User Feedback-Informed Interface Design for Flow Management Data and Services (FMDS)

The transition to a microservices-based Flow Management Data and Services (FMDS) architecture from the existing Traffic Flow Management System (TFMS) is a critical enabler of the vision for an Information-Centric National Airspace System (NAS). The need to design a user-centric interface for FMDS is a key technical gap, as this interface connects NAS data and services to the traffic management specialists within all stakeholder groups (e.g., FAA, airlines). We provide a research-driven approach towards designing such a graphical user interface (GUI) for FMDS. Major goals include unifying the more than 50 disparate traffic management services currently hosted on TFMS, as well as streamlining the process of evaluating, modeling, and monitoring Traffic Management Initiatives (TMIs). Motivated by this, we iteratively designed a GUI leveraging human factors engineering and user experience design principles, as well as user interviews. Through user testing and interviews, we identify workflow benefits of our GUI (e.g., reduction in task completion time), along with next steps for developing a live prototype.Comment: 8 pages, 8 figure

Allocating Air Traffic Flow Management Slots

In Europe, when an imbalance between demand and capacity is detected for air traffic network resources, Air Traffic Flow Management slots are allocated to flights on the basis of a First Planned First Served principle. We propose a market mechanism to allocate such slots in the case of a single constrained en-route sector or airport. We show that our mechanism provides a slot allocation which is economically preferable to the current one as it enables airlines to pay for delay reduction or receive compensations for delay increases. We also discuss the implementation of our mechanism through two alternative distributed approaches that spare airlines the disclosure of private information. Both these approaches have the additional advantage that they directly involve airlines in the decision making process. Two computational examples relying on real data illustrate our findings.Air Transportation, Market Mechanism Design, Air Traffic Flow Management slots, Collaborative Decision Making, SESAR.

Evaluating air traffic flow management in a collaborative decision-making environment

The collaborative decision-making (CDM) framework introduced into ground delay programs in the late 1990s is an integral component of FAA's traffic flow management (TFM) procedures. CDM allows FAA to act as a mediator when managing TFM programs, transferring as much decision making as possible to the individual airlines. Although this approach has been highly successful in practice, it creates a new question for the research community: How should proposed enhancements to TFM be evaluated in a CDM environment? A sequential evaluation procedure, developed in this paper, addresses this question. The procedure includes airline disruption responses and a quasi-compression operation, attempting to mimic the three-stage CDM process. To model airline disruption responses, an integer optimization model was developed to balance operational and passenger considerations in determining which flights to cancel, swap, or delay. The value of this procedure is demonstrated by analyzing an optimization-based TFM approach in the CDM environment

MODELS AND SOLUTION ALGORITHMS FOR EQUITABLE RESOURCE ALLOCATION IN AIR TRAFFIC FLOW MANAGEMENT

Population growth and economic development lead to increasing demand for travel and pose mobility challenges on capacity-limited air traffic networks. The U.S. National Airspace System (NAS) has been operated near the capacity, and air traffic congestion is expected to remain as a top concern for the related system operators, passengers and airlines. This dissertation develops a number of model reformulations and efficient solution algorithms to address resource allocation problems in air traffic flow management, while explicitly accounting for equitable objectives in order to encourage further collaborations by different stakeholders. This dissertation first develops a bi-criteria optimization model to offload excess demand from different competing airlines in the congested airspace when the predicted traffic demand is higher than available capacity. Computationally efficient network flow models with side constraints are developed and extensively tested using datasets obtained from the Enhanced Traffic Management System (ETMS) database (now known as the Traffic Flow Management System). Representative Pareto-optimal tradeoff frontiers are consequently generated to allow decision-makers to identify best-compromising solutions based on relative weights and systematical considerations of both efficiency and equity. This dissertation further models and solves an integrated flight re-routing problem on an airspace network. Given a network of airspace sectors with a set of waypoint entries and a set of flights belonging to different air carriers, the optimization model aims to minimize the total flight travel time subject to a set of flight routing equity, operational and safety requirements. A time-dependent network flow programming formulation is proposed with stochastic sector capacities and rerouting equity for each air carrier as side constraints. A Lagrangian relaxation based method is used to dualize these constraints and decompose the original complex problem into a sequence of single flight rerouting/scheduling problems. Finally, within a multi-objective utility maximization framework, the dissertation proposes several practically useful heuristic algorithms for the long-term airport slot assignment problem. Alternative models are constructed to decompose the complex model into a series of hourly assignment sub-problems. A new paired assignment heuristic algorithm is developed to adapt the round robin scheduling principle for improving fairness measures across different airlines. Computational results are presented to show the strength of each proposed modeling approach

