L’objectif de nos travaux est de mettre en place une méthode pour modéliser le comportement de la dégradation de moteurs aéronautiques à partir de données de retour d’expérience en vue de quantifier l’impact sur le niveau de sécurité des vols. Ces modèles tiennent compte d'un composant dont les mécanismes de défaillance sont en concurrence vis-à-vis d’un événement final (événement redouté rare) et de la politique de maintenance préventive. Nous souhaitons ainsi estimer la fiabilité d'un composant et étudier l'impact d'une nouvelle périodicité de maintenance sur cette fiabilité. Un algorithme d'optimisation des différentes périodicités de maintenances préventives appliquées au composant est également proposé. / The aim of our studies is to propose a statistical model of turboshaft engines ageing behaviour in order to improve the reliability level assessment. Field and repair data feedback are used to fit our model. This model takes into account one component whose failure mechanisms are in competition with respect to a final event and scheduled maintenance policy. We want to estimate reliability of engine component and, for instance, optimize the preventive maintenance policy.

A presente tese tem o objetivo de analisar o processo de consolidação da indústria aeronáutica brasileira a partir de três possibilidades de geração de tecnologia para produtos ou processos: o criar, o copiar e o comprar pronto. O \"criar\" significa aqui a opção de desenvolver tecnologias próprias, autóctones, geradas em instituições ou empresas do próprio país e utilizadas em projetos e programas próprios, que garantam, ou possam garantir soberania econômica, política, estratégica. Para o desenvolvimento desse tipo de tecnologia de produtos e/ou processos é fundamental formar pessoal, formar grupos que dêem sustentação aos processos. O \"criar\" também é influenciado por fatores relacionados aos interesses dos países mais ricos. O \"copiar\" envolve uma forma de produzir que o Brasil já tinha experimentado na indústria de construção aeronáutica, com o exemplo das fábricas de aviões criadas pelo governo, na primeira metade do século XX, que produziam \"sob licença\", mas é uma forma de produzir que o Brasil já experimentava também em outras indústrias que demandam alguma \"tecnologia\". Muitas vezes, \"copiar\" está associado às \"caixas pretas\", sendo que, nesse caso o país não é o dono da \"caixa preta\". Esse tipo de produção pode ser interessante para países que não almejam um real desenvolvimento tecnológico e que servem como base de produção por possuírem mão-de-obra barata, ou incentivos fiscais, ou matéria-prima abundante, ou todas as condições juntas. Finalmente o \"comprar pronto\", é sempre a opção mais rápida, mais imediata, aquela a ser tomada por qualquer país, instituição, empresa ou grupo que não pode esperar por nenhuma das anteriores. É também a opção que deixará o país, instituição, empresa ou grupo mais empobrecido, do ponto de vista do desenvolvimento tecnológico. Pois estará adquirindo um \"produto\", seja ele um bem ou um processo do qual, uma vez cumprida sua função, seu tempo de uso, não restará nada. No caso específico da indústria aeronáutica, o objetivo é investigar e analisar a motivação, as propostas, as decisões, o planejamento, os encaminhamentos e os 12 resultados do projeto de reconstrução da indústria aeronáutica brasileira promovida por um grupo de militares da Aeronáutica, a partir da criação do Instituto Tecnológico de Aeronáutica, em 1950 e do Centro Técnico de Aeronáutica, em 1953. O termo \"reconstrução\" é utilizado porque a indústria de construção aeronáutica no Brasil é mais antiga do que esse projeto e, embora as iniciativas anteriores não tenham obtido o mesmo sucesso da EMBRAER, algumas delas já tinham sido incluídas em planejamentos de desenvolvimento nacional. Assim, nesta análise o sucesso da Empresa Brasileira de Aeronáutica, criada em 1969, pode ser compreendido dentro do projeto modernizador das Forças Armadas e da construção do projeto do Brasil Potência, o que justificaria os investimentos governamentais no financiamento da criação e manutenção da empresa, sem os quais sua viabilização e sucesso não seriam possíveis. / The purpose of this thesis is to analyze the process of the Brazilian aeronautical industry consolidation out of three perspectives of generating technology for products or processes: creating, copying and buying readymade. \"Creating\" means the choice of developing proper technologies, and \"made in the country\" by national institutions or companies which are used in internal projects and programs that may ensure economic, political and strategic sovereignty. For the development of this type of product and/or process technology, the formation of appropriate personal is basic to create groups that give support for these processes. \"Creating\" is also influenced by factors related to the interests of the richest countries. \"Copying\" means a well-known formula of production that Brazil had already tried in the aeronautical industry construction. As an example, the industry of airplanes created by the government in the first half of the 20th century produced them \"under license\". In addition, it was a form of production that Brazil also tried in some other industries which demanded some \"technology\". Due to the lack of the scientific domain of the \"black boxes\", the countries that are not the technology owner have to bear the disadvantages of \"copying\". This type of production may be interesting for countries that do not have real technological development and serve only as a production base because of their low manpower cost, tax incentives, abundant raw material or all of them together. Finally, \"buying readymade\" is always the fastest and the most immediate choice that can be taken by any country, institution, company or group that cannot wait for any of the two previous perspectives. It is also the option that will contribute more rapidly for the technological impoverishment, considering that the institution acquires some \"product\", either a property or a process, and after its use, nothing of it will remain. In the specific case of the aeronautics industry, the aim is to investigate and to analyze 14 the motivation, the proposals, the decisions, the planning and the results of the reconstruction of Brazilian industry, implemented by an Air Force military group, after the creation of the Technological Institute of Aeronautics (ITA), in 1950 and the Aeroespace Technical Center (CTA), in 1953. The term \"reconstruction\" is employed because the Brazilian aeronautics industry in Brazil is older than this project and, although previous initiatives did not achieve the same success as EMBRAER, some of them had already been included in the national development program. From this point of view, the success of EMBRAER, created in 1969, can be included in the modernizing project of the Armed Forces and in the construction of a \"Brazilian Power\". This idea could justify the governmental investments in the creation and maintenance of an industry, without which its viability and success would not be possible.

