Дисертації з теми "Données de soin courant"
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Leroy, Mélanie. "Contribution des bases de données de soin courant à l’amélioration du diagnostic et du pronostic de la maladie d’Alzheimer et des dégénérescences lobaires frontotemporales." Electronic Thesis or Diss., Université de Lille (2018-2021), 2021. http://www.theses.fr/2021LILUS026.
Повний текст джерелаBiomarkers, whether cerebrospinal fluid (CSF), magnetic resonance imaging (MRI), or positional emission tomography (PET), have acquired a prominent place in the diagnostic process of a cognitive disorder. They are an integral part of the diagnostic criteria for Alzheimer's disease (AD) and its main differential diagnosis, frontotemporal dementia (FTD). In 2021, however, histological analysis, where pathological changes are observed directly on tissues, often remains the only method allowing a diagnosis of certainty.In 1992, the Lille Memory Resource and Research Center (CMRR) set up a network of memory consultations in the Nord Pas-de-Calais region. In addition to standardizing care, it has set up a database that now includes over 120,000 patients. Based on this large active file, our work consisted in studying the clinical and biochemical characteristics of AD and FTD patients on different scales (rare but perfectly characterized cases of clinicopathological correlations, monocentric cohorts of patients having undergone lumbar puncture, regional or international cohorts).Our first study focused on the correlations between the biochemical profile of cerebrospinal fluid (CSF) and post-mortem findings. We were able to show that amyloid and tau biomarkers are less sensitive to the corresponding pathologies when these are not yet fully developed in the cortex, leading to incomplete detection of patients with AD-related neuropathological changes.We subsequently focused on AD patients with pathological tau and pTau biomarkers in the CSF, pathological Aβ42/Aβ40 ratio, but normal Aβ42 levels. We showed that the cognitive, morphological, and functional profile of patients with AD and normal Aβ42 does not differ from those with pathological Aβ42.In the setting of FTD, CSF biomarkers are used to rule out a possible diagnosis of AD. Nevertheless, if this is the case, a whole spectrum of pathology remains possible as FTD is so heterogeneous. There are currently few established phenotype-pathology correlations, which, at the dawn of the development of a targeted treatment, may represent a loss of chance for these patients. We wished to constitute a multicentric cohort of patients with confirmed post-mortem FTD, in order to improve clinicopathological correlations. This preliminary work demonstrates the complexity of the FTD spectrum, with many phenotypic and histological overlaps.In addition to this study of gold standard FTD patients, we wished to consider the entire FTD active file of the Nord Pas-de-Calais memory consultation network. Although this disease is rare, the pooling of data within the network allowed us to reach a large number of patients. This work allowed us to demonstrate that FTD differs from AD, both in terms of initial characteristics, speed of progression and treatment. Despite the use of the latest clinical criteria, these pathologies remain under-diagnosed and should no longer be considered as limited to young subjects.Although each memory center, individually, is in a position to contribute to the advancement of science and to help better understand neurodegenerative diseases, it seems obvious at this time that the pooling of health data is indispensable. Within the framework of the European Human Brain Project, we have worked on the implementation of a federated data analysis tool. The Medical Informatics Platform allows complex analyses to be carried out from geographically distant databases, thus avoiding transfers and the risk of health data leaks between research centers.Data from routine care is abundant and contains a lot of information. It is up to us to make the most of it to advance our understanding of neurocognitive diseases, a challenge for the years to come
Matei, Mihaela. "Le soin courant et le standard de soin dans l'encadrement juridique de la recherche biomédicale." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTD032.
Повний текст джерелаA biomedical research protocol includes both medical and research interventions. Since its origins, the legal framework has ignored this evidence under the pretext that research and care are two distinct activities. That is why it is all the more essential to determine the nature and the scope of the duty of care and the standard of care used in the context of biomedical research. In parallel, there is a need to distinguish, from a regulatory perspective, this "standard of care" from any equivalent notions used in the context of usual care
Rodrigues, Nuno Teixeira. "Fracturation hydraulique et forces de courant : modélisation analogique et données de terrain." Rennes 1, 2008. http://www.theses.fr/2008REN1S105.
