Le travail de thèse est consacré à l'étude des potentialités magnéto-optiques de couches minces élaborées par voie sol-gel organique-inorganique et dopées par de nanoparticules magnétiques dans le but de réaliser des composants à effet non réciproque en configuration guidée tel que l'isolateur optique. Le choix de la voie sol-gel se justifie par sa qualité de chimie douce et son aptitude à élaborer des guides de faible indice pour une épaisseur ajustable. L'intérêt porté aux nanoparticules magnétiques s'explique par l'effet magnéto-optique intéressant qu'elles présentent. La finalité de la thèse consiste à réaliser la conversion entre les modes TE-TM. Deux paramètres doivent donc être contrôlés finement pour obtenir un guide d'onde planaire ayant des effets magnéto-optiques intéressants : la biréfringence modale et la rotation Faraday. Les résultats obtenus montrent une très forte potentialité de la matrice sol-gel dopée. Il s'agit d'une rotation Faraday spécifique de 250 °/cm et une biréfringence modale de 10^(-4) ce qui permet de prévoir potentiellement un taux de conversion s'élevant 80 %. De plus, l'application d'un champ magnétique pendant la gélification des couches induit une forte diminution de la biréfringence ce qui permet de prévoir un accord de phase. Une conversion de mode totale est donc potentiellement réalisable. D'autre part, la courbe de la rotation Faraday présente un cycle d'hystérésis caractérisé par une rotation rémanente de 40 % de la valeur de la rotation à saturation, soit qr = 100 °/cm. L'existence d'une telle rotation sans aucun champ appliqué ouvre la voie à la réalisation de composants auto-polarisés.

L'objectif de la thèse est de développer des méthodologies d'étude et de caractérisation permettant de modéliser l'évolution du comportement de polymères thermodurcissables lors de leur mise en œuvre par le procédé de Moulage par Transfert de Résine (RTM).<br />La première partie donne une description globale de ce procédé et du savoir-faire actuel en matière de modélisation. Elle met en évidence la nécessité d'une modélisation précise des comportements cinétique et chimiorhéologique du polymère thermodurcissable utilisé.<br />Les travaux réalisés dans ces deux domaines sont ensuite présentés et illustrés par la caractérisation d'un système composite modèle dicyanate-ester / fibres de verre.<br />La deuxième partie concerne la modélisation des cinétiques de réticulation et a pour finalité de développer les méthodes de caractérisation par calorimétrie, ces dernières apparaissant comme une étape charnière entre les connaissances en chimie des thermodurcissables et la modélisation du procédé RTM.<br />Enfin, la dernière partie regroupe les travaux réalisés dans les domaines de la rhéologie et des écoulements. Ceux-ci concernent à la fois la caractérisation de la perméabilité des renforts, l'étude de la chimiorhéologie et le suivi in situ des propriétés rhéologiques au cours du procédé par spectrométrie diélectrique.

Les problèmes associés aux fluctuations de l'état de polarisation des signaux lumineux transitant dans la fibre optique limitent actuellement les débits en transmission. Les solutions basées sur un contrôle de la polarisation du signal utilisent principalement les propriétés de la fibre optique, des cristaux liquides ou du niobate de lithium (LiNbO3) pour les composants d'optique intégrée. Toutefois, la nature même de ces matériaux ne permet pas d'associer sur une même puce les fonctions optiques et électroniques. Pour relever le défit de la miniaturisation des dispositifs, l'utilisation des matériaux semiconducteurs s'impose. L'objectif de ce travail de thèse s'inscrit dans ce cadre : il s'agit d'étudier puis de concevoir un convertisseur de polarisation TE/TM intégré sur substrat semiconducteur III-V de type GaAs. Le composant se base sur les effets électro-optiques linéaires pour modifier l'état de polarisation du signal optique. Ainsi, en menant un étude sur les propriétés électro-optiques linéaires, nous avons montré que l'application de deux champs électriques croisés au niveau du guide optique permettait de modifier l'état de polarisation de la lumière avec une efficacité équivalente à celle des composants intégrés sur niobate de lithium. En modélisant la propagation des modes guidés à travers le composant, les paramètres structurels ont pu être déterminés de manière à répondre aux contraintes imposées par le mode de fonctionnement (biréfringence modale et pertes optiques TM minimales). Les guides de type "chargés enterrés" ont ensuite été réalisés en utilisant les techniques micro-photolithographiques. L'aspect relatif à la nature des contacts électriques a été ensuite développée puis les modulateurs ont été fabriqués. Les résultats issus de la caractérisation des composants sont très prometteurs et démontrent ainsi le potentiel des matériaux semiconducteurs.