Ocorre atualmente um movimento de aumento da importância que a manutenção da segurança da informação vem adquirindo em redes de informação de crítica. Ao longo das últimas décadas a utilização de ferramentas criptográficas, especialmente aquelas baseadas em problemas de díficil solução computacional, foram suficientes para garantir a segurança dos sistemas de comunicação. Contudo, o desenvolvimento da nova técnica de processamento de informação conhecida como computação quântica e os resultados téoricos e experimentais apresentados por esta mostram que é possível inviabilizar alguns dos sistemas de criptografia atuais amplamente utilizados. A existência de tal vulnerabilidade representa um fator crítico em redes em que falhas de segurança da informação podem estar associadas a riscos de segurança física. Uma alternativa para os métodos criptográficos atuais consiste na utilização de sistemas quânticos na obtenção de um método criptográfico, o que se conhece como criptografia quântica. Este novo paradigma tem seu fundamento resistente mesmo na presença de capacidade tecnológica ilimitada, incluindo o cenário com disponibilidade de computação quântica. Este trabalho tem como objetivo levantar os impactos que o desenvolvimento da computação quântica têm sobre a segurança dos atuais sistemas criptográficos, apresentar e desenvolver alternativas de protocolos de criptografia quântica disponíveis, e realizar um estudo de caso por meio da avaliação da utilização de criptografia quântica no contexto da Aeronautical Telecommunication Network (ATN). Isto é feito por meio do desenvolvimento de um ambiente de simulacão que permite avaliar o comportamento de um protocolo de criptografia quântica em um cenário em um ambiente com requisitos de missão crítica, como é o caso da ATN. / The importance of security maintenance in critical information networks has been rising in recent times. Over the past decades, the utilization of cryptography tools, mainly those based on computationally intractable problems, was enough to ensure the security of communications systems. The development of the new information processing technique known as quantum computation and the theoretical and experimental results showed by this approach demonstrated that could be possible to cripple the current widely used cryptography techniques. This vulnerability represents a critical issue for networks where a security fault could be associated to a safety fault. An alternative for the current cryptography methods consists in the utilization of quantum systems to obtain a new cryptographic method. The new paradigm presented by this approach has solid principles even in the presence of unlimited computational capacity, including the scenario with availability of quantum computation. The aim of this work is the assessment of impacts that the development of quantum computation has over the current cryptographic methods security, the presentation and development of alternatives based on quantum cryptography protocols, and the development of a case study using the case of Aeronautical Telecommunication Network (ATN). This aim is reached by means of the development of a simulation environment that allows the evaluation of a quantum cryptography protocol behavior in an environment with mission critical requirements, like the ATN case.

