On-Device Partial Learning Technique of Convolutional Neural Network for New Classes

Abstract

In general, Convolutional Neural Networks (CNNs) have a complex network structure consisted of heavy layers with huge number of parameters such as the convolutional, pooling, relu-activation, and fully-connected layers. Due to the complexity and computation load, CNNs are trained on a cloud environment. There are a couple of drawbacks on learning and performing on the cloud such as security problem of personal information and dependency of communication state. Recently, CNNs are directly trained at the mobile devices in order to alleviate those two drawbacks. Due to the resource limitation of the mobile devices, the structure of CNNs needs to be compressed or to reduce training overhead. In this paper, we propose an on-device partial learning technique with the following benefits: (1) does not require additional neural network structures, and (2) reduces unnecessary computation overhead. We select a subset of influential weights from a trained network to accommodate the new classification class. The selection is made based on the information of the contribution of each weight to output, which is measured using the entropy concept. In the experimental section, we demonstrate and analyze our method with a CNN image classifier using two datasets such as Mixed National Institute of Standards and Technology image data and Microsoft Common Objection in Context data. As a result, the computational resources at LeNet-5 and AlexNet showed performance improvements of 1.7× and 2.3×, respectively, and memory resources demonstrated performance improvements of 1.4× and 1.6×, respectively.