This thesis will examine the practice of relational aesthetics as it involves the viewer, as well as the way in which it plays out within and outside of the institutional setting of the museum. I will focus primarily on two unique projects: that of The Machine Project Field Guide at Los Angeles County Museum of Art on November 15, 2008, produced by Machine Project, a social project operated out of a storefront gallery in Echo Park; and David Michalek's Slow Dancing at the Lincoln Center Festival in New York City, July 12-29 2007.

Du fait de nombreuses avancées technologiques et scientifiques, l'ensemble du réseau de télécommunications a évolué vers une complexité croissante intégrant désormais des débits très importants. Grâce aux larges bandes passantes offertes par les bandes de fréquences millimétriques, les prochaines générations visent à permettre l'augmentation du nombre de services multimédias et de partage de contenus en haute définition. Cette évolution pose la problématique de concevoir des systèmes sans-fils capables de fonctionner en haute fréquence avec des rendements et coûts acceptables, ainsi qu'un encombrement minimum. Ce travail se situe dans le cadre du développement de circuits passifs, de types filtres, coupleurs et guides d'ondes qui répondent à ces défis. Nous avons développé une technique de miniaturisation pour des dispositifs en technologie imprimée, dans un premier temps dédiée aux fréquences inférieures à 20 GHz. Celle-ci repose sur la notion d'onde lente, définie comme la capacité d’une structure à ralentir la propagation des ondes la traversant. Une analyse théorique ainsi que des méthodes de conception ont été développées, puis validées par des mesures. Dans un second temps, nous avons proposé deux technologies distinctes permettant l'intégration de guides d'ondes performants en bande millimétrique en collaboration avec deux laboratoires partenaires. Une étude théorique, la conception de motifs de test et les résultats de mesure sont présentés. Ces travaux constituent une base pour la réalisation ultérieure en bande millimétrique de topologies miniaturisées grâce aux ondes lentes. / The last decades have seen the evolution of communication networks towardgreater complexity and efficiency, being now able to carry significant data rates. This evolution is the result of both scientific and technological breakthroughs. Thanks to the wide bandwidths available at millimeter-wave frequencies, the future generations will be able to supply for the the increasing demand in multimedia services, especially high-definition videos. The design of wireless systems which operate at high frequencies with acceptable efficiency, costs, and minimum size thus constitute a decisive challenge. In this context, this work focuses on the development of passive circuits such as filters, couplers and waveguides which address these issues. We developed a miniaturization technique for printed circuits technology, which in a first step is dedicated to frequencies below 20 GHz. This technique is based on a slow-wave concept, defined as the property of any structure which impose lower velocities to the electromagnetic waves. A theoretical analysis, as well as design methods were established and confirmed by measurements. Secondly, we proposed two distinct technological solutions for the integration of efficient waveguides at millimeter-wave frequencies. This work was achieved in collaboration with two other laboratories. A theoretical study, design of test features and measurementswere performed. These results intend to constitute a basis for the future realization of miniaturized slow-wave circuits at millimeter-wave frequency bands.

