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Performances des protocoles QKD, BB84 et SARG04 pour les communications quantiques sous-marines
No full textInternational audienceDans le contexte des communications sous-marines sécurisées et plus précisément des transmissions de clés de cryptage par un processus quantique (Underwater Quantum Key Distribution -UQKD), cette étude cherche à mettre en évidence l'influence du canal de propagation sur l'efficacité de la transmission. Nous comparons ainsi deux protocoles de QKD à variables discrètes : BB84 et SARG04, en fonction de la distance de propagation, des caractéristiques d'eau de mer (claire, côtière et trouble) et des conditions atmosphériques. Le critère principal de comparaison consiste en une analyse quantitative du taux d'erreur de bit quantique (Quantum Bit Error Rate -QBER). Nous nous basons pour cela sur une expression analytique déjà établie et connue de la littérature et proposons une simulation numérique en fonction des paramètres du modèle de mer.</div
Inner and outer approximation of the image of a set by a nonlinear function
No full textInternational audienceThis paper proposes an original method to compute an inner and an outer approximation of the image f (X) of a subset X of R^n (e.g., X is the unit ball) by a smooth nonlinear function f : R^n → R^n . A boundary approach is proposed. More precisely, the boundary ∂f (X) will be covered by parallelepipeds in order to get an accurate enclosure of f (X)
Contribution à l’étude de la réponse de matériaux hétérogènes soumis à des sollicitations environnementales et mécaniques
No full textThis document presents a summary of approximately fifteen years of applied research into the response of heterogeneous materials to environmental and mechanical loading. One area of focus within this research is the response of metallic materials to wide temperature variations, an oxidizing environment, and mechanical loading. Materials under investigation include zirconium alloys, chromium-coated zirconium alloys, and a martensitic steel. The following issues are addressed: high temperature corrosion, mechanical behavior, failure, and the influence of microstructural changes, and heterogeneities induced by temperature variations and corrosion (phase changes and oxygen and hydrogen absorption, for example). Another area of focus in the research is the response of heterogeneous polymer-based materials to cyclic mechanical loading in environments (temperature and humidity in particular) that may vary in certain cases. The work presented examines the thermomechanical behavior and fatigue life of a range of materials, including short fiber-reinforced thermoplastic matrix composites, long fiber-reinforced thermoset matrix composites, and elastomer foams. The methodology employed integrates multiscale experimental characterization, modeling, and numerical simulation.Ce document fait la synthèse d’une quinzaine d’années de recherche, à vocation appliquée, sur la réponse de matériaux hétérogènes soumis à des sollicitations environnementales et mécaniques. Une partie de ces activités de recherche porte sur la réponse de matériaux métalliques soumis à des variations importantes de température, à un environnement oxydant et à des sollicitations mécaniques. Les matériaux étudiés comprennent des alliages de zirconium, des alliages de zirconium revêtus de chrome et un acier martensitique. Les problématiques abordées incluent la corrosion à haute température, le comportement mécanique, la rupture, et l’influence des évolutions microstructurales et des hétérogénéités induites par les variations de température et la corrosion (changements de phases et absorption d’oxygène et d’hydrogène par exemple). Une autre partie des activités de recherche présentées porte sur la réponse de matériaux hétérogènes à base de polymères soumis à des chargements mécaniques cycliques, dans des environnements (température et humidité notamment) susceptibles de varier dans certains cas. Les travaux exposés portent sur le comportement thermomécanique et la tenue en fatigue de différents matériaux incluant des composites à matrice thermoplastique renforcée de fibres courtes, des composites à matrice thermodurcissable renforcée de fibres longues et des mousses élastomères. La démarche mise en œuvre associe caractérisation expérimentale, modélisation et simulationnumérique
Encadrer la probabilité de succès d'une mission de lutte contre les mines navales conduites par des AUVs.
No full textInternational audienceThe success of mine-clearance missions conducted by Autonomous Underwater Vehicles (AUVs) mainly depends on two inter-related factors: the AUV behavior and the validation of a mission assumption. AUVs are typically modeled as stochastic dynamical systems and controlled using probabilistic techniques, such as Kalman filtering, to handle environmental uncertainties and inherent behavioral randomness. Assumption validation, on the other hand, often relies on set-based conditions, such as detecting an object on the seabed using an onboard exteroceptor, resulting in a three-valued logic outcome: success, failure, or uncertain. Thus, estimating mission success involves computing the probability of an event whose realization can be uncertain and influenced by a stochastic system (i.e. the AUV). In this paper, we extend traditional binary outcome models to a three-valued logic framework and introduce an empirical estimator based on the Monte Carlo method to bound the success probability within an interval. As with the standard binary outcome Monte Carlo estimator, the accuracy of this estimated interval improves with the number of trials, following the law of large numbers
Empowering sustainability: can women engineers play a key role in achieving a sustainable future?
