ED Mathématiques et Informatique
Local structure in combinatorics: reconstruction, saturation, spreadness and universality
by Paul BASTIDE (LaBRI - Laboratoire Bordelais de Recherche en Informatique)
The defense will take place at 14h00 - Amphi LaBRI LaBRI, Domaine universitaire, 351, cours de la Libération, 33405 Talence, France
in front of the jury composed of
- Marthe BONAMY - Chargée de recherche - Université de Bordeaux - Directeur de these
- Imre LEADER - Professeur - University of Cambridge - Rapporteur
- Gwenaël JORET - Professeur - Université Libre de Bruxelles - Rapporteur
- Pawel PRALAT - Professeur - Toronto Metropolitan University - Rapporteur
- Mireille BOUSQUET-MELOU - Directrice de recherche - Université de Bordeaux - Examinateur
- Dana RON - Professeure - Tel Aviv University - Examinateur
- Frédéric MAGNIEZ - Directeur de recherche - IRIF - Examinateur
- Carla GROENLAND - Professeure assistante - TU Delft - CoDirecteur de these
This thesis explores local structures in combinatorics, focusing on understanding how local configurations influence the global properties and structures of combinatorial objects. This thesis is divided into four parts, each investigating different problems related to local structures: distance reconstruction, poset saturation, spread embedding, and universal structures. In the chapter related to distance reconstruction, we seek to reconstruct an unknown graph using local information. We only have access to an oracle providing the shortest path distances between pairs of vertices. We study this problem for different classes of graphs, improving both the best-known lower bounds and upper bounds in various cases. In particular, we provide an optimal algorithm for reconstructing trees and a near-optimal algorithm for reconstructing graphs without long induced cycles. Then, we study poset saturation, introduced by Katona and Tarjan in 1981. This concept extends Turán's seminal work in extremal graph theory. A P-saturated family is a maximal family that avoids any substructure locally isomorphic to P (i.e., avoids P as an induced subposet). We study the saturation number of a poset P, defined as the minimum size of a P-saturated family included in the hypercube of dimension n. Despite substantial work on this problem in recent years, the saturation number is only known exactly for small posets, and its possible behaviors are still largely unknown. In this thesis, we will show that an extension of a lemma from Lehman and Ron allows us to compute exactly the saturation number of the antichain of size k. We also prove the first general upper bound on the possible behavior of the saturation number for any poset P. In the chapter on spreadness, we study the distribution of spanning trees in dense graphs. It might seem, at first, far from local, as a ``spanning'' structure is by definition global, but the key technique we developed to construct these global spanning structures goes through the subdivision into multiple local substructures. Via this novel method, we are able to give a simpler and more flexible proof of the existence of spread embeddings for bounded-degree trees. In particular, our approach does not use Szemerédi's Regularity Lemma. Finally, we study universal structures. Given a family F of combinatorial objects and an integer n, another object U is said to be universal if it contains every element of F of size n as a local substructure. We call such a structure "faithful" when U is also part of F. In this chapter, we study the minimum size of faithful universal graphs for minor-closed classes of graphs as well as the size of universal posets for the family of all posets.
