Дисертації з теми "Formation hybride de faisceaux"
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Paquien, Lucien. "Transmetteur intégré bidirectionnel dédié à la 5G mmW dans un système de formation de faisceaux hybride et numérique." Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0064.
The increasing demand for data rate for mobile telecommunications has led to the use of beamforming systems in order to notably limit the impact of free space propagation losses (FSPL) over the link budget, due to the elevation of the operating frequency. In order to be able to direct a directional beam concentrating the majority of the gain of the antenna array towards a given user, a large number of integrated radio frequency front-ends (RFFE) is necessary.Conventionally, 5G RFFEs generally consist of a low noise amplifier (LNA), and a power amplifier (PA). The latter are physically dissociated, and are alternatively addressed using a commuted element, in order to operate in time division duplexing (TDD). In this case, not only does the switched element involve losses and a significant silicon surface requirement, but also the RFFEs are only used half the time (due to TDD). Also, this large silicon area required must then be multiplied by the number of elements that constitutes the beamforming system. In addition, the spacing between each antenna constituting the antenna array being proportional to the wavelength, the latter could therefore reach higher operating frequencies if the RFFEs are miniaturized. In this work, a solution allowing the elimination of the need for a commuted element, as well as the merging of the LNA and PA is proposed, inducing a strong reduction in the silicon surface area required for the same operation that conventional architectures, using the GF 22nm CMOS FD-SOI technology. Although the design of millimeter functions (mmW) will be discussed, the frequency conversion aspect as well as the study of baseband functions will also be covered, including the design of a RF passive mixer, two reconfigurable second- and fourth-order active-RC low-pass filters, a variable gain amplifier (VGA), a 50Ω analog buffer, a double pole double throw (DPDT) switch, as well as a generation chain of quadrature signals, done from the combination of a hybrid coupler (HCPLR), and an external off-chip local oscillator (LO). The complete system will be simulated to demonstrate the relevancy of these structures regarding performances and required silicon surface, and axis for improvement will also be listed
Oueslati, Aymen. "Nouveau concept simplifié d’antennes reconfigurables utilisant les couplages interéléments : Mise en œuvre d’un réseau hybride." Thesis, Limoges, 2015. http://www.theses.fr/2015LIMO0136/document.
The work of this thesis aims to investigate a new concept of reconfigurable antenna allowing a good trade-off between performances, complexity and cost. This concept is called ‘hybrid’ because it is based on the capabilities of thinned arrays and parasitic element antennas. It is an alternative to classical antenna arrays and their complexity. The proposed concept has a modular architecture, and a good versatility for reconfigurable beams. The main advantage of this hybrid antenna is the simplicity of its beam formation network (BFN) which requires only a few number of excited elements. The antenna uses parasitic elements to manage the effects of couplings between the electromagnetic access. The problematic of active VSWR is also solved at the antenna level, avoiding the use of additional components in the BFN. This work details the principle of the reconfigurable hybrid antenna concept. The potentialities are evaluated. The elements required to realize a proof of concept are then defined, using a dedicated experimental setup. A prototype is manufactured and the performances have been checked to validate this innovative concept
Letailleur, Lucas. "Éléments d'architecture d'émetteur linéarisé en technologie GaN pour des applications 5G millimétrique." Electronic Thesis or Diss., Université Gustave Eiffel, 2023. http://www.theses.fr/2023UEFL2073.
This thesis focuses on architectures and circuits for 5G FR2-1 communication systems. These systems operate in millimeter waves and use massive Multiple Input Multiple Output (MIMO) techniques. A gallium nitride (GaN) power amplifier (PA) from Macom is characterized and modelled. The results show that the PA do not meet the requierements of the 5G FR2-1 standard. A digital predistorsion (DPD) and an analog predistortion (APD) are therefore investigated and compared. DPD offers better linearization performance than the APD, but cannot linearize bandwiths grater than 100 MHz. The APD, on the other hand, allows to linearized a signal with a bandwidth up to 400 MHz on the n258 frequency band, and can be co-integrated with the PA. Both linearization techniques enable the amplifier to meet the requirements of 5G FR2-1 standard. The use of massive MIMO suggests that conventional architectures need to be reviewed. Consequently, a new approach for sizing the critical elements of the emission architectures is proposed. The main objective is to find the most suitable trade-off between the emitted power, linearity and the consumption of the overall architecture. For beamforming, a Butler matrix, using the same substrate as the power amplifier, is designed, and a new architecture is investigate. The architecture uses a co-design of a single power amplifier, a switch and a Butler matrix network, and enables 32 radiating elements to be fed. Finally, a comparative analysis of low-noise amplifiers based on GaN and gallium arsenide (GaAs) is carried out and a figure of merit is proposed. This study shows that it is possible to use the same technology for all front-end elements
Milbrandt, Jorick. "Études de nouvelles architectures d’antennes hybrides reconfigurables." Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0121.
The works presented in this thesis focus on the study of reduced BFN reconfigurableantennas (ARFFR). The concept of ARFFR generalizes the works of Harrington onelectronically steerable parasitic array radiator to regular arrays composed by excited elementsand parasitic ones. This approach aims to simplify the BFN of these antennas in order todemocratize competitive reconfigurable antenna arrays. Thanks to the use of reactive loadsconnected to parasitic elements, controls are maintained to manage both beam forming andactive matching. This thesis aims to assess the performances of the ARFFR and to developantenna architectures which permit to attain complex functions. The scope of application ofARFFR is defined and a design methodology is proposed. This work details the principle ofARFFR concept and analyses the potentialities of a Ku-band ARFFR. The digital approachused to design ARFFR is validated thanks to a demonstrator. Finally, the potentialities of thisconcept are refined by the study of orthogonal bipolarization
Jedrkiewicz-Owczarek, Floriane. "La formation hybride : entre conception et usage." Thesis, Paris 1, 2022. http://www.theses.fr/2022PA01E012.