Made available in DSpace on 2017-07-10T15:14:20Z (GMT). No. of bitstreams: 1 DissertacaoEdsonVanzella.pdf: 640885 bytes, checksum: 49bfc52db759a282f70d70ded3f85012 (MD5) Previous issue date: 2015-03-03 / The influence of the addition of biodiesel on hydrous ethanol for use at the internal combustion engines (Otto cycle), of vehicles and of aircrafts, as the utilized in the crop duster Ipanema, is that aimed to this study. The Brazilian Aeronautics Company - Embraer, in partnership with Aircraft Industry Neiva, Ipanema agricultural aircraft manufacturers, converted the engine of this aircraft, originally stocked with aviation gasoline (Avgas) for ethanol in 2005. The success of the conversion of the fossil fuel for the biofuel is proven and reported by aircraft operators throughout Brazil, with advantages environmental, economic, of infrastructure and yield. However, some physical and chemical properties of ethanol as the low lubricity, low flash point, its hygroscopic nature and low viscosity, may bring damage to components of the aircraft fuel system, as well as parts of the engine. Biodiesel possesses features that are useful to the Otto cycle engine, because its organic components associated with your higher electrical conductivity, provide high lubricity when it is added to the ethanol. Biodiesel flash point is high, and thus minimizes flammability risks from transport, storage and supply of ethanol. Because it is less corrosive than ethanol, biodiesel when mixed with ethanol also reduces the conditions of wear and corrosion on parts and engine parts. For diagnosing the ideals levels to the mixture formation were performed eight different compositions (four with soybean biodiesel and four with castor bean biodiesel) varying the percentage of biodiesel at 1%, 3%, 5% and 10% (m/m) in hydrous ethanol. Responses were observed in terms of calorific value, viscosity, flash point, density, electrical conductivity and turbidity for each blend. The calorific value and viscosity were influenced by the major carbon chains of biodiesel, with the largest increase in calorific value occurred in the blend with 10% soybean biodiesel (+ 8.70%). The viscosity of the blend with 10% castor bean biodiesel increased 23.8% and for the blends with 5% castor bean biodiesel and 10% soy biodiesel increased 15%. The flash point for the blends with 10% of soy biodiesel and of castor increased approximately 1 ° C, improving the security conditions in the fuel handling. The density extrapolated the ceiling of specified 1.42% for the blend with 10% castor biodiesel. This parameter is dependent on the amount of water present in the ethanol, which in this study if presented in the maximum, thus doing the density of blends exceed the limit. The electrical conductivity and the turbidity diagnosed homogeneous mixtures, without phase separation and increase in fuel lubricity. / A influência da adição de biodiesel ao etanol hidratado para utilização em motores de combustão interna (ciclo Otto), de veículos e de aeronaves, como o utilizado no avião agrícola Ipanema, é o que objetivou esse estudo. A Empresa Brasileira de Aeronáutica Embraer, em parceria com a Indústria Aeronáutica Neiva, fabricantes do avião agrícola Ipanema, converteu o motor desta aeronave, originalmente abastecido com gasolina de aviação (Avgas), para etanol em 2005. O sucesso da conversão do combustível fóssil para o biocombustível é comprovado e relatado por operadores da aeronave em todo o Brasil, com vantagens ambientais, econômicas, de infraestrutura e rendimento. No entanto, algumas características físicas e químicas do etanol, como sua baixa lubricidade, baixo ponto de fulgor, sua natureza higroscópica e baixa viscosidade, podem trazer danos a componentes do sistema de combustível da aeronave, bem como a partes do motor. O biodiesel possui características que são úteis ao motor ciclo Otto, pois seus componentes orgânicos associados a sua maior condutividade elétrica, proporcionam uma capacidade de lubrificação elevada quando este é adicionado ao etanol. O ponto de fulgor do biodiesel é alto, e assim, minimiza os riscos de inflamabilidade decorrentes do transporte, armazenamento e abastecimento do etanol. Por ser menos corrosivo que o álcool combustível, o biodiesel quando misturado ao etanol também atenua as condições de desgaste e corrosão em peças e partes do motor. Para diagnosticar os teores ideais para formação da mistura, foram realizadas 8 diferentes composições (4 com biodiesel de soja e 4 com biodiesel de mamona), variando-se o percentual de biodiesel em 1%, 3%, 5% e 10% (m/m) em etanol hidratado. As respostas foram verificadas em termos do poder calorífico, da viscosidade, do ponto de fulgor, da densidade, da condutividade elétrica e da turbidez para cada blenda. O poder calorífico e a viscosidade foram influenciados pelas grandes cadeias carbônicas do biodiesel, sendo que o maior acréscimo no poder calorífico ocorreu na blenda com 10% de biodiesel de soja (+ 8,70%). A viscosidade da blenda com 10% de biodiesel de mamona aumentou 23,8% e para as blendas com 5% de biodiesel de mamona e 10% de biodiesel de soja aumentou 15%. O ponto de fulgor para as blendas com 10% de biodiesel de soja e de mamona aumentou aproximadamente 1 °C, melhorando a condição de segurança no manuseio do combustível. A densidade extrapolou o limite máximo da especificação em 1,42% para a blenda com 10% de biodiesel de mamona. Este parâmetro é dependente da quantidade de água presente no etanol, que neste estudo se apresentou no limite máximo, assim, fazendo com que a densidade das blendas ultrapassasse o limite. A condutividade elétrica e a turbidez diagnosticaram misturas homogêneas, sem separação de fases e com acréscimo no poder de lubrificação do combustível

