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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.
11

A Computer Model to Estimate Commercial Aviation Fuel Consumption and Emissions in the Continental United States

Zou, Zhihao 03 January 2013 (has links)
A comprehensive model is developed to estimate and predict the fuel consumption and emissions by domestic commercial aviation in the Continental United States. Most of the existing fuel consumption and emission models are limited in their ability to predict the annual fuel burn for air transportation at the national level. For example, those models either require real track data or are developed only to model single flight scenarios.  The model developed in this thesis is part of a software framework called the Transportation Systems Analysis Model (TSAM). The model has the capability to estimate fuel consumption and emissions for millions of domestic flights in a year in the continental U.S. TSAM is a nationwide, long-distance, multimodal travel demand forecast model developed at Virginia Tech. The model enables TSAM to quantify fuel and emission metrics for various modes of transportation. The EUROCONTROL Base of Aircraft Data (BADA) is employed as the Aircraft Performance Model to simulate individual flight profiles and calculate fuel burn rates. Fuel consumption on the ground (taxi mode) is estimated separately. Different operational conditions like wind states, terminal area detour, cruise altitude and airport elevation are considered in the model. Emissions of HC, CO, NOx and SOx are computed inside the Landing/Take-off (LTO) cycle based on the fuel consumption estimate, while greenhouse gas of CO2 is calculated for the complete flight cycle. / Master of Science
12

A methodology for the valuation and selection of adaptable technology portfolios and its application to small and medium airports

Pinon, Olivia Julie 27 March 2012 (has links)
The increase in the types of airspace users (large aircraft, small and regional jets, very light jets, unmanned aerial vehicles, etc.), as well as the very limited number of future new airport development projects are some of the factors that will characterize the next decades in air transportation. These factors, associated with a persistent growth in air traffic will worsen the current gridlock situation experienced at some major airports. As airports are becoming the major capacity bottleneck to continued growth in air traffic, it is therefore primordial to make the most efficient use of the current, and very often, underutilized airport infrastructure. This research thus proposes to address the increase in air traffic demand and resulting capacity issues by considering the implementation of operational concepts and technologies at underutilized airports. However, there are many challenges associated with sustaining the development of this type of airports. First, the need to synchronize evolving technologies with airports' needs and investment capabilities is paramount. Additionally, it was observed that the evolution of secondary airports, and their needs, is tightly linked to the environment in which they operate. In particular, sensitivity of airports to changes in the dynamics of their environment is important, therefore requiring that the factors that drive the need for capacity expansion be identified and characterized. Finally, the difficulty to evaluate risk and make financially viable decisions, particularly when investing in new technologies, cannot be ignored. This work thus focuses on the development of a methodology to address these challenges and ensure the sustainability of airport capacity-enhancement investments in a continuously changing environment. The four-step process developed in this research leverages the benefits yielded by impact assessment techniques, system dynamics modeling, and real options analysis to 1) provide the decision maker with a rigorous, structured, and traceable process for technology selection, 2) assess the combined impact of interrelated technologies, 3) support the translation of technology impact factors into airport performance indicators, and help identify the factors that drive the need for capacity expansion, and finally 4) enable the quantitative assessment of the strategic value of embedding flexibility in the formulation of technology portfolios and investment options. The proposed methodology demonstrates, through a change in demand at the airport modeled, the importance of being able to weigh both the technological and strategic performance of the technology portfolios considered. Hence, by capturing the time dimension and technology causality impacts in technology portfolio selection, this work helps identify key technologies or technology groupings, and assess their performance on airport metrics. By embedding flexibility in the formulation of investment scenarios, it provides the decision maker with a more accurate picture of the options available to him, as well as the time and sequence under which these should be exercised.
13

