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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.
71

Quantifying the Effects of Uncertainty in a Decentralized Model of the National Airspace System

Sherman, Stephanie Irene 08 June 2015 (has links)
The modernization of the National Air Traffic Control System is on the horizon, and with it, the possible introduction of autonomous air vehicles into the national airspace. Per the FAA Aerospace Forecast (FAA, 2013), U.S. carrier passenger traffic is expected to average 2.2 percent growth per year over the next 20 years with government statistics indicating that the average domestic load factor for airlines in 2014 was approximately 84.4 percent (US Department of Transportation, 2015). Adding to that demand, the potential introduction of unmanned and autonomous air vehicles motivates reconsideration of control schemes. One of the proposed solutions (Eby, 1994) would involve a decentralized control protocol. Equipping each aircraft with the information necessary to navigate safely through integrated airspace becomes an information sharing problem: how much information about other aircraft is required for a pilot to safely fly the gamut of a heavily populated airspace and what paradigm shifts may be necessary to safely and efficiently utilize available airspace? This thesis describes the development of a tool for testing alternative traffic management systems, centralized or decentralized, in the presence of uncertainty. Applying a computational fluid dynamics-inspired approach to the problem creates a simulation tool to model both the movement of traffic within the airspace and also allows study of the effects of interactions between vehicles. By incorporating a Smoothed Particle Hydrodynamics (SPH) based model, discrete particle aircraft each carry a set of unique deterministic and stochastic properties. With this model, aircraft interaction can be studied to better understand how variations in the nondeterministic properties of the system affect its overall efficiency and safety. The tool is structured to be sufficiently flexible as to allow incorporation of different collision detection and avoidance rules for aircraft traffic management. / Master of Science
72

Aspekty vyhodnocení vzdušného prostoru / Aspects of airspace evaluation

Závodník, Ondřej January 2008 (has links)
Diplomová práce se zabývá jednak popisem stavu letecké dopravy a to zejména co se týče její bezpečnosti, plynulosti, propustnosti a kapacity. Výše uvedené je poté zhodnoceno v části věnující se aspektům nebezpečnosti vzdušného prostoru v jednotlivých fázích letu.
73

Indigeneity in the Air: The Highs and Lows of Asserting Tribal Airspace Sovereignty

January 2019 (has links)
abstract: Advancements in marine and aerospace technology drive legal reform in admiralty and air law. The increased accessibility and affordability of these technologies demand and motivate lawmakers and federal agencies to anticipate potential threats to peoples’ rights and resources in the seas and skies. Given the recent applications of unmanned aircraft in the public and private sectors, developments in aircraft and air law are rapidly becoming more relevant to American Indian and Alaska Native tribes. In anticipation of legal reform, tribal nations are taking steps to assert, expand, and secure their air rights before agencies or the courts attempt to divest their sovereign authority. An analysis of two case studies through a lens of water and federal Indian law locates spaces in American jurisprudence that have the legal foundation and structural capacity to support a greater presence of Indigeneity in airspace. Research findings from these studies answer the following inquiries about tribal airspace sovereignty: where does Indigeneity reside in the US national airspace system and domestic air law, how are tribal air rights strengthened or weakened by American jurisprudence, what strategies do tribes employ to exercise their sovereignty in airspace, and how are tribes planning for future developments in aircraft and air law? Answers lead to proof of how meaningful consultation through collaborative rulemaking produces far greater mutual benefits than burdens for federal agencies and tribes, and much more. Most importantly, these discoveries celebrate a diverse and accumulative strategic legacy of strengthening and expanding tribal sovereignty in the face of imminent threats and possibilities in tribal airspace. / Dissertation/Thesis / Masters Thesis American Indian Studies 2019
74

