This article mainly researches about the impassion of DI and LFHW terms on classification,the construction of LFHW term sets and new approaches to term weighting.

• 该文重点研究了特征的类间、类内分布,以及低频高权特征对分类的影响,并在此基础上提出了低频高权特征集的构造方法及特征权重的新算法,同时将该算法推广到多层次分类体系。