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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Etude d'un projet innovant au sein de la supply chain : le cas de Schneider Electric / Study in an innovative project of supply chain management : the case of Schneider Electric

Wang, Yimiao 12 January 2012 (has links)
Ces dernière années l' « innovation » est au cœur de la stratégie de l'entreprise, elle est également attiré l'attention des chercheurs. En sciences de Gestion, les chercheurs étudient non seulement sur les innovations technologiques, mais aussi les innovations organisationnelles et managériales. Cette thèse étudie ces trois types d'innovation dans le cadre d'un projet innovant de la Supply Chain. Elle s'intéresse au processus de la diffusion d'innovation au sein de la Supply Chain, ainsi que l'appropriation par les acteurs des principaux éléments de ce processus. L'objectif est de vérifier les étapes de diffusion d'un projet innovant et d'analyser l'appropriation par les acteurs au niveau de la direction, de la division et de l'opérationnel d'un grand groupe industriel. Après avoir effectué l'examen des revues de littérature sur les théories d'innovation, de Supply Chain Management ainsi sur le Management du projet, un modèle conceptuel est établi. Par la suite, une recherche exploratoire qualitative est menée au sein du Groupe Schneider Electrics. Les données ont été collectées grâce à trois moyens : les entretiens individuels, l'observation et la participation au terrain et les documents internes de l'entreprise. Les données obtenues sont analysées par le technique de codage sur la base de grille thématique. Les résultats confirment que les innovations dans le Supply Chain Management incluent l'innovation organisationnelle et l'innovation managériale mais pourraient aussi contribuer à l'innovation technologique. Un projet innovant se diffuse en 5 étapes : i) Identification des problèmes, ii) Mise en relation problèmes / projet innovant, iii) Lancement du projet, iv) Déroulement du projet et v) Clôture du projet. Les analyses montrent également les acteurs s'approprient plus ou moins ; et différemment les principaux éléments de ce processus : la valeur du projet, les actions d'accompagnements, les outils spécifiques au projet ; etc. Dans cette thèse, le modèle de la diffusion d'un projet innovant est validé, les contributions et les perspectives sont ainsi proposées à la fin. / Recently, "innovation" has become the core strategy of the enterprises; it also attracted attentions by researchers. In Management Science, The research of innovation is not only confined to technological innovations but also including organizational and managerial innovation. This thesis examines three types of innovations within a framework of a supply chain, which includes innovation project, the process of diffusion of innovation concerning the supply chain, and the ownership of the actors on the main elements in the process. The research objective of this thesis is to verify the steps of diffusion to an innovative project and analyze the absorbing level of the actors within an innovation project, with the actors including the top management level, the division level and operation level in a big industrial group. A conceptual model has been established on the basis of literature review on the theories of innovation, supply chain management and project management. Subsequently, an exploratory qualitative study is conducted in Schneider Electric. The data was collected through three approaches: individual interviews, field survey and internal documentations. Then, the quantitative content analysis including the coding technique is used to deal with the data obtained. The results provide that the supply chain management innovations is not only including organizational innovation and managerial innovation, but may also contribute to technological innovation. The diffusion of an innovative project involves five steps: i) Identification of problems, ii) Matching problems / innovative project, iii) Launching of the project, iv) Execution of the project, and v) Closing of the project. The analysis also shows different absorbing level from the actors on the mains elements of this process. In this thesis, the model of diffusion of innovation project has been validated; the contributions and perspectives have been thus proposed.
62

FDTD Simulation Techniques for Simulation of Very Large 2D and 3D Domains Applied to Radar Propagation over the Ocean

