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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.
151

Método de avaliação de segurança crítica para a integração de veículos aéreos não tripulados no espaço aéreo controlado e não segregado. / Safety assessment method for the unmanned aerial vehicles integration in controlled and non-segregated airspace.

Ricardo Alexandre Veiga Gimenes 19 June 2015 (has links)
A crescente demanda por Veículos Aéreos Não Tripulados (VANT) tem sido objeto de preocupação por parte das organizações internacionais responsáveis pela segurança do espaço aéreo. O uso de VANT em condições restritas tem sido realizado pelos interessados e envolvidos, mas para que o VANT seja economicamente viável, há a necessidade de regulamentação ainda não existente para sua integração segura no Espaço Aéreo Controlado e Não Segregado. Em função dessa demanda não atendida, nesta Tese foi desenvolvido um método (Safety-VANT) que avalia a segurança crítica da condução do VANT, tarefa realizada por um Sistema Autônomo de Pilotagem. O desenvolvimento do Método Safety-VANT tem como missão fornecer aos órgãos reguladores, assim como aos desenvolvedores de VANT, meios de quantificar a avaliação de segurança na navegabilidade aérea dessas aeronaves. Uma hipótese considerada para o método é a de que o hardware e software (aviônicos, fuselagem, sensores e atuadores) do VANT estejam previamente avaliados e certificados pelos mesmos procedimentos e regras aplicáveis para os equipamentos de aeronaves tripuladas. Essa hipótese permitiu que o desenvolvimento do método de avaliação de segurança Safety-VANT fosse direcionado para avaliar a capacidade de comando autônomo de um VANT para voar, navegar e comunicar de acordo com as regras do sistema de gerenciamento e controle do tráfego aéreo. A aplicação do Safety-VANT foi exercitada sob um VANT hipotético definido como sendo capaz de voar, navegar e se comunicar com o Controle de Tráfego Aéreo e que tenha os equipamentos e estrutura da aeronave (fuselagem) que o constitui, devidamente certificados. Adicionalmente são realizadas considerações sobre como implantar a utilização do Safety-VANT no desenvolvimento de VANT Autônomo com a missão de ser integrado no Espaço Aéreo. / The growing demand for unmanned aerial vehicles (UAV) has been a subject of concern on the part of international organizations responsible for airspace safety. UAV has been used by stakeholders in strict conditions, but for UAV to become economically viable, it is necessary to issue regulations that still do not exist for safe integration in the controlled non-segregated airspace. In the light of this unattended demand, a method (Safety-VANT) was developed in this Thesis to evaluate the critical safety of UAV conduction, a task performed by a Piloting Autonomous System. The development of the Safety-VANT method aims to provide UAV regulators and developers, means of quantifying the safety assessment in the aircraft airworthiness. A hypothesis used in the method considers that the UAV hardware and software (avionics, fairing, sensors and actuators) are previously evaluated and certified by the same procedures and rules applicable to manned aircraft equipment. This hypothesis allowed the Safety-VANT - the developed safety assessment method - to evaluate the ability of an autonomous command embedded in an UAV to fly, to navigate and to communicate, according to the management of air navigation system rules. The Safety-VANT application was exercised under a hypothetical UAV set to being able to fly, to navigate and to communicate with Air Traffic Control and it has the equipment and the certified aircraft structure (fairing). In addition, considerations are performed for deploying the use of Safety-VANT in autonomous UAV development to integrate it into the Airspace.
152

