Understanding the flow of information in Deep Neural Networks (DNNs) is a
challenging problem that has gain increasing attention over the last few years.
While several methods have been proposed to explain network predictions, there
have been only a few attempts to compare them from a theoretical perspective.
What is more, no exhaustive empirical comparison has been performed in the
past. In this work, we analyze four gradient-based attribution methods and
formally prove conditions of equivalence and approximation between them. By
reformulating two of these methods, we construct a unified framework which
enables a direct comparison, as well as an easier implementation. Finally, we
propose a novel evaluation metric, called Sensitivity-n and test the
gradient-based attribution methods alongside with a simple perturbation-based
attribution method on several datasets in the domains of image and text
classification, using various network architectures.

本研究旨在对四种基于梯度的属性方法进行分析，并在图像和文本分类领域的多个数据集上测试这些方法，提出了一种新的评估指标 Sensitivity-n，并在改进一些方法后建立了一个统一框架，使这些方法能够进行直接比较和更容易实现。