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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.
1

LADAR: A Mono-static System for Sense and Avoid Applications

Bradley, Cullen Philip 23 May 2013 (has links)
No description available.
2

Swarm-based optimization of final arrival segments considering the unmanned aircraft system integration into the non-segregated airspace. / Otimização de rotas de chegada baseada em enxame considerando a presença do VANT no espaço aéreo não segregado.

Pinto Neto, Euclides Carlos 24 April 2018 (has links)
In the past few years, there has been a growth in Unmanned Aircraft Systems (UAS) numbers in segregated airspace. However, although there is an interest in integrating large UAS into non-segregated airspace, the safety challenges on its integration arise from the inclusion of new ways of reaching unsafe states into the airspace. Furthermore, Air Traffic Controllers (ATCo) aim to o?er appropriate levels of safety and efficiency and to solve issues present in complex situations. Although the UAS technology may be used in di?erent situations and brings several advantages to the airspace (e.g. efficiency), it may bring uncertainties due to the fact that ATCos may not be familiar with them. Throughout the years, this impact may be lower then it is nowadays due to the fact that the present lack of familiarity in the relationship between UAS and ATCo contributes to higher workload levels. Furthermore, Terminal Maneuvering Area (TMA), which composes the controlled airspace and in which the final sector in contained, is a critical control area normally established at the confluence of Air Traffic Service (ATS) routes in which the aircraft tend to be closer to each other. Thus, operations in this particular area are conducted carefully and, in order to achieve desirable levels of safety and efficiency, standard procedures are established. In some cases, however, standard procedures cannot be followed and the sequencing of the aircraft during the approach, which is a highly challenging task due to complex maneuvers constraints, must be performed by the ATCo in a manner to respect the minimum separation of aircraft and to avoid flights through cumulonimbus (CB). Finally, the main goal of defining a final arrival segment is to deliver the set of aircraft from the final sector of the TMA to the final phase of its landing procedure, i.e., the final approach, considering the operation efficiency and safety. The main objective of this research is to propose a parallel swarm-based method for optimizing final aircraft arrival segments design, i.e., routes that connects the final sector to the Initial Approach Fix (IAF), considering the UAS presence. This is conducted from two perspectives: ATCo workload, which is related to safety, and sequencing duration, which is related to efficiency. Furthermore, di?erent phases of UAS integration are considered, i.e., from early stages of its integration to a mature stage of its operation by means of the Technology Maturity Level (TML) usage, which is a scale that measure the familiarity between the ATCo with the aircraft. Finally, the solutions consider airspace restrictions such as minimum separation between aircraft and bad weather conditions, i.e., the presence of cumulonimbus (CB). The experiments conducted show that this approach is able to build safe and efficient solution even in situations with a high number of aircraft. / Nos últimos anos, houve um crescimento, no espaço aéreo segregado, nos números do Veículos Aéreos Não-Tripulados (VANT). No entanto, embora exista interesse em integrar grandes VANT em espaço aéreo não-segregado, os desafios de segurança decorrem da inclusão de novas formas de alcançar estados inseguros no espaço aéreo (ATCo) tem como objetivo oferecer níveis adequados de segurança e eficiência e resolver problemas presentes em situações complexas. Embora VANTs possam ser usados em diferentes situações e trazem várias vantagens para o espaço aéreo (por exemplo, eficiência), podem trazer incertezas devido ao fato de que os ATCos não estão familiarizados com essa tecnologia. Ao longo dos anos, esse impacto pode ser menor, e atualmente a falta de familiaridade na relação entre VANT e ATCo contribui para níveis mais altos de carga de trabalho. Além disso, a Área Terminal (TMA), que compõe o espaço aéreo controlado, é uma área de controle crítico normalmente estabelecida na confluência de rotas do Servi¸co de Tráfego Aéreo (ATS), nas quais as aeronaves tendem a estar mais próximas umas das outras. Assim, as operações nesta área particular são realizadas com cuidado e, para alcançar níveis desejáveis de segurança e eficiência, os procedimentos padrão são estabelecidos. Em alguns casos, no entanto, procedimentos padrão não podem ser seguidos e o sequenciamento da aeronave durante a aproximação, que é uma tarefa desafiadora por conta das restrições de manobras complexas, deve ser realizada pelo ATCo de forma a garantir separação mínima entre aeronaves e evitar voos através de cumulonimbus (CB). Finalmente, o principal objetivo de definir um segmento de chegada final ´e entregar o conjunto de aeronaves do setor final, da TMA, para a fase final do seu procedimento de pouso, ou seja, a aproximação final, considerando a eficiência e a segurança da operação. O objetivo desta pesquisa é propor um método paralelo baseado em enxame para otimizar o projeto final de segmentos de chegada de aeronaves, ou seja, rotas que conectem o setor final com o Fixo de Aproximação Inicial (IAF), considerando a presença de VANTs. Esse processo ´e conduzido a partir de duas perspectivas: a carga de trabalho do ATCo, que est´a relacionada à segurança, e a duração da sequenciamento, que está relacionado à eficiência. Além disso, são consideradas diferentes fases da integração de VANTs, ou seja, desde os primeiros estágios de sua integra¸c~ao at´e um estágio maduro de sua operação por meio do uso do Nível de Maturidade Tecnológica (TML), que é uma escala que mede a familiaridade entre o ATCo e a aeronave. Finalmente, as soluções consideram as restrições do espaço aéreo, como a separação mínima entre aeronaves e condições climáticas adversas, isto é, a presença de cumulonimbus (CB). Os experimentos realizados mostram que essa abordagem é capaz de criar soluções seguras e eficientes mesmo em situações com um grande número de aeronaves.
3

