A Hybrid Tabu/Scatter Search Algorithm for Simulation-Based Optimization of Multi-Objective Runway Operations Scheduling

As air traffic continues to increase, air traffic flow management is becoming more challenging to effectively and efficiently utilize airport capacity without compromising safety, environmental and economic requirements. Since runways are often the primary limiting factor in airport capacity, runway operations scheduling emerge as an important problem to be solved to alleviate flight delays and air traffic congestion while reducing unnecessary fuel consumption and negative environmental impacts. However, even a moderately sized real-life runway operations scheduling problem tends to be too complex to be solved by analytical methods, where all mathematical models for this problem belong to the complexity class of NP-Hard in a strong sense due to combinatorial nature of the problem. Therefore, it is only possible to solve practical runway operations scheduling problem by making a large number of simplifications and assumptions in a deterministic context. As a result, most analytical models proposed in the literature suffer from too much abstraction, avoid uncertainties and, in turn, have little applicability in practice. On the other hand, simulation-based methods have the capability to characterize complex and stochastic real-life runway operations in detail, and to cope with several constraints and stakeholders’ preferences, which are commonly considered as important factors in practice. This dissertation proposes a simulation-based optimization (SbO) approach for multi-objective runway operations scheduling problem. The SbO approach utilizes a discrete-event simulation model for accounting for uncertain conditions, and an optimization component for finding the best known Pareto set of solutions. This approach explicitly considers uncertainty to decrease the real operational cost of the runway operations as well as fairness among aircraft as part of the optimization process. Due to the problem’s large, complex and unstructured search space, a hybrid Tabu/Scatter Search algorithm is developed to find solutions by using an elitist strategy to preserve non-dominated solutions, a dynamic update mechanism to produce high-quality solutions and a rebuilding strategy to promote solution diversity. The proposed algorithm is applied to bi-objective (i.e., maximizing runway utilization and fairness) runway operations schedule optimization as the optimization component of the SbO framework, where the developed simulation model acts as an external function evaluator. To the best of our knowledge, this is the first SbO approach that explicitly considers uncertainties in the development of schedules for runway operations as well as considers fairness as a secondary objective. In addition, computational experiments are conducted using real-life datasets for a major US airport to demonstrate that the proposed approach is effective and computationally tractable in a practical sense. In the experimental design, statistical design of experiments method is employed to analyze the impacts of parameters on the simulation as well as on the optimization component’s performance, and to identify the appropriate parameter levels. The results show that the implementation of the proposed SbO approach provides operational benefits when compared to First-Come-First-Served (FCFS) and deterministic approaches without compromising schedule fairness. It is also shown that proposed algorithm is capable of generating a set of solutions that represent the inherent trade-offs between the objectives that are considered. The proposed decision-making algorithm might be used as part of decision support tools to aid air traffic controllers in solving the real-life runway operations scheduling problem

A Robust Scalable Transportation System Concept

This report documents the 2005 Revolutionary System Concept for Aeronautics (RSCA) study entitled "A Robust, Scalable Transportation System Concept". The objective of the study was to generate, at a high-level of abstraction, characteristics of a new concept for the National Airspace System, or the new NAS, under which transportation goals such as increased throughput, delay reduction, and improved robustness could be realized. Since such an objective can be overwhelmingly complex if pursued at the lowest levels of detail, instead a System-of-Systems (SoS) approach was adopted to model alternative air transportation architectures at a high level. The SoS approach allows the consideration of not only the technical aspects of the NAS", but also incorporates policy, socio-economic, and alternative transportation system considerations into one architecture. While the representations of the individual systems are basic, the higher level approach allows for ways to optimize the SoS at the network level, determining the best topology (i.e. configuration of nodes and links). The final product (concept) is a set of rules of behavior and network structure that not only satisfies national transportation goals, but represents the high impact rules that accomplish those goals by getting the agents to "do the right thing" naturally. The novel combination of Agent Based Modeling and Network Theory provides the core analysis methodology in the System-of-Systems approach. Our method of approach is non-deterministic which means, fundamentally, it asks and answers different questions than deterministic models. The nondeterministic method is necessary primarily due to our marriage of human systems with technological ones in a partially unknown set of future worlds. Our goal is to understand and simulate how the SoS, human and technological components combined, evolve