Vision-Based Emergency Landing of Small Unmanned Aircraft Systems

Lusk, Parker Chase 01 November 2018 (has links)
Emergency landing is a critical safety mechanism for aerial vehicles. Commercial aircraft have triply-redundant systems that greatly increase the probability that the pilot will be able to land the aircraft at a designated airfield in the event of an emergency. In general aviation, the chances of always reaching a designated airfield are lower, but the successful pilot might use landmarks and other visual information to safely land in unprepared locations. For small unmanned aircraft systems (sUAS), triply- or even doubly-redundant systems are unlikely due to size, weight, and power constraints. Additionally, there is a growing demand for beyond visual line of sight (BVLOS) operations, where an sUAS operator would be unable to guide the vehicle safely to the ground. This thesis presents a machine vision-based approach to emergency landing for small unmanned aircraft systems. In the event of an emergency, the vehicle uses a pre-compiled database of potential landing sites to select the most accessible location to land based on vehicle health. Because it is impossible to know the current state of any ground environment, a camera is used for real-time visual feedback. Using the recently developed Recursive-RANSAC algorithm, an arbitrary number of moving ground obstacles can be visually detected and tracked. If obstacles are present in the selected ditch site, the emergency landing system chooses a new ditch site to mitigate risk. This system is called Safe2Ditch.
153

Integration and assessment of a dual core chip - Atmel’s DIOPSIS 940 - for a flight control system.

Majewski, Łukasz January 2009 (has links)
<p>A dual core Atmel DIOPSIS 940 chip consists of a DSP and an ARM9 functional units in a single silicon die. This thesis presents the process of integration and assessment of using this processor in a flight control system. A complete design of the system is provided including a description of the DIOPSIS 940 from the perspective of requirements of the application. The integration of the processor with a typical set of components of a flight control system is provided. Additionally, a suite of programs required for developing software for the system is included. Capabilities of both cores of the processor are analysed in a series of experiments. Computational performance in typical tasks of a flight control system is analyzed and compared. The application of attitude stabilization for a micro-scale UAS is described.</p>
154

Mission Specialist Human-Robot Interaction in Micro Unmanned Aerial Systems

Peschel, Joshua Michael 2012 August 1900 (has links)
This research investigated the Mission Specialist role in micro unmanned aerial systems (mUAS) and was informed by human-robot interaction (HRI) and technology findings, resulting in the design of an interface that increased the individual performance of 26 untrained CBRN (chemical, biological, radiological, nuclear) responders during two field studies, and yielded formative observations for HRI in mUAS. Findings from the HRI literature suggested a Mission Specialist requires a role-specific interface that shares visual common ground with the Pilot role and allows active control of the unmanned aerial vehicle (UAV) payload camera. Current interaction technology prohibits this as responders view the same interface as the Pilot and give verbal directions for navigation and payload control. A review of interaction principles resulted in a synthesis of five design guidelines and a system architecture that were used to implement a Mission Specialist interface on an Apple iPad. The Shared Roles Model was used to model the mUAS human-robot team using three formal role descriptions synthesized from the literature (Flight Director, Pilot, and Mission Specialist). The Mission Specialist interface was evaluated through two separate field studies involving 26 CBRN experts who did not have mUAS experience. The studies consisted of 52 mission trials to surveil, evaluate, and capture imagery of a chemical train derailment incident staged at Disaster City. Results from the experimental study showed that when a Mission Specialist was able to actively control the UAV payload camera and verbally coordinate with the Pilot, greater role empowerment (confidence, comfort, and perceived best individual and team performance) was reported by a majority of participants for similar tasks; thus, a role-specific interface is preferred and should be used by untrained responders instead of viewing the same interface as the Pilot in mUAS. Formative observations made during this research suggested: i) establishing common ground in mUAS is both verbal and visual, ii) type of coordination (active or passive) preferred by the Mission Specialist is affected by command-level experience and perceived responsibility for the robot, and iii) a separate Pilot role is necessary regardless of preferred coordination type in mUAS. This research is of importance to HRI and CBRN researchers and practitioners, as well as those in the fields of robotics, human-computer interaction, and artificial intelligence, because it found that a human Pilot role is necessary for assistance and understanding, and that there are hidden dependencies in the human-robot team that affect Mission Specialist performance.
155

旋翼UAS影像密匹配建物點雲自動分群之研究 / Automatic clustering of building point clouds from dense matching VTOL UAS images

