Pruning Broad Learning System based on Adaptive Feature Evolution

Yuchen Liu, Kaixiang Yang, Zhiwen Yu, Zhulin Liu, Yifan Shi, C. L. Philip Chen

Abstract: The newly proposed Broad Learning System (BLS) offers an alternative way to deep learning which saves a time-consuming training process and powerful computing resources. However, the randomly generated feature nodes and lots of enhancement nodes in BLS may reduce the performance of the final classifier. Aiming at the problems in randomly generated feature nodes which suffer from unpredictability and need guidance, this paper proposes an adaptive feature nodes evolutionary algorithm (AFNE) to extract better features; While broad learning neural network often requires a large number of enhancement nodes parameters to ensure its performance, which easily leads to the redundancy or dependency between features, as well as the performance degradation of the final model. Therefore, this article also proposes a new criterion based on node sensitivity to prune the network enhancement layer nodes to remove redundant nodes, reduce the network scale, and increase the generalization ability. The proposed algorithm ADP-BLS can improve the accuracy and generalization performance of the final classifier through the evolution of feature nodes and the pruning of enhancement nodes. Extensive comparative experiments on real world data sets verify the effectiveness of the proposed ADP-BLS. At the same time, when verifying the module validity of the innovative algorithms added in this article, experiments also show that the AFNE and pruning method integrated into BLS can improve the model to a certain extent.