Airport control through intelligent gate assignment

Kim, Sang Hyun 13 January 2014 (has links)
This dissertation aims at improving the efficiency, robustness, and flexibility of airport operations through intelligent gate assignment. Traditional research on gate assignment focuses on the accommodation of passengers' demands such as walking time of passengers, and the robustness of gate assignment. In spite of its importance on the ramp operations, there is a lack of research to account ramp congestion when gates are assigned. Therefore, this dissertation proposes a new perspective on the gate assignment that accounts for ramp congestion. For that purpose, a ramp operations model based on observations at Atlanta airport is presented to understand the characteristics of aircraft movement on the ramp. The proposed gate assignment problem minimizes passenger-time spent on ramp areas. In addition, this dissertation is conducted to satisfy the needs of passengers, aircraft, and operations from the perspectives of passengers. Using actual passenger data at a major hub airport, the proposed gate assignment is assessed by means of passengers' transit time, passengers' time spent on the ramp, and passengers' waiting time for a gate. Results show that the proposed gate assignment outperforms the current gate assignment in every metric. This dissertation also analyzes the impact of gate assignment on departure metering, which controls the number of pushbacks in order to reduce airport congestion. Then, some of departing flights are held at gates, so it increases the chance of gate conflict, which reduces the efficiency of departure metering as well as ramp operations. In order to analyze the impact of gate assignment on departure metering, this dissertation simulates departure processes at two airports. Results show that the proposed robust gate assignment reduces the occurrence of gate conflicts under departure metering and helps to utilize gate-holding times to some extent.
14

Detecting flight trajectory anomalies and predicting diversions in freight transportation

Di Ciccio, Claudio, van der Aa, Han, Cabanillas Macias, Cristina, Mendling, Jan, Prescher, Johannes 31 May 2016 (has links) (PDF)
Timely identifying flight diversions is a crucial aspect of efficient multi-modal transportation. When an airplane diverts, logistics providers must promptly adapt their transportation plans in order to ensure proper delivery despite such an unexpected event. In practice, the different parties in a logistics chain do not exchange real-time information related to flights. This calls for a means to detect diversions that just requires publicly available data, thus being independent of the communication between different parties. The dependence on public data results in a challenge to detect anomalous behavior without knowing the planned flight trajectory. Our work addresses this challenge by introducing a prediction model that just requires information on an airplane's position, velocity, and intended destination. This information is used to distinguish between regular and anomalous behavior. When an airplane displays anomalous behavior for an extended period of time, the model predicts a diversion. A quantitative evaluation shows that this approach is able to detect diverting airplanes with excellent precision and recall even without knowing planned trajectories as required by related research. By utilizing the proposed prediction model, logistics companies gain a significant amount of response time for these cases.
15

O comportamento do usuário do transporte aéreo frente à variabilidade do tempo de viagem

Weber, Fernanda David January 2015 (has links)
A demanda por transporte é derivada, e seu resultado está relacionado à necessidade de superar barreiras físicas, envolvendo deslocamentos e, consequentemente, tempo. Como a sociedade moderna é orientada pelo relógio, tempo pode ser considerada uma variável de grande importante na dinâmica diária. Sendo assim, os sistemas de transporte têm papel fundamental para garantir que essa dinâmica seja atendida dentro do esperado. Portanto, os sistemas de transporte devem prover um serviço confiável. Ou seja, a operação dos mesmos deve ser regular, resultando em uma variabilidade mínima no tempo de viagem. Esse trabalho tem por objetivo analisar o comportamento do usuário do transporte aéreo frente à variabilidade do tempo de viagem. Para isso, modelos comportamentais foram estimados a partir de um estudo de caso realizado em Porto Alegre, Rio Grande do Sul, com os viajantes que frequentam o Aeroporto Internacional Salgado Filho. Uma comparação entre diferentes abordagens comportamentais, baseadas na teoria da utilidade esperada, também foi contemplada no estudo, com o intuito de encontrar o melhor modelo representativo do comportamento do público estudado. Os modelos estimados apresentam diferentes formas funcionais não lineares, caracterizando diferentes reações dos tomadores de decisão quando em situações de risco. / The demand for transport is derived, and the result is related to the need to overcome the physical barriers involving displacements and hence time. As modern society is driven by the clock, time can be considered a great important variable in the daily dynamics. Thus, the transport systems has a key role to ensure that this dynamic is met as expected. Therefore, transport systems should provide a reliable service. That is, the operation there of is regular, resulting in a minimal variability in travel time. This work aims to study the air transport user behavior against the variability of travel time. To do this, behavioral models were estimated from a case study conducted in Porto Alegre, Rio Grande do Sul, with travelers attending the Salgado Filho International Airport. A comparison between different behavioral approaches based on expected utility theory, the study was also considered in order to find the best studied model representative of the behavior of the public. The estimated models have different nonlinear functional forms, featuring different reactions of decision-makers when at risk.
16

O comportamento do usuário do transporte aéreo frente à variabilidade do tempo de viagem