ED Sciences de la Vie et de la Santé
Macro and micro anatomy of the left atrium and pathophysiological implications in atrial arrhythmias
by Anaïs DELGOVE (Centre de recherche Cardio-Thoracique de Bordeaux)
The defense will take place at 15h00 - Amphithéatre IHU Liryc Hôpital Xavier Arnozan Avenue du Haut Lévêque 33604 Pessac cedex
in front of the jury composed of
- Olivier BERNUS - Professeur - Université de Bordeaux - Directeur de these
- Dominique LIGUORO - Professeure des universités - praticienne hospitalière - Laboratoire d'Anatomie - Ecole de chirurgie - Université de Bordeaux - Examinateur
- Yohann RENARD - Professeur des universités - praticien hospitalier - Université de Reims - Examinateur
- Laure CHAMP RIGOT - Maîtresse de conférences - praticienne hospitalière - Université de Caen - Examinateur
The anatomy, embryology and pathophysiology of left atrial rhythm disorders are intimately linked. The oblique vein of the left atrium (OVLA) is an embryonic remnant of the left anterior cardinal vein. It persists as a more or less permeable epicardial vein, terminating in the coronary sinus. It is surrounded by myocardial fibers that can create or maintain atrial fibrillation. The aim of this work was to study the anatomy of the left atrium, and more specifically the oblique vein of the left atrium, and its relationship with the surrounding myocardium. A review of the literature on the subject, covering both anatomical knowledge of the region and techniques for studying this anatomy in vivo and ex vivo, showed that no article described, precisely and in situ, the arborization of the oblique vein of the left atrium. A protocol for the ex vivo tissue preparation of human hearts using micro-CT scanners was developed to visualize both the vein of interest selectively injected with contrast medium and the various components of the left atrial tissue on high-resolution acquisitions. The study of 18 human hearts using this protocol yielded results on the size and position of the OLVA ostium, its arborization type and the location of its main collaterals, as well as the theoretical myocardial surface drained. CT scans and histological confirmation showed a variable interposition of fatty tissue between the myocardial fibers surrounding the OVLA and the compact myocardium. This fatty interposition could impact the results of atrial fibrillation ablation techniques by protecting epicardial myocardial fibers from radiofrequency currents or cryotherapy. We therefore conducted a study of the relationship between the OVLA and the myocardial fibers accompanying it, and the fatty tissue isolating it from the compact myocardium. This study was carried out both on ex vivo human micro-CT samples and on open-access imaging data from the Human Organ Atlas® (whole hearts imaged by hierarchical phase-contrast tomography).
ED Sciences Physiques et de l'Ingénieur
Development of a Decision Support Tool to Facilitate the Implementation and Management of a 4.0 Automated Factory for Textile Production.
by Amanda DA MOTA BERNAR (ESTIA-Recherche)
The defense will take place at 14h00 - Amphi 31 Technopole Izarbel 90 Allée Fauste d'Elhuyar, 64210 Bidart
in front of the jury composed of
- Jérémy LEGARDEUR - Professeur - Université de Bordeaux - Directeur de these
- Mickael GARDONI - Professeur - ETS Montréal - Rapporteur
- Hélène CHANAL - Professeure - Université Clermont Auvergne - CoDirecteur de these
- Fréderic SEGONDS - Professeur des universités - Arts et Métiers - Rapporteur
- Philippe GIRARD - Professeur des universités - ISAE Supmeca - Examinateur
The textile industry has undergone major transformations in recent decades, characterized by the massive offshoring of production to low-labour-cost countries. This phenomenon has led to a loss of competitiveness among European manufacturers and created several challenges, including significant environmental and social impacts driven by the growing consumer demand for cheap and fast products, particularly under the influence of fast fashion. In response, initiatives aimed at reshoring textile production in Europe while addressing sustainability goals and new regulations, such as the AGEC Law on the Circular Economy, have emerged. Within this context, the adoption of Industry 4.0 technologies has become essential for restoring the sector's competitiveness. This thesis is positioned within this dynamic and proposes a decision-making methodology for the implementation of Industry 4.0 technologies in French textile factories. It was developed in collaboration with Petit Bateau, a major player in the textile industry, and presents a structured methodological framework for decision-making and the effective integration of 4.0 concepts and systems into production processes. The work is structured around several key stages. The first phase involves an analysis of the current situation, identifying the specific challenges of the sector and the technologies available within the company. The second phase focuses on an empirical and inductive study to analyse the socio-technical dynamics within the factory. The third phase consists of designing a methodological framework to guide the deployment of Industry 4.0 technologies. This framework is then tested and validated through two case studies within a pilot project, where the phases of the methodology are implemented in real-world situations. Finally, an analysis of the results allows for the identification of improvement levers and the adjustment of the methodology for broader application. The originality of this thesis lies in the development of a systematic and structured methodology, articulated around five main phases: Systemic Vision, Strategic Decisions, Implementation, Analysis, and Production Launch. Each phase considers the specificities of the textile sector and the strategic