The concept of hybrid training, combining activities in presence and distance, most often supported by a digital platform, before 2020 was a niche solution, little recognized. It was forcibly democratized with the covid-19 pandemic, even forcing the emergence of a new form of hybridization where the two modalities merge. The first definition of hybrid training appeared in 1995, written by Didier Valdès in his thesis for Paris 2 Panthéon Assas. He pointed out a certain number of criteria essential to the design of such training. However, the historiography concerning the study of these, from a erspective of definition, evaluation and design, was quickly turned upside down by the emergence of web 2.0. The design criteria adopted became more and more numerous and technical, the authors interviewing only a part of the actors (teachers or students), without a global vision and without taking into account their real activity. This approach, not integrating the activity of their operators, leads to complex hybrid training courses to be followed both for students and teachers, who may even be resistant to Information and Communication Technologies (ICTs). ) employees, or even to training in general. We are therefore looking to observe a hybrid training taking into account the activity of the operators, in order to deduce design tracks more in line with it. We employ an ethnocentric methodology, based on the theoretical framework of the activity, with an associated method - in particular the notions of prescribed and real. We thus seek to go beyond the usual dichotomies with machine / without machine, and presence / distance. We refer particularly to the activity theory developed by Yrjö Engeström, and to the instrumental theory of Pierre Rabardel. We observe a hybrid module of initiation to information and Pix certification within a university course More specifically, we have retained for the analysis a chapter of the course comprising a 1h30 face-to-face session and work to be done remotely. All the data available over this observation period is used, i.e. a heterogeneous set including open observations in class, video recordings, interviews carried out with users and designers, questionnaire for students, collection of emails from the teacher, data generated through the IT platform, and presence on student workspaces and exchanges such as Facebook and Google Drive. These data are combined in quantitative and qualitative ways, and analyzed through the production of detailed chronologies, Engeström contradiction tables, and a revised version of Gaëtan Bourmaud's Method of Failures and Substitutions of Resources (MDSR). We highlight a clear gap between prescribed and actual training (that is to say between training designed and in situ), resulting from a design in use carried out by the actors - teachers and students. This implies paradigm shifts, particularly with regard to student autonomy, the objective of the training which disrupts the position of the teacher. This conception in use is the result of a collective work of the operators (teacher and students), practically leading to a redesign of the training according to the needs actually felt. The design of a hybrid training in accordance with this activity would thus suppose to use the distance for what it is, in order to facilitate the creation of a community of university learning
Meghdadi, Hamid. "Formation de faisceaux coopératifs pour transmissions multiutilisateurs par relais." Limoges, 2011. https://aurore.unilim.fr/theses/nxfile/default/6bc3bf02-a1af-45ee-bf57-bee7da961fd7/blobholder:0/2011LIMO4041.pdf.
The demand for high speed reliable communication systems will never stop increasing. Many challenges face researchers trying to provide such systems and schemes. Cooperative networks have been successfully used to enhance the performance of telecommunication systems. Among different cooperative strategies, distributed cooperative relaying have shown to be a promising scheme. This dissertation addresses the problem of optimizing the precoding vectors in order to improve the system performance of multi-user multi-relay cooperative networks. Precoding vectors are used to cancel out the multiple access interference, maximize the signal to noise ratio at the destination, and optimize the power allocation at relaying stations
Sanojca, Elzbieta. "Les compétences collaboratives et leur développement en formation d’adultes : le cas d’une formation hybride." Thesis, Rennes 2, 2018. http://www.theses.fr/2018REN20001/document.
The competences to cooperate/collaborate are amongst the first to be developed in many educational frameworks. Within digitized societies, they promise efficiency, innovation, and well-being at work. However, these competences are not put forward in profesionnal organisations, and they are lacking from adult training courses.Based on this observation, this thesis aims at identifying the competences to be developed to work more easily with others. Bringing light on the abilities to act, convienently called “collaborative competences”, and on the way which they can be developed through training are the objects of this study.Thoroughly analysing the context of a hybrid training is carried out based on the study of the profesionnal trainingcourse “Animacoop: animating a collaborative project” which concerned 200 interns from 2010 to 2014. In this study, collaborative competences are analysed in link with profesionnal experiences and collaborative projects.Falling within an empirical approach, the research methodology connects a few data collecting tools (questionaires, interviews, observations) and on a conceptual level mobilises the Activity Theory and the notion of Training System .This research offers a model of key competences to lead a collaborative project. It analyzes the training system as a strong internally coherent ecosystem, open to development, prone to creativity, which favors collaborate competences development
Darjo, Valerie <1977>. "Formation hybride et cooperation universitaire nord-sud pour le developpement." Doctoral thesis, Università Ca' Foscari Venezia, 2014. http://hdl.handle.net/10579/6534.
Roy, Bruno. "Formation de faisceaux laser avec moment angulaire orbital : fabrication de lames de phase en spirale réflectrices." Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/27771/27771.pdf.
Forero, Romero Jaime Ernesto. "Predictabilité, galaxies infrarouges et lentilles gravitationnelles : applications de l'approche hybride." Lyon, École normale supérieure (sciences), 2007. http://www.theses.fr/2007ENSL0427.
Blaizot, Jérémy. "Formation et évolution des galaxies à grand décalage spectral : développement de l'approche hybride." Paris 11, 2003. http://www.theses.fr/2003PA112322.
This thesis presents a model of galaxy formation in which the formation of dark matter structures is described with cosmological N-body simulations and the fate of baryons is treated in a semi-analytic fashion. We show how mock observations can be made in order to directly confront the model's predictions with observations. This method is then applied to a detailed study of high-refshift Lyman break galaxies, and used to investigate the nature of the galaxy spatial distribution in the local universe
Blanc, Stéphane. "Architectures optiquespour la formation de faisceaux multiples à la réception : applications aux antennes radar." Grenoble INPG, 2004. http://www.theses.fr/2004INPG0101.
The evolution of radar systems as well as telecommunication satellites induces the need of simultaneous multibeams for the receive mode. In this thesis we propose two new optical beamforming architectures for the receive mode in network antennas. The former is based on the fiber chromatic dispersion, whereas the latter is an optical coherent architecture based on an optical dual-frequency source. These architectures were firstly analyzed theoretically and secondly their performances were measured. Both are based on two technological blocks that have been studied too: the optical summation and dual frequency optical source locked on a local oscillator. The dynamic behavior of the optical summation was modeled and various technological solutions based respectively on a coupler, a multiplexer or a fiber summation was presented. The WDM channel influence and the interference between optical carriers were analyzed theoretically and experimentally. The optical summation models were applied to summation through a WDM and the theory is in agreement with the measure. As in the case of microwave summation, the optical summation allows a gain on the dynamic range. Then we present the theory allowing to conceive a dual frequency laser locked on an electric signal. The results are very promising, indeed thanks to the use of two lock loops, a stability of about an hour was observed
Kurisummoottil, Thomas Christo. "Sparse Bayesian learning, beamforming techniques and asymptotic analysis for massive MIMO." Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS231.
Multiple antennas at the base station side can be used to enhance the spectral efficiency and energy efficiency of the next generation wireless technologies. Indeed, massive multi-input multi-output (MIMO) is seen as one promising technology to bring the aforementioned benefits for fifth generation wireless standard, commonly known as 5G New Radio (5G NR). In this monograph, we will explore a wide range of potential topics in multi-userMIMO (MU-MIMO) relevant to 5G NR,• Sum rate maximizing beamforming (BF) design and robustness to partial channel stateinformation at the transmitter (CSIT)• Asymptotic analysis of the various BF techniques in massive MIMO and• Bayesian channel estimation methods using sparse Bayesian learning.One of the potential techniques proposed in the literature to circumvent the hardware complexity and power consumption in massive MIMO is hybrid beamforming. We propose a globally optimal analog phasor design using the technique of deterministic annealing, which won us the best student paper award. Further, in order to analyze the large system behaviour of the massive MIMO systems, we utilized techniques from random matrix theory and obtained simplified sum rate expressions. Finally, we also looked at Bayesian sparse signal recovery problem using the technique called sparse Bayesian learning (SBL). We proposed low complexity SBL algorithms using a combination of approximate inference techniques such as belief propagation (BP), expectation propagation and mean field (MF) variational Bayes. We proposed an optimal partitioning of the different parameters (in the factor graph) into either MF or BP nodes based on Fisher information matrix analysis
Benzerrouk, Ahmed. "Architecture de contrôle hybride pour systèmes multi-robots mobiles." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2011. http://tel.archives-ouvertes.fr/tel-00669559.
