论文标题
逃脱鞍点以有效地概括为治疗数据
Escaping Saddle Points for Effective Generalization on Class-Imbalanced Data
论文作者
论文摘要
现实世界数据集表现出不同类型和学位的不平衡。基于重新加权和损失保证金调整的几种技术通常用于增强神经网络的性能,尤其是在少数群体上。在这项工作中,我们通过检查经过重新加权和基于利润的技术训练的神经网络的损失格局来分析班级的学习问题。具体而言,我们检查了阶级损失的Hessian的光谱密度,通过该密度,我们观察到网络的权重融合到少数群体损失景观中的鞍点。在此观察之后,我们还发现,可以有效地使用旨在逃脱鞍点的优化方法来改善对少数类别的概括。我们从理论上和经验上进一步证明了敏锐感知的最小化(SAM)是一种近期鼓励融合扁平最小值的技术,可有效地用于逃避少数群体的鞍点。使用SAM导致少数类别的准确性比最新的矢量缩放损失提高了6.2 \%,导致不平衡数据集的总体平均增加4 \%。该代码可在以下网址提供:https://github.com/val-iisc/saddle-longtail。
Real-world datasets exhibit imbalances of varying types and degrees. Several techniques based on re-weighting and margin adjustment of loss are often used to enhance the performance of neural networks, particularly on minority classes. In this work, we analyze the class-imbalanced learning problem by examining the loss landscape of neural networks trained with re-weighting and margin-based techniques. Specifically, we examine the spectral density of Hessian of class-wise loss, through which we observe that the network weights converge to a saddle point in the loss landscapes of minority classes. Following this observation, we also find that optimization methods designed to escape from saddle points can be effectively used to improve generalization on minority classes. We further theoretically and empirically demonstrate that Sharpness-Aware Minimization (SAM), a recent technique that encourages convergence to a flat minima, can be effectively used to escape saddle points for minority classes. Using SAM results in a 6.2\% increase in accuracy on the minority classes over the state-of-the-art Vector Scaling Loss, leading to an overall average increase of 4\% across imbalanced datasets. The code is available at: https://github.com/val-iisc/Saddle-LongTail.