priorities of the company, using advanced analysis tools as well as artificial intelligence technologies to optimize decision-making. This methodology was validated through concrete tests conducted at the Petit Bateau and Lacoste factories. The experimental results show that the methodology enables the structuring of needs, prioritization of Industry 4.0 projects, and efficient selection of technologies adapted to the specific needs of the textile sector, reducing production costs, improving flexibility, and facilitating the acceptance of new technologies by employees. Team support and transparent communication were key factors in overcoming resistance to change and promoting the adoption of the proposed solutions. This thesis also opens future research perspectives, particularly on the impact of digital transformations on worker well-being. Industry 5.0, which places humans at the centre of industrial processes, could benefit from an analysis of the influence of new technologies on operator motivation and their quality of life at work. Furthermore, the methodology developed, although initially designed for the textile sector, could be adapted to other manufacturing industries or even tertiary sectors, to validate its flexibility and applicability. Keywords: Industry 4.0, Decision-making methodology, Textile reshoring
ED Sociétés, Politique, Santé Publique
Exposure to ultraviolet radiation and estimation of the impact on skin and eye health
by Bouchra AMARI (Bordeaux Population Health Research Center)
The defense will take place at 16h00 - Amphi Louis Inserm "Bordeaux Population Health Research Center" (BPH) U1219, Université de Bordeaux, ISPED, 146 rue Léo Saignat 33076 Bordeaux CEDEX
in front of the jury composed of
- Cécile DELCOURT - Directrice de recherche - Université de Bordeaux, INSERM, Centre de recherche Bordeaux Population Health (BPH), U1219 - CoDirecteur de these
- Jean-François KOROBELNIK - Professeur des universités - praticien hospitalier - Service d'Ophtalmologie, Hôpital Pellegrin, CHU de Bordeaux - Examinateur
- Corinne DOT - Professeure des universités - praticienne hospitalière - Hôpital universitaire Édouard-Herriot, Lyon - Rapporteur
- Pascal GUENEL - Directeur de recherche - Inserm, Centre de Recherche en Epidemiologie et Santé des Populations (CESP), Hôpital Paul Brousse - Rapporteur
Ultraviolet radiation (UVR), primarily of solar origin, plays an ambivalent role in human health. While essential for certain biological functions, such as vitamin D synthesis, UVR is classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). Prolonged or excessive exposure is a well-established risk factor for skin cancers, as well as for ocular diseases such as cataract and, possibly, age-related macular degeneration (AMD). Despite its public health significance, and although several epidemiological studies suggest an association between occupational UVR exposure and the occurrence of cataract or skin cancers, most of the available evidence suffers from notable methodological limitations, including small sample sizes, exposure misclassification, and lack of robust retrospective assessments. Regarding AMD, available studies remain limited, and their findings are inconsistent. The main objective of this thesis was to evaluate the impact of chronic UVR exposure on eye and skin health, through two complementary approaches: residential exposure and occupational exposure. The first axis relied on data from 963 participants in the Alienor cohort, a prospective study conducted among individuals over 73 years of age residing in the Bordeaux area. Residential UVR exposure was estimated with high precision by reconstructing participants' lifetime address history and linking it to ambient UVR irradiance data from the EuroSun satellite. A significant association was observed between intermediate levels of cumulative ambient UVR exposure and an increased risk of early AMD. In contrast, no clear dose-response relationship was identified, and UVR exposure was not significantly associated with advanced AMD. The second axis was based on the national Constances cohort, in which 93,000 French adults meeting the inclusion criteria were selected among participants who provided detailed occupational histories. Occupational UVR exposure was estimated using Canadian job-exposure matrices (CANJEM and UVJEM), allowing the reconstruction of cumulative exposure across the entire working life. The weighted prevalence of occupational UVR exposure was generally low (around 2%) but higher in certain subgroups, particularly men, blue-collar and agricultural workers, rural residents, and individuals with lower education or income. Despite these social and occupational disparities in exposure, no statistically significant associations were observed between occupational UVR exposure and the risk of cataract surgery, neovascular AMD, or skin cancers (melanoma, basal cell carcinoma, and squamous cell carcinoma). This lack of association may be explained by relatively low exposure levels in the general population and highlights the need to target populations with higher exposure levels to better assess UVR-related occupational health risks. The findings suggest a possible effect of residential UVR exposure on the incidence of early-stage AMD. Still, additional longitudinal studies are needed to confirm this association and to investigate potential effects on advanced stages. Retrospective exposure assessment remains one of the main methodological challenges in occupational epidemiology. Although CANJEM and UVJEM provide useful tools for estimating UVR exposure, their accuracy could be improved by using locally adapted approaches and individual dosimetry data. Finally, the lack of information on protective behaviors also represents a significant limitation in interpreting results.