Learning Category Distribution for Text Classification

Label smoothing has a wide range of applications in the machine learning field. Nonetheless, label smoothing only softens the targets by adding a uniform distribution into a one-hot vector, which cannot truthfully reflect the underlying relations among categories. However, learning category relations is of vital importance in many fields such as emotion taxonomy and open set recognition. In this work, we propose a method to obtain the label distribution for each category (category distribution) to reveal category relations. Furthermore, based on the learned category distribution, we calculate new soft targets to improve the performance of model classification. Compared with existing methods, our algorithm can improve neural network models without any side information or additional neural network module by considering category relations. Extensive experiments have been conducted on four original datasets and 10 constructed noisy datasets with three basic neural network models to validate our algorithm. The results demonstrate the effectiveness of our algorithm on the classification task. In addition, three experiments (arrangement, clustering, and similarity) are also conducted to validate the intrinsic quality of the learned category distribution. The results indicate that the learned category distribution can well express underlying relations among categories.