arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1502.02277cs.IRcs.CL
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多主题文档词频规范化的改进及其在语言建模中的应用

Improving Term Frequency Normalization for Multi-topical Documents, and Application to Language Modeling Approaches

POSTECH(浦项科技大学);KISTI(韩国科学技术信息研究院)

Seung-Hoon Na, In-Su Kang, Jong-Hyeok Lee

摘要:

由于文档的长度不同,词频规范化是一个严重的问题。通常,文档变长是由于两个不同的原因-冗长和多主题。首先,冗长意味着同一主题被与该主题相关的术语重复提及,因此术语频率比概括良好的术语频率更高。第二,多主题性表明一份文件对多个主题进行了广泛的讨论,而不是单一主题。虽然这些文件的特点,应该有不同的处理,所有以前的方法的词频规范化忽略了这些差异,并使用了一个简化的长度驱动的方法,减少的词频只有一个文件的长度,造成不合理的惩罚。为了解决这个问题,我们提出了一种新的TF归一化方法,这是一种部分公理化的方法。首先,我们制定了两个正式的约束,检索模型应满足的文件具有冗长和多主题的特点,分别。然后,我们修改语言建模方法,以更好地满足这两个约束,并推导出新的平滑方法。实验结果表明,该方法显著提高了关键字查询的准确率,并大大提高了详细查询的平均精度。

英文摘要:

Term frequency normalization is a serious issue since lengths of documents are various. Generally, documents become long due to two different reasons - verbosity and multi-topicality. First, verbosity means that the same topic is repeatedly mentioned by terms related to the topic, so that term frequency is more increased than the well-summarized one. Second, multi-topicality indicates that a document has a broad discussion of multi-topics, rather than single topic. Although these document characteristics should be differently handled, all previous methods of term frequency normalization have ignored these differences and have used a simplified length-driven approach which decreases the term frequency by only the length of a document, causing an unreasonable penalization. To attack this problem, we propose a novel TF normalization method which is a type of partially-axiomatic approach. We first formulate two formal constraints that the retrieval model should satisfy for documents having verbose and multi-topicality characteristic, respectively. Then, we modify language modeling approaches to better satisfy these two constraints, and derive novel smoothing methods. Experimental results show that the proposed method increases significantly the precision for keyword queries, and substantially improves MAP (Mean Average Precision) for verbose queries.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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