林柔安, Lin, Jou An Unknown Date (has links)
三維城市模型之建置需求漸趨繁多,可提供都市規劃、城市導航及虛擬實境等相關應用,過去研究多以建置LOD2城市模型為主,且較著重於屋頂結構。近年來,逐漸利用垂直影像及傾斜影像作為原始資料,提供建物牆面之建置,並且,隨著無人機系統(Unmanned Aircraft System, UAS)發展,可利用其蒐集高解析度且高重疊垂直及傾斜拍攝之建物影像,並採影像密匹配技術產製高密度點雲,進而快速取得建物包含屋頂及牆面之三維資訊,而這些資訊可進一步提供後續建置LOD3建置層級之模型,而在建置前,首先須對資料進行特徵分析,萃取特徵點、線、面,進而提供建置模型所需之資訊。 因此,本研究期望利用密匹配點雲,計算其點雲特徵,並採用Mean Shift分群法(Comaniciu and Meer, 2002)萃取建物點雲資訊,並提供一最佳分群策略。首先,本研究將以UAS為載具,設計一野外率定場率定相機,並蒐集建物高重疊UAS影像密匹配產製高密度點雲,針對單棟建物高密度點雲,實驗測試點雲疏化程度後,依據疏化成果計算點雲特徵,並以此批點雲資料實驗測試Mean shift分群法(Cheng, 1995)中之參數,後設計分群流程以分離平面點群及曲面點群,探討分群成果以決定最佳分群策略。實驗結果顯示本研究提出之分群策略,可自動區分平面點群及曲面點群,並單獨將平面點群分群至各牆面。 / Unmanned Aerial System (UAS) offer several new possibilities in a wide range of applications. One example is the 3D reconstruction of buildings. In former times this was either restricted by earthbound vehicles to the reconstruction of facades or by air-borne sensors to generate only very coarse building models. UAS are able to observe the whole 3D scene and to capture images of the object of interest from completely different perspectives. Therefore, this study will use UAS to collected images of buildings and to generate point cloud from dense image matching for modeling buildings. In the proposed approach, this method computes principal orientations by PCA and identifies clusters by Mean shift clustering. Analyze the factors which can affect the clustering methods and try to decrease the use of threshold, and this result can cluster the façade of buildings automatically and offer the after building reconstruction for LOD3.
156

Self-configuring ad-hoc networks for unmanned aerial systems

Christmann, Hans Claus 01 April 2008 (has links)
Currently there is ongoing research in the field of Mobile Ad-hoc Networks (MANET) for several different scenarios. Research has focused on topology related challenges such as routing mechanisms or addressing systems, as well as security issues like traceability of radio communication or encryption. In addition, there are very specific research interests such as the effects of directional antennas for MANETs or optimized transmission techniques for minimal power consumption or range optimization. Unmanned aerial vehicles (UAVs), and unmanned aerial systems (UAS) in general, need wireless systems in order to communicate. Current UAS are very flexible and allow for a wide spectrum of mission profiles by means of utilizing different UAVs, according to the requirements at hand. Each mission poses special needs and requirements on the internal and external UAS communication and special mission scenarios calling for UAV swarms increase the complexity and require specialized communication solutions. UAS have specific needs not provided by the general research, but are, on the other hand, to diversified to make much use of narrowly focused developments; UAS form a sufficiently large research area for application of MANETs to be considered as an independent group with specialized needs worthy of tailored implementations of MANET principles. MANET research has not tackled a general approach to UAS although some sources show specific applications involving UAVS. This work presents some new aspects for the development of of ad-hoc wireless networks for UAVs and UAS and focuses on their specialties and needs. A general framework for MANET development is proposed. Furthermore, the proposed specific evaluation scenarios provide for a UAS focused comparison of MANET performance.
157

Investigando as políticas de assistência e proteção à infância : psicologia e ações do Estado / Investication about the infancy assistance and protection policies in Brazil

