Short introduction to Vector Space Model (VSM) In information retrieval or text mining, the term frequency - inverse document frequency also called tf-idf, is
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X. Liu, and W. Croft. SIGIR '04: Proceedings of the 27th annual international ACM SIGIR conference on Research and development in information retrieval, page 186--193. New York, NY, USA, ACM, (2004)
W. Xu, X. Liu, and Y. Gong. SIGIR '03: Proceedings of the 26th annual international ACM SIGIR conference on Research and development in informaion retrieval, page 267--273. New York, NY, USA, ACM, (2003)
N. Slonim, and N. Tishby. SIGIR '00: Proceedings of the 23rd annual international ACM SIGIR conference on Research and development in information retrieval, page 208--215. New York, NY, USA, ACM, (2000)
N. Slonim, and N. Tishby. SIGIR '00: Proceedings of the 23rd annual international ACM SIGIR conference on Research and development in information retrieval, page 208--215. New York, NY, USA, ACM, (2000)