Evaluating Network Analysis and Agent Based Modeling for Investigating the Stability of Commercial Air Carrier Schedules

For a number of years, the United States Federal Government has been formulating the Next Generation Air Transportation System plans for National Airspace System improvement. These improvements attempt to address air transportation holistically, but often address individual improvements in one arena such as ground or in-flight equipment. In fact, air transportation system designers have had only limited success using traditional Operations Research and parametric modeling approaches in their analyses of innovative operations. They need a systemic methodology for modeling of safety-critical infrastructure that is comprehensive, objective, and sufficiently concrete, yet simple enough to be deployed with reasonable investment. The methodology must also be amenable to quantitative analysis so issues of system safety and stability can be rigorously addressed

Human performance and strategies while solving an aircraft routing and sequencing problem: an experimental approach

As airport resources are stretched to meet increasing demand for services, effective use of ground infrastructure is increasingly critical for ensuring operational efficiency. Work in operations research has produced algorithms providing airport tower controllers with guidance on optimal timings and sequences for flight arrivals, departures, and ground movement. While such decision support systems have the potential to improve operational efficiency, they may also affect users’ mental workload, situation awareness, and task performance. This work sought to identify performance outcomes and strategies employed by human decision makers during an experimental airport ground movement control task with the goal of identifying opportunities for enhancing user-centered tower control decision support systems. To address this challenge, thirty novice participants solved a set of vehicle routing problems presented in the format of a game representing the airport ground movement task practiced by runway controllers. The games varied across two independent variables, network map layout (representing task complexity) and gameplay objective (representing task flexibility), and verbal protocol, visual protocol, task performance, workload, and task duration were collected as dependent variables. A logistic regression analysis revealed that gameplay objective and task duration significantly affected the likelihood of a participant identifying the optimal solution to a game, with the likelihood of an optimal solution increasing with longer task duration and in the less flexible objective condition. In addition, workload appeared unaffected by either independent variable, but verbal protocols and visual observations indicated that high-performing participants demonstrated a greater degree of planning and situation awareness. Through identifying human behavior during optimization problem solving, the work of tower control can be better understood, which, in turn, provides insights for developing decision support systems for ground movement management