COMPUTATIONALLY TRACTABLE STOCHASTIC INTEGER PROGRAMMING MODELS FOR AIR TRAFFIC FLOW MANAGEMENT

A primary objective of Air Traffic Flow Management (ATFM) is to ensure the orderly flow of aircraft through airspace, while minimizing the impact of delays and congestion on airspace users. A fundamental challenge of ATFM is the vulnerability of the airspace to changes in weather, which can lower the capacities of different regions of airspace. Considering this uncertainty along with the size of the airspace system, we arrive at a very complex problem. The development of efficient algorithms to solve ATFM problems is an important and active area of research. Responding to predictions of bad weather requires the solution of resource allocation problems that assign a combination of ground delay and route adjustments to many flights. Since there is much uncertainty associated with weather predictions, stochastic models are necessary. We address some of these problems using integer programming (IP). In general, IP models can be difficult to solve. However, if "strong" IP formulations can be found, then problems can be solved quickly by state of the art IP solvers. We start by describing a multi-period stochastic integer program for the single airport stochastic dynamic ground holding problem. We then show that the linear programming relaxation yields integer optimal solutions. This is a fairly unusual property for IP formulations that can significantly reduce the complexity of the corresponding problems. The proof is achieved by defining a new class of matrices with the Monge property and showing that the formulation presented belongs to this class. To further improve computation times, we develop alternative compact formulations. These formulations are extended to show that they can also be used to model different concepts of equity and fairness as well as efficiency. We explore simple rationing methods and other heuristics for these problems both to provide fast solution times, but also because these methods can embody inherent notions of fairness. The initial models address problems that seek to restrict flow into a single airport. These are extended to problems where stochastic weather affects en route traffic. Strong formulations and efficient solutions are obtained for these problems as well

Polarization and opinion analysis in an online argumentation system for collaborative decision support

Argumentation is an important process in a collaborative decision making environment. Argumentation from a large number of stakeholders often produces a large argumentation tree. It is challenging to comprehend such an argumentation tree without intelligent analysis tools. Also, limited decision support is provided for its analysis by the existing argumentation systems. In an argumentation process, stakeholders tend to polarize on their opinions, and form polarization groups. Each group is usually led by a group leader. Polarization groups often overlap and a stakeholder is a member of multiple polarization groups. Identifying polarization groups and quantifying a stakeholder\u27s degree of membership in multiple polarization groups helps the decision maker understand both the social dynamics and the post-decision effects on each group. Frameworks are developed in this dissertation to identify both polarization groups and quantify a stakeholder\u27s degree of membership in multiple polarization groups. These tasks are performed by quantifying opinions of stakeholders using argumentation reduction fuzzy inference system and further clustering opinions based on K-means and Fuzzy c-means algorithms. Assessing the collective opinion of the group on individual arguments is also important. This helps stakeholders understand individual arguments from the collective perspective of the group. A framework is developed to derive the collective assessment score of individual arguments in a tree using the argumentation reduction inference system. Further, these arguments are clustered using argument strength and collective assessment score to identify clusters of arguments with collective support and collective attack. Identifying outlier opinions in an argumentation tree helps in understanding opinions that are further away from the mean group opinion in the opinion space. Outlier opinions may exist from two perspectives in argumentation: individual viewpoint and collective viewpoint of the group. A framework is developed in this dissertation to address this challenge from both perspectives. Evaluation of the methods is also presented and it shows that the proposed methods are effective in identifying polarization groups and outlier opinions. The information produced by these methods help decision makers and stakeholders in making more informed decisions --Abstract, pages iii-iv

Cost-based linear holding practice and collaborative air traffic flow management under trajectory based operations

