ED Mathématiques et Informatique
Isometric-universal graphs
by Edgar BAUCHER (LaBRI - Laboratoire Bordelais de Recherche en Informatique)
The defense will take place at 14h00 - Amphithéâtre du LaBRI, Domaine universitaire, 351 Cr de la Libération, 33405 Talence, France.
in front of the jury composed of
- François DROSS - Maître de conférences - LaBRI, Université de Bordeaux - Directeur de these
- Gwenaël JORET - Professeur - Université libre de Bruxelles - Rapporteur
- Louis ESPERET - Directeur de recherche - G-SCOP Grenoble - Rapporteur
- Carla GROENLAND - Assistant professor - TU Delft - Examinateur
- Claire HILAIRE - Associate Professor - LIMOS/ISIMA, University Clermont-Auvergne - Examinateur
- Philippe DUCHON - Professeur - LaBRI, Université de Bordeaux - Examinateur
Graphs are one of the most common data structures to store information in computer science. When it comes to storing, also comes the question of storing efficiently. This thesis presents research on graphs that store other graphs as efficiently as possible. More precisely, we study different graph families, and for each one of these families, we look for graphs that store all graphs in the family in addition to preserving their metric structures. Such graphs are called isometric-universal graphs, and this manuscript aims to find the smallest of them. By smallest we mean those that take the least space to store. We first explore structural and algorithmic properties of isometric-universal graphs. Then, we identify connections with a related research area, namely distance labelling schemes. These are data structures that encode graphs and also preserve their metric structures, however, unlike isometric-universal graphs, distance labelling schemes are not graphs. We also focus on several specific graph families. We attempt to design isometric-universal graphs for them with the smallest size theoretically achievable. This implies proving lower bounds on their sizes that are inherent to their structures. We pay particular attention to families of graphs with simple structures, like trees, forests, or general graphs. Finally, we study algorithmic questions regarding isometric-universal graphs for these graph families, and we prove some NP-Completeness results.
Development of an Edge architecture for micromobility and intermodality
by Rania SWESSI (LaBRI - Laboratoire Bordelais de Recherche en Informatique)
The defense will take place at 10h00 - Amphithéâtre du LaBRI LaBRI Domaine universitaire 351 Cours de la Libération 33405 Talence, France
in front of the jury composed of
- Mohamed MOSBAH - Professeur - Université de Bordeaux - Directeur de these
- Yohan DUPUIS - Directeur de recherche - CESI LINEACT Paris - Rapporteur
- Saadi BOUDJIT - Professeur - Université de Rouen Normandie - Rapporteur
- Akka ZEMMARI - Professeur - Université de Bordeaux - Examinateur
- Imen JEMILI - Maîtresse de conférences - Université de Carthage - Examinateur
Shared micro-mobility systems have become an essential component of urban transportation, offering flexible and sustainable solutions for short-distance travel. However, their large-scale deployment raises several operational challenges, including parking disorder in free-floating systems, demand–supply imbalance (i.e., vehicles are not available where and when needed), high fleet management costs, increased safety risks, and limited integration with public transportation. This thesis investigates how artificial intelligence techniques can address these challenges by proposing data-driven approaches to improve the efficiency and safety of shared micro-mobility systems. First, parking disorder in free-floating systems is addressed through a multi-layer clustering approach that identifies demand hotspots and supports optimal placement of virtual stations. These designated spaces, implemented without physical infrastructure, help reduce improper parking and enhance spatial organization. To support efficient system operation, a demand forecasting approach is proposed to mitigate demand–supply imbalance. It estimates vehicle requirements across locations and time, supporting fleet redistribution. The approach is also designed to generalize to other operational configurations, including physical dock-based and free-floating systems. To ensure scalability while reducing communication overhead and latency, an Edge-enabled architectural design is introduced, allowing decentralized data processing and faster decision-making. Building on these contributions, operational decisions are optimized in real-time using deep reinforcement learning. A first framework focuses on fleet management by recommending alternative nearby drop-off zones and involving users in the redistribution process. It integrates predicted demand and vehicle battery levels to maintain vehicle availability while reducing operational costs by limiting manual redistribution and facilitating the aggregation of low-battery vehicles. A second framework addresses safety by recommending safer drop-off zones based on urban factors such as traffic conditions, cycle lane availability, intersection density, lighting, and congestion. Finally, to improve first- and last-mile accessibility, this thesis extends the demand forecasting framework to intermodal contexts, with the aim of enhancing vehicle availability in areas connected to public transit stops. It combines local public transport demand with spatial and contextual factors that shape transportation integration patterns. A hybrid graph-based deep learning framework is employed to model these relationships and to better represent urban mobility patterns. All these contributions are integrated into an end-to-end smart management system enabling real-time and user-aware decision-making. Experiments conducted on real urban case studies demonstrate the effectiveness of the proposed system, including the accurate identification of virtual stations, reliable demand prediction, and improved vehicle allocation through drop-off zone recommendations. Overall, this work contributes to the development of shared micro-mobility systems that are more efficient, safer, and more sustainable, and provides useful insights for researchers and urban planners aiming to improve mobility services.
