This thesis presents the design of an attitude determination system for small satellites that automatically corrects for attitude drift. Existing attitude determination systems suffer from attitude drift due to the integration of noisy rate gyro sensors used to measure the change in attitude. This attitude drift leads to a gradual loss in attitude knowledge, as error between the estimated attitude and the actual attitude increases. In this thesis a Kalman filter is used to complete sensor fusion which combines sensor observations with a projected attitude based on the dynamics of the satellite. The system proposed in this thesis also utilizes a novel sensor called the stellar gyro to correct for the drift. The stellar gyro compares star field images taken at different times to determine orientation, and works in the presence of the sun and during eclipse. This device provides a relative attitude fix that can be used to update the attitude estimate provided by the Kalman filter, effectively compensating for drift. Simulink models are developed of the hardware and algorithms to model the effectiveness of the system. The Simulink models show that the attitude determination system is highly accurate, with steady state errors of less than 1 degree.

The University of Waterloo Alternative Fuels Team’s participation in EcoCAR: The Next Challenge provided an unparalleled opportunity to execute advanced vehicle technology research with hands on learning and industry leading mentoring from practicing engineers in the automotive industry. This thesis investigates the optimization of the hybrid operating strategy on board the EcoCAR development vehicle. This investigation provides the framework to investigate the pros and cons of different hybrid control strategies, develop the model based design process for controls development in a student team environment and take the learning of this research and apply them to a mule development vehicle. A primary controls development model was created to simulate software controls before releasing to the vehicle level and served as a tool to evaluate and compare control strategies. The optimization routine was not directly compatible with this model and so a compromise was made to develop a simplified vehicle model in the MATLAB environment that would be useful for observing trends but realizing that the accuracy of the results may not be totally consistent with the real world vehicle. These optimization results were then used to create a new control strategy that was simulated in the original vehicle development model. This new control strategy exhibited a 15% gain in fuel economy over the best case from the literature during an Urban Dynamometer Driving Schedule (UDDS) drive cycle. Recommendations for future work include adding charge depletion operation to the simulation test cases and improving the accuracy of the optimization model by removing the simplifications that contributed to faster simulation time. This research has also illustrated the wide variability of drive cycles from the mildly aggressive UDDS cycle having 5 kilowatts average propulsion power to the very aggressive US06 cycle having 19 kilowatts average propulsion power and their impact on the efficiency of a particular control strategy. Understanding how to adapt or tune software for particular drive cycle or driver behaviour may lead to an interesting area of research.

The knee joint plays an essential role in the human musculoskeletal system. It has evolved to withstand extreme loading conditions, while providing almost frictionless joint movement. However, its performance may be disrupted by disease, anatomical deformities, soft tissue imbalance or injury. Knee disorders are often puzzling, and accurate diagnosis may be challenging. Current evaluation approach is usually limited to a detailed interview with the patient, careful physical examination and radiographic imaging. The X-ray screening may reveal bone degeneration, but does not carry sufficient information of the soft tissue conditions. More advanced imaging tools such as MRI or CT are available, but expensive, time consuming and can be used only under static conditions. Moreover, due to limited resolution the radiographic techniques cannot reveal early stage arthritis. The arthroscopy is often the only reliable option, however due to its semi-invasive nature, it cannot be considered as a practical diagnostic tool. Therefore, the motivation for this work was to combine three scientific methods to provide a comprehensive, non-invasive evaluation tool bringing insight into the in vivo, dynamic conditions of the knee joint and articular cartilage degeneration. Electromyography and inverse dynamics were employed to independently determine the forces present in several muscles spanning the knee joint. Though both methods have certain limitations, the current work demonstrates how the use of these two methods concurrently enhances the biomechanical analysis of the knee joint conditions, especially the performance of the extensor mechanism. The kinetic analysis was performed for 12 TKA, 4 healthy individuals in advanced age and 4 young subjects. Several differences in the knee biomechanics were found between the three groups, identifying age-related and post-operative decrease in the extensor mechanism efficiency, explaining the increased effort of performing everyday activities experienced by the elderly and TKA subjects. The concept of using accelerometers to assess the cartilage degeneration has been proven based on a group of 23 subjects with non-symptomatic knees and 52 patients suffering from knee arthritis. Very high success (96.2%) of pattern classification obtained in this work clearly demonstrates that vibroarthrography is a promising, non-invasive and low-cost technique offering screening capabilities.

