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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Computational air traffic management

Azzopardi, Marc Anthony January 2015 (has links)
World air transport has been on a steady exponential rise since the 1940’s and the trend has shown remarkable resilience to external shocks. The level of air traffic has greatly exceeded the wildest expectations of the air traffic management pioneers that originally defined the basic precepts ATM that persist till today. This has stretched ATM to a point where it is starting to show signs of ineffectiveness in the face of ever increasing congestion. Delays are on the rise, costs are ballooning, flights are being elongated unnecessarily, the system is becoming increasingly susceptible to disruption, and the high environmental impact of aviation is being compounded by the inability of air traffic controllers to optimise ATM operation in real-time. If these trends are not reversed, ATM could eventually face instability. The conservative, self-preserving outlook of the ATM community has confined progress to relatively minor tweaks of a tired human-centric paradigm. However, the diverging gap between ATM performance and fundamental requirements indicates the need for a step change. In this work, the traditionally incremental approach to ATM research was broken to favour a more exploratory mindset. As a result, a new discipline called Computational Air Traffic Management has been defined to address the unique set of challenges presented by the ATM problem, by taking a more objective scientific approach. A specific embodiment of a CATM system was designed, constructed, simulated and tested and shown to be a significant step towards demonstrating the feasibility of a fully autonomous multi-agent-based air transportation system based on optimisation principles. The system offers unique advantages in terms of resilience to disruption, efficiency and future scalability. The traffic density using such a system can be realistically increased many times higher than current levels while significantly improving on the current levels of safety, operating cost, environmental impact and flight delays. This work advances the field of ATM as well as the fields of Computational Intelligence and Dynamic Optimisation of High Dimensionality Non- Convex Search Spaces.
2

On the utilization of aircraft derived observations for operational meteorology and numerical weather prediction

Mirza, Andrew Karl January 2017 (has links)
This thesis analyses a new source of observations, Mode-Select Enhanced Surveillance (Mode-S EHS), obtained from reports exchanged between aircraft and air-traffic control. These reports contain the aircrafts speed, direction, altitude and Mach number. Observations of temperature and horizontal wind can be derived from the reports. However, Mode-S EHS processing reduces the reporting precision from 16-bit to 10-bit representation. We aim to understand the observation errors that are due to the reduced precision of Mode-S EHS reports, how accurately these derived observations represent vertical profiles of wind and temperature and the benefit they bring to convection-permitting NWP. We derive new models to estimate the observation errors and validate them using research grade instruments on board the Facility for Atmospheric Airborne Measurements. For the cases studied, the temperature observation error increases from 1.25 K to 2.5 K between an altitude of 10 km and the surface, due to its dependence on Mach number and Mode-S EHS precision. The zonal wind error is around 0.50 ms−1 and the meridional wind error is 0.25 ms−1. The horizontal wind is also subject to directionally dependent systematic errors. We aggregate Mode-S EHS reports from multiple aircraft to construct vertical pro- files of temperature and demonstrate their ability to resolve temperature inversions. However, there are large errors in the aggregated observations that are still dominated by the effects of reduced precision. We assess the benefits of Mode-S EHS for data assimilation in the Met Office convection-permitting NWP model. We find that assimilation of Mode-S EHS has a neutral impact. Using assimilation output statistics, we find that the observation uncertainties for AMDAR and Mode-S EHS horizontal wind are similar in magnitude, while for Mode-S EHS Mach temperature the diagnosed errors are similar to our new error model. Our new results may assist with utilising Mode-S EHS reports in operational forecasting.
3

Collaborative decision making in complex work settings : a process of managing inter dependencies