Nous proposons des liaisons optiques en Silicium à faible coût utilisant des longueurs d'onde de propagation de 650 à 850 nm. La création de circuits intégrés optoélectroniques à grande échelle et de bus de données optiques au sein même des circuits intégrés, utilisant des composés Silicium CMOS, ont été envisagées présentant une voie prometteuse [1] - [3]. Dans les dernières tentatives de réalisation de systèmes optoélectroniques en CMOS, les technologies était principalement orientée sur l'utilisation des longueurs d'onde à 1550 nm [4] - [6], principalement en raison de la facilité de conception et de fabrication des guides d'ondes dans ce régime de longueur d'onde. Cependant, aucune source optique rapide efficace et aucun photo-détecteur Si ne sont disponibles à cette longueur d'onde de 1550 nm. Aujourd'hui, les solutions pour surmonter le problème sont principalement axées sur l'intégration de sources optiques basées sur des éléments du groupe IIIV reportés sur Silicium par liaison moléculaire [7a] - [7b].Si la source optique, le détecteur, les guides d'ondes et les capteurs pouvaient être réalisés sur la même puce CMOS Silicium, par exemple à une longueur d'onde de 750 nm, divers systèmes micro-photoniques sur puces, légers et miniaturisés, pourraient être conçus et réalisés. Alors que les sources optiques au Silicium ne sont peut-être pas encore au niveau de performance requis pour les communications à très haut débit, les systèmes optoélectroniques "tout-Silicium" à faible coût restent encore un excellent point de départ. Ces sources pourraient également conduire à un nouveau champ qui pourrait s'appeler «microsystèmes photoniques Si» ouvrant la voie à de nouvelles applications et produits notamment pour l'optique médicale, biomédicale, les interconnexions optiques et la biophotonique. Ces systèmes ne nécessitent de bande passante à très haute fréquence pour émettre, et les puissances d'émission de nos diodes électroluminescentes (LED) à avalanche peuvent être suffisantes pour assurer le fonctionnement de tels systèmes. Ce travail de thèse de doctorat traite donc des liaisons optiques SiGe / Si à faible coût en utilisant des dispositifs Photonique-Microondes tels que une source à Diode Electro-Luminescente (DEL) à avalanche en Silicium (SiAvLED) et Silicium-Germanium intégrée en technologie bipolaire, des guides d'ondes optiques en Nitrure de Silicium et en Oxyde de Silicium, des phototransistors bipolaires à hétérojonction (HPT) SiGe. Ce travail se concentre sur l'intégration combinée de sources optiques à l'échelle micrométrique, de guides d'ondes optiques et de détecteurs sur une même puce pour former une liaison de communication complète pour diverses applications iv impliquant des liaisons de courte longueur d'onde (750 nm à 950 nm). Les progrès fournis par ce travail par rapport aux travaux antérieurs pourraient être synthétisés comme suit:• La source optique, le guide d'ondes et le détecteur ont tous été intégrés et alignés sur la même puce, dans une technologie industrielle RF bipolaire SiGe 0,35μm, pour former une liaison optique ou optique micro-onde complète sur puce à la longueur d'onde de 750 nm.• Une série de liaisons de communication optique de deuxième génération de 50μm de longueur, utilisant des longueurs d'onde de propagation de 650 à 850 nm, a été conçue et réalisée en technologie SiGe bipolaire également. Des sources optiques, des guides d'ondes et des détecteurs de dimensions micrométriques ont tous été intégrés sur la même puce pour former une communication complète sur les liaisons micro-optiques. Des LED Si à base d'avalanche (Si Av LED), des contacts Schottky, des stratégies de densification TEOS, des guides d'ondes à base de Nitrure de Silicium et des technologies de détection bipolaire SiGe de pointe ont été utilisées comme stratégies de conception clés.• Le logiciel de simulation R-soft (Beam Prop) a été utilisé comme outil de simulation / We propose a low cost full-silicon optical links utilizing 650 – 850 nm propagation wavelengths. The creation of large-scale opto-electronic integrated circuits and optical data “highways” inCMOS integrated circuitry, utilizing Si CMOS compounds, have been envisioned and hold much promise [1] - [3] The latest attempts for realizing optoelectronic systems in CMOS technology have until now mainly been focused on utilizing wavelengths at 1550 nm [4] - [6], mainly because of the ease of design and fabrication of waveguides in this wavelength regime. However, no effective high-speed optical sources and Si detectors are available at this 1550nmwavelength. Today solutions to overcome the problem are mostly focused on the integration of group III-V elements based optical sources on Silicon through molecular bonding [7a] – [7b]. If optical sources, detectors, waveguides, and sensors could be realized on the same Si CMOS chip at, say, 750 nm wavelength, various low power consuming, light and miniature on-chip-based