Noblet, Jean-Pierre. "L'appropriation d'un dispositif hybride en formation pour adultes : le cas du Campus numérique à l'ESSCA." Thèse, Université de Sherbrooke, 2009. http://hdl.handle.net/11143/5779.
Fezai, Faycel. "Synthèse d’architectures d’antennes à éléments parasites pour la formation de faisceaux : Application au projet Remote Wake Up (RWU)." Limoges, 2013. http://aurore.unilim.fr/theses/nxfile/default/b3ec72a4-c702-4c10-b6a5-3e0e05e8d54d/blobholder:0/2013LIMO4044.pdf.
This thesis revisits parasitic elements antennas and offers innovative and effective synthesis design strategies. The main objective of this work is to reveal the full potential of these antennas in order to promote their dissemination. Parasitic elements antennas are presented as cost-effective solutions to achieve beamforming. A dedicated synthesis technique has been developed to obtain performances close to those of antenna arrays, without the disadvantages of a feed distribution network. The latter is complex, expensive and sensitive to manufacturing dispersions, making arrays difficult to design as cost-effective antennas. In this manuscript, generic architectures of parasitic elements antennas are developed. Particular points of versatility, reliability and ease of manufacture have been addressed in order to comply with the requirements of industrial processes. A demonstrator of a reconfigurable parasitic elements antenna has been designed, fabricated and characterized. The successful demonstration allows considering reconfigurable low cost antennas. The skills developed in this thesis have been applied in the context of energy saving in the framework of the Remote Wake Up project (RWU), dedicated to the minimization of standby mode electrical consumption. High efficiency integrated antennas were developed for wireless energy transfer
Bekkar, Mohammed. "Formation de voies hybride analogique-numérique pour la réduction d'interférences dans les réseaux cellulaires de nouvelle génération." Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALT007.
Beamforming is a signal processing method used in antenna arrays, allowing to enhance directions of emission or reception of signals by controlling the different elements.In mobile networks especially, it allows interference reduction in base stations.Its full digital impementation is limited by energy consumption and cost when increasing the number of antennas.As a response, hybrid analog-digital implementation could be used to reduce the number of radiofrequency (RF) chains as well as the number of analog-to-digital converters.In this implementation, the analog stage could be realised using different types of devices (phase shifters, amlifiers/attenuators, variable impedances) and with a variable connectivity to the antenna array.Nevertheless, if we want to keep a simple RF circuitry by using phase shifters only to tune the analog beamformer, the problem of optimising these weights becomes non-convex.The current works on small cell networks show that the interference between base station is one of the limiting factors of the coverage and the datarate.Furthermore, in a full digital implementation, the presence of strong blockers leads to analog-to-digital converters saturation or desensitization.The purpose of this work is the study of hybrid beamforming with phase-only implementation, as well as to propose an algorithm to compute the beamforming matrices, to reduce the received interference in a small cell.After a description and a state-of-the-art, we preliminarily proposed an interference characterization using an algebraic angle between the signals of interest vectors and the interference vectors, which allowed us to obtain a lower bound on the SINR performance of the optimal beamformer.We have then proposed a sub-optimal solution of hybrid phase-only beamforming, which when using an infinite resolution digitization, has a low loss as compared to a solution using modulus and phase.Secondly, we introduced an analog-to-digital converter model, which allowed us to bring out the limitations of the first appproach as well as of the full digital implementation, in the presence of strong blockers.Afterwards, we proposed an optimisation algorithm of the analog stage, based on a semidefinite relaxation.The peroformance of this algorithm, in terms of SINR and sumrate are close to the benchmark with full degree of freedom, modulus and phase.In comparison, the performance state-of-the-art tested solutions using non-convex cost function are lower and depend on initialization point
Fourny-Arrivé, Sandra. "Contenu de marque : nature de la pratique et tensions associées à la formation d'une stratégie marketing hybride." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLED025/document.
Brand content refers to editorial contents that are produced by the brand itself. This form of communication appears to be disruptive compared to traditional advertising as it does never mention the product and thus does not appear to intend to sell anything to the consumer. The objective is more to seduce the audience with an interesting and entertaining content. Our research aims at understanding brand content strategies, as well as its actors and logics.Twenty individual interviews with communication experts and two brand case studies have been implemented.We propose a conceptualization of brand content, as well as a typology of existing practices. We explain the formation of the strategy and the logics of actors participating to the formation. We illustrate the fact that strategy can be formalized (deliberate) or that it can also arise from non-planned initiatives. We finally present the tensions emerging from the strategy formation.Our research contributes to both brand management and strategy as practice literatures
Vandelle, Erika. "Exploration de solutions antennaires et de formation passive de faisceaux pour la récupération et le transfert d’énergie sans fil." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT060.
Wireless energy harvesting (WEH) of ambient or intentional electromagnetic power sources of frequency ranging from 100 MHz to 10 GHz, has appeared as a promising solution to develop self-powered electronics in the past decades. However, the low power densities available, usually lower than 1 uW.cm-2, result in a limited RF-to-DC conversion efficiency and sensitivity of the energy harvesting system (rectenna) and the ambient signal diversities (unknown and time-varying direction of arrival, polarization) prohibit the use of directive antennas.In this thesis, the power combination techniques of Radio Frequency (RF) or Direct Current (DC) power in multi-antenna WEH systems, together with original structures, are investigated to address those challenges. Besides, a new Figure-of-Merit (harvesting capability) for rectennas operating in ambient scenarios is derived with probabilistic terms representing the frequency, polarization and spatial diversities of ambient signals.The first part of this thesis focuses on the design of efficient antenna and rectenna elements. Eco-responsible and low-cost prototypes are proposed by using a paper substrate along with an original strategy for the reduction of the losses.In the second part of this work, the rectification efficiency of a WEH system is enhanced through the combination of the RF power prior to the rectification process, without reduction of the spatial coverage. For this, a 3D multidirectional structure of scanning antenna arrays using passive beam-forming networks is designed to obtain a multidirectional high gain aggregate pattern. This radar-inspired solution involving Butler matrices results in a highly efficient RF-to-DC power conversion along with an optimal angular coverage, which leads to a harvesting capability higher than the state-of-the-art.The last part of this work addresses the limited sensitivity of the RF combination technique compared to that obtained with the series DC combination technique thanks to a reconfigurable system. To this end, modular rectenna unit cells are designed to form a scalable and adaptative interferometric beam-forming network, which offers the possibility to achieve a highly efficient and sensitive WEH system. This solution is suitable for low-power energy harvesting, autonomous passive tracking or RFID applications
Shargaieva, Oleksandra. "Formation and stability of hybrid perovskites." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19530.
