Inverse Classification for Comparison-based Interpretability in Machine Learning

In the context of post-hoc interpretability, this paper addresses the task of explaining the prediction of a classifier, considering the case where no information is available, neither on the classifier itself, nor on the processed data (neither the training nor the test data). It proposes an instance-based approach whose principle consists in determining the minimal changes needed to alter a prediction: given a data point whose classification must be explained, the proposed method consists in identifying a close neighbour classified differently, where the closeness definition integrates a sparsity constraint. This principle is implemented using observation generation in the Growing Spheres algorithm. Experimental results on two datasets illustrate the relevance of the proposed approach that can be used to gain knowledge about the classifier.Comment: preprin

Time Series Mining: Shapelet Discovery, Ensembling, and Applications

Time series is a prominent class of temporal data sequences that has the properties of being equally spaced in time, chronologically ordered, and highly dimensional. Time series classification is an important branch of time series mining. Existing time series classifiers operate either on row data in the time domain or into an alternate data space in the shapelets or frequency domains. Combining time series classifiers, is another powerful technique used to improve the classification accuracy. It was demonstrated that different classifiers can be expert in predicting different subset of classes over others. The challenge lies in learning the expertise of different base learners. In addition, the high dimensionality characteristic of time series data makes it difficult to visualize their distribution. In this thesis we developed a new time series ensembling methods in order to improve the predictive performance, investigated the interpretability of classifiers by leveraging the power of deep learning models and adjusting them to provide visual shapelets as a by-product of the classification task. Finally, we show application through problems of solar energetic particle events prediction