micro-photonic systems can be designed and realized. While Silicon optical sources may not yet be at the required performance level for very-high speed communications, the low cost “all silicon”opto-electronic systems still remain a great grail. These sources could lead as well to new field that could be appropriately named “Si photonic microsystems” opening the route to new sensing applications and products especially for the medical, biomedical optics, optical interconnect and bio-photonics field. These systems also do not require ultrahigh frequency bandwidths to transmit, and the emission powers of our avalanche Si light-emitting diodes(LEDs) may be sufficient to sustain the operation of such systems. This PhD thus deals with low cost SiGe/Si optical links using Microwave-Photonics devices such as, Bipolar integrated SiAvLED, Silicon Nitride and Silicon Oxide optical waveguides, SiGeHPTs, Si and SiGe/Si LEDs. It focuses on the combined integration of micron-scale optical sources, optical waveguides and detectors on the same chip to form a complete communication link for various applications involving short wavelength links (750nm to 950nm). The progress provided by this PhD to previous works could be synthesized as below:• Optical source, waveguide and the detector were all integrated and aligned on the same chip, in an industrial based technology, to form complete on-chip micro-optical links at750nm wavelength, with a SiGe radio frequency (RF) 0.35µm bipolar process.• A series of second generation of on-chip optical communication links of 50µm length, utilizing 650 – 850 nm propagation wavelengths, have been designed and realized inSiGe. Micron dimensioned optical sources, waveguides and detectors were all integrated ion the same chip to form a complete communication on-chip micro-optical links. Avalanche based Si LEDs (Si Av LEDs), Schottky contacting, TEOS densification strategies, Silicon-Nitride based waveguides, and state of the art SiGe bipolar detector technologies were used as key design strategies.• R-soft simulation software (Beam Prop) was used as a mathematical capable simulation tool to model various Silicon-Nitride optical waveguide structures, before the designing, the fabrication, characterization and testing of the device. Various device structures were modeled, simulation iterations were performed on several optical waveguide designed structures before the device design, and the devices were tested experimentally.• Best performances of the designed on-chip optical links show a conversion loss as low as30dB from source to detector with up to 500MHz in cut off frequency. The good alignment and the good efficiency of each device are then clearly achieved. Higher frequency performances are also envisaged from preliminary measurements

L’objectif de ces travaux est le développement en technologie intégrée standard d’une topologiede ligne de propagation optimisée en termes de pertes, d’encombrement et de facteur de qualitéaux fréquences millimétriques. Cette topologie nommée S-CPW (Shielded CoPlanarWaveguide) utilise le phénomène d’ondes lentes afin de miniaturiser longitudinalement la ligned’un facteur compris entre 1,3 et 3,2 par rapport à des topologies classiques. Disposantégalement de faibles pertes, les lignes développées présentent un facteur de qualité élevé parfoissupérieur à 40, à 60 GHz. A partir de l’étude du champ électromagnétique dans la structure, unmodèle électrique a été développé. C’est le premier modèle dans la littérature prenant en compteles pertes dans ce type de guide d’onde. Plusieurs dispositifs passifs intégrés réalisés avec deslignes S-CPW dans différentes technologies CMOS ont été caractérisés jusqu’à 110GHz. Lacompacité et les faibles pertes d’insertion obtenues pour la mesure de filtres à stubs et dediviseurs de puissance permettent de réussir l’intégration de circuits passifs compacts entechnologie microélectronique CMOS standard aux fréquences millimétriques. / This work focuses on high-performance S-CPW (Shielded CoPlanar Waveguide) transmissionlines in classical CMOS integrated technologies for the millimeter-wave frequency band.Thanks to an important slow-wave phenomenon, the physical length of S-CPW decreases by afactor from 1.3 to 3.2 compared with classical transmission lines. Presenting also lowattenuation loss, the developed transmission lines show very high quality factor (higher than 40at 60 GHz). The precise study of the electromagnetism field leads to an electrical model forS-CPWs. This is the first model that takes the losses in this topology into account. Then, somebasic passive circuits designed with S-CPWs and characterized up to 110 GHz are presented invarious CMOS technologies. The low insertion losses and relative low surfaces of a powerdivider and a passband filter show the great interest of S-CPW to integrate compact passivecircuits in classical CMOS technologies at millimeter-wave frequencies.

