• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 17
  • 12
  • 8
  • 7
  • 5
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 69
  • 69
  • 12
  • 12
  • 11
  • 9
  • 8
  • 8
  • 8
  • 8
  • 7
  • 7
  • 7
  • 7
  • 7
  • 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.
21

Analýza vybraných věrnostních programů leteckých společností / Analysis of Selected Loyality Programs of Air Companies

Pašková, Michaela January 2012 (has links)
This work deals with loyalty programs, in airline industry mostly known as frequent flyer programs. Most airlines today offers a program in which customers can earn points as a reward for their tickets flown. The first part of the work is devoted to a research of literature on the subject, the development of loyalty programs , expected effect and their impact on clients and company profit. The second part focuses on the application of theoretical knowledge in practical study of loyalty programs of two major European airlines - Air France and Lufthansa. A practical analysis and comparison of the two programs is carried in terms of comparing the parameter and differences of the programs.
22

Economic Efficiency of Personal Air Transportation as a Technological Factor in the United States

Brooks, Jerry R. January 1950 (has links)
The purpose of this study is to examine the factors of economic efficiency embodied in the modern personal airplane and its related services in the United States, with a view to ascertaining the significance of such transportation as a technological factor in the American national economy.
23

Defining Airport Operational Sustainability for the U.S. General Aviation Airports

Yue Gu (6635894) 15 May 2019 (has links)
<p>While the general public may be familiar with commercial airports, there are thousands of small General Aviation (GA) airports serving communities across the United States. Many of these airports are under pressure to survive and to bring in more revenue without impinging on the community and environment. Many organizations and governmental agencies such as the Federal Aviation Administration (FAA), now recognize the value of sustainable development and importance of operation to airport sustainability. Achieving operational sustainability is a means that may help airports on sustainable development and has positive impacts on airports’ economic viability, natural resource conservation, and social responsibility. However, airport operational sustainability is rarely defined in a consistent, measurable manner (Johnson & Gu, 2017).</p><p><br></p><p>This study explored the understanding of airport operational sustainability among five GA Regional and Local airports. Based on the findings, a new definition of airport operational sustainability for U.S Regional and Local GA airports was proposed. A set of performance metrics for airport operational sustainability was developed. The outcomes of the study may help airport shareholders contribute to airport sustainability planning through a better understanding of sustainability principles<a>. A set of performance metrics for airport operational sustainability </a>may be used to quantify the sustainability achievements of airports and help airports measure their performance.</p><p></p>
24

Investigating the Threats of Unmanned Aircraft Systems (UAS) at Airports

Cheng Wang (9745922) 15 December 2020 (has links)
Safety is the top priority for the aviation industry and a safe airport environment is essential to aviation safety. However, due to the increasing prevalence of UAS in recent years, UAS sightings have become a potential threat to airports. When UAS appear in the vicinity of airports, they bring safety concerns and result in negative operational and economic impacts on airports. Since the FAA’s mission is to provide the safest and most efficient aerospace system in the world, further research regarding the threat of UAS sightings to airports is needed. The purpose of this study is to investigate the threat of UAS to airports and in the national airspace system (NAS). This study includes three primary components: the analysis of 6,551 Federal Aviation Administration (FAA) UAS sighting reports, a case study of the impacts of the UAS sighting at Newark Liberty International Airport (EWR) on January 22, 2019, and a synthesis of airport operator perspectives based on interviews with airport personnel at five airports. The analysis of UAS sighting reports shows the characteristics of UAS sightings, the case study on EWR UAS illustrates the impact of the UAS sighting at the airport, and interview results illustrate the current perspective of airport operators regarding the risk of UAS. Along with the results, the scientific methods of identifying and analyzing the characteristics of UAS sightings in controlled airspace close to airports could be used by researchers to study UAS sightings in the future. Findings from this study may be beneficial to multiple stakeholders, including airport personnel, regulators, entrepreneurs, and vendors in the aviation industry. <br>
25

A NETWORK LEVEL FEASIBILITY FRAMEWORK FOR BEAM-POWERED AIRCRAFT

Ethan Charles Wright (15342052) 24 April 2023 (has links)
<p>Beam-powered aircraft are a promising solution to reducing the air transportation system's operating costs and emissions due to their reliance on typically more efficient ground-based electricity sources.</p> <p>However, modeling these aircraft is a non-trivial task due to their multi-disciplinary nature and the required interconnectedness between the aircraft, air transportation network, and power-beaming models.</p> <p><br></p> <p>This thesis establishes a methodology for holistically modeling beam-powered aircraft as a freight transportation asset in the context of their operating environment.</p> <p>This methodology accounts for elements of aircraft conceptual design, the limits of power-beaming technology, and non-idealities associated with the air transportation network.</p> <p>As a product of this methodology, this thesis also approximates beam-powered aircraft's economic and environmental feasibility based on current and future technological capabilities.</p> <p><br></p> <p>This work concludes that with an optimistic enough "engine absent" mass fraction and with sufficiently advanced technologies -- particularly with higher power density rectennas -- beam-powered aircraft are both economically and environmentally feasible, having a lower operating cost and emitting less carbon dioxide per ton-mile compared to current-day and near-future freight transportation aircraft.</p> <p><br></p> <p>More specifically, this work concludes that when using a simplified and more optimistic engine absent mass fraction model, power train specific power only needs to improve by a factor of 1.2-3.7 and rectenna power density only needs to improve by a factor of 20-30 compared to the baseline technologies considered in this work in order for beam-powered aircraft to be a feasible alternative to jet fuel powered aircraft in a freight transportation role.</p> <p>However, with a more pessimistic albeit more realistic engine absent mass fraction model, this work concludes that beam-powered aircraft are not feasible in a freight transportation role with the technology levels considered in this work.</p>
26

