With the rising need of interpretable machine learning methods, there is a necessity for a rise in human effort to provide diverse explanations of the influencing factors of the model decisions. To improve the trust and transparency of AI-based systems, the EXplainable Artificial Intelligence (XAI) field has emerged. The XAI paradigm is bifurcated into two main categories: feature attribution and counterfactual explanation methods. While feature attribution methods are based on explaining the reason behind a model decision, counterfactual explanation methods discover the smallest input changes that will result in a different decision. In this paper, we aim at building trust and transparency in time series models by using motifs to generate counterfactual explanations. We propose Motif-Guided Counterfactual Explanation (MG-CF), a novel model that generates intuitive post-hoc counterfactual explanations that make full use of important motifs to provide interpretive information in decision-making processes. To the best of our knowledge, this is the first effort that leverages motifs to guide the counterfactual explanation generation. We validated our model using five real-world time-series datasets from the UCR repository. Our experimental results show the superiority of MG-CF in balancing all the desirable counterfactual explanations properties in comparison with other competing state-of-the-art baselines.

随着机器学习和深度学习模型在多种领域变得非常普遍，因此采用决策过程的主要保留是它们的黑盒本质。可解释的人工智能（XAI）范式由于其能够降低模型不透明度的能力而获得了很多动力。 XAI方法不仅增加了利益相关者对决策过程的信任，而且还帮助开发商确保了其公平性。最近的努力用于创建透明的模型和事后解释。但是，对于时间序列数据，开发了更少的方法，而在多元数据集方面甚至更少。在这项工作中，我们利用塑形组的固有解释性来开发模型不可知的多元时间序列（MTS）反事实解释算法。反事实可能会通过指示在输入上必须执行哪些更改以改变最终决定，从而对制作黑框模型产生巨大影响。我们在现实生活中的太阳耀斑预测数据集上测试了我们的方法，并证明我们的方法会产生高质量的反事实。此外，与唯一的MTS反事实生成算法的比较表明，除了视觉上可以解释外，我们的解释在接近性，稀疏性和合理性方面也很出色。