Selvaraj, Nallini January 2016 (has links)
There exists disparity between the conceptualization and occurrence of Collaborative Decision Making (CDM) in everyday work activities of complex work settings. Current notions in the field of Computer Supported Cooperative Work (CSCW) based on studies of decision making in groups typically portray CDM as an isolated event in which multiple personnel jointly undertake decision making. In the real world, however, decisions are made during work performance and interlaced with other processes and activities. Moreover, the complex work setting is a cooperative arrangement in which decision making is distributed. This research aims to alleviate the disparity by investigating how people in a complex working environment make decisions collaboratively. The original contribution to knowledge made by this thesis is the theory of CDM as a process of managing interdependencies. Field-studies conducted in an airport to examine the way CDM is undertaken during Air Traffic Control operations inform theory development. The study takes a qualitative approach and is guided by Grounded Theory Methodology (GTM). The findings of this research indicate that undertaking decision making in the cooperative arrangement of complex work settings requires managing the distributions and interconnections inherent in this setup. In addition, participation and contribution of personnel in decision making is found to be structured by the dependencies between their activities. These findings form the central focus of the theory leading to the depiction of CDM as a process of managing interdependencies. The theory presented in this thesis clarifies and extends existing views by explicating the differentiated process of CDM in the cooperative arrangement of a complex work setting. Based on this a new definition of CDM is formulated. In addition, a conceptual framework of ten parameters is derived to serve as a tool for analysing CDM taking place in a particular work setting. Application of this framework is demonstrated by analysing an aircraft accident report to draw insights about the occurrence of CDM in this setting.
4

The organisational precursors to human automation interaction issues in safety-critical domains : the case of an automated alarm system from the air traffic management domain

Rozzi, Simone January 2016 (has links)
Much has been written about the side effects of automation in complex safety-critical domains, such as air traffic management, aviation, nuclear power generation, and healthcare. Here, human factors and safety researchers have long acknowledged that the potential of automation to increase cost-effectiveness, quality of service and safety, is accompanied by undesired side effects or issues in human automation interaction (HAI). Such HAI issues may introduce the potential for increased confusion, uncertainty, and frustration amongst sharp end operators, i.e. the users of automation. These conditions may result in operators to refuse to use the automation, in impaired ability of operators to control the hazardous processes for which they are responsible, and in new, unintended paths to safety failure. The present thesis develops a qualitative framework of the organisational precursors to HAI issues (OPHAII) that can be found in safety-critical domains. Organisational precursors denote those organisational and managerial conditions that, although distant in time and space from the operational environment, may actually influence the quality of HAI found there. Such precursors have been extensively investigated by organisational safety (OS) scholars in relation to the occurrence of accidents and disasters—although not HAI issues. Thus, the framework’s development is motivated by the intent to explore the theoretical gap lying at the intersection between the OS area and the current perspectives on the problem—the human computer interaction (HCI) and the system lifecycle ones. While considering HAI issues as a design problem or a failure in human factors integration and/or safety assurance respectively, both perspectives, in fact, ignore, the organisational roots of the problem. The OPHAII framework was incrementally developed based on three qualitative studies: two successive, historical, case studies coupled with a third corroboratory expert study. The first two studies explored the organisational precursors to a known HAI issue: the nuisance alert problem relative to an automated alarm system from the air traffic management domain. In particular, the first case study investigated retrospectively the organisational response to the nuisance alert problem in the context of the alarm’s implementation and improvement in the US between 1977 and 2006. The second case study has a more contemporary focus, and examined at the organisational response to the same problem within two European Air Navigation Service Providers between 1990 and 2010. The first two studies produced a preliminary version of the framework. The third study corroborated and refined this version by subjecting it to the criticism from a panel of 11 subject matter experts. The resulting framework identifies three classes of organisational precursors: (i) the organisational assumptions driving automation adoption and improvement; (2) the availability of specific organisational capabilities for handling HAI issues; and (3) the control of implementation quality at the boundary between the service provider and the software manufacturer. These precursors advance current understanding of the organisational factors involved in the (successful and problematic) handling of HAI issues within safety-critical service provider organisations. Its dimensions support the view that HAI issues can be seen as and organisational phenomenon—an organisational problem that can be the target of analysis and improvements complementary to those identified by the HCI and the system lifecycle perspectives.
5