Повний текст джерелаTo understand the importance of the seepage forces applied by an overpressured fluid on the solid skeleton of a granular and permeable material we did a mechanical analysis that showed that if an overpressured fluid flows vertically through an isotropic elastic material in lithostatic conditions, it generates horizontal fractures when the fluid pressure surpasses the weight of the overburden and its tensile strength. We think that bedding parallel fibrous calcite veins (“beef”) and sand injectites formed in similar way. The study on “beef” within a source rock of hydrocarbons (Neuquén Basin, Argentina) suggested that the beef opened in pure vertical dilation when the source rock was generating hydrocarbons. Physical models showed that a variety of different shapes of sand injectites can form controlled by the seepage forces and the flexural resistance. The experimental data correlate well with seismic data from the North Sea
Hadj-Amar, Hassiba. "Identification de lignes de courant principales d'un écoulement de fluide par assimilation de données." Paris, CNAM, 2003. http://www.theses.fr/2003CNAM0476.
Повний текст джерелаWe present an original method which combines data assimilation and optimal shape design to identify principal streamlines of a fluid flow around a profile, particularly, the boundary streamline between the irrotational incompressible flow and the rotational wake. We can take observations in the area where the flow is irrotational incompressible. We consider a potential flow model. To solve the flow equations, we use an integral equations method. It allows us to solve integral equations on the boundary of a domain instead of solving an exterior problem in a domain. Using the integral equations also allows us to get a boundary mesh in the place of a surface mesh, so we avoid remeshing problem that we have with finite element methods. We minimize a quadratic gap between the observations field and the numerical values obtained by the model. The minimization parameter is the streamline we want to identify. We did the some applications with data simulated by a Navier-Stokes code. The Navier-Stokes solution is the nearest solution to a real flow
Renault, Alice. "Sur le courant circumpolaire Antarctique dans le Passage de Drake." Paris 6, 2011. http://www.theses.fr/2011PA066392.
Повний текст джерелаNieto, Adrien. "La vie privée à l'épreuve de la relation de soin." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTD024/document.
Повний текст джерелаThe existence of legal mechanisms for the protection of privacy under common law is irrefutable. Those that the patient can claim during the care relationship remain unclear. The specific nature of this relationship, and the physical and moral impairments to privacy that are consumed in it - look, touch, nudity and the exchange of private information - justify a special framework and specific protections, existing but repensable, for accompany the stakes posed by the evolution and the modification of the care relationship. The emergence of new actors in health, with their own aspirations, undoubtedly modifies the objective and consequences of this relationship. Health data, an underestimated component of privacy, in that it n° longer passes only from the patient to the healthcare professional - and vice versa - must be framed, both the economic and political stakes associated with it . The "value" of privacy must be refocused, at a time when consumption, instantaneous exchange of information and “publicy” seem to have taken precedence over it
Penz, Sébastien. "Modélisation et inversion de données électriques en courant continu : vers une prise en compte efficace de la topographie." Phd thesis, Ecole Nationale Supérieure des Mines de Paris, 2012. http://pastel.archives-ouvertes.fr/pastel-00796438.
Повний текст джерелаFruit, Gabriel. "Propagation des ondes MHD dans les couches de courant. Structure des modes et transferts énergétiques. Comparaison avec les données cluster." Toulouse 3, 2003. http://www.theses.fr/2003TOU30018.
Повний текст джерелаSince the success of the CLUSTER mission the tridimensional structure of the low frequency perturbations propagating in the key regions of the Earth magnetosphere can be studied. In order to help the interpretation of these data, this thesis propose a theoretical and self-consistent model aiming the study of the linear response of an inhomogeneous plasmasheet to an initial excitation, in the frame of the ideal MHD. Especially the calculus is lead to the final reconstruction of the spatial-temporal signals with a discussion of the amplitudes and of the energetic transfers. This last step is essential for a precise comparison with CLUSTER data. .
Vallat, Claire. "Etude du courant annulaire de la magnétosphère terrestre à l'aide des données obtenues à bord des quatre satellites du projet CLUSTER." Toulouse 3, 2004. http://www.theses.fr/2004TOU30227.
Повний текст джерелаThe ring current in the Earth's magnetosphere is a toroidal-shaped current system flowing in the near-Earth region, and results from the drift of charged particles injected during magnetospheric storms. The 4 Cluster spacecraft allow: (i) the study of the ring current ions using the CIS experiment data (which reveal very narrow spectral structures); (ii) the calculation for the first time of the current density, using FGM experiment data (curlometer technique based on 4 simultaneous points of magnetic field measurements). An analysis of the current's latitudinal profile is performed and the existence of a substantial residual current during quiet times is revealed. Finally, a comparison between ion fluxes obtained in-situ by Cluster and fluxes deduced from the inversion of magnetospheric energetic neutral atom images allows, for the first time, to validate the inversion method and proves the complementarity of the two approaches, i. E. Local measurements and neutral atom global imaging
Guihou, Karen. "Étude de la dynamique du Courant Nord au large de Toulon, à l’aide de modèle, observations in-situ et données satellites." Thesis, Toulon, 2013. http://www.theses.fr/2013TOUL0004/document.