The Control of Air Transportation of Small Arms and Light Weapons and Munitions: A Comparative Study of National Systems Utilised in the European Union

Greene, Owen J. 03 1900 (has links)
No / A major original research project, commissioned by France (Ministry of Defence), to contribute to an EU (and also an international), policy process to prevent and combat illegal SALW transfers during transit. Greene was co-director and a core researcher for this project, playing a leading role in its design, field work, and analysis. Involved substantial interviews and engagement with EU and Eastern European governments, customs, air transport control and other authorities; presented at a cross-governmental workshop for the French Government and for European Commission, and extensively used in the subsequent policy process.
27

An Agent-based Model for Airline Evolution, Competition, and Airport Congestion

Kim, Junhyuk 07 July 2005 (has links)
The air transportation system has grown significantly during the past few decades. The demand for air travel has increased tremendously as compared to the increase in the supply. The air transportation system can be divided into four subsystems: airports, airlines, air traffic control, and passengers, each of them having different interests. These subsystems interact in a very complex way resulting in various phenomena. On the airport side, there is excessive flight demand during the peak hours that frequently exceeds the airport capacity resulting in serious flight delays. These delays incur costs to the airport, passengers, and airlines. The air traffic pattern is also affected by the characteristics of the air transportation network. The current network structure of most major airlines in United States is a hub-and-spoke network. The airports are interested in reducing congestion, especially during the peak time. The airlines act as direct demand to the airport and as the supplier to the passengers. They sometimes compete with other airlines on certain routes and sometimes they collaborate to maximize revenue. The flight schedule of airlines directly affects the travel demand. The flight schedule that minimizes the schedule delay of passengers in directed and connected flights will attract more passengers. The important factors affecting the airline revenue include ticket price, departure times, frequency, and aircraft type operated on each route. The revenue generated from airline depends also on the behavior of competing airlines, and their flight schedules. The passengers choose their flight based on preferred departure times, offered ticket prices, and willingness of airlines to minimize delay and cost. Hence, all subsystems of air transportation system are inter-connected to each other, meaning, strategy of each subsystem directly affects the performance of other subsystems. This interaction between the subsystems makes it more difficult to analyze the air transportation system. Traditionally, analytical top-down approach has been used to analyze the air transportation problem. In top-down approach, a set of objectives is defined and each subsystem is fixed in the overall scheme. On the other hand, in a bottom-up approach, many issues are addressed simultaneously and each individual system has greater autonomy to make decisions, communicate and to interact with one another to achieve their goals when considering complex air transportation system. Therefore, it seems more appropriate to approach the complex air traffic congestion and airline competition problems using a bottom-up approach. In this research, an agent-based model for the air transportation system has been developed. The developed model considers each subsystem as an independent type of agent that acts based on its local knowledge and its interaction with other agents. The focus of this research is to analyze air traffic congestion and airline competition in a hub-and-spoke network. The simulation model developed is based on evolutionary computation. It seems that the only way for analyzing emergent phenomenon (such as air traffic congestion) is through the development of simulation models that can simulate the behavior of each agent. In the agent-based model developed in this research, agents that represent airports can increase capacity or significantly change landing fee policy, while the agents that represent airlines learn all the time, change their markets, fare structure, flight frequencies, and flight schedules. Such a bottom-up approach facilitates a better understanding of the complex nature of congestion and gains more insights into the competition in air transportation, hence making it easier to understand, predict and control the overall performance of the complex air transportation system. / Ph. D.
28

