« Compilation of Real-Time Audio DSP on FPGA »

Doctorant : Maxime POPOFF

Laboratoire INSA : CITI
École doctorale : ED512 : Infomaths

La mise en œuvre du traitement du signal numérique (DSP) audio en temps réel sur FPGA a été largement étudiée dans le passé. Jusqu’à présent, les designs hardwares audio étaient conçues soit "à la main" en VHDL, soit en assemblant des IPs prédéfinies dans des environnements dédiés. L’avènement de la synthèse de haut niveau (HLS) permet un véritable flux de compilation depuis les spécifications DSP audio de haut niveau jusqu’aux flux binaires FPGA. Cette thèse présente les principes et l’implémentation du premier “compilateur DSP audio” ciblant les FPGA.
Notre système compile les programmes DSP audio exprimés dans le langage Faust ou C++ jusqu’au matériel FPGA et jusqu’à la production sonore réelle. De nombreux paramètres tels que le nombre de canaux de sortie, le taux d’échantillonnage, etc. sont ajustés automatiquement par le compilateur. Des interfaces logicielles peuvent être générées pour contrôler le système en temps réel. Ce flot de compilation présente deux avancées technologiques importantes pour les programmeurs audio : l’implémentation de programmes DSP audio en temps réel à très faible latence (quelques microsecondes) et la possibilité de déployer facilement des systèmes avec un grand nombre de canaux audio.

 

Privacy issues in AI and geolocation : from data protection to user awareness

Maître de Conférences : Antoine Boutet

Laboratoire INSA :  CITI

Rapporteurs : Catuscia Palamidessi, Aurélien Bellet et Romain Rouvoy

Jury :

Civilité	Nom et Prénom	Grade/Qualité	Etablissement
M.	Taiani François	Professeur des Universités	Université de Rennes 1
Mme	Palamidessi Catuscia	Directrice de Recherche	Inria
M.	Rouvoy Romain	Professeur des Universités	Université de Lille
M.	Bellet Aurélien	Directeur de Recherche	Inria
Mme	Ben Mokhtar Sonia	Directrice de Recherche	CNRS, Insa-Lyon
Mme	Kermarrec Anne-Marie	Professeure des Universités	EPFL
M.	Monnet Sébastien	Professeur des Universités	Université Savoie Mont-Blanc
M.	Caron Eddy	Professeur des Universités	Université Lyon 1

Supporting meaningful and adapted experience to foster motivation and sustained engagement.

Maître de conférences : Audrey SERNA

Laboratoire INSA : LIRIS

Rapporteurs : Wendy Mackay, Jean-Claude Martin, Vero Vanden Abeele
Jury : 

Civilité	Nom et Prénom	Grade/Qualité	Etablissement
Mme	Dupuy Chessa Sophie	Professeur des Universités	Université Grenoble Alpes
M	Garcia Christophe	Professeur des Universités	INSA Lyon
M	Hacid Mohand-Saïd	Professeur des Universités	Université Claude Bernard Lyon 1
Mme	Lavoué Elise	Professeur des Universités	Université Jean Moulin Lyon 3
Mme	Mackay Wendy	Directrice de Recherche	INRIA Saclay
M	Martin Jean-Claude	Professeur des Universités	Université Paris Saclay
Mme	Vanden Abeele Vero	Associate Professor	KU Leuven

« Systèmes de Jumeau Numérique pour les systèmes de production : application sur le manufacturing lab »

Doctorante : Xeniya PYSTINA 

Laboratoire INSA : DISP

École doctorale : ED512 : InfoMaths (Informatique et Mathématiques de Lyon)

