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Traffic shockwaves are a regularly occurring phe-nomenon in traffic that are a source of irritation and delaysfor the road users. One type of shockwave is the stop-and-gowave which forces entering drivers to stop and advance slowlyuntil the wave is passed. This project aims to design a controlalgorithm through the use of models and simulations to increasethe rate at which a stop-and-go wave dissipates. To design themodel and algorithm the Simulation of Urban MObility (SUMO)simulator and the Traffic Control Interface (TraCI) were usedin conjunction with Python. The setup used for simulation wasthat of a one way, two lane highway with an artificially inducedstop-and-go wave.The designed algorithm manages to dissipate a stop-and-go wavecompletely without introducing new ones. / Trafikvågorär ett vanligt förekommandefenomen i trafiken vilketär en orsak till frustration ochförseningar. En typ av vågär startochstop vågen som tvingarförare att stanna och långsamt fortsätta genom vågen tills denpasserat. Målet med detta projektär att utveckla en kontrol-lalgoritm med hjälp av modeller och simuleringar för attökaavtagandet av en sådan våg. För att utveckla modellen ochalgoritmen används simulatorn Simulation of Urban MObility(SUMO) och Traffic Control Interface (TraCI) i kombinationmed programmeringsspråket Python. Simulering gjordes på ettnätverk bestående av en enkelriktad, tvåfilig motorväg med enkonstgjord startochstop våg.En algoritm utvecklades som kan skingra en startochstop vågutan att skapa nya. / Kandidatexjobb i elektroteknik 2020, KTH, Stockholm

With an increasing population of super heavy aircraft operating in the National Airspace System and with the introduction of NextGen technologies, the wake vortex problem has become more important for airport capacity and the en-route air traffic operations. The vortices generated by heavy and super heavy aircraft can generate potential hazards to other aircraft on nearby flight paths. Moreover, the design of new airport procedures needs to consider the interactions between aircraft in closer paths. New methods and models are required to examine these effects before new operations are conducted in the National Airspace System (NAS). Reducing wake vortex separations to safe levels between successive aircraft is essential for NextGen operations. One approach taken recently by ICAO and the FAA is to introduce a re-categorization (ReCat) of wake vortex separations to six groups from the existing five groups employed by the FAA in the United States. Reduced aircraft separations can increase capacity in the NAS with corresponding savings in delay times at busy airports. Future NextGen operations are likely to introduce smaller aircraft separations in the en-route and in the terminal area. Such operations would require better methods to identify potential wake hazards from reduced separation operations. This dissertation describes a model to identify potential wake encounters in the future NAS. The goal of the dissertation is to describe the Enhanced Wake Encounter Model (EWEM), a model that employs a detailed NASA-developed wake model to generate wake zones for different aircraft categories under different flight conditions that can be used with aircraft flight path data to identify potential wake encounters. The main contribution of this model is to gain an understanding of potential wake encounters under future NAS operations. / Ph. D.

No / Selection of the most appropriate traffic control actions to solve non-recurrent traffic congestion is a complex task, which requires significant expert knowledge and experience. Also, the application of a control action for solving a local traffic problem could create traffic congestion at different locations in the network because of the strong interrelations between traffic situations at different locations of a road network. Therefore, coordination of control strategies is required to make sure that all available control actions serve the same objective. In this paper, an Intelligent Traffic Control System (ITCS) based on a coordinated-agent approach is proposed to assist the human operator of a road traffic control centre to manage the current traffic state. In the proposed system, the network is divided into sub-networks, each of which has its own associated agent. The agent of the sub-network with an incident reacts with other affected agents in order to select the optimal traffic control action, so that a globally acceptable solution is found. The agent uses an effective way of calculating the control action fitness locally and globally. The capability of the proposed ITCS has been tested for a case study of a part of the traffic network in the Riyadh city of Saudi Arabia. The obtained results show its ability to identify the optimal global control action. (C) 2012 Elsevier B.V. All rights reserved.

The aim of this study was to investigate how air traffic controllers cope with stress and also to determine whether there were statistically significant differences in the coping behaviour of air traffic control staff from different groups. The study was conducted on a sample of Air Traffic Controllers who control civilian aircraft in the South African airspace. The coping resources inventory (CRI) assessment was used to collect data and analysed to determine how controllers cope with stress and whether there are differences in the coping behaviour of air traffic control staff from different groups. The results showed that air traffic controllers use emotional coping resources to cope with stressful work situations and make less use of cognitive coping resources. The results also showed that there were no statistically significant differences in the coping behaviour of air traffic control staff from different groups. / Industrial and organisational psychology / M.A. (Industrial and Organisational Psychology)

