ED Mathématiques et Informatique
Reconstruction of the electrical activation sequence of the heart from non-invasive measurements
by Emma LAGRACIE (IMB - Institut de Mathématiques de Bordeaux)
The defense will take place at 14h00 - Ada Lovelace Salle Ada Lovelace, Centre Inria de l'université de Bordeaux, 200 avenue de la vieille tour, 33405 Talence
in front of the jury composed of
- Yves COUDIERE - Professeur - Université de Bordeaux - Directeur de these
- Didier AUROUX - Professeur - Université Côte d'Azur - Rapporteur
- Stephanie LOHRENGEL - Professeure - Université de Reims - Rapporteur
- Lisl WEYNANS - Professeure - Université de Bordeaux - CoDirecteur de these
- Jean-François AUJOL - Professeur - Université de Bordeaux - Examinateur
- Laura BEAR - Chargée de recherche - Université de Bordeaux - Examinateur
- Annabelle COLLIN - Professeure - Université de Nantes - Examinateur
- Jérémi DARDE - Maître de conférences - Université Paul Sabatier - Examinateur
Cardiac arrhythmias are among the leading causes of death worldwide. While some can be detected by clinical tests such as electrocardiograms (ECGs), others occur suddenly in patients considered healthy and can sometimes lead to sudden death. A key question is therefore whether there are any warning signs of these events in the electrical signals from the torso surface and, if so, how to identify them. In particular, during heart contractions, the cells are synchronized by an electrical activation wave that travels throughout the heart. The activation sequence of the heart cells can then provide cardiologists with valuable information about the origin of possible rhythm disorders. The inverse problem of cardiac electrophysiology, or electrocardiographic imaging (ECGi), aims to reconstruct the electrical activity of the heart, and in particular the activation sequence, from non-invasive measurements of electrical potential on the surface of the torso. This problem is mathematically ill-posed in the sense of Hadamard, which makes it particularly difficult to solve. Studying the properties of this inverse problem and developing new methods for solving it is a major challenge for improving and systematizing the detection of cardiac arrhythmias. In this context, this thesis proposes new approaches to addressing the problem of electrocardiographic imaging. Classically, the ECGi problem is formulated as a constrained optimization problem, requiring the satisfaction of a partial mathematical model of the heart's electrical activity, called the "source model". Constraint terms, called "regularization", are also added to ensure the invertibility and stability of the minimization problem. The choice of source model, as well as the constraints imposed on the electrical potentials and voltages on the heart modify significantly the properties of this inverse problem. In this thesis, we first focused on describing the inherent difficulties of the inverse problem in cardiac electrophysiology. We presented several formulations of the problem, from source models describing the underlying electrophysiology to the mathematical and numerical methods used for its resolution. We then developed a new source model for ECGi. The "depth-averaged" model was first established in two dimensions for simplified geometries, then heuristically extended to three dimensions under the name "epicardial model". This model couples a surface transmembrane voltage and a surface extracellular potential with a volume extracardiac potential in the torso, while accounting for flux exchanges between the heart and the torso. It thus offers more diverse modelling possibilities than the models commonly used in ECGi. Certain properties of the epicardial model were used to numerically study the inverse problem in three dimensions. The presence of surface conductivities made it possible to evaluate the impact of the a priori integration of cardiac fibres. This framework also allowed for the introduction of a more physiologically realistic regularisation, based on the total variation of the transmembrane voltage, and for the comparison of different methods for extracting activation sequences from the reconstructed data. In a final exploratory study, we proposed a new method for solving the inverse problem, based on Bayesian theory, combining a simplified model of cardiac electrical activation with a particle filtering technique. This approach makes it possible to reconstruct the activation sequence while explicitly incorporating a degree of uncertainty, thus paving the way for a probabilistic interpretation of electrocardiographic imaging results.