Aeronautical telemetry suffers from multipath interference, which can be resolved through the use of equalizers at the receiver. The coefficients of data-aided equalizers are computed from a channel estimate. Most channels seen in aeronautical telemetry are sparse, meaning that most of the coefficients of the channel are zero or nearly zero. The maximum likelihood (ML) estimate does not always produce a sparse channel estimate. This thesis surveys a number of sparse estimation algorithms that produce a sparse channel estimate and compares the post-equalizer bit error rates (BER) using these sparse estimates with the post-equalizer BER using the ML estimate. I show that the generalized Orthogonal Matching Pursuit (GOMP) performs the best followed by the Sparse Estimation based on Validation Re-estimated Least Squares (SPARSEVA-RE) and the Least Absolute Shrinkage and Selection Operator (LASSO).

The aim of this effort is to implement a nonlinear flight control architecture, specifically flight path control via command filtered backstepping, for use in AME UAS's Fury® 1500 unmanned flying wing aircraft. Backstepping is a recursive, control-effort minimizing, constructive design procedure that interlaces the choice of a Lyapunov function with the design of feedback control. It allows the use of certain plant states to act as intermediate, virtual controls, for others breaking complex high order systems into a sequence of simpler lower-order design tasks. Work herein is a simplified implementation based on publications by Farrell, Sharma, and Polycarpou. Online approximation is not applied, however command filtering along with two variants of control allocation is. This minimal approach was done to mitigate risk, as adaptation could be added in future work to this baseline. Command filtering assures that control inputs generated meet magnitude, rate, and bandwidth constraints for states and actuators as well as provides command derivatives that reduce computation. Two different forms of control allocation were implemented, the simplest a least-squares pseudo-inverse and the second an optimal quadratic programming method. Two Simulink based simulations successfully flew AME's Fury® 1500 UAS: a nominal case with fully operational actuators and a failure case with an actuator stuck at -10°. Coordinated flight for both cases with outer loop tracking was achieved for a demanding autopilot task of simultaneously varying heading and flight-path angle commands, ±60° and ±10° respectively, for a constant airspeed command of 135 ft/s. Command signals were generated were achievable due to the command filter implementation.

Lorsqu’un concepteur de systèmes d’électronique de puissance est engagé dans un processus de pré-design, c’est-à-dire la définition du cahier des charges du système, il doit surmonter plusieurs difficultés. La première étant de trouver grâce à son expérience et à la littérature, toutes les architectures, topologies de conversion et technologies de composants susceptibles de répondre aux besoins du système.A partir de cette éventail, le concepteur doit en éliminer un certain nombre via des arguments qualitatifs ou quantitatifs jusqu’à ce qu’il n’en reste plus qu’un nombre très restreint. Il est primordial pour le concepteur que parmi les choix restant, celui-ci en connaisse les limites de design pour définir avec certitude le plan de développement du produit et les problématiques futures à résoudre. En d’autres termes, il lui faut définir la juste formulation du problème qui lui est posée.Posséder une méthode lui permettant d’atteindre cet objectif en toute confiance et dans les délais impartis est fortement désirable. Ceci est l’objet de cette thèse.Nous proposons donc une nouvelle approche basée sur le pré-dimensionnement par optimisation dans le monde continu (imaginaire) de systèmes d’électronique de puissance. La méthode proposée utilise en effet un algorithme d’optimisation basé sur le calcul du gradient du modèle du système. Cet algorithme permet de gérer un très grand nombre de paramètres de design, autrement dit permet d’explorer un large éventail de solutions dans le monde imaginaire. Il nécessite donc des modèles de systèmes d’électronique de puissance continus et dérivables avec des variables d’optimisation continues (imaginaires) malgré le caractère discret des composants utilisés en électronique.Les présents travaux de thèse ont donc consistés à proposer des modèles d’optimisation continus et dérivables d’un convertisseur Buck entrelacé utilisé dans un aéronef appelé « Stratobus » et à valider ces modèles d’optimisation par une démarche expérimentale sur un prototype complet. Ces modèles ont ensuite été utilisés pour le pré-dimensionnement de ce convertisseur dans le cadre du projet Stratobus permettant dans un premier temps une étude sur le mode de conduction et les matériaux magnétique minimisant la masse du convertisseur, puis une analyse de l’impact de variation de cahier des charges sur la masse du convertisseur. Enfin, les convertisseurs étant construits à partir de composants électroniques choisis sur étagère, une procédure de discrétisation a été mise en place pour revenir au monde réel. / When a designer of power electronics systems is involved in a pre-design process, i.e. the definition of the system specifications, he/she has to overcome several difficulties. The first is to find, based on its experience and literature, all the architectures, conversion topologies and component technologies that can meet the needs of the system.From this list of possibilities, the designer must eliminate a certain number of them via qualitative or quantitative arguments until only a small number remains. It is essential for the designer that he/she knows the design limits of each remaining choices to define with certainty the product development plan and the future design issues to be solved. In other words, it must define the correct problem formulation.Having a method to achieve this objective with confidence and on schedule is highly desirable. This is the purpose of this thesis.We therefore propose a new approach based on preliminary design by optimization in the continuous (imaginary) world of power electronics systems. The proposed method uses an optimization algorithm based on the calculation of the gradient of the system model. This algorithm allows to manage a very large number of design parameters, in other words to explore a wide range of solutions in the imaginary world. It therefore requires continuous and differentiable models of power electronics systems with continuous (imaginary) optimization variables despite the discrete nature of the components used in electronics.The present thesis work has thus consisted in proposing continuous and derivable optimization models of an interleaved Buck converter used in an aircraft called "Stratobus" and validating these optimization models by an experimental approach on a complete prototype. These models have then been used for the pre-dimensioning of this converter as part of the Stratobus project. Firstly a study on the conduction mode and magnetic materials minimizing the mass of the converter has been performed. And then the impact of variation of the specifications on the mass of the converter has been analyzed. Finally, since the converters are built from electronic components chosen off the shelf, a discretization procedure has been set up to return to the real world.