Guiraud, Céline. "Algorithmes de formation de faisceaux par le calcul pour un système d'antennes de satellites de télécommunications avec ou sans réflecteur /." Paris : École nationale supérieure des télécommunications, 2001. http://catalogue.bnf.fr/ark:/12148/cb37710953t.
Guo, Jing. "Améliorer la compréhension de l'oral en chinois langue étrangère : quelles compétences développer et avec quel scénario de formation hybride ?" Phd thesis, Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00788294.
Galley, Ghislaine. "Une identité hybride construite dans les interstices organisationnels : le cas des moniteurs des maisons familiales rurales." Thesis, Lille 3, 2019. http://www.theses.fr/2019LIL3H024.
The teaching function has different realities depending on the context of the trade. This may include teaching full time in the initial stages (primary and secondary) or training of future professionals by alternance training methods(CFA, MFR), situations that involve very different professional practices and identities for those in charge. Because of this very variability in training situations, people who are engaged in the teaching function may be faced with professional prescriptions that are far removed from the job they had planned to perform when they mobilized to enter the trade. It is precisely this gap between the occupation of instructor concerned and the one actually occupied that will be discussed in this work.In particular, we will be interviewing modes of engagement in the trade and identity transitions of trainers practising alternance training, working in “Maisons Familiales Rurales” (MFR) after failing National Education recruitment competitions. Recruited in a somewhat incidental way in MFR, the pedagogical prescriptions to which they are subjected are quite distant from those which they anticipated and had internalized for their recruitment by National Education: they share with the teachers of the traineeship the work of training, they accompany the learners in a process of knowledge production, they are not limited to the teaching of a discipline of which they would be experts, for example. Confrontation with a form of education that deviates from that anticipated creates a dissonance all the more important because it is first the consequence of failure and then of a constrained reorientation. This dissonance between the occupation concerned and the occupation actually prescribed is likely to be a source of discomfort.This thesis analyses the vocational positions that trainers by alternance training value to resolve this dissonance, in order to build themselves a subjectively satisfactory professional identity. Studying investment patterns in the MFR instructor trade (preferred practices, professional postures adopted), she intends to report on the identity strategies implemented in the context of relatively plastic organisational structures
Milord, Laurent. "Dispositifs photoniques innovants pour le piégeage optique : Cavité étendue à double période et structure hybride cristal photonique-nano antenne." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI026/document.
Since the first work on optical tweezers by Ashkin, a lot of efforts have been made to trap nanoparticles. However, optical tweezers are diffraction limited and can hardly trap particles below 200 nm. This limit can be overstepped using the optical gradient forces of an evanescent field generated and amplified by a photonic nano cavity. Nonetheless, this approach faces two major issues for applications: the trapping section is very small, making the capture of a Brownian motion animated particle very unlikely, and for the “ultimate” nano antennas with nanometric optical modes, their excitation from free space is not effective. The goal of this work is to overcome these two difficulties. To increase the trapping surface, we will first present a device using slow Bloch modes within a double period extended cavity designed in a photonic crystal made out of SOI. We will show that this approach allow for the trapping of 200, 100 and 75 nm particles on an extended surface of 5x5 µm² using a free space laser beam excitation. Secondly, we will investigate the free space excitation of nanometric structures. A photonic crystal – nano antenna mixed structure will be presented, where the photonic crystal is used as a photon pool for the nano antenna. This lead to a funnel effect where the light coming from a large free space laser beam (5µm wide) is focused into the nano antenna. The trapping of 100 nm particles will demonstrate the relevance of this approach
He, Delong. "Formation de structures hybride de nanotubes de carbone et de microparticules d'alumine par la méthode CVD : mécanismes et cinétiques chimiques." Phd thesis, Ecole Centrale Paris, 2010. http://tel.archives-ouvertes.fr/tel-00504681.
Gerbaud, Stéphanie. "Contribution à la formation en réalité virtuelle : Scénarios collaboratifs et intégration d'humains virtuels collaborant avec des utilisateurs réels." Phd thesis, Rennes, INSA, 2008. ftp://ftp.irisa.fr/techreports/theses/2008/gerbaud.pdf.
GVT is a virtual environment for individual training on industrial procedures such as maintenance procedures. In this thesis, we propose models to extend GVT possibilities to training on collaborative procedures where real users and virtual humans collaborate. We present an activity model for an actor (either real or virtual) which allows him to perform actions depending on his characteristics, on the scenario, on the environment and also on his partners' activity. We also propose an extension to the graphical scenario language LORA in order to describe a collaborative scenario. Such a scenario describes the assignation of people to actions and integrates some collaborative actions. Finally, we present the action selection mechanism we have set up. Its aim is dual: to allow a virtual human to select an action to perform and to give a pedagogical advice to a trainee about the best action to choose
Gerbaud, Stéphanie. "Contribution à la formation en réalité virtuelle : scénarios collaboratifs et intégration d'humains virtuels collaborant avec des utilisateurs réels." Phd thesis, INSA de Rennes, 2008. http://tel.archives-ouvertes.fr/tel-00475589.
Gastaldi, Matthieu. "Développement d'une solution Core-chip MMIC avec convertisseur série-parallèle intégré en technologie BiCMOS pour la formation des faisceaux pour antennes agiles." Thesis, Toulouse, INSA, 2016. http://www.theses.fr/2016ISAT0046/document.
This R&T CNES project concerns the design and realization of a Core-chip MMIC system integrated in SiGe BiCMOS technology. The MMIC core-chip system is dedicated to the beamforming for the active satellite antenna. The new solutions for the satellite payloads being developed for telecommunication applications need an increased flexibility at all the levels. More precisely, the system of active antennas allowing an adjustment by real-time electronic command of the terrestrial covered area offers an optimized response for the communication link budget. This performance has a cost: the necessity of a very large number of RF control points "amplitude / phase" of the beamforming equipment which power the active antenna matrix elements. So, it becomes mandatory to bring a new solution to optimize this function. The main challenges are: increasing the functions integration, decreasing the DC power consumption and keeping the RF performances in terms of gain, resolution and linearity
Braga, A. Judson. "Sondage de Canal SIMO à l'intérieur des bâtiments et formation de faisceaux numérique utilisant des techniques de traitement de signal à haute résolution et corrélateurs cinq-ports." Phd thesis, Télécom ParisTech, 2006. http://pastel.archives-ouvertes.fr/pastel-00002667.
Dellinger, Nicolas. "Modélisation de la formation et de l’évolution des particules de suie en approche hybride Euler-Lagrange pour la simulation de foyers aéronautiques." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS074.