Cost of controllability of the linearized equations of fluid mechanics
by Vincent LAHEURTE (IMB - Institut de Mathématiques de Bordeaux)
The defense will take place at 13h00 - Salle de Conférences A33, 351 Cr de la Libération, 33400 Talence
in front of the jury composed of
- Franck SUEUR - Full professor - Université du Luxembourg - Directeur de these
- Camille LAURENT - Directeur de recherche - Université de Reims - Rapporteur
- Pierre LISSY - Chaire de professeur junior - Ecole des Ponts ParisTech - Rapporteur
- Franck BOYER - Professeur des universités - Université de Toulouse - Examinateur
- Marius TUCSNAK - Professeur - Université de Bordeaux - Examinateur
- Roberta BIANCHINI - Chargée de recherche - Istituto per le Applicazioni del Calcolo Mauro Picone - Examinateur
This thesis deals with the control theory of deterministic partial differential equations, particularly linear equations or systems of equations arising from fluid mechanics. It focuses on two distinct problems. In the first part, we explore the control of metastable states through the study of two one-dimensional scalar parabolic equations: the Burgers and Allen-Cahn equations. These two equations admit stationary states—respectively shocks and consecutive transition layers—for which small perturbations require a long return time to equilibrium in the small diffusion regime, with a reaction term taken proportionally large in the Allen-Cahn case. Through a detailed analysis of all eigenvalues and eigenfunctions, we show that the linearized operators can nonetheless be controlled with a uniform control cost. In the case of the Allen-Cahn equation, we establish a necessary and sufficient condition of geometric nature on the control's support. In the second part, we study the controllability of initial data localized in phase space for hyperbolic-type differential or pseudodifferential systems in multiple spatial dimensions. We show that in the high-frequency regime, the control cost can be estimated using systems of ordinary differential equations known as bicharacteristic-amplitude systems, by tracking the evolution of the local energy tensor. Furthermore, we show that by applying Hilbert's uniqueness method, one can construct approximate explicit controls with asymptotically optimal cost, based on the optimal control for the associated ODE.
ED Droit
The criminal responsibility of minors: a comparative, analytical and critical study between French and Kuwaiti legislation.
by Fajer ALSHAMMARI (INSTITUT DE SCIENCES CRIMINELLES ET DE LA JUSTICE)
The defense will take place at 14h30 - salle de thèses 16 rue Leon Duguit 3600 Pessac
in front of the jury composed of
- Olivier DECIMA - Professeur - Université de Bordeaux - Directeur de these
- Muriel GIACOPELLI - Professeure - Université d'Aix-Marseille - Rapporteur
- Husain BUARAKI - Professeur - Université du Kuweit - Rapporteur
- Adeline GOUTTENOIRE - Professeure - Université de Bordeaux - Examinateur
The thesis focuses on the specificity of the criminal responsibility of minors in French and Kuwaiti legislation, emphasizing in the first part the degree of substantial and procedural autonomy of the regulation of the criminal responsibility of minors in both legislations, based on a comparative analytical method, to understand the particular conditions and independent penal systems governed by the principle of rehabilitation rather than punishment, and the principle of mitigating penalties; Special procedures for the enforcement of juvenile sentences. Secondly, the second part of this study presents in a critical and comparative manner the limited material and procedural independence of this criminal responsibility in the two legislations, to highlight the legislative shortcomings of the two legislations and to add legal proposals that contribute to the development and strengthening of the independence of the criminal responsibility of minors from the criminal responsibility of adults. At the end of the study, the aim is to develop the criminal legislative systems for minors in France and Kuwait to combat juvenile delinquency on the one hand and to deal with their exposure to delinquency on the other.
ED Sciences de la Vie et de la Santé
Implication of polyunsaturated fatty acid (PUFA) biostatus in dopamine transmission-relatedreward processing deficits
by Lola HARDT (Nutrition et Neurobiologie Intégrée)
The defense will take place at 14h00 - Amphi Broca 146 Rue Léo Saignat, 33000 Bordeaux, Centre Broca
in front of the jury composed of
- Sébastien CARNICELLA - Directeur de recherche - Grenoble Institut des Neurosciences – Inserm U1216 – Université Grenoble Alpes - Rapporteur
- Pauline BELUJON - Maîtresse de conférences - Laboratoire de Neurosciences Expérimentales et Cliniques - Rapporteur
- Emmanuel VALJENT - Directeur de recherche - Inm - Institute For Neurosciences Of Montpellier - Examinateur
- Cecilia FLORES - Full professor - The Douglas Research Centre - Examinateur
Distinctly characterized psychiatric diseases such as major depression, bipolar disorder, and schizophrenia exhibit common symptoms, including reward processing deficits linked to a dysfunction of meso-cortico-limbic dopaminergic (DA) transmission suggesting common underlying mechanisms. Interestingly, numerous studies have described a decrease in n-3 polyunsaturated fatty acids (PUFA) in a subpopulation of patients with these disorders (Conklin et al., 2010; Messamore and McNamara, 2016) as well as that suggested that DA transmission is particularly sensitive to PUFA biostatus in preclinical models (Chalon et al. 2006, Ducrocq et al. 2020). However, a causal link remains to be established. We were able to show that n-3 PUFA deficiency in mice leads to deficits in motivational tasks as well as impulsive tendencies in a choice impulsivity task compared to controls indicating reward processing impairments. Normalization of PUFA biostatus in DA neurons specifically with an iFATxDAT-cre transgenic mouse model was sufficient to restore behavioural performance confirming a causal link between dopaminergic n-3 PUFA deficiency and deficits in reward processing. Fiber photometry was used to show that these deficits were accompanied by a change in transmission dynamics in the meso-cortico-limbic circuit. These changes appear to be due to neuroanatomical alterations observed from immunofluorescence analysis comparing fibre density in the NAc and mPFC. We need to further study the mechanisms underlying DA alterations in order to better understand the etiology of psychiatric illnesses and develop better treatment for these illnesses.
