OSR: Toward Developing Efficient Federated Learning-based Human Activity Recognition using Optimal Server Representations

Federated Learning (FL) is a privacy-preserving algorithm that enables multiple clients to collaboratively train a global model without sharing their local data. This learning algorithm is particularly valuable in privacy-sensitive applications such as Human Activity Recognition (HAR), where users are reluctant to share their personal data. However, a conventional FL system suffers from data heterogeneity and communication overhead. To address these issues, we propose an efficient FL algorithm for image-based HAR using optimal server representations (OSR). OSR efficiently selects a representative set of privacy-preserved images for transmission to the server and improves the global model quality by training on privacy-preserved data. Our comprehensive experiments carried out on three public datasets, namely Stanford40, PPMI, and VOC2012, demonstrate the superiority of OSR in terms of performance and bandwidth usage compared to state-of-the-art approaches.