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An Extraction Method for the Multipath Characteristics of Simulated Tropospheric Propagation Channels
No full textInternational audienceMultipath propagation, resulting from signal reflections, diffractions, scatterings, and atmospheric ducting, poses significant challenges in wireless communication, navigation, and surveillance systems. This study focuses on evaluating the multipath characteristics in tropospheric propagation channels, particularly in air-ground systems. For long-range wave propagation in low-troposphere environments, split-step methods offer both precision and computational efficiency in modeling propagation at specific frequencies. We propose a multipath extraction approach to separate dominant propagation paths and associated multipath components by means of the postprocessing of frequency-domain simulation results. The multipath extraction relies on the Prony’s method, which allows to assess the multipath amplitude, phase, and delay from simulation results at a few frequencies. This research examines the multipath extraction method and validates the proposed models through numerical experiments across various scenarios and parameters. Simulation results are consistent with the two-ray model over flat ground. In this case, the extracted multipath reproduces the simulated channel with a root-mean-square error below –50 dB at all spatial points
On the Wasserstein geodesic principal component analysis of probability measures
No full textThis paper focuses on Geodesic Principal Component Analysis (GPCA) on a collection of probability distributions using the Otto-Wasserstein geometry. The goal is to identify geodesic curves in the space of probability measures that best capture the modes of variation of the underlying dataset. We first address the case of a collection of Gaussian distributions, and show how to lift the computations in the space of invertible linear maps. For the more general setting of absolutely continuous probability measures, we leverage a novel approach to parameterizing geodesics in Wasserstein space with neural networks. Finally, we compare to classical tangent PCA through various examples and provide illustrations on real-world datasets
Building-Aware Path Loss Modeling in ns-3
No full textInternational audienceWe propose a novel propagation model named First Order Buildings Aware Propagation Loss Model (FOBA) to address the lack of reactive interaction between signal propagation and urban building topology. The model incorporates signal loss based on three components: the direct path of the signal through buildings, diffraction, and reflection. The proposed model enhances signal path loss coherence in short-distance, object-obstructed environments. These contributions improve ns-3 representation of urban network connectivity
Enhancing the Sense of Connectedness in Participatory Systemic Workshops through Embodied Narrative
No full textThis position paper explores how embodied narrative can enhance participants’ sense of connectedness in participatory systemic workshops, particularly within the context of sustainable transportation. Drawing from a preliminary travel diary workshop, the paper outlines how bodily experiences and personal stories can be leveraged to foster mutual understanding and systemic insight
EEG-based Adaptive Visual Alerts to Mitigate UAS Operator Mental Fatigue: A Technical Proof of Concept
No full textInternational audienceUncrewed Aerial Systems (UAS) mishaps are partially attributable to mental fatigue during long endurance missions. Mental fatigue decreases cognitive flexibility resulting in a decreased performance when switching between sub-tasks. Solutions include adaptive interfaces. We propose a technical proof of concept that launches visual alerts to mitigate operator mental fatigue by estimating future performance based on brain activity (EEG). The proposed solution uses flying and detection tasks, and includes an online classification pipeline. The method is designed to work in an intra-user and inter-session manner, i.e. the solution is tuned to a user and works without calibration in the following sessions. The proof of concept was validated on three participants and compared with a previous campaign with randomly launched alerts. Very promising results were found (negative correlation between visual alerts activation and detection misses). This opens the way for the use of physiology-based adaptive interfaces to enhance user performance and safety
Semi-Automatic Building of Ontologies from Unstructured French Texts: Industrial Case Study
No full textInternational audienceAn enterprise's knowledge is often contained in a multitude of documents of different types: textual, and multimedia. Exploiting this information is generally difficult due to a lack of suitable tools. In this research work, our motivation is to assist non-expert users in creating a semantic model with minimum manual design. This paper describes a semi-automatic pipeline to build an ontology version from French texts by parsing natural language content and exploring open knowledge graphs. Specifically, with practical examples, we showcase how we integrated some existing open-source NLP solutions related to Named Entity Recognition, Relation Recognition and Named Entity Linking for building enriched ontology versions. We applied our approach to generate and manage industrial ontology versions for two real case studies: electrical grid management and requirements engineering. Finally, we conclude that having a complete and enriched knowledge graph requires larger training datasets for better NLP task 1 performances. Some steps of ontology implementation are still hard to computerize completely, notably axiom discovery which strongly relies on supervised language models
Detecting fast-ripples on both micro- and macro-electrodes in epilepsy: A wavelet-based CNN detector
No full textInternational audienceFast-ripples (FR) are short (∼10 ms) high-frequency oscillations (HFO) between 200 and 600 Hz that are helpful in epilepsy to identify the epileptogenic zone. Our aim is to propose a new method to detect FR that had to be efficient for intracerebral EEG (iEEG) recorded from both usual clinical macro-contacts (millimeter scale) and microwires (micrometer scale)
Soutenabilité environnementale absolue des trajectoires de transition du secteur aérien : une approche par l'analyse de cycle de vie prospective dans le cadre des limites planétaires
