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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

FÄLTARBETENS PÅVERKAN PÅ MARKOPERATIONER - EN TEORIPRÖVANDE FALLSTUDIE PÅ SOVJETISKA FÄLTARBETEN UNDER OPERATION BAGRATION

Karlsson, Morgan January 2019 (has links)
Previous research on the art of military engineering indicates that the development of this support branch focuses on technological and organizational advancements whereas theory development seems to be lacking. The purpose of this study is to explore the extent to which J.F.C Fuller´s theory might be able to address the scientific gap that exists today, by considering the possible impact of military engineering on the outcome of a historical land operation. The study uses a case study to examine the four offensives of the Soviet Union’s Operation Bagration, drawing on a theoretical framework derived from contemporary maneuver warfare theory by J.F.C Fuller. This theory contains the physical elements of war: mobility, offensive power and protection and Fuller´s physical principles of war with their tactical and strategical classes. These classes and elements are applied throughout this study to analyze the occurrence of military engineering and their effect on the operation. The findings of the study show that J.F.C Fuller´s theory can be applied to historical offensives to examine the effects military engineering has on the outcome. The effects can for example be explained through the contribution military engineering has on limiting the opponent’s mobility and enabling the envelopment of the opponent’s flanks through mobility.
62

Particle swarm optimization applied to real-time asset allocation

Reynolds, Joshua 05 1900 (has links)
Particle Swam Optimization (PSO) is especially useful for rapid optimization of problems involving multiple objectives and constraints in dynamic environments. It regularly and substantially outperforms other algorithms in benchmark tests. This paper describes research leading to the application of PSO to the autonomous asset management problem in electronic warfare. The PSO speed provides fast optimization of frequency allocations for receivers and jammers in highly complex and dynamic environments. The key contribution is the simultaneous optimization of the frequency allocations, signal priority, signal strength, and the spatial locations of the assets. The fitness function takes into account the assets' locations in 2 dimensions, maximizing their spatial distribution while maintaining allocations based on signal priority and power. The fast speed of the optimization enables rapid responses to changing conditions in these complex signal environments, which can have real-time battlefield impact. Results optimizing receiver frequencies and locations in 2 dimensions have been successful. Current run-times are between 450ms (3 receivers, 30 transmitters) and 1100ms (7 receivers, 50 transmitters) on a single-threaded x86 based PC. Run-times can be substantially decreased by an order of magnitude when smaller swarm populations and smart swarm termination methods are used, however a trade off exists between run-time and repeatability of solutions. The results of the research on the PSO parameters and fitness function for this problem are demonstrated.
63

A formação dos engenheiros militares: Azevedo Fortes, matemática e ensino da engenharia militar no século XVIII em Portugal e no Brasil / The military engineers backgraund: Azevedo Fortes, Mathematics and education of Military Engineering in XVIIIth century in Portugal and in Brazil