<p>El presente análisis parte de un estudio contrastivo, el cual consta de una clasificación de los títulos literarios traducidos del castellano al sueco entre los años 1988 y 2007. Hemos clasificado los títulos según el grado de modificación semántica entre el título original y el título traducido. La parte cualitativa consta del análisis de algunos títulos del estudio contrastivo, con un enfoque particular en los títulos que han sido modificados, los efectos que las modificaciones conllevan, si se pueden motivar y por qué.</p><p>Parece haber un respeto profundo por el título original de una obra, ya que un 48% de los 208 títulos traducidos del estudio equivalen semánticamente a los títulos originales. Sin embargo, un 52% de los títulos ha sido modificado al ser traducido. Al analizar algunos casos de manera más profunda queda claro que más bien que ser cambios arbitrarios, las modificaciones lingüísticas pueden tener explicaciones sintácticas, estilísticas y/o culturales. El deseo de reconstruir significado connotativo y cierto nivel estilístico ha sido la guía en muchos casos. En efecto, una equivalencia formal, o traducir de manera más literal, no siempre es deseable, aunque sea una opción posible en la mayoría de los casos.</p>

<p>DAB (Digital Audio Broadcasting) is the radio digital system developed as an european standard by the ETSI, EN 300 400, based on the Eureka-147 group works, to improve the performance of the analogue radio systems (AM and FM). The system is based on the OFDM technology which allows DAB to exploit the spectrum frequencies in a better way with a higher quality of sound for mobile receivers specially. The main part of the OFDM system is based on the FFT algorithms to spread the data flow over different orthogonal carriers. The simulation has been developed in Simulink^TMand Matlab^TMand the layout designed follows faithfully the standard for the transmission system. The simulation can be reloaded by the user with the information presented in this thesis. Thus, this work can be continued to complete the DAB whole system simulation. The results obtained running this simulation show the main DAB system characteristics.</p>

Human intervention and natural phenomenon cause change in land use day by day. Availability of accurate land use information is essential for many applications like natural resource management, planning and monitoring programs. Landuse Change has become a central component in current strategies for managing natural resources and monitoring environmental change. Because of the rapid development in the field of land use mapping, there is an increase in studies of land use change worldwide. Providing an accurate assessment of the extent and health of the world’s forest, grassland and agricultural resources has become an important priority. By printed maps without any statistics or only statistics without any map can not solve this visualization problem. Because printed maps have not attracted as much attention as statistics among the people because of it is limited applications (Himiyama, 2002). Remotely sensed data like aerial photographs and satellite imageries are undoubtedly the most ideal data for extracting land use change information. Satellite images are the most economical way of getting data for different times. The multitude of existing software helps getting information from satellite image also in manipulating the information. The approach used in this study to classify satellite images and change detection based on Satellite images Landsat MSS (1972), Landsat TM (1989) and Landsat ETM (1999) for using supervised classification methods like maximum likelihood (MAXLIKE), MAHALCLASS and time series analysis of CROSSTAB. After performed these hard and soft classifiers the research showed the significant Landuse change in the study area of Chakoria Sundarban mangrove forest. Remote sensing is the modern tools for detecting change pattern and behaviours of coastal environment (Saifuzzaman, 2000). So, those tools are used in the research work for better change analysis of the study area. For analyzing, evaluation and mapping environmental change detection of different years remotely sensed data have been undertaken. The present research provides some suggestions and recommendations as per research findings in order to optimize the utility of coastal resources and to maintain the sustainability of the resources, coastal land use control and there by stabilizing the coastal vulnerable area of chakoria Sundarban.

DAB (Digital Audio Broadcasting) is the radio digital system developed as an european standard by the ETSI, EN 300 400, based on the Eureka-147 group works, to improve the performance of the analogue radio systems (AM and FM). The system is based on the OFDM technology which allows DAB to exploit the spectrum frequencies in a better way with a higher quality of sound for mobile receivers specially. The main part of the OFDM system is based on the FFT algorithms to spread the data flow over different orthogonal carriers. The simulation has been developed in Simulink&lt;sup&gt;TM&lt;/sup&gt;and Matlab&lt;sup&gt;TM&lt;/sup&gt;and the layout designed follows faithfully the standard for the transmission system. The simulation can be reloaded by the user with the information presented in this thesis. Thus, this work can be continued to complete the DAB whole system simulation. The results obtained running this simulation show the main DAB system characteristics.

