arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2104.01115cs.IRstat.ME
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Web页面嵌套文本建模中的局部和全局主题

Local and Global Topics in Text Modeling of Web Pages Nested in Web Sites

Jason Wang, Robert E. Weiss

摘要:

主题模型是用于分析文本文档集合的流行模型。该模型断言,文件是分布在潜在的主题和潜在的主题分布在词。嵌套文档集合是指文档嵌套在更高层次的结构中,如书籍中的故事、期刊中的文章或网站中的网页。在单个文档集合中,主题是全局的,或者在所有文档中共享。对于嵌套在网站中的网页,主题频率可能会因网站而异。在一个网站中,主题频率几乎肯定会在网页之间变化。主题频率的层次先验模型这种层次结构,并指定一个全球主题分布。网站主题分布围绕全局主题分布而变化,并且网页主题分布围绕网站主题分布而变化。在嵌套的网页集合中,某些主题可能是单个网站所独有的。网页嵌套集合中的局部主题是一个网站所独有的主题。对于美国地方卫生部门网站,对文本的简要检查显示了每个部门特有的地方地理和新闻主题,这些主题在其他部门中不存在。忽略嵌套的主题模型可以识别本地主题,但不将主题标记为本地,也不显式地识别本地主题的网站所有者。对于嵌套在网站内的网页,本地主题模型显式地标记本地主题并标识所属网站。这种识别可用于调整关于全局主题的推断。在美国公共卫生网站数据中,主题覆盖率是在从页面中删除本地主题词后在网站级别定义的。分层局部主题模型可用于识别局部主题,调整关于网站是否覆盖特定健康主题的推断,以及研究健康主题的覆盖程度。

英文摘要:

Topic models are popular models for analyzing a collection of text documents. The models assert that documents are distributions over latent topics and latent topics are distributions over words. A nested document collection is where documents are nested inside a higher order structure such as stories in a book, articles in a journal, or web pages in a web site. In a single collection of documents, topics are global, or shared across all documents. For web pages nested in web sites, topic frequencies likely vary between web sites. Within a web site, topic frequencies almost certainly vary between web pages. A hierarchical prior for topic frequencies models this hierarchical structure and specifies a global topic distribution. Web site topic distributions vary around the global topic distribution and web page topic distributions vary around the web site topic distribution. In a nested collection of web pages, some topics are likely unique to a single web site. Local topics in a nested collection of web pages are topics unique to one web site. For US local health department web sites, brief inspection of the text shows local geographic and news topics specific to each department that are not present in others. Topic models that ignore the nesting may identify local topics, but do not label topics as local nor do they explicitly identify the web site owner of the local topic. For web pages nested inside web sites, local topic models explicitly label local topics and identifies the owning web site. This identification can be used to adjust inferences about global topics. In the US public health web site data, topic coverage is defined at the web site level after removing local topic words from pages. Hierarchical local topic models can be used to identify local topics, adjust inferences about if web sites cover particular health topics, and study how well health topics are covered.

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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