Aizawa, A.: ¬An information-theoretic perspective of tf-idf measures (2003)
0.00
0.00447703 = product of:
0.03133921 = sum of:
0.03133921 = weight(_text_:based in 4155) [ClassicSimilarity], result of:
0.03133921 = score(doc=4155,freq=2.0), product of:
0.11767787 = queryWeight, product of:
3.0129938 = idf(docFreq=5906, maxDocs=44218)
0.03905679 = queryNorm
0.26631355 = fieldWeight in 4155, product of:
1.4142135 = tf(freq=2.0), with freq of:
2.0 = termFreq=2.0
3.0129938 = idf(docFreq=5906, maxDocs=44218)
0.0625 = fieldNorm(doc=4155)
0.14285715 = coord(1/7)
- Abstract
- This paper presents a mathematical definition of the "probability-weighted amount of information" (PWI), a measure of specificity of terms in documents that is based on an information-theoretic view of retrieval events. The proposed PWI is expressed as a product of the occurrence probabilities of terms and their amounts of information, and corresponds well with the conventional term frequency - inverse document frequency measures that are commonly used in today's information retrieval systems. The mathematical definition of the PWI is shown, together with some illustrative examples of the calculation.