Session-based recommendation with an importance extraction module

Abstract

The goal of session-based recommendation is to make item predictions at the next timestamp based on the anonymous ongoing session. Previous work mainly models user’s preference by exploring the transition pattern between the interacted items in the session. However, they generally fail to pay enough attention to the item importance in terms of the relevance of the items to user’s main purpose. This paper proposes a Session-based Recommendation approach with an Importance Extraction Module, i.e., SR-IEM$_{{{\text{improved}}}}$, which can simultaneously consider user’s long-term interactions and recent behavior in current session. Specifically, we modify the self-attention mechanism to avoid introducing bias for estimating the importance of each item in the session. Then, the item importances are utilized to produce user’s long-term preference, and the sequential signals are incorporated in the long-term interest modeling. Next, the long-term preference and user’s current interest which is conveyed by the last interacted item in the session are combined to obtain user’s final preference representation. Finally, item predictions are generated using the user preference, where a normalization layer is adopted to solve the long-tail problem. Extensive experiments are conducted on three public benchmark datasets, i.e., Yoochoose 1/64, Yoochoose 1/4 and Diginetica. The experimental results show that SR-IEM$_{{{\text{improved}}}}$ can outperform the start-of-the-art baselines in terms of Recall and MRR for session-based recommendation. In addition, compared to the state-of-the-art neural methods, SR-IEM$_{{{\text{improved}}}}$ can obviously reduce the computational complexity.