Повний текст джерелаThe main objective of this work is to improve our knowledge of the Northern Mediterrranean Current (NC) variability and its interactions with coastal dynamics, using high-resolution modelling of the North-Western Mediterranean Sea, based on the NEMO code and nammed GLAZUR64.The configuration has been validated using all available observations for the period of study (CTD, gliders, ARGO, HF radar, ADCP, satellite altimetry and SST), in order to assess the realism of the simulations and their parameterisations. The contribution of the high-resolution for the simulation of the mesoscale dynamics, compared to 1/12° configurations used at the boundaries is shown.Finally, the use of an operationnal oceanic boundary forcing allowed us to use a combined data-model approach to study the generation and advection of an anticyclonic eddy trapped at the coast and associated to a NC meander, flowing off Toulon in April 2011 [Guihou et al., 2013]
Duchez, Aurélie. "Contrôle du courant Nord Méditerranéen dans le golfe du Lion : une approche par simulation du système d’observation." Thesis, Toulon, 2011. http://www.theses.fr/2011TOUL0005.
Повний текст джерелаOcean circulation in the Gulf of Lions is both influenced by intense atmospheric forcings and the North Mediterranean Current (NMC). A 1/16◦ configuration of the Gulf of Lions has been used to represent the complex dynamics of this area but does not allow a correct modeling of the NMC. We have used the SEEK filter data assimilation method to combine the information contained in the model and the one coming from synthetic in situ and altimetric observations (from SARAL-AltiKa altimeter). Those observations have been extracted from a realist 1/64◦ configuration of the Gulf of Lions. To assess the quality of results, statistical and physical diagnostics have been developed and show a good quality of the experiment. Thanks to a better representation of this current at the surface and at depth as well as its mesoscale activity, we have managed to improve the quantity of cross shelf exchanges. Consequently, we have managed to improve shelf water characteristics, which have thus allowed the formation of dense waters in winter, their convection and cascading over the shelf break. Rhône river plume characteristics have also been improved thanks to data assimilation. We have finally shown that assimilating those new kinds of observations in operational systems should allow the control of small scale processes closed to the coast that are not controlled with present observational systems
Moudden, Yassir. "Estimation de paramètres physiques de combustion par modélisation du signal d'ionisation et inversion paramétrique." Paris 11, 2003. http://www.theses.fr/2003PA112004.
Повний текст джерелаThe work described in this thesis investigates the possibility of constructing an indirect measurement algorithm of relevant combustion parameters based on ionization signal processing. Indeed, automobile manufacturers are in need of low cost combustion diagnoses to enhance engine control. Because of the extreme complexity of the physical phenomena in which the ionization signal originates, the traditional model-based approach appeared unrealistic and did not bring about conclusive results. We hence turned to performing a blind statistical analysis of experimental data acquired on a test engine. The analysis of high dimensional data being notoriously awkward, it is necessary to first reduce the apparent dimension of the signal data, keeping in mind the necessity of preserving the information useful in terms of our estimation problem. The usual techniques such as Principal Component Analysis, Projection Pursuit, etc. Are used to form and detect relevant variables. Further, a procedure for high dimensional data analysis derived as an extension of Exploratory Projection Pursuit, is suggested and shown to be a profitable tool. With this method, we seek interesting projections of high dimensional data by optimizing probabilistic measures of dependence such as Mutual Information, Hellinger divergence, etc. Finally, results are presented that demonstrate the quality and the stability of the low complexity in-cylinder peak pressure position estimators we derived, for a wide range of engine states
Duchez, Aurélie. "Contrôle du courant Nord Méditerranéen dans le golfe du Lion : une approche par simulation du système d'observation." Phd thesis, Université de Toulon et du Var, 2011. http://tel.archives-ouvertes.fr/tel-00627365/en/.
Повний текст джерелаZaraneh, Nabil. "Exploitation d'un réseau d'énergie électrique modulé en largeur d'impulsions pour la transmission de données par courant porteur en ligne : modélisation, simulation et expérimentation." Thesis, Nantes, 2017. http://www.theses.fr/2017NANT4092/document.