Weber, Fernanda David January 2015 (has links)
A demanda por transporte é derivada, e seu resultado está relacionado à necessidade de superar barreiras físicas, envolvendo deslocamentos e, consequentemente, tempo. Como a sociedade moderna é orientada pelo relógio, tempo pode ser considerada uma variável de grande importante na dinâmica diária. Sendo assim, os sistemas de transporte têm papel fundamental para garantir que essa dinâmica seja atendida dentro do esperado. Portanto, os sistemas de transporte devem prover um serviço confiável. Ou seja, a operação dos mesmos deve ser regular, resultando em uma variabilidade mínima no tempo de viagem. Esse trabalho tem por objetivo analisar o comportamento do usuário do transporte aéreo frente à variabilidade do tempo de viagem. Para isso, modelos comportamentais foram estimados a partir de um estudo de caso realizado em Porto Alegre, Rio Grande do Sul, com os viajantes que frequentam o Aeroporto Internacional Salgado Filho. Uma comparação entre diferentes abordagens comportamentais, baseadas na teoria da utilidade esperada, também foi contemplada no estudo, com o intuito de encontrar o melhor modelo representativo do comportamento do público estudado. Os modelos estimados apresentam diferentes formas funcionais não lineares, caracterizando diferentes reações dos tomadores de decisão quando em situações de risco. / The demand for transport is derived, and the result is related to the need to overcome the physical barriers involving displacements and hence time. As modern society is driven by the clock, time can be considered a great important variable in the daily dynamics. Thus, the transport systems has a key role to ensure that this dynamic is met as expected. Therefore, transport systems should provide a reliable service. That is, the operation there of is regular, resulting in a minimal variability in travel time. This work aims to study the air transport user behavior against the variability of travel time. To do this, behavioral models were estimated from a case study conducted in Porto Alegre, Rio Grande do Sul, with travelers attending the Salgado Filho International Airport. A comparison between different behavioral approaches based on expected utility theory, the study was also considered in order to find the best studied model representative of the behavior of the public. The estimated models have different nonlinear functional forms, featuring different reactions of decision-makers when at risk.
17

O comportamento do usuário do transporte aéreo frente à variabilidade do tempo de viagem

Weber, Fernanda David January 2015 (has links)
A demanda por transporte é derivada, e seu resultado está relacionado à necessidade de superar barreiras físicas, envolvendo deslocamentos e, consequentemente, tempo. Como a sociedade moderna é orientada pelo relógio, tempo pode ser considerada uma variável de grande importante na dinâmica diária. Sendo assim, os sistemas de transporte têm papel fundamental para garantir que essa dinâmica seja atendida dentro do esperado. Portanto, os sistemas de transporte devem prover um serviço confiável. Ou seja, a operação dos mesmos deve ser regular, resultando em uma variabilidade mínima no tempo de viagem. Esse trabalho tem por objetivo analisar o comportamento do usuário do transporte aéreo frente à variabilidade do tempo de viagem. Para isso, modelos comportamentais foram estimados a partir de um estudo de caso realizado em Porto Alegre, Rio Grande do Sul, com os viajantes que frequentam o Aeroporto Internacional Salgado Filho. Uma comparação entre diferentes abordagens comportamentais, baseadas na teoria da utilidade esperada, também foi contemplada no estudo, com o intuito de encontrar o melhor modelo representativo do comportamento do público estudado. Os modelos estimados apresentam diferentes formas funcionais não lineares, caracterizando diferentes reações dos tomadores de decisão quando em situações de risco. / The demand for transport is derived, and the result is related to the need to overcome the physical barriers involving displacements and hence time. As modern society is driven by the clock, time can be considered a great important variable in the daily dynamics. Thus, the transport systems has a key role to ensure that this dynamic is met as expected. Therefore, transport systems should provide a reliable service. That is, the operation there of is regular, resulting in a minimal variability in travel time. This work aims to study the air transport user behavior against the variability of travel time. To do this, behavioral models were estimated from a case study conducted in Porto Alegre, Rio Grande do Sul, with travelers attending the Salgado Filho International Airport. A comparison between different behavioral approaches based on expected utility theory, the study was also considered in order to find the best studied model representative of the behavior of the public. The estimated models have different nonlinear functional forms, featuring different reactions of decision-makers when at risk.
18

