Tesi sul tema "Algorithme de restitution"
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Megharbi, Djamel. "Restitution de paramètres thermodynamiques par reconnaissance d'environnements dans les graphes de composés". Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL091N.
Deprez, Romain. "Optimisation perceptive de la restitution sonore multicanale par une analyse spatio-temporelle des premières réflexions". Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4746/document.
The goal of this Ph. D. thesis is to optimize the perceived quality of multichannel sound reproduction systems, in the context of a domestic listening room. The presented research work have been pursued in two different directions.The first deals with room effet, and more particularly with physical and perceptual aspects of first reflections within a room. These reflections are specifically described, and a psychoacoustical experiment have been carried out in order to extend the available data on their perceptibility, i.e. their potency in altering the perception of the direct sound, whether in its timbral or spatial features. Results exhibit the variation of the threshold depending on the type of stimulus, as well as on the spatial configuration of the direct sound and the reflection. For a given condition, the perceptibility threshold is given as a directivity function depending on the direction of incidence of the reflection.The second topic deals with room correction methods. Firstly, state-of-the art digital methods are investigated. Their main drawback is that they don't consider the specific impact of the temporal and spatial attributes of first reflections. A new correction method is therefore proposed. It uses an iterative algorithm, derivated from the FISTA method, in order to take into account the perceptibility of the reflections. All the processing is carried out in a spatial sound representation, where the spatial properties of the sound are analysed thanks to spherical harmonics
Herreras, Giralda Marcos. "Développement d’un algorithme de restitution des propriétés des aérosols atmosphériques en utilisant la synergie du spectre solaire et infrarouge thermique". Electronic Thesis or Diss., Université de Lille (2022-....), 2022. http://www.theses.fr/2022ULILR013.
Knowledge and monitoring of atmospheric aerosol chemical composition is highly important for the understanding and evaluation of Earth's climate, environmental processes and air quality. The aerosol composition drives the efficiency of interactions with clouds, direct interaction of radiation with the Particulate Matter, impact on marine ecosystem after the aerosol deposition, etc.. Mineral dust represents the second, after the marine aerosol, largest fraction of the global atmospheric aerosol emissions. The net radiative effect of the atmospheric dust depends on its mineralogical composition. The vast variety of soil mineralogy determines the variability of airborne dust composition, but direct link between them is not evident. Mineralogical composition of volcanic ash is even less predictable, while has an importance for aviation safety. Finally, the fraction of aerosol hygroscopic species is determinant for aerosol cloud interactions. The objective of this thesis is to establish a framework for the combined and consistent retrieval of atmospheric aerosol optical properties and aerosol components using synergy of solar and Thermal Infrared (TIR) measurements. The implementation is done as part of the GRASP algorithm (Dubovik et al., 2021). Synergy between both parts of the spectra is expected to provide an enhanced sensitivity to aerosol microphysical properties as well as a finer characterization of the mineral dust components, e.g. Quartz and clays fractions separation. The presented development is an extension the of previously developed GRASP/Components approach (Li et al., 2019). An important update has been done on the incorporation of Planck emission into the Successive Orders of Scattering radiative transfer scheme that is employed in the GRASP algorithm. In addition, line-by-line and K-Distribution methodologies to integrate gas absorption lines and a methodology to deal with the highly varying aerosol refractive index in TIR was implemented in order to fulfill the objectives. Synthetic tests were performed to evaluate the accuracy of (i) the designed methodology for the measurements simulation of a thermal infrared radiometer and (ii) the updated aerosol components parameterization. Furthermore, a synthetic study was conducted to evaluate the influence of a priori assumed information. An enhancement of the sensitivity to the coarse mode particles, a finer characterization of the dust components, the retrieval of the Aerosol Mean Height (AMH) from passive measurements and finally the retrieval of total column water vapor concentration was illustrated as possible based on the Solar-TIR measurements synergy. Namely, the new combined solar-TIR GRASP/Components retrieval algorithm was applied to the AERONET (AErosol RObotic Network) (Holben et al., 1998) sun photometer and the CLIMAT Thermal Infrared radiometer (Legrand et al., 1999; Brogniez et al., 2003) combined measurements conducted by LOA in Senegal. The observations conducted between November 2020 to April 2021 at the Dakar Belair site were selected for the application of the Solar-TIR GRASP/Components retrieval. A high degree of agreement was found between the derived values and the corresponding standard AERONET retrievals. Moreover, it was found that the total column water vapor and AMH can be retrieved simultaneously with the aerosol characteristics. The retrievals showed good correlation with the independently derived AERONET precipitable water and a qualitative agreement with lidar aerosol profiles observations. The future steps of this work include a further validation of the retrieved aerosol components. The perspective is in the algorithm application to combined 3MI and IASI-NG sensors that will fly onboard of MetOp-SG A space mission or similar
Ferré, Marcel. "Developpement de methodes numeriques et experimentales pour la restitution des profils de temperature dans les verres par teledetection infrarouge". Poitiers, 1988. http://www.theses.fr/1988POIT2289.