Thesis (Ph. D.)--Fletcher School of Law and Diplomacy, 2001. / Includes bibliographical references (leaves 305-324).

Thesis (M.S.)--Florida State University, 2006. / Advisor: James R. Simpson, Florida State University, College of Engineering, Dept. of Industrial Engineering. Title and description from dissertation home page (viewed Sept. 22, 2006). Document formatted into pages; contains ix, 95 pages. Includes bibliographical references.

Submitted by Noeme Timbo (noeme.timbo@metodista.br) on 2017-01-27T14:19:22Z No. of bitstreams: 1 JulianaG.Santos.pdf: 965373 bytes, checksum: e9ac2dac85934fdcd07c615473464973 (MD5) / Made available in DSpace on 2017-01-27T14:19:22Z (GMT). No. of bitstreams: 1 JulianaG.Santos.pdf: 965373 bytes, checksum: e9ac2dac85934fdcd07c615473464973 (MD5) Previous issue date: 2016-11-23 / Personal data protect procedures are organizational tools that properly used by the employee help in the prevention and personal data protect within a safety and transparency organizational limit. This study analyzed the factors that have influenced the perception of the employees of Brazilian organizations about perceived benefits of compliance on the policies established in the prevention and protection of personal data. The research was conducted through a quantitative research approach with analysis of structural equations and the study data were collected through a survey tool to obtain a valid sample of 220 respondents. The study concluded that trust in organization and the risk of loss of personal data are stimulus that positive influence the benefits perceived of the compliance. The results also show that the employees who had your data improperly used, reduces your credibility in organizational controls and increases their perceived risk of privacy loss. The result of the study can help organizations managers to achieve greater adherence of employees with regard to personal data protection policy of organization in which they work, in addition to demonstrate the importance of credibility in internal controls and trust in the organization as predictors of perceived benefits of compliance. / Políticas de proteção de dados pessoais são ferramentas organizacionais que, se usadas de maneira adequada pelos colaboradores auxiliam na prevenção e proteção dos dados pessoais dentro de um limite de segurança e transparência organizacional. Este estudo objetiva analisar os fatores que influenciam a percepção dos empregados de organizações brasileiras quanto aos benefícios percebidos de compliance sobre as políticas estabelecidas na prevenção e proteção dos dados pessoais. A pesquisa foi conduzida através de uma abordagem de investigação quantitativa, com análise por equações estruturais e os dados do estudo foram coletados por meio de um instrumento de pesquisa com obtenção de uma amostra válida de 220 respondentes. O estudo concluiu que a Confiança na organização e a Percepção do risco de perda dos dados pessoais são estímulos que influenciam positivamente os benefícios percebidos de compliance. Os resultados também evidenciam que o empregado que teve seus dados utilizados de forma indevida reduz a sua credibilidade nos controles organizacionais e aumenta a sua Percepção do risco de perda de privacidade. O resultado do estudo pode auxiliar gestores de organizações a obter maior aderência dos empregados quanto às políticas de proteção de dados pessoais da organização em que trabalham, além de demonstrar a importância da credibilidade nos controles internos e a confiança na organização como preditores dos benefícios percebidos de compliance.