January 2018 (has links)
abstract: A domain decomposition method for analyzing very large FDTD domains, hundreds of thousands of wavelengths long, is demonstrated by application to the problem of radar scattering in the maritime environment. Success depends on the elimination of artificial scattering from the “sky” boundary and is ensured by an ultra-high-performance absorbing termination which eliminates this reflection at angles of incidence as shallow as 0.03 degrees off grazing. The two-dimensional (2D) problem is used to detail the features of the method. The results are cross-validated by comparison to a parabolic equation (PE) method and surface integral equation method on a 1.7km sea surface problem, and to a PE method on propagation through an inhomogeneous atmosphere in a 4km-long space, both at X-band. Additional comparisons are made against boundary integral equation and PE methods from the literature in a 3.6km space containing an inhomogeneous atmosphere above a flat sea at S-band. The applicability of the method to the three-dimensional (3D) problem is shown via comparison of a 2D solution to the 3D solution of a corridor of sea. As a technical proof of the scalability of the problem with computational power, a 5m-wide, 2m-tall, 1050m-long 3D corridor containing 321.8 billion FDTD cells has been simulated at X-band. A plane wave spectrum analysis of the (X-band) scattered fields produced by a 5m-wide, 225m-long realistic 3D sea surface, and the 2D analog surface obtained by extruding a 2D sea along the width of the corridor, reveals the existence of out-of-plane 3D phenomena missed by the traditional 2D analysis. The realistic sea introduces random strong flashes and nulls in addition to a significant amount of cross-polarized field. Spatial integration using a dispersion-corrected Green function is used to reconstruct the scattered fields outside of the computational FDTD space which would impinge on a 3D target at the end of the corridor. The proposed final approach is a hybrid method where 2D FDTD carries the signal for the first tens of kilometers and the last kilometer is analyzed in 3D. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2018
63

Využití sluneční energie pro chlazení a klimatizaci / Using Solar Energy for Refrigeration and Air Conditioning

Chládek, Petr January 2010 (has links)
This thesis is dealing with the usage of solar energy for cooling and air-conditioning. Notification of the quantity of solar power which incidents to the Earth, types of solar power collector and discribes systems which are applicable for cooling and air-conditioning. Next part deal with calculation and proposal of combined system for warming-up domestic hot water, heating a bit more and cooling. In the last part I solve the capital expenditure and system´s economic return.
64

Snižování hluku počítačů obkládáním stěn zvukoizolačními materiály a regulací otáček ventilátorů / Noise control of computers-application of optimal sound isolation layers and fun rotation speed

Kunovský, Martin January 2011 (has links)
This thesis deals with the distribution of noise in the computer case and radiation into the neighborhood. Influence of geometrical shape and size of the computer case on radiated noise from the computer was investigated as well as effect of placement of the fan. Reducing noise by using sound absorbing material into computer case and result of the suitable position of the computer in the working environment were also tested. Simulation of the noise diffusion and effectivity of anti-noise equipment was executed in Ansys FEM program.
65

Two-photon Cross Section Enhancement of Photochromic Compounds for Use in 3D Optical Data Storage

Luchita, Gheorghe 01 January 2011 (has links)
Rewritable photochrome-based 3D optical data storage requires photochromic molecules with high two-photon absorption (2PA) cross sections. Currently, the low value of two-photon absorption cross sections of existing photochromes makes them unsuitable for practical application in 3D data storage. Worldwide attempts to increase the cross section of photochromic molecules by altering the chemical structure have yielded poor results. In this work, two ways to increase the two-photon absorption cross sections of photochromes were investigated. In the first method, partial success demonstrated by extending the conjugation of a photochromic molecule, a high two-photon absorption cross section of the closed form isomer and high photoconversion to the closed form were realized. At the same time, a decrease in photoswitching quantum yield and low photoconversion to open form was observed. A discussion is provided to explain the results, suggesting that the proposed method of extending the conjugation may not solve the problem. For this reason a new method for effective two-photon absorption cross section enhancement of photochromes was proposed. As a proof of principle, a new two-photon absorbing dye with a hydrogen bonding moiety was synthesized and used for the formation of supramolecular structures with a photochromic compound. Theoretical reasoning and experimental demonstration of energy transfer from the dye to the photochrome under one and two-photon excitation confirmed the practical value of the method. The effects of a 2PA dye on the photochromic properties of a diarylethene were investigated using a model compound to simplify data analysis. Formation of supramolecular structures was revealed using ¹H NMR spectroscopic methods. The model compound, having the same hydrogen bonding moiety as 2PA dye, has been demonstrated to bind with photochrome molecules at very low concentrations. Photochromic properties of 2,3-bis(2,4,5-trimethyl-3-thienyl)maleimide, including conversions at the photostationary state, extinction coefficients, photoisomerization reaction rates and quantum yields, were shown to be affected by hydrogen bonding with the model compound - 2,6-bis-(acetamido)pyridine. The extent of this change was determined and discussed, demonstrating a balanced supramolecular strategy to modulate photochemical and photophysical properties of this important class of photochromic material.
66