Sivira, Ramses. "Exploitation des mesures "vapeur d'eau" du satellite Megha-Tropiques pour l'élaboration d'un algorithme de restitution de profils associés aux fonctions de densité de probabilité de l'erreur conditionnelle". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2013. http://tel.archives-ouvertes.fr/tel-01025685.
Sivira, Figueroa Ramsès Gregorio. "Exploitation des mesures "vapeur d'eau" du satellite Megha-Tropiques pour l'élaboration d'un algorithme de restitution de profils associés aux fonctions de densité de probabilité de l'erreur conditionnelle". Paris 6, 2013. http://www.theses.fr/2013PA066723.
We designed a methodology that allows us to develop a purely statistic water vapor profile restitution algorithm from Megha-Tropiques SAPHIR and MADRAS instruments with synthetic observations, and specially to quantify the restitution of conditional uncertainties. Three statistical models were optimized using this learning database to estimate seven layers tropospheric water vapor profiles and their conditional error probability density function (pdf). The optimized models lead us to conclude a model-independency restitution accuracy and this accuracy is directly related to physical constraints. Also, maximal precision was achieved in mid-tropospheric layers (maximal bias: 2. 2% and maximal correlation coefficient: 0. 87) while extreme layers show degraded precision values (at surface and the top of the troposphere, maximal bias: 6. 92 associated to a fort dispersion with correlation coefficient: 0. 58), this behavior could be explained by instrumental information lack. From conditional error probability functions, knowing observed brightness temperatures, humidity confidence intervals were estimated by each layer. The two hypotheses were tested and we obtained better results from the Gaussian Hypothesis. This methodology was tested using real data and results are consistent with the learning database with better accuracy (bias: -5. 77%) at mid-tropospheric layers, degrading it to extreme layers
Nehaoua, Lamri. "Conception et réalisation d’une plateforme mécatronique dédiée à la simulation de conduite des véhicules deux-roues motorisés". Thesis, Evry-Val d'Essonne, 2008. http://www.theses.fr/2008EVRY0045/document.
This thesis deals with the design and realization of a dynamic mechanical platform intended to the motorcycle riding simulation. This dissertation is organized into several principal sections. First, a literature review is conducted to identify the driving simulation problematic in a general way by focusing on the simulator design. In this part, it was aware of the various mechanical architectures used previously as well as the related limitations. The choice of the simulator‘s mechanical architecture of is driven by the needs to have an sufficient perception during simulated driving situation. Our goal is to reproduce the most relevant inertial effects (acceleration, torque, ..) perceived in a real world driving. The second chapter discusses an exhaustive comparison between automotive vehicles dynamics against the two-wheeled vehicles against. Existing motorcycles dynamic models are adjusted and of have been adapted to meet our needs in terms of privileged inertial cues. The third chapter presents the design aspects, mechanical realization, characterization and identification of the motorcycle simulator developed within the framework of this thesis. It constitutes the main contribution of this research works. Finally, the last two chapters are dedicated to motion cueing /control algorithms and open-loop experimentation on the simulator’s platform. These tests were performed for the characterization and validation of performance of the entire simulation loop
Chang, Yuyang. "Développement d'un nouvelle technique de mesure du profil atmosphérique en aérosols à l'aide d'un lidar Raman-dépolarisation-fluorescence". Electronic Thesis or Diss., Université de Lille (2022-....), 2023. https://pepite-depot.univ-lille.fr/ToutIDP/EDSMRE/2023/2023ULILR060.pdf.