Submitted by Lara Oliveira (lara@ufersa.edu.br) on 2017-06-29T16:57:37Z No. of bitstreams: 1 FranciscoMC_DISSERT.pdf: 3890460 bytes, checksum: d32d157669d00a07d57f91a8d177dec3 (MD5) / Rejected by Vanessa Christiane (referencia@ufersa.edu.br), reason: Corrigir referência. on 2017-07-03T12:21:11Z (GMT) / Submitted by Lara Oliveira (lara@ufersa.edu.br) on 2017-07-04T15:07:33Z No. of bitstreams: 1 FranciscoMC_DISSERT.pdf: 3890460 bytes, checksum: d32d157669d00a07d57f91a8d177dec3 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-07-04T16:56:15Z (GMT) No. of bitstreams: 1 FranciscoMC_DISSERT.pdf: 3890460 bytes, checksum: d32d157669d00a07d57f91a8d177dec3 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-07-04T16:58:56Z (GMT) No. of bitstreams: 1 FranciscoMC_DISSERT.pdf: 3890460 bytes, checksum: d32d157669d00a07d57f91a8d177dec3 (MD5) / Made available in DSpace on 2017-07-04T16:59:07Z (GMT). No. of bitstreams: 1 FranciscoMC_DISSERT.pdf: 3890460 bytes, checksum: d32d157669d00a07d57f91a8d177dec3 (MD5) Previous issue date: 2017-03-10 / The model of education in the last decades has undergone considerable changes from a didactic point of view. With the advancement of technology, the speed of obtaining information increases and the use of tools that allow the dynamic visualization of content becomes a strong ally to the teaching-learning process. This work deals with the creation of an interactive tool to visualize the propagation of traveling waves in an electric power system, with the possibility of insertion of data by the user, in order to facilitate the consolidation of knowledge. The model was created from the GUIDE of Matlab R, which has a graphical interface with the possibility of inserting data into a single screen with action buttons, which when clicked performs actions like calculate and display the animated graphic. It is important to highlight that the creation of the program, besides facilitating the student's understanding, due to the animation, also allow a better familiarization with computer simulation software, and with the parameters used in the transient analysis in transmission lines / O modelo de educação nas últimas décadas vem sofrendo alterações consideráveis do ponto de vista didático. Com o avanço da tecnologia, a velocidade da obtenção de informações aumenta e a utilização de ferramentas que possibilitem a visualização dinâmica do conteúdo se faz um forte aliado ao processo ensino-aprendizado. Esse trabalho aborda a criação de uma ferramenta interativa para a visualização da propagação de ondas viajantes em um sistema elétrico de potência, com a possibilidade de inserção de dados por parte do usuário, afi m de facilitar a consolidação do conhecimento. O modelo foi criado a partir do GUIDE do Matlab R, que possui uma interface gráfica com a possibilidade de inserção de dados em uma única tela com botões de ação, que ao serem clicados realizam ações como calcular e mostrar o gráfi co animado. É importante destacar que a criação do programa além de facilitar a compreensão por parte do aluno, devido à animação, também possibilita uma maior familiarização com softwares de simulação computacional, e com os parâmetros utilizados na análise do transitório em linhas de transmissão / 2017-06-28

Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-12-18T20:32:46Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) eulalia_aparecida_silva.pdf: 2432219 bytes, checksum: e8c925e3e5ce27f2aa2cd5015580bd28 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-01-03T17:15:50Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) eulalia_aparecida_silva.pdf: 2432219 bytes, checksum: e8c925e3e5ce27f2aa2cd5015580bd28 (MD5) / Made available in DSpace on 2018-01-03T17:15:50Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) eulalia_aparecida_silva.pdf: 2432219 bytes, checksum: e8c925e3e5ce27f2aa2cd5015580bd28 (MD5) Previous issue date: 2017 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O objetivo do trabalho foi avaliar a efici?ncia da classifica??o da capacidade produtiva de povoamentos florestais de eucalipto (Eucalyptus ssp.) por meio de rede neural artificial (RNA). Os dados utilizados foram provenientes de invent?rios florestais cont?nuos conduzidos em povoamentos de clones de Eucalyptus ssp. localizados no estado de Minas Gerais. A classifica??o da capacidade produtiva foi realizada por meio de quatro m?todos: curva-guia, predi??o dos par?metros, equa??o das diferen?as e rede neural artificial. Em todos os m?todos foi adotada uma idade de refer?ncia de 72 meses e foram obtidas tr?s classes de capacidade produtiva (superior, m?dia e inferior). Para os m?todos da curva-guia e equa??o das diferen?as foi empregado o modelo de Schumacher linearizado e para o m?todo da predi??o dos par?metros foi utilizado o modelo log?stico. Na classifica??o por meio de RNA utilizou-se a rede auto-organiz?vel de Kohonen, sendo o agrupamento realizado em dois est?gios. Na primeira etapa os dados foram utilizados para treinar a rede e na segunda etapa os vetores de pesos sin?pticos foram agrupados utilizando o m?todo do vizinho mais distante. Foram testadas diferentes entradas (E) para as RNA: E1- volume total com casca (V); E2- ?rea basal (B); E3- altura total (Ht); E4- altura dominante (Hd); E5- di?metro quadr?tico m?dio (q); e E6- V, B, Ht, Hd, q e n?mero de ?rvores por hectare. A sele??o da entrada foi realizada por meio da an?lise discriminante, sendo selecionada a entrada E6 com 83,6% de acerto geral. Os m?todos foram comparados em termos de porcentagem de coincid?ncia na aloca??o dos talh?es, ?rea e volume por classe de capacidade produtiva. As classes obtidas pelos m?todos da curva-guia e equa??o das diferen?as foram muito semelhantes de acordo com os crit?rios de compara??o adotados. A classifica??o pelo m?todo da predi??o dos par?metros n?o foi semelhante aos outros m?todos. A classifica??o por meio de rede neural artificial foi eficiente quando comparada aos demais m?todos em termos de porcentagem de coincid?ncia na aloca??o dos talh?es, ?rea e estoque volum?trico por classe de capacidade produtiva. