Constrained Policy Optimization for Controlled Self-Learning in Conversational AI Systems

Mohammad Kachuee, Sungjin Lee


Abstract
Recently, self-learning methods based on user satisfaction metrics and contextual bandits have shown promising results to enable consistent improvements in conversational AI systems. However, directly targeting such metrics by off-policy bandit learning objectives often increases the risk of making abrupt policy changes that break the current user experience. In this study, we introduce a scalable framework for supporting fine-grained exploration targets for individual domains via user-defined constraints. For example, we may want to ensure fewer policy deviations in business-critical domains such as shopping, while allocating more exploration budget to domains such as music. We present a novel meta-gradient learning approach that is scalable and practical to address this problem. The proposed method adjusts constraint violation penalty terms adaptively through a meta objective that encourages balanced constraint satisfaction across domains. We conducted extensive experiments on a real-world conversational AI and using a set of realistic constraint benchmarks. The proposed approach has been deployed in production for a large-scale commercial assistant, enabling the best balance between the policy value and constraint satisfaction rate.
Anthology ID:
2023.acl-industry.5
Volume:
Proceedings of the 61st Annual Meeting of the Association for Computational Linguistics (Volume 5: Industry Track)
Month:
July
Year:
2023
Address:
Toronto, Canada
Editors:
Sunayana Sitaram, Beata Beigman Klebanov, Jason D Williams
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
43–52
Language:
URL:
https://aclanthology.org/2023.acl-industry.5
DOI:
10.18653/v1/2023.acl-industry.5
Bibkey:
Cite (ACL):
Mohammad Kachuee and Sungjin Lee. 2023. Constrained Policy Optimization for Controlled Self-Learning in Conversational AI Systems. In Proceedings of the 61st Annual Meeting of the Association for Computational Linguistics (Volume 5: Industry Track), pages 43–52, Toronto, Canada. Association for Computational Linguistics.
Cite (Informal):
Constrained Policy Optimization for Controlled Self-Learning in Conversational AI Systems (Kachuee & Lee, ACL 2023)
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PDF:
https://aclanthology.org/2023.acl-industry.5.pdf