arXiv:2412.15657cs.LG2024-12AAAI被引 19

通过引入重叠类,显著提升不平衡数据生成质量。

Synthetic Tabular Data Generation for Imbalanced Classification: The Surprising Effectiveness of an Overlap Class

  • 将二分类转为三分类,新增重叠区域类别以缓解生成偏差
  • 在多个真实数据集上,合成数据质量与分类准确率均明显提升
  • 适用于希望改善少数类生成效果的研究者和工程师

在构建表格数据分类器时处理类别分布不均衡问题长期受到关注。一种流行方法是通过合成数据扩充训练集。传统方法仅限于对少数类样本进行线性插值,而近期高容量深度生成模型展现出更大潜力。然而,训练深度生成模型时对类别不均衡的处理尚未得到充分研究。我们发现,当前最先进的生成模型产生的少数类样本质量远低于多数类样本。本文观察到:在类别不平衡的数据集上训练生成模型会导致少数类代表性不足。为此,我们提出一种新方法:将二元类别标签转换为三元标签,引入一个表示少数类与多数类分布重叠区域的新类别。仅通过这一预处理步骤,即可显著提升多种先进扩散模型与GAN模型生成数据的质量。在后续分类器训练中,移除重叠类别并解释其有效性。我们在四个真实数据集、五种分类器及五种生成模型上进行了广泛实验,结果表明该方法不仅提升了生成模型性能,也增强了分类器表现。

原文摘要 · Abstract (English)

Handling imbalance in class distribution when building a classifier over tabular data has been a problem of long-standing interest. One popular approach is augmenting the training dataset with synthetically generated data. While classical augmentation techniques were limited to linear interpolation of existing minority class examples, recently higher capacity deep generative models are providing greater promise. However, handling of imbalance in class distribution when building a deep generative model is also a challenging problem, that has not been studied as extensively as imbalanced classifier model training. We show that state-of-the-art deep generative models yield significantly lower-quality minority examples than majority examples. %In this paper, we start with the observation that imbalanced data training of generative models trained imbalanced dataset which under-represent the minority class. We propose a novel technique of converting the binary class labels to ternary class labels by introducing a class for the region where minority and majority distributions overlap. We show that just this pre-processing of the training set, significantly improves the quality of data generated spanning several state-of-the-art diffusion and GAN-based models. While training the classifier using synthetic data, we remove the overlap class from the training data and justify the reasons behind the enhanced accuracy. We perform extensive experiments on four real-life datasets, five different classifiers, and five generative models demonstrating that our method enhances not only the synthesizer performance of state-of-the-art models but also the classifier performance.

数据生成不平衡学习生成模型表格数据

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