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Ci?ncia Florestal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / The objective of this work was to evaluate the efficiency of the classification of the productive capacity of eucalyptus forest stands (Eucalyptus ssp.) through artificial neural network (ANN). The data used came from continuous forest inventories conducted in stands of Eucalyptus ssp. located in the state of Minas Gerais. The classification of the productive capacity was accomplished through four methods: guide curve, prediction of the parameters, equation of the differences and artificial neural network. In all methods, a reference age of 72 months was adopted and three productive capacity classes (upper, middle and lower) were obtained. For the methods of the guide curve and equation of the differences was used the linearized Schumacher model and for the method of the prediction of the parameters was used the logistic model. In the classification by ANN was used the self-organizing network Kohonen, which the grouping was performed in two stages. In the first step the data were used to train the network and in the second step the vectors of synaptic weights were grouped using the method of the most distant neighbor. Different entries (E) for RNA were tested: E1- total volume with bark (V); E2- basal area (B); E3- total height (Ht); E4- dominant height (Hd); E5- square mean diameter (q); and E6- V, B, Ht, Hd, q and number of trees per hectare. The selection of the input was performed through the discriminant analysis, and the E6 input was selected with 83.6% of the general hit. The methods were compared in terms of coincidence percentage in the allocation of stands, area and volume by class of productive capacity. The classes obtained by the guide curve methods and equation of the differences were very similar according to the adopted criteria of comparison. Classification by the method of parameter prediction was not similar to the other methods. The classification by artificial neural network was efficient when compared to the other methods in terms of coincidence percentage in the allocation of stands, area and volumetric stock by productive capacity class.

La simulation fine de systèmes d'OA à grand champ de type MOAO ou LTAO pour l'ELT se heurte à deux problématiques: l'augmentation du nombre de degrés de liberté du système. Cette augmentation rend les codes de simulation classiques peu utilisables, en particulier en ce qui concerne les processus d'inversion et de calcul matriciel. La complexité des systèmes, combinant EGL et EGN, grands miroirs déformables couvrant tout le champs et des miroirs dédiés dans les instruments eux mêmes, des rotations différentielles de pupille et ou de champs. Cette complexité conduit aux développements de procédures nouvelles d'étalonnage, de filtrage et fusion de données, de commande distribuée ou globale. Ces procédures doivent être simulées finement, comparées et quantifiées en termes de performances, avant d'être implantées dans de futurs systèmes. Pour répondre à ces deux besoins, le LAM développe en collaboration avec l'ONERA un code de simulation complet, basé sur une approche de résolution itérative de systèmes linéaires à grand nombre de paramètres (matrices creuses). Sur cette base, il incorpore de nouveaux concepts de filtrage et de fusion de données pour gérer efficacement les modes de tip/tilt/defocus dans le processus complet de reconstruction tomographique. Il permettra aussi, de développer et tester des lois de commandes complexes ayant à gérer un la combinaison du télescope adaptatif et d'instrument post-focaux comportant eux aussi des miroirs déformables dédiés.La première application de cet outil se fait naturellement dans le cadre du projet EAGLE, un des instruments phares du futur E-ELT, qui, du point de vue de l'OA combinera l'ensemble de ces problématiques. / Refined simulation tools for wide field AO systems on ELTs present new challenges. Increasing the number of degrees of freedom makes the standard simulation's codes useless due to the huge number of operations to be performed at each step of the AO loop process. The classical matrix inversion and the VMM have to be replaced by a cleverer iterative resolution of the Least Square or Minimum Mean Square Error criterion. For this new generation of AO systems, concepts themselves will become more complex: data fusion coming from multiple LGS and NGS will have to be optimized, mirrors covering all the field of view associated to dedicated mirrors inside the scientific instrument itself will have to be coupled using split or integrated tomography schemes, differential pupil or/and field rotations will have to be considered.All these new entries should be carefully simulated, analysed and quantified in terms of performance before any implementation in AO systems. For those reasons i developed, in collaboration with the ONERA, a full simulation code, based on iterative solution of linear systems with many parameters (sparse matrices). On this basis, I introduced new concepts of filtering and data fusion to effectively manage modes such as tip, tilt and defoc in the entire process of tomographic reconstruction. The code will also eventually help to develop and test complex control laws who have to manage a combination of adaptive telescope and post-focal instrument including dedicated DM.