Inferências de condutas em um oligopólio diferenciado : estudos sobre o comportamento do entrante em transporte aéreo no Brasil / Conduct inferences in a differentiated oligopoly : studies on the behavior of the entering firm in Brasilian air transportation

Bettini, Humberto Filipe de Andrade Januario 27 February 2013 (has links)
Orientador: José Maria FerreiraJardim da Silveira / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Economia / Made available in DSpace on 2018-08-22T19:30:33Z (GMT). No. of bitstreams: 1 Bettini_HumbertoFilipedeAndradeJanuario_D.pdf: 4068438 bytes, checksum: 83f5a7b43126e9389c4775dbdba66788 (MD5) Previous issue date: 2013 / Resumo: Esta Tese debruça-se sobre temas teóricos e empíricos organizados em três frentes, cada qual correspondendo a um Capítulo. A primeira frente apresenta uma revisão de ocorrências do conceito de capacidade produtiva instalada em algumas vertentes de estudos microeconômicos, exprimindo aspectos relativos à sua caracterização técnica e também aspectos "estratégicos", cuja importância competitiva para as firmas que a detém será ressaltada. Na sequência, esta primeira frente conceitua capacidade produtiva no transporte aéreo e apresenta uma tipologia para suas fases decisórias, destacando implicações competitivas pertinentes em relação a temas como reversibilidade de ações e perecibilidade dos bens. Na segunda frente, o tema de investigação são os motivadores concretos por trás de entradas em mercados aéreos no Brasil recente, optando-se pela seleção de um caso. Esta frente também se desdobra em dois esforços: inicia-se por meio de uma revisão da literatura acerca de aspectos variados em Organização Industrial teórica e empírica que se mostram pertinentes à replicação de um exercício de identificação econométrica, tarefa a que se dedica a segunda parte do Capítulo. Assim, o Capítulo 2 realiza o primeiro exercício empírico presente nesta Tese, buscando estabelecer uma leitura das estratégias que cercaram a ação de entrada de uma nova empresa - a Azul Linhas Aéreas - no cenário do transporte aéreo doméstico brasileiro. Na terceira frente, repetem-se o objeto de estudo - trata-se novamente da Azul - e a metodologia empregada, a abordagem econométrica, embora se trate de um foco diferente. Após uma revisão de teorias que destacam aspectos como cognição, rotinas, tempo para reação e a distinção entre estratégias complementares e substitutas, parte-se para a especificação e a estimação do segundo exercício econométrico. Aqui o interesse são as reações em capacidade que foram postas em curso por empresas rivais já estabelecidas atendo-se às principais incumbentes, ou seja, GOL e TAM. Por meio da utilização de um modelo que decompõe a identificação das reações em termos espaciais e temporais, teorias quanto ao uso estratégico da capacidade produtiva e a extensão dos mercados relevantes poderão ser apreciadas à luz das inferências obtidas. Dentre as justificativas mais gerais para o estudo, destacam-se dois aspectos em matéria de regulação econômica: o primeiro se traduz na compreensão das condições capazes de romper com uma situação de extrema concentração de mercado. Ao longo da década de 2000, GOL e TAM paulatinamente alcançaram um patamar de dominância quase absoluta do mercado doméstico em termos agregados, configurando uma estrutura que analistas o público e os meios de comunicação (jornalismos convencional e econômico) rotularam de um "virtual duopólio". Assim, a compreensão acerca da interação estratégica que surge entre uma entrante e as duas principais incumbentes como meio para se manter ou se romper uma determinada configuração de mercado é matéria de grande relevância. Uma segunda justificativa se associa à tentativa empírica de se verificar quão substitutos entre si são os aeroportos de Viracopos, em Campinas, e os paulistanos de Congonhas e Guarulhos. Este tema, no contexto de um país com recursos escassos, déficits históricos em matéria de infra-estrutura e em pleno curso de implementar um processo de concessão de aeroportos - Campinas / Viracopos e São Paulo / Guarulhos inclusos - reveste-se de grande importância. Dentre os achados, corrobora-se a hipótese de que a Azul privilegia adensar operações a partir de aeroportos já integrados em sua rede, e também opta por adicionar ligações que contribuam para a conectividade de passageiros dentro do seu sistema de operações. Ademais, encontraram-se indícios que corroboram a hipótese de haver alguma substituição e alguma complementaridade entre o aeroporto campineiro e os terminais que atendem a Região Metropolitana de São Paulo, resultado que nos ampara na enunciação de recomendações em termos de políticas públicas, e também indícios quanto à diferença nas reações de GOL e TAM, o que sugere diferentes nichos de mercado e/ou diferentes utilizações de afiliadas regionais / Abstract: This Thesis is made of theoretical and empirical themes organized into three fronts, each corresponding to a Chapter. The first front reviews the occurrences of the installed productive capacity concept in some Microeconomics branches, expressing aspects related to its technical character and also strategic aspects whose importance