Long- and Short- Term Sequential Recommendation with Temporal Interval

Abstract

Sequential recommendation aims to learn the changes of users' interests according to their historical behaviors and predict the most likely next item. Since user's historical behavior are sequential actions, user's interest in different time periods has different emphases. For predicting a user's next item, not only the recent behavior is important, but also long-term preference with all historical behaviors could not be ignored. Recently, self-attention based user preference modeling has drawn much attention for its advantages of fewer parameters and parallelism. However, most of the existing self-attention based model do not make a good distinction between the long-term and short-term preferences of users. Based on the observations, we design a sequential recommendation model based on a combination of long-term and short-term preference. On the one hand, considering the changes of users' interests in different periods, we divide the sequence of users' behaviors into different temporal windows. Then, we use GRU to capture users' interests in different temporal window. On the other hand, to better combine the global and local information of user's, we adopt a locally constrained multi-head attention mechanism based on Transformer encoder. On three real-world public datasets, we finally validate the efficacy of our method.