Vertical information on aerosol optical and microphysical properties is of significant importance to study aerosol evolution, transport, as well as their impacts on human health, local environment and global climate. This thesis developed an algorithm, the Basic algOrithm for REtrieval of Aerosol with Lidar (BOREAL), for retrieving heigh-resolved aerosol microphysical properties from combinations of extinction, backscattering and depolarization lidar measurements. Based on maximum likelihood estimation, the retrieval algorithm uses a nonlinear iteration approach to search for the best fit to both measurements and constraints. The retrieved aerosol microphysical properties include particle size distribution, volume concentration, effective radius, complex refractive index (CRI) and single scattering albedo (SSA).The performance of BOREAL, retrieval accuracy and measurement sensitivity are assessed through simulated data. In general, retrieval accuracy is higher for fine-mode particles than coarse-mode particles. The simulations demonstrate the importance of exploiting a priori constraint to improve the retrieval accuracy of CRI and SSA. Apart from spherical particles, performance of retrieving non-spherical particles is also evaluated by integrating three different particle scattering models, i.e., the Sphere, Spheroid and Irregular-Hexahedral (IH) models, into BOREAL. The results show incorporating depolarization measurements into inversion is essential to better constrain and stabilize the retrieval. Besides, approximating non-spherical particles to spheres will evidently degrade retrieval quality in cases of lidar measurements. In addition, BOREAL is applied to real lidar observations of different aerosol types, including biomass burning, dust and continental polluted aerosols at the ATOLL observatory. Results are analyzed and compared with retrievals from AERONET and previous studies, which demonstrates the robustness of BOREAL for real data application and aerosol characterization.Overall, this work contributes to Labex CaPPA and ACTRIS efforts to better quantify aerosol microphysical properties using lidar measurements
Ghasemi, Navid. "Improvement of the driving simulator control and comparison between driver-road-vehicule interaction in real and simulated environment". Thesis, Paris Est, 2020. http://www.theses.fr/2020PESC2010.
The related research activities were carried out in collaboration with the University of Bologna, Paris-Est University and Gustave Eiffel University (IFSTTAR) in the form of a cotutelle PhD. The activities are divided into two macro areas ; the driving simulation studies conducted in Gustave Eifel University (IFSTTAR) and on-road experiments organized by the University of Bologna. The first part of the research is focused on improving the physical fidelity of the two DOF driving simulator with particular attention to motion cueing and vehicle dynamics model. The vehicle dynamics model has been developed in MATLAB-Simulink and has the ability of real-time calculation of the vehicle states and control the motion platform. During this phase of the research, motion cueing algorithms were developed to control the simulator movements and the effect of the motion cues on drivers’ behaviour was analysed through experimentation. The results of these studies are discussed in the case studies I and II. In the second part of the research, the driver performance and visual behaviour were studied on the road under different scenarios. The driver visual behaviour was recorded with the use of a head mounted eye-tracking device, while the vehicle trajectory was registered with an instrumented vehicle equipped with Global Positioning System (GPS). During this phase, several case studies were developed to monitor drivers’ behaviour in the naturalistic environment. Case study III aims to integrate the traditional road safety auditing with an innovative driver behaviour monitoring system. The real road experiment with drivers was carried out in an urban arterial road in order to evaluate the proposed approach through innovative driver monitoring techniques. These same driving monitoring instruments were used for evaluating the improvement of a pedestrian crossing at the roundabout in case study IV. The eye-tracking data were evaluated in both studies in order to identify a driver visual attention indicator based on the participants gaze position and duration. Significant attention is given to the safety of vulnerable drivers in urban areas during the naturalistic driving behaviour study. Case study V analyzed the driver yielding behaviour in approach phase to a bicycle priority crossing with the use of surrogate safety measures. The drivers’ performance measures such as perception reaction time and gaze behaviour were used to assess the safety level of the crossing equipped with standard and innovative signalling systems. The improvement on the driver’s yielding behaviour towards an un-signalized crossing during night-time and their reaction to an integrated lighting-warning system was evaluated in the case study VI. The last phase of the thesis is dedicated to the study of Adaptive Cruise Control (ACC) with on-road and simulator experimentation. The on-road experimentation investigated the driver assistant system influence on the drivers' adaptation with objective and subjective assessment, in which an eye tracking instrument and EEG helmet were used to monitor the drivers on a highway. The results are presented in Case studies VII and VIII and drivers’s visual attention was reduced due to adaptation to the ACC in the car following scenario. The results of the on-road test were later used to reproduce to the same scenario in the driving simulator and the adaptation of drivers’ behaviour with the use of ACC was confirmed through experimentation
Vishwakarma, Pragya. "Méthodes innovantes pour la restitution des propriétés des nuages à partir du radar BASTA". Electronic Thesis or Diss., université Paris-Saclay, 2022. http://www.theses.fr/2022UPASJ009.