M. Tech. (Information Technology, Faculty of Applied and Computer Sciences), Vaal University of Technology / Traffic congestion is a concern within the main arteries that link Johannesburg to Pretoria. In this study Matlab function Randperm is used to generate random vehicle speeds on a simulated highway. Randperm is used to mimic vehicle speed sensors capturing vehicle traffic on the highway. Java sockets are used to send vehicle speed to the Road Traffic Control Centre (RTCC)-database server through a wireless medium. The RTCC-database server uses MySQL to store vehicle speed data. The domain controller with active directory together with a certificate server is used to manage and provide security access control to network resources. The wireless link used by speed sensors to transmit vehicle speed data is protected using PEAP with EAP-TLS which employs the use of digital certificates during authentication. A java database connectivity driver is used to retrieve data from MySQL and a multilayer perceptron (MLP) model is used to predict future traffic status on the highway being monitored i.e. next 5 minutes from previous 5 minutes captured data. A dataset of 402 instances was divided as follows: 66 percent training data was used to train the MLP model, 15 percent data used during validation and the remaining 19 percent was used to test the trained MLP model. An excel spreadsheet was used to introduce novel (19 percent data not used during training) data to the trained MLP model to predict. Assuming that the spreadsheet data represent captured highway vehicle data for the last 5 minutes, the model showed 100 percent accuracy in predicting the four classes: congested, out congested, into congested and normal traffic flow. Predicted traffic status is displayed for the motorist on the highway to know. Ability of the proposed model to continuously capture the traffic pattern on the highway (monitor) helps in redirecting (controlling) the highway traffic during periods of congestion. Implementation of this project will definitely decrease traffic congestion across main arteries of Johannesburg. Pollution normally experienced when cars idle for a long time during congestion will be reduced by free highway traffic flow. Frequent servicing of motor vehicles will no longer be required by the motorists. Furthermore the economy of Gauteng and South Africa as a whole will benefit due to increase in production. Consumers will also benefit in obtaining competitive prices from organizations that depend on haulage services.

Cette thèse s’inscrit dans le domaine de la programmation mathématique appliquée à la séparation d’aéronefs stabilisés en altitude. L’objectif est le développement d’algorithmes de résolution de conflits aériens ; l’enjeu étant d’augmenter la capacité de l’espace aérien afin de diminuer les retards et d’autoriser un plus grand nombre d’aéronefs à suivre leur trajectoire optimale. En outre, du fait de l’imprécision des prédictions relatives à la météo ou à l’état des aéronefs, l’incertitude sur les données est une caractéristique importante du problème. La démarche suivie dans ce mémoire s’attache d’abord au problème déterministe dont l’étude est nettement plus simple. Pour cela, quatre modèles basés sur la programmation non linéaire et sur la programmation linéaire à variables mixtes sont développés en intégrant notamment un critère reflétant la consommation de carburant et la durée de vol. Leur comparaison sur un ensemble de scénarios de test met en évidence l’intérêt d’utiliser un modèle linéaire approché pour l’étude du problème avec incertitudes. Un champ de vent aléatoire, corrélé en temps et en espace, ainsi qu’une erreur gaussienne sur la mesure de la vitesse sont ensuite pris en compte.Dans un premier temps, le problème déterministe est adapté en ajoutant une marge sur la norme de séparation grâce au calcul d’une approximation des probabilités de conflits. Finalement, une formulation stochastique avec recours est développée. Ainsi, les erreurs aléatoires sont explicitement incluses dans le modèle afin de tenir compte de la possibilité d’ordonner des manoeuvres de recours lorsque les erreurs observées engendrent de nouveaux conflits. / This thesis belongs to the field of mathematical programming, applied to the separation of aircraft stabilised on the same altitude. The primary objective is to develop algorithms for the resolution of air conflicts. The expected benefit of such algorithm is to increase the capacity of the airspace in order to reduce the number of late flights and let more aircraft follow their optimal trajectory. Moreover, meteorological forecast and trajectory predictions being inexact,the uncertainty on the data is an important issue. The approach that is followed focuses on the deterministic problem in the first place because it is much simpler. To do this, four nonlinear and mixed integer linear programming models, including a criterion based on fuel consumption and flight duration, are developed. Their comparison on a benchmark of scenarios shows the relevance of using an approximate linear model for the study of the problem with uncertainties.A random wind field, correlated in space and time, as well as speed measures with Gaussianerrors are then taken into account. As a first step, the deterministic problem is adapted by computinga margin from an approximate calculation of conflict probabilities and by adding it tothe reference separation distance. Finally, a stochastic formulation with recourse is developed.In this model, the random errors are explicitly included in order to consider the possibility of ordering recourse actions if the observed errors cause new conflicts.

