The proposed model takes into account the subtopic structures of documents . it first splits the documents into text segments with texttiling and calculates the similarities for different pairs of text segments in the documents . lastly the overall similarity between the documents is returned by combining the similarities of different pairs of text segments with optimal matching method 该模型首先采用texttiling技术将文档分割成能代表子主题的文本块，然后计算两个文档中不同文本块之间的相似度，最后通过图论中的最优匹配方法综合文本块之间的相似度得到两个文档之间的总体相似度。
