Now showing 1 - 2 of 2
  • Publication
    A Topic-Based Approach to Multiple Corpus Comparison
    (CEUR Workshop Proceedings, 2019-12-06) ; ;
    Corpus comparison techniques are often used to compare different types of online media, for example social media posts and news articles. Most corpus comparison algorithms operate at a word-level and results are shown as lists of individual discriminating words which makes identifying larger underlying differences between corpora challenging. Most corpus comparison techniques also work on pairs of corpora and do need easily extend to multiple corpora. To counter these issues, we introduce Multi-corpus Topic-based Corpus Comparison (MTCC) a corpus comparison approach that works at a topic level and that can compare multiple corpora at once. Experiments on multiple real-world datasets are carried demonstrate the effectiveness of MTCC and compare the usefulness of different statistical discrimination metrics - the χ2 and Jensen-Shannon Divergence metrics are shown to work well. Finally we demonstrate the usefulness of reporting corpus comparison results via topics rather than individual words. Overall we show that the topic-level MTCC approach can capture the difference between multiple corpora, and show the results in a more meaningful and interpretable way than approaches that operate at a word-level.
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  • Publication
    Diverging Divergences: Examining Variants of Jensen Shannon Divergence for Corpus Comparison Tasks
    Jensen-Shannon divergence (JSD) is a distribution similarity measurement widely used in natural language processing. In corpus comparison tasks, where keywords are extracted to reveal the divergence between different corpora (for example, social media posts from proponents of different views on a political issue), two variants of JSD have emerged in the literature. One of these uses a weighting based on the relative sizes of the corpora being compared. In this paper we argue that this weighting is unnecessary and, in fact, can lead to misleading results. We recommend that this weighted version is not used. We base this recommendation on an analysis of the JSD variants and experiments showing how they impact corpus comparison results as the relative sizes of the corpora being compared change.
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