少,维数过高从而造成数据稀疏等两个问题。