Swarm-based optimization of final arrival segments considering the unmanned aircraft system integration into the non-segregated airspace. / Otimização de rotas de chegada baseada em enxame considerando a presença do VANT no espaço aéreo não segregado.

Euclides Carlos Pinto Neto 24 April 2018 (has links)
In the past few years, there has been a growth in Unmanned Aircraft Systems (UAS) numbers in segregated airspace. However, although there is an interest in integrating large UAS into non-segregated airspace, the safety challenges on its integration arise from the inclusion of new ways of reaching unsafe states into the airspace. Furthermore, Air Traffic Controllers (ATCo) aim to o?er appropriate levels of safety and efficiency and to solve issues present in complex situations. Although the UAS technology may be used in di?erent situations and brings several advantages to the airspace (e.g. efficiency), it may bring uncertainties due to the fact that ATCos may not be familiar with them. Throughout the years, this impact may be lower then it is nowadays due to the fact that the present lack of familiarity in the relationship between UAS and ATCo contributes to higher workload levels. Furthermore, Terminal Maneuvering Area (TMA), which composes the controlled airspace and in which the final sector in contained, is a critical control area normally established at the confluence of Air Traffic Service (ATS) routes in which the aircraft tend to be closer to each other. Thus, operations in this particular area are conducted carefully and, in order to achieve desirable levels of safety and efficiency, standard procedures are established. In some cases, however, standard procedures cannot be followed and the sequencing of the aircraft during the approach, which is a highly challenging task due to complex maneuvers constraints, must be performed by the ATCo in a manner to respect the minimum separation of aircraft and to avoid flights through cumulonimbus (CB). Finally, the main goal of defining a final arrival segment is to deliver the set of aircraft from the final sector of the TMA to the final phase of its landing procedure, i.e., the final approach, considering the operation efficiency and safety. The main objective of this research is to propose a parallel swarm-based method for optimizing final aircraft arrival segments design, i.e., routes that connects the final sector to the Initial Approach Fix (IAF), considering the UAS presence. This is conducted from two perspectives: ATCo workload, which is related to safety, and sequencing duration, which is related to efficiency. Furthermore, di?erent phases of UAS integration are considered, i.e., from early stages of its integration to a mature stage of its operation by means of the Technology Maturity Level (TML) usage, which is a scale that measure the familiarity between the ATCo with the aircraft. Finally, the solutions consider airspace restrictions such as minimum separation between aircraft and bad weather conditions, i.e., the presence of cumulonimbus (CB). The experiments conducted show that this approach is able to build safe and efficient solution even in situations with a high number of aircraft. / Nos últimos anos, houve um crescimento, no espaço aéreo segregado, nos números do Veículos Aéreos Não-Tripulados (VANT). No entanto, embora exista interesse em integrar grandes VANT em espaço aéreo não-segregado, os desafios de segurança decorrem da inclusão de novas formas de alcançar estados inseguros no espaço aéreo (ATCo) tem como objetivo oferecer níveis adequados de segurança e eficiência e resolver problemas presentes em situações complexas. Embora VANTs possam ser usados em diferentes situações e trazem várias vantagens para o espaço aéreo (por exemplo, eficiência), podem trazer incertezas devido ao fato de que os ATCos não estão familiarizados com essa tecnologia. Ao longo dos anos, esse impacto pode ser menor, e atualmente a falta de familiaridade na relação entre VANT e ATCo contribui para níveis mais altos de carga de trabalho. Além disso, a Área Terminal (TMA), que compõe o espaço aéreo controlado, é uma área de controle crítico normalmente estabelecida na confluência de rotas do Servi¸co de Tráfego Aéreo (ATS), nas quais as aeronaves tendem a estar mais próximas umas das outras. Assim, as operações nesta área particular são realizadas com cuidado e, para alcançar níveis desejáveis de segurança e eficiência, os procedimentos padrão são estabelecidos. Em alguns casos, no entanto, procedimentos padrão não podem ser seguidos e o sequenciamento da aeronave durante a aproximação, que é uma tarefa desafiadora por conta das restrições de manobras complexas, deve ser realizada pelo ATCo de forma a garantir separação mínima entre aeronaves e evitar voos através de cumulonimbus (CB). Finalmente, o principal objetivo de definir um segmento de chegada final ´e entregar o conjunto de aeronaves do setor final, da TMA, para a fase final do seu procedimento de pouso, ou seja, a aproximação final, considerando a eficiência e a segurança da operação. O objetivo desta pesquisa é propor um método paralelo baseado em enxame para otimizar o projeto final de segmentos de chegada de aeronaves, ou seja, rotas que conectem o setor final com o Fixo de Aproximação Inicial (IAF), considerando a presença de VANTs. Esse processo ´e conduzido a partir de duas perspectivas: a carga de trabalho do ATCo, que est´a relacionada à segurança, e a duração da sequenciamento, que está relacionado à eficiência. Além disso, são consideradas diferentes fases da integração de VANTs, ou seja, desde os primeiros estágios de sua integra¸c~ao at´e um estágio maduro de sua operação por meio do uso do Nível de Maturidade Tecnológica (TML), que é uma escala que mede a familiaridade entre o ATCo e a aeronave. Finalmente, as soluções consideram as restrições do espaço aéreo, como a separação mínima entre aeronaves e condições climáticas adversas, isto é, a presença de cumulonimbus (CB). Os experimentos realizados mostram que essa abordagem é capaz de criar soluções seguras e eficientes mesmo em situações com um grande número de aeronaves.
4

