Cold-start item recommendation for representation learning based on heterogeneous information networks with fusion side information

In recommendation systems, the cold-start problem refers to the situation that users or items have too few interaction events with the system to be recommended, such as clicks or ratings. The cold-start problem leads to the loss of new users and difficulty in recommending new items and weakens the performance of recommendations. In this paper, we focus on alleviating the cold-start problem of items. Previous work has used the structure of item homogeneous graphs to establish connections between items and generate item embeddings. However, the homogeneous graph of a single node cannot fully explore the potential structural features between users and goods. Due to the flexibility of heterogeneous data, recommendation systems can also employ the Heterogeneous Graph Neural Network(HGNN) to characterize complex, heterogeneous data. In this paper, a novel Heterogeneous Graph Embedding Learning based Skip-Gram (HSG) model is proposed to mitigate the cold-start problem. First, we introduce three different types of subnetworks and combine them to construct heterogeneous graphs. Then meaningful sequences of nodes are generated via meta-path-based random walk for network embedding. Finally, a Skip-Gram model incorporating side information is used to learn item representations. The learned node embeddings are used as pre-training for the Matrix Factorization (MF) model. The HSG model is proven to be effective by extensive experiments on four publicly available datasets.