O transporte aéreo e a indústria de sistemas de defesa foram setores pioneiros na utilização de sistemas computacionais críticos, incrementando os níveis de automação nas atividades de controle do espaço aéreo. Com o crescimento desses setores, verificado pela expansão dos números de vôos, volumes de cargas e usuários, assim como pela ampliação e diversidade das operações militares, os sistemas de controle têm assumido maior complexidade técnica, introduzindo novos recursos de automação ou facilidades adicionais de apoio para funções exercidas manualmente. Essa situação tem ampliado a dependência dos serviços prestados, relativamente à disponibilidade dos sistemas computacionais. Diretrizes de projeto e procedimentos operacionais são estabelecidos para manter os níveis de segurança nos casos de falha, no entanto a disponibilidade torna-se parâmetro crítico, na medida em que algumas falhas podem afetar a eficiência nominal da prestação dos serviços. Nesse cenário, este trabalho propõe um modelo para avaliação da disponibilidade de sistemas de controle do espaço aéreo, a partir de recursos de análises da teoria de filas. Inicialmente é citado um modelo geral para análise de disponibilidade de data centers. Em seguida, é apresentada uma extensão do modelo geral para análise da disponibilidade em sistemas de controle do espaço aéreo. Para isso, considerou-se a intervenção humana existente nessa atividade, cujas decisões de controle são exercidas por operadores qualificados (controladores), tanto nas atividades inerentes ao serviço de controle, quanto nos casos de degradação, nos quais os operadores ou técnicos de manutenção assumem alguma tarefa de reparo, decorrente da eventual indisponibilidade de funções do sistema. / Due to the growth in airspace utilization, which can be verified both in terms of the expansions in aerial movements, airports and volumes of transported passengers and cargo, as well as in terms of the expansion of military operations demands and diversity, airspace control activities have been increasing their technical complexity, introducing new features into the existent automation systems or creating additional resources for the automation of some functions previously performed by human operators. This situation has increased the dependence on the availability of the computer systems involved in the services provided by control centers. Project directives and operational procedures are established in order to maintain the safety integrity levels of the systems, in case any failure occurs. However, the availability becomes a critical parameter, once failure events can force an undesirable state of degraded operation, jeopardizing the nominal capacity of the services being performed through any controlled airspace. In this scenario, this work presents an availability model for the computer systems used in airspace control centers, based on analysis from queuing theory. A general model is first presented, referencing a case study that describes the use of queuing models to access the availability of generic data centers. Further considerations are introduced to extend this general model in order to propose its application for the specific computer systems used in airspace control centers, where operational control relies on human activities. In this case, system operation involves intensive use of human-machine interfaces (HMI), for the regular control services provided, and additional technical or operational maintenance activities, occasionally imposed to repair a momentary loss of any function of the system.

Com o crescimento do setor aeronáutico faz-se necessário a criação de novas tecnologias para que a capacidade do sistema possa aumentar sem provocar perdas nos níveis de segurança. Para isso foi criado o CNS/ATM, um paradigma que integra tecnologias de comunicação, navegação e vigilância em um sistema de gerenciamento de tráfego aéreo global. No âmbito das comunicações entre controlador e piloto, o atual sistema de fonia via rádio analógico é substituído por um enlace de dados, chamado de Controller-Pilot Data Link Communication (CPDLC). Esta alteração promove polêmica entre aeronautas e autoridades, de forma que é essencial um estudo aprofundado que comprove sua eficácia. Dessa forma, esta pesquisa visa avaliar a segurança do CPDLC quando utilizado em Áreas Terminais do Espaço Aéreo. Para a realização desta pesquisa, foi criada uma metodologia de avaliação de segurança utilizando simuladores de voo, de tráfego aéreo e de comunicação CPDLC combinados com uma análise por meio de modelos de Markov. O procedimento de chegada ao aeroporto de Congonhas, situado na Terminal São Paulo, foi utilizado como referência para aplicação desta metodologia. Os resultados obtidos mostraram que o sistema atual de comunicação, via voz, está no limite do atendimento dos níveis internacionais de segurança para a demanda atual. Contudo, a comunicação por enlace de dados atende, e em alguns casos inclusive melhora, o nível de segurança desta região do espaço aéreo. / With the growth of the aviation industry it is necessary to create new technologies that can increase the system capacity without loss in the safety levels. Because of this the CNS/ATM was created, a paradigm that integrates communication, navigation and surveillance technologies with a global air traffic management. For the communications between controllers and pilots, the current system of voice over analog radio is being replaced by a data link, called the Controller-Pilot Data Link Communication (CPDLC). This replacement raises debates between airmen and authorities, demanding a detailed study that proves its effectiveness. Thus, this research aims to evaluate the CPDLC safety when used in Terminal Airspace Areas. For this research, was created a methodology for security assessment using flight, air traffic, and CPDLC simulators combined with a Markov model analysis. The Congonhas airport arrival procedure, located in São Paulo Terminal, was used as reference for this methodology application. The results showed that the current system of voice communication is on the limit of fulfilling the international safety levels for the current demand. However, the data link communication addresses, and in some cases even improve, the safety level for this airspace region.