提出新模型联合全局与上下文截断,提升无监督图异常检测精度。
GCTAM: Global and Contextual Truncated Affinity Combined Maximization Model For Unsupervised Graph Anomaly Detection
- 结合上下文与全局信息动态截断异常节点
- 在Amazon和YelpChi上比顶尖方法提升15%~20%
- 适用于大规模图数据,性能优于多数现有模型
真实世界的信息网络中常出现异常节点,如恶意用户、虚假评论等。最新方法采用截断亲和力最大化(TAM)机制,在无需标签的情况下实现优异检测效果:通过增强正常节点间亲和力、截断异常节点亲和力来识别异常。然而,现有TAM方法依赖固定阈值截断可疑节点,忽略节点特异性及高阶亲和关系,导致正常与异常节点均出现无效截断,限制检测效果。为此,本文提出一种融合上下文与全局亲和力的截断模型(GCTAM),核心思想是利用上下文截断降低异常节点亲和力,同时通过全局截断增强正常节点亲和力。大量实验证明,该方法在多个大规模真实数据集上表现优异;尤其在Amazon与YelpChi数据集上,相比现有最优方法提升15%~20%。值得注意的是,该方法在大规模数据集Amazin-all和YelpChi-all上仍保持领先,而多数已有模型无法完成此类任务。
原文摘要 · Abstract (English)
Anomalies often occur in real-world information networks/graphs, such as malevolent users, malicious comments, banned users, and fake news in social graphs. The latest graph anomaly detection methods use a novel mechanism called truncated affinity maximization (TAM) to detect anomaly nodes without using any label information and achieve impressive results. TAM maximizes the affinities among the normal nodes while truncating the affinities of the anomalous nodes to identify the anomalies. However, existing TAM-based methods truncate suspicious nodes according to a rigid threshold that ignores the specificity and high-order affinities of different nodes. This inevitably causes inefficient truncations from both normal and anomalous nodes, limiting the effectiveness of anomaly detection. To this end, this paper proposes a novel truncation model combining contextual and global affinity to truncate the anomalous nodes. The core idea of the work is to use contextual truncation to decrease the affinity of anomalous nodes, while global truncation increases the affinity of normal nodes. Extensive experiments on massive real-world datasets show that our method surpasses peer methods in most graph anomaly detection tasks. In highlights, compared with previous state-of-the-art methods, the proposed method has +15\% $\sim$ +20\% improvements in two famous real-world datasets, Amazon and YelpChi. Notably, our method works well in large datasets, Amazin-all and YelpChi-all, and achieves the best results, while most previous models cannot complete the tasks.
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