Neural Gaussian Copula for Variational Autoencoder

Prince Zizhuang Wang, William Yang Wang


Abstract
Variational language models seek to estimate the posterior of latent variables with an approximated variational posterior. The model often assumes the variational posterior to be factorized even when the true posterior is not. The learned variational posterior under this assumption does not capture the dependency relationships over latent variables. We argue that this would cause a typical training problem called posterior collapse observed in all other variational language models. We propose Gaussian Copula Variational Autoencoder (VAE) to avert this problem. Copula is widely used to model correlation and dependencies of high-dimensional random variables, and therefore it is helpful to maintain the dependency relationships that are lost in VAE. The empirical results show that by modeling the correlation of latent variables explicitly using a neural parametric copula, we can avert this training difficulty while getting competitive results among all other VAE approaches.
Anthology ID:
D19-1442
Volume:
Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP-IJCNLP)
Month:
November
Year:
2019
Address:
Hong Kong, China
Editors:
Kentaro Inui, Jing Jiang, Vincent Ng, Xiaojun Wan
Venues:
EMNLP | IJCNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
4333–4343
Language:
URL:
https://aclanthology.org/D19-1442
DOI:
10.18653/v1/D19-1442
Bibkey:
Cite (ACL):
Prince Zizhuang Wang and William Yang Wang. 2019. Neural Gaussian Copula for Variational Autoencoder. In Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP-IJCNLP), pages 4333–4343, Hong Kong, China. Association for Computational Linguistics.
Cite (Informal):
Neural Gaussian Copula for Variational Autoencoder (Wang & Wang, EMNLP-IJCNLP 2019)
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PDF:
https://aclanthology.org/D19-1442.pdf