No full textInternational audienceEngineers are considered key professionals and the main driver for achieving the United Nations 17 Sustainable Development Goals (SDGs). Despite this, engineering has long been thought to be man's job, leading to persistent gender disparity in the profession. This study aims to gain a nuanced understanding of gender differences, if any, in engineers' awareness and attitudes towards sustainable development (SD). It aims to assess students' perceptions regarding the importance of sustainability and obstacles to SD. It also examines their views on sustainable practices, design projects, university encouragement, campus initiatives, and the role of engineers in advancing sustainability. A structured online survey, consisting of closed-ended questions, was designed to evaluate students' knowledge and perceptions of sustainability and to identify meaningful differences between male and female students in the field of engineering using the Faculty of Engineering, at the University of Balamand, in Lebanon. The results show that female engineering students scored higher than their male peers with two aspects being of statistical significance related to SD importance. Moreover, female students demonstrated a stronger awareness of SD related challenges and placed greater emphasis on the social pillar of sustainability. These findings highlight the critical importance of encouraging more women to pursue engineering studies and remain active in the profession. Empowering women in engineering can contribute meaningfully to sustain the engineering profession by diversifying it, and by shaping a more sustainable and equitable world.</div
The Role of Maritime Training in Algeria in Achieving the Sustainable Development Goals
No full textInternational audienceAlgeria has officially adopted the United Nations' 2030 Agenda and is committed to achieving the 17 Sustainable Development Goals (SDGs), including SDG 14, "Life Below Water," which concerns the maritime sector, a strategic component of the national economy. In this regard, several measures have been implemented, notably the training of maritime professionals to reduce accidents affecting the marine environment and contribute to addressing maritime challenges. This paper aims to examine the regulatory frameworks and policy orientations governing this field and to evaluate the nature and content of maritime training programs in order to determine their role in advancing the SDGs. Data were collected through a qualitative approach combining document analysis and interviews.The findings reveal that Algeria has established strategic orientations for the maritime sector to address environmental challenges and mitigate the stagnation observed in SDG 14 progress. A legislative and institutional framework has been developed, and maritime training and research have been integrated into the strategies of higher education institutions. Regarding training programs, ENSM designs and offers degree, qualification, and certification programs to meet the sector's needs. However, the study highlights a lack of international partnerships and the limited presence of social sciences and humanities courses in maritime training curricula. As for sustainable development concepts, the results show that they are integrated into certain modules of training programs, in addition to other seminars and study days organized to raise awareness of these issues.</div
Projection onto the core: An optimal reallocation to correct market failure
No full textThis paper provides formulae and algorithms to compute the projection onto the core of a preimputation outside it. The core of a game is described using an exponential number of linear constraints, and we cannot know beforehand which are redundant or defining the polytope. We apply these new results to market games, a class of games in which every game has a nonempty core. Given an initial state of the game represented by a preimputation, it is not guaranteed that the state of the game evolves toward the core following the dynamics induced by the domination relations. Our results identify and compute the most efficient side payment that acts on a given state of the game and yields its closest core allocation. Using this side payment, we propose a way to evaluate the failure of a market to reach a state of the economy belonging to the core, and we propose a new solution concept consisting of preimputations that minimizes this failure
Tracing-Based I/O Diagnosis for Performance Optimization of Software-Defined Storage Systems
No full textInternational audienc
Security of Dynamically Reconfigurable RISC-V Systems: I/O Attack Focus
No full textInternational audienceDynamic Partial Reconfiguration (DPR) enhances flexibility in modern hardware but introduces security risks. This work demonstrates how a Malicious Hardware Accelerator (MHA) can exploit Direct Memory Access (DMA) to bypass Input Output Memory Management Unit (IOMMU) protections through device ID manipulation, enabling unauthorized memory access. This vulnerability exposes a fundamental security gap in the management of dynamically reconfigurable systems. By highlighting this issue and proposing mitigation strategies, we provide a conceptual framework to guide the development of security mechanisms for dynamically adaptable architectures