Irene Bulcão 12 March 2006 (has links)
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Esta tese consiste em uma investigação bibliográfica e documental sobre as políticas de assistência e proteção à infância no Brasil. Com relação a esta questão, pesquisei fios de nossa história desde o período colonial até o final da chamada Era Vargas. Inicio este percurso histórico num momento em que o abandono de crianças não era considerado um problema, e funcionavam engrenagens de proteção por proximidade; caminho até os anos de 1930, quando médicos e juristas se mobilizam no sentido de organizar a assistência e a proteção ao menor de idade, contribuindo para a criação de outros modelos de atendimento à infância, baseados na assistência social e na proteção de Estado. Neste ponto, faço uma breve análise da chegada de Getúlio Vargas ao governo e de sua permanência nele até 1945. Em seguida discuto as mudanças ocorridas na estrutura das relações entre capital e trabalho na sociedade capitalista européia, quando o social se configurou enquanto um novo domínio de saber que possibilitou a emergência dos chamados profissionais do social, apontando similaridades com o processo ocorrido no Brasil durante a Era Vargas. A análise se foca, então, nos movimentos de criação e implementação de ações específicas para tratar da criança dita desassistida durante o Estado Novo, implementadas a partir do funcionamento de dois órgãos: o Departamento Nacional da Criança (DNCr) criado em 1940 para coordenar todas as atividades relativas a proteção à maternidade, à infância e à adolescência e o Serviço de Assistência a Menores (S.A.M.) criado em 1941 para superintender todo o serviço de amparo a menores desvalidos e delinqüentes, buscando sempre identificar que noções de psicologia que se faziam aí presentes. À guisa de conclusão, compartilho descobertas, encontros e desencontros proporcionados pela realização deste trabalho. / This thesis consists of a bibliographical and documental investigation about the infancy assistance and protection policies in Brazil. Related to this question, I researched historical lines since the colonial period up to the end of the so called Vargas Era. I start this historical course at the moment in which the children abandonment was not considered as a problem, and mechanisms worked as protection by proximity; I go back to the 1930s, when physicians and jurists mobilize themselves towards the underaged assistance and protection organization, which contributed to the creation of other attendance models, based on social assistance and on the State protection. At his point I make a concise analysis of Getúlio Vargas arrival at government and of his stay as president until 1945. Following this, I discuss the ocurred changes in the relationship structures between capital and work in the capitalist european society, when the social was configured as a new knowledge domain which allowed the emergence of the so caleed social professionals, pointing to similarities with the ocurred process in Brazil during the Vargas Era. Then, the analysis focuses itself in the creation and implementation movements of specific actions to treat the called not assisted child during the New State, implemented from the operation of two organs: the National Child Department (NCD) created in 1940 to coordinate all activities related to the protection of motherhood, infancy and adolescence and the Underaged Assistance Servic (UAS) created in 1941 to superintend all the services to assist unprotected underaged and delinquents , always searching to identify which psychology conceptions were present in both of them. As Conclusion, I share the foundings, encounters and discordances allowed by the realization of this work.
158

Contributions au vol en formation serrée de petits drones / Contributions to Tight Formation Flight Control of Small UAS

Bolting, Jan 26 September 2017 (has links)
Les mini-drones à propulsion électrique sont susceptibles d’avoir une endurance inférieure à celle de drones plus grands.L’exploitation des interactions aérodynamiques, inspirée par les oiseaux migratoires, ainsi que le ravitaillement en vol , sont des approches prometteuses pour améliorer l’endurance des mini-drones. La commande par modes glissants d’ordre supérieur en temps continu (CTHOSM) a été considérée comme un candidat prometteur à ce problème ouvert difficile et a été appliquée avec succès à des modèles cinématiques simples. Dans nos travaux, nous étudions les implications de la présence de la dynamique de la boucle interne et de l’implémentation en temps discret à des taux d’échantillonnage modérés et constatons alors que l’application de la commande CTHOSM devient impossible. Nous proposons donc un schéma de guidage prédictif discret par modes glissants pour approximer les performances de la commande CTHOSM pour une dynamique réaliste du drone. On propose également un problème de référence accessible pour d'autres chercheurs. Les algorithmes de localisation probabilistes existants ne permettent pas la caractérisation de régions de confiance garanties de la position des autres membres de la formation. Dans ce contexte, nous proposons un nouveau filtre ensembliste caractérisant de telles régions de confiance sous forme ellipsoïdale. Nos premières évaluations ont montré que les efforts de calcul induits par cette mise en œuvre restent parfaitement compatibles avec les contraintes des systèmes avioniques des petits drones. / Small, electrically driven unmanned aircraft are likely to suffer from inferior endurance compared to their larger counterparts. Upwash exploitation by tight formation flight, as well as aerial recharging are the most promising control-driven approaches to mitigate this disadvantage. Continuous time higher order sliding mode control (CTHOSM) has been considered as a candidate for this challenging open problem and was successfully applied to simple kinematic models in simulation, where excellent relative position tracking performance can be demonstrated. In this work we study the implications of the presence of inner loop dynamics and discrete implementation at moderate sampling rates and we find that it precludes the application of CTHOSM control to fixed-wing UAS. We propose a predictive discrete sliding mode guidance scheme to approximate the performance of CTHOSM control assuming realistic fixed-wing UAS dynamics. We show that the proposed guidance scheme in combination with inner load factor tracking loops and a disturbance observer allows for relative position tracking performance compatible with the requirements of upwash exploitation. We propose as well an openly accessible benchmark problem. Existing probabilistic localization algorithms cannot provide guaranteed confidence regions of the relative position between UAS. We present a set membership filter that provides ellipsoidal regions guaranteed to contain the relative positions of the other UAS. It is compatible with the hardware constraints of small low-cost UAS. Simulations suggest computational efforts compatible with the computational resources typically available onboard small UAS.
159