Повний текст джерелаPulse Width Modulated (PWM) networks are used in adjustable-speed drive applications. Data like, speed and rotor position, coming from sensors on the motor, are necessary for the control. Other data like, temperature and current value are important for monitoring purposes. Using Power Line Communication (PLC) techniques to transfer data from those sensors to the control has some numerous benefits. The most obvious are, simplified installation and maintenance, increase of reliability and reduction of cost. Unfortunately, PLC modems used in low-voltage sinusoidal network are not compatible with this type of application. In fact, the PLC signal suffers from power cables attenuation. In addition, the PWM voltage can generate high level noise in the bandwidth used by traditional PLC modems. Therefore, a specific PLC solution is needed in this type of applications. To find an optimized solution, the motor, the inverter as well as the cables (10, 60 and 110 meters) are modeled by a chain matrix. The transfer function calculated from the model is verified by measurements. Afterward, the PWM voltage is measured and characterized. Using the transfer function in addition to the PWM measurements, the Channel to Noise Ratio (CNR) is calculated. The CNR provides the best two center frequencies for PLC couplers. For each frequency, a couple of couplers (Tx, Rx) of 10MHz width is made. A communication simulator is made using channel model and noise (PWM) measurements. In addition, the test bench is upgraded with a QAM modem. A wide comparison is made between results (output power, bit rate and BER) obtained from the test bench and from simulations
Prodel, Martin. "Modélisation automatique et simulation de parcours de soins à partir de bases de données de santé." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEM009/document.
Повний текст джерелаDuring the last two decades, the amount of data collected in Information Systems has drastically increased. This large amount of data is highly valuable. This reality applies to health-care where the computerization is still an ongoing process. Existing methods from the fields of process mining, data mining and mathematical modeling cannot handle large-sized and variable event logs. Our goal is to develop an extensive methodology to turn health data from event logs into simulation models of clinical pathways. We first introduce a mathematical framework to discover optimal process models. Our approach shows the benefits of combining combinatorial optimization and process mining techniques. Then, we enrich the discovered model with additional data from the log. An innovative combination of a sequence alignment algorithm and of classical data mining techniques is used to analyse path choices within long-term clinical pathways. The approach is suitable for noisy and large logs. Finally, we propose an automatic procedure to convert static models of clinical pathways into dynamic simulation models. The resulting models perform sensitivity analyses to quantify the impact of determinant factors on several key performance indicators related to care processes. They are also used to evaluate what-if scenarios. The presented methodology was proven to be highly reusable on various medical fields and on any source of event logs. Using the national French database of all the hospital events from 2006 to 2015, an extensive case study on cardiovascular diseases is presented to show the efficiency of the proposed framework
Opatowski, Marion. "Résistance bactérienne aux antibiotiques, apport du système national des données de santé Hospitalisations with infections related to antimicrobial-resistant bacteria from the French nationwide hospital discharge database, 2016." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASR006.
Повний текст джерелаThe massive use of antibiotics in human and veterinary medicine has led to a significant increase of bacterial resistance to these drugs, making infections more difficult to treat. Antimicrobial resistance has become a major public health issue, which is why many action plan have been implemented at national and global scales. This thesis aims to analyze and measure the epidemiological and public health impacts of bacterial resistance to antibiotics based on the French national medico-administrative databases of health insurance (SNDS). First, an assessment of antimicrobial resistance in France was carried out. It was estimated that resistant bacteria caused 139 105 (95% CI 127 920–150 289) infections in 2016, resulting in a 12.3% (95% CI 11.3–13.2) resistance rate, and 2.52 hospitalizations for 1 000 patient-days. Then, risk factors for the acquisition resistant organisms were examined in the context of hospitalized urinary tract infections. A matched case-control analysis was conducted. This study point out the critical window of 3 months before the hospitalization of interest, the impact of broad-spectrum antibiotic consumption, urological procedures (of which prostate biopsy) and long intensive care unit stays on antibiotic resistance. Finally, the repercussion of antibiotic resistance were studied, by comparing the care pathways that follow bone and joint infections on prosthesis. A sequence analysis was conducted on a matched exposed-non exposed sample, and 6 typical care pathways were provided. Then, the use of a multinomial logistic regression allowed to compare the effect of resistance on care pathways
Barreiros, Salvado Miguel. "Optimisation des transports dans la couche active de PEMFC par une approche couplée modélisation/caractérisation : augmentation des performances des couches actives aux hautes densités de courant." Thesis, Université Grenoble Alpes, 2021. http://www.theses.fr/2021GRALI016.
