Aizawa, A.: ¬An information-theoretic perspective of tf-idf measures (2003)
0.01
0.0059341122 = product of:
0.02967056 = sum of:
0.02967056 = weight(_text_:of in 4155) [ClassicSimilarity], result of:
0.02967056 = score(doc=4155,freq=22.0), product of:
0.06472395 = queryWeight, product of:
1.5637573 = idf(docFreq=25162, maxDocs=44218)
0.041390024 = queryNorm
0.458417 = fieldWeight in 4155, product of:
4.690416 = tf(freq=22.0), with freq of:
22.0 = termFreq=22.0
1.5637573 = idf(docFreq=25162, maxDocs=44218)
0.0625 = fieldNorm(doc=4155)
0.2 = coord(1/5)
- 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.