Outline Vector Space Model (VSM) Latent Semantic Model (LSI) ·Language Model(LM) CCF-ADL at Zhengzhou University, 2 June25-27,2010
Outline • Vector Space Model (VSM) • Latent Semantic Model (LSI) • Language Model (LM) 2 CCF-ADL at Zhengzhou University, June 25-27, 2010
Simple flow of retrieval process Information Need Text Objects 2 Representation Representation Query Indexed Objects Comparison Evaluation /Feedback Retrieved Objects CCF-ADL at Zhengzhou University June25-27,2010
CCF -ADL at Zhengzhou University, June 25 -27, 2010 3
文件E)编辑(E)查看)历史（⑤）书签但)工具（①）帮助仙) http://www.google.com/search?hl-en&newwindow=-18q-latent+semantictindexing&aq-0e&oq Google 4 in Zob..James Mcc-.Chengxian..图百度搜索_Gmail-nb.Conferenc..web Base. Pregel 如何修改p.laten.…区 Web Images Videos Maps News Shopping Gmail more kyhhdm@gmail.com|Web History I Settings Google latent semantic indexing Search Advanced Search weh田Show options. Results 1-10 of about 129,000 for latent semantic indexing.(0.31 seco Latent semantic indexing-Wikipedia,the free encyclopedia Latent Semantic Indexing(LSI)is an indexing and retrieval method that uses a mathematical technique called Singular Value Decomposition (SVD)to identify... Relevance Feedback Benefits of LSI-LSI Timeline-Mathematics of LSI en.wikipedia.org/wiki/Latent_semantic_indexing-Cached-Similar- Query Expansion Latent semantic analysis-Wikipedia,the free encyclopedia CO:2-9.http://Isi.research.telcordia.com/Isi/papers/JASIS90.pdf.Original article where the model was first exposed.Michael Berry.S.T.Dumais,.. Occurrence matrix-Applications-Rank lowering-Derivation en.wikipedia.org/wiki/Latent_semantic_analysis-Cached-Similar- Google Semantically Related Words Latent Semantic Indexing .. Google recently strongly promoted the semantic relationships of words in their algorithm. www.seobook.com/archives/000657.shtml-Cached-Similar-x Latent Semantic Indexing Latent semantic indexing adds an important step to the document indexing process.In addition to recording which keywords a document contains,.. www.seobook.com/lsi/lsa_definition.htm-Cached Similar- LSI-Latent Semantic Indexing Web Site January 12,2006 podcast interview of Michael W.Berry discussing LSI on the Good Karma Show hosted by Greg Niland (aka GoodROl)at WebmasterRadio.fm... ww.cs.utk.edu-lsi/-Cached-Similar-⊙图☒ Laterit Semantic Indexingrsity, 完成tne25-27,2010
Relevance Feedback Query Expansion CCF-ADL at Zhengzhou University, June 25-27, 2010 4
Vector Space Model
Vector Space Model
Documents as vectors Di D2 D3 Da Ds Do 中国 4.1 0.0 3.7 5.9 3.1 0.0 文化 4.5 4.5 0 0 11.6 0 日本 0 3.5 2.9 0 2.1 3.9 留学生 0 3.1 5.1 12.8 0 0 教育 2.9 0 0 2.2 0 0 北京 7.1 0 0 0 4.4 3.8 每一个文档j能够被看作一个向量，每个term是一个维 度，取值为log-scaled tf.idf So we have a vector space -terms are axes docs live in this space -高维空间：即使作stemming,.may have20,000+dimensions 6
Documents as vectors • 每一个文档 j 能够被看作一个向量，每个term 是一个维 度，取值为log-scaled tf.idf • So we have a vector space – terms are axes – docs live in this space – 高维空间：即使作stemming, may have 20,000+ dimensions D1 D2 D3 D4 D5 D6 … 中国 4.1 0.0 3.7 5.9 3.1 0.0 文化 4.5 4.5 0 0 11.6 0 日本 0 3.5 2.9 0 2.1 3.9 留学生 0 3.1 5.1 12.8 0 0 教育 2.9 0 0 2.2 0 0 北京 7.1 0 0 0 4.4 3.8 … 6