Unsupervised Abstractive Opinion Summarization by Generating Sentences with Tree-Structured Topic Guidance

Masaru Isonuma, Junichiro Mori, Danushka Bollegala, Ichiro Sakata


Abstract
Abstract This paper presents a novel unsupervised abstractive summarization method for opinionated texts. While the basic variational autoencoder-based models assume a unimodal Gaussian prior for the latent code of sentences, we alternate it with a recursive Gaussian mixture, where each mixture component corresponds to the latent code of a topic sentence and is mixed by a tree-structured topic distribution. By decoding each Gaussian component, we generate sentences with tree-structured topic guidance, where the root sentence conveys generic content, and the leaf sentences describe specific topics. Experimental results demonstrate that the generated topic sentences are appropriate as a summary of opinionated texts, which are more informative and cover more input contents than those generated by the recent unsupervised summarization model (Bražinskas et al., 2020). Furthermore, we demonstrate that the variance of latent Gaussians represents the granularity of sentences, analogous to Gaussian word embedding (Vilnis and McCallum, 2015).
Anthology ID:
2021.tacl-1.56
Volume:
Transactions of the Association for Computational Linguistics, Volume 9
Month:
Year:
2021
Address:
Cambridge, MA
Venue:
TACL
SIG:
Publisher:
MIT Press
Note:
Pages:
945–961
Language:
URL:
https://aclanthology.org/2021.tacl-1.56
DOI:
10.1162/tacl_a_00406
Bibkey:
Cite (ACL):
Masaru Isonuma, Junichiro Mori, Danushka Bollegala, and Ichiro Sakata. 2021. Unsupervised Abstractive Opinion Summarization by Generating Sentences with Tree-Structured Topic Guidance. Transactions of the Association for Computational Linguistics, 9:945–961.
Cite (Informal):
Unsupervised Abstractive Opinion Summarization by Generating Sentences with Tree-Structured Topic Guidance (Isonuma et al., TACL 2021)
Copy Citation:
PDF:
https://aclanthology.org/2021.tacl-1.56.pdf
Video:
 https://aclanthology.org/2021.tacl-1.56.mp4