Transforming Large-Size to Lightweight Deep Neural Networks for IoT Applications

Deep Neural Networks (DNNs) have gained unprecedented popularity due to their high-order performance and automated feature extraction capability. This has encouraged researchers to incorporate DNN in different Internet of Things (IoT) applications in recent years. However, the colossal requirement of computation, energy, and storage of DNNs make their deployment prohibitive on resource-constrained IoT devices. Therefore, several compression techniques have been proposed in recent years to reduce the energy, storage, and computation requirements of the DNN. These techniques have utilized a different perspective for compressing a DNN with minimal accuracy compromise. This encourages us to comprehensively overview DNN compression techniques for the IoT. This article presents a comprehensive overview of existing literature on compressing the DNN that reduces energy consumption, storage, and computation requirements for IoT applications. We divide the existing approaches into five broad categories-network pruning, sparse representation, bits precision, knowledge distillation, and miscellaneous-based upon the mechanism incorporated for compressing the DNN. The article discusses the challenges associated with each category of DNN compression techniques and presents some prominent applications using IoT in conjunction with a compressed DNN. Finally, we provide a quick summary of existing work under each category with the future direction in DNN compression.