Retail is shifting from physical shopping experience to a more online experience. However, the transition is not happening without pains and both consumers and companies alike face challenges when it comes to utilizing all the benefits that the flexibility brings. One of the biggest issues that the online fashion industry is facing, is product evaluation and the resulting high returns rate. Customers are unable to fully evaluate the products due to, for example, insufficient information, faulty information and the fact that size guides are not reliable, which are incentives for the customers to send the products back. Thus, the aim of this thesis is to investigate and determine what the key challenges that the online fashion companies face related to their most common product evaluation tools and what effects those challenges have on the companies. Further, this thesis evaluates how implementing an augmented reality tool, the Augment app would affect those challenges. Finally, this study investigates how implementing the Augment app would affect the Swedish online fashion retailers’ competitiveness. To answer these questions, a qualitative multi-case study was conducted with three Swedish online fashion retailers. Conducting an embedded multi-case study allowed for meaningful and generalizable findings as it allowed for both within-case analysis as well as cross-case analysis. The results of the study found that companies face challenges in regards to providing quality customer service, ensuring e-satisfaction as well as reducing the high percentage of customer product returns for the Swedish online retailers. Further, the study found that the Augment app could not automatically solve all of the challenges on its own. Rather, the Augment app would act as a complement to the current product evaluation tools and be a most welcome addition. Further, by implementing it, a company could build sustainable competitive advantage.

Dans la cochlée, la réponse couplée de sa structure et de son fluide interne peut être représentée sous la forme d’une onde dont les caractéristiques varient en fonction de la position longitudinale. La méthode asymptotique Wentzel-Kramers-Brillouin est adaptée à la modélisation de ce type d’onde. Dans un premier temps, cette méthode est reprise. Un modèle numérique est également développé et les résultats des deux méthodes sont comparés. Dans un deuxième temps, la métohde Wentzel-Kramers-Brillouin est améliorée afin de prendre en compte le couplage entre plusieurs ondes. Le couplage d’un mode propagatif avec des modes évanescents est réalisé et validé. Dans la cochlée, la stimulation des cellules cillées résulte d’un mouvement de cisaillement de la membrane tectoriale et de flexion de la membrane basilaire. Le couplage entre ces deux modes de déformation est encore peu connu et offre une perspective intéressante. Dans un troisième temps, une nouvelle méthode couplant la méthode Wentzel-Kramesr Brillouin et une méthode numérique est développée et validée afin de déterminer des modes transverses de propagation. Cette méthode est appliquée à la mécanique cochléaire et un mode de flexion de la membrane basilaire et un mode relatif à un mouvement de cisaillement de la membrane tectoriale sont déterminés. Enfin, une expérience inspirée des cochlées artificielles est conçue et réalisée. La propagation d’ondes est observée et la tonotopie est mesurée et comparée aux modèles. Afin de limiter la réflexion des ondes et de faciliter la mesure, une combinaison originale du trou noir acoustique avec une lame de largeur variable est utilisée. / The cochlea is the organ of hearing for humans and mammals. It is often modelled as an inhomogeneous waveguide. A travelling wave propagates along the fluid structure coupled waveguide. The mechanical impedance of the structure is varying and provides a frequency place relation. The asymptotic method Wentzel-Kramers-Brillouin allows to solve for the basilar membrane vibration. The evanescents modes are taken into account to provide a better representation compared to the numerical models. As a second step, the finite elements method is used to solve for the transversal modes while the WKB Approximation deals with the longitudinal propagation. The first flexural mode of the basilar membrane is shown. The second propagative mode reveals a shearing motion of the tectorial membrane which can help stimulating the hair cells. An over-size artificial cochlea is designed and built. Thanks to an acoustic black hole, used as a anechoic end, travelling waves are observed on this device. Reflected waves are attenuated and the interferences with incident waves reduced. Mode coupling could be applied not only to evanescent modes but also to propagatives ones. Perspectives for the adaptation of the WKB method to fluid structure inhomogeneous waveguides, and particularly to the immersed acoustic black hole, seem to be very promising.