Soot has become an important issue in the design of aeroengine combustors. New certifications on soot particles are to be applied in 2020 due to growing concern about pollutant emissions in the transportation industry. Soot particles also modify radiative heat transfers in combustion chambers affecting thermal load at walls and NOx formation. Still, efficient and accurate prediction of soot particles formation and evolution is an open field in CFD. This manuscript proposes to combine a Eulerian description of soot precursors and a Lagrangian description of particles evolution, which has the advantage to be well suited to follow the evolution of the particle size distribution. The growth of polycyclic aromatic hydrocarbons is modelled by a sectional method to obtain the soot inception rate and create the particles tracked in the gas flow. The particles are described as spheres interacting with the gas through chemical processes and between each other by coalescence, bounded to young liquid-like particles depending on their diameter. The method is implemented in the CEDRE code and completed by an algorithm for the reduction of the particles population to limit the cost of its statistical convergence. Applied to steady laminar premixed C2H4-air flames, it is confronted with some success to measurements of soot volume fraction, particle diameter and species molar fractions. The method is then applied combined with the Quasi-Steady State Approximation for gas chemistry to a swirled pressurized C2H4-air flame, similar to RQL configurations of aeroengine combustors, and confronted with some success to velocity, temperature, composition and soot volume fraction measurements
Khatami, Iman. "Free-field inlet / outlet noise identification on aircraft engines using microphones array." Thèse, Université de Sherbrooke, 2014. http://hdl.handle.net/11143/7581.
Résumé : La présente thèse étudie la discrimination du bruit d'entrée / de sortie des moteurs d'avion dans des tests statiques en champ libre en utilisant des antennes de microphones en champ lointain. Diverses techniques sont comparées pour ce problème, dont la formation de voie classique (CB), la méthode inverse régularisée (régularisation de Tikhonov), la formation de voies généralisée inverse (L1-GIB), Clean-PSF, Clean-SC et deux méthodes proposées qui s'appellent la méthode hybride et la méthode Clean-hybride. La méthode la formation de voie classique est désavantagée en raison de son besoin de nombreux microphones de mesure. De même, la méthode inverse est désavantagée en raison du besoin d'information a priori sur les sources. La régularisation Tikhonov classique fournit des améliorations dans. la stabilité de la solution; cependant elle reste désavantageuse en raison de son exigence d'imposer une pénalité plus forte pour des positions de source non détectées. Des sources cohérentes et incohérentes peuvent être résolues par la formation de voies généralisée inverse (L1-GIB). Cet algorithme peut identifier les sources multi- polaires aussi bien que les sources monopolaires. Cependant, l'identification de source par la formation de voies généralisée inverse prend beaucoup de temps et exige un ordinateur avec une capacité de mémoire élevée. La méthode hybride est une nouvelle méthode de régularisation qui implique l'utilisation d'un traitement par formation de voie a priori pour définir une norme discrète et dépendante des données pour la régularisation du problème inverse. En comparaison avec la formation de voie classique et la méthode inverse, l'approche hybride (régularisation par formation de voie) fournit des cartographies améliorées d'amplitudes de sources sans aucune complexité supplémentaire substantielle. Bien que la méthode hybride lève les limitations des méthodes classiques, l'application de cette méthode pour l'identification de sources de faible puissance en présence de sources de forte puissance n'est pas satisfaisante. On peut expliquer ceci par la plus grande pénalisation appliquée à la source plus faible dans la méthode hybride, qui aboutit à la sous-estimation de l'amplitude de cette source. Pour surmonter ce défaut, la méthode Clean-SC et la méthode Clean-hybrides proposée qui est une combinaison de la méthode hybride et de Clean-SC sont appliquées. Ces méthodes éliminent l'effet des sources fortes dans les cartographies de puissance de sources pour identifier les sources plus faibles. Les méthodes proposées qui représentent la contribution principale de cette thèse conduisent à des résultats fiables et ouvrent des nouvelles voies de recherche. L'étude théorique de toutes les approches est menée pour divers types de sources et de configurations microphoniques. Pour valider l'étude théorique, plusieurs expériences en laboratoire sont réalisées à Université de Sherbrooke. Les méthodes proposées ont été appliquées aux données de bruit mesurées d'une turbo-soufflante Pratt & Whitney Canada pour fournir une meilleure résolution spatiale des sources acoustique et une solution robuste avec un nombre limité des microphones de mesure comparé aux méthodes existantes.
Ben, Saad Seifallah. "Conception d'un algorithme de coordination hybride de groupes de robots sous-marins communicants. Application : acquisition optique systématique et détaillée des fonds marins." Thesis, Brest, 2016. http://www.theses.fr/2016BRES0052/document.
In the underwater environment, the needs of data acquisition have significantly increased over the last decades. As electromagnetic waves show poor propagation in sea water, acoustical sensing is generally preferred. However, the emergence of small and low cost autonomous underwater vehicles (AUV) allow for rethinking the underwater use of optical sensors as their small coverage can be significantly improved by using a fleet of coordinated underwater robots.This paper presents a strategy to coordinate the group of robots in order to systematically survey the seabed to detect small objects or singularities. The proposed hybrid coordination strategy is defined by two main modes. The first mode relies on a swarm algorithm to organize the team in geometrical formation. In the second mode, the robot formation is maintained using a hierarchical coordination. A finite state machine controls the high level hybrid strategy by defining the appropriate coordination mode according to the evolution of the mission. Before sea validation, the behavior and the performance of the hybrid coordination strategy are first assessed in simulation. The control of individual robots relies on visual servoing, implemented with the OpenCV library, and the simulation tool is based on Blender software.The dynamics of the robots has been implemented in a realistic way in Blender by using the Bullet solver and the hydrodynamic coeficcients estimated on the actual robot. First results of the hybrid coordination strategy applied on a fleet of 3 AUV’s, show execution of a video acquisition task by a group of autonomous robots controlled by vision and coordinated by a hybrid strategy
Cedola, Alessia. "Production de faisceaux de rayons-X submicroniques par guide d'onde en couches minces." Université Joseph Fourier (Grenoble ; 1971-2015), 1999. http://www.theses.fr/1999GRE10040.
Tribet, Hervé. "Aménagements des activités des formés au sein d'un dispositif hybride de formation et retombées sur leur activité professionnelle : une étude de cas dans le cadre de la formation de tuteurs de terrain de professeurs stagiaires." Thesis, Toulouse 2, 2018. http://www.theses.fr/2018TOU20102/document.
Face-to-face vocational training models, although still predominant, are increasingly being "shaken up" by other models using online teaching tools (Karsenti, Garry & Benziane, 2012). The combination of these models has led to the emergence of "hybrid" training systems (HTS), which alternate autonomous platform-based distance learning activities and classroom training activities (Jézégou, 2014). The literature review on the matter reveals that few studies question the nature of the design of HTS and the impact on the trainees’ and trainers’ activity involved.This thesis is part of a research program conducted in cultural anthropology whose central objective is the study of subject construction in professional training (Chaliès & Bertone, 2017). This transformative research explores the effects of developed scenarios of an HTS based on assumptions borrowed from a theory of adult education (Bertone & Chaliès, 2015), with the joint activity of novice cooperating teachers as being responsible for preservice teachers and a university supervisor.The results of the study shows that the structuring unique training activities deployed within the HTS has enabled novice cooperating teachers to gradually develop the capacity for meaning, analysis and simulated implementation of the pedagogical advisory activities. While this was the basis of the research hypothesis, the results underline that it was not possible to observe any effective learning at the end of the training. Nevertheless, this thesis opens up new technological perspectives in terms of the design of hybrid vocational training scheme
Ledoux, Xavier. "Formation et desexcitation des noyaux chauds dans les reactions induites par des faisceaux de protons (475 mev et 2 gev) et d'#3he (2 gev)." Caen, 1995. http://www.theses.fr/1995CAEN2016.