Collaborative rescheduling of flights in a single mega-hub network

Traditionally, airlines have configured flight operations into a Hub and Spoke network design. Using connecting arrival departure waves at multiple hubs these networks achieve efficient passenger flows. Recently, there has been much growth in the development of global single mega-hub (SMH) flight networks that have a significantly different operating cost structure and schedule design. These are located primarily in the Middle East and are commonly referred to as the ME3. The traditionalist view is that SMH networks are money losers and subsidized by sovereign funds. This research studies and analyzes SMH networks in an attempt to better understand their flight efficiency drivers. Key characteristics of SMH airports are identified as: (i) There are no peak periods, and flight activity is balanced with coordinated waves (ii) No priority is assigned to arrival/departure times at destinations (selfish strategy) only hub connectivity is considered (iii) There is less than 5% OD traffic at SMH (iv) The airline operates only non-stop flights (v) Passengers accept longer travel times in exchange for economic benefits (vi) Airline and airport owners work together to achieve collaborative flight schedules. This research focuses on the network structure of SMH airports to identify and optimize the operational characteristics that are the source of their advantages. A key feature of SMH airports is that the airline and airport are closely aligned in a partnership. To model this relationship, the Mega-Hub Collaborative Flight Rescheduling (MCFR). Problem is introduced. The MCFR starts with an initial flight schedule developed by the airline, then formulates a cooperative objective which is optimized iteratively by a series of reschedules. Specifically, in a network of iEM cities, the decision variables are i* the flight to be rescheduled, Di* the new departure time of flight to city i* and Hi* the new hold time at the destinatioin city i*. The daily passenger traffic is given by Ni,j and normally distributed with parameters µNi,j and sNi,j. A three-term MCFR objective function is developed to represent the intersecting scheduling decision space between airlines and airports: (i) Passenger Waiting Time (ii) Passenger Volume in Terminal, and (iii) Ground Activity Wave Imbalance. The function is non-linear in nature and the associated constraints and definitions are also non-linear. An EXCEL/VBA based simulator is developed to simulate the passenger traffic flows and generate the expected cost objective for a given flight network. This simulator is able to handle up to an M=250 flight network tracking 6250 passenger arcs. A simulation optimization approach is used to solve the MCFR. A Wave Gain Loss (WGL) strategy estimates the impact Zi of flight shift Δi on the objective. The WGL iteratively reschedules flights and is formulated as a non-linear program. It includes functions to capture the traffic affinity driven solution dependency between flights, the relationship between passengers in terminal gradients and flight shifts, and the relationship between ground traffic activity gradients and flight shifts. Each iteration generates a Zi ranked list of flights. The WGL is integrated with the EXCEL/VBA simulator and shown to generate significant costs reduction in an efficient time. Extensive testing is done on a set of 5 flight network problems, each with 3 different passengers flow networks characterized by low, medium and high traffic concentrations

\u3ci\u3eThe Conference Proceedings of the 2003 Air Transport Research Society (ATRS) World Conference, Volume 5\u3c/i\u3e

UNOAI Report 03-9https://digitalcommons.unomaha.edu/facultybooks/1126/thumbnail.jp

N+3 Small Commercial Efficient and Quiet Transportation for Year 2030-2035

This study develops a future scenario that enables convenient point-to-point commercial air travel via a large network of community airports and a new class of small airliners. A network demand and capacity study identifies current and future air travel demands and the capacity of this new network to satisfy these demands. A current technology small commercial airliner is defined to meet the needs of the new network, as a baseline for evaluating the improvement brought about by advanced technologies. Impact of this new mode of travel on the infrastructure and surrounding communities of the small airports in this new N+3 network are also evaluated. Year 2030-2035 small commercial airliner technologies are identified and a trade study conducted to evaluate and select those with the greatest potential for enhancing future air travel and the study metrics. The selected advanced air vehicle concept is assessed against the baseline aircraft, and an advanced, but conventional aircraft, and the study metrics. The key technologies of the selected advanced air vehicle are identified, their impact quantified, and risk assessments and roadmaps defined

Share the Sky: Concepts and Technologies That Will Shape Future Airspace Use

The airspace challenge for the United States is to protect national sovereignty and ensure the safety and security of those on the ground and in the air, while at the same time ensuring the efficiency of flight, reducing the costs involved, protecting the environment, and protecting the freedom of access to the airspace. Many visions of the future NAS hold a relatively near-term perspective, focusing on existing uses of the airspace and assuming that new uses will make up a small fraction of total use. In the longer term, the skies will be filled with diverse and amazing new air vehicles filling our societal needs. Anticipated new vehicles include autonomous air vehicles acting both independently and in coordinated groups, unpiloted cargo carriers, and large numbers of personal air vehicles and small-scale point-to-point transports. These vehicles will enable new capabilities that have the potential to increase societal mobility, transport freight at lower cost and with lower environmental impact, improve the study of the Earth s atmosphere and ecosystem, and increase societal safety and security by improving or drastically lowering the cost of critical services such as firefighting, emergency medical evacuation, search and rescue, border and neighborhood surveillance, and the inspection of our infrastructure. To ensure that uses of the airspace can continue to grow for the benefit of all, a new paradigm for operations is needed: equitably and safely sharing the airspace. This paper is an examination of such a vision, concentrating on the operations of all types of air vehicles and future uses of the National Airspace. Attributes of a long-term future airspace system are provided, emerging operations technologies are described, and initial steps in research and development are recommended