ED Sciences Chimiques
Study of the effect of local environment on molecular rotors in macromolecular systems
by Mingshan CHI (Laboratoire du Futur)
The defense will take place at 14h00 - Amphithéatre 115 Avenue du Dr Albert Schweitzer 33600 Pessac Centre de Recherche Paul Pascal
in front of the jury composed of
- Yaocihuatl MEDINA-GONZALEZ - Directrice de recherche - Université de Bordeaux - Directeur de these
- Eric FREYSSINGEAS - Maître de conférences - École normale supérieure de Lyon - Rapporteur
- Jean-François LAHITTE - Maître de conférences - Université Toulouse 3 - Rapporteur
- Pierre LIDON - Maître de conférences - Université de Bordeaux - CoDirecteur de these
- Annie COLIN - Professeure - ESPCI - Examinateur
- Olivier MONDAIN-MONVAL - Professeur - Université de Bordeaux - Examinateur
Molecular rotors are fluorescent probes whose fluorescence properties depend on the resistance of their surrounding medium during intramolecular rotation, and their fluorescence lifetime is commonly related to viscosity through the Förster-Hoffmann relation. However, this relation generally uses macroscopic viscosity to represent the resistance experienced during intramolecular rotation, while the lifetime represents the immediate environment sensed by the rotor. This thesis investigates how this local environment should be represented in polymer systems. In binary PEG/water solutions, the BODIPY-based molecular rotor first showed a relation between viscosity and fluorescence lifetime when viscosity was changed by PEG concentration. However, when PEG molecular weight was changed, solutions with similar macroscopic viscosities showed different lifetimes. In a shear-thinning system, the lifetime also remained almost constant under shear flow although the macroscopic viscosity changed. These results showed that macroscopic viscosity alone cannot fully describe the resistance experienced by the rotor. Ternary PEG/water mixtures were then used to introduce an additional controllable parameter at fixed global mass fraction. The analysis of viscosity, lifetime and specific volume showed that the fluorescence lifetime is better described by local free volume. The fluorescence lifetime of molecular rotors was finally extended to PVA/PEG solid films. In this system, the lifetime increased with the degree of crystallinity, which suggested that the rotor sensed the local distribution of amorphous and crystalline regions. Overall, this thesis shows that the molecular rotor's fluorescence lifetime should be understood as the response to its local environment, rather than as a direct measurement of macroscopic viscosity.
ED Sciences de la Vie et de la Santé
Nanoscale organization and plasticity-dependent remodeling of glutamate receptors in striatal synapses and its implications in Shank3-associated ASD
by Meera CHANDRA (Institut Interdisciplinaire de Neurosciences)
The defense will take place at 14h00 - Amphi Centre Broca IINS Université de Bordeaux Centre Broca Nouvelle-Aquitaine 146, rue Léo Saignat CS 61292 Case 130 33076 Bordeaux Cedex
in front of the jury composed of
- Eric HOSY - Directeur de recherche - Université de Bordeaux - Directeur de these
- Julie PERROY - Directrice de recherche - Institut de Génomique Fonctionnelle - Rapporteur
- Cécile CHARRIER - Directrice de recherche - Institut de Biologie de l'École Normale Supérieure - Rapporteur
- Laurent VENANCE - Directeur de recherche - Centre interdisciplinaire de recherche en biologie (CIRB), College de France - Examinateur
- Jérôme BAUFRETON - Directeur de recherche - L'Institut des Maladies Neurodégénératives (IMN) - Examinateur
Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental condition characterized by deficits in social communication, repetitive behaviors, and restricted interests. Large-scale exome and genome sequencing have converged with high confidence to identify risk genes that encode proteins associated with synaptic assembly, maturation, and functions. Among the most prominent are scaffolding proteins of the Shank family (Shank1-3), neuroligins, neurexins, and SYNGAP1. These genes regulate the nanoscale architecture of excitatory post-synapses by anchoring glutamate receptors, controlling actin dynamics, and influencing overall synaptic transmission. Shank3 is a highly penetrant monogenic cause of ASD. Despite strong genetic and behavioral evidence, the direct understanding of nanoscale-level alterations in Shank3-haploinsufficiency remain incompletely understood. On the other hand, while AMPA-R nanodomain organisation has been observed in the hippocampus, it has not been systematically examined in the striatum. This thesis investigates region-specific differences in AMPA-R nanoscale clustering between the hippocampus and striatum and characterized the consequences of Shank3 deficiency in these two brain regions, which are critically implicated in ASD behavioral phenotypes. We found that AMPA-Rs display distinct nanodomain organization in hippocampal versus striatal synapses. The differential