From 2010 to 2030, the number of instrument flight rules aircraft operations handled by Federal Aviation Administration en route traffic centers is predicted to increase from approximately 39 million flights to 64 million flights. The projected growth in air transportation demand is likely to result in traffic levels that exceed the abilities of the unaided air traffic controller in managing, separating, and providing services to aircraft. Consequently, the Federal Aviation Administration, and other air navigation service providers around the world, are making several efforts to improve the capacity and throughput of existing airspaces. Ultimately, the stated goal of the Federal Aviation Administration is to triple the available capacity of the National Airspace System by 2025. In an effort to satisfy air traffic demand through the increase of airspace capacity, air navigation service providers are considering the inclusion of advisory conflict-detection and resolution systems. In a human-in-the-loop framework, advisory conflict-detection and resolution decision-support tools identify potential conflicts and propose resolution commands for the air traffic controller to verify and issue to aircraft. A number of researchers and air navigation service providers hypothesize that the inclusion of combined conflict-detection and resolution tools into air traffic control systems will reduce or transform controller workload and enable the required increases in airspace capacity. In an effort to understand the potential workload implications of introducing advisory conflict-detection and resolution tools, this thesis provides a detailed study of the conflict event process and the implementation of conflict-detection and resolution algorithms. Specifically, the research presented here examines a metric of controller taskload: how many resolution commands an air traffic controller issues under the guidance of a conflict-detection and resolution decision-support tool. The goal of the research is to understand how the formulation, capabilities, and implementation of conflict-detection and resolution tools affect the controller taskload (system demands) associated with the conflict-resolution process, and implicitly the controller workload (physical and psychological demands). Furthermore this thesis seeks to establish best practices for the design of future conflict-detection and resolution systems. To generalize conclusions on the conflict-resolution taskload and best design practices of conflict-detection and resolution systems, this thesis focuses on abstracting and parameterizing the behaviors and capabilities of the advisory tools. Ideally, this abstraction of advisory decision-support tools serves as an alternative to exhaustively designing tools, implementing them in high-fidelity simulations, and analyzing their conflict-resolution taskload. Such an approach of simulating specific conflict-detection and resolution systems limits the type of conclusions that can be drawn concerning the design of more generic algorithms. In the process of understanding conflict-detection and resolution systems, evidence in the thesis reveals that the most effective approach to reducing conflict-resolution taskload is to improve conflict-detection systems. Furthermore, studies in the this thesis indicate that there is significant flexibility in the design of conflict-resolution algorithms.

The aviation industry evolves all the time in every possible sphere with new the technology that is advancing and the increasing amount of traffic on the airports. The air traffic control services has come a long way with automated systems and more advanced technology and the work of the air traffic controller (ATCO) has become more efficient to meet the higher demands for more traffic. But along with highly automated systems and work efficiency there can be a lack of safety instead if there is too much to do for the controller. A new concept in the aviation industry is developing; multiple remote towers, which means that one ATCO can be several miles away from the airports and handle two or more airports at the same time from the same work station. The air traffic controllers has to monitor the aircrafts, direct the traffic, make decisions and make sure that the pilots follows the instructions. At the same time the ATCO need to monitor the systems as well, making sure that everything is working as it is supposed to. To be able to maintain a safe environment for the controllers and the aircrafts, on and surrounding the runways, the controllers need to have situation awareness and the system they are working within need to be resilient to be able to cope with the different kind of situations that might occur. This study has focused on the role of the ATCO in air traffic control towers and by eye-tracking mapped what the controllers are looking at while handling arrivals in two different air traffic control towers. An episode analysis was made on several episodes that took place during different kinds of conditions in the two different air traffic control tower simulators, one single tower simulator and one multiple remote tower simulator. Patterns in the controllers’ way of handling arrivals were identified and the results from the controllers’ eye-movements shows that the ATCOs have a habitual behaviour pattern and that for almost every arrival they will act in the same way. The ATCO in the single tower simulator used the air radar several times during the episodes while in the multiple remote tower simulator the ATCOs almost never looked at the air radar. The radio was used more by the controllers in the multiple remote tower than in the single tower and it is discussed if this is something that can take too much time from an ATCO in a multiple remote tower. The results also highlights the importance of the strip-table, a tool used by the controllers during every step of the arrival process. The conclusions are that the system (controllers and non-human agents) has situation awareness and that the air traffic controllers have a clear frame of the situation. The results from this study can be seen as a guideline and a start for further research in this field and for the development of multiple remote towers. Further research should investigate in the controllers’ ability of reframing in situations of runway incursions and other unexpected events and the usage of the radio in multiple remote towers.