Tali, Fatiha. "Les apprentissages professionnels des enseignants : le cas d'une formation hybride d'enseignants du second degré se spécialisant pour scolariser des élèves en situation de handicap." Thesis, Toulouse 2, 2016. http://www.theses.fr/2016TOU20110.
This thesis, in a social cognitive approach, studies the professional learning of secondary education teachers specializing in disabled pupils. The goal is to show that under specializing learning teachers build professional knowledge in the social interaction whether on-site or on-line with their peers thanks to the hybrid system tools; especially thanks to an on-line log book. Our theoretical framework gathers professional learning theories. The social construction of learning takes into account the importance of the social and cultural environments, the individual’s place when building knowledge, as well as the interactions through different aspects. The professional knowledge can be used by the teacher and be seen as knowledge mentioned in the on-line log book, as the perceived knowledge through the evolution of the Professional Feeling of Efficiency level (SEPro in French), as well as the perceived knowledge in the teacher’s practice when adapting to class and outside the classroom. From a mixed methodology, this study presents the survey results performed following five teachers from the secondary education under a specializing learning (2CA-SH: Accreditation for specialized teachers for secondary school and higher levels) in a hybrid context at the ESPE of Toulouse (Teaching and Learning Graduate School). A comparison is done parallel to the SEPro level evolution with a group of teachers following the same on-site training (n= 24) and a group without training (n =58). The analysis of the empirical elements shows that the on-line and on-site interactions with peers let them build professional knowledge linked to adaptive professional behaviors and the pupils understanding. It also shows that knowledge becomes diversified during the learning year. The built knowledge is used in their SEPro, in their practice and in the elaboration of the on-line log book. The link between the professional knowledge nature and the learning process (social learning) allows to highlight the processes the teachers interacting on-site and on-line with peers prefer. It also allows to propose a social learning model in the context of a hybrid learning
Esta tesis, que se inscribe en una lógica socio cognitiva, estudia el aprendizaje profesional en el marco de una formación de profesores del grado Superior especializados en el tratamiento de alumnos con discapacidad. Su objetivo consiste en mostrar que el profesor en formación especializada construye conocimientos profesionales en la interacción social en presencial y a distancia con sus colegas gracias a herramientas del dispositivo híbrido, en especial a través de un diario de a bordo en línea. Nuestro marco teórico moviliza las teorías del aprendizaje profesional. La construcción social de los aprendizajes toma en cuenta la importancia del entorno social, cultural y el lugar del individuo en la construcción de los conocimientos, al mismo tiempo que moviliza las interacciones a través de diferentes modalidades. Los conocimientos profesionales pueden ser movilizados por el profesor e identificados como conocimientos listados en el diario de a bordo en línea, como conocimientos percibidos por la evolución del nivel de sentimiento de eficiencia profesional (SEPro) y como conocimientos constatados en las prácticas de adaptación en clase y fuera de clases. A partir de una metodología mixta, esta investigación presenta los resultados de una encuesta realizada con cinco profesores del grado Superior que siguieron una formación especializada (2CA-SH: Certificado de especialización complementaria del grado Superior) en un contexto híbrido en la ESPE (Escuela Superior de Profesorado y de la Educación) de Tolosa. Un comparativo se realizó en paralelo con la evolución del nivel de SEPro con un grupo de profesores que realizaron la misma formación presencial (n= 24) y un grupo sin formación (n =58). El análisis de los elementos empíricos muestra que las interacciones en línea y presenciales entre colegas permiten construir conocimientos profesionales relativos a los gestos de adaptación y al conocimiento de los alumnos y que dichos conocimientos se diversifican conforme pasa el año. Los conocimientos construidos son movilizados en su SEPro, en sus prácticas y en la elaboración del diario de a bordo. La interconexión de la naturaleza de los conocimientos profesionales y de los procesos de construcción de obras (aprendizaje social) permite actualizar los procesos privilegiados por los profesores que interactúan entre ellos en presencial y en línea y proponer un modelo de aprendizaje social en contexto de formación híbrida
Sow, Garmy. "Méthodes d'Accès Multiple à Répartition Spatiale pour Communications par Satellite." Phd thesis, Télécom ParisTech, 2006. http://pastel.archives-ouvertes.fr/pastel-00001876.
El, Metennani Faiza. "Analyse des approches d'apprentissage des étudiants universitaires, dans le contexte des formation hybrides." Thesis, CY Cergy Paris Université, 2020. http://www.theses.fr/2020CYUN1008.
A learner's behavior can be influenced by factors related to the environment, or by factors related to his own personal characteristics, Jézégou, (2014: 273). Our research work started from this research line. It is in this sense that we will try to understand from the perspective of the effects, the relationship between the hybrid device, the learning approaches and the personal characteristics of the students (gender and the feeling of personal effectiveness).Our research is experimental research, which makes it possible to determine the question of causality: if a student proceeds by such or such an approach, this is explained by factors related to the device, or else by factors related to his personal characteristicsWe were able to conduct our study in a university context in two different countries, Algeria and Cameroon. In the Algerian context, we were able to observe the progress of a hybrid course, supported by a teacher with 37 students. To better verify the notion of the effect of a hybrid device, we planned to experiment with this same hybrid course with the same teacher, but completely at distance (remotely), with another group of students (13 students). In the Cameroonian context, we observed the unfolding of a hybrid course, taught by a teacher, with 58 students from three promotions.We collected data on the variables, either by video recordings, or by retrieving data from the Moodle platform, or by questionnaire and interviews. The method of analysis is both a quantitative and a qualitative method.The results of our research reveal that the students proceeded much more by an in-depth approach. We concluded that the support of the teacher and the techno pedagogical environment have an effect on the learning approaches of the students.The results of our research also reveal that students who had a strong or weak sense of self-efficiency all proceeded through deep treatment approaches. So the feeling of self-efficiency does not have an effect on the choice of this or that learning approach. The results also indicate that there is no relationship between the biological characteristics of students (gender) and their learning approaches
Kimouche, Amina. "Vers de nouveaux matériaux hybrides basés sur le graphène épitaxié : contrôle de la formation de défauts et leur rôle dans l’intercalation." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENY027/document.
