关键词: 改进TF-IDF, 关键词抽取, 信息熵, 离散度, 特征融合

Abstract:

Under the national policy the guidance to rule the country by law, it is an inevitable trend to combine the field of artificial intelligence, such as NLP（Natural Language Processing） and IR（Information Retrieve）, with the need to rule of law. In this paper, through the research of keyword extraction method for judicial documents, the purpose is to provide accurate and comprehensive intelligent assistance for judicial service workers to improve work efficiency. This paper proposes an improved TF-IDF algorithm, named Improved Algorithm for Keyword Extraction in Forensics（IAKEF）, targeting to the disadvantages of traditional keyword extraction methods, according to the multiple factors such as part of speech, length, word span, position and document category, based on the TextRank algorithm of graph model, introducing the concepts of information entropy, dispersion degree and fusion features. The algorithm mainly solves the problems of traditional algorithms for semantic neglect of words and distribution of information among classes or a class inner, so that the features from text can be selected more effectively. With the experiments and the comparison of algorithms, the improvement effect is analyzed and verified, the experimental results show that the improved algorithm has a significant improvement in accuracy, recalling-rate and F1-Measure compared with the traditional algorithm.

Key words: improved TF-IDF, keyword extraction, information entropy, dispersion, feature fusion