<p>Multiple target tracking (MTT) is a major area that occurs in a variety of real world systems. The problem involves the detection and estimation of an unknown number of targets within a scenario space given a sequence of noisy, incomplete measurements. The classic approach to MTT performs data association between individual measurements, however, this step is a computationally complex problem. Recently, a series of algorithms based on Random Finite Set (RFS) theory, that do not require data association, have been introduced. This thesis addresses some of the main deficiencies involved with RFS methods and derives key extensions to improve them for use in real world systems.\\</p> <p>The first contribution is the Weight Partitioned PHD filter. It separates the Probability Hypothesis Density (PHD) surface into partitions that represent the individual state estimates both spatially and proportionally. The partitions are labeled and propagated over several time steps to form continuous track estimates. Multiple variants of the filter are presented. Next, the Multitarget Multi-Bernoulli (MeMBer) filter is extended to allow the tracking of manoeuvring targets. A model state variable is incorporated into the filter framework to estimate the probability of each motion model. The standard implementations are derived. Finally, a new linear variant of the Intensity filter (iFilter) is presented. A Gaussian Mixture approximation provides more computationally efficient implementation of the iFilter.</p> <p>Each of the new algorithms are validated on simulated data using standard multitarget tracking metrics. In each case, the methods improve on several aspects of multitarget tracking in the real world.</p> / Doctor of Engineering (DEng)

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006. / A radar system observes an aircraft once during each scan of the airspace, and uses these observations to construct a track representing a possible route of the aircraft. However when aircraft interact closely there is the possiblility of confusing the identities of the tracks. In this thesis multiple hypothesis techniques are applied to extract an identity confidence from a track, given a set of possible tracks and observations. The system utilises numerous estimation filters internally and these are investigated and compared in detail. The Identity Confidence algorithm is tested using a developed radar simulation system, and evaluated sucessfully against a series of benchmark tests.

The consequences of traffic congestion include increased travel time, fuel consumption, and the number of crashes. Studies suggest that most traffic delays are due to nonrecurring traffic congestion. Adaptive traffic control using real-time data is effective in dealing with nonrecurring traffic congestion. Many adaptive traffic control algorithms used today are deterministic and prone to human error and limitation. Reinforcement learning allows the development of an optimal traffic control policy in an unsupervised manner. We have implemented a reinforcement learning algorithm that only requires information about the number of vehicles and the mean speed of each incoming road to streamline traffic in a four-way intersection. The reinforcement learning algorithm is evaluated against a deterministic algorithm and a fixed-time control schedule. Furthermore, it was tested whether reinforcement learning can be trained to prioritize emergency vehicles while maintaining good traffic flow. The reinforcement learning algorithm obtains a lower average time in the system than the deterministic algorithm in eight out of nine experiments. Moreover, the reinforcement learning algorithm achieves a lower average time in the system than the fixed-time schedule in all experiments. At best, the reinforcement learning algorithm performs 13% better than the deterministic algorithm and 39% better than the fixed-time schedule. Moreover, the reinforcement learning algorithm could prioritize emergency vehicles while maintaining good traffic flow.