A departure regulator for closely spaced parallel runways

Robeson, Isaac J. 29 August 2011 (has links)
Increased efficiency at airports is necessary to reduce delays and fuel consumption. Many of the busiest airports in the nation have at least one pair of closely spaced parallel runways (CSPRs), defined by a separation of less than 2500 ft, with one runway dedicated to arrivals and the other to departures. CSPRs experience a large decrease in capacity under instrument conditions because they can no longer operate independently. In order to mitigate this decrease in capacity and to increase efficiency, proposed herein is a departure regulator for runways so configured, along with a plan of study to investigate the effects of this regulator. The proposed departure regulator makes use of data from precision tracking systems such as ADS-B to issue automated or semi-automated departure clearances. Assuming sequential departure separations are sufficient for clearance, the regulator will automatically issue, or advise the controller to issue, the departure clearance as soon as the arrival on the adjacent runway has descended below its decision height. By issuing the departure clearance earlier, the departure regulator reduces the gap between a pair of arrivals that is required to clear a departure. By decreasing the gap, the regulator increases the number of opportunities where a departure clearance can be issued, given a particular arrival stream. A simulation models the effects of the regulator and quantifies the resulting increases in capacity. The simulation results indicate that all forms of the regulator would provide significant gains of between 14% and 23% in capacity over the current operating paradigm. The results also indicate that the capacity gains are greatest at high arrival rates. Therefore, implementation of the departure regulator could significantly decrease the congestion at many major airports during inclement weather.
75

Airspace complexity: airspace response to disturbances

Lee, Keumjin 02 January 2008 (has links)
In ongoing efforts to balance air traffic demand and airspace capacity, airspace complexity stands as a fundamental research problem. Taking a more analytic approach, this thesis proposes that airspace complexity can be described in terms of how the airspace (together with the traffic inside it and the traffic control algorithm) responds to disturbances. The response of the airspace to a disturbance is captured by the degree of control activity required to accommodate such disturbance. Furthermore, since the response of the airspace depends on the disturbance, this thesis introduces a complexity map which shows how an airspace responses to a set of different disturbances. Among the many possible types of disturbances, this thesis considers an aircraft entering into the airspace, and the proposed method of describing airspace complexity is illustrated with examples. The time evolution of a complexity map is investigated using a statistical approach. In addition, the proposed method is illustrated in relation to current and future traffic flow management concepts. It is also shown that the proposed method can be applied to airspace design problems.
76

Through the transit zone between here and there /

Laing, Melissa. January 2008 (has links)
Thesis (Ph. D.)--University of Sydney, 2008. / Title from title screen (viewed Apr. 22, 2009) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Sydney College of the Arts. Includes bibliographical references. Also available in print form.
77

Dynamic optimization of airspace sector grouping / Optimisation du schéma de regroupement de secteurs d'espace

Treimuth, Tambet 19 January 2018 (has links)
Au cours de ces dernières décennies,au fur et à mesure de l’augmentation du trafic, l’espace aérien a été divisé en secteurs de plus en plus petits afin d’éviter la saturation de ces derniers. Ce principe de sectorisation présente une limite dans la mesure où l’on doit ménager un temps suffisant au contrôleur pour gérer son trafic et donc générer des secteurs dont la taille permet de satisfaire cette contrainte. De plus, le contrôleur ne connaît que le trafic lié à son secteur et lorsqu’un avion passe d’un secteur à un autre,il s’opère un dialogue entre les contrôleurs et les pilotes qui induit une charge de travail supplémentaire(coordination).Au cours d’une journée de trafic ordinaire,la charge de contrôle fluctue dans le temps en fonction des demandes de trafic entre les diverses paires origine-destination. Dans le système opérationnel actuel, le nombre de contrôleurs varie en fonction des fluctuations de trafic. La nuit par exemple, le nombre d’équipes de contrôle est réduit car il y a beaucoup moins de trafic.Les secteurs sont alors regroupés en groupe de trois à quatre avant attribution à une équipe de contrôleurs. Il est donc nécessaire d’optimiser la planification sur une journée du schéma de regroupement et de dégroupement des secteurs: resectorisation dynamique de l’espace aérien. Un des objectifs est de fournir des groupes de secteurs présentant un minimum de coordinations et équilibrés en terme de charge de contrôle afin que chaque équipe de contrôleurs travaille de la même façon. Les instants de commutation entre configurations de secteurs en fonction des fluctuations de trafic doivent être déterminés, et les distances entre configurations successives doivent être prises en compte afin d’éviter des changements brusques au sein d’un espace aérien donné. Le développement d’un algorithme efficace pour résoudre le problème dynamique résultant est d’autant plus important que le trafic aérien est amené évoluer de manière significative au cours des années qui viennent. / The current airspace configuration is highly structured, fixed and is less responsive to changes causing the overall system to lack the flexibility, adaptability, and responsibility needed to handle the increasing air traffic demands in the near future. The work presented in this thesis aims at improving the flexibility and adaptability of today's airspace management in Europe in a pretactical context. We focus on the development of a method to support a process of automatic generation of a sequence of sector configurations composed of predefined sectors. Airspace configurations should be dynamically adjusted to provide maximum efficiency and flexibility in response to demand fluctuations. We dynamically build configurations by combining existing elementary sectors. In this step, any sector combination which forms controllable airspace blocks is eligible and may be used during the day of operation. In this work, we developed efficient methods to solve DAC problem. We formulated and study the sectorization problem from an algorithmic point of view. We proposed methods based on a mathematical modeling and heuristic optimization techniques. We also introduced here an approach to evaluate the workload inside sectors.
78

