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Using lexical chains for keyword extraction. Presenter : Jian-Ren Chen Authors : Gonenc Ercan , Ilyas Cicekli * 2007.IPM. Outlines. Motivation Objectives Methodology Experiments Conclusions Comments. Motivation.
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Using lexical chains for keyword extraction Presenter : Jian-Ren ChenAuthors : GonencErcan, IlyasCicekli *2007.IPM
Outlines • Motivation • Objectives • Methodology • Experiments • Conclusions • Comments
Motivation It is a hard and time consuming task to assign keywords to documents. The automatic keyphrase extraction algorithms are limited with phrases that appear in the text.
Objectives • We present a keyword extraction method such that it uses the features based on lexical chains in the selection of keywords for a text.
Methodology • first occurrence position • frequency • last occurrence position
Methodology – Lexical chains • WordNet- synonym、hyponym/hypernym • more than one relationship • up to 3 levels of depth • identify nouns • only consider individual words
Methodology – lexical chains • Lexical chain score of a word: • Direct Lexical chain score of a word: • Lexical chain span score of a word: • Direct lexical chain span score of a word: 59 (=7 · 7 + 10) 28 (=4 · 7)
Experiments - Datasets - extract 1, 5, 10, 15 keywords for each document
Experiments • Lexical chain score of a word: • Direct Lexical chain score of a word: • Lexical chain span score of a word: • Direct lexical chain span score of a word:
Conclusions According to the results that are obtained, the lexical chain features improve the precision significantly in the keyword extraction process.
Comments • Advantages • Lexical chains will more consider the semantic relationships • Applications • keyword extraction