Traditional production systems face major challenges in transitioning to Industry 4.0 (I4.0). These systems must quickly adapt to fluctuations in demand, supply chain disruptions, and equipment failures. Digitalizing company assets is crucial for seamless communication and data integration across value chains. This transformation requires reorganizing machines and equipment using technologies such as the Internet of Things (IoT), data analytics, and artificial intelligence. Modern production systems, incorporating I4.0 concepts, rely on advanced architectures like RAMI4.0 for designing and implementing Digital Twins (DT).
For these systems to operate effectively in smart production environments, they must meet interoperability, communication, and standardization requirements. However, consistent application of standards, such as ISO 23247, remains a significant challenge. Managing intelligent production systems involves addressing complex structural, operational, and organizational issues. A methodical, integrated approach is essential to align strategic objectives with field operations.
This research aims to develop a structured approach for designing, developing, and implementing DT systems aligned with companies' strategic visions and commercial goals in manufacturing industries. The approach ensures traceability of design attributes, data interoperability, real-time synchronization, and model accuracy, adapting standard DT definitions to meet specific business needs.
The framework is divided into two main parts: (1) Developing a DT system on a smart platform to test various scenarios, such as production order management and rescheduling, considering the production line hierarchy; and (2) Validating the conceptual framework by designing a DT system prototype. This approach provides recommendations on how to develop and use DTs to enhance production system performance and strategic objectives, addressing the challenges of modern production systems.

« Contribution au développement de simulateur haptique pour l’apprentissage du geste chirurgical de l’insertion d’aiguille »

Doctorant : Benjamin DELBOS 

Laboratoire INSA : AMPERE

École doctorale : ED160 : EEA (Electronique, Electrotechnique, Automatique)

Au cours de cette doctorat, l'étude se concentre sur la simulation pour l'apprentissage du geste chirurgical d'insertion d'aiguille. Ce manuscrit explore plusieurs thématiques liées à la conception de simulateurs haptiques utilisant un retour de force via une interface haptique. Deux échelles de travail sont à distinguer.
La première concerne la reproduction haptique de l'interaction outil-tissu, visant à simuler les forces ressenties par le chirurgien lors de la pratique clinique. Bien que cette thématique ne soit pas spécifique à un geste particulier, elle s'applique à l'insertion d'aiguille, présente dans de nombreuses procédures chirurgicales. La problématique principale réside dans la modélisation et l’implémentation des forces d'insertion en simulation haptique, afin de reproduire fidèlement ces forces à travers une interface haptique. Parallèlement, une interface à retour de force a été conçue pour la simulation de l'insertion d'aiguille, optimisant ses performances tout en réduisant le coût des simulateurs, directement lié au coût de l'interface.
La seconde thématique concerne la reproduction de l'interaction chirurgien-patient, spécifique au geste de ponction ventriculaire, un acte courant en neurochirurgie. L'objectif est de fournir une représentation réaliste du geste pour améliorer l'apprentissage via la simulation haptique. Le simulateur développé associe un retour haptique, un retour visuel et un mannequin anatomique. Cette approche multimodale, absente de la littérature, vise à équilibrer la simulation haptique et physique, tout en garantissant la cohérence des retours sensoriels. Enfin, une méthodologie a été établie pour diversifier les cas d'études en simulation patient-spécifique, malgré les contraintes imposées par la présence du mannequin physique, en explorant des méthodes de génération de simulations adaptées.

« Strain Evolution and Mechanical Failure in SiOx-Graphite Blend Electrodes for Li-Ion Batteries: An Experimental and Simulation Study »

Doctorant : Abhilash VALISAMMAGARI

Laboratoire INSA : MATEIS

École doctorale : ED34 : Matériaux de Lyon

Silicon is identified as a promising material for negative electrodes in next-generation lithium-ion batteries due to its high lithium storage capacity of 3579 mAh/g, which is nearly 10 times higher than the conventional graphite electrode capacity of 372 mAh/g. However, silicon's practical use faces critical challenges due to its volumetric expansion (up to 300%) during lithiation and delithiation cycles. This leads to mechanical degradation, such as electrode delamination and particle detachment, which diminishes performance and cycle life. To address these issues, researchers have turned to silicon oxides (SiOx), which offer a balance between high capacity and cycling stability by reducing volumetric expansion. Although SiOx has a lower capacity than pure silicon, it still outperforms graphite electrodes. However, the mechanical challenges like particle detachment are still existing, but, to a lesser extent than pure silicon. The objective of this thesis is to observe and understand the impact of particle swelling on the overall structural integrity of the electrode. Particularly, focussing on the loss of connectivity in the electrode and to extract possible information for optimizing SiOx-containing electrodes. For this puropose, experimental investigations, including synchrotron tomography and digital volume correlation, were used to gain high-resolution insights into both global and local strain field distribution within the electrode. Later, considering the granular structure of the electrodes, a particle-based method called Discrete Element Method (DEM) was employed to represent the microstructure of the electrode, and considering the insights from the experimental investigation such as the evolution of strains at the electrode scale, the coupling of particle swelling was performed to reproduce the global strain. Finally, the corresponding impact at the electrode scale swelling and the resulting detachement of the particles was assesed by conducting connectivity study on the assembly.
 