Повний текст джерелаPEMFCs are among the most promising technologies for the future of the automotive industry. However, major barriers must be overcome in order to achieve a solid position in the electric vehicle market. These include the cost, where a significant fraction can be attributed to the employment of Pt in the catalyst layers.In the region of high current densities, a steep drop is commonly observed and it is usually associated with ionic and mass transport limitations in the cathode catalyst layer (CCL). Therefore, simultaneously reducing the Pt loading and improving the performance at high current density requires at first an identification of the main source(s) of performance limitations. Since the CCL is a highly heterogeneous material with features of disparate length scales, a multiscale imaging characterization setup is required in order to analyze its structure.In this work, a framework including multiscale electron microscopy (EM) characterization and multiscale modeling has been developed. Such framework allows reproducing real 3D CCL geometries using an innovative reconstruction algorithm that was designed for the purpose. Moreover, a physical model is implemented in these 3D geometries, and subsequently, numerical simulations at the local and CCL scales are performed. The multiscale EM setup includes FIB-SEM from which the carbon phase distribution is determined, HAADF-STEM to determine the representative Pt particle size distribution, and finally, HRTEM from which an average thickness for the Nafion thin film is measured. These images go through a post-treatment procedure which includes segmentation and alignment for the tomographic images. From these, geometries are then reproduced. Moreover, a physical model including multispecies transport on the Nafion and pore phases, ionic transport on the Nafion phase and a Butler-Volmer law at the Pt interface to describe the ORR kinetics, is implemented. The CCL 3D model is then coupled with a 2D MEA-scale model, from which local conditions are extracted and subsequently used as input in the local model. An analysis on the 3D geometries is then performed at both local and CCL scales. Regarding the former, it is found that structures with smaller Pt particles always present a better performance due to an increase in the amount of surface available for the electrochemical reaction to proceed. Though, the presence of Pt particles in large Nafion agglomerations as well as Pt interparticle competition effects can play a major detrimental role on performance (differences in local performance up to 26%). In the CCL scale analysis, the effects of the Pt particle size, the Nafion layer thickness and carbon aggreggate size are analyzed. In accordance to what is observed at the local scale, structures with smaller particles also display a better performance. Regarding the Nafion layer thickness, a balance between an enhancement in ionic transport and an increased resistance to oxygen transport upon thickening of the Nafion film has been highlighted. Results show that increasing the Nafion layer thickness from 8 to 10 nm is only benefitial for performance when the porosity is above 30%. Furthermore, these support the fact that understanding the swelling behavior of the Nafion thin film is crucial for a more accurate determination of the CCL's response. In its turn, enlarging the carbon aggregates can be detrimental for performance since some pores may vanish and regions with Pt particles located on large Nafion agglomerations may become starved from oxygen. Finally, the impact of the structure arrangement has been analyzed and gains in performance upon minimizing the tortuosities of both Nafion and pore phases to unity have been quantified. An improvement in performance of 25% was found, mainly as a result of the favoured ionic transport
Gizzarelli, Francesco. "Mesure du rapport des sections efficaces d'interaction des neutrinos sur les noyaux d'oxygène et de carbone, à partir des données du détecteur proche ND280 de l'expérience T2K." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS259.
