Unsupervised Discourse Constituency Parsing Using Viterbi EM (2020.tacl-1)

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Challenge: Existing studies on unsupervised discourse parsing have shown that it is expensive, time-consuming, and sometimes highly ambiguous.
Approach: They propose an unsupervised parsing algorithm using Viterbi EM with a margin-based criterion and initialization methods for Viterbia training of discourse constituents based on prior knowledge of text structures.
Outcome: The proposed method outperforms fully supervised parsers in terms of performance and learning of discourse constituents.

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