Title
Sequential Recommendation via Stochastic Self-Attention
Abstract
ABSTRACT Sequential recommendation models the dynamics of a user’s previous behaviors in order to forecast the next item, and has drawn a lot of attention. Transformer-based approaches, which embed items as vectors and use dot-product self-attention to measure the relationship between items, demonstrate superior capabilities among existing sequential methods. However, users’ real-world sequential behaviors are uncertain rather than deterministic, posing a significant challenge to present techniques. We further suggest that dot-product-based approaches cannot fully capture collaborative transitivity, which can be derived in item-item transitions inside sequences and is beneficial for cold start items. We further argue that BPR loss has no constraint on positive and sampled negative items, which misleads the optimization. We propose a novel STOchastic Self-Attention (STOSA) to overcome these issues. STOSA, in particular, embeds each item as a stochastic Gaussian distribution, the covariance of which encodes the uncertainty. We devise a novel Wasserstein Self-Attention module to characterize item-item position-wise relationships in sequences, which effectively incorporates uncertainty into model training. Wasserstein attentions also enlighten the collaborative transitivity learning as it satisfies triangle inequality. Moreover, we introduce a novel regularization term to the ranking loss, which assures the dissimilarity between positive and the negative items. Extensive experiments on five real-world benchmark datasets demonstrate the superiority of the proposed model over state-of-the-art baselines, especially on cold start items. The code is available in https://github.com/zfan20/STOSA.
Year
DOI
Venue
2022
10.1145/3485447.3512077
International World Wide Web Conference
Keywords
DocType
Citations 
Sequential Recommendation, Transformer, Self-Attention, Uncertainty
Conference
0
PageRank 
References 
Authors
0.34
24
8
Name
Order
Citations
PageRank
Ziwei Fan1113.87
Zhiwei Liu2192.68
Yu Wang310.70
Alice Wang400.34
Nazari Zahra551.43
Lei Zheng61659.28
Hao Peng716727.72
Philip S. Yu8306703474.16