Improving text categorization using domain knowledge

In this paper, we mainly study and propose an approach to improve document classification using domain knowledge. First we introduce a domain knowledge dictionary NEUKD, and propose two models which use domain knowledge as textual features for text categorization. The first one is BOTW model which uses domain associated terms and conventional words as textual features. The other one is BOF model which uses domain features as textual features. But due to limitation of size of domain knowledge dictionary, we study and use a machine learning technique to solve the problem, and propose a BOL model which could be considered as the extended version of BOF model. In the comparison experiments, we consider naive Bayes system based on BOW model as baseline system. Comparison experimental results of naive Bayes systems based on those four models (BOW, BOTW, BOF and BOL) show that domain knowledge is very useful for improving text categorization. BOTW model performs better than BOW model, and BOL and BOF models perform better than BOW model in small number of features cases. Through learning new features using machine learning technique, BOL model performs better than BOF model.