arXiv:2507.14706cs.LGcs.AI2025-07被引 2

用因果原型注意力提升伪造交易检测,让生成数据更真实有效。

Fraud is Not Just Rarity: A Causal Prototype Attention Approach to Realistic Synthetic Oversampling

  • 通过原型注意力机制引导生成过程,增强类别区分能力。
  • 实现93.74%的F1分数和92.85%召回率,优于传统方法。
  • 适合关注可解释性与真实合成样本的反欺诈研究者。

由于真实世界数据中存在极端类别不平衡,且欺诈行为与正常交易间模式细微,信用卡欺诈检测仍具挑战。现有研究常采用GAN、VAE或混合生成模型对少数类生成合成样本,但仅针对少数类生成易导致分类器过度自信、潜在空间聚类分离差,影响实际检测性能。本文提出因果原型注意力分类器(CPAC),结合变分自编码器-生成对抗网络(VAE-GAN)编码器,通过原型注意力机制促进类别感知聚类与更优潜在空间结构,实现生成前的表征塑造。实验表明,使用CPAC的模型在未采用后处理采样增强的情况下,即达F1-score 93.74%与召回率92.85%,显著优于SMOTE及当前先进生成模型。消融研究与可视化进一步揭示了分类器驱动表示学习的优势与局限。代码已开源。

原文摘要 · Abstract (English)

Detecting fraudulent credit card transactions remains a significant challenge, due to the extreme class imbalance in real-world data and the often subtle patterns that separate fraud from legitimate activity. Existing research commonly attempts to address this by generating synthetic samples for the minority class using approaches such as GANs, VAEs (Variational Autoencoders), or hybrid generative models. However, these techniques, particularly when applied only to minority-class data, tend to result in overconfident classifiers and poor latent cluster separation, ultimately limiting real-world detection performance. In this study, we propose the Causal Prototype Attention Classifier (CPAC), an interpretable architecture that promotes class-aware clustering and improved latent space structure through prototype-based attention mechanisms and we couple it with the encoder of a Variational Autoencoder-Generative Adversarial Network (VAE-GAN) in order to achieve improved latent cluster separation moving beyond post-hoc sample augmentation. We compared CPAC-augmented models to traditional oversamplers, such as SMOTE, as well as to state-of-the-art generative models, both with and without CPAC-based latent classifiers. Our results show that classifier-guided latent shaping with CPAC delivers superior performance, achieving an F1-score of 93.74% and recall of 92.85%, along with improved latent cluster separation. Further ablation studies and visualizations provide deeper insight into the benefits and limitations of classifier-driven representation learning for fraud detection. The codebase for this work can be found at the following link: https://github.com/claudiunderthehood/VAEGAN-CPAC.git.

欺诈检测生成模型原型注意力可解释性

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