Proceedings of the Air Transportation Management Workshop

The Air Transportation Management (ATM) Workshop was held 31 Jan. - 1 Feb. 1995 at NASA Ames Research Center. The purpose of the workshop was to develop an initial understanding of user concerns and requirements for future ATM capabilities and to initiate discussions of alternative means and technologies for achieving more effective ATM capabilities. The topics for the sessions were as follows: viewpoints of future ATM capabilities, user requirements, lessons learned, and technologies for ATM. In addition, two panel sessions discussed priorities for ATM, and potential contributions of NASA to ATM. The proceedings contain transcriptions of all sessions

Technology Assessment of eVTOL Personal Air Transportation System

This thesis intended to provide a holistic vision on the potential consequences of the introduction of emerging electrical Vertical Takeoff and Landing (e VTOL) Personal Air Transportation System (PATS) to contribute to the forming of public and policy opinion, and to assess the impacts and the feasibility of that. Instead of looking from a detailed vehicle design viewpoint, we tried to understand the need, the impacts, and the perceptions and the concerns of stakeholders. Thus, it was set a framework and methodology starting with a technology assessment point of view in the light of transportation system analysis. Limitations of the current ground and airline transportation systems, increasing congestion, poor block speed, combined with expanding population and demand for affordable on- demand mobility are driving the development of future transportation technology and policy. The third wave of aeronautics might be the answer and could bring about great new capabilities for society that would bring aviation into a new age of being relevant in daily lives since eVTOL PATS is envisioned as the next logical step in the natural progression in the history of disruptive transportation system innovations. However, there are a lot of questions. Although there was difficulty since the system was an emerging air transportation mode, an interdisciplinary study has been conducted to assess the impacts of developing such a capability. The research questions were determined to address the research objectives. What is the current state of mobility and eVTOL air transportation mode? What are the potential benefits of eVTOL air transportation mode for user and society? What are the perceptions of service providers, regulator, and user? What are the main challenges including technology, regulation, operation, social and environment aspects to enable the system? What are the enabling technologies? Nevertheless, with the results obtained lately from the research activities, revolutionary technologies and regulations are bringing us closer to eVTOL PATS reality every day. It can be argued that a new socio-technical transition will come about like the transition from horse drawn carriers to cars. Even if it is still a long way to go, it seems rather likely that the time has been arriving in the next decade. Their existence and operation would therefore need to be taken into consideration for today’s planning considerations and construction projects to be able to have this emerging air transportation mode available in the future. As the technology underlying eVTOL PATS evolves, wider eVTOL adoption across various markets is likely to be supported further if a set of key challenges such as safety and security, ease of use and autonomy, noise, infrastructure, and air traffic management are overcome. Achieving drastic improvements in ease of use, safety and community acceptable noise are the most critical steps towards the future feasibility of this market. Multi-use demos and demonstrating successful operation with early vehicles, namely eVTOL PATS prototype field operations, will create public acceptance and understanding of potentials in emerging air transportation mode for public good, use and learn in multiple applications. The overall perception of the user, service provider and regulator are positive, and the support is high. Shortly, a successful implementation and sustainable transition will depend on overcoming technological hurdles, regulatory frameworks, operational safety, cost competitiveness, and sensibilities of the affected communities. There is a need to enable people and goods to have the convenience of on-demand, point-to-point safe travel, further, anywhere in less travel time, through