Airport Performance Metrics Analysis: Application to Terminal Airspace, Deicing, and Throughput

Alsalous, Osama 08 June 2022 (has links)
The Federal Aviation Administration (FAA) is continuously assessing the operational performance of the National Airspace System (NAS), where they analyze trends in the aviation industry to help develop strategies for a more efficient air transportation system. To measure the performance of various elements of the aviation system, the FAA and the International Civil Aviation Organization (ICAO) developed nineteen key performance indicators (KPIs). This dissertation contains three research studies, each written in journal format, addressing select KPIs. These studies aim at answering questions that help understand and improve different aspects of airport operational efficiency. In the first study, we model the flight times within the terminal airspace and compare our results with the baseline methodology that the FAA uses for benchmarking. In the second study, we analyze the efficiency of deicing operations at Chicago O'Hare (ORD) by developing an algorithm that analyzes radar data. We also use a simulation model to calculate potential improvements in the deicing operations. Lastly, we present our results of a clustering analysis surrounding the response of airports to demand and capacity changes during the COVID-19 pandemic. The findings of these studies add to literature by providing a methodology that predicts travel times within the last 100 nautical miles with greater accuracy, by providing deicing times per aircraft type, and by providing insight into factors related to airport response to shock events. These findings will be useful for air traffic management decision makers in addition to other researchers in related future studies and airport simulations. / Doctor of Philosophy / The Federal Aviation Administration (FAA) is the transportation agency that regulates all aspects of civil aviation in the United States. The FAA is continuously analyzing trends in the aviation industry to help develop a more efficient air transportation system. They measure the performance of various elements of the aviation system. For example, there are indicators focused on the departure phase of flights measuring departure punctuality and additional time in taxi-out. On the arrivals side, there are indicators that measure the additional time spent in the last 100 nautical miles of flight. Additionally, there are indicators that measure the performance of the airport as a whole such as the peak capacity and the peak throughput. This dissertation contains three research studies, each one aims at answering questions that help understand and improve a different aspect of airport operational efficiency. The first study is focused on arrivals where we model the flight times within the last 100 nautical miles of flight. Our model incorporated factors such as wind and weather conditions to predict flight times within the last 100 nautical miles with greater accuracy than the baseline methodology that the FAA currently uses. The resulting more accurate benchmarks are important in helping decision makers, such as airport managers, understand the factors causing arrival delays. In the second study, we analyze the efficiency of deicing operations which can be a major source of departure delays during winter weather. We use radar data at Chicago O'Hare airport to analyze real life operations. We developed a simulation model that allowed us to recreate actual scenarios and run what-if scenarios to estimate potential improvements in the process. Our results showed potential savings of 25% in time spent in the deicing system if the airport changed their queueing style towards a first come first served rather than leaving it for the airlines to have their separate areas. Lastly, we present an analysis of the response of airports to demand and capacity changes during the COVID-19 pandemic. In this last study, we group airports by the changes in their throughput and capacity during two time periods. The first part of the study compares airports operations during 2019 to the pandemic during the "shock event" in 2020. The second part compares the changes in airports operations during 2020 with the "recovery" time period using data from 2021. This analysis showed which airports reacted similarly during the shock and recovery. It also showed the relationship between airport response and factors such as what kind of airlines use the airport, airport hub size, being located in a multi-airport city, percentage of cargo operations. The results of this study can help in understanding airport resilience based on known airport characteristics, this is particularly useful for predicting airport response to future disruptive events.
79

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.

Gimenes, Ricardo Alexandre Veiga 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.
80

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.

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