The Multiple Remote Tower Center concept (mRTC) is a cutting edge project which allows one air traffic control officer (ATCO) to be in charge of multiple remotely situated airports simultaneously. When implemented, it will revolutionise how air traffic is managed at smaller airports and allow for increased efficiency and decreased operational costs. Consequently, at the time of writing a lot of effort is going into evaluating this new way of air traffic management from a safety perspective. Air traffic management has been defined as an issue maintaining situational awareness and exercising control. This thesis aims to investigate how the phenomenon target fascination affects the ATCOs ability to exercise control over its controlled airspace and maintain its situation awareness. It does so by creating a baseline scenario of work in a mRTC, and then comparing the ATCOs performance in the baseline scenario with its performance in the same corresponding scenario, but with elements of target fascination introduced. The differences in the scenarios are analysed using the Contextual Control Model, the Extended Control Model and a holistic framework for studying situation awareness. The analysis shows that target fascination does affect the ATCOs ability to maintain control, but not radically so, and only for a short period of time. The target fascination forces the ATCO to rely on information in the immediate environment to a higher degree than during regular work, as opposed to making decisions based on a holistic understanding of the situation and high level goals. However, once the understanding of the situation have been re-established, the level of control quickly returns to normal levels. Situation awareness is thus a key concept in maintaining control. The situation awareness analysis show that target fascination affects situation awareness by causing the ATCOs understanding of the situation to become outdated without the ATCOs knowledge. Because of this, there may be developments in the situation that the ATCO is not aware of, which hinders it from acting as it normally would. In some cases an intervention from an external actor or element may be necessary to break the fascination and re-establish the ATCOs understanding for the situation. As soon as the fascination is broken, the ATCO quickly takes steps to re-establish its situation awareness and return to normal operations.

Transportation agencies are introducing new strategies and techniques that will improve traffic incident management. Apart from other indicators, agencies measure the performance of the strategies by evaluating the incidents timeline. An effective strategy has to reduce the length of the incident timeline. An incident timeline comprises various stages in the incident management procedure, starting when the incident was detected, and ending when there is the recovery of normal traffic conditions. This thesis addresses three issues that are related to the traffic incident timeline and the incident management strategies. First, co-location of responding agencies has not been investigated as other incident management measures. Co-location of incident responders affects the incident timeline, but there is a scarcity of literature on the magnitude of the effects. Evaluation of the co-location strategy is reflected by the response and verification durations because its effectiveness relies on improving communication between agencies. Investigation of the response and verification duration of incidents, before and after operations of a co-located Traffic Management Center (TMC) is done by using hazard-based models. Results indicate that the incident type, percentage of the lane closure, number of responders, incident severity, detection methods, and day-of-the-week influence the verification duration for both the before- and after- period. Similarly, incident type, lane closure, number of responders, incident severity, time-of-the-day, and detection method influence the response duration for both study periods. The before and after comparison shows significant improvements in the response duration due to co-location of incident response agencies. Second, the incident clearance duration may not necessarily reflect how different types of incidents and various factors affect traffic conditions. The duration at which the incident influences traffic conditions could vary – shorter than the incident duration for some incidents and longer for others. This study introduces a performance measure called incident impact duration and demonstrates a method that was used for estimating it. Also, this study investigated the effects of using incident impact duration compared to the traditionally incident clearance duration in incident modeling. Using hazard-based models, the study analyzed factors that affect the estimated incident impact duration and the incident clearance duration. Results indicate that incident detection methods, the number of responders, Traffic Management Center (TMC) operations, traffic conditions, towing and emergency services influence the duration of an incident. Third, elements of the incident timeline before the clearance duration have been overlooked as factors that influence the clearance duration. Incident elements before the clearance duration include verification time, dispatch duration, and the travel time of responders to the incident scene. This study investigated the influence of incident timeline elements before clearance on the extent of the clearance duration. Also, this study analyzed the impact of other spatial and temporal attributes on the clearance duration. The analysis used a Cox regression model that is estimated using the Least Absolute Shrinkage and Selection Operator (LASSO) penalization method. LASSO enables variable selection from incidents data with a high number of covariates by automatically and simultaneously selecting variables and estimating the coefficients. Results suggest that verification duration, response travel duration, the percentage of lane closure, incident type, the severity of an incident, detection method, and crash location influence the clearance duration.