a network of pocket airports/vertiports, and there is a significant potential benefit so that policy makers, regulators and metropoles’ transportation planning departments should consider an inclusion of eVTOL air transportation mode into the scenarios and policies of the future.Esta tese pretende fornecer uma visão holística sobre as potenciais consequências da introdução do Sistema de Transporte Aéreo Pessoal (PATS) de Decolagem e Pouso Vertical elétrico emergente (e VTOL) para contribuir para a formação de opinião pública e política, e para avaliar os impactos e a viabilidade disso. Em vez de olhar de um ponto de vista detalhado o projeto do veículo, tentamos entender a necessidade, os impactos, as percepções e as preocupações das partes interessadas. Assim, foi definido um quadro e uma metodologia partindo de um ponto de vista de avaliação de tecnologia à luz da análise do sistema de transporte. As limitações dos atuais sistemas de transporte terrestre e aéreo, o aumento do congestionamento, a baixa velocidade do tráfego, combinados com a expansão da população e a mobilidade com procura acessível estão impulsionando o desenvolvimento de futuras tecnologias e políticas de transporte. A terceira onda da aeronáutica pode ser a resposta e pode trazer grandes novas capacidades para a sociedade que trariam a aviação para uma nova era de ser relevante na vida cotidiana, uma vez que o VTOL PATS é visto como o próximo passo lógico na progressão natural na história das inovações disruptivas do sistema de transporte. No entanto, há muitas perguntas. Embora tenha havido dificuldade por se tratar de um modo de transporte aéreo emergente, um estudo interdisciplinar foi realizado para avaliar os impactos do desenvolvimento de tal capacidade. As questões de investigação foram determinadas para atender aos objetivos do projeto. Qual é o estado atual da mobilidade e do modo de transporte aéreo eVTOL? Quais são os benefícios potenciais do modo de transporte aéreo eVTOL para o utilizador e a sociedade? Quais são as percepções dos provedores de serviços, regulador e utilizador? Quais são os principais desafios, incluindo tecnologia, regulamentação, operação, aspectos sociais e ambientais para habilitar o sistema? Quais são as tecnologias facilitadoras? No entanto, com os resultados obtidos ultimamente nas atividades de pesquisa, tecnologias e regulamentações revolucionárias estão nos aproximando cada dia mais da realidade do VTOL PATS. Pode-se argumentar que uma nova transição sócio-técnica ocorrerá como a transição de carruagens puxadas por cavalos para automóveis. Mesmo que ainda seja um longo caminho a percorrer, parece bastante provável que a hora esteja chegando na próxima década. A sua existência e operação, portanto, precisam ser levadas em consideração para as questões de planeamento e projetos de construção de hoje para poder ter esse modo de transporte aéreo emergente disponível no futuro. À medida que a tecnologia subjacente ao eVTOL PATS evolui, é provável que a adoção mais ampla do eVTOL em vários mercados seja ainda mais apoiada se um conjunto de desafios importantes, como segurança e proteção, facilidade de uso e autonomia, ruído, infraestrutura e gestão de tráfego aéreo forem superados. Alcançar melhorias drásticas na facilidade de uso, segurança e ruído aceitável pela comunidade são os passos mais críticos para a viabilidade futura deste mercado. Demonstrações multi-uso e demonstração de operação bem- sucedida com veículos iniciais, ou seja, operações de campo do protótipo eVTOL PATS, criarão aceitação pública e compreensão dos potenciais no modo de transporte aéreo emergente para o bem público, uso e aprendizado em várias aplicações. A percepção geral do utilizador, prestador de serviço e regulador é positiva, e o suporte é alto. Uma implementação bem-sucedida e uma transição sustentável dependerá da superação de obstáculos tecnológicos, estruturas regulatórias, segurança operacional, competitividade de custos e sensibilidade das comunidades afetadas. Há uma necessidade de permitir que pessoas e mercadorias tenham a conveniência de viagens seguras de que necessitam, ponto a ponto, e além disso, em qualquer lugar em menos tempo de viagem. Isso pode ser feito por meio de uma rede de aeroportos/vertiports, e há um benefício potencial significativo para que os formuladores de políticas, reguladores e departamentos de planeamento de transporte das grandes metrópoles considerem a inclusão do modo de transporte aéreo eVTOL nos cenários e políticas do futuro