A Pre-training Strategy for Recommendation.

The side information of items has been shown to be effective in building the recommendation systems. Various methods have been developed to exploit the item side information for learning users' preferences on items. Differing from previous work, this paper focuses on developing an unsupervised pre-training strategy, which can exploit the items' multimodality side information (e.g., text and images) to learn the item representations that may benefit downstream applications, such as personalized item recommendation and click-through ratio prediction. Firstly, we employ a multimodal graph to describe the relationships between items and their multimodal feature information. Then, we propose a novel graph neural network, named Multimodal Graph-BERT (MG-BERT), to learn the item representations based on the item multimodal graph. Specifically, MG-BERT is trained by solving the following two graph reconstruction problems, i.e., graph structure reconstruction and masked node feature reconstruction. Experimental results on real datasets demonstrate that the proposed MG-BERT can effectively exploit the multimodality information of items to help downstream applications.