« Use of additive manufacturing for functional rehabilitation »

Doctorant : Valentine DELBRUEL

Laboratoire INSA : MATEIS

École doctorale : ED34 : Matériaux de Lyon

Since 2017, Humanity and Inclusion has used Fused Filament Fabrication (FFF) to produce prosthetics and orthotics in low-income countries. The initial outcomes were promising, but reliance on imported PP filaments from Europe led to logistical issues. This project aims to recycle plastic waste into 3D-printing filament for local orthopedic device manufacturing in Togo. First, a study evaluated PET, PP, and TPU materials based on availability, recyclability, printability, and mechanical properties. PP was selected for its semi-rigidity, ensuring patient comfort and support. Second, the printability and properties of PP-PE blends from recycling plants were studied. Thermal and rheological analyses highlighted the most promising composition for FFF: a PP matrix with 30 to 50% HDPE. Satisfactory mechanical properties were obtained due to in-situ compatibilization during processing. Ultimately, recycled blends with 70% PP – 30% HDPE, sourced from post-consumer waste from food packaging and post-industrial waste from orthopedic sheet production scraps, were transformed into filament and 3D-printed into AFOs through an optimization of the processing parameters. Third, durability assessments examined the accelerated aging resistance of PP under Togo weather conditions. Recycled PP was sensitive to thermo- and photo-oxidation due to impurities and degraded stabilizers. However, 3D-printing limited process-induced degradation, showing promise for aging resistance. Finally, mechanical tests on a walking bench compared 3D- printed AFOs from virgin and recycled materials with thermoformed PP AFO. While the thermoformed AFO showed the highest resistance, 3D-printed AFOs exhibited similar resistance, with virgin AFOs showing ductile rupture and recycled AFOs showing brittle rupture, highlighting the potential of recycled materials. To conclude, the perspectives for humanitarian applications are discussed, emphasizing the potential of emerging techniques such as Fused Granular Fabrication, which could simplify the manufacturing process and reduce costs.

Experimental and theoretical analyses of the Rolling Contact Fatigue for indented surfaces

Doctorante : Aurore GOIGOUX

Laboratoire INSA : LAMCOS

École doctorale : ED162 : MEGA de Lyon (Mécanique, Energétique, Génie civil, Acoustique)

L’électrification des véhicules induit une modification des conditions opératoires des roulements présents dans les réducteurs. Cette application est caractérisée par une lubrification polluée.

Afin de développer des nouveaux matériaux efficacement, il est nécessaire de comprendre le mécanisme d’endommagement et d’en déduire les paramètres influents, ceci dans des conditions opératoires représentatives. Dans cet objectif, cette étude expérimentale et théorique est menée sur des roulements en 100Cr6 martensitique indentés par des particules dures. Le mécanisme d’endommagement est étudié basé sur deux approches : une caractérisation quantitative des indents et de leur endommagement et une caractérisation multi-échelle de la microstructure. Il est montré que les opérations de finition génèrent une fine couche plastiquement affectée à la surface qui n’évolue plus, ni après indentation, ni après fatigue, excepté sous l’épaulement de l’indent. Ainsi, l’épaulement est clé dans l’initiation de l’endommagement. D’abord, il se déforme et/ou s’use progressivement au cours de l’essai, son aspect de surface change et la zone rodée augmente. L’épaulement amont a un aspect de surface différent de celui aval, ce qui pourrait indiquer une déformation plastique plus avancée, expliquant la position préférentielle de la fissuration. Cette déformation engendre une plasticité avancée sous l’épaulement. Avec l’accumulation des cycles, une fissure s’y initie, certainement sur un défaut, comme l’interface carbure primaire/matrice. La propagation de la fissure n’est pas immédiate et consiste en deux processus distincts caractérisés par deux faciès de rupture différents. La fissure se propage d’abord dans une zone à la microstructure très fine, suggérant une propagation lente. La fissure modifie additionnellement la microstructure au-dessus d’elle, certainement par déformation et cisaillement entre les lèvres. La probabilité de fissuration est corrélée au temps d’essai, à la pression et au volume du creux de l’indent, mais pas à sa pente. L’influence du volume du creux pourrait s’expliquer par un volume d’épaulement plus important.