Este trabalho propõe um modelo de análise quantitativa baseado em simulação de eventos discretos para a determinação do nível de resiliência em sistemas de transporte. O nível de resiliência é avaliado considerando as funções de desempenho relacionadas a capacidade, ao nível de serviço e ao tempo de recuperação do sistema de transporte frente a um evento de ruptura. O modelo é validado através de estudo de caso aplicado ao sistema de tráfego aéreo brasileiro, considerando um espaço aéreo composto por 12 setores de uma região de informação de voo (FIR), suas demandas diárias de aeronaves, sua malha de rotas aéreas e sua rede de aeródromos instalada. O evento de ruptura é oriundo de condições meteorológicas adversas que afetam simultaneamente as operações de pouso e decolagem no aeroporto do Rio de Janeiro - Santos Dumont (SBRJ) e no aeroporto de São Paulo - Congonhas (SBSP). Conclui-se que o modelo de análise permite a plena determinação do nível de resiliência em sistemas de transportes, mesmo em situações de rupturas operacionais simultâneas. / This work proposes a quantitative analysis model based on discrete event simulation (DES) to determine the resilience level of transport systems. The resilience level is evaluated considering the performance functions related to capacity, service level and recovery time of the transport system in a presence of disruptive events. The model is validated through a case study applied to the Brazilian air traffic system, considering an airspace with 12 sectors of a flight information region (FIR), its daily aircraft demands, its air route network and its aerodromes network installed. The disruptive event comes from adverse weather conditions that simultaneously affect the landing and takeoff operations at Rio de Janeiro - Santos Dumont (SBRJ) and São Paulo - Congonhas (SBSP) airports. It is concluded that the analysis model allows the full determination of the resilience level in transport systems, even in situations of simultaneous operational disruptions.

Este trabalho aborda o problema decorrente da necessidade de realizar tráfego multicast em redes ATM. Para isto, foi proposta uma arquitetura para a estrutura de célula da chave, mais especificamente a estrutura de roteamento de células no interior da chave ATM. Como o ATM se propõe a atender a todas as exigências do B-ISDN, a necessidade essencial da chave ATM, é que o transporte de células entre suas portas de entrada e saída se faça o mais rápido possível. Para se conseguir isso, a arquitetura proposta não utiliza buffer nos seus elementos de roteamento. O trabalho não implementa no todo a chave ATM, deixando em aberto o problema da perda de seqüência de células no interior da estrutura de roteamento, que seria uma responsabilidade do módulo de saída da chave. A arquitetura proposta foi modelada e um simulador foi construído para a realização dos testes. Para as simulações foram levados em conta os tráfegos de células unicast e multicast. Como as células unicast e as cópias das células multicast disputavam por um mesmo link de saída, foi proposta uma estratégia para separar estas células. Isto resultou no projeto de posicionar a rede de cópia de células no segundo estágio da estrutura de roteamento, deixando o primeiro estágio para o roteamento das células unicast. O resultado disso foi um segundo estágio agora destinado para as cópias de células multicast absolutamente descongestionado, reduzindo \'drasticamente a possibilidade de disputa por um link de saída. Além disso, a estrutura incorpora os conceitos de TBSF (Tandem Banyan Switch Fabric), e duplicidade de rota, que tornam a estrutura extremamente modular e flexível. Para atender a preocupação em separar o tráfego, foi introduzido entre um estágio e outro da rede Banyan, uma saída de fuga, permitindo que células que tenham atingido a porta de saída desejada possam deixar a estrutura. São apresentados os resultados da simulação, objetivando a validação do trabalho proposto. / This thesis addresses the problem of accomplishing multicast traffic in ATM networks. An architecture is proposed for the cell structure of the switch, more specifically the routing of cells inside an ATM switch. Because ATM tries to satisfy all the demands of the B-ISDN model, an ATM switch must transport cells between its input and output ports as fast as possible. To achieve that, the proposed architecture does not use buffers in its commutation elements. This work does not implement a complete ATM switch, leaving the problem of the loss of sequence of cells inside the routing structure open. This problem must be solved by the output module of the switch. The proposed architecture was modeled and a simulator was built for testing purposes. For the simulations, both the unicast and the multicast traffic were taken into account. As the unicast cells and the copies of the multicast cells disputed for the same output link, a strategy was proposed to separate these cells. This resulted in the positioning of the cell copy network in the second stage of the routing structure, leaving the first stage for the routing of unicast cells. The result was a very free second stage used for copying multicast cells. This new stage reduced the contention for an exit link. The structure incorporates the concepts of TBSF, and route duplicity, which make it extremely modular and flexible. To separate the traffic, it was introduced between the two stages of the Banyan Network an escape exit, allowing cells that have reached the correct output port to leave the structure.

