JHU Ad Hoc Experiments at CLEF 2008
For CLEF 2008 JHU conducted monolingual and bilingual experiments in the ad hoc TEL and Persian tasks. Additionally we performed several post hoc experiments using previous CLEF ad hoc tests sets in 13 languages.
In all three tasks we explored alternative methods of tokenizing documents including plain words, stemmed words, automatically induced segments, a single selected n-gram from each word, and all n-grams from words (i.e., traditional character n-grams). Character n-grams demonstrated consistent gains over ordinary words in each of these three diverse sets of experiments. Using mean average precision, relative gains of of 50-200% on the TEL task, 5% on the Persian task, and 18% averaged over 13 languages from past CLEF evaluations, were observed.
KeywordsAverage Precision Relevance Feedback Query Expansion Mean Average Precision Mean Average Precision Score
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- 1.Creutz, M., Lagus, K.: Unsupervised Morpheme Segmentation and Morphology Induction from Text Corpora Using Morfessor 1.0. Helsinki University of Technology Technical Report A81 (2005)Google Scholar
- 3.Mayfield, J., McNamee, P.: Single n-gram stemming. In: Proceedings of ACM SIGIR 2003, pp. 415–416 (2003)Google Scholar
- 5.McNamee, P., Mayfield, J.: Translating pieces of words. In: Proceedings of the 28th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, Salvador, Brazil, pp. 643–644 (2005)Google Scholar
- 6.McNamee, P., Nicholas, C., Mayfield, J.: Don’t Have a Stemmer?: Be Un+concern+ed. In: Proceedings of ACM SIGIR 2008, pp. 813–814 (2008)Google Scholar
- 7.Pirkola, A., Keskustalo, H., Leppänen, E., Känsälä, A., Järvelin, K.: Targeted s-gram matching: a novel n-gram matching technique for cross- and mono-lingual word form variants. Information Research 7(2) (2002)Google Scholar
- 8.Ponte, J.M., Croft, W.B.: A Language Modeling Approach to Information Retrieval. In: Proceedings of ACM SIGIR 1998, pp. 275–281 (1998)Google Scholar