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Optimal experimental design for full waveform inversion using a wavenumber sampling criterion-Part 2: 3-D extension and practical application
No full textInternational audienceIn a companion paper, we have proposed an optimal experimental design (OED) strategy for seismic imaging. Using the theory of diffraction tomography, for a specified target, given an acquisition geometry and a prior information on the subsurface velocity, we characterize the wavenumber space of the image that would result at the image point from such an acquisition. Our strategy relies on optimizing the sources and receivers positions so as to guarantee a regular sampling of the wavenumber space within the pre-computed envelope. The regularity of a given sampling is assessed through the use of Voronoi tessellations, associated with the wavenumber points cloud. Computing a centroidal Voronoi tessellation, which can be formulated as an optimization problem, guarantees a regular tessellation, which in turns provides a regularly spaced wavenumber points cloud. We have introduced this method in a 2-D context, in relatively simple settings. In this second paper, we present the extension of this method to a more realistic framework and investigate its application to synthetic case studies. This extension consists in considering now a fully 3-D geometry, as well as specific deployment constraints with polygonal shaped deployment zones and non-accessible (exclusion) zones for the sources and receivers. Such type of constraints are commonly met in survey design and it is important to be able to take them into account in an OED algorithm. We investigate on simple velocity models the feasibility and limitations of our method for target-oriented seismic imaging using full waveform inversion
Physics briefing book: Input for the 2026 update of the European Strategy for Particle Physics
No full textInternational audienceThe European Strategy for Particle Physics (ESPP) reflects the vision and presents concrete plans of the European particle physics community for advancing human knowledge in fundamental physics. The ESPP is updated every five-to-six years through a community-driven process. It commences with the submission of specific proposals and other input from the community at large, outlining projects envisioned for the near-, mid-, and long-term future. All submitted contributions are evaluated by the Physics Preparatory Group (PPG), and a preliminary analysis is presented at a Symposium meant to foster a broad community discussion on the scientific value and feasibility of the various ideas proposed. The outcomes of the analysis and the deliberations at the Symposium are synthesized in the current Briefing Book, which provides an important input in the deliberations of the Strategy recommendations by the European Strategy Group (ESG)
Évolution des usages de trois glacières naturelles des montagnes françaises à travers les siècles
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Flexibilité de la régulation émotionnelle : Qu’est-ce que c’est et pourquoi l’étudier en lien avec la paranoïa ?
No full textInternational audienceLa flexibilité de la régulation émotionnelle (RE) joue un rôle clé dans l’adaptation aux situations changeantes et pourrait influencer la survenue et le maintien des pensées paranoïaques. Des études suggèrent que les individus présentant une propension à la paranoïa ont des difficultés à adapter leurs stratégies de RE au contexte, utilisant de manière rigide des stratégies inadaptées ou inefficaces. Toutefois, la flexibilité en matière de RE en lien avec la paranoïa en vie quotidienne reste peu explorée. Cette étude utilise une méthode du type journal quotidien sur 14 jours afin d'examiner le lien entre les trois composantes de la flexibilité de la RE (sensibilité au contexte, répertoire de stratégies, et feedback) et la paranoïa dans la population générale. Les participant.es seront recruté.es via la plateforme Prolific et répondront quotidiennement à des questionnaires évaluant leur état émotionnel, leur perception du contexte (interne et externe), leurs stratégies de RE et leur efficacité, ainsi que leur niveau de paranoïa. Les données seront analysées via des modèles multiniveaux sous R pour tenir compte de la structure hiérarchique des mesures répétées. Nous anticipons qu’une sensibilité contextuelle limitée, un recours restreint aux stratégies de RE, une faible variabilité dans leur mise en œuvre ainsi qu’une persistance dans l’utilisation de stratégies inefficaces contribueront à la paranoïa. Cette étude montre l’importance d’un design écologique pour étudier comment la variabilité des stratégies de RE et des facteurs contextuels influence la flexibilité de la RE, apportant des informations cruciales sur leur contribution à la paranoïa et permettant d’orienter plus finement les interventions ciblant la régulation émotionnelle en vue de réduire les pensées paranoïaques
Chronicles of an announced landscape disaster and lessons for the future: spatial modelling of the plane tree Canker stain
