Portail HAL U-Bordeaux
Not a member yet
125366 research outputs found
Sort by
Event triggered control and exponential stability for infinite dimensional linear systems
No full textInternational audienceThis article aims at providing a unified analysis of the exponential stabilization of some abstract infinite dimensional systems undergoing an event-triggering mechanism that samples the control input. The partial differential equation is supposed to be defined by a skew-adjoint operator and controlled and observed through bounded operators. The continuously controlled closed loop system is assumed to be exponentially stable and the goal is to prove that a well-designed event-triggering mechanism to rule the time updates of the sampled control will allow to keep such a stability property. The key of the proof relies on the existence of an adequate Lyapunov functional. Existence and regularity of the solution to the closed-loop event-triggered system are also proven, along with the avoidance of Zeno behavior
A Virome Scanning of Saffron (Crocus sativus L.) at the National Scale in Iran Using High-Throughput Sequencing Technologies
No full textInternational audienceSaffron (Crocus sativus L.) is a vegetatively propagated crop of high economic and cultural value, potentially affected by viral infections that may impact its productivity. Despite Iran's dominance in global saffron production, knowledge of its virome remains limited. In this study, we conducted the first nationwide virome survey of saffron in Iran employing a high-throughput sequencing (HTS) approach on pooled samples obtained from eleven provinces in Iran and one location in Afghanistan. Members of three virus families were detected-Potyviridae (Potyvirus), Solemoviridae (Polerovirus), and Geminiviridae (Mastrevirus)-as well as one satellite from the family Alphasatellitidae (Clecrusatellite). A novel Potyvirus, tentatively named saffron Iran virus (SaIRV) and detected in three provinces, shares less than 68% nucleotide identity with known Potyvirus species, thus meeting the ICTV criteria for designation as a new species. Genetic diversity analyses revealed substantial intrapopulation SNP variation but no clear geographical clustering. Among the two wild Crocus species sampled, only Crocus speciosus harbored turnip mosaic virus. Virome network and phylogenetic analyses confirmed widespread viral circulation likely driven by corm-mediated propagation. Our findings highlight the need for targeted certification programs and biological characterization of key viruses to mitigate potential impacts on saffron yield and qualit
Funérailles élitaires et division du corps dans la noblesse aux XVIIe et XVIIIe siècles à partir de l’exemple des comtes de Flers (Orne, Normandie)
No full textInternational audienceLa publication a pour objectif la restitution des résultats de l’opération de fouille en laboratoire des deux cercueils en plomb découverts lors de l'opération de fouille préventive de l'église paroissiale Saint-Germain à Flers (Normandie-Orne) et de son cimetière en 2014. Le P.C.R « Les cercueils en plomb des comtes de Flers (début XVIIIe s., Orne, Normandie). Pratique de l’embaumement et funérailles élitaires à l’époque moderne » développé sur quatre années (2019-2022), a permis de compléter l’étude archéologique, archéoanthropologique et documentaire. L'enjeu est donc de publier les données obtenues par la fouille et le PCR en les déployant vers une étude plus large. Les deux cercueils ont été fouillés en laboratoire en 2015 et le carditaphe déposé sur l'un des deux cercueils, autopsié en 2020 par le laboratoire d’archéoanthropologie du CRAHAM (UniCaen) sous la direction de Cécile Chapelain de Seréville-Niel. Les études ont été menées grâce à des collaborations interdisciplinaires et pluri-institutionnelles et réalisées dans le cadre du thème 2 du CRAHAM « Société, objets, territoires ». Le P.C.R a permis d’achever la totalité des études financées par le département de l’Orne, la DRAC Normandie, le CNRS et l’Inrap. Pluridisciplinaire, l’enjeu d’une telle étude est méthodologique car elle convoque l’archéologie, les archéosciences, l’archéoanthropologie et les sources documentaires. La démarche suivie a été de mettre en place des stratégies scientifiques, techniques et sécuritaires pour ce type de découvertes , appelées à devenir de plus en plus nombreuses en France, notamment dans le cadre du développement des prescriptions archéologiques préventives dans les églises paroissiales et abbatiales en contextes urbain et rural. Avec le baptême et le mariage, les funérailles font partie des rites de passage les plus importants dans le cycle de vie à l’époque moderne. Il s’agit ici d’élargir le champ historique de l’étude de cas en l’inscrivant dans la problématique générale des funérailles élitaires en Europe. La famille des comtes de Flers appartient à la noblesse seconde provinciale bien implantée dans les réseaux économiques et de cour durant toute la période moderne. L’objet de la publication est de restituer et d’interpréter les étapes des funérailles de cette famille comtale afin d’en dégager des comportements liés à une volonté de continuité familiale et lignagère. Ces comportements, qui traduisent l’idée que la famille se faisait d’elle-même et de son rang, s’inscrivent dans la conscience d’une distinction sociale plus globale. A partir de la fouille du carditaphe déposé sur l’un des deux cercueils, l’étude documentaire s’appuie ainsi sur l’analyse d’une base de données de 270 cas de partition du corps et permet de caractériser la pratique des funérailles multiples en Europe occidentale jusqu’à ses comptoirs (Asie) et colonies (Amériques)
