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arXiv 2104.06629cs.LGcs.AI
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保持互信息的反向传播:学习反演以获得可信归因

Mutual Information Preserving Back-propagation: Learn to Invert for Faithful Attribution

Sun Yat-Sen University(中山大学);Texas A&M University(德克萨斯A&M大学)

Huiqi Deng, Na Zou, Weifu Chen, Guocan Feng, Mengnan Du, Xia Hu

摘要:

已经提出了基于反向传播的可视化来解释深度神经网络(DNN),其中一些产生具有良好视觉质量的解释。然而,这些直观的可视化是否与网络决策有关存在疑问。最近的研究证实了这一怀疑,通过验证几乎所有这些修改后的反向传播可视化都不忠实于模型的决策过程。此外,这些可视化产生模糊的“相对重要性分数”,其中低值不能保证独立于最终的预测。因此,开发一种新的反向传播框架,保证理论的忠实性,并产生一个清晰的理解定量归因得分是非常必要的。为了实现这一目标,我们借助互信息理论来生成解释,研究每个输入神经元中编码了多少输出信息。基本思想是通过反向传播来学习源信号,使得输入和输出之间的互信息应当尽可能多地保留在输入和源信号之间的互信息中。此外,我们提出了一个互信息保持逆网络,称为MIP-IN,其中每一层的参数递归训练学习如何反转。在反演过程中,采用正向Relu运算,使一般解释适应特定输入。然后,我们经验性地证明,反相源信号满足完整性和极小性属性,这是一个忠实的解释至关重要。此外,实证研究验证了MIP-IN产生的解释的有效性。

英文摘要:

Back propagation based visualizations have been proposed to interpret deep neural networks (DNNs), some of which produce interpretations with good visual quality. However, there exist doubts about whether these intuitive visualizations are related to the network decisions. Recent studies have confirmed this suspicion by verifying that almost all these modified back-propagation visualizations are not faithful to the model's decision-making process. Besides, these visualizations produce vague "relative importance scores", among which low values can't guarantee to be independent of the final prediction. Hence, it's highly desirable to develop a novel back-propagation framework that guarantees theoretical faithfulness and produces a quantitative attribution score with a clear understanding. To achieve the goal, we resort to mutual information theory to generate the interpretations, studying how much information of output is encoded in each input neuron. The basic idea is to learn a source signal by back-propagation such that the mutual information between input and output should be as much as possible preserved in the mutual information between input and the source signal. In addition, we propose a Mutual Information Preserving Inverse Network, termed MIP-IN, in which the parameters of each layer are recursively trained to learn how to invert. During the inversion, forward Relu operation is adopted to adapt the general interpretations to the specific input. We then empirically demonstrate that the inverted source signal satisfies completeness and minimality property, which are crucial for a faithful interpretation. Furthermore, the empirical study validates the effectiveness of interpretations generated by MIP-IN.

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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