Text in Afrikaans, abstract in Afrikaans and English / The development of leadership potential in adolescents cannot be approached in a haphazard manner. It ought to occur on the basis of a dynamic development model within a structured space. Such a model should not only prepare adolescents for their current leadership role, but also, and more particularly, its very nature should be more career-oriented. The question of what model will strive to equip adolescents with greater entrepreneurially-orientated leadership knowledge, therefore justifiably calls for closer investigation. In this study, an attempt has been made to find a suitable model to meet these needs. With this in mind, a study of the literature on the phenomenon of successful leadership was undertaken. Various relevant aspects that incorporate organisationally-structured management, were also examined. This enabled the researcher to develop a practice-oriented model from a study of the literature. In the implementation of the research design, use was made of qualitative research methods and techniques in order to collect and analyse relevant data. The study entailed 'action research' in which two independant groups were involved. For this purpose, the research results of the second cycle were concentrated on in order to reach findings and draw conclusions, and to make recommendations. This research ultimately revealed that adolescents have a deep need for entrepreneurially-oriented leadership development content. Individual participants also derived significant benefits from the implementation of the model. Owing to the success achieved with this research study, the management team of the school involved has decided to establish a full-time entrepreneurship centre for its pupils. This study can therefore be regarded as a contribution towards meeting the need for similar models in South African schools, in a practical and viable way. / Die ontwikkeling van adolessente se leierspotensiaal is nie iets wat lukraak aangepak kan word nie. Dit behoort aan die hand van 'n dinamiese ontwikkelingsmodel binne 'n gestruktureerde ruimte te geskied. Sodanige model behoort adolessente nie alleen vir hul huidige leierskaprol voor te berei nie, maar behoort in besonder ook 'n meer beroepsgerigte karakter te openbaar. Daar kan dus tereg gevra word hoe die model behoort te lyk wat daarna streef om adolessente met groter entrepreneursgerigte leierskapskennis toe te rus. In hierdie studie is gepoog om vas te stel of 'n geskikte model gevind kan word wat aan bogenoemde behoefte voldoen. Met die oog hierop, is 'n literatuurstudie oor die verskynsel van suksesvolle leierskap onderneem. Daarbenewens is verskeie toepaslike aspekte waarbinne die bestuurswese hom in 'n organisatoriese struktuur vergestalt, ook van nader beskou. Dit het die navorser in staat gestel om 'n praktykgerigte model vanuit 'n literatuurstudie te ontwikkel. Tydens die implementering van die navorsingsontwerp, is van kwalitatiewe navorsingsmetodes en -tegnieke gebruik gemaak om relevante data in te samel en te analiseer. Die studie het voorts die vorm van aksienavorsing aangeneem waarby twee onafhanklike groepe betrek is. Vir die doeleindes is daar op die navorsingsresultate van die tweede siklus gekonsentreer om bevindinge, gevolgtrekkings en aanbevelings te maak. Hierdie navorsing het uiteindelik getoon dat adolessente 'n groot behoefte aan entrepreneursgerigte leierontwikkelingsinhoude toon, terwyl individuele deelnemers baie baat by die implementering van sodanige model gevind het. Op grond van die sukses wat met hierdie navorsingstudie behaal is, het die bestuurspan van die betrokke skool besluit om 'n voltydse entrepreneurskapsentrum vir sy leerlinge tot stand te bring. Hierdie studie kan derhalwe beskou word as 'n bydrae om die behoefte aan soortgelyke modelle in Suid-Afrikaanse skole op 'n prakties-uitvoerbare wyse te vervul. / Psychology of Education / D. Ed. (Sielkundige Opvoedkunde)