No full textInternational audiencePlane tree Canker stain which is caused by the fungus Ceratocystis platani is the most harmful disease of plane trees in the world. Despite a large corpus of scientific literature, there are no case studies of the biogeographical distribution and historical expansion of the tree and this harmful associated organism at the landscape scale. The connection between landscape ecology tools and concepts and the changes in composition or loss of major elements like remarkable trees of landscape heritage is neither established. Based on previous research into the detection and dispersal of Dutch Elm Disease in Western Europe and after the large felling of thousands of plane trees alongside the UNESCO World Heritage site “Canal du Midi” since 2006, representing a true landscape disruption which leads to local conflicts, the aim of this study was to evaluate and assess the effectiveness of the spatial dispersal of plane tree Canker stain in the city of Toulouse and its connections with the two waterways using open-access georeferenced data on dendrometrical characterics. It indicates how spatial modelling of ecological anti-corridors can help to slow down the spread of the disease and provide for gradual replacement of trees to restrain its spread along the “Canal Latéral à la Garonne”. Our contribution is also questioning how the landscape structures and connectivity can facilitate or impede the disease spread among host patches
Experimentation of an autonomous solar cold room with thermal emulation of virtual food storage
No full textInternational audienceThe development of autonomous solar cold rooms faces challenges in regions with abundant solar resources but limited electrical grid infrastructure. Key issues include reliable energy storage, efficient refrigeration, and system portability for agricultural goods storage. Previous studies often neglected the dynamic temperature evolution of stored goods, crucial for food preservation. CEA and AIRWELL collaborated to design and test a Cold Room Solar Autonomous (CFSA) system prototype. The CFSA system includes a lead-acid battery, a 4 kWth refrigeration unit, a configurable PV field with 20x 500 Wpeak PV modules, an 8000 VA DC/AC inverter, DC MPPT chargers, and a cold room connected to a backup electrical network. CEA developed an emulation method of the actual internal thermal load for such system test, under dynamic conditions to maintain food temperatures, using heating resistors controlled by a dynamic thermal simulation. Testing on the CEA platform from August to November 2024 included various sensors and controllers while the Scilab models and simulation of the thermal mass provided performance insights. The battery maintained continuous refrigeration with 32 hours of autonomy without solar input during virtual matter’s temperature drop phase. The PV field ensured operational autonomy with 3kWh/kWc/day under reduced sunshine, requiring a backup source approximately every 3 days under low sunshine and temperature difference conditions. The experimental methodology developed in this work opens further development perspective of the CFSA hybrid micro plant to support the local grid balance by adjusting its energy storage and consumption in response to grid operators' signals. The estimated flexibility is about 1%/t.K referring to the CFSA system nominal power consumption, food mass stored and ind/out temperature difference
Les mécaniques d’altérité : la suite(case) de l’in/humain
No full textInternational audienceComment une mécanique d’altérité – avec la métaphore de la valise – conduit-elle à envisager le monstrueux non plus comme une menace ou un Autre extérieur mais comme une double peau, animale et nécessaire à notre humanité ? Nous proposons de l’envisager au travers de deux de nos dispositifs numériques expérimentaux : ] PPP [ (2023) et R/FRAME (2019
LCA methodology for zero-emission vehicle (ZEV): Selection of impact categories and normalisation factors by consensus building
No full textInternational audienceTransport is responsible for 30% of the EU’s greenhouse gas emissions, underlining the urgency to develop andfoster sustainable mobility services in Europe like zero tailpipe emissions vehicles (ZEVs). Therefore, robust LifeCycle Sustainability Assessment (LCSA) methodologies are needed to inform decision makers, and evaluate andmonitor the sustainability of ZEVs. TranSensusLCA (TSLCA) aims at developing a European commonly acceptedLCSA approach for ZEVs. The project aspires to improve representativeness and comparability between LCAs.Gathering relevant stakeholders from industry and research, a realistic and scientifically sound LCA approach isbeing conceived and harmonized. By consensus, TSLCA will help decision makers to provide sustainable productsand optimize mobility solutions.One of the key aspect of LCSA is Life Cycle Impact Assessment (LCIA) and normalisation. However, use of differentimpact categories (IC), indicators and normalisation factors (NFs) hinders the comparison of diverse LCA studies.To address this challenge, TSLCA proposes to standardise key elements of LCIA and ensure comparability,including IC, indicators, assessment methods, and normalisation.Following a TSLCA consensus building process, a comprehensive selection of environmental impact categorieswas made, encompassing relevant issues within the product's supply chain. To evaluate the relevance of each typeof impact for ZEVs, a list of existing LCA IC were analysed and scored based on five criteria: 1) robustness, 2)relation to planetary boundaries (PBs), 3) importance for ZEVs, 4) data availability, and 5) ease of use. Seven ICor indicators have been selected as mandatory after three voting rounds.Though normalisation is seldom mentioned in guidelines and considered a subjective step, TSLCA acknowledgesits usefulness and recommends it as optional. After a review and evaluation of existing NFs, the NFs in relation toPBs were recommended. Although not completely mature yet, it was deemed that an absolute approach is themost relevant in TSLC