L’ocytocine est un petit peptide synthétisé par des neurones de l’hypothalamus. Il est connu pour ses rôles dans la reproduction et les interactions sociales, en particulier dans les interactions mère-enfants, mais possède également un effet analgésique endogène. Au cours de cette thèse, j’ai cherché à comprendre plus en détail les circuits qui sous-tendent son effet analgésique. Dans un second temps j’ai cherché à déterminer si une séparation maternelle précoce, qui affecte les interactions mère-enfants, perturbe les réponses à la douleur et l’analgésie ocytocinergique chez la descendance. Ces travaux ont permis d’identifier un groupe de neurones ocytocinergiques dans l’hypothalamus, capables de diminuer la douleur par une double action. D’une part ils inhibent directement la transmission de l’information nociceptive dans la moelle épinière, et d’autre part contrôlent l’activité de neurones à ocytocine libérant la molécule dans la circulation sanguine. Notre étude sur la séparation maternelle démontre qu’elle induit une hypersensibilité à la douleur à l’âge adulte et un dysfonctionnement de l’analgésie endogène ocytocinergique. / Oxytocin is a small peptide synthesized in hypothalamic neurons. She is well known for its roles in reproduction and social interactions, especially in mother-infant interactions, but also displays analgesic effects. During this thesis, I tried to get a better understanding of the circuits underlying OT analgesia. Then, I tried to determine if neonatal maternal separation, affecting mother-infant interactions, alters adult pain responses and oxytocin analgesia. This work allowed to identify a subgroup of oxytocinergic neurons in the hypothalamus, able to decrease pain through a dual action. They directly inhibit nociceptive transmission in the spinal cord and control the activity of another population of oxytocinergic neurons releasing the peptide in the bloodstream. Our work on maternal separation shows that it induces nociceptive hypersensitivity at adulthood, and a dysfunction in oxytocin analgesia.

Le projet LIGO a pour but la détection et l'étude d'ondes gravitationnelles via un réseau de détecteurs. LIGO possède deux détecteurs d'architecture et de fonctionnement identiques, situés aux États-Unis. Chaque détecteur est une version améliorée d'un interféromètre de Michelson avec des bras optiques de 4 km de long. Ces interféromètres ont observé une onde gravitationnelle pour la première fois en septembre 2015, suivi par cinq autres détections à ce jour. Ces détections marquent le début d™une nouvelle ère pour l'astrophysique, en liaison étroite avec la physique des trous noirs et des étoiles à neutrons. Depuis, un grand nombre d'activités sont en développement pour perfectionner les interféromètres. Cette thèse a pour objectif d'améliorer le temps de service des détecteurs, en répondant en particulier à deux problématiques majeures : le problème des impacts environnementaux, et notamment celui des tremblements de terre, ainsi que le problème lié à des couplages opto-mécaniques instables dans les cavités optiques, appelés instabilités paramétriques. Les stratégies de contrôle et les outils développés pour résoudre ces problématiques sont présentés. Les résultats prémilinaires montrent une réduction du temps d'arrêt généré par les tremblements de terre d'environ 40%. De plus, le dispositif ‚Acoustic Mode Damper™ développé pendant la thèse devrait complètement résoudre le problème des instabilités paramétriques pour LIGO. En conclusion, il sera démontré en quoi les problématiques résolues ont permis d'améliorer le cycle de service des détecteurs de LIGO de 4,6%, ce qui correspond à une augmentation du nombre d'ondes gravitationnelles détectées par an de 14%. / The LIGO project is a large-scale physics experiment the goal of which is to detect and study gravitational waves of astrophysical origin. It is composed of two instruments identical in design, located in the United States. The two instruments are specialized versions of a Michelson interferometer with 4km-long arms. They observed a gravitational-wave signal for the first time in September 2015 from the merger of two stellar-mass black holes. This is the first direct detection of a gravitational wave and the first direct observation of a binary black hole merger. Five more detections from binary black hole mergers and neutron stars merger have been reported to date, marking the beginning of a new era in astrophysics. As a result of these detections, many activities are in progress to improve the duty cycle and sensitivity of the detectors. This thesis addresses two major issues limiting the duty cycle of the LIGO detectors: environmental impacts, especially earthquakes, and the issue of unstable opto-mechanical couplings in the cavities, referred to as parametric instabilities. The control strategies and tools developed to tackle these issues are presented. Early results have shown a downtime reduction during earthquakes of ~40% at one of the LIGO sites. Moreover, the electro-mechanical device called ‚Acoustic Mode Damper™ designed and tested during the thesis should completely solve the issue of parametric instabilities for LIGO. In conclusion, we will show that the problems tackled in this thesis improved the overall duty cycle of LIGO by 4.6%, which corresponds to an increase of the gravitational-wave detection rate by 14%.

