Research Article
Study of Query Expansion Techniques and Their Application in the Biomedical Information Retrieval
Table 5
Testing values of the parameters for BM25. MAP is used as the evaluation measure.
(a) The best value obtained for the parameter |
| Combinations | Parameters | | | | | | | | | | | | | | | | | | | | | | 0 | 0.75 | 1.2 | 1 | 0.75 | 1.2 | 2 | 0.75 | 1.2 | 1.5 | 0.75 | 1.2 | 1.3 | 0.75 | 1.2 | 1.2 | 0.75 | 1.2 | 1.4 | 0.75 | 1.2 |
| Porter stemmer-NLM stopwords
| 0.1521 | 0.1803 | 0.1792 | 0.1792 | 0.1807 | 0.1798 | 0.1792 | Porter stemmer-SMART stopwords
| 0.1531 | 0.1820 | 0.1783 | 0.1788 | 0.1813 | 0.1815 | 0.1807 | Krovetz stemmer-NLM stopwords
| 0.1521 | 0.1797 | 0.1778 | 0.1802 | 0.1804 | 0.1806 | 0.1799 | Krovetz stemmer-SMART stopwords | 0.1557 | 0.1828 | 0.1793 | 0.1801 | 0.1824 | 0.1815 | 0.1819 |
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The bold font refers to the best values for the parameters.
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(b) The best value obtained for the parameter |
| Combinations | Parameters | | | | | | | | | | | | | | | | | | | | | | 1.3 | 0 | 1.2 | 1.3 | 1 | 1.2 | 1.3 | 0.75 | 1.2 | 1.3 | 0.65 | 1.2 | 1.3 | 0.6 | 1.2 | 1.3 | 0.55 | 1.2 | 1.3 | 0.70 | 1.2 |
| Porter stemmer-NLM stopwords
| 0.1652 | 0.1715 | 0.1807 | 0.1810 | 0.1824 | 0.1821 | 0.1799 | Porter stemmer-SMART stopwords
| 0.1669 | 0.1695 | 0.1813 | 0.1816 | 0.1814 | 0.1808 | 0.1817 | Krovetz stemmer-NLM stopwords
| 0.1667 | 0.1706 | 0.1804 | 0.1802 | 0.1819 | 0.1819 | 0.1795 | Krovetz stemmer-SMART stopwords | 0.1701 | 0.1707 | 0.1824 | 0.1823 | 0.1824 | 0.1821 | 0.1818 |
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The bold font refers to the best values for the parameters.
|
(c) The best value obtained for the parameter. |
| Combinations | Parameters | | | | | | | | | | | | | | | | | | | | | | 1.3 | 0.6 | 0 | 1.3 | 0.6 | 1 | 1.3 | 0.6 | 2 | 1.3 | 0.6 | 7 | 1.3 | 0.6 | 1.5 | 1.3 | 0.6 | 1.2 | 1.3 | 0.6 | 1.3 |
| Porter stemmer-NLM stopwords
| 0.1824 | 0.1825 | 0.1824 | 0.1817 | 0.1823 | 0.1824 | 0.1822 | Porter stemmer-SMART stopwords
| 0.1814 | 0.1813 | 0.1813 | 0.1810 | 0.1814 | 0.1814 | 0.1814 | Krovetz stemmer-NLM stopwords
| 0.1811 | 0.1819 | 0.1825 | 0.1815 | 0.1822 | 0.1819 | 0.1819 | Krovetz stemmer-SMART stopwords | 0.1817 | 0.1822 | 0.1820 | 0.1815 | 0.1824 | 0.1824 | 0.1824 |
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The bold font refers to the best values for the parameters.
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