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Le développement de interaction homme-machine aide les utilisateurs à travailler de manière plus efficace. Les technologies traditionnelles ne peuvent plus satisfaire les nouveaux besoins des applications variées. Enenvironnement 2D WIMP, les périphériques d'entrée isotonique combinés avec un contrôle en position tels que les souris ou touch-pad, souffrent de débrayages qui prennent du temps et rendent l'interaction moins lisse. C'est pire encore lors de l'utilisation d'un petit périphérique avec un grand écran. Les interactions 3D attirent l'attention de nombreux chercheurs. Toutefois, les techniques existantes qui permettent à la fois la navigation et de manipuler les objets ne sont pas naturelles ni suffisamment efficaces pour être totalement acceptées par les utilisateurs. De nouveaux périphériques d'entrée et des techniques d'interaction doivent être proposées afin d'améliorer la qualité de l'interaction. Dans cette thèse, nous proposons deux périphériques d'entrée composés d'une zone isotonique avec un contrôle en position et une zone élastique avec un contrôle en vitesse; La première méthode RubberEdge est une méthode en 2D pour réduire le débrayage et la seconde méthode Haptic Boundary est une méthode 3D qui rend plus efficace les manipulations d'objets et l'exploration de l'environnement virtuel. Pour RubberEdge, nous avons adopté la simulation de rotation d'un disque et un traitement mathématique dans sa fonction de transfert pour garantir un passage lisse du contrôle en position au contrôle en vitesse. Une évaluation d'une tache de sélection en 2D a été réalisée. Le résultat a montré que RubberEdge est 20% plus performant que le contrôle en position. Nous avons ensuite proposé deux modèles prédictifs pour le temps de sélection pour le contrôle en position ainsi que le contrôle hybride de RubberEdge. Nous avons présenté également une mise en oeuvre de RubberEdge pour ordinateur portable. Haptic Boundary permet des manipulations d'objets précises dans sa zone isotonique et la manipulation de la caméra sur sa paroi. Deux types de retour d'effort ont été adoptés pour fournir des mouvements de caméra plus riches et pour éviter un passage de mode explicite qui pourrait augmenter la charge mentale des utilisateurs. La taille et la forme de la zone isotonique ont été choisies avec soin afin de maximiser les avantages du contrôle en vitesse de deux types de retour d'effort. Une évaluation de la tache du montage d'une voiture virtuelle est réalisée. L'expérience a montré que Haptic Boundary est 50% plus performant que l'interface uni-manuelle avec un changement du mode explicite. Après analyse des résultats, un mode d'inspection en orbite est mis en place pour améliorer l'usage de l'Haptic Boundary. / The development of human-computer interaction technologies help people to work more efficiently. Meanwhile, traditional technologies could not fulfill the new born requirements in diverse situations. ln 2D WIMP environment the popular isotonic position control device, such as mouse, touch pad, suffers from clutching which is time-consuming and makes the interaction less smooth. lt is getting worse when using a small input device to interact with a larger screen. 3D interactions attract attentions of many researchers. However, the existing techniques allowing both object and view manipulations are not natural or efficient enough to be totally accepted by users. New input devices and corresponding interaction techniques should be proposed to improve the interaction quality. ln this thesis, we propose two techniques based on isotonic-position and elastic-rate control spaces: 2D RubberEdge for reducing the clutching and 3D Haptic Boundary for efficient object manipulations and exploration in VE. For RubberEdge, we adopted a simulation of the ration of a disc, and a mathematical treatment in its mapping function to guarantee a smooth switch between position and rate control. An evaluation of a 2D selecting task was performed. The result showed that RubberEdge outperforms position-only control by 20%. We then proposed two predictive models for selection time with position-only control and with the hybrid control of RubberEdge. We also presented the first RubberEdge prototype for laptop touchpad. Haptic Boundary allows precise object manipulations inside its isotonic zone and camera manipulation on its boundary. Two kinds of force feedbacks were adopted to provide richer camera motions and to avoid the explicit mode switch which greatly increases user's mentalload. The shape and size of isotonic zone is carefully chosen to maximize the benefit of the rate control with both two force feedbacks. An evaluation of car assembling task was performed. The result showed that Haptic Boundary outperformed the unimanual interface with explicit switch by 50%. After analyze the experiment result, the orbiting inspection is combined to enhance the applicability of Haptic Boundary.