Smart radial distribution grids will include advanced metering infrastructure (AMI) and significant distributed generators (DGs) connected close to loads. DGs in these radial distribution systems (RDS) introduce bidirectional power flows (BPFs) and contribute to fault current. These BPFs may cause unwanted tripping of existing overcurrent (OC) protection devices and result in permanent outages for a large number of customers. This thesis presents a protection approach that modified an existing overcurrent protection scheme to reduce the number of customers affected by faults in RDS with DGs. Further, a technique is presented that utilizes customers loading information from smart meters in AMI to improve the sensitivity of substation OC relays by adaptively changing the pickup settings. The modified protection approach involves predefining zones in RDS with DGs and installing directional OC relays and circuit breakers at the zonal boundaries. Zonal boundary relays determine faulted zones by sharing information on the direction of detected faults current using binary state signals over a communication medium. The technique to adapt the substation relay pickup settings uses the demand measurements from smart meters for two 12-hour intervals from the previous day to determine the maximum diversified demand at the relay?s location. The pickup settings of the substation relay for the two 12-hour intervals during the following day for the zone supplied by the substation are adaptively set based on the current that corresponds to the maximum diversified demand from the previous day. The techniques were validated through simulations in EMTP/PSCAD using an expanded IEEE 34 node radial test feeder that included DGs and a secondary distribution level. By decentralizing the control of the zonal boundary breakers, the single point of failure was eliminated in the modified protection approach. The cases studied showed that the modified protection approach allows for selective identification and isolation of the faulted zones. Also, the sensitivity of the substation OC relay was improved by at least 24% by using the pickup settings for the two 12-hour intervals from the smart meter demand measurements compared to the pickup settings computed using the conventional methodology based on the maximum loading of the zone.

The subject of this dissertation is to develop a rigorous transverse-mode integral equation formulation for analyzing TE/TM electromagnetic mode field solutions for dielectric waveguides. The main topics are composed of two related parts. The first part deals with scalar problems. In which we propose a transverse-mode integral-equation formulation for problems such as mode solutions of the ridged microwave waveguides. This same technique also applies to EM waves scattering off the facet of dielectric slab waveguides terminating in free space. For both problems we constructed a specifically chosen basis for the unknown tangential field functions, and we were able to reduce the kernel matrix size by more than one half without noticeable degradation of the field solutions. In the second part of the thesis, we apply a full-vector integral-equation formulation to analyze modal characteristics of the complex, two-dimensional, rectangular-like dielectric waveguide that is divisible into vertical slices of one-dimensional layered structures. The entire electromagnetic vector mode field solution is completely determined by the y-component electric and magnetic field functions on the interfaces between slices. These interfacial functions are governed by a system of vector-coupled transverse-mode integral equations (VCTMIE) whose kernels are made of orthonormal sets of both TE-to-y and TM-to-y modes from each slice. Finally, we show the numerical results to present the stable and quick convergence of this method as well as to improve the Gibb¡¦s phenomenon in the recreation of the transverse fields.

<p>Human intervention and natural phenomenon cause change in land use day by day. Availability of accurate land use information is essential for many applications like natural resource management, planning and monitoring programs. Landuse Change has become a central component in current strategies for managing natural resources and monitoring environmental change. Because of the rapid development in the field of land use mapping, there is an increase in studies of land use change worldwide. Providing an accurate assessment of the extent and health of the world’s forest, grassland and agricultural resources has become an important priority. By printed maps without any statistics or only statistics without any map can not solve this visualization problem. Because printed maps have not attracted as much attention as statistics among the people because of it is limited applications (Himiyama, 2002). Remotely sensed data like aerial photographs and satellite imageries are undoubtedly the most ideal data for extracting land use change information. Satellite images are the most economical way of getting data for different times. The multitude of existing software helps getting information from satellite image also in manipulating the information. The approach used in this study to classify satellite images and change detection based on Satellite images Landsat MSS (1972), Landsat TM (1989) and Landsat ETM (1999) for using supervised classification methods like maximum likelihood (MAXLIKE), MAHALCLASS and time series analysis of CROSSTAB. After performed these hard and soft classifiers the research showed the significant Landuse change in the study area of Chakoria Sundarban mangrove forest. Remote sensing is the modern tools for detecting change pattern and behaviours of coastal environment (Saifuzzaman, 2000). So, those tools are used in the research work for better change analysis of the study area. For analyzing, evaluation and mapping environmental change detection of different years remotely sensed data have been undertaken. The present research provides some suggestions and recommendations as per research findings in order to optimize the utility of coastal resources and to maintain the sustainability of the resources, coastal land use control and there by stabilizing the coastal vulnerable area of chakoria Sundarban.</p><p> </p>