Clouds are critical to the majority of aspects of human existence on earth. They also have a significant impact on the earth's energy balance. Although the effect of clouds on the climate is complex and not fully understood, much of the uncertainty about global warming is related to the cloud-climate feedback problem. Studies have shown that the representation of low-level clouds is still underestimated in various climate models. The necessity to examine the cloud properties at different levels has emerged as a priority in earth observation. Continuous and detailed observations of clouds are needed to characterize the cloud properties on a local and global scale. Active remote and passive sensing instruments like cloud radars, lidars, visible and microwave radiometers, etc., have the advantage of continuous observation for long periods from the ground or space.One of the fundamental parameters to characterize the microphysical properties of these low-level clouds is the liquid water content (LWC). This thesis aims at developing an algorithm estimating LWC in low-level clouds using cloud radar and microwave radiometer (MWR) synergy when the latter is available. A 95GHz cloud radar measures the backscattered energy from cloud droplets in terms of radar reflectivity factor (Z). In the Rayleigh regime, Z is considered proportional to the sixth moment of droplet size. Traditionally, empirical relations following a power law such as Z=aLWCb are used to retrieve the LWC of low-level liquid clouds. However, such relationships do not always represent the variability of drop size distribution in a heterogeneous cloud system and do not account for liquid cloud attenuation. In this thesis, I propose using the same concept, but the constraint on ‘a’ from the power law is released by adding extra information such as the liquid water path (LWP). Studies have shown that the accuracy of LWC estimates can be increased by incorporating additional information from an independent remote sensing instrument like a microwave radiometer (MWR) in the retrieval method.My retrieval algorithm is based on probabilistic estimation theory called the variational approach. Thanks to this flexible framework, when liquid water path (LWP) information from MWR is assimilated, the LWC in the profile is scaled by LWP information, and the scaling factor (lna) can also be retrieved for each profile. To test the behavior of the retrieval algorithm, a sensitivity analysis for perturbations in key parameters using synthetic fog profiles from AROME simulation is conducted. The analysis has shown that the algorithm is very sensitive to the bias in LWP because it is a vertically integrated information and thus plays a critical role in the retrieval. Other parameters, such as 'b' and alternative attenuation relationships, have less implications on the stability of the algorithm.Because the sensitivity test is not validating the microphysical assumptions of the method,the validation of such an algorithm is challenging, as we need reference measurements of LWC co-located with the retrieved values.During the SOFOG-3D campaign (South-West of France, October 2019 to March 2020), in-situ measurements of LWC were collected in the vicinity of a cloud radar and a microwave radiometer, allowing comparison against my retrieved LWC. The comparison showed better agreement with in-situ observations for stratus clouds than fog. The comparison also demonstrated that cloud-fog heterogeneity is an important factor in the assessment. Finally, the retrieval algorithm is employed to build a climatology of LWC and lna for 39 cloud and fog cases from November 2018 to May 2019 at the SIRTA observatory. Since the retrieval method must be usable without radiometer information, we propose using this climatology as a priori knowledge for the scaling factor, which is no longer constrained by LWP
Coudon, Julien. "Algorithmes de commande pour le pilotage d'une direction découplée". Phd thesis, Grenoble INPG, 2007. http://www.theses.fr/2007INPG0014.