Submitted by Rodrigo dos Santos Barbosa (rdsbar@gmail.com) on 2016-06-13T19:54:58Z No. of bitstreams: 1 Tese.pdf: 895418 bytes, checksum: 64d50c7a9b78e9d3f89b6737e052eb58 (MD5) / Approved for entry into archive by Letícia Monteiro de Souza (leticia.dsouza@fgv.br) on 2016-06-13T21:06:35Z (GMT) No. of bitstreams: 1 Tese.pdf: 895418 bytes, checksum: 64d50c7a9b78e9d3f89b6737e052eb58 (MD5) / Made available in DSpace on 2016-06-13T22:04:05Z (GMT). No. of bitstreams: 1 Tese.pdf: 895418 bytes, checksum: 64d50c7a9b78e9d3f89b6737e052eb58 (MD5) Previous issue date: 2016-05-17 / My dissertation focuses on dynamic aspects of coordination processes such as reversibility of early actions, option to delay decisions, and learning of the environment from the observation of other people’s actions. This study proposes the use of tractable dynamic global games where players privately and passively learn about their actions’ true payoffs and are able to adjust early investment decisions to the arrival of new information to investigate the consequences of the presence of liquidity shocks to the performance of a Tobin tax as a policy intended to foster coordination success (chapter 1), and the adequacy of the use of a Tobin tax in order to reduce an economy’s vulnerability to sudden stops (chapter 2). Then, it analyzes players’ incentive to acquire costly information in a sequential decision setting (chapter 3). In chapter 1, a continuum of foreign agents decide whether to enter or not in an investment project. A fraction λ of them are hit by liquidity restrictions in a second period and are forced to withdraw early investment or precluded from investing in the interim period, depending on the actions they chose in the first period. Players not affected by the liquidity shock are able to revise early decisions. Coordination success is increasing in the aggregate investment and decreasing in the aggregate volume of capital exit. Without liquidity shocks, aggregate investment is (in a pivotal contingency) invariant to frictions like a tax on short term capitals. In this case, a Tobin tax always increases success incidence. In the presence of liquidity shocks, this invariance result no longer holds in equilibrium. A Tobin tax becomes harmful to aggregate investment, which may reduces success incidence if the economy does not benefit enough from avoiding capital reversals. It is shown that the Tobin tax that maximizes the ex-ante probability of successfully coordinated investment is decreasing in the liquidity shock. Chapter 2 studies the effects of a Tobin tax in the same setting of the global game model proposed in chapter 1, with the exception that the liquidity shock is considered stochastic, i.e, there is also aggregate uncertainty about the extension of the liquidity restrictions. It identifies conditions under which, in the unique equilibrium of the model with low probability of liquidity shocks but large dry-ups, a Tobin tax is welfare improving, helping agents to coordinate on the good outcome. The model provides a rationale for a Tobin tax on economies that are prone to sudden stops. The optimal Tobin tax tends to be larger when capital reversals are more harmful and when the fraction of agents hit by liquidity shocks is smaller. Chapter 3 focuses on information acquisition in a sequential decision game with payoff complementar- ity and information externality. When information is cheap relatively to players’ incentive to coordinate actions, only the first player chooses to process information; the second player learns about the true payoff distribution from the observation of the first player’s decision and follows her action. Miscoordination requires that both players privately precess information, which tends to happen when it is expensive and the prior knowledge about the distribution of the payoffs has a large variance. / A presente tese concentra-se em aspectos dinâmicos de processos que envolvem coordenação entre agentes em ambientes com interação estratégica. Propomos utilizar os chamados global games para estudar a capacidade de uma Tobin tax elevar a probabilidade de sucesso em um ambiente em que investidores internacionais sujeitos a choques de liquidez precisam coordenar suas decisões de investimento (capítulo 1), e reduzir a vulnerabilidade de uma economia aberta a fluxos internacionais de capitais a sudden stops (capítulo 2). Também, investigamos o problema da aquisição de informação em jogos sequenciais com informação incompleta e complementaridade em ações (capítulo 3). No capítulo 1, agentes estrangeiros decidem se entram ou não em um projeto, cujo sucesso depende em parte da capacidade dos mesmos em coordenarem suas escolhas. Uma fração λ desses investidores é afetada por restrições de liquidez no segundo período do modelo e é forçada a se retirar do projeto ou impedida de entrar, dependendo de suas respectivas escolhas no primeiro período. Agentes não afetados pelo choque de liquidez possuem a opção de reavaliar decisões tomadas no primeiro estágio do jogo. É assumido que a probabilidade de sucesso do projeto de investimento é crescente no volume total de capital que a economia recebe, mas decrescente no volume de capitais que deixa a economia no segundo período. Na ausência de choques de liquidez (λ = 0), o volume de capital que é recebido em um estado pivotal para o sucesso do projeto de investimento independe da existência de um imposto sobre capitais de curto prazo. Como tal imposto sempre desestimula saídas de capitais, uma Tobin tax sempre favorece as chances de sucesso em uma economia em que λ = 0. Contudo, na presença de choques de liquidez, o volume total de investimento que a economia recebe torna-se decrescente em um imposto incidente sobre capitais de curto prazo. Neste caso, uma Tobin tax pode prejudicar as chances do processo de coordenação ser bem sucedido, caso o benefício de reduzir o volume de saída de capitais não seja suficientemente grande. O capítulo 2 estuda os efeitos de uma Tobin tax no mesmo cenário do capítulo 1, porém considera que a extensão da restrição de liquidez a que os agentes podem estar sujeitos é aleatória. Neste modelo, identificamos condições sob as quais uma Tobin tax reduz a probabilidade de se observar um sudden stop e eleva o bem estar no único equilíbrio de uma economia onde a probabilidade de ocorrência de um choque de liquidez é pequena, mas a magnitude de tal choque pode ser significativa. O capítulo final investiga o problema de aquisição de informação em um jogo sequencial com 2 agentes, externalidade informacional e complementaridade em ações. Demonstramos que, quando o custo de aquisição de informação é pequeno relativamente ao incentivo que os agentes possuem para coordenarem suas ações, apenas o primeiro jogador escolhe adquirir novas informações a respeito da distribuição dos payoffs, e o jogador 2 sempre segue a ação escolhida pelo jogador 1. Probabilidade positiva de se observar divergência em ações requer que ambos os jogadores processem informação privadamente, o que tende a ocorrer quando o custo de aquisição de informação é baixo e a distribuição a priori dos payoffs possui variância elevada.