Developing a framework for total apron safety management

Studic, Milena January 2015 (has links)
The Air Traffic Management (ATM) system is a complex socio-technical system that ensures safe, efficient and cost-effective air traffic movements on the ground and in the air. The current ATM system is saturated as a result of an everlasting growth in air travel demand, leading to delays and potential negative safety impacts. In order to meet future demand, current ATM modernisation initiatives in the European Union and the USA are developing a new concept of operations based on strategic holistic system optimisation. On the airport surface, this is achieved by optimising operations not only during the take-off, landing and taxiing phases, but also during the turnaround process on the apron. This requires the boundary of the ATM system to expand to include new elements, namely the apron. A key deficiency in current initiatives is that, while they focus on capacity, punctuality and cost-effectiveness of the apron, they do not address safety. This has potential negative impacts in terms of setting and prioritising safety targets. Unlike the rest of the aviation domain, which is aircraft-centric, the concept of apron safety is much wider and in addition to aircraft safety, it also includes occupational health and safety. Recent aviation safety statistics show that aircraft accidents attributed to ground handling operations are six times more frequent than those attributed to the ATM. Additionally, the UK Health and Safety Executive (HSE) statistics show worse safety records on the apron when compared to the construction and agricultural industries. Considering the change in the ATM system boundary and the low aviation and occupational health and safety records, the airport apron has been identified in this thesis as a new safety-critical area of the future ATM system. Therefore, a key focus of this thesis is to address current deficiencies with respect to safety management on the apron, by developing a better understanding of the processes carried out on the apron and a new framework for safety assessment, as well as recommending enhancements to existing safety management practices. In contrast to existing safety management practices that are based on a dated understanding of safety (referred to as Safety-I), which is predominantly reactive, the framework proposed in this thesis, for the first time, adopts a state-of-the-art proactive and predictive understanding of safety (referred to as Safety-II) for the apron. The thesis demonstrates for the first time that the existing linear component-based models traditionally used for modelling apron safety do not account for the system complexity. Therefore, the proposed framework develops a state-of-the-art systemic functional Total Apron Safety Management (TASM) model and a corresponding taxonomy of factors that characterise different sources of variability of ground handling services, capable of accounting for dependencies and dynamic interactions between different layers of the apron system (i.e. technological, human and organisational). The proposed functional model and taxonomy have been applied to three case studies in retrospective, prospective and system design analysis demonstrating the multi-purposive nature of the framework, particularly important under existing financial pressures. In retrospective analysis the proposed functional model and taxonomy have shown to identify systemic factors previously not found during the occurrence investigation. In prospective analysis, a new protocol for systemic and systematic hazard analysis in complex socio-technical systems (including the apron) was developed. Furthermore, a novel conceptual framework for a safety trend analysis based on the TASM framework was developed, offering a quick, simple, cost-effective analysis of large datasets. A key advantage of the TASM framework is that it is transferable to all ground handling services carried out by Ground Service Providers (GSP), airlines and/or airports.
6

Investigation on soft computing techniques for airport environment evaluation systems

Yang, Yingjie January 2008 (has links)
Spatial and temporal information exist widely in engineering fields, especially in airport environmental management systems. Airport environment is influenced by many different factors and uncertainty is a significant part of the system. Decision support considering this kind of spatial and temporal information and uncertainty is crucial for airport environment related engineering planning and operation. Geographical information systems and computer aided design are two powerful tools in supporting spatial and temporal information systems. However, the present geographical information systems and computer aided design software are still too general in considering the special features in airport environment, especially for uncertainty. In this thesis, a series of parameters and methods for neural network-based knowledge discovery and training improvement are put forward, such as the relative strength of effect, dynamic state space search strategy and compound architecture.
7