expression of Shank family proteins in the hippocampus and striatum regulates the dependency of synapses on Shank3 for the organization and anchoring of receptors. Shank3 deficiency caused more pronounced surface alterations in AMPA-R levels in the hippocampus but had subtler effects on nanodomain structure in the striatum. Nevertheless, electrophysiological studies have revealed robust deficits in AMPA-R-mediated synaptic transmission in Shank3-KO mice. Complete Shank3 deletion also led to upregulation of the surface expression of NMDA-R in dendritic spines in both brain regions. Finally, Shank3 deletion impaired mGluR-dependent long-term depression (LTD), causing no alteration in surface AMPA-R levels upon mGluR-LTD, followed by defective LTD-induced spine loss, as revealed by super-resolution and confocal imaging. Preliminary data also revealed differential synaptic responses to inflammatory cues in Shank3 heterozygous and knockout mice. Together, with electrophysiology, super resolution microscopy and confocal imaging, this study provides the first nanoscale characterization of AMPA-R organization in the striatum and establishes a mechanistic link between Shank3 deficiency and region-specific iGluR clustering dysregulation and plasticity deficits. These findings offer new insights into well-established LTD-mechanisms using super-resolution imaging combined with the pathophysiology of ASD.
ED Sociétés, Politique, Santé Publique
“The Lebanese Sports Press: A Force for Promoting Citizenship and Affirming National Identity: A Study of the Newspapers Al Choula Al Riyadiah (1943–1954) and Al Hayat Al Riyadiah (1952–1972)”
by Cynthia NASSIF (Laboratoire Cultures, Education, Sociétés)
The defense will take place at 13h30 - l'Amphi Fabre Université de Bordeaux - 3 Ter, place de la Victoire 33 076 Bordeaux Cedex
in front of the jury composed of
- Fabien SABATIER - Professeur des universités - Université de Bordeaux - Directeur de these
- Thomas BAUER - Professeur des universités - Université de Limoges - Rapporteur
- Daphné BOLZ - Professeure des universités - Université de Rouen-Normandie - Rapporteur
- Éric DUGAS - Professeur des universités - Université de Bordeaux - Examinateur
- Karen BRETIN - Maîtresse de conférences HDR - Université Bourgogne Europe - Examinateur
This research explores the impact of the Lebanese sports press as a vector of civic formation and the construction of national identity, through the study of the weekly newspapers Al Choula Al Riyadiah (1943–1954) and Al Hayat Al Riyadiah (1952–1972), over a period extending from the end of the French Mandate to the years preceding the 1975 war. Situated within the context of a multi-confessional society, it examines these publications as spaces for the production of discourse, representations, and power relations, going beyond their purely informative function. The study is based on a qualitative analysis of previously unexplored archival material, forming a corpus selected according to chronological and thematic criteria. It highlights the structuring role of these periodicals in the formation of citizenship through sport: by relaying educational policies, supporting emerging federations, and advocating for the development of infrastructure, the press acted both as a mediator and as an active agent in the process of sports democratization. The analysis of discourses related to school sports and women's sports also reveals the gradual construction of a more inclusive sporting space, while navigating between traditional norms and the promotion of an active and civic-oriented female model. The research further emphasizes the identity dimension of these publications. In a society marked by confessional divisions, the sports press mobilized sport as a symbolic language through which a representation of the nation could be articulated. By promoting the values of national renewal, presenting sport as an antidote to sectarianism, and framing international competitions, such as the Olympic Games, the Arab Games, and the Mediterranean Games, as platforms for collective patriotism, these newspapers contributed to shaping national discourse. Events such as the boycott of the 1956 Melbourne Olympic Games and the debates surrounding the 1959 Mediterranean Games illustrate the interconnection between sport, diplomacy, and identity-related issues. However, this process of identity construction is not homogeneous. It is characterized by tensions between the ideal of national unity and the persistence of confessional dynamics, as well as between sporting autonomy and political instrumentalization. The figure of Nassif Majdalani illustrates this articulation between sports journalism, institutional engagement, and political involvement. By bringing to light previously unexplored archival sources, this research contributes to filling a historiographical gap in this general field of study. It also opens perspectives on the relationships between media, sport, and identity construction in the contemporary Lebanese context.