Coalitional Bayesian Autoencoders -- Towards explainable unsupervised deep learning
This work addresses explainability in unsupervised deep learning for sensor networks, but it is incremental as it builds on existing Bayesian Autoencoders.
The paper tackled the problem of misleading explanations in Bayesian Autoencoders due to high correlation among features, proposing a Coalitional BAE method that improved explanation quality in sensor network applications, as demonstrated on condition monitoring datasets.
This paper aims to improve the explainability of Autoencoder's (AE) predictions by proposing two explanation methods based on the mean and epistemic uncertainty of log-likelihood estimate, which naturally arise from the probabilistic formulation of the AE called Bayesian Autoencoders (BAE). To quantitatively evaluate the performance of explanation methods, we test them in sensor network applications, and propose three metrics based on covariate shift of sensors : (1) G-mean of Spearman drift coefficients, (2) G-mean of sensitivity-specificity of explanation ranking and (3) sensor explanation quality index (SEQI) which combines the two aforementioned metrics. Surprisingly, we find that explanations of BAE's predictions suffer from high correlation resulting in misleading explanations. To alleviate this, a "Coalitional BAE" is proposed, which is inspired by agent-based system theory. Our comprehensive experiments on publicly available condition monitoring datasets demonstrate the improved quality of explanations using the Coalitional BAE.