The current air transportation system is reaching the capacity limit in many countries/regions across the world. It tends to be less efficient or even incapable sometimes to deal with the enormous air traffic demand that continues growing year by year. This has been evidenced by the record-breaking flight delays reported in various places in recent years, which, have resulted in notable economical loses. To mitigate this imbalance between demand and capacity, air traffic flow management (ATFM) is usually one of the most useful options. It regulates traffic flows according to air traffic control capacity while preserving safety and efficiency of flights. ATFM initiatives can be considered well in advance of the flight execution - more than one year earlier - based on air traffic forecasts and capacity plans, and continue in effect, with information updated, to eventually the day of operation. This long effective period will inevitably allow substantial collaboration among different stakeholders, including the ATFM authority, airspace users (AUs), air navigation service providers (ANSPs), airports, etc. Under the forthcoming paradigm of trajectory based operations (TBO), the flight 4-Dimensional trajectory has been anticipated to further enhance the connection between flight planning and execution phases, thus fostering such collaboration in ATFM. Moreover, under nowadays operations, ground holding is a typical measure undertaken in many widely-used ATFM programs. Even though holding on the ground, at the origin airport, has the advantage of fuel efficiency over the air holding, it turns out that its feature of low flexibility would, in some circumstances, affect the ATFM performance. Yet, with proper flight trajectory management, it is also possible to have delay airborne at no extra fuel cost than performing ground holding. This PhD thesis firstly focuses on this trajectory management, specifically on a cost-based linear holding practice. The linear holding is realized progressively along the planned trajectory through precise speed control which can be enabled by aircraft trajectory optimization techniques. Some typical short/mid haul flights are simulated for achieving the maximum airborne delay that can be yielded using same fuel consumption as initially scheduled. Based on this, its potential applicability is demonstrated. A network ATFM model is adapted from the well-studied Bertsimas Stock-Patterson (BSP) model, incorporating different types of delay (including the linear holding) to flexibly handle the traffic flow with a set of given (yet changeable) capacities. In order that the benefits of the model can be fully realized, AUs are required to participate in the decision-making process, submitting for instance the maximum linear holding bound per flight along the planned trajectory. Next, increased AUs' participation is expected for a proposed Collaborative ATFM framework, in which not only various delay initiatives are considered, but also alternative trajectories which allow flights to route out of the identified hotspot areas. A centralized linear programming optimization model then computes for the best trajectory selections and the optimal delay distributions across all concerned flights. Finally, ANSPs' involvement is additionally considered for the framework, through dynamic airspace reconfiguration, further enhancing the collaboration between ATFM stakeholders. As such, the traffic flow regulation and sector opening scheduling are bounded into an integrated optimization model, and thus are conducted in a synchronized way. Results indicate that the performance of demand and capacity balancing can be even improved if compared with the previous ATFM models presented in this PhD thesis.El sistema de transport aeri actual està arribant al seu límit de capacitat en molts països i regions del món. Una gestió del flux de trànsit aeri (ATFM) més adequada podria mitigar aquest desequilibri entre la demanda i la capacitat. La funció de l'ATFM és regular els fluxos de trànsit aeri segons la capacitat de control del trànsit aeri, i alhora assegurar que els vols siguin segurs i eficients. Les regulacions del sistema d'ATFM es poden aplicar molt abans de l'execució del vol més d'un any abans. Un cop aplicades, aquestes regulacions continuaran evolucionant, amb informació actualitzada, fins el dia de la seva execució. El llarg període entre la planificació del vol i la seva execució permetrà una important col·laboració entre els diferents membres implicats, inclosa l'autoritat de l'ATFM, els usuaris de l'espai aeri (AUs), els proveïdors de serveis de navegació aèria (ANSP), els aeroports, etc. En les operacions d'avui en dia l'espera a terra és una de les regulacions que més aplica el sistema d'ATFM per tal d'evitar congestions als aeroports o sectors de l'espai aeri. Tot i que esperar a terra, a l'aeroport d'origen, té l'avantatge de consumir menys combustible que esperar a l'aire a l'aeroport de destí, la seva poca flexibilitat podria afectar negativament al rendiment de l'ATFM en algunes circumstàncies. Tanmateix, amb una gestió adequada de la trajectòria de vol, també és possible efectuar cert retard a l'aire sense cap cost addicional de combustible respecte al que resultaria esperant a terra. Aquesta tesi doctoral s'enfoca en primer lloc en aquesta gestió de trajectòria de vol, específicament en una pràctica d'espera tenint en compte els costos per l'aerolínia. L'espera lineal s'efectua progressivament al llarg de la trajectòria planificada mitjançant un control precís de la velocitat. Les velocitats que generen l'espera desitjada durant el vol és calculen mitjançant tècniques d'optimització. Alguns vols típics de curt i mig abast es simulen per quantificar el màxim retard a l'aire que es podria generar utilitzant el mateix consum de combustible que el previst inicialment. Basant-se en els resultats obtinguts, s'explora la seva aplicabilitat potencial. Es desenvolupa un model de la xarxa d'ATFM basat en el model de Bertsima Stock-Patterson. Com a novetat, el model desenvolupat en aquesta tesi incorpora diferents tipus de retard (incloent-hi l'espera lineal) per gestionar de forma més flexible el flux de trànsit donat un conjunt de capacitats pre-definides. Per tal d'explotar al màxim els beneficis del model proposat en aquesta tesi, les autoritats regionals estan obligades a participar en el procés de presa de decisions, declarant, per exemple, la màxima espera lineal associada a cada vol al llarg de la trajectòria planejada. Tot seguit, s'inclou la participació dels AUs en un sistema