Simulation of the Optical Loop Mirror in Ultrafast Fiber Lasers

Zang, Yimin 29 May 2018 (has links)
No description available.
67

Validation of a CAA Code for a Case of Vortical Gust-Stator Interaction

Durand, Christopher January 2016 (has links)
No description available.
68

Attenuation of the higher-order cross-sectional modes in a duct with a thin porous layer

Horoshenkov, Kirill V., Yin, Y. January 2005 (has links)
No / A numerical method for sound propagation of higher-order cross-sectional modes in a duct of arbitrary cross-section and boundary conditions with nonzero, complex acoustic admittance has been considered. This method assumes that the cross-section of the duct is uniform and that the duct is of a considerable length so that the longitudinal modes can be neglected. The problem is reduced to a two-dimensional (2D) finite element (FE) solution, from which a set of cross-sectional eigen-values and eigen-functions are determined. This result is used to obtain the modal frequencies, velocities and the attenuation coefficients. The 2D FE solution is then extended to three-dimensional via the normal mode decomposition technique. The numerical solution is validated against experimental data for sound propagation in a pipe with inner walls partially covered by coarse sand or granulated rubber. The values of the eigen-frequencies calculated from the proposed numerical model are validated against those predicted by the standard analytical solution for both a circular and rectangular pipe with rigid walls. It is shown that the considered numerical method is useful for predicting the sound pressure distribution, attenuation, and eigen-frequencies in a duct with acoustically nonrigid boundary conditions. The purpose of this work is to pave the way for the development of an efficient inverse problem solution for the remote characterization of the acoustic boundary conditions in natural and artificial waveguides.
69

Développement d'un dispositif intégré de photodétection de grande sensibilité avec discrimination spectrale pour les laboratoires sur puce

