Expansion av sökfrågor med Svenskt OrdNät som termkälla

The purpose of this Masters thesis is to examine the performance of queries that are expanded by synonyms and hyponyms from Svenskt OrdNät, the Swedish version of the Princeton WordNet. Four different types of queries were constructed: a baseline query S1, the baseline query expanded with synonyms S2, the baseline query expanded with hyponyms S3 and finally the baseline query expanded with the synonyms and hyponyms used in S2 and S3. The terms for expansion were picked by hand. The queries were executed in the Query Performance Analyser QPA, a tool used in IR education and in experimental IR research for analysing and comparing the performance of individual queries. 20 topics from the test collection GP_HDINF were chosen for the experiment. The four query types were analyzed with regard to precision and recall. The experimental results suggest that expansion with synonyms is the most effective of the four query types, since this query type performs the highest average recall, with only a slight decline in precision. However, there is no great difference in performance between the different query types. Uppsatsnivå: D