Developmental and Functional Roles of Troponin-T Isoforms, and Exploring Genome-Wide Alterations in Drosophila Indirect Flight Muscle Mutants

Madan, Aditi January 2015 (has links) (PDF)
Muscle contraction is a highly fine-tuned process that requires the precise and timely construction of large protein sub-assemblies to form sarcomeres, the individual contractile units. Mutations in many of the genes encoding constituent proteins of this macromolecular machine result in defective functioning of the muscle tissue, and in humans, often lead to myopathic conditions like cardiomyopathies and muscular dystrophies, which affect a considerable number of people the world over. As more information regarding causative mutations becomes available, it becomes imperative to explore mechanisms of muscle development, maintenance and pathology. In striated muscles, contraction is regulated by the thin filament-specific tropomyosin (Tm) – troponin (Tn) complex (Ca2+-binding troponin-C, inhibitory troponin-I and tropomyosin-binding troponin-T). These troponin subunits are present in 1:1:1 ratio on thin filaments, with 1 Tm-Tn complex present on every 7th actin molecule. This stoichiometry is tightly regulated, and disturbances have been associated with functional defects. Each of these proteins has multiple isoforms, whose expression is controlled both spatially and temporally. The expression of specific combination of isoforms confers specific contractile properties to each muscle subtype. Drosophila melanogaster has been a preferred model of choice to study various aspects of muscle development for decades. In this study, the Indirect Flight Muscles (IFMs) of Drosophila have been used to investigate developmental and functional roles of two temporally regulated isoforms of a vital structural and regulatory component of the sarcomere – Troponin T (TnT). On a larger scale, whole genome expression profiles of mutants that are null for major myofbrillar proteins have also been discussed. IFMs serve as an excellent model system to address these questions, owing to the extreme ease of genetic manipulability in this system, and high degree of homology between mammalian and Dipteran cytoskeletal proteins. Chapter 1 covers basics of muscle biology, and the role of TnT in muscle contraction. Phenomena responsible for generating diversity in genes encoding muscle proteins – alternative splicing and isoform switching – have also been discussed. These mechanisms are highly conserved, as are patterns of TnT splicing and isoform expression across phyla. Mutations leading to altered splicing patterns lead to myopathic conditions, and the importance of model systems to study muscle biology has been emphasized. The advantages of studying Drosophila IFMs and a comprehensive overview of IFM development has been covered. The resources and experimental tools used have been described in Chapter 2. Two isoforms of TnT are alternatively spliced in the Drosophila thorax – one containing alternative exon 10a (expressed in adult IFMs and jump muscle); and one containing alternative exon 10b (expressed in pupae and newly eclosed flies). These exons are spliced in a mutually exclusive manner, and defects in splicing have been reported to cause uncontrolled, auto-destructive contractions. In Chapter 3, a splice mutant of TnT, up1, has been discussed, with respect to its developmental profile. Transgenic rescue experiments with two separate isoforms demonstrate rescue at the structural as well as functional level. Transgenic over-expression, however, leads to functional abnormalities, highlighting the importance of stoichiometry in multi-protein complexes. In Chapter 4, molecular signals that bring about the developmentally regulated TnT isoform switch are discussed. A splicing factor, Muscleblind, has been transgenically knocked down in normal and mutant IFMs to study effects on muscle function. Chapter 5 looks at whole genome transcriptional alterations in muscles null for either actin or myosin. All significant expression changes have been classified into categories based on different biological processes, and an attempt to differentiate generic muscle responses from filament-specific responses has been made. In conclusion, the studies have highlighted the importance of TnT isoform switching, and that extended expression of a pupal stage-specific isoform can partially compensate for loss of the adult isoform. Also, in the absence of major myofibrillar proteins, stress response pathways like heat shock response and protein degradation pathways are activated, along with a subset of metabolic responses that are unique to the thin or thick filament systems.
160