d'ATFM col·laboratiu, en el qual no només es consideren diverses tipus de retard per balancejar la capacitat i la demanda, sinó també trajectòries alternatives que permeten que els vols evitin de forma òptima els sectors de l?espai aeri congestionats. Un model d'optimització centralitzat basat en programació lineal calcula les millors seleccions de trajectòria i les distribucions òptimes de retard en tots els vols afectats per la regulació. Es demostra que incloure trajectòries alternatives pot reduir notablement la quantitat de retards. Finalment, es considera també la participació de l'ANSP en el sistema d'ATFM, a través de la configuració dinàmica de l'espai aeri, millorant encara més la col·laboració entre els membres implicats en el sistema. Com a tal, la regulació del flux de trànsit i la programació d'obertura dels diferents sectors de l'espai aeri s'inclouen en un model integrat d'optimització i, per tant, es programen de forma sincronitzada. Els resultats suggereixen que el rendiment del balanc¸ de la demanda i la capacitat es pot millorar encara m´es amb aquest sistema ATFM col·laboratiu complert. El nou model de balanc¸ de demanda i capacitat millora encara ées els resultats, si es compara amb els altres models d’ATFM presentats també en aquesta tesi doctoral.El sistema de transporte aéreo actual está llegando a su límite de capacidad en muchos países y regiones del mundo. Como consecuencia, éste tiende a ser menos eficiente e incluso en ocasiones incapaz de afrontar la enorme demanda de tráfico aéreo que incluso hoy en día crece rápidamente. Este hecho se ha visto evidenciado por los enormes retrasos registrados en diferentes lugares los últimos años, lo cual ha comportado enormes pérdidas económicas para la sociedad. Una gestión del flujo del tráfico aéreo (ATFM) más adecuada podría mitigar este desequilibrio entre la demanda y la capacidad. La función del ATFM es regular los flujos de tráfico aéreo según la capacidad de control del tráfico aéreo, siempre asegurando que los vuelos sean seguros y eficientes. Las regulaciones del sistema de ATFM se pueden aplicar mucho antes de la ejecución del vuelo –más de un año antes– en función de las previsiones de tráfico aéreo y de la capacidad esperada. Una vez aplicadas, estas regulaciones continuarán evolucionando, con información actualizada, hasta el día de su ejecución. El largo periodo entre la planificación del vuelo y su ejecución permitirá una importante colaboración entre los diferentes miembros implicados, incluida la autoridad del ATFM, los usuarios del espacio aéreo (AUs), los proveedores de servicios de navegación aérea (ANSP), los aeropuertos, etc. En el marco del futuro paradigma de las operaciones basadas en trayectorias, la introducción de vuelos con control sobre la trayectoria en las 4 dimensiones espera mejorar aún más la conexión entre las fases de planificación del vuelo y su ejecución, fomentando así la colaboración en el proceso de toma de decisiones del sistema ATFM. En las operaciones de hoy en día la espera en tierra es una de las regulaciones que más se aplica en el sistema de ATFM con el fin de evitar congestiones en los aeropuertos o en los sectores del espacio aéreo. Aun teniendo en cuenta que esperar en tierra, en el aeropuerto de origen, tiene la ventaja de consumir menos combustible que esperar en el aire en el aeropuerto de destino, su poca flexibilidad podría afectar negativamente al rendimiento del ATFM en algunas circunstancias. Aun así, con una gestión adecuada de la trayectoria de vuelo, también es posible efectuar cierto retraso en el aire sin ningún coste adicional de combustible respecto a lo que resultaría esperando en tierra. Esta tesis doctoral se centra en primer lugar en esta gestión de la trayectoria de vuelo, específicamente en una práctica de espera lineal considerando los costes para la aerolínea. La espera lineal se efectúa progresivamente a lo largo de la trayectoria planificada mediante un control preciso de la velocidad. Las velocidades que generan la espera deseada durante el vuelo se calculan mediante técnicas de optimización. Algunos vuelos típicos de corto y medio alcance se simulan para cuantificar el máximo retraso en el aire que se podría generar utilizando el mismo consumo de combustible que el previsto inicialmente. Basándose en los resultados obtenidos, se investiga su potencial aplicabilidad, como por ejemplo mejorar la planificación de programas de flujo del espacio aéreo, y ayudar a neutralizar los retrasos no deseados adicionales debidos a la incertidumbre del sistema. Se desarrolla un modelo de la red de ATFM basado en el conocido modelo Bertsimas Stock-Patterson (BSP). Como novedad, el modelo desarrollado en esta tesis incorpora diferentes tipos de retraso (incluyendo la espera lineal) para gestionar de manera más flexible el flujo de tráfico dado un conjunto de capacidades predefinidas. Con el fin de explotar al máximo los beneficios del modelo propuesto en esta tesis, se asume que las aerolíneas participaran en el proceso de toma de decisiones, declarando, por ejemplo, la máxima espera lineal asociada a cada vuelo a lo largo de la trayectoria planeada. Este concepto se ilustra con un caso de estudio, donde se demuestra una reducción significativa de los retrasos, comparado con el modelo BSP. Seguidamente, se incluye la participación de las aerolíneas en un sistema de ATFM colaborativo, en el cual no tan sólo se consideran diferentes tipos de retrasos para balancear la capacidad y la demanda, sino también trayectorias alternativas que permiten que los vuelos eviten de forma óptima los sectores del espacio aéreo congestionados. Un modelo de optimización centralizado basado en programación lineal calcula las mejores selecciones de la trayectoria y las distribuciones óptimas de retraso en todos los vuelos afectado por la regulación. Se demuestra que incluir trayectorias alternativas puede reducir notablemente la cantidad de retrasos. Finalmente, se considera también la participación de los ANSP en el sistema de ATFM, a través de la configuración dinámica del espacio aéreo, mejorando aún más la colaboración entre los miembros implicados en el sistema. Como tales, la regulación del flujo de tráfico aéreo y la programación de apertura de los diferentes sectores del espacio aéreo se incluyen en un modelo integrado de optimización y, por lo tanto, se programan de manera sincronizada. El nuevo modelo de balance de demanda y capacidad mejora aún más los resultados, si se compara con los otros modelos ATFM presentados también en esta tesis doctoralPostprint (published version