Epitaxial graphene grown on metal substrates is a promising platform for developing new hybrid systems, in which interface effects can be exploited to engineer novel properties. The insertion of foreign species between graphene and its substrate, referred to as “intercalation”, was shown very powerful in this respect. With the help of surface science tools, we have studied three graphene/metal systems, two of which are intercalated hybrid systems, and the other is a candidate for such a system: (i) graphene/Ir(111) intercalated with an ultrathin oxide, (ii) graphene/Ir(111) intercalated with cobalt (sub) atomic layers, and (iii) graphene on Re(0001). We found that some defects, especially wrinkles (linear delaminations of graphene from its substrate) and other curve graphene regions, play a crucial, yet unanticipated role in the intercalation process. We also found that the intercalation proceeds in a markedly different fashion under ultra-high vacuum and under atmospheric pressure. In the first system, oxygen-containing species were found to intercalate via the open end of wrinkles, to diffuse along then, and to form oxide nanoribbons along wrinkles accordingly. These ribbons modify the charge density of graphene, which also translates into substantial changes in the inelastic (Raman) optical response of graphene. In the second system, the efficiency of intercalation proved to be dependent on the graphene-metal interaction, which varies between differently oriented graphene domains on Ir(111). In this systems the entry sites for intercalated species could be identified, thanks to in operando observation of the process, as curved regions in graphene. Finally, graphene growth in a third system, graphene on Re(0001), was addressed in order to enable the future development of graphene/Re superconducting hybrids. In this system, we proposed two growth routes, one being a surface-confined process, on bulk single-crystal Re(0001), and the other being a temperature-induced segregation of carbon dissolved at high temperature in thin Re(0001) films on sapphire
Barros, Braga Adoniran Judson de. "Sondage de canal SIMO à l'intérieur des bâtiments et formation de faisceaux numérique utilisant des techniques de traitement de signal à haute résolution et corrélateurs cinq-ports." Paris, ENST, 2006. https://pastel.archives-ouvertes.fr/pastel-00002667.
The development of wideband mobile communication systems requires a better knowledge of the characteristics of the mobile channel as described by its power delay profile, directions of arrival and Doppler shifts of scatterers. A channel sounder can perform a multidimensional small-scale characterization of channels for stochastic modelling or communication system evaluation, such as allowable data rates. The aim of the present study is to assemble a number of instruments that are able to perform the sounding of SIMO propagation channels in indoor environments. Direction finding and beamforming systems are also implemented by using most of these tools, in particular, the Five-port circuit used as a homodyne demodulator of RF signals and high-resolution estimation techniques such as MUSIC. Five-port discriminators use a third redundant mixer to decrease the system dependency from the phase and amplitude unbalance of local oscillators. The directional angle resolved channel impulse response is jointly estimated in the angle and time delay domains by extending the MUSIC algorithm associated with the enhanced 2D-SS technique. The ray-tracing technique is implemented to compare channel parameters resolved deterministically to estimated parameters of an indoor propagation channel resolved by channel sounding. The performance of the beamforming system is tested by measuring the bit error rate for a different number of antenna array elements. We demonstrate the ability of the proposed system to perform spatial filtering and provide higher gain and smaller BER in the useful signal direction even in presence of a strong interference level
Ziani, Ghaouti. "Place des forums dans un dispositif de formation hybride appuyé sur la plateforme Moodle et médiatisation des savoirs : étude de cas en France et en Algérie." Electronic Thesis or Diss., Université de Lorraine, 2015. http://www.theses.fr/2015LORR0246.
The university context of hybrid formation, articulating group lessons and distance is apprehended here as a field of study on communication practices and media coverage of knowledge between learners. The question that guides our research is: How to explain the use or non-use communication tools of learning platforms of higher education? Are the activities of learners with platform communication tools (discussion forums) are knowledge activities? We have been situated in an interpretative epistemology, which oriente our attention on the discourses of interviewees (teachers and students) in two different cultural contexts, the University of Lorraine in France and universities of Tlemcen and Ouargla in Algeria. We examine media coverage of knowledge by convening the concepts of knowledge activities (Gérard, 2000) to analyze the discourse on activities that students are communication tools.At the end of our empirical study, we show that a hybrid device communication tools platform for learning open a range of possibilities but does not select for themselves the path that will monitoring for mediatisation of knowledges among learners. It responds to social and educational constraints facing uses. The mediatisation of knowledges is the product of interactions between all opened by the communication tools of learning platform opportunities, other communication practices, and social and educational constraints (role of the teacher, student engagement, ...) which characterize the context of inserting these communication devices. In this educational context, we found it almost impossible to imagine a process of appropriation discussion forums it is exclusively individual. It always passes through others and social relationships and even the process of knowledge construction
Ziani, Ghaouti. "Place des forums dans un dispositif de formation hybride appuyé sur la plateforme Moodle et médiatisation des savoirs : étude de cas en France et en Algérie." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0246.
The university context of hybrid formation, articulating group lessons and distance is apprehended here as a field of study on communication practices and media coverage of knowledge between learners. The question that guides our research is: How to explain the use or non-use communication tools of learning platforms of higher education? Are the activities of learners with platform communication tools (discussion forums) are knowledge activities? We have been situated in an interpretative epistemology, which oriente our attention on the discourses of interviewees (teachers and students) in two different cultural contexts, the University of Lorraine in France and universities of Tlemcen and Ouargla in Algeria. We examine media coverage of knowledge by convening the concepts of knowledge activities (Gérard, 2000) to analyze the discourse on activities that students are communication tools.At the end of our empirical study, we show that a hybrid device communication tools platform for learning open a range of possibilities but does not select for themselves the path that will monitoring for mediatisation of knowledges among learners. It responds to social and educational constraints facing uses. The mediatisation of knowledges is the product of interactions between all opened by the communication tools of learning platform opportunities, other communication practices, and social and educational constraints (role of the teacher, student engagement, ...) which characterize the context of inserting these communication devices. In this educational context, we found it almost impossible to imagine a process of appropriation discussion forums it is exclusively individual. It always passes through others and social relationships and even the process of knowledge construction
Mbambe, Bebey Danielle. "Design d'expériences transmédia pour l'engagement en formation (DEEXTEF)." Thesis, Paris, CNAM, 2018. http://www.theses.fr/2018CNAM1215/document.
We describe the phenomenon of engagement through co-constructed transmedia experiences with the beneficiaries in the context of adult education. We approach this ground on the assumption that a transmedia with experiential value makes it possible to increase the participation of subjects to consolidate the commitment in training. This hypothesis opens up the prospect of a transmedia type of mediation capable of integrating the objectives of scientific exploitation for the commitment and enhancement of participation and the attention that could be interesting for other corpuses. Based on an analysis framework focused on the beneficiaries of transactions, our survey highlighted different forms of hybrid transmedia engagement with specific characteristics. The complementarity of these transmedia has favoured various commitment regimes observed on an ad hoc basis for a long-term commitment
Barros, Braga Adoniran Judson de. "Sondage de canal SIMO à l'intérieur des bâtiments et formation de faisceaux numérique [sic] utilisant des techniques de traitement de signal à haute résolution et corrélateurs cinq-ports /." Paris : École nationale supérieure des télécommunications, 2007. http://catalogue.bnf.fr/ark:/12148/cb410244948.
