Dans le contexte des Sciences de l'Information et de la Technologie, un des challenges est de créer des systèmes de plus en plus petits embarquant de plus en plus d'intelligence au niveau matériel et logiciel avec des architectures communicantes de plus en plus complexes. Ceci nécessite des méthodologies robustes de conception afin de réduire le cycle de développement et la phase de prototypage. Ainsi, la conception et l'optimisation de la couche physique de communication est primordiale. La complexité de ces systèmes rend difficile leur optimisation notamment à cause de l'explosion du nombre des paramètres inconnus. Les méthodes et outils développés ces dernières années seront à terme inadéquats pour traiter les problèmes qui nous attendent. Par exemple, la propagation des ondes dans une cabine d'avion à partir des capteurs ou même d'une antenne, vers le poste de pilotage est grandement affectée par la présence de la structure métallique des sièges à l'intérieur de la cabine, voir les passagers. Il faut, donc, absolument prendre en compte cette perturbation pour prédire correctement le bilan de puissance entre l'antenne et un possible récepteur. Ces travaux de recherche portent sur les aspects théoriques et de mise en oeuvre pratique afin de proposer des outils informatiques pour le calcul rigoureux de la réflexion des champs électromagnétiques à l'intérieur de très grandes structures . Ce calcul implique la solution numérique de très grands systèmes inaccessibles par des ressources traditionnelles. La solution sera basée sur une grille de calcul et un supercalculateur. La modélisation électromagnétique des structures surdimensionnées par plusieurs méthodes numériques utilisant des nouvelles ressources informatiques, hardware et software, pour dérouler des calculs performants, représente le but de ce travail. La modélisation numérique est basée sur une approche hybride qui combine la méthode Transmission-Line Matrix (TLM) et l'approche modale. La TLM est appliquée aux volumes homogènes, tandis que l'approche modale est utilisée pour décrire les structures planaires complexes. Afin d'accélérer la simulation, une implémentation parallèle de l'algorithme TLM dans le contexte du paradigme de calcul distribué est proposé. Le sous-domaine de la structure qui est discrétisé avec la TLM est divisé en plusieurs parties appelées tâches, chacune étant calculée en parallèle par des processeurs différents. Pour accomplir le travail, les tâches communiquent entre elles au cours de la simulation par une librairie d'échange de messages. Une extension de l'approche modale avec plusieurs modes différents a été développée par l'augmentation de la complexité des structures planaires. Les résultats démontrent les avantages de la grille de calcul combinée avec l'approche hybride pour résoudre des grandes structures électriques, en faisant correspondre la taille du problème avec le nombre de ressources de calcul utilisées. L'étude met en évidence le rôle du schéma de parallélisation, cluster versus grille, par rapport à la taille du problème et à sa répartition. En outre, un modèle de prédiction a été développé pour déterminer les performances du calcul sur la grille, basé sur une approche hybride qui combine une prédiction issue d'un historique d'expériences avec une prédiction dérivée du profil de l'application. Les valeurs prédites sont en bon accord avec les valeurs mesurées. L'analyse des performances de simulation a permis d'extraire des règles pratiques pour l'estimation des ressources nécessaires pour un problème donné. En utilisant tous ces outils, la propagation du champ électromagnétique à l'intérieur d'une structure surdimensionnée complexe, telle qu'une cabine d'avion, a été effectuée sur la grille et également sur le supercalculateur. Les avantages et les inconvénients des deux environnements sont discutés.