Floating Car Data (FCD) besitzen eine sehr breite Palette an Anwendungsmöglichkeiten, die aber teilweise noch keine massenhafte Verbreitung gefunden haben, auch wenn das Innovationspotenzial als sehr hoch eingeschätzt wird. Dies begründet sich in erster Linie durch die meist relativ großen Erfassungsintervalle bei der derzeitigen FCD-Erfassung. In Dresden ist ein Taxi-FCD-System in Betrieb, welches sich durch eine sehr hohe Detektionsdichte auszeichnet. Die Fahrzeugpositionen werden mindestens alle 5 Sekunden aufgezeichnet. Damit bestehen ausgezeichnete Möglichkeiten, mögliche Mehrwerte zu prüfen und Prototypen zu etablieren. Getestet wurde u. a. die Generierung von Straßennetzabbildern. Im Dauerbetrieb befindet sich die FCD-basierte Verkehrslageermittlung.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The traffic problems are of general scope in several cities in the world, especially in central area, usually more congested. This work aims to simulate an operational alternative that provides improved flow of vehicles in the central area. It is proposed the elimination of parking lots regulated rotary (called Blue Zone ) on the streets and main avenues in the downtown area and meeting this need with the implementation of parking garages/lots in buildings and / or underground garages in places near the central area. Identify the best location for such a development strategy includes facility location approach to logistics and optimization of the distance pathway. It can be pointed out urban politics for Land Use and Transportation, urban planning and needs applied to determine strategic locations for new enterprises considering the logistics. Some strategies of traffic management adopted in Brazil, United States and Europe are generally discussed with their benefits and limitations. The strategic locations were selected considering Clustering and Facility Location approaches using software TransCAD. Reduction of blue zones allows increasing the capacity of lane and therefore, improving the performance in central area. This benefit can be measured through the simulation, using Traffic Software Integrated System, taking into account Traffic Engineering. That is the case of downtown in Uberlandia. Comparing the proposed and real scenario it could be reduced delay and waiting time, fuel consumption and greenhouse gas emissions. The results pointed the better scenario of the central area and also showed it is important to review the land use/transportation. It is necessary to adopt integrated politics to improve the performance of the routes due the increased flow vehicles and traffic problems. The relocation of parking lots is a current alternative which improves the vehicles flow and the mobility in downtown. / Os problemas no trânsito são de amplitude geral em diversas cidades mundiais, principalmente na área central, normalmente, mais congestionada. Este trabalho pretende simular uma alternativa operacional que proporcione melhoria do fluxo de veículos na área central. Para isso, propõe-se a retirada dos estacionamentos regulamentados rotativos (Zona Azul) nas ruas e avenidas principais da área de estudo e o atendimento desta necessidade com a implantação de bolsões de estacionamentos em edifícios garagens e/ou garagens subterrâneas em locais próximos a área central. Identificar o melhor local para um empreendimento desta natureza engloba estratégias de localização de instalações com abordagem em logística e de otimização da distância de caminhamento. Destaca-se a importância das políticas urbanas, como o planejamento urbano e a legislação de uso e ocupação do solo. Algumas estratégias de gerenciamento de tráfego adotadas no Brasil, Estados Unidos e países da Europa são abordados juntamente com seus benefícios e limitações. Os locais estratégicos para estacionamento foram selecionados com base nos procedimentos de Clustering e Facility Location do software TransCAD. Com a retirada das vagas dos estacionamentos rotativos ao longo do meio-fio, obtém-se um aumento na capacidade das vias, devido ao maior número de faixas de tráfego e, portanto, melhor desempenho operacional nas vias da área central. Este benefício é mensurado com abordagem em técnicas de engenharia de tráfego através da simulação no Traffic Software Integrated System (TSIS), adotando o caso típico da área central da cidade de Uberlândia. Analisando-se os dois cenários (cenário real e cenário proposto), percebeu-se uma redução do tempo de espera e atraso, aumento da velocidade média, redução do consumo de combustível dos veículos e das emissões de gases poluentes (HC, CO e NO). Os resultados indicaram melhoria do fluxo de veículos e maior aproveitamento do espaço viário na área central. Este trabalho mostrou ainda, que é importante rever a legislação de uso e ocupação do solo, adotando políticas integradas de transporte para melhorar as condições operacionais das vias. A realocação dos estacionamentos é uma alternativa eficaz e imediata, que melhora o fluxo de veículos e a mobilidade na região central da cidade, deslocando a demanda por vagas para locais isolados fora da área densa. / Mestre em Engenharia Civil

