Madsen, Rasmus Elsborg1; Sigurdsson, Sigurdur1; Hansen, Lars Kai3; Larsen, Jan3
1 Department of Informatics and Mathematical Modeling, Technical University of Denmark2 Cognitive Systems, Department of Informatics and Mathematical Modeling, Technical University of Denmark3 Copenhagen Center for Health Technology, Center, Technical University of Denmark
Language independent 'bag-of-words' representations are surprisingly effective for text classification. The representation is high dimensional though, containing many inconsistent words for text categorization. These inconsistent words result in reduced generalization performance of subsequent classifiers, e.g., from ill-posed principal component transformations. In this communication our aim is to study the effect of reducing the least relevant words from the bag-of-words representation. We consider a new approach, using neural network based sensitivity maps and information gain for determination of term relevancy, when pruning the vocabularies. With reduced vocabularies, documents are classified using a latent semantic indexing representation and a probabilistic neural network classifier. Reducing the bag-of-words vocabularies with 90%-98%, we find consistent classification improvement using two mid size data-sets. We also study the applicability of information gain and sensitivity maps for automated keyword generation.
Proceedings of the 17th International Conference on Pattern Recognition, 2004. Icpr 2004, 2004
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17th International Conference on Pattern Recognition, 2004.