Atlati, Samir. "Développement d'une nouvelle approche hybride pour la modélisation des échanges thermiques à l'interface outil-copeau : application à l'usinage de l'alliage d'aluminium aéronautique AA2024-T351." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0200/document.
This PhD. thesis is realised in the framework of an international cooperation between the University of Lorraine (France) and the University of Oujda (Morocco). The work done concerns the modelling of machining process by material removal. Two important aspects of machining have been investigated: the chip formation process and the heat exchange at the tool-chip interface. In the first part of the thesis, a FE modelling of the cutting process has been established. Chips segmentation have been particularly analysed using à new parameter (Segmentation Intensity Ratio) allowing the quantification of the phenomenon. A correlation has been established between the cutting force reduction and the chip segmentation intensity. The second part of the thesis has been devoted to the study of heat exchange at the tool-chip interface, among other phenomena that contribute to the tool wear. One important point of the study is the establishment of a hybrid identification procedure (analytical/numerical) to estimate the heat flux transmitted into the cutting tool, and identification of the heat partition coefficient at the contact interface for each cutting speed. With identified values of the heat partition coefficient obtained by varying the cutting speed, a heat exchange multi-branch law has been proposed and parameters of this law have been identified. This law corresponds firstly to the evolution of the heat partition coefficient as a function of the cutting speed. Thereafter, it was defined in term of the relative sliding velocity at the tool-chip contact interface, in order to implement it in a FE code. The user interface VUINTER of Abaqus/Explicit has been used to implement the proposed law, to fully control the mechanical and thermal contact. It is henceforth possible to implement with this user interface any thermomechanical contact (friction, heat partition coefficient, etc.). The implementation via the user subroutine VUINTER was validated first on adequate tests, then on machining. The obtained results for heat fluxes with this new procedure are in good agreement with experimental measurements for the tool-workmaterial couple considered: AA2024-T351/WC-Co
Abdallah, Ayman. "Contribution à l'étude d'une antenne adaptative et à la conception d'un démonstrateur." Limoges, 2007. http://www.theses.fr/2007LIMO4009.
Barroy, Willy. "L’hybridation du dispositif de formation d’Airbus Helicopters face aux technologies immersives : des enjeux d’apprentissage individuel et organisationnel." Thesis, Toulon, 2018. http://www.theses.fr/2018TOUL0002.
The purpose of this research is to better understand how training devices evolve, with the introduction of virtual reality technology, in industrialized training situations. This work I based on an immersion in the "training" department of Airbus Helicopters. The research-action approach allows us to observe and participate in the emergence of a technology of reality for pilot’s training. The tool is put in situation with customers as part of their training and several demonstrations are made to actors of different trades around the training. We identify hybrid configurations in the sense that training situations are both practical and at the same time theoretical in the language of the organization. Then we show that the implementation of these technologies requires to rethink a traditional rationalization. These elements allow to suggest an "approach by the hybridization of systems" gives the organization the ability to reconsider its own project (structured objects of information, organization chart, skills and trades of actors). It is a depth questioning of the learning organization that is possible, from the experience of subjects
Drouet, Julien. "Méthodes d’analyse électromagnétique spécifiques à la conception des antennes à résonateur BIE multi sources." Limoges, 2007. https://aurore.unilim.fr/theses/nxfile/default/d29cfcec-7bbb-48e9-a428-1749bae17636/blobholder:0/2007LIMO4039.pdf.
A feeding sources arrangement installed in an EBG resonator leads to profit at the same time from the array advantages (such as beamforming, nulling patterns, beam steering) and the resonator filtering attributes (spatial filtering, directivity increasing, steering). This report presents a set of steps that is adjusted to the EBG antennas development and design in particular multi sources EBG antennas. First, a spatial function computation is presented. This function results in the EBG resonator filtering attributes. Weighting the EBG resonator by a source radiation pattern allows the defined function to quickly evaluate the EBG performances. The second part focuses on the multi sources feeding problems. The goal of this part is to design and realize two prototypes. Then, the measures come to validate the antenna design. Aside from the resonating attributes of this kind of structure, the design steps are more tricky. Indeed, the EBG antenna intensifies the coupling phenomena between the radiating elements in the multi sources antennas. For this reason, a novel method overcoming the coupling complication was developed
Mabrouk, Kais. "Conception et réalisation d'un système de Télécommunications MIMO avec Formation Numérique de Faisceaux en réception ; Calibrage aveugle du Démodulateur triphasé Zéro-IF et comparaison au démodulateur classique à 2 voies I et Q." Phd thesis, Télécom ParisTech, 2008. http://tel.archives-ouvertes.fr/tel-00409794.
La première partie de ce travail est consacrée à une étude comparative entre les différents types de démodulateurs cinq-port et triphasés. Cette étude a permis de mettre en évidence l'aspect tridimensionnel des démodulateurs cinq-port et triphasés, de gagner 20dB en termes de réjection des produits d'intermodulation des signaux adjacents et de trouver une nouvelle méthode de calibrage aveugle du récepteur.
La seconde partie de la thèse se concentre sur le prototypage d'un système MIMO. Cette phase nous a permis d'exposer les difficultés de mise en place de ce genre de système et de souligner les nouvelles problématiques qui n'apparaissait pas auparavant dans les systèmes mono- transcepteur. Aussi, un algorithme de Formation de Faisceau a été développé dans cette partie. Ce FF numérique a permis non seulement d'accroître la capacité mais aussi la qualité de liaison en considérant le système MIMO comme N système SIMO en parallèle. Comparativement à la technique ZF(Zero Forcing), nous démontrons que le FF permet d'obtenir une meilleure qualité de signaux pour des faibles valeurs de rapport signal à bruit.
Mabrouk, Kaïs. "Conception et réalisation d'un système de télécommunications MIMO avec formation numérique de faisceaux en réception : calibrage aveugle du démodulateur triphasé zéro-IF et comparaison au démodulateur classique à 2 voies I et Q." Paris, ENST, 2008. http://tel.archives-ouvertes.fr/tel-00409794.
Within the framework of this research work, we have interested to a MIMO (Multiple Input Multiple Output) telecommunication system using the spatial multiplexing, Zero-IF receptors and the digital beamforming technique. The first part in this work is consecrated to a comparative study between two different kinds of Zero-IF demodulators: the classical IQ demodulator and the five-port and three-phase one. This study has allowed to highlight the three dimensional aspect of five-port and three-phase demodulators, to win up to 20dB in terms of rejection of inter-modulation product. Also this three dimensional aspect discovery help us to find a new blind calibration method. The second part of this thesis focuses on the prototyping of a MIMO system. This phase has allowed us to set the difficulties of the implementation of this systems kind and to highlight new problematics that don’t appear beforehand in mono-transceiver system. Moreover, a beamforming algorithm was developed in this part. This digital beamfoming has permit to increase the capacity as well as the quality of link when considering the MIMO system as N parallel SIMO systems. Compared to the ZF (Zero Forcing technique), we have proved that the beamforming permit the achievement a better signal quality for lower values of the signal to noise ratio