Examination of air transportation trip time variability

Scheduled air transportation is required to provide a service that is safe, consistent, and dependable, with reliable trip times and delays managed within acceptable limits. High trip time variability and delay in the current system are driven by multiple factors; The study objectives were: (1) to develop a comprehensive database for individual major U.S. airline domestic trips between 1995 and 2005; (2) to explore the central tendency and variability of airline gate-to-gate trip times and delays; (3) to develop values for unconstrained, or unimpeded, trip times, and (4) to develop traveler and airline delay and variability costs relative to unimpeded trip times; The research used U.S. Department of Transportation (U.S. DOT) data for scheduled domestic airline trips reported by major U.S. air carriers between 1995 and 2005. For valuing air carrier cost savings, this research estimated variable costs for individual trips, based on individual carrier financial reports to U.S. DOT; The research used reported trip times as a primary indicator, unimpeded trip times as a reference, and attached a cost to the excess of reported trip time over unimpeded trip time at the individual flight level. This approach represents a process for evaluating the time savings and operating cost impacts of measures for increasing capacity and reducing impedance in U.S. domestic scheduled air transportation; Areas in which trip time variability and delay impose a high penalty on travelers and airlines were identified. The most important study results concerned disproportionately higher delays and costs relative to: (1) origin and destination airports and corridors; (2) times of day; and (3) the days with highest delays. The main areas were arrivals and departures at leading airports (40 percent of flights and 55 percent of costs), flight departures and arrivals between noon and early evening (50 percent of flights and 60 percent of costs), and during the 40 percent of days in which there were heavy system wide delays (55 percent of costs) costs appropriate to time changes on individual trips, the magnitude of penalties incurred by impeded trips were estimated relative to unimpeded trips. These were: 150 million annual excess traveler hours per year; {dollar}8 billion annual excess air carrier operating costs; with 400 million annual gallons of excess jet fuel consumption. The costs of impeded trips added about 10 percent (or about {dollar}3.4 billion annually) to airline variable operating costs during the study period

Runway operations scheduling using airline preferences

Koole, G.M. [Promotor