Pas de résumés en français

Exploiting wireless communications has had an unstoppable growth in the last years. In this attracting scenario, the Ultra Wide Band (UWB) market represents one of the main interesting targets for semiconductor industry. The availability of newer and larger bandwidth in the frequency spectrum (60 GHz and 77 GHz) opens to the possibility of higher bitrates communications. The technology cost reduction is made possible by the use of silicon as semiconductor substrate in the place of classical heterojunction materials. The rapid reduction of the technological node (seen as the thinning of the gate channel) in the new generation of CMOS transistors allows obtaining faster transistors that become usable on V band applications. Therefore, the digital origin of the technology yields two additional advantages. First of all, the facilities for the circuits' production already exist as well as the recipe to create the devices on the substrate. The only additive cost remains the characterization of the technology at mm-wave frequencies. The second fundamental advantage is the possibility to have a complete integration of the system in the same dies with a substantial reduction of packaging and interconnection costs. The objectives of this thesis is the design and the modeling of a complete 60 GHz UWB transceiver starting from the characterization and the optimization of the single subcomponents. The main feature that constitutes the principal constraint of the entire work of this thesis is the high efficiency required for the transceiver front - end. The energy safe capability, in fact, represents the strength point of this project, being the system conceived for wireless sensors network applications. Passive components as inductors and RF lines, have been the first elements that have been designed and characterized. Then the structure of CMOS transistor have been analyzed and characterized in order to obtain performances as higher as possible, in particular for wide transistors. The knowledge acquired during this first part has allowed the developed of high quality factor inductors and high performance transistors (used in the design of upconversion mixer). In addition, the optimum correspondence between simulations and measurements combined with the gained experience on the RF electromagnetic simulations have been exploited to create a series of innovative (when possible) passive structures as baluns, power splitters and power couplers. The second significant part of this work has been consecrated to the modeling of a series of high performance active circuits in the transmitter and the receiver blocks (upconversion mixer, voltage controlled oscillator ad a series of differential and single-ended buffers). The behavior of these structures has been accurately investigated and optimized in order to be later efficiently integrated in the complete transceiver system. The systems are finally integrated in two different dies, transmitter and receiver blocks, and the 60 GHz link has been yield by a demostrator set-up.

Pas de résumés en français

Pas de résumés en français

Les matériaux composites à base de fibre carbone suscitent un intérêt grandissant dans l'industrie en général et avionique en particulier. Très appréciés pour leur résistance exceptionnelle aux efforts de traction ils présentent également un poids bien plus faible que les métaux y compris l'aluminium. Cela permet d'envisager la construction d'aéronefs d'une très grande solidité tout en réduisant significativement leur consommation en carburant. Cependant les composites carbone sont relativement fragiles sous des efforts en flexion ou compression. Leur durée de vie est peu connue et dépend fortement de la géométrie des pièces qui sont souvent surdimensionnées par sécurité. Afin de prévenir d'éventuels accidents et conserver des pièces légères il est indispensable d'évaluer leur état de santé. L'objectif de cette thèse est la conception d'une solution d'instrumentation à base de capteurs miniaturisés en technologie silicium sensibles aux vibrations mécaniques et capables de détecter l'apparition d'un défaut dans la structure. Nous développé un procédé de fabrication simple et robuste pour des capteurs dont l'élément sensible est une jonction PN de type Zéner implémentée dans du polysilicium. Nous avons démontré dans un premier temps une sensibilité aux vibrations mécaniques. La capacité de ces capteurs à faire du suivi de réticulation en autoclave a également été démontrée. La phase suivante a concerné l'étude d'un procédé de packaging souple robuste et modulable pour la mise en réseau des capteurs. Enfin la dernière étape concerne l'étude d'un circuit électronique permettant la lecture du signal et la réduction du bruit de fond.

Thesis (Ph. D.)--Columbia University, 1993. / Department: Art History. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 205-210).