ED Sciences Physiques et de l'Ingénieur
Cognitive Warfare and Influence on Decision-Makers: A Methodological Approach to Designing a System for Supporting Situational Awareness and Decision-Making
by Marie MORELLE (Laboratoire de l'Intégration du Matériau au Système)
The defense will take place at 10h00 - O108 ENSC, 109 avenue ROUL, 33405 Talence Cedex
in front of the jury composed of
- Jean-Marc ANDRE - Professeur des universités - Bordeaux INP - ENSC, laboratoire IMS - Directeur de these
- Laurent 'Mary' CHAUDRON - Directeur de recherche - ONERA - Rapporteur
- Mathieu VALETTE - Professeur des universités - INALCO - Rapporteur
- Anne LEHMANS - Professeure des universités - Université de Bordeaux, INSPE, Laboratoire IMS - Examinateur
- Cléo COLLOMB - Maîtresse de conférences - Université Paris-Saclay - Examinateur
- Julien CEGARRA - Professeur des universités - Institut National Universitaire Champollion - Examinateur
- Benoît LE BLANC - Professeur des universités - ENSC, Bordeaux INP - Examinateur
Cognitive warfare aims to influence, modify and direct human thought and information processing. It employs various technological and digital means, such as social networks, information dissemination, cyber-attacks and NBIC technologies, as well as combinations of these methods. Cognitive warfare targets the human cognition and mind. It targets mental representations and cognitive processes to sow doubt, prevent or influence decisions, undermine the adversary's will, or manipulate how people perceive and interpret information without their awareness. The goal is to gain a tactical or strategic advantage through destabilization, erosion of trust, acquisition of desired information or decisions, inhibition of expected behaviors, or manipulation of public opinion. As emphasized by the French Chief of the Defense Staff, General Thierry Burkhard, it is about “winning the war before the war”. Recent and less recent events highlight the importance of recognizing the reality and significance of cognitive warfare actions and the manipulation of information and decision-making, in order to protect against them by being proactive against agents of influence who employ those tactics. Thus, through this work, we seek to contribute to this awareness by providing conceptual elements of understanding, examples, and potential solutions. The objective of this thesis is to lay the foundations for a decision support system that offers detection of cognitive warfare actions, countermeasures and offensive actions to correct the situation. To meet these requirements, we structured our work into five main steps: 1. A conceptual approach to cognitive warfare: definitions, targets and actors, tools, examples and challenges. 2. A study of biases and influences on decision-making and methods to protect against them, particularly with decision support systems. 3. An experiment aimed at determining the factors influencing decision-making, particularly those that make a text more credible and thus give it a greater potential for influence. After reviewing the literature, which allowed us to list a large number of text credibility factors, and then reducing these factors, we conducted an online card sorting exercise on the 12 final selected factors to determine which ones confer the most credibility to a text. 4. A step to determine the criteria for qualifying cognitive warfare targets: we propose a list of 5 criteria to study in order to determine if the targeted individual is relevant, particularly based on their potential influence on the targeted decision and their vulnerabilities. 5. The development of a system for real-time detection and influence of strategies. This step is the subject of a second experiment, conducted using a strategy game. We used the decision tree principle of the ANTICIPE system developed by THALES to detect players' strategies in real-time and propose solutions to influence their strategy. This step builds on the findings of the first experiment. Based on the results of these different steps, we propose a methodology to adapt the ANTICIPE system to make it a decision support tool in the context of cognitive warfare. The results of this thesis in cognitive engineering lay the foundation for building a technological system that contributes to situational awareness in a cognitive warfare context and assists its user in selecting relevant targets and solutions for a targeted cognitive response.