Economic aspects of the Spanish airports

Echevarne, R. January 1995 (has links)
No description available.
8

Disaggregate behavioural airport choice models

Benchemam, Messaoud January 1986 (has links)
The identification of the distribution of air passengers among airports is an important task of the airport planner. It would be useful to understand how trip makers choose among competing airports. The ultimate purpose of this study is to research into , passengers' choice of airport so that the airport system can be planned on a more reliable basis. The choice of airport of passengers originating from central England in 1975 is explained by constructing multinomial disaggregate behavioural models of logit form. The data used for model calibration, were collected during two Civil Aviation Authority surveys. This work makes contribution to: -The definition of the major determinants of airport choice, -The responsiveness of passengers, choice to changes in these determinants, - The policy implications for the regional airports - The transferability of the model in time and space. The method of analysis has been selected after outlining the potential advantages and shortcomings of logit and probit models and after a test on the validity of the Independence from Irrelevant Alternatives (I.I.A.) property has been carried out. The results show that the multinomial logit model used for the airport choice is good in terms of its explanatory ability and successful in predicting the choices actually made. Travel time to the airport, frequency of flights and air fare are found to be decisive factors for a passenger to select a given airport but are not of equal importance. By influencing-these factors, it appears that there exists room for the transport planner to shift traffic from one airport to another to have an economically and/or environmentally efficient airport system. In their original form, the models have been tested and found not to be transferable to the London area in 1978. However, after a Bayesian updating procedure was applied, the business and inclusive tours models were transferable. The leisure model was not statistically transferable but had a good predictive ability while the domestic model was not transferable. Finally, subsequent directions ·for further research are outlined.
9

The strategic management of projects to enhance value for money for BAA plc

Bell, Kathryn L. January 1994 (has links)
The airport business is undergoing a shift from that of a traditionally operational nature, to a more commercial, profit driven business orientation. Airport infrastructure is experiencing a face lift in order to meet the requirements for customer satisfaction resulting from this shift in culture. In this regard airport operators must seek improvements in the way in which their development projects are planned, designed and delivered. An inherent link between corporate, business and project value, highlighted within this thesis, has led to the requirement for project management systems that maximise value and therefore facilitate the corporate strategy of the organisation. This thesis develops a model to strategically manage projects to enhance value for money for BAA plc. It is concluded that the project management process is divided into two primary phases: the strategic and tactical, the former receiving minimum attention in UK construction project management. By combining the strategic management of a portfolio of projects with the tactical management of individual projects a link is forged between corporate and customer value and project value. The thesis concludes by presenting the Strategic Project Management framework for use by BAA project managers. The decision making framework facilitates the definition of project objectives and manages the project process to realise optimum value to the client / customer groups. By defining sub processes within the overall project process, the framework binds the interfaces such that information and communication flows freely and completely through the project.
10

Airport access and travel time uncertainty

Taylor, Robin January 1996 (has links)
The implications of travel time uncertainty on the operational efficiency of airport terminals have until now not been examined. With the forecast growth in congestion levels predicted for all modes of transport, not only will travel time uncertainty increase but its impact may increase also. The first part of this thesis covers the analysis of two passenger surveys conducted at Manchester Airport and Birmingham Airport. These surveys had the objective of providing evidence to support or dispute the belief that air travellers react to travel time uncertainty. The research identifies that passengers do react by allowing margins of safety for their access journeys, and that this change in behaviour will modify the arrival distribution patterns at airports. The second part of this thesis examines how airport passenger flows could be altered by a change in the arrival distribution of originating passengers at airport terminals. Three airports - Manchester, Birmingham and East Midlands International - are modelled using a simulation tool and tested to assess how a shift in arrival distribution affects queuing and peak passenger volumes within the airport terminal. The findings of this thesis show that airport passenger terminal operational efficiency is affected by access journey time uncertainty. It also identifies that passenger decision making can only be explained by various combinations of factors. Possible methods of minimising the effects of travel time uncertainty are considered. The advantages and disadvantages of access journey time uncertainty for airports and airlines are discussed. It concludes that, to be successful in overcoming negative aspects, both parties must provide a service that results in customer satisfaction. This is the only sure way to maintain their respective revenue levels and secure their future in what is becoming an increasingly competitive industry.

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