Affiliations: Department of Electrical, Computer and Software Engineering, Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, Oshawa, ON, Canada
Correspondence:
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Corresponding author: Masoud Makrehchi, Department of Electrical, Computer and Software Engineering, Faculty of Engineering and Applied Science, University of Ontario Institute of Technology (UOIT), 2000 Simcoe Street North, Oshawa, Ontario L1H 7K4, Canada. E-mail:masoud.makrehchi@uoit.ca
Abstract: In this paper, an automatic generation of domain-specific stopwords
from a large labeled corpus is proposed. In the majority of text mining tasks, stopwords are removed according to a standard stopword list and/or using high and low document frequencies. In this paper,
a new approach for stopword extraction, based on the notion of
backward filter-level performance and data sparsity index, is
proposed. First, based on the proposed model to evaluate the
extracted stopwords, we examine high document frequency filtering
for stopword reduction. Secondly, a new algorithm for building
general and domain-specific stopword lists is proposed. For the
method, it is assumed that a set of candidate stopwords must have a
minimum information content and prediction capacity that is measured
by the performance of a classifier. We show that to avoid obtaining
the classifier performance, it can be estimated by the sparsity of the training dataset. Moreover, it is confirmed that even if a given term ranking measure can perform well for the feature
selection, the measure is not necessarily efficient for selecting
poor features (stopwords). According to the comparative study, the newly devised
approach offers more promising results that guarantee a minimum
information loss by filtering out most stopwords.
Keywords: Text classification, stopwords, stopword reduction, feature selection
