摘要： TF-IDF（term frequency–inverse document frequency）是一种统计方法，用于评估一个词对N篇文章或一个语料库中其中一篇文章的重要性。一个词在一篇文章中出现的次数并不能表明该词的重要性，例如“我们”，“的”这种常见词，我们需要TF-IDF统计方法。词的重要度随着它在一篇文章中出现的次数成正比增加，但同时会随着它在N篇文章（文章集合）中出现的频率成反比下降。在一篇给定的文章中，词频(term frequency, TF)指的是该文章中某个词出现的次数除以该文章的总词数。逆向文档频率（inverse document frequency, IDF）是一个词普 阅读全文

摘要： The Term Count ModelDemystifying Term Vector CalculationsDr. E. GarciaMi Islita.comEmail| Last Update: 10/27/06Article 2 of the seriesTerm Vector Theory and Keyword WeightsTopicsBackgroundTerm CountsDemystifying Term VectorsComputing Vector MagnitudesComputing Dot ProductsComputing Cosine ValuesA Li 阅读全文

摘要： The Classic Vector Space ModelDescription, Advantages and Limitations of the Classic Vector Space ModelDr. E. GarciaMi Islita.comEmail| Last Update: 10/27/06Article 3 of the seriesTerm Vector Theory and Keyword WeightsTopicsGlobal InformationSelf-Similarity ElementsVector Space ExampleSimilarity Ana 阅读全文

摘要： Term Vector Theory and Keyword WeightsAn Introductory Series on Term Vector Theory for Information Retrieval Students and Search Engine MarketersDr. E. GarciaMi Islita.comEmail| Last Update: 10/27/06Article 1 of the seriesTerm Vector Theory and Keyword WeightsTopicsSalton's Vector Space ModelLoc 阅读全文