Research Article

Study of Query Expansion Techniques and Their Application in the Biomedical Information Retrieval

Table 6

MAP values for the TF-IDF BM25, Raw TF, and formulas.

CombinationsParameters
Raw TF
1.20.7510001.30.61.21.20.71.2

Porter stemmer-NLM stopwords0.1861 0.18680.18610.14220.1749
Porter stemmer-SMART stopwords0.1866 0.18980.18780.14450.1742
Krovetz stemmer-NLM stopwords0.1821 0.18430.18270.14200.1736
Krovetz stemmer-SMART stopwords0.1828 0.18660.18390.14360.1731

The bold font refers to the best values for the parameters.