HierCas: Hierarchical Temporal Graph Attention Networks for Popularity Prediction in Information Cascades

Information cascade popularity prediction is critical for many applications, including but not limited to identifying fake news and accurate recommendations. Traditional feature-based methods heavily rely on handcrafted features, which are domain-specific and lack generalizability to new domains. To address this problem, researchers have turned to neural network-based approaches. However, existing methods follow a sampling-based modeling approach, potentially losing continuous dynamic information and structural-temporal dependencies that emerge during the information diffusion process. In this paper, we propose a novel framework called Hierarchical Temporal Graph Attention Networks for cascade popularity prediction (HierCas). Unlike existing methods, HierCas operates on the entire cascade graph by a dynamic graph modeling approach, enabling it to capture the full range of continuous dynamic information and explicitly model the interplay between structural and temporal factors. By leveraging time-aware node embedding, graph attention mechanisms and hierarchical pooling structures, HierCas effectively captures the popularity trend implicit in the complex cascade. Extensive experiments conducted on two real-world datasets in different scenarios demonstrate that our HierCas significantly outperforms the state-of-the-art approaches.

Deep supervision with additional labels for retinal vessel segmentation task

Automatic analysis of retinal blood images is of vital importance in diagnosis tasks of retinopathy. Segmenting vessels accurately is a fundamental step in analysing retinal images. However, it is usually difficult due to various imaging conditions, low image contrast and the appearance of pathologies such as micro-aneurysms. In this paper, we propose a novel method with deep neural networks to solve this problem. We utilize U-net with residual connection to detect vessels. To achieve better accuracy, we introduce an edge-aware mechanism, in which we convert the original task into a multi-class task by adding additional labels on boundary areas. In this way, the network will pay more attention to the boundary areas of vessels and achieve a better performance, especially in tiny vessels detecting. Besides, side output layers are applied in order to give deep supervision and therefore help convergence. We train and evaluate our model on three databases: DRIVE, STARE, and CHASEDB1. Experimental results show that our method has a comparable performance with AUC of 97.99% on DRIVE and an efficient running time compared to the state-of-the-art methods.