Повний текст джерелаThe Standard Model of particle physics describes the interactions of subatomic particles through the strong, weak and electromagneticinteractions. However, it is known that this theory is not a complete description of the nature. Indeed the observation that neutrinos can change their flavor alongtheir propagation path (neutrino oscillation) proves that they actually have a mass. The work of this thesis has been performed in the T2K oscillation experiment: a long baseline experiment located in Japan. % detailed in Chapter ref{sec_t2k_res}.Using the data collected so far, T2K has been able to observe for the first time the $nu_{mu} rightarrow nu_e$ appearance and to give first results on the Charge-Paritysimmetry in neutrino oscillation. It provides also precise measurements of the oscillation parameters θ₁₃ , θ₂ ₃, Δm²₂ ₃.The precise measurement of oscillation parameters requires a good understanding of the detector and of the neutrino interaction model. This thesis is thus focused on boththese aspects: reduce the detector uncertainties and improve our knowledge of neutrino interactions with matter.The CEA Saclay group where I am involved, is in charge of the maintenance and operation of the Time Projection Chambers (TPCs) of the T2K near detector (ND280)which are used to identify and measure the kinematics of the charged particles produced in neutrino interactions.Part of my work was focused on the study of the TPC and in particular on the alignment of the MicroMegas modules instrumenting their readout planes.Indeed, misalignments between modules may cause a bias on the momentum measurement of the particles crossing the TPC.Neutrinos are studied through the observation of the final state of their interactions with matter. Therefore, the interactionmodels need to be extremely well understood to infer the neutrino properties correctly.Indeed current and next future oscillation experiments are approaching the phase of precise measurements of the mixing parameters becominglimited by our knowledge of neutrino interactions.The charged current quasi-elastic (CCQE) interaction is the most relevant process at T2K.This manuscript describes the measurement of CCQE cross-section ratio between oxygen and carbon nuclei. It can contribute to reduce the uncertainties on the oscillation analysis arisingfrom the different target between the near and far detector
Thual, Sulian. "Modèles réduits pour l'étude des mécanismes et de la modulation de l'oscillation australe El Niño." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1821/.
Повний текст джерелаThe El Niño Southern Oscillation (ENSO) is the most intense climatic fluctuation on Earth after the seasonal cycle. The observation, understanding and forecast of this fluctuation with worldwide impacts are major scientific issues. This thesis (entitled "Simple Models for Understanding the Mechanisms and Modulation of ENSO") documents various aspects of ENSO such as its mechanisms, its modulation and its forecast. Those various aspects are tackled by developing a hierarchy of models of the equatorial Pacific, of increasing complexity, ranging from conceptual models to a data assimilation method in an intermediate complexity model. We study at first mechanisms of ENSO formation. We develop an alternative derivation of the recharge/discharge conceptual model where ENSO arises from a basin-wide adjustment of the equatorial thermocline. We also implement an original diagnostic in a model of equatorial coupled instabilities, which evidences a new mechanism of ENSO formation where reflections at the ocean boundaries are secondary. The background ocean stratification contributes to the decadal modulation of ENSO characteristics. This relation is adressed in a new reduced model that takes into account the gravest baroclinic modes of a continusouly stratified ocean. The space of model solutions is explored, indicating a control on ENSO stability by characteristics of the equatorial thermocline. The sensitivity to stratification over the recent decades is put in perspective with the sensitivity to thermodynamic and atmospheric feedbacks. We stress in particular certain limitations of usual methods of estimation of the thermocline feedback in the central Pacific. Finally, we implement an Ensemble Kalman Filter method in an already existing intermediate model of the equatorial Pacific, in order to assimilate sea level observations and to initialize retrospective forecasts. We show that the major model constraint is on the basin modes that are associated to the recharge/discharge process of the equatorial Pacific. Our work provides a formalism to diagnose the modulation of ENSO characteristics in observations, climate projections and forecasts. Results support the need to extent the understanding of ENSO mechanisms, in order to account for the diversity of observed regimes and to improve forecasts
Danilo, Céline. "Évaluation des courants de surface océanique au moyen d’un radar à ouverture synthétique." Brest, 2009. http://www.theses.fr/2009BRES2023.
Повний текст джерелаThe aim of this thesis is to extract the radar line-of-sight component of sea surface current from the Doppler shift of a signal received by a synthetic aperture radar on board of ENVISAT. The primary goals of this work are the separation of waves and surface current components to this Doppler shift and, furthermore, the expansion of this analysis to multiple angles of incidence, thereby making it possible to map sea surface currents. This study is limited to vertical polarization and to the radar frequency hand C. Extraction of current signature is based on the assumption that the Doppler shift is caused solely by surface gravity waves and by surface current. Moreover, we initially assume that the current is uniform within the surface of Doppler shift estimation. Under these assumptions, the current component can be deduced from the Doppler shift by substracting the wave component. The latter have relatively short wavelengths, which is typical of wind-sea. Practical use of 10 m wind information for the estimation of waves component is evaluated. A method for extracting surface current information is developed and tested, initially for a constant incidence angle of 23°, on small-sized and isolated ocean images from all over the oceans. A comparison of the monthly average speeds, obtained by on-site current measurements, indicates an RMS error of 0. 35 m/s. As a further step, the same methodology is applied for larger acquisitions (400 km by 400 km minimum) for which the incidence angle ranges from 16 to 42°, This new configuration requires a preliminary analysis of the effect of incidence angle variation on the Doppler shift. We show that an increase of the angle of incidence results in the increase of the relative component of surface current to the Doppler shift, and that the latter also varies according to the direction of wind with respect to the direction of the radar. The estimated surface current component shows a good quantitative correspondence with the same component measured by on-site sensors. This result is encouraging in view of the development of a more systematic technique. Finally, the last part of this work is devoted to a more complex case, namely that of coastal current: here, the hypothesis of a uniform surface current within the estimation surface cannot be maintained anymore due to the great variability of these currents. In this case, we proceed by analyzing maps of Doppler shift of a 1 km resolution. Despite the complexity of this situation, once again, the comparison between Doppler shift-derived velocities and data from tidal current maps indicates a strong potential of SAR images to return high resolution information on surface currents
Marmain, Julien. "Circulation côtière en Méditerranée Nord Occidentale : courantométrie par radar HF et couplage avec un modèle numérique." Phd thesis, Toulon, 2013. http://tel.archives-ouvertes.fr/tel-00994937.