Courcier, Thierry January 2014 (has links)
Résumé : Ce travail de thèse a pour but de développer un dispositif intégré de photodétection pour des applications biomédicales nécessitant une grande sensibilité de détection et une discrimination spectrale (sélectivité). Ce dispositif peut être appliqué, par exemple, à la mesure simultanée de plusieurs marqueurs fluorescents dans les laboratoires sur puce mettant en œuvre de très faibles volumes de réactifs (inférieurs au microlitre). Le travail de thèse se focalise sur la conception, la réalisation et le test de ce dispositif intégré de photodétection. Ce travail se décline selon deux axes principaux : d’une part, la conception d’un photodétecteur CMOS avec préamplificateurs intégrés, et d’autre part la conception, la réalisation et la caractérisation de filtres optiques intégrés performants pour la détection de fluorescence. Le dispositif de détection conçu implémente un photodétecteur à quatre jonctions enterrées (Buried Quad Junction photodetector – BQJ) et un étage de préamplification de charge pour le traitement simultané des quatre sorties de ce photodétecteur. L’ensemble a été fabriqué en technologie Haut-Voltage CMOS Teledyne-DALSA 0,8μm. Son fonctionnement a été démontré et ses performances, notamment en termes de bruit et de sensibilité, ont été caractérisées. En parallèle, des filtres optiques coupe-bande ont été développés à l’aide d’un procédé compatible avec la technologie CMOS utilisée pour le photodétecteur. Ainsi, le dépôt de ces filtres sur le photodétecteur pourra être intégré dans le process de fabrication industriel. Les filtres interférentiels développés sont fabriqués en alternant des dépôts de couches minces de nitrure et d’oxyde de silicium par PECVD. La mesure des indices optiques de ces matériaux a été utilisée pour optimiser ces filtres à partir de simulations. Les filtres déposés sur lame de verre ou sur le photodétecteur BQJ ont été caractérisés. Des méthodes de traitement des signaux spécifiques pour le BQJ sont également proposées pour améliorer la sensibilité et/ou la sélectivité de détection. Leurs performances ont été évaluées. Enfin, des mesures de fluorescence avec le système de photodétection conçu ont été réalisées sur des mélanges de nanocristaux fluorescents (quantum dots) ou de fluorophores organiques. Ces résultats préliminaires permettent de valider le fonctionnement applicatif du système de photodétection développé. // Abstract : This thesis aims to develop an integrated photosensor device for biomedical applications requiring high detection sensitivity and spectral discrimination (selectivity). For example, this system can be applied to mesure simultaneous emissions of several fluorescent labels in lab-on-a-chip implementing very small volumes of reagents (less than one microliter). The thesis focuses on the design, implementation and testing of this integrated photodetector device. The work is divided in two main parts: first, the design of a CMOS photodetector with integrated preamplifiers, and secondly the design, realization and characterization of integrated optical filters for fluorescence detection. The detection device implements a Buried Quad Junction photodetector (BQJ) and charge sensitive preamplifiers for the simultaneous treatment of its four outputs. The chip was made in 0.8μm High Voltage CMOS technology from Teledyne-DALSA. Its operation has been demonstrated and its performances, especially in terms of noise and sensitivity, have been characterized. In parallel, optical notch filters have been developed using a process compatible with the CMOS technology used for the photodetector fabrication. Thus, deposition of these filters on the photodetector can be integrated during industrial process. Developed interference filters are made by alternating deposition of thin layers of nitride and silicon oxide by PECVD. Measurements of refractive index of these materials were used to optimize these filters through simulations. The filters implemented on a glass cover or on the BQJ photodetector were characterized. Signal processing methods specific to BQJ are also proposed to improve the detection’s sensitivity and/or selectivity. Their performances were evaluated. Finally, fluorescence measurements with the designed photodetection device were performed on mixtures of fluorescent nanocrystals (quantum dots) or of organic fluorophores. These preliminary results validate the performances in terms of photodetection of the designed integrated photodetection device.
70

Car seat design and human-body modelling for rear impact whiplash mitigation

Himmetoglu, Selcuk January 2008 (has links)
Whiplash is a neck injury caused by the sudden differential movement between the head and torso. Whiplash injuries are most commonly reported as a consequence of rear impacts in car accidents. They are regarded as minor injuries, but can still lead to long-term disablement and discomfort in the neck. Whiplash injuries can be mitigated by better car seat designs. For this purpose, head restraint geometry must be improved first, and then the dynamic performance of the whole seat must be assessed at all crash seventies. A biofidelic human-body model is a key requirement in designing whiplash mitigating car seats. This thesis presents the development of a 50th percentile male multi-body human model and several energy absorbing car seat designs. The human-body model is specifically designed for rear impact and validated using the responses of seven volunteers from Japanese Automobile Research Institute (JARI) sled tests, which were performed at an impact speed of 8 kph with a rigid seat and without head restraint and seat belt. A generic multi-body car seat model is also developed to implement various seatback and recliner properties, anti-whiplash devices (A WDs) and head restraints. Using the same driving posture and the rigid seat in the JARI sled tests as the basic configuration, several anti-whiplash seats are designed to allow different types of motion for the seatback and seat-pan. The major findings of this research are: -The human-body model simulates the effects of muscle contraction and its overall response is superior in comparison to the currently used models and dummies. -A criterion called the S-shape index (SSI) is developed based on the intervertebral angles of the upper and lower cervical spine. -The car seat design concepts are able to control and use crash energy effectively with the aid of anti-whiplash devices for a wide range of crash seventies. -In order to reduce whiplash injury risk, this study advocates energy absorbing car seats which can also provide head restraint contact as early as possible.

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