Ribeiro, Dulcyene Maria 20 August 2009 (has links)
Este trabalho tem por fim construir uma história, fundamentalmente com base em fontes primárias, da formação dos engenheiros militares na primeira metade do século XVIII em Portugal e no Brasil, no que se refere principalmente aos conteúdos estudados, com destaque para a álgebra. O tema escolhido deriva do trabalho de iniciação científica que posteriormente teve continuidade na dissertação de mestrado intitulada: A Obra Lógica Racional, Geométrica e Analítica (1744) de Manoel de Azevedo Fortes (1660-1749): um estudo das possíveis contribuições para o desenvolvimento educacional luso-brasileiro, orientada pelo professor Sérgio Roberto Nobre e defendida em 2003, no Instituto de Geociências e Ciências Exatas, da UNESP, campus de Rio Claro. Para a presente investigação, foi fundamental a busca em arquivos, indícios e pormenores das fontes. Por isso, todo esse estudo tem como fundamento essa proximidade com as fontes, documentos manuscritos da administração pública da coroa portuguesa e textos caracterizados como notas de aula ou teóricos, ou seja, produção de alunos e professores, impressos ou manuscritos. O contato com as fontes permitiu contribuir para perspectivar o campo econômico, político e cultural do reino português, no tempo estabelecido, nomeadamente no reinado de D. João V. Nesse contexto, estudou-se a atividade profissional de engenheiro militar, as condições de acesso à profissão e o seu enquadramento institucional, as aspirações de ascensão social e as relações com os superiores hierárquicos. Pode-se entender melhor as circunstâncias da formação do engenheiro militar, estudando o quadro dos alunos que frequentaram a Academia Militar de Lisboa e dos professores dessa instituição. Assim, foi possível perspectivar como se teriam dado as Aulas de formação dos engenheiros militares nas capitanias brasileiras, identificando-se os professores e alunos da época. Por fim, apresentam-se alguns textos que serviram à formação dos engenheiros militares desse tempo, especialmente à formação matemática, procurando entender como foram produzidos, as circunstâncias dos seus usos e os conteúdos neles veiculados. / This paper studies the historical construction, based on primary sources, of military engineers background in the first half of XVIIIth century in Portugal and in Brazil, according to the studied contents, focusing on algebra. The chosen subject is based on a scientific work that became a dissertation named as: A Obra: Lógica, Racional, Geométrica e Analítica (1744) of Manoel Fortes de Azevedo (1660-1749): a study of possible contributions for the education development between Portugal and Brazil, advised by professor Sergio Roberto Nobre and presented in 2003, at the Geoscience and Exact Sciences Institut, of UNESP, in Rio Claro. The search in files and details of sources were essential for this research. Therefore, this study looked for those sources, manuscripts of the public administration from portuguese crown as well as notes of lesson or theoretical documents, which mean, the students and professors production, printed papers or manuscripts. The contact with the sources allowed predicting the economic, political and cultural fields from the portuguese kingdom, in that period, during D. João V reign. In this context, military engineer professional activity, conditions of access to the profession and their institutional adequation, social ascension aspiration and their relationship with hierarchic superiors were studied. It was possible to better understand the military engineer backgraund, studying the students and professors who made part of Lisbon Military Academy. So, it was possible to predict how they would have taught the Lessons for the military engineer background in the Brazilian captainships, in order to identify the professors as well as the students who attended the classes. Finally, some texts that were used to prepare the military engineers of that time are presented, mainly the mathematical background, looking for understanding how the circumstances of their uses and their contents were produced.
64

A formação dos engenheiros militares: Azevedo Fortes, matemática e ensino da engenharia militar no século XVIII em Portugal e no Brasil / The military engineers backgraund: Azevedo Fortes, Mathematics and education of Military Engineering in XVIIIth century in Portugal and in Brazil

