论文标题
为多元时间序列生成稀疏的反事实解释
Generating Sparse Counterfactual Explanations For Multivariate Time Series
论文作者
论文摘要
由于神经网络在关键领域起着越来越重要的作用，因此解释网络预测已成为关键研究主题。反事实解释可以帮助理解为什么分类器模型决定特定类分配的原因，此外，必须如何修改各自的输入样本，以使类预测发生变化。以前的方法主要关注图像和表格数据。在这项工作中，我们提出了Sparce，这是一种生成对抗网络（GAN）体系结构，为多元时间序列生成稀疏的反事实解释。我们的方法提供了一个自定义的稀疏层，并根据相似性，稀疏性和轨迹平滑度将反事实损失函数正规化。我们评估了现实世界人类运动数据集的方法以及合成时间序列的可解释性基准。尽管我们比其他方法进行了明显的稀疏修改，但我们在所有指标上实现了可比或更好的性能。此外，我们证明我们的方法主要会修改显着的时间步骤和特征，从而使非偏好输入未经触及。
Since neural networks play an increasingly important role in critical sectors, explaining network predictions has become a key research topic. Counterfactual explanations can help to understand why classifier models decide for particular class assignments and, moreover, how the respective input samples would have to be modified such that the class prediction changes. Previous approaches mainly focus on image and tabular data. In this work we propose SPARCE, a generative adversarial network (GAN) architecture that generates SPARse Counterfactual Explanations for multivariate time series. Our approach provides a custom sparsity layer and regularizes the counterfactual loss function in terms of similarity, sparsity, and smoothness of trajectories. We evaluate our approach on real-world human motion datasets as well as a synthetic time series interpretability benchmark. Although we make significantly sparser modifications than other approaches, we achieve comparable or better performance on all metrics. Moreover, we demonstrate that our approach predominantly modifies salient time steps and features, leaving non-salient inputs untouched.