Fluvial Processes in Motion: Measuring Bank Erosion and Suspended Sediment Flux using Advanced Geomatic Methods and Machine Learning

Hamshaw, Scott Douglas 01 January 2018 (has links)
Excessive erosion and fine sediment delivery to river corridors and receiving waters degrade aquatic habitat, add to nutrient loading, and impact infrastructure. Understanding the sources and movement of sediment within watersheds is critical for assessing ecosystem health and developing management plans to protect natural and human systems. As our changing climate continues to cause shifts in hydrological regimes (e.g., increased precipitation and streamflow in the northeast U.S.), the development of tools to better understand sediment dynamics takes on even greater importance. In this research, advanced geomatics and machine learning are applied to improve the (1) monitoring of streambank erosion, (2) understanding of event sediment dynamics, and (3) prediction of sediment loading using meteorological data as inputs. Streambank movement is an integral part of geomorphic changes along river corridors and also a significant source of fine sediment to receiving waters. Advances in unmanned aircraft systems (UAS) and photogrammetry provide opportunities for rapid and economical quantification of streambank erosion and deposition at variable scales. We assess the performance of UAS-based photogrammetry to capture streambank topography and quantify bank movement. UAS data were compared to terrestrial laser scanner (TLS) and GPS surveying from Vermont streambank sites that featured a variety of bank conditions and vegetation. Cross-sectional analysis of UAS and TLS data revealed that the UAS reliably captured the bank surface and was able to quantify the net change in bank area where movement occurred. Although it was necessary to consider overhanging bank profiles and vegetation, UAS-based photogrammetry showed significant promise for capturing bank topography and movement at fine resolutions in a flexible and efficient manner. This study also used a new machine-learning tool to improve the analysis of sediment dynamics using three years of high-resolution suspended sediment data collected in the Mad River watershed. A restricted Boltzmann machine (RBM), a type of artificial neural network (ANN), was used to classify individual storm events based on the visual hysteresis patterns present in the suspended sediment-discharge data. The work expanded the classification scheme typically used for hysteresis analysis. The results provided insights into the connectivity and sources of sediment within the Mad River watershed and its tributaries. A recurrent counterpropagation network (rCPN) was also developed to predict suspended sediment discharge at ungauged locations using only local meteorological data as inputs. The rCPN captured the nonlinear relationships between meteorological data and suspended sediment discharge, and outperformed the traditional sediment rating curve approach. The combination of machine-learning tools for analyzing storm-event dynamics and estimating loading at ungauged locations in a river network provides a robust method for estimating sediment production from catchments that informs watershed management.
5

Selected Aspects of Navigation and Path Planning in Unmanned Aircraft Systems

Wzorek, Mariusz January 2011 (has links)
Unmanned aircraft systems (UASs) are an important future technology with early generations already being used in many areas of application encompassing both military and civilian domains. This thesis proposes a number of integration techniques for combining control-based navigation with more abstract path planning functionality for UASs. These techniques are empirically tested and validated using an RMAX helicopter platform used in the UASTechLab at Linköping University. Although the thesis focuses on helicopter platforms, the techniques are generic in nature and can be used in other robotic systems. At the control level a navigation task is executed by a set of control modes. A framework based on the abstraction of hierarchical concurrent state machines for the design and development of hybrid control systems is presented. The framework is used to specify  reactive behaviors and for sequentialisation of control modes. Selected examples of control systems deployed on UASs are presented. Collision-free paths executed at the control level are generated by path planning algorithms.We propose a path replanning framework extending the existing path planners to allow dynamic repair of flight paths when new obstacles or no-fly zones obstructing the current flight path are detected. Additionally, a novel approach to selecting the best path repair strategy based on machine learning technique is presented. A prerequisite for a safe navigation in a real-world environment is an accurate geometrical model. As a step towards building accurate 3D models onboard UASs initial work on the integration of a laser range finder with a helicopter platform is also presented. Combination of the techniques presented provides another step towards building comprehensive and robust navigation systems for future UASs.

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