This dissertation focuses on the problem of the control of a Steer-Sy Wire System. The main idea is to control the two subsystems the steering wheel one and the front wheels one) which composed the steering system in order to : give to the driver, thanks to the steering wheel, relevant information about the dynamic status of his vehicle ; provide comfortable driving feelings ; improve the vehicle dynamics. This study presents a reference model which describes the desired behavior of a steering system in interaction with a vehicle. This model accounts for force reflection and vehicle dynamics interactions. Two control law strategies are proposed to reproduce the behavior of the reference model on the steering system. Experimental results on prototype are exposed
Coudon, Julien. "Algorithmes de Commande Pour Le Pilotage d'Une Direction Découplée". Phd thesis, Grenoble INPG, 2007. http://tel.archives-ouvertes.fr/tel-00181462.
Deux méthodes de commande sont proposées afin de reproduire le comportement du modèle de référence sur un système de direction découplée. Des essais sur prototype ont été réalisés et des résultats expérimentaux sont proposés.
Tinel, Claire. "Restitution des propriétés microphysiques et radiatives des nuages froids et mixtes à partir des données du système RALI (RAdar-LIdar)". Phd thesis, Université Paris-Diderot - Paris VII, 2002. http://tel.archives-ouvertes.fr/tel-00004241.
Franquet, Sarah. "Contribution à l'étude du cycle hydrologique par radiométrie hyperfréquence : algorithmes de restitution (réseaux de neurones) et validation pour la vapeur d'eau (instruments amsu, saphir) et les précipitations (AMSU, radars au sol baltrad)". Paris 7, 2003. http://www.theses.fr/2003PA077045.
Houda, Taha. "Human Interaction in a large workspace parallel robot platform with a virtual environment". Electronic Thesis or Diss., université Paris-Saclay, 2020. http://www.theses.fr/2020UPASG047.
The thesis objective relates to the denition, the implementation and the evaluation of a Motion Cueing Algorithm taking into account the perceptual constraints of the vestibular systemin humans and the constraints related to the movement physics of the used simulator. The latter consists of a series-parallel robotic platform with 8 degrees of freedom, entirely designed in the laboratory and intended primarily to assist people with motor disabilities. This sensory restitution requires multidisciplinary research work in robotics and virtual reality. Moreover, a formalization of dynamic modeling, based on the state of the art, was adapted and the dynamic parameters optimized and identied for the 8 degrees of freedom motion platform. Several methods of trajectory generation, exploitation of the platform redundancy, have been studied, implemented,and compared. The most e cient particle swarm optimization (PSO) method was chosen. This algorithm is then used to optimize the parameters of the platform controller in sliding mode. The simulator was used for a virtual reality ski application reproducing the Combloux resort in Haute-Savoie dedicated to disabled people. The simulation results show a very good trajectory tracking behavior and a good reduction in terms of oscillations. This work will be continued through the use of multi-sensory human-assisted virtual reality interfaces
Rengifo, cadavid Carolina. "Contrôle plateforme pour la validation du véhicule autonome sur simulateur dynamique à hautes performances". Thesis, Paris, HESAM, 2020. http://www.theses.fr/2020HESAE023.
The work presented in this manuscript takes part in the context of driving simulation and more specifically in the one of dynamic driving simulators used for the validation of advanced systems and the autonomous vehicle. In order to address the issues of performance and motion perception, we have presented different approaches to improve the Motion Cueing Algorithms (MCA). All our studies show that the model predictive control (MPC) strategy is the best choice to MCA on high-performance driving simulators. Indeed, compared to other strategies, it allows to better take advantage of the workspace without endangering the simulator and/or the driver. However, in this MCA, the real-time optimization and the perception model must be guaranteed in order to improve the driver's immersion in the virtual environment. Therefore, we compared different techniques to solve constrained optimization problems. We proposed a based optimization technique, which provides an intuitive and fast solution to the MPC constrained optimization problem. Finally, we established recommendations for MCA parameterization according to the self-declared driving behavior allowing a better perception of motion in a driving simulator, in interactive driving and in autonomous mode
Loyet, Raphaël. "Dynamic sound rendering of complex environments". Phd thesis, Université Claude Bernard - Lyon I, 2012. http://tel.archives-ouvertes.fr/tel-00995328.