O objetivo desse trabalho foi avaliar os possíveis danos causados pelo tráfego acidental de veículos agrícolas sobre as soqueiras de cana-de-açúcar no momento da colheita mecanizada. Isto foi feito através da aplicação de diferentes cargas em soqueiras recém colhidas, sob condição controlada, tendo como referência as cargas típicas aplicadas ao solo por um conjunto trator-transbordo, identificando seus efeitos no solo e na planta. Foram conduzidos experimentos em duas áreas com características homogêneas, porém com diferentes texturas de solo, sendo uma área mais argilosa e outra mais arenosa. Foi utilizado um trator para reprodução das cargas de tráfego sobre a soqueira e foram definidos cinco tratamentos, sendo três deles simulando possíveis condições de tráfego sobre as soqueiras, um tratamento que simulou uma condição de perfeito controle de tráfego e a testemunha, sem tráfego. Após as simulações de tráfego foram avaliadas características de solo (compactação e densidade), da planta (falhas de brotação, perfilhamento, biometria e produtividade) além da análise tecnológica da matéria-prima. Os resultados indicaram forte influência do tráfego acidental sobre as soqueiras em relação ao aumento da compactação do solo. Na área experimental com maior teor de argila houve significativa redução da produtividade nos tratamentos onde houve tráfego sobre as soqueiras e na área experimental de textura arenosa as diferenças não foram significativas. Não houve influência dos tratamentos na qualidade da matéria-prima nem nas falhas de brotação e perfilhamento. Para as características biométricas, o tráfego sobre as soqueiras causou redução do comprimento dos colmos na área mais argilosa. O experimento permitiu concluir que o tráfego acidental sobre as soqueiras promoveu alterações no solo, que foram mais intensas no solo argiloso, gerando reflexos negativos nas plantas e que o controle de tráfego permitiu alta intensidade de tráfego de rodados sem nenhuma influência na dinâmica da cultura da cana-de-açúcar. / This work aimed to evaluate possible damages caused by accidental traffic of agricultural vehicles to sugar cane ratoon at the moment of mechanized harvest. The evaluation was carried out by applying different loads on recently harvested sugar cane roots, under controlled conditions, using, as reference, typical loads applied to the soil by a sugar cane transport system composed by a tractor and infield wagons and identifying their effects on the soil and plant. The experiments were performed in two areas with similar characteristics, however with distinct soil textures - clay and sandy. A tractor was used to apply the loads and five treatments were defined, in which three of them simulated possible situation of accidental traffic on sugar cane roots, one treatment simulated the perfect condition of controlled traffic and the control (no traffic). After simulations of traffic, characteristics of soil (cone index and density) and the plant (sprout failure, sprouting number, biometrics characteristics, yield and raw material quality) were evaluated. Results show strong influence of accidental traffic on the sugar cane ratoon due to the increase of soil compaction. In the clay soil, there was significant yield reduction in the treatments where there was traffic on the sugar cane ratoon and in the sandy soil, differences were not significant. There was no difference of the treatments on the raw material quality, sprout failure and sprouting number. For the biometrical characteristics, traffic on the sugar cane ratoon caused reduction of the stem length on the clay soil. The experiments allowed to conclude that accidental traffic on the sugar cane ratoon promotes modifications in the soil, that was more intense on the clay soil, bringing negative effects on the plant and that controlling traffic permits high intensity of wheeled vehicles without affecting the dynamics of the sugar cane crop.