Повний текст джерелаFlorenchie, Pierre. "La circulation de l'océan Atlantique Sud : expériences de simulation avec un modèle quasi-géostrophique et l'assimilation des données altimétriques des satellites TOPEX/POSEIDON et ERS1." Grenoble INPG, 1996. http://www.theses.fr/1996INPG0198.
Повний текст джерелаLuong, Bruno. "Techniques de contrôle optimal pour un modèle quasi-géostrophique de circulation océanique : application à l'assimilation variationnelle des données altimétriques satellitaires." Phd thesis, Université Joseph Fourier (Grenoble), 1995. http://tel.archives-ouvertes.fr/tel-00005055.
Повний текст джерелаDanilo, Céline. "Évaluation des courants de surface océanique au moyen d'un radar à ouverture synthétique." Phd thesis, Université de Bretagne occidentale - Brest, 2009. http://tel.archives-ouvertes.fr/tel-00560597.
Повний текст джерелаCarret, Alice. "Étude de la variabilité spatio-temporelle de la circulation en Méditerranée nord-occidentale : apport de l'altimétrie spatiale." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30288.
Повний текст джерелаSatellite altimetry, which is a powerful tool for studying ocean dynamics offshore, has led to dramatic advances in our knowledge of the ocean. The challenge is now to combine this tool to coastal observing techniques and to investigate the potential applications. In this framework, the North-Western Mediterranean Sea has been chosen for its wide range of mesoscale dynamics and for the avaliablity of numerous instruments deployed in this region. Technological innovations (Ka band, Synthetic Aperture Radar) and advances in data processing have enhanced accuracy and improved spatial resolution and coverage. Using several in situ datasets (HF radars, gliders, hull-mounted ADCP), cross- comparisons were carried out to study the observability of the Northern Current and its variability from each type of instrument. These allowed analysing the contribution of a multi-platform observing system in monitoring coastal processes. They also highlighted the complementarity of each instrument. To optimize the use of altimetry in coastal studies, a HF regional model (Symphonie) is used to quantify what component of the current can or can't be observed and to analyze the origin of the differences that were observed between each type of in situ current observations and altimetry data. After model validation, it was used to quantify the sea surface height signature of the Northern Current and of the convection and to evaluate to what extent these processes are captured by satellite altimetry. The impacts of the spatial and temporal resolutions, transects orientation, the location and the physical content were also investigated. Besides linking the different types of data and helping us to interpret the results obtained, the Symphonie model enabled to study the circulation and its seasonal and interannual variability at the regional scale. Some hypothesis about the origin of the observed spatio- temporal variations were investigated. With the forthcoming launch of the SWOT mission in 2021, this manuscript suggests perspectives about the use of integrated observing systems, altimetry data exploitation in coastal areas and validation strategies at the regional scale
Lu, Liping. "Performances and quality of service of PLC networks for MV and LV distribution systems." Thesis, Vandoeuvre-les-Nancy, INPL, 2006. http://www.theses.fr/2006INPL080N/document.