La thèse porte sur la conception et l'analyse mathématique de méthodes de Monte Carlo fiables et précises pour l'estimation de la (très petite) probabilité qu'un processus de Markov atteigne une région critique de l'espace d'état avant un instant final déterministe. L'idée sous-jacente aux méthodes de branchement multi-niveaux étudiées ici est de mettre en place une suite emboitée de régions intermédiaires de plus en plus critiques, de telle sorte qu'atteindre une région intermédiaire donnée sachant que la région intermédiaire précédente a déjà été atteinte, n'est pas si rare. En pratique, les trajectoires sont propagées, sélectionnées et répliquées dès que la région intermédiaire suivante est atteinte, et il est facile d'estimer avec précision la probabilité de transition entre deux régions intermédiaires successives. Le biais dû à la discrétisation temporelle des trajectoires du processus de Markov est corrigé en utilisant des régions intermédiaires perturbées, comme proposé par Gobet et Menozzi. Une version adaptative consiste à définir automatiquement les régions intermédiaires, à l’aide de quantiles empiriques. Néanmoins, une fois que le seuil a été fixé, il est souvent difficile voire impossible de se rappeler où (dans quel état) et quand (à quel instant) les trajectoires ont dépassé ce seuil pour la première fois, le cas échéant. La contribution de la thèse consiste à utiliser une première population de trajectoires pilotes pour définir le prochain seuil, à utiliser une deuxième population de trajectoires pour estimer la probabilité de dépassement du seuil ainsi fixé, et à itérer ces deux étapes (définition du prochain seuil, et évaluation de la probabilité de transition) jusqu'à ce que la région critique soit finalement atteinte. La convergence de cet algorithme adaptatif à deux étapes est analysée dans le cadre asymptotique d'un grand nombre de trajectoires. Idéalement, les régions intermédiaires doivent êtres définies en terme des variables spatiale et temporelle conjointement (par exemple, comme l'ensemble des états et des temps pour lesquels une fonction scalaire de l’état dépasse un niveau intermédiaire dépendant du temps). Le point de vue alternatif proposé dans la thèse est de conserver des régions intermédiaires simples, définies en terme de la variable spatiale seulement, et de faire en sorte que les trajectoires qui dépassent un seuil précocement sont davantage répliquées que les trajectoires qui dépassent ce même seuil plus tardivement. L'algorithme résultant combine les points de vue de l'échantillonnage pondéré et du branchement multi-niveaux. Sa performance est évaluée dans le cadre asymptotique d'un grand nombre de trajectoires, et en particulier un théorème central limite est obtenu pour l'erreur d'approximation relative. / The thesis deals with the design and mathematical analysis of reliable and accurate Monte Carlo methods in order to estimate the (very small) probability that a Markov process reaches a critical region of the state space before a deterministic final time. The underlying idea behind the multilevel splitting methods studied here is to design an embedded sequence of intermediate more and more critical regions, in such a way that reaching an intermediate region, given that the previous intermediate region has already been reached, is not so rare. In practice, trajectories are propagated, selected and replicated as soon as the next intermediate region is reached, and it is easy to accurately estimate the transition probability between two successive intermediate regions. The bias due to time discretization of the Markov process trajectories is corrected using perturbed intermediate regions as proposed by Gobet and Menozzi. An adaptive version would consist in the automatic design of the intermediate regions, using empirical quantiles. However, it is often difficult if not impossible to remember where (in which state) and when (at which time instant) did each successful trajectory reach the empirically defined intermediate region. The contribution of the thesis consists in using a first population of pilot trajectories to define the next threshold, in using a second population of trajectories to estimate the probability of exceeding this empirically defined threshold, and in iterating these two steps (definition of the next threshold, and evaluation of the transition probability) until the critical region is reached. The convergence of this adaptive two-step algorithm is studied in the asymptotic framework of a large number of trajectories. Ideally, the intermediate regions should be defined in terms of the spatial and temporal variables jointly (for example, as the set of states and times for which a scalar function of the state exceeds a time-dependent threshold). The alternate point of view proposed in the thesis is to keep intermediate regions as simple as possible, defined in terms of the spatial variable only, and to make sure that trajectories that manage to exceed a threshold at an early time instant are more replicated than trajectories that exceed the same threshold at a later time instant. The resulting algorithm combines importance sampling and multilevel splitting. Its preformance is evaluated in the asymptotic framework of a large number of trajectories, and in particular a central limit theorem is obtained for the relative approximation error.