Since the first flights in Sydney in 1910, the problem of exactly where to locate Sydney's airport has preoccupied and troubled planners, politicians and residents of the city. This thesis examines Sydney airport as a space, site and symbol under contestation by major social forces - Zukin - throughout the twentieth century. In doing so, it seeks to question the claims of both planners and anti-airport protestors to resolve and manage large-scale urban developments. Via a series of case studies of representations of the airport, the thesis develops an argument for understanding the airport as a heterotopia: neither sublime nor abject, but through such an extremist spatial imaginary pointing to the production of modernist space as a highly contested process. Because it localises and materialises discourses on the nature and goals of progress,internationalisation and globalisation, it is argued that the built form of the airport is, and will continue to be, a key site of such aerial modernity. The final chapter closely reads a series of airport tales- (a film, a play and a park) in order to consider the ways in which they rework the modernist sublime in domestic space.It is concluded that these stories offer a method of representing locality that goes beyond the existing understandings of locality as an essence of place. The appeal of the narratives lies in the shift that they develop, through excessive and negotiated representations of both the domestic and the sublime, from the local as essence, to locality as practice. / Doctor of Philosophy (PhD)

Various methods have been used, including airborne radars, LIDAR, observation of flying birds, towers, tethered balloons, and aircraft to gain both a qualitative and quantitative representation of how heat and moisture are transported to higher altitudes and grow the boundary or mixing layer by thermal updrafts. This paper builds upon that research using an instrumented glider to determine the structure and build a mathematical model of thermals in a desert environment. During these flights, it was discovered that the traditional view of a thermal as a singular rising plume of air did not sufficiently explain what was being observed, but rather another phenomenon was occurring. This paper puts forth the argument and a mathematical model to show that thermals actually take the form of a hexagonal convection cell at higher levels in the convective boundary layer when the thermal acts as if unrestrained by borders as in non-linear cases of free convection.

The purpose of this study is to investigate the execution and validity of various predictive methods used in the design of the aerodynamic pod housing NASA’s Marshall Airborne Polarimetric Imaging Radiometer (MAPIR) on the University of Tennessee Space Institute’s Piper Navajo research aircraft. Potential flow theory and wing theory are both used to analytically predict the lift the MAPIR Pod would generate during flight; skin friction theory, empirical data, and induced drag theory are utilized to analytically predict the pod’s drag. Furthermore, a simplified computational fluid dynamics (CFD) model was also created to approximate the aerodynamic forces acting on the pod. A limited flight test regime was executed to collect data on the actual aerodynamic effects of the MAPIR Pod. Comparison of the various aerodynamic predictions with the experimental results shows that the assumptions made for the analytic and CFD analyses are too simplistic; as a result, the predictions are not valid. These methods are not proven to be inherently flawed, however, and suggestions for future uses and improvements are thus offered.