Dulcyene Maria Ribeiro 20 August 2009 (has links)
Este trabalho tem por fim construir uma história, fundamentalmente com base em fontes primárias, da formação dos engenheiros militares na primeira metade do século XVIII em Portugal e no Brasil, no que se refere principalmente aos conteúdos estudados, com destaque para a álgebra. O tema escolhido deriva do trabalho de iniciação científica que posteriormente teve continuidade na dissertação de mestrado intitulada: A Obra Lógica Racional, Geométrica e Analítica (1744) de Manoel de Azevedo Fortes (1660-1749): um estudo das possíveis contribuições para o desenvolvimento educacional luso-brasileiro, orientada pelo professor Sérgio Roberto Nobre e defendida em 2003, no Instituto de Geociências e Ciências Exatas, da UNESP, campus de Rio Claro. Para a presente investigação, foi fundamental a busca em arquivos, indícios e pormenores das fontes. Por isso, todo esse estudo tem como fundamento essa proximidade com as fontes, documentos manuscritos da administração pública da coroa portuguesa e textos caracterizados como notas de aula ou teóricos, ou seja, produção de alunos e professores, impressos ou manuscritos. O contato com as fontes permitiu contribuir para perspectivar o campo econômico, político e cultural do reino português, no tempo estabelecido, nomeadamente no reinado de D. João V. Nesse contexto, estudou-se a atividade profissional de engenheiro militar, as condições de acesso à profissão e o seu enquadramento institucional, as aspirações de ascensão social e as relações com os superiores hierárquicos. Pode-se entender melhor as circunstâncias da formação do engenheiro militar, estudando o quadro dos alunos que frequentaram a Academia Militar de Lisboa e dos professores dessa instituição. Assim, foi possível perspectivar como se teriam dado as Aulas de formação dos engenheiros militares nas capitanias brasileiras, identificando-se os professores e alunos da época. Por fim, apresentam-se alguns textos que serviram à formação dos engenheiros militares desse tempo, especialmente à formação matemática, procurando entender como foram produzidos, as circunstâncias dos seus usos e os conteúdos neles veiculados. / This paper studies the historical construction, based on primary sources, of military engineers background in the first half of XVIIIth century in Portugal and in Brazil, according to the studied contents, focusing on algebra. The chosen subject is based on a scientific work that became a dissertation named as: A Obra: Lógica, Racional, Geométrica e Analítica (1744) of Manoel Fortes de Azevedo (1660-1749): a study of possible contributions for the education development between Portugal and Brazil, advised by professor Sergio Roberto Nobre and presented in 2003, at the Geoscience and Exact Sciences Institut, of UNESP, in Rio Claro. The search in files and details of sources were essential for this research. Therefore, this study looked for those sources, manuscripts of the public administration from portuguese crown as well as notes of lesson or theoretical documents, which mean, the students and professors production, printed papers or manuscripts. The contact with the sources allowed predicting the economic, political and cultural fields from the portuguese kingdom, in that period, during D. João V reign. In this context, military engineer professional activity, conditions of access to the profession and their institutional adequation, social ascension aspiration and their relationship with hierarchic superiors were studied. It was possible to better understand the military engineer backgraund, studying the students and professors who made part of Lisbon Military Academy. So, it was possible to predict how they would have taught the Lessons for the military engineer background in the Brazilian captainships, in order to identify the professors as well as the students who attended the classes. Finally, some texts that were used to prepare the military engineers of that time are presented, mainly the mathematical background, looking for understanding how the circumstances of their uses and their contents were produced.
65

Guidance Laws For Impact Angle Constraints And Exo-Atmospheric Engagements

Ratnoo, Ashwini 02 1900 (has links)
This thesis deals with development of guidance laws for advanced applications. Two class of guidance problems, namely, impact angle constrained guidance and pulsed guidance for exo-atmospheric engagements, are considered here. Three impact angle constrained guidance schemes are developed using (i) Proportional navigation guidance (PNG), (ii) State Dependent Riccati Equation (SDRE) technique and (iii) geometric concepts, respectively. A collision course based pulsed guidance law is presented for exo-atmospheric interceptors. Proportional Navigation Guidance (PNG) law is the most widely used guidance law because of its ease of implementation and efficiency. However, in its original form, it achieves only a limited set of impact angles. A two stage PNG law is presented for achieving all impact angles against a stationary target. In the first phase of guidance, an orientation PNG command is used. The orientation navigation constant (N ) is a function of the initial engagement geometry and has a lower value (N less than 2). It is proved that following the orientation trajectory, the interceptor can switch to N = 2 and achieve the desired impact angle. Simulations, with a constant speed and with a realistic interceptor model, show successful interception of the target with all desired impact angles. Feedback implementation of the guidance law results in negligible errors in impact angle with uncompensated autopilot delays. The idea of a two-stage PNG law with impact angle constraint is further used to develop a guidance law for intercepting moving targets. Following the orientation trajectory, the interceptor can switch to N = 3 and achieve the desired impact angle. It is proved that the guidance achieves all impact angles in a surface-to-surface engagement scenario with receding and approaching targets, respectively. In a air-to-surface engagement scenario, it is proved that the guidance law achieves all impact angles in a deterministic set. Constant speed and realistic interceptor models are used for simulations. Results show negligible error in impact angle and miss distance for moving targets. The guidance law, in its feedback implementation form, achieves the desired impact angle for interceptors with delay and with a maneuvering target. The impact angle errors are low with negligible errors in miss distance. Next, the impact angle constrained guidance problem against a stationary target is solved as a non-linear regulator problem using the SDRE technique. The interceptor guidance problems are of finite time nature. As the main contribution of this part of the work, we solve a finite time interceptor guidance problem with infinite horizon SDRE formulation by choosing the state weighting matrix as a function of time-to-go. Numerical simulations are carried out both for a constant speed interceptor model and a realistic interceptor model. Simulations for both the models are carried out for various impact angles and firing angles. Robustness of the proposed guidance law with respect to autopilot lag is also verified by simulations. Results obtained show the efficiency of the SDRE approach for impact angle constrained missile guidance. A geometric guidance scheme is proposed for lateral interception of targets in a planar engagement scenario in the absence of line-of-sight rate information. A kill-band is defined for target initial positions capturable by an arc maneuver, followed by a straight line path by the interceptor. Guidance law for capturing targets inside the kill-band is presented and is further modified for targets outside the kill-band. Based on analytical studies on the kill-band, a guidance law is proposed for lateral interception of maneuvering targets. Simulations are carried with for typical low speed engagements. The concept of kill-band provides an inherent robustness to the proposed guidance law with respect to uncompensated system delays and target maneuver. As the final part of the work, an interceptor endgame pulsed guidance law for exoatmospheric engagements is derived by using the notion of collision heading. The proposed guidance law is derived in steps by (i) Obtaining the collision heading based on the collision triangle engagement geometry and then (ii) Computing the width of the pulse fired by the divert thruster to attain the collision heading. It is shown that this strategy is more effective than the existing zero effort miss (ZEM) based guidance laws for intercepting targets with higher heading angles off the nominal head-on collision course. A result on pulse firing sequence is also presented showing that firing pulses in quick succession results in minimum pulse widths and hence minimum control effort for a desired miss distance. Simulations are carried out for various engagement scenarios. Results show better miss-distance and divert thrust performance as compared to the existing ZEM based law.
66

