arXiv:2605.30166cs.SIcs.LG2026-05

用可变曲率图模型识别社交机器人,更准且抗干扰。

SAHG: Sector-Anisotropic Hyperbolic Graph Model for Social Bot Detection

论文配图:SAHG: Sector-Anisotropic Hyperbolic Graph Model for Social Bot Detection
图 1 · 摘自论文原文
  • 设计方向敏感的双通道超曲几何模型,自适应调整结构分辨率。
  • 在三个数据集上准确率与F1均领先,尤其在对抗性攻击下更稳定。
  • 适合反作弊、安全检测等需精准识别异常账号的场景。

大模型驱动的社交机器人能生成流畅拟人文本,使仅依赖内容的检测方法失效。但协同攻击仍留下关系模式——互动行为、相似性、共享邻域、社区位置和协同活动,这些是图方法可利用的证据。现有图检测方法面临两大挑战:一是欧氏图神经网络扭曲具有层级与无标度特性的社交图;虽超曲几何缓解了体积增长失配问题,但固定曲率模型对不同密度与分离需求的方向仍使用统一分辨率。二是关系证据不可靠:高级机器人会伪造异质连接,导致邻域聚合混合真假信号,稀释账户级证据。本文提出SAHG(Sector-Anisotropic Hyperbolic Graph),学习方向依赖的曲率场γ(u),实现结构方向上的自适应几何分辨率,并通过扇区原型将角度集中与对齐转化为分类器可读特征。为防止污染聚合淹没账户级证据,SAHG将账户特征与图邻域表示分别编码于两个独立的SAH通道,仅在分类器阶段融合。在Fox8-23、BotSim-24和MGTAB三个数据集上的实验表明,SAHG在所有基准上均取得最高准确率与F1值,显著优于基于特征、图、大模型及各向同性超曲基线。消融与几何分析验证了各向异性几何与双通道设计的有效性。

原文摘要 · Abstract (English)

LLM-driven social bots can generate fluent, human-like text, reducing the discriminative advantage of content-based detection alone. However, coordinated campaigns still leave relational patterns -- interactions, behavioral similarity, shared neighborhoods, community positions, and coordinated activity -- that graph-based methods can exploit. Existing graph detectors face two challenges when exploiting such evidence. First, Euclidean GNNs distort hierarchical and scale-free social graphs; while hyperbolic geometry addresses this volume-growth mismatch, fixed-curvature models still assign uniform geometric resolution to structural directions with different densities and separation needs. Second, relational evidence is not always reliable: sophisticated bots forge heterophilic connections with genuine users, causing neighborhood aggregation to mix bot and human signals and dilute account-level evidence. We propose SAHG (Sector-Anisotropic Hyperbolic Graph), addressing both challenges. SAHG learns a direction-dependent curvature field $γ(u)$ that adapts geometric resolution across structural directions, and uses sector prototypes to convert angular concentration and alignment into classifier-readable features. To prevent contaminated aggregation from overwhelming account-level evidence, SAHG encodes per-account features and graph-neighborhood representations in two independent SAH channels, fusing them only at the classifier. Experiments on Fox8-23, BotSim-24, and MGTAB show that SAHG achieves the highest accuracy and F1 on all three benchmarks, outperforming feature-based, graph-based, LLM-based, and isotropic hyperbolic baselines. Ablation and geometric analyses confirm the effectiveness of the anisotropic geometry and dual-channel design.

社交机器人图神经网络超曲几何反作弊

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