Organic and organometallic electronic materials continue to attract considerable attention among researchers due to their cost effectiveness, high flexibility, low temperature processing conditions and the continuous emergence of new semiconducting materials with tailored electronic properties. In addition, organic semiconductors can be used in a variety of important technological devices such as solar cells, field-effect transistors (FETs), flash memory, radio frequency identification (RFID) tags, light emitting diodes (LEDs), etc. However, organic materials have thus far not achieved the reliability and carrier mobility obtainable with inorganic silicon-based devices. Hence, there is a need for finding alternative electronic materials other than organic semiconductors to overcome the problems of inferior stability and performance. In this dissertation, I research the development of new transition metal based electronic materials which due to the presence of metal-metal, metal-?, and ?-? interactions may give rise to superior electronic and chemical properties versus their organic counterparts. Specifically, I performed computational modeling studies on platinum based charge transfer complexes and d10 cyclo-[M(?-L)]3 trimers (M = Ag, Au and L = monoanionic bidentate bridging (C/N~C/N) ligand). The research done is aimed to guide experimental chemists to make rational choices of metals, ligands, substituents in synthesizing novel organometallic electronic materials. Furthermore, the calculations presented here propose novel ways to tune the geometric, electronic, spectroscopic, and conduction properties in semiconducting materials. In addition to novel material development, electronic device performance can be improved by making a judicious choice of device components. I have studied the interfaces of a p-type metal-organic semiconductor viz cyclo-[Au(µ-Pz)]3 trimer with metal electrodes at atomic and surface levels. This work was aimed to guide the device engineers to choose the appropriate metal electrodes considering the chemical interactions at the interface. Additionally, the calculations performed on the interfaces provided valuable insight into binding energies, charge redistribution, change in the energy levels, dipole formation, etc., which are important parameters to consider while fabricating an electronic device. The research described in this dissertation highlights the application of unique computational modeling methods at different levels of theory to guide the experimental chemists and device engineers toward a rational design of transition metal based electronic devices with low cost and high performance.

No presente trabalho concentramos nossos estudos nas propriedades do sistema GaInP/GaAs, particularmente nas propriedades estruturais das interfaces e sua correlação com as propriedades ópticas. Subdividimos esta dissertação em duas partes principais, a primeira trata da investigação de amostras crescidas por CBE (Chemical Beam Epitaxy), onde no crescimento das interfaces variou-se diversos parâmetros. visando a melhoria do perfil das interfaces. Desse estudo concluímos que o crescimento de uma camada de GaP na primeira interface (GaAs crescido sobre GaInP) pode melhorar sua qualidade. A partir desta informação, na segunda parte, realizamos estudo para um conjunto de amostras crescidas pela técnica MOCVD (Metal Organic Chemical Vapor Deposition) com diferentes larguras de poços, e contendo uma monocamada de GaP na primeira interface. Os dados experimentais obtidos nesta segunda parte foram analisados à luz do modelo dos mínimos locais e absolutos e da mecânica estatística predictiva. A análise dos nossos resultados experimentais, usando os modelos teóricos, mostrou-se consistente e coerente. Ainda, por meio da mecânica estatística predicitiva ajustamos os dados experimentais de PL e obtivemos outras duas grandezas físicas, a energia cinética média dos portadores e o índice entrópico informacional, usados para indicar a qualidade das interfaces. Finalmente, observando que os modelos utilizados descreviam com sucesso os resultados experimentais, passamos a analisar um conjunto de amostras no qual mantivemos todos os demais parâmetros de crescimento fixos e variamos a espessura da camada de GaP na primeira interface. A análise mostrou excelente consistência e coerência dos resultados, permitindo confirmar a potencialidade dos modelos teóricos utilizados no tratamento dos dados experimentais e também ampliar a compreensão sobre o papel da camada de GaP na uniformização das interfaces dos poços quânticos de GaInP/GaAs / In the present work we concentrate our studies in the properties of the GaInP/GaAs quantum wells system, particularly in the structural properties of the interfaces and its correlation with the optic characteristics. We subdivide this work in two main parts, the first one deals with the investigation of samples grown by CBE (Chemical Beam Epitaxy), where in the growth of the interfaces diverse parameters were changed. From this study we conclude that a GaP layer localized first interface (GaAs grown on GaInP) can improve its quality. Using this information, in the second part, we studied a set of samples grown by MOCVD (Metal Organic Chemical Vapor Deposition) containing wells with different widths, and with a GaP monolayer in the first interface. The experimental data obtained in this second part had been analyzed on the light of the local and absolute minimums model and of the predictive statistical mechanics. The analysis of our experimental results, using the theoretical models. revealed be consistent and coherent. Still, by means of the predictive statistical mechanics we fitting the experimental data of fotoluminescence and extracted the average kinetic energy of the carriers and the informational entropic índex, used to indicate the quality of the quantum well interfaces. Finally, observing that the used models provide a very well description of the experimental results, we start to analyze a set of samples in which the growth parameters are fixed except the thickness of the GaP layer at the first interface. The analysis showed the excellent coherence and consistency of the results, allowing to confirm the potentiality of the theoretical models used in the treatment of the experimental data and, also, permited to extend the understanding about the performace of the GaP layer in the improvement of the interface quality in GaInP/GaAs quantum wells

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Tese de mestrado. Tecnologia Multimédia. Faculdade de Engenharia. Universidade do Porto. 2009

Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores (Major Telecomunicações). Faculdade de Engenharia. Universidade do Porto. 2010

Tese de mestrado. Engenharia Informática. 2007. Faculdade de Engenharia. Universidade do Porto

Tese de mestrado integrado. Engenharia Civil (especialização em Vias de Comunicação). Faculdade de Engenharia. Universidade do Porto. 2008

Dissertação apresentada para obtenção do grau de Mestre em Gestão de informação, na Faculdade de Engenharia da Universidade do Porto, sob a orientação do Professor Doutor Joaquim Borges Gouveia