论文标题
转移的差异:量化表示形式之间的差异
Transferred Discrepancy: Quantifying the Difference Between Representations
论文作者
论文摘要
了解哪些信息神经网络捕获是深度学习的基本问题,并且研究不同的模型是否捕获相似的特征是实现此目标的第一步。先前的工作试图在特征矩阵上定义指标,以测量两个模型之间的差异。但是,不同的指标有时会导致矛盾的结论,并且尚无共识在哪些指标中适合在实践中使用。在这项工作中,我们提出了一个超越先前方法的新颖指标。回想一下,使用学习表示的最实际场景之一就是将它们应用于下游任务。我们认为我们应该基于类似的原则设计指标。为此,我们介绍了转移的差异(TD),这是一个新的指标,它根据其下游任务的性能定义了两个表示之间的差异。通过渐近分析,我们展示了TD与下游任务的相关性以及以这种任务依赖方式定义指标的必要性。特别是,我们还表明,在特定条件下,TD度量与以前的指标密切相关。我们的实验表明,TD可以为不同的下游任务提供细粒度的信息,对于从不同初始化训练的模型,在下游任务预测方面,学习的功能并不相同。我们发现TD也可以用于评估不同培训策略的有效性。例如,我们证明了经过适当的数据增强训练的模型可以改善概括,从而在TD方面捕获了更多相似的特征,而那些具有损害概括的数据增强的模型不会。这表明了一种培训策略,导致更强大的代表也可以训练可以更好地推广的模型。
Understanding what information neural networks capture is an essential problem in deep learning, and studying whether different models capture similar features is an initial step to achieve this goal. Previous works sought to define metrics over the feature matrices to measure the difference between two models. However, different metrics sometimes lead to contradictory conclusions, and there has been no consensus on which metric is suitable to use in practice. In this work, we propose a novel metric that goes beyond previous approaches. Recall that one of the most practical scenarios of using the learned representations is to apply them to downstream tasks. We argue that we should design the metric based on a similar principle. For that, we introduce the transferred discrepancy (TD), a new metric that defines the difference between two representations based on their downstream-task performance. Through an asymptotic analysis, we show how TD correlates with downstream tasks and the necessity to define metrics in such a task-dependent fashion. In particular, we also show that under specific conditions, the TD metric is closely related to previous metrics. Our experiments show that TD can provide fine-grained information for varied downstream tasks, and for the models trained from different initializations, the learned features are not the same in terms of downstream-task predictions. We find that TD may also be used to evaluate the effectiveness of different training strategies. For example, we demonstrate that the models trained with proper data augmentations that improve the generalization capture more similar features in terms of TD, while those with data augmentations that hurt the generalization will not. This suggests a training strategy that leads to more robust representation also trains models that generalize better.