CSaRUS-CNN at AMIA-2017 Tasks 1, 2: Under sampled CNN for text classification

Most practical text classification tasks in natural language processing involve training sets where the number of training instances belonging to each of the classes are not equal. The performance of the classifier in such a case can be affected by the sampling strategies used in training. In this work, we describe a cost sensitive and random undersampling variants of convolutional neural networks (CNNs) for classifying texts in imbalanced datasets and analyze its results. The classifier proposed in this paper achieves a maximum F1-score of 0.414 placing 2nd on the ADR dataset and achieves a maximum F1-score of 0.652 placing 6th on the medication intake dataset.