Investigando as políticas de assistência e proteção à infância : psicologia e ações do Estado / Investication about the infancy assistance and protection policies in Brazil

Irene Bulcão 12 March 2006 (has links)
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Esta tese consiste em uma investigação bibliográfica e documental sobre as políticas de assistência e proteção à infância no Brasil. Com relação a esta questão, pesquisei fios de nossa história desde o período colonial até o final da chamada Era Vargas. Inicio este percurso histórico num momento em que o abandono de crianças não era considerado um problema, e funcionavam engrenagens de proteção por proximidade; caminho até os anos de 1930, quando médicos e juristas se mobilizam no sentido de organizar a assistência e a proteção ao menor de idade, contribuindo para a criação de outros modelos de atendimento à infância, baseados na assistência social e na proteção de Estado. Neste ponto, faço uma breve análise da chegada de Getúlio Vargas ao governo e de sua permanência nele até 1945. Em seguida discuto as mudanças ocorridas na estrutura das relações entre capital e trabalho na sociedade capitalista européia, quando o social se configurou enquanto um novo domínio de saber que possibilitou a emergência dos chamados profissionais do social, apontando similaridades com o processo ocorrido no Brasil durante a Era Vargas. A análise se foca, então, nos movimentos de criação e implementação de ações específicas para tratar da criança dita desassistida durante o Estado Novo, implementadas a partir do funcionamento de dois órgãos: o Departamento Nacional da Criança (DNCr) criado em 1940 para coordenar todas as atividades relativas a proteção à maternidade, à infância e à adolescência e o Serviço de Assistência a Menores (S.A.M.) criado em 1941 para superintender todo o serviço de amparo a menores desvalidos e delinqüentes, buscando sempre identificar que noções de psicologia que se faziam aí presentes. À guisa de conclusão, compartilho descobertas, encontros e desencontros proporcionados pela realização deste trabalho. / This thesis consists of a bibliographical and documental investigation about the infancy assistance and protection policies in Brazil. Related to this question, I researched historical lines since the colonial period up to the end of the so called Vargas Era. I start this historical course at the moment in which the children abandonment was not considered as a problem, and mechanisms worked as protection by proximity; I go back to the 1930s, when physicians and jurists mobilize themselves towards the underaged assistance and protection organization, which contributed to the creation of other attendance models, based on social assistance and on the State protection. At his point I make a concise analysis of Getúlio Vargas arrival at government and of his stay as president until 1945. Following this, I discuss the ocurred changes in the relationship structures between capital and work in the capitalist european society, when the social was configured as a new knowledge domain which allowed the emergence of the so caleed social professionals, pointing to similarities with the ocurred process in Brazil during the Vargas Era. Then, the analysis focuses itself in the creation and implementation movements of specific actions to treat the called not assisted child during the New State, implemented from the operation of two organs: the National Child Department (NCD) created in 1940 to coordinate all activities related to the protection of motherhood, infancy and adolescence and the Underaged Assistance Servic (UAS) created in 1941 to superintend all the services to assist unprotected underaged and delinquents , always searching to identify which psychology conceptions were present in both of them. As Conclusion, I share the foundings, encounters and discordances allowed by the realization of this work.

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