Submitted by Fernanda Faquim Dos Santos (ferfachin@yahoo.com.br) on 2018-06-01T23:44:34Z No. of bitstreams: 1 DISSERTAÇÃO FERNANDA F.SANTOS.pdf: 1996897 bytes, checksum: 3f600e1895c2f870f15395cb5de30a1a (MD5) / Approved for entry into archive by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br) on 2018-06-05T18:33:27Z (GMT) No. of bitstreams: 1 santos_ff_me_jabo.pdf: 1996897 bytes, checksum: 3f600e1895c2f870f15395cb5de30a1a (MD5) / Made available in DSpace on 2018-06-05T18:33:27Z (GMT). No. of bitstreams: 1 santos_ff_me_jabo.pdf: 1996897 bytes, checksum: 3f600e1895c2f870f15395cb5de30a1a (MD5) Previous issue date: 2018-05-07 / Devido ao aumento da expectativa de vida dos animais de estimação, o aparecimento de neoplasias tem se tornado uma importante afecção na Medicina Veterinária. As neoplasias gastrointestinais de cães são pouco diagnosticadas e sua etiologia é desconhecida. As localizações mais frequentes são o jejuno, cólon e reto. Objetivou-se avaliar a Cox-2 por meio de imunohistoquímica e a intensidade de PAS positivo nas amostras de intestinos de cães saudáveis (GS) e com neoplasia (GN). As neoplasias foram classificadas por análise histopatológica. As diferenças foram significativas quando P<0.05 (testes não paramétricos). Nas amostras neoplásicas observou-se imunodetecção acentuada de COX-2, quando comparadas aos cães saudáveis, com diferenças significativas entre os grupos. O mesmo ocorreu para a intensidade de PAS, onde se observou diminuição do número de células caliciformes e aumento na produção de muco nas amostras neoplásicas, enquanto nas amostras saudáveis observou-se marcação intensa nas células caliciformes. Com isso pode-se concluir que a COX está envolvida na capacidade do tumor evadir as defesas do sistema imunológico. Apesar da relação entre o processo inflamatório, mais especificamente o papel das prostaglandinas, e o desenvolvimento e propagação tumoral ser bastante claro, ainda muito se têm a ser esclarecido. / Due to the increase in the life expectancy of the pets, the appearance of neoplasias has become an important affection in the Veterinary Medicine. Gastrointestinal neoplasms of dogs are poorly diagnosed and their etiology is unknown. The most frequent locations are jejunum, colon and rectum. The objective of this study was to evaluate Cox-2 by means of immunohistochemistry and the positive PAS intensity in intestinal samples from healthy dogs (GS) and neoplasia (GN). The neoplasms were classified by histopathological analysis. The differences were significant when P <0.05 (non-parametric tests). In the neoplastic samples, marked COX-2 immunodetection was observed when compared to healthy dogs, with significant differences between groups. The same was observed for PAS intensity, where a decrease in the number of goblet cells and an increase in the mucus production were observed in the neoplastic samples, while in the healthy samples intense marking was observed in the goblet cells. With this we can conclude that COX is involved in the ability of the tumor to evade the defenses of the immune system. Although the relationship between the inflammatory process, more specifically the role of prostaglandins, and tumor development and propagation is very clear, much remains to be elucidated.

Magister Scientiae - MSc (Medical BioSciences) / Despite attempts to develop new drugs to reduce the worldwide mortality rate attributable to tuberculosis (TB), the illness remains a threat. Isoniazid (INH) has been used as a frontline drug for decades. However, several resistant strains of the organism - Mycobacterium tuberculosis (M. tuberculosis) - still emerge. The drug is mainly metabolised by a family of enzymes, arylamine N-acetyltransferases (NAT). The three human NAT genes - NAT1, NAT2 and the pseudogene, NATP - are found on chromosome 18p22. NAT1 and NAT2 are isoenzymes which differ at certain amino acid positions. Subsequently, the differences affect substrate specificity. NAT1 shows specificity to p-aminobenzoic acid (PABA) and paminosalicylate (PAS). Previously, computer algorithms were used to predict the efficacy of the enzyme with regard to the acetylation phenotype it confers. The two which were focused on, Sorting Intolerant From Tolerant (SIFT) program and Polymorphism phenotyping version 2 program (PolyPhen-2), showed conflicting results for the effect of SNPs on the acetylation rate and subsequent enzyme function. Further structural prediction methods were used to test the effect of V231G on the structure and consequent function of the native protein, NAT1.

Pas de résumé en français / The goal of our studies was to test the effect of segmentation, cueing, and 2D/3D presentations to foster complex animation rocessing. The material was an upright mechanical piano system. We used an eye tracking system which provides information about learners’ attention direction during the animation processing. We analyzed the effect of the format presentations and the eye movements during learning. Based on animation and multimedia research background, four experiments were conducted. In the first experiment the effect of the presentation of simplified external representations on learning from complex animation was investigated. Experiment two and three aimed at studying the cognitive processes involved in learning to complex mechanism system with new cueing techniques with spatial-temporal colored tokens. In the fourth experiment, 2D and 3D presentation of the same animated content were compared. Results of these experiments showed that (1) the use of a dual format presentation is better for developing a dynamic mental model from the animation than a single format, (2) the signaling strategies using cued tokens of dual format can guide efficiently learner’s building of mental model and can enhance learner’s comprehension of complex system, (3) a sequential format presentation followed by an animation format presentation helps the learner to understand the key stages of a dynamic process and to create a high quality mental model, (4) 3D animation presentation is better than 2D animation presentation to direct attention on relevant component of the animation. For depth processing, comprehension with 3D animation presentation is better than 2D animation format. Eye tracking measures provided insights into how people understood and learned complex systems. The analysis of eye tracking also contributed to the understanding of the subject’s perceptual processing during learning. Overall, results provide a significant contribution in the field of learning with complex animation. Recommendations in the ergonomics area for the design of animations are proposed.