Evidential Conservative Q-Learning for Dynamic Recommendations

21 Sept 2023 (modified: 11 Feb 2024)Submitted to ICLR 2024EveryoneRevisionsBibTeX
Primary Area: reinforcement learning
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Keywords: dynamic recommendation, evidential uncertainty
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TL;DR: We develop an RL driven recommender system trained by a novel evidential conservative Q learning algorithm, which makes effective and conservative recommendations over time to capture user's long-term interest.
Abstract: Reinforcement learning (RL) has been leveraged in recommender systems (RS) to capture users' evolving preferences and continuously improve the quality of recommendations. In this paper, we propose a novel evidential conservative Q-learning framework (ECQL) that learns an effective and conservative recommendation policy by integrating evidence-based uncertainty and conservative learning. ECQL conducts evidence-aware explorations to discover items that locate beyond current observation but reflect users' long-term interests. Also, it provides an uncertainty-aware conservative view on policy evaluation to discourage deviating too much from users' current interests. Two central components of ECQL include a uniquely designed sequential state encoder and a novel conservative evidential-actor-critic (CEAC) module. The former generates the current state of the environment by aggregating historical information and a sliding window that contains the current user interactions as well as newly recommended items from RL exploration that may represent future interests. The latter performs an evidence-based rating prediction by maximizing the conservative evidential Q-value and leverages a ranking score to explore the item space for a more diverse and valuable recommendation. Experiments on multiple real-world dynamic datasets demonstrate the state-of-the-art performance of ECQL and its capability to capture users' long-term interests.
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Submission Number: 4158
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