Повний текст джерелаDans cette thèse, nous nous intéressons à la problématique liée à la communication numérique sur courant porteur dans l’objectif de fournir une infrastructure de communication qui permet la surveillance et le contrôle de la distribution et de la consommation de l’énergie. Ce travail a été effectué dans le cadre du projet européen REMPLI (Real-time Energy Management via Power Line and Internet) et a produit la spécification REMPLI PLC (Power Line Communication). Pour fournir une meilleure performance de la communication et effectuer le transfert de données en temps réel, en utilisant les réseaux électriques de moyenne tension et de basse tension, les problèmes principaux qui sont le routage dynamique de paquets de données, la gestion de la qualité de service et la notification des événement en temps réel, ont été traités. Nous avons développé un protocole de routage efficace pour s’adapter au changement dynamique de topologie du réseau électrique. Les performances de REMPLI PLC sont évaluées en utilisant des approches de simulation couplée avec des approches analytiques. Il est prouvé que la majorité des besoins applicatifs peuvent être satisfaite par REMPLI PLC. Nous avons proposé et implanté un nouvel “ordonnançeur de traffic” fournissant différents niveaux de qualité de service pour les applications. Des variantes de protocole ALOHA ont été proposées et évaluées afin de vérifier que les propriétés temps réel requises sur les notifications d’événements sont respectées
Dodet, Guillaume. "Morphodynamic modelling of a wave-dominated tidal inlet : the Albufeira lagoon." Thesis, La Rochelle, 2013. http://www.theses.fr/2013LAROS413/document.
Повний текст джерелаWave-dominated tidal inlets are very dynamic coastal systems, whose morphology is continuously shaped by the combined action of the waves and the tides. The rapid morphological changes they experience impact directly their ecological and socio-economic environments. In order to implement adequate regulations for the sustainable management of tidal inlets, systematic environmental studies are necessary. The main objective of this PhD research work is to gain a better understanding of the physical processes that control the morphological evolutions of an ephemeral tidal inlet in Portugal - the Albufeira Lagoon inlet - based on the analysis of hydrodynamic and topographic data and on the results of a newly developed morphodynamic modelling system. The processes that impact the dynamics of the inlet at short time-scales, particularly those related to wave-current interactions, are investigated through the application of the modelling system to the inlet. The seasonal modulations of the wave climate and mean sea level strongly affect the sediment dynamics of the inlet and contribute to the natural closure of the inlet during the winter period. Long-term processes are also investigated based on a 65-year hindcast of mean wave parameters at regional and local scales. The large inter-annual variability of the wave climate and the associated longshore sediment transport – both correlated to the North-Atlantic Oscillation – are proposed to explain the differences in the morphological behaviour of the inlet-lagoon system at pluri-annual time-scales
Joo, Arakawa Rocío. "A behavioral ecology of fishermen : hidden stories from trajectory data in the Northern Humboldt Current System." Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20224/document.
Повний текст джерелаThis work proposes an original contribution to the understanding of fishermen spatial behavior, based on the behavioral ecology and movement ecology paradigms. Through the analysis of Vessel Monitoring System (VMS) data, we characterized the spatial behavior of Peruvian anchovy fishermen at different scales: (1) the behavioral modes within fishing trips (i.e., searching, fishing and cruising); (2) the behavioral patterns among fishing trips; (3) the behavioral patterns by fishing season conditioned by ecosystem scenarios; and (4) the computation of maps of anchovy presence proxy from the spatial patterns of behavioral mode positions. At the first scale considered, we compared several Markovian (hidden Markov and semi-Markov models) and discriminative models (random forests, support vector machines and artificial neural networks) for inferring the behavioral modes associated with VMS tracks. The models were trained under a supervised setting and validated using tracks for which behavioral modes were known (from on-board observers records). Hidden semi-Markov models performed better, and were retained for inferring the behavioral modes on the entire VMS dataset. At the second scale considered, each fishing trip was characterized by several features, including the time spent within each behavioral mode. Using a clustering analysis, fishing trip patterns were classified into groups associated to management zones, fleet segments and skippers' personalities. At the third scale considered, we analyzed how ecological conditions shaped fishermen behavior. By means of co-inertia analyses, we found significant associations between fishermen, anchovy and environmental spatial dynamics, and fishermen behavioral responses were characterized according to contrasted environmental scenarios. At the fourth scale considered, we investigated whether the spatial behavior of fishermen reflected to some extent the spatial distribution of anchovy. Finally, this work provides a wider view of fishermen behavior: fishermen are not only economic agents, but they are also foragers, constrained by ecosystem variability. To conclude, we discuss how these findings may be of importance for fisheries management, collective behavior analyses and end-to-end models
Guihou, Karen. "Étude de la dynamique du Courant Nord au large de Toulon, à l'aide de modèle, observations in-situ et données satellites." Phd thesis, 2013. http://tel.archives-ouvertes.fr/tel-00917904.
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