Enhanced Air Transportation Modeling Techniques for Capacity Problems

Spencer, Thomas Louis 02 September 2016 (has links)
Effective and efficient air transportation systems are crucial to a nation's economy and connectedness. These systems involve capital-intensive facilities and equipment and move millions of people and tonnes of freight every day. As air traffic has continued to increase, the systems necessary to ensure safe and efficient operation will continue to grow more and more complex. Hence, it is imperative that air transport analysts are equipped with the best tools to properly predict and respond to expected air transportation operations. This dissertation aims to improve on those tools currently available to air transportation analysts, while offering new ones. Specifically, this thesis will offer the following: 1) A model for predicting arrival runway occupancy times (AROT); 2) a model for predicting departure runway occupancy times (DROT); and 3) a flight planning model. This thesis will also offer an exploration of the uses of unmanned aerial vehicles for providing wireless communications services. For the predictive models of AROT and DROT, we fit hierarchical Bayesian regression models to the data, grouped by aircraft type using airport physical and aircraft operational parameters as the regressors. Recognizing that many existing air transportation models require distributions of AROT and DROT, Bayesian methods are preferred since their output are distributions that can be directly inputted into air transportation modeling programs. Additionally, we exhibit how analysts will be able to decouple AROT and DROT predictions from the traditional 4 or 5 groupings of aircraft currently in use. Lastly, for the flight planning model, we present a 2-D model using presently available wind data that provides wind-optimal flight routings. We improve over current models by allowing free-flight unconnected to pre-existing airways and by offering finer resolutions over the current 2.5 degree norm. / Ph. D.
29

General Aviation Demand Forecasting Models and a Microscopic North Atlantic Air Traffic Simulation Model

Li, Tao 06 January 2015 (has links)
This thesis is focused on two topics. The first topic is the General Aviation (GA) demand forecasting models. The contributions to this topic are three fold: 1) we calibrated an econometric model to investigate the impact of fuel price on the utilization rate of GA piston engine aircraft, 2) we adopted a logistic model to identify the relationship between fuel price and an aircraft's probability of staying active, and 3) we developed an econometric model to forecast the airport-level itinerant and local GA operations. Our calibration results are compared with those reported in literature. Demand forecasts are made with these models and compared with those prepared by the Federal Aviation Administration. The second topic is to model the air traffic in the Organized Track System (OTS) over the North Atlantic. We developed a discrete-time event model to simulate the air traffic that uses the OTS. We proposed four new operational procedures to improve the flight operations for the OTS. Two procedures aim to improve the OTS assignments in the OTS entry area, and the other two aim to benefit flights once they are inside the OTS. The four procedures are implemented with the simulation model and their benefits are analyzed. Several implementation issues are discussed and recommendations are given. / Ph. D.
30

Terrorisme international et mesures de sûreté : analyse économique du comportement du voyageur sur le réseau de transport aérien mondial / International terrorism and security measures : economic analysis of the traveler’s behavior on the global air transportation network

Depigny, Marine 27 September 2011 (has links)
Dans cette thèse, nous questionnons l’impact du terrorisme international et des mesures de sûreté sur le comportement des usagers du réseau de transport aérien mondial. A l’aide d’un modèle économétrique, nous analysons une base de données inédite, AirNetTerror, composée de l’ensemble des vols internationaux à destination des Etats-Unis de 1990 à 2006, et des données du terrorisme international par pays sur cette période. La pertinence de notre travail est double. D’une part, nos interrogations sur les comportements des voyageurs et leurs éventuelles substitutions d’itinéraires en lien avec le terrorisme international n’ont, à notre connaissance, jamais été traitées. D’autre part, en abordant le transport aérien sous l’angle du réseau, nous proposons une vision dynamique des répercussions des comportements des usagers en lien avec la menace terroriste et les mesures de sûreté. En particulier, la prise en compte de la situation de sûreté interdépendante régissant le réseau aérien mondial nous permet de questionner l’existence de failles dans les mesures de sûreté. Nos résultats soulignent l’impact avéré et significatif des événements du terrorisme international, mais aussi des mesures de sûreté sur le réseau de transport aérien mondial. De plus, nous observons localement des substitutions d’itinéraires des voyageurs aériens en lien avec ces phénomènes. Ainsi, l’effet combiné de la menace terroriste internationale et des mesures de sûreté semble être à l’origine de ruptures d’équilibre, certes limitées mais réelles, des flux de passagers du réseau de transport aérien mondial. Notre thèse, parce qu’elle place le comportement du voyageur au centre des interactions stratégiques entre les acteurs de la sûreté et les terroristes, permet d’apporter une vision inédite de l’impact du terrorisme international sur le transport aérien. / In our dissertation, we question the impact of both international terrorism and security measures on the behavior of the users of the global air transportation network. Using an econometric model, we analyze a new database, AirNetTerror, which contains data on all international passenger flows toward the U.S. from 1990 to 2006 as well as the events of international terrorism by country for the same period. The relevance of our research is twofold. On the one hand, our investigation regarding air travelers’ behavior and their possibilities of modifying their itinerary in light of international terrorism has – so far as we know – never been studied. On the other hand, as we analyze passenger flows from the perspective of the network, we propose a dynamic representation of the impact of travelers’ behavior changes related to terrorist threats and security measures. In particular, taking into account the interdependent security that rules the global air transport network, allows us to question the existence of failures in security measures. Our results underline a significant impact of both international terrorist events and security measures. Furthermore, we locally observe itinerary modifications of travelers that are linked to the previous phenomena. Thus, the combined effect of terrorist threats and security measures seems to lead to equilibrium breaks – that are limited but real – in passenger flows of the global air network. Our thesis offers a different representation of the impact of international terrorism on air transport by placing the traveler’s behavior at the center of the strategic interactions between security actors and terrorists.

Page generated in 0.1711 seconds