« Tomographic incompleteness maps and application to image reconstruction and stationary scanner design »

Doctorant : Matthieu LAURENDEAU

Laboratoire INSA : CREATIS

École doctorale : ED160 : EEA (Electronique, Electrotechnique, Automatique)

Computed tomography (CT) is one of the most commonly used modality for three-dimensional (3D) imaging in the medical and industrial fields. In the past few years, new X-ray sources have been developed based on carbon nanotube (CNT) cathodes. Their compact size enables the design of a new generation of multi-source CT scanners. In contrast to traditional systems with a single moving source, these scanners often adopt stationary architectures where multiple sources are static. It would benefit both industry with cheaper and motionless systems and medical applications with light-weight and mobile scanners which could be brought to emergency sites. However, this type of scanner uses a fewer number of measurements, known as projections, and may acquire data with a limited range of angles, leading to well-known image reconstruction challenges. This thesis focuses on the design of such stationary CT scanners. Three axes of study are investigated.

The first contribution is the development of an object-independent metric to assess the reconstruction capability of a given scanning geometry. Based on Tuy's condition, the metric evaluates local tomographic incompleteness and is visualized through 3D vector field maps. It is further extended to handle truncated projections, improving its applicability to real-world configurations. The metric enables ranking different geometries, predicting image quality reconstruction, and identifying the origin of geometric artifacts. It is applied to a variety of geometries, including existing scanners.

The second is a novel local regularization method to address limited-angle reconstruction challenges. The method employs a directional total variation (DTV) regularizer whose strength and directional weights are adaptively selected at each voxel. The weights are determined based on the previously introduced metric. Two approaches for directional weights are explored: ratio-based weighting relative to image axes and ellipse-based weighting. The reconstruction algorithm is evaluated in both 2D and 3D simulations, considering noiseless and noisy data, as well as real data.

The third is a tool for optimizing the geometry of CT scanners. Given a fixed number of sources and the surface area available for their positions, the tool optimizes the placement of sources based on the proposed metric. Several state-of-the-art optimization algorithms are implemented and tested on simple 2D and 3D scenarios.

« Noise annoyance in open-plan offices and occupant fatigue: a study on the influence of age-related hearing loss »

Doctorant : Nicolas Fernando PONCETTI

Laboratoire INSA : LVA
École doctorale : ED162 : Mécanique, Énergétique, Génie Civil, Acoustique

Open-plan offices are common in the tertiary sector, yet occupants often complain about noise, particularly from co-worker conversations. This issue can differently affect normal hearing people and those with presbycusis. This study examines the impact of mild hearing loss (early-stage presbycusis) on performance, fatigue, and perceived workload, with a focus on the effect of irrelevant speech. An analysis of the decrease in performance on a serial recall task as a function of the intelligibility level of irrelevent speech was conducted with young, normal-hearing subjects under two auditory conditions: with and without a hearing loss simulator, as well as with hearing-impaired elderly subjects. Participants were exposed to five noise conditions and silence. Subjective intelligibility was also measured. The results showed a minor, non-significant difference in decrease of performance between normal-hearing and hearing-impaired participants. The hearing loss simulator produced results comparable to those of the older group, validating its efficacy. A second experiment involving prolonged noise exposure was conducted to examine factors such as fatigue and workload, which are challenging to evaluate in shorter experiments like the first one. In this experiment, a working day was simulated in an open-plan office, where participants performed clerical tasks while exposed to irrelevant speech. The results indicate that the intelligibility of the noise does not appear to significantly impact perceived fatigue and workload. Again, no notable differences were observed between the two groups studied.