O controle centralizado do tráfego tem como objetivo integrar e gerenciar informações, auxiliando na tomada de decisão em tempo real. Devido ao aumento da complexidade da malha viária, principalmente em grandes cidades, muitos estudos têm focado em sistemas de controle de tráfego, incluindo desenvolvimento de novas tecnologias e ferramentas. Para gerenciar essa complexidade, é necessário que as organizações públicas, onde estão inseridos os Centros de Controle de Tráfego (CCT), conheçam e melhorem seus processos, alinhando e integrando-os aos seus sistemas de informação, de maneira a possibilitar o atendimento das demandas de forma eficiente. Nesse sentido, esta pesquisa baseia-se nos conceitos e práticas do Business Process Management (BPM) com objetivo de propor um modelo de estruturação dos processos para a gestão inteligente das informações no controle centralizado do tráfego. O trabalho, portanto, se desenvolve ao longo das fases e etapas do ciclo do BPM, contemplando desde o planejamento até a modelagem de processos e apresentando como resultado final uma proposta para um plano de otimização de processos. Assim, para atender ao objetivo principal da pesquisa, o trabalho foi desmembrado em três artigos com níveis crescentes de glanuralidade: (i) Inicialmente foi apresentada, baseada em estudo de caso, uma aplicação abrangente da metodologia, percorrendo da primeira à terceira fase do ciclo de BPM em que a empresa está apta para executar os processos e seguir para a quarta fase, Controle e Análise de Dados. (ii) O segundo artigo apresenta o detalhamento da segunda fase do ciclo de BPM, que consiste na modelagem e otimização dos processos. Os processos As Is foram, então, modelados e analisados para que pudesse ser proposta a melhoria na forma de um macroprocesso To Be. (iii) Para embasar a proposição do macroprocesso To Be, foi realizada uma revisão sistemática de literatura, na qual foram compiladas as melhores práticas no tema e verificadas para a realidade brasileira através de entrevista com especialistas. O resultado foi o Mapeamento de Melhores Práticas associado a um Modelo Referência para o Processo de Controle de Tráfego. Em complemento, foram determinadas diretrizes a serem seguidas para a gestão inteligente das informações no controle centralizado do tráfego. Esses resultados definem, portanto, um modelo de referência To Be dos processos de trabalho em CCTs. A principal contribuição teórica desta pesquisa é, então, a consolidação de melhores práticas associadas a um Modelo de Referência do Processo de Controle do Tráfego, ajustado para a realidade dos CCTs brasileiros. Do ponto de vista prático, a metodologia e os resultados apresentados incentivam a implantação de BPM não só em CCTs, mas em qualquer setor de uma organização pública. / The centralization of traffic control aims to integrate and manage information, aiding decision making in real time. Due to the increasing complexity of the road network, especially in large cities, many studies have focused on traffic control systems, including development of new technologies and tools. To manage this complexity, it is necessary that public organizations, where the Traffic Control Centers (TCC) are inserted, understand and improve their processes, aligning and integrating them into their information systems in order to enable the fulfillment of demands efficiently. In this sense, this research is based on the concepts and practices of Business Process Management (BPM) in order to propose a structuring model of processes for the intelligent management of information in centralized traffic control. The work, therefore, is developed through the phases and stages of the BPM cycle, covering from planning to process modeling and presenting as the final result a proposal for a process optimization plan. Thus, to meet the main goal of the research, the work was divided into three articles with increasing levels of detail: (i) initially it was presented, based on case study, a comprehensive application of the methodology, that cover from the first to the third phase of the BPM cycle in which the company is able to run the process and move on to the fourth phase, Control and Data Analysis. (ii) The second article presents the details of the application of second phase of the BPM cycle, which consists of modeling and optimization of processes. The processes "As Is" were modeled and analyzed in order to propose improvements trough a Macro process "To Be". (iii) To support the proposition of macroprocess “To Be”, a systematic review of the literature was applied in order to compile best practices on the subject that were checked for the Brazilian reality through interviews with experts. The result was a Map of Best Practices in association with a Reference Model for Traffic Control Process. In addition to the map, the paper presents guidelines to be followed for the intelligent management of information in centralized traffic control. These results define a reference model "To Be" of work processes in TCCs. From a practical standpoint, the methodology and results presented encourage the deployment of BPM not only in TCCs, but also in any department of a public organization.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERO. / Includes bibliographical references. / by Shinsuke Endoh. / M.S.