A Text-based Deep Reinforcement Learning Framework Using Self-supervised Graph Representation for Interactive Recommendation

Due to its nature of learning from dynamic interactions and planning for long-run performance, Reinforcement Learning (RL) has attracted much attention in Interactive Recommender Systems (IRSs). However, most of the existing RL-based IRSs usually face large discrete action space problem, which severely limits their efficiency. Moreover, data sparsity is another problem that most IRSs are confronted with. The utilization of recommendation-related textual knowledge can tackle this problem to some extent, but existing RL-based recommendation methods either neglect to combine textual information or are not suitable for incorporating it. To address these two problems, in this article, we propose a T ext-based deep R einforcement learning framework using self-supervised G raph representation for I nteractive R ecommendation (TRGIR). Specifically, we leverage textual information to map items and users into a same feature space by a self-supervised embedding method based on the graph convolutional network, which greatly alleviates data sparsity problem. Moreover, we design an effective method to construct an action candidate set, which reduces the scale of the action space directly. Two types of representative reinforcement learning algorithms have been applied to implement TRGIR. Since the action space of IRS is discrete, it is natural to implement TRGIR with Deep Q-learning Network (DQN). In the TRGIR implementation with Deep Deterministic Policy Gradient (DDPG), denoted as TRGIR-DDPG, we design a policy vector, which can represent user’s preferences, to generate discrete actions from the candidate set. Through extensive experiments on three public datasets, we demonstrate that TRGIR-DDPG achieves state-of-the-art performance over several baselines in a time-efficient manner.