Knowledge-Driven Graph Similarity for Text Classification

Automatic text classification using machine learning is significantly
affected by the text representation model. The structural information in text
is necessary for natural language understanding, which is usually ignored in
vector-based representations. In this paper, we present a graph kernel-based
text classification framework which utilises the structural information in text
effectively through the weighting and enrichment of a graph-based representation.
We introduce weighted co-occurrence graphs to represent text documents,
which weight the terms and their dependencies based on their relevance to text
classification. We propose a novel method to automatically enrich the weighted
graphs using semantic knowledge in the form of a word similarity matrix. The
similarity between enriched graphs, knowledge-driven graph similarity, is calculated using a graph kernel. The semantic knowledge in the enriched graphs
ensures that the graph kernel goes beyond exact matching of terms and patterns
to compute the semantic similarity of documents. In the experiments
on sentiment classification and topic classification tasks, our knowledge-driven
similarity measure significantly outperforms the baseline text similarity measures
on five benchmark text classification datasets.