The defense will take place on wednesday 17th of september.

Title
Hardware Arithmetic Acceleration for Machine Learning and Scientic Computing.

Abstract
In a data-driven world, machine learning and scientific computing have become increasingly important, justifying dedicated hardware accelerators. This thesis explores the design and implementation of arithmetic units for such accelerators in Kalray’s Massively Parallel Processor Array.

Machine learning requires matrix multiplications that operate on very small number formats. In this context, this thesis studies the implementation of mixed-precision dot-product-and-add for various 8-bit and 16-bit formats (FP8, INT8, Posit8, FP16, BF16), using variants of a classic state-of-the-art technique, the long accumulator. It also introduces techniques to combine various input formats. Radically different methods are studied to scale to the larger range of 32-bit and 64-bit formats common in scientific computing.

This thesis also studies the evaluation of some elementary functions. An operator for exponential function (crucial for softmax computations) extends a state-of-the-art architecture to accept multiple input formats. The inverse square root function (used for layer normalisation) is accelerated by combining state-of-the-art techniques for range reduction, correctly rounded multipartite tables, and software iterative refinement techniques.

Date: 24/07/2025
Time: 10 am
Room: Amphitheatre Claude Chappe
Venue: Batiment Hedy Lamarr

Title
A study of energy consumption challenges in extended reality services over cellular networks

Abstract
Extended reality (XR) services are characterised by their heavy computational requirements throughout their life cycle. XR comprises multiple traffic modes consisting of 3D video and audio, haptics, sensor and pose information. Systems-related challenges relating to the creation, encoding, transmission, rendering and presentation of the application data from this class of services have increasingly become key areas of research inquiry from both a computational and energy viewpoint. Recently, new provisions have been made across different relevant standards to improve the capacity of these applications on mobile cellular networks. Our research investigates the energy-related challenges at both the RAN and UE levels.  We conduct our evaluations using system-level simulations (SLS) that adhere to the parameter specifications established by standardisation bodies.
We begin with a RAN-level energy reduction plus XR application enhancement strategy. With the cell switch off (CSO) technique proposed for BS deployment energy efficiency at low load, we evaluate the impact of an XR-capacity improvement criterion on the energy savings obtainable. Our analysis covers a European urban city using data from a European operator and system-level simulations according to the standard network operations.
In XR, UE energy-saving schemes are especially important since current delivery devices are still in early commercial development, making battery-saving techniques crucial. In this thesis, we use the Rel-18 improvements on the discontinuous reception (DRX) UE energy saving mechanism through state-of-the-art prediction algorithms to propose a traffic prediction-based non-integer DRX mechanism. We achieved significant energy savings without impeding the XR quality of service requirements.
Lastly, towards enhancing the capacity of XR on cellular networks in energy-saving mode, we propose a DRX plus QoE-aware scheduler (DQAS). Using SLS according to 3GPP specifications on XR QoE requirements, traffic model, and dense urban deployment scenarios, and following real traces from XR applications, we first evaluate a QoE-aware scheduler (QAS) for XR services. We introduced DRX awareness into QAS, jointly improving XR QoE and energy consumption. We analysed our results to identify the parameter window in which both metrics can be improved towards achieving the goal of XR capacity improvement on cellular networks.

Jury
– Riadh Dhaou, Professor des Universites (University of Toulouse), Rapporteur
– Thi-Mai-Trang Nguyen, Professeur des Universités (Sorbonne Paris Nord University), Rapporteure
– Nadjib Achir, Maître de Conférences HDR(Sorbonne Paris Nord University), Examinateur
– Herve Rivano, Professeur des Universités (INSA Lyon), Examinateur
– Razvan Stanica, Maître de Conférences HDR (INSA Lyon), Directeur de thèse

When
Monday 30 June at 10:00 am

Where
AE1 amphitheater, Gustave Ferrié building, 8 rue de la Physique, F-69621 Villeurbanne

https://insa-lyon-fr.zoom.us/j/95728542338

Title
Design of radio front-end architectures to meet low energy consumption or resource sharing objectives

Abstract
The contributions presented are structured around four main research areas :
i) the energy consumption of connected devices, with the proposal of asynchronous wake-up radio solutions;
ii) the harvesting of ambient electromagnetic energy;
iii) the design of UHF RFID tags that are robust to elongation or integrate sensing capabilities (humidity/temperature), and on the other hand, studies on the tag-to-tag communication concept;
iv) the reduction of the dynamic range of input signals of analog-to-digital converters, as well as the joint implementation of spatial modulation and a full-duplex mode.
Depending on the addressed topic, the studies presented in this manuscript include theoretical, simulation, experimental, and real-world testing, with particular attention to the non-idealities of the radio front-end building
blocks and their impact on performance.
Based on the acquired expertise and the collaborations conducted at the national and international levels in various contexts, the final section identifies several new research directions that are being considered.

Jury
Prof. Daniela DRAGOMIRESCU INSA Toulouse ; reviewer
Prof. Ioannis KRIKIDIS Université de Chypre ; reviewer
Prof. Smail TEDJINI Université Grenoble-Alpes, Grenoble INP; reviewer
Prof. Yvan DUROC Université Claude Bernard Lyon 1 ; examiner
Prof. Bruno ALLARD INSA Lyon ; examiner
Prof. Guillaume VILLEMAUD INSA Lyon ; examiner

When
The defense will take place on june 6th at 9 AM.

Where
INSA Lyon Campus,  CITI Laboratory, Amphi Chappe,  Building Hedy Lamarr, 6 Avenue des Arts 69621 Villeurbanne, France

https://insa-lyon-fr.zoom.us/j/91634868780?pwd=i5znUHEaIiuahaoIkrkL0g5DU9fEaD.1

Title
MultiScale-HPC Hybrid Architectures: Developing Computing Continuum Towards Sustainable Advanced Computing.

Jury
Prof. Eddy CARON (UCBL, Lyon, France)
Prof. Ewa DEELMAN (USC, Los Angeles, United States of America)
Prof. Michaël KRAJECKI (URCA, Reims, France)
Prof. Genoveva VARGAS SOLAR (CNRS, Lyon, France)
Prof. Bernd MOHR (JSU, Jülich, Germany)
Prof. Frédéric DESPREZ (INRIA, Grenoble, France)
Prof. Frédéric LE MOUËL (INSA, Lyon, France)

The defense will take place on mai 19th at 5 PM.

Title
Space Networking: Models and Methods

Where
INSA Lyon Campus, Amphi Chappe