A Unified, Configurable, Non-Iterative Guidance System For Launch Vehicles

Rajeev, U P 12 1900 (has links)
A satellite launch vehicle not subjected to any perturbations, external or internal, could be guided along a trajectory by following a stored, pre-computed steering program. In practice, perturbations do occur, and in order to take account of them and to achieve an accurate injection, a closed loop guidance system is required. Guidance algorithm is developed by solving the optimal control problem. Closed form solution is difficult because the necessary conditions are in the form of Two Point Boundary Value Problems (TBVP) or Multi Point Boundary Value Problems (MPBVP). Development of non-iterative guidance algorithm is taken as a prime objective of this thesis to ensure reliable on-board implementation. If non-iterative algorithms are required, the usual practice is to approximate the system equations to derive closed form solutions. In the present work, approximations cannot be used because the algorithm has to cater to a wide variety of vehicles and missions. Present development adopts an alternate approach by splitting the reconfigurable algorithm development in to smaller sub-problems such that each sub-problem has closed form solution. The splitting is done in such a way that the solution of the sub-problems can be used as building blocks to construct the final solution. By adding or removing the building blocks, the algorithm can be configured to suit specific requirements. Chapter 1 discusses the motivation and objectives of the thesis and gives a literature survey. In chapter 2, Classical Flat Earth (CFE) guidance algorithm is discussed. The assumptions and the nature of solution are closely analyzed because CFE guidance is used as the baseline for further developments. New contribution in chapter 2 is the extension of CFE guidance for a generalized propulsion system in which liquid and solid engines are present. In chapter 3, CFE guidance is applied for a mission with large pitch steering angles. The result shows loss of optimality and performance. An algorithm based on regular perturbation is developed to compensate for the small angle approximation. The new contribution in chapter 3 is the development of Regular Perturbation based FE (RPFE) guidance as an extension of CFE guidance. RPFE guidance can be configured as CFE guidance and FEGP. Algorithms presented up to chapter 3 are developed to inject a satellite in to orbits with unspecified inertial orientation. Communication satellite missions demand injection in to an orbit with a specific inertial orientation defined by argument of perigee. This problem is formulated using Calculus of Variations in chapter 4. A non-iterative closed form solution (Predicted target Flat Earth or PFE guidance) is derived for this problem. In chapter 5, PFE guidance is extended to a multi-stage vehicle with a constraint on the impact point of spent lower stage. Since the problem is not analytically solvable, the original problem is split in to three sub-problems and solved. Chapter 6 has two parts. First part gives theoretical analysis of the sub-optimal strategies with special emphasis to guidance. Behavior of predicted terminal error and control commands in presence of plant approximations are theoretically analyzed for a class of optimal control problems and the results are presented as six theorems. Chapter 7 presents the conclusions and future works.
67

