IR-part2

1541 simple example using classicaon for ad hoc ir

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Unformatted text preview: 11 gossip 2 0 6 wuthering 0 0 38 Term frequencies (counts) Note: To simplify this example, we don’t do idf weigh*ng. Introduc)on to Informa)on Retrieval Sec. 6.3 3 documents example contd. Log frequency weigh(ng term SaS PaP A<er length normaliza(on WH term SaS PaP WH affection 3.06 2.76 2.30 affection 0.789 0.832 0.524 jealous 2.00 1.85 2.04 jealous 0.515 0.555 0.465 gossip 1.30 0 1.78 gossip 0.335 0 0.405 0 0 2.58 wuthering 0 0 0.588 wuthering cos(SaS,PaP) ≈ 0.789 × 0.832 + 0.515 × 0.555 + 0.335 × 0.0 + 0.0 × 0.0 ≈ 0.94 cos(SaS,WH) ≈ 0.79 cos(PaP,WH) ≈ 0.69 Why do we have cos(SaS,PaP) > cos(SAS,WH)? Introduc)on to Informa)on Retrieval Introduc*on to Informa(on Retrieval The Vector Space Model (VSM) Introduc)on to Informa)on Retrieval Introduc*on to Informa(on Retrieval Calcula*ng k- idf cosine scores in an IR system Introduc)on to Informa)on Retrieval S ec. 6.4 k- idf weigh*ng has many variants Columns headed ‘n’ are acronyms for w...
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