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Sannara EK

Mardi 26 Novembre 2024

Personalized Federated Learning for Sensor-based Human Activity Recognition in Pervasive Heterogeneous Environments

Abstract:
Recent advancements in sensor technology and mobile computing have significantly enhanced pervasive computing applications, integrating smart devices into our environments to offer diverse user-oriented services. These services are further augmented by Machine Learning (ML) models that are increasingly embedded within devices to leverage local computational power and data. However, adapting ML to a user-centric paradigm—prioritizing personalized and generalized local models while ensuring data privacy—presents challenges. Federated Learning (FL), a meta-learning client-server framework, provides a promising solution by avoiding the need to communicate user data. Conventionally, FL has been adopted as a server-centric approach, aiming to aggregate and optimize a single generalized model while leveraging local devices' computing abilities and data for training. However, addressing the demands of pervasive computing necessitates a shift toward a client-centric paradigm.
 
This thesis investigates the application and challenges of client-centric FL in the sensor-based domain of Human Activity Recognition (HAR), which involves predicting physical movements from mobile devices like smartphones and smartwatches. We explore the benefits and limitations of this approach by devising several new evaluations that highlight the detrimental effects of heterogeneity among client's devices. Additionally, we propose necessary contributions to mitigate these effects, aiming to enhance the overall performance and reliability of client-centric FL in HAR applications.

 

To address the heterogeneity limitation, we present a novel FL aggregation technique that dynamically adjusts the model's architecture to suit the unique traits of individual clients. We then adopt lightweight transformer-based HAR architectures that are robust to changing environments and user habits. Additionally, we develop a novel pre-training pipeline using several public datasets to reduce the data requirements for local fine-tuning. Afterwards, we explore three categories of self-supervised learning techniques to further enhance the robustness of client models by utilizing unlabeled data. Finally, we introduce an embedding-to-prototype matching mechanism via an optimal transport plan to regularize clients within the FL framework, enforcing weight similarity and promoting model consistency.
 

Date et lieu

Mardi 26 Novembre à 9:00
Auditorium de l'IMAG
et Zoom

Composition du jury

Philippe Lalanda
Professeur des Universités, Université Grenoble Alpes (Directeur de thèse)
François Portet
Professeur des Universités, Université Grenoble Alpes (Co-directeur de thèse)
Jiannong Cao
Full Professor, The Hong Kong Polytechnic University (Rapporteur)
Cecilia Mascolo
Full Professor, University of Cambridge (Rapporteure)
Giovanni Neglia
Directeur de Recherche, Centre Inria d'Université Côte d'Azur (Examinateur)
Keiichi Yasumoto
Full Professor, Nara Institute of Science and Technology (Examinateur)
Vania Marangozova
Professeure des Universités, Université Grenoble Alpes (Examinatrice)
Jean-Michel Tran
Directeur Technique I.A., Naval Group (Invité)

Publié le 28 novembre 2024

Mis à jour le 21 janvier 2025