Automatic recognition of topic transition for newspaper articles and application to document summary

本文对报刊文章的自动摘要进行了研究，主要研究内容如下：(1)从大规模语料库中建立主题模板，并利用该主题模板正确抽取目标文章的后续文章。将提取出的后续文章归类到主题簇中。(2)对每个主题簇进行了总结，并根据主题簇之间的联系对后续文章进行了整体的总结。实验结果表明，该方法能够在大型语料库(通过话题检测和跟踪的语料库和《每日新闻》的文章)(研究论文4，5)上高精度地抽取后续文章。我们提出了一种从日文报纸(3，4)中识别同义词对的方法。对于同义词的识别，我们比较了Lin的方法和Hindle的方法，发现Lin的方法比Hindle的方法更适用于日文文档，并在此基础上提出了一种日文文档的同义词识别方法。此外，我们还利用自动提取的同义词对和报纸文章的标题进行了句子抽取的实验(研究论文1，2)。该方法首先从报刊文章中提取出报刊文章标题中的同义词，然后利用提取的结果进行句子抽取。实验结果表明，识别同义词对句子提取有一定的帮助。

In this study, we paid attention to the automatic summary for the newspaper articles.The following was researched as a first step to summarize multi-documents precisely.(1)A subject template is made from the large-scale corpus, and we extract the subsequent articles of a target article using that subject template correctly. The extracted subsequent articles are classified in the subject cluster.(2)Every subject cluster is summarized, and the whole of the subsequent articles is summarized in consideration of a connection between the clusters.Regarding (1), we proposed a method for topic tracking using subject templates and machine learning (support vector machines). And also, we showed that our methods can extract subsequent articles with high accuracy using large corpus (the corpus by Topic detection and Tracking and articles of Mainichi Shimbun newspaper) (research paper 4,5).Regarding (2), we found that we have to extract synonyms of each word for multi-document summarization. We proposed a method to identify synonym pairs from Japanese newspaper (3,4). For identifying synonyms, we compared Lin's method with Hindle's method and we found Lin's method is better than Hindle's method for Japanese documents.We proposed a method which is based on Lin's method for Japanese documents. Moreover, we performed some experiments of sentence extraction using automatically extracted synonym pairs and title of newspaper article (research paper 1,2). The method is as the following, firstly from newspaper articles we extracted synonyms of words in titles of newspaper articles using the proposed method which is based on Lin's method, then we performed sentence extraction using the results. The results show that identifying synonyms is useful for sentence extraction.