Split Learning for Distributed Collaborative Training of Deep Learning Models in Health Informatics

Deep learning continues to rapidly evolve and is now demonstrating remarkable potential for numerous medical prediction tasks. However, realizing deep learning models that generalize across healthcare organizations is challenging. This is due, in part, to the inherent siloed nature of these organizations and patient privacy requirements. To address this problem, we illustrate how split learning can enable collaborative training of deep learning models across disparate and privately maintained health datasets, while keeping the original records and model parameters private. We introduce a new privacy-preserving distributed learning framework that offers a higher level of privacy compared to conventional federated learning. We use several biomedical imaging and electronic health record (EHR) datasets to show that deep learning models trained via split learning can achieve highly similar performance to their centralized and federated counterparts while greatly improving computational efficiency and reducing privacy risks.

High speed free-space optical communication using standard fiber communication component without optical amplification

Free-space optical communication (FSO) can achieve fast, secure and license-free communication without need for physical cables, making it a cost-effective, energy-efficient and flexible solution when the fiber connection is absent. To establish FSO connection on-demand, it is essential to build portable FSO devices with compact structure and light weight. Here, we develop a miniaturized FSO system and realize 9.16 Gbps FSO between two nodes that is 1 km apart, using a commercial fiber-coupled optical transceiver module with no optical amplification. Basing on the home-made compact 90 mm-diameter acquisition, pointing and tracking (APT) system with four-stage close-loop feedback, the link tracking error is controlled at 3 {\mu}rad and results an average coupling loss of 13.7 dB. Such loss is within the tolerance of the commercial optical communication modules, and without the need of optical amplifiers, which contributes to the low system weight and power consumption. As a result, a single FSO device weighs only about 12 kg, making it compact and portable for potential application in high-speed wireless communication. Our FSO link has been tested up to 4 km, with link loss of 18 dB in the foggy weather in Nanjing, that shows longer distances can be covered with optical amplification.