No full textIn response to escalating environmental crises, the concept of Absolute Environmental Sustainability Assessment (AESA) aims to determine whether a human activity can remain compatible with the Earth’s planetary boundaries. This thesis applies this analytical framework to commercial aviation, a sector that epitomizes the tensions between mobility, economic development, and the climate crisis.The primary objective is to assess whether the transition pathways currently envisioned for aviation are compatible with a fair and sustainable allocation of the global ecological space. To this end, the approach combines prospective Life Cycle Assessment with global energy scenarios and integrates allocation methods based on principles of environmental justice (e.g., allocations grounded in fundamental human needs). The global scenario analysis is complemented by regional breakdowns, and optimization methods are used to explore energy mixes that minimize impacts across all planetary boundaries.The results show that most current trajectories, although ambitious, lead to environmental impacts that exceed levels compatible with planetary boundaries, particularly regarding climate change, biosphere integrity, and biogeochemical flows. Scenarios relying heavily on alternative energy carriers tend to increase environmental pressures on non-climate boundaries compared to fossil kerosene, and involve high resource demands (energy, water, land, and CO2). The allocation approach influences the magnitude of the transgressions observed, and the analysis highlights that demand management is a key lever to reduce environmental impacts.By shedding light on the tensions between technological innovation, air traffic growth, and environmental sustainability, this thesis proposes a robust analytical framework to integrate planetary boundaries into the assessment of sectoral transition pathways. It contributes to current debates on the trade-offs between efficiency, sufficiency, equity, and systemic transformation in the context of long-distance mobilityFace à l’aggravation des crises environnementales, le concept de soutenabilité environnementale absolue (Absolute Environmental Sustainability Assessment, AESA) vise à déterminer si une activité humaine peut être compatible avec les limites planétaires. Cette thèse applique ce cadre d’analyse à l’aviation commerciale, un secteur emblématique des tensions entre mobilité, développement économique et crise climatique. L’objectif principal est d’évaluer si les trajectoires de transition envisagées pour l’aviation sont compatibles avec une allocation juste et durable de l’espace écologique global. Pour cela, la démarche mobilise l’analyse du cycle de vie prospective (pLCA), couplée à des scénarios énergétiques globaux, et intègre des méthodes d’allocation fondées sur la justice environnementale (par exemple sur les besoins fondamentaux humains). L’analyse des scénarios à l’échelle globale est complétée par une déclinaison régionale, et des méthodes d’optimisation sont utilisées pour explorer des combinaisons énergétiques minimisant les impacts sur l’ensemble des limites planétaires. Les résultats montrent que la majorité des trajectoires actuelles, bien qu'ambitieuses, entraînent des impacts dépassant les niveaux d'impacts compatibles avec les limites planétaires — en particulier pour le climat, la biosphère et les cycles biogéochimiques. Les scénarios impliquant un fort déploiement de vecteurs énergétiques alternatifs tendent à accroître, par rapport au kérosène fossile, les pressions environnementales sur l’ensemble des limites autres que le climat, et nécessitent une demande importante en ressources (énergie, eau, sol, CO₂). L’approche d’allocation influence l’amplitude des transgressions observées, et l’analyse met en évidence que la maîtrise de la demande constitue un levier important pour limiter les impacts environnementaux. En éclairant les tensions entre innovations technologiques, croissance du trafic aérien et soutenabilité environnementale, cette thèse propose un cadre analytique robuste pour intégrer les limites planétaires dans l’évaluation des trajectoires sectorielles de transition. Elle contribue aux débats contemporains sur les arbitrages entre efficacité, sobriété, équité et transformation systémique dans le domaine de la mobilité longue distance
Une comparaison de patrons d'architecture logicielle pour l'IHM à bas niveau
No full textThere are many patterns of software architecture for human-computer interaction. They have been designed, improved, refined and even reinvented according to a range of considerations by researchers and practitioners, as well as technological developments. However, to our knowledge, there is no synthesis or characterization of these architectures. In this article, we propose a partial synthesis of architecture patterns, with the intentions of their inventors and a formalization of their behavior. We also provide an analysis of the concerns and the components, applying the separation of concerns principles inside the Controller itself. Such a synthesis could enable future and current practitioners to better understand and compare them, in order to make informed choices during software engineering processes.Il existe de nombreux patrons d’architecture logicielle pour l’interaction humain-machine. Ils ont été conçus, améliorés, raffinés, voire réinventés en fonction d’un ensemble de considérations des chercheurs et des praticiens et des évolutions des technologies. Cependant, il n’existe pas à notre connaissance de synthèse et de caractérisation de ces patrons d’architecture. Dans cet article, nous proposons une synthèse partielle de patrons d’architecture, avec les intentions de leurs inventeurs et une formalisation de leur comportement. Nous proposons ensuite une analyse des préoccupations et des composants, en appliquant notamment le principe de la séparation des préoccupations au sein du composant Controller. La synthèse et l’analyse pourraient permettre aux futurs et actuels praticiens de mieux les comprendre et de mieux les comparer, afin de les choisir en connaissance de cause lors des process d’ingénierie logicielle
How to Better Integrate Game Theory into Technological Forecasting: Some Challenges to Tackle
No full textInternational audienceThe ability to make strategic decisions and anticipate competitors’ actions is crucial for companies to remain competitive in rapidly evolving industries. Technology roadmapping provides a comprehensive approach to assess technologies, their application, and developmental timelines. However, constructing an accurate roadmap poses challenges due to the dynamic market environment and the subjective nature of project evaluation. This paper studies the use of game theory for technology roadmapping to enhance strategic decision-making. Challenges in applying game theory, including perfect information assumptions, rational actor assumptions, utility functions modeling and successive decision-making, are examined. The necessity to bring application domain knowledge into the equation suggests an approach to bring knowledge representation techniques into game theory and see how such approaches can enhance decision-making. Metagame analysis and its branches are examined