Synthesis of piezoelectric (TMA)[FeCl4] 0D molecules and their integration into piezoelectric polymer composite
No full textNational audienc
Graft union formation involves interactions among bud signals, carbon availability, dormancy release, wound responses and non‐self‐communication in grapevine
No full textInternational audienceGrafting plants uses intrinsic wound-healing mechanisms to join together different organisms, yet the processes underpinning graft union formation remain poorly understood. To further our understanding of the molecular reprogramming triggered by grafting and wounding in a perennial plant, we characterised the transcriptome and metabolome of intact and wounded un-grafted scions and rootstocks, and homo-and hetero-grafts at 0 and 14 days after grafting/wounding in grapevine. We show that grafting triggered the coordinated activation of gene expression and the accumulation of lipids and phenolic compounds in comparison with intact tissues. We highlight an asymmetry in gene expression above and below the graft interface, which is in part not only due to carbon status, but also to intrinsic differences in gene expression between un-grafted scions and rootstocks, and their differential responses to wounding. We found that b-1,4-glucanases were differentially expressed in response to both wounding and grafting and demonstrated that exogenous b-1,4-glucanase application increased grafting success rate. Grafting, wounding, homo-graft and hetero-graft-specific transcriptome responses were characterised. The comprehensive experimental design of the dataset containing all necessary control samples allowed the identification of genes and metabolites potentially involved in wounding and grafting responses in an iconic grafted fruit crop. This is important because knowledge of genes regulating graft union formation could be leveraged for the selection of new, highly graft-compatible cultivars in the future.</div
Improving Productivity of Threaded Scientific Applications with Quo Vadis
No full textInternational audienceScientific discovery is increasingly enabled by heterogeneoushardware that includes multiple processor types, deep memoryhierarchies, and heterogeneous memories. To effectively utilize thishardware, computational scientists must compose their applicationsusing a combination of programming models, middleware, and runtimesystems. Since these systems are often designed inisolation from each other, their concurrent execution results inresource contention and interference, which limits applicationperformance and scalability. Consequently, real-world applicationsface numerous challenges on heterogeneous machines.This poster presents the thread interface of Quo Vadis, a runtimesystem that helps hybrid applications make efficient use ofheterogeneous hardware, eases programmability in the presence ofmultiple programming abstractions, and enables portability acrosssystems. Applications using OpenMP or POSIX threads can now benefitfrom Quo Vadis' high-level abstractions to map and remap full physicspackages to the machine dynamically with a handful offunctions. Furthermore, the thread interface has similar semanticsto the process interface, allowing scientists to leveragea single-semantics model for partitioning and assignment of resourcesto workers, whether they are processes or threads. With both processand thread interfaces, Quo Vadis broadens its applicability to improvethe productivity of computational scientists across programmingabstractions and heterogeneous hardware
Toward a Safe Accommodation to Faults in Control Loops via Reinforcement Learning and Reachability under Bounded Variations
No full textInternational audienceA wider deployment of learning-enabled control loops in aerospace systems requires to pay special attention to safety and fault tolerance, in particular when targeting a safe accommodation to faults and disturbances. In this paper, a training-independent offline safety verification of control loops hybridizing a baseline model-based controller and a constrainedreinforcement learning agent is considered. To this purpose, a dedicated reachability algorithm based on zonotopes is proposed to deal with bounded inputs with bounded variations. This formulation contributes to reducing conservatism while still covering a significant range of physical phenomena that are not arbitrarily fast, like surface control runaway or Oscillatory Failure Cases (OFC). The learning agent is then trained to improve given performance metrics under non-modeled environmental dynamics, including faulty scenarios. A safe accommodation scheme is so obtained and exemplified through numerical simulations using the Civilian Aircraft Landing Challenge (CALC) benchmark
Temporal heterogeneity of periphyton microbial activity and photosynthesis sensitivity to the chemical stress and its environmental drivers
No full textInternational audienc
A Switching Prescribed Performance Control Approach for Attitude Control of RLVs with Finite-Time Convergence
No full textInternational audienceThis paper presents the application of our recent published prescribed performance control theory, to the control of the attitude of a RLV during the landing approach. The proposed control solution offers the possibility to enforce the attitude error to belong to given prescribed bounds. Furthermore, it allows the attitude of the RLV, to reach its attitude’s reference in finite time. Parameters tuning of the control algorithm is also discussed. A simulation campaign conducted under a realistic flight environment (wind and atmospheric turbulence, uncertainties in the initial attitude of the vehicle), illustrates the potential of the proposed control approac