An Anti-Skid Brake Controller For A Fighter Aircraft With An Elastic Strut

Kumar, V V Nagendra 04 1900 (has links)
This thesis deals with the design of an anti-skid brake controller for a generic fighter aircraft. Antiskid brake controllers prevent wheel locking and maximize the coefficient of friction between the tyre and the ground, resulting in lower stopping distance and time. The frictional force is maximized by regulating the slip. A model for the landing gear is first developed, which consists of the translational and rotational motions of the wheel, the equation for the slip and the elastic landing gear strut dynamics. The elastic behaviour of the landing gear is characterized through its modal frequencies, obtained from a Finite element analysis. As the governing equations are nonlinear, with linear elastic deformations of the strut, feedback linearization is used to design the anti-skid controller. The brake controller is found to work well. Its stability is verified through numerical simulations. Both the plant parameters and the sensor measurements are perturbed up to 10% from their nominal values. It is seen that the feedback linearization tolerates these variations quite well. The system is exceptionally tolerant to sensor noises. The torsional stiffness of the strut is found to be more critical than the longitudinal stiffness. Limits on the torsional stiffness that can be tolerated by the controller are found. This determines the limits on the stiffness of the landing gear beyond which gear walk may appear. The thesis concludes with suggestions for future work in this exciting field.
68

Uma história institucional do Centro Tecnológico do Exército (1979-2013)

Queiroz, Claudete Fernandes de 31 March 2015 (has links)
Submitted by Marcia Bacha (marcia.bacha@fgv.br) on 2015-04-28T14:03:49Z No. of bitstreams: 1 dissertação_claudete.pdf: 757766 bytes, checksum: 13712c9b31a183e5c647c03c9cc17187 (MD5) / Approved for entry into archive by Rafael Aguiar (rafael.aguiar@fgv.br) on 2015-05-04T20:00:14Z (GMT) No. of bitstreams: 1 dissertação_claudete.pdf: 757766 bytes, checksum: 13712c9b31a183e5c647c03c9cc17187 (MD5) / Approved for entry into archive by Marcia Bacha (marcia.bacha@fgv.br) on 2015-05-05T12:07:52Z (GMT) No. of bitstreams: 1 dissertação_claudete.pdf: 757766 bytes, checksum: 13712c9b31a183e5c647c03c9cc17187 (MD5) / Made available in DSpace on 2015-05-05T12:08:08Z (GMT). No. of bitstreams: 1 dissertação_claudete.pdf: 757766 bytes, checksum: 13712c9b31a183e5c647c03c9cc17187 (MD5) Previous issue date: 2015-03-31 / Este trabalho narra a história da criação e do desenvolvimento institucional do Centro Tecnológico do Exército (CTEx), órgão voltado para a pesquisa e o desenvolvimento dos materiais de emprego militar do Exército Brasileiro. A pesquisa teve como objetivo principal analisar a origem da instituição, os motivos para a sua criação e o papel dos principais atores envolvidos, além de apresentar os principais projetos desenvolvidos no CTEx. Inicialmente, analisa-se a área de Ciência e Tecnologia no Brasil entre os anos de 1960 a 1980, e em seguida aprofundam-se os aspectos fundamentais da história do CTEx entre 1979 e 2013. Por fim, são apresentados os resultados obtidos nas entrevistas realizadas com 26 (vinte e seis) servidores (militares e civis) que atuam principalmente nas áreas de pesquisa e desenvolvimento no CTEx. / This work tells the story of the creation and the institutional development of the Army Technology Center (CTEx), dedicated to the research and development on military use of materials in the Brazilian Army. The aim of this study is to analyze the origin of this institution, the reasons for its creation and the role of the main actors involved, as well as present the main projects developed in CTEx. Initially, we analyze the field of Science and Technology in Brazil between 1960 and 1980, and then deepen fundamental aspects of the history of CTEx between 1979 and 2013. Finally, one presents the results obtained from interviews with 26 (twenty-six) servers (military and civilian) working mainly with research and development in CTEx

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