Orientador: Dr. Alfeu J. Sguarezi Filho / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2016. / A energia eólica é uma fonte de energia renovável com diversas vantagens e sua participação na matriz energética mundial está crescendo a cada ano. Nos últimos anos, as plantas eólicas têm passado por grandes mudanças devido às novas tecnologias desenvolvidas para as Smart Grids (SG). Cada vez mais, os sistemas de conversão de energia eólicos estão utilizando arquiteturas de comunicação mais desenvolvidas para possibilitar o compartilhamento de dados e medidas em fazendas eólicas inteligentes. Nesse contexto, a proposta desse estudo é um controle sem fio para um gerador de indução gaiola de esquilo (GIGE) de velocidade variável conectado coma rede elétrica. O sistema de comunicação sem fio é empregado para enviar as potências de referência para o controlador do GIGE com a confiabilidade necessária para garantir a qualidade da energia fornecida pelo aerogerador. Neste trabalho, no controle do gerador é utilizada a técnica de controle do Controle Direto de Torque (CDT) e controle orientado pela tensão (COT) para a conexão com a rede elétrica. Para o sistema de comunicação sem fio, foram utilizadas duas estratégias de baixo custo e ampla cobertura nacional, baseadas nas redes de dados GPRS e EGPRS. O desempenho do sistema é avaliado através de diversas simulações e testes. / Wind energy is a renewable source of energy with several advantages and the participation in the global energy matrix is increasing every year. In recent years, the wind farms were changing with the advance of new technologies developed for the Smart Grid (SG). Increasingly, wind energy conversion systems are using more developed communication architectures to enable data sharing and intelligent measures in wind farms. In this context, the purpose of this study is a wireless controller for a variable speed Squirrel Cage Induction Generator (SCIG) connected to the grid. The wireless system is used to send the reference powers for SCIG controller with the reliability needed to ensure the quality of the power supplied by the wind turbine. In this paper, in the generator's control is used the Control Direct Torque (CDT) technique and Control-Driven Voltage (COT) technique for connection to the power grid. For the wireless communication system, they used two low-cost strategies with national coverage, based on GPRS and EGPRS data networks. The system performance is evaluated through various simulations and tests.