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arXiv 2407.03475cs.LG

JEPA如何避免噪声特征:深度线性自蒸馏网络的隐式偏置

How JEPA Avoids Noisy Features: The Implicit Bias of Deep Linear Self Distillation Networks

Apple(苹果公司)

Etai Littwin, Omid Saremi, Madhu Advani, Vimal Thilak, Preetum Nakkiran, Chen Huang, Joshua Susskind

AI总结:

本文通过分析深度线性模型的训练动力学,揭示了JEPA相比MAE更倾向于学习高影响力特征(高回归系数特征)的隐式偏置机制,从而解释了其为何能避免噪声特征并在实践中取得成功。

摘要:

数据表示的自监督学习存在两种相互竞争的范式。联合嵌入预测架构(JEPA)是一类架构,其中语义相似的输入被编码为彼此可预测的表示。JEPA框架下近期一种成功的方法是自蒸馏,即训练一个在线编码器来预测目标编码器的输出,有时会使用一个轻量级预测器网络。与之相对的是掩码自编码器(MAE)范式,在该范式中,编码器和解码器被训练为在数据空间而非潜在表示中重建输入的缺失部分。使用JEPA方法而非MAE的一个常见动机是,JEPA目标优先考虑抽象特征,而非细粒度的像素信息(后者可能不可预测且缺乏信息量)。在这项工作中,我们试图通过分析深度线性模型的训练动力学来理解这一经验观察背后的机制。我们发现了一个令人惊讶的机制:在一个简化的线性设置中,两种方法学习到相似的表示,JEPA偏置倾向于学习高影响力特征,即具有高回归系数的特征。我们的结果指出了在潜在空间中进行预测所具有的一种独特的隐式偏置,这可能有助于阐明其在实践中取得成功的原因。

英文摘要:

Two competing paradigms exist for self-supervised learning of data representations. Joint Embedding Predictive Architecture (JEPA) is a class of architectures in which semantically similar inputs are encoded into representations that are predictive of each other. A recent successful approach that falls under the JEPA framework is self-distillation, where an online encoder is trained to predict the output of the target encoder, sometimes using a lightweight predictor network. This is contrasted with the Masked AutoEncoder (MAE) paradigm, where an encoder and decoder are trained to reconstruct missing parts of the input in the data space rather, than its latent representation. A common motivation for using the JEPA approach over MAE is that the JEPA objective prioritizes abstract features over fine-grained pixel information (which can be unpredictable and uninformative). In this work, we seek to understand the mechanism behind this empirical observation by analyzing the training dynamics of deep linear models. We uncover a surprising mechanism: in a simplified linear setting where both approaches learn similar representations, JEPAs are biased to learn high-influence features, i.e., features characterized by having high regression coefficients. Our results point to a distinct implicit bias of predicting in latent space that may shed light on its success in practice.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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