for competition between firms will be then highlighted. In sequence, this first front presents the concepts of productive capacity in air transport and presents a typology for the decision steps and putting special focus on relevant competitive consequences that come in sequence of aspects such action reversibility and good perecibility. In the second front, we investigate the concrete drivers for entries in Brazilian airline markets in current period, by opting for a case study in this task. This front is also divided in two separate efforts. We initiate with a literature review of selected aspects on fields of both theoretical and empirical Industrial Organization studies that are relevant for backing up the econometric exercise that we then develop. Therefore, Chapter 2 ends with the presentation and discussion of the first empirical exercise of this Thesis, aimed at trying to identify the strategies that surrounded market entries by Azul Airlines. In the third front, we repeat the study subject - Azul Airlines - and also the methodology employed - econometrics, but we establish an opposite focus: after another selected literature review devoted to themes such economic cognition, routines, time to react and the distinction between complementary and substitute strategies, we specify and estimate the second econometric exercise of the Thesis. Now the interest lies on capacity reactions that rival airlines (specifically GOL and TAM) carried on in an answer to Azul's market entries. Making use of a model that decomposes reactions in both time and space dimensions, theories regarding the strategic use of productive capacity and the extension of relevant markets are appreciate in the sequence of obtained inferences. Among the most general justifications for the study we carry on, we can highlight some themes in economic regulation: first, the understanding of the conditions behind the breakup of a severe market concentration is something of utmost importance. In the 2000s, GOL and TAM reached such a market concentration degree that analysts, the flying public and means of communication forged the term "virtual duopoly" for designating such structure: together, GOL and TAM had nearly a 90% market share in domestic segment. In such a scenario, to understand the strategic interaction that emerges between an entrant and the two main incumbents as a means for keeping or ruining a determined market structure is a subject of great relevance. A second justification is associated to the empirical effort devoted to identifying how substitutes are the airports of Campinas (Viracopos) and those located in the metropolitan region of São Paulo, namely Congonhas and Guarulhos. This subject is a matter of great importance in a country where there is resource scarcity, historical infrastructure deficits, and an airport concession initiative is on course, in fact including Viracopos and Guarulhos airports. Among main findings, we could see that Azul privileges the strategy of making its network denser by means of adding destinations from airports already present in its network, and also prefers to add new links that can contribute for system-wide passenger connectivity. Moreover, some elements point to the validity of the airport relation (both complementarity and substitutability) between Campinas airport and those serving the metropolitan region of São Paulo, what backs some public policy recommendations and also the notion that the main incumbents - GOL and TAM - seem to belong to different market niches, as they react differently, and/or the hypothesis that regional airlines may have been used in order to compete against the new entrant / Doutorado / Teoria Economica / Doutor em Ciências Econômicas
19

Řízení letového provozu v Evropě / Air traffic management in Europe - Single European Sky

Šyc, Petr January 2009 (has links)
Thesis analyses present status of air traffic management in European area from historical and legislative point of view. Subjects of thesis are present projects in ATM and future variants of organization of air traffic in EU. Practical part focuses on impact of ATM on air transportation.
20

Srovnání vybraných středoevropských letišť / Comparison of chosen central European airports

Kubecová, Lenka January 2015 (has links)
This Master Thesis is specialize in comparison of three central European airports in Prague, Vienna and Munich. In the first part there is general information about infrastructure of air transportation. It also includes development of air transportation and also organizations connected with aviation. After that there is some information about airports in general. This part is ended by airlines and low cost airlines. Second part of the thesis is dedicated to individual airports and their characteristics. There is some information about their history and about their attitude to environmental questions. This part also includes information about number of passengers, destinations and airlines. Third part is mostly about analysis of services like transportation to the airports, parking and other services which are compared at the end.

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