MEDLINE is a very large database of abstracts of research papers in medical domain, maintained by the National Library of Medicine. Documents in MEDLINE are supplied with manually assigned keywords from a controlled vocabulary called MeSH terms, classified for each document into major MeSH terms describing the main topics of the document and minor MeSH terms giving more details on the document's topic. To search MEDLINE, we apply a query expansion strategy through automatic relevance feedback, with the following modification: we assign greater weights to the MeSH terms, with different modulation of the major and minor MeSH terms' weights. With this, we obtain 16% of improvement of the retrieval quality over the best known system.
Kwangcheol Shin, Sang-Yong Han, Alexander F. Gelbu