EAAI Journal 2026 Journal Article
BeLink: Behavior graph network for unsupervised user identity linkage
- Xingkong Ma
- Mengmeng Guo
- Houjie Qiu
- Yiqing Cai
With the development and rise of online social networks (OSNs), the user identity linkage (UIL) task has become a focal point in recent years, which aims to match accounts belonging to the same individual across different platforms. However, most efforts in UIL are based on labeled data or social graphs, which are frequently unavailable due to privacy or access constraints. Moreover, existing methods fail to address the need for fine-grained user behavior modeling for the UIL task. To address these challenges, we propose BeLink, an unsupervised UIL framework centered on a novel behavior graph construction mechanism. Our method is based on the insight of behavioral self-similarity that individuals often exhibit consistent behavior patterns across time and platforms. To capture behavioral consistency, we construct a user behavior graph for each pair of cross-platform users, where nodes represent short-term user activity segments, and edges encode their semantic correlations. To ensure an accurate representation of nodes, we first introduce a large language model (LLM) based textual apparent analysis that resolves cross-platform inconsistencies and unifies semantic content. Subsequently, we pretrain a behavior representation model on users’ self-behavior sequences to embed activities into a unified semantic space. To infer identity linkage, BeLink employs graph-based clustering and an entropy-weighted co-occurrence scoring mechanism. Experiments on real-world datasets demonstrate that BeLink effectively links user identities using only behavioral signals, achieving an average improvement of 11. 0% in hit rate at rank 1 (Hit@1) and 14. 7% in mean reciprocal rank (MRR), and consistently outperforms all baselines.