Space debris growth and an influx in space traffic will create a need for increased space traffic management. Due to orbital population density and likely future growth, the implementation of a slot architecture to Sun-synchronous orbit is considered in order to mitigate conjunctions among active satellites. This paper furthers work done in Sun-synchronous orbit slot architecture design and focuses on two main aspects. First, an in-depth relative motion analysis of satellites with respect to their assigned slots is presented. Then, a method for developing a slot architecture from a specific set of user defined inputs is derived.

The diploma thesis deals with the behaviour of traffic stream at work zones. It focuses primarily on alternating arranging just before funnelling of the traffic and creation of congestions. The study of parameters defined in the Aimsun program, that examines their effect on alternating arranging in micro-simulation, is a part of the thesis. The right setting of values is verified on traffic model formulated on the basis of video recording. The work aims to minimize effects of necessary repairs and reconstructions of roads by the telematic applications which dynamically affect the traffic stream by changing the maximum speed.

Von Fahrzeugen des Öffentlichen Verkehrs sind deren Positionen bekannt, wenn sie informationstechnisch in ein Betriebsleitsystem eingebunden sind. Über die auf dem Streckenband zwischen Meldepunkten zurückgelegte Wegstecke und die jeweils dafür benötigte Zeit kann auf die mittlere Geschwindigkeit geschlossen werden. Aus dieser wiederum kann eine Verkehrslageaussage abgeleitet werden. In wie weit diese für den Gesamtverkehrsstrom gültig, belastbar und richtlinienkonform ist, welche Randbedingungen für eine Auswertung einzuhalten sind, welche Verfahren sich zur Aufbereitung anbieten und welche Nutzungsszenarien unterstützt werden, wird aufgezeigt.

Thesis(MPAM.) -- University of Limpopo, 2021 / Road traffic injuries negatively impact on the health and the development of the world’s population. The situation is not different in South Africa, particularly in Polokwane, Limpopo Province. In this area, over the past years there has been a steady annual increase of the number of fatalities in the national and provincial roads. This has necessitated the national department of transport to implement mitigating plans with the objective of promoting road safety. It is envisaged that if national road safety plan known as the National Rolling Enforcement Plan (NREP) is clearly defined and effectively implemented, the road fatalities can drastically be reduced. The plan provides some focus areas to be looked at in a way to promote road safety and reduce road accidents. The purpose of this study is to investigate the effectiveness of the NREP, whether it is consistently implemented; and to identify the gaps that affect the implementation process, and to recommend the mitigating factors that will improve the implementation processes of the NREP. A mixed method research approach was used in conducting the study. The first phase entails the collection of quantitative data through structured questionnaires involving traffic officers and traffic managers; while a second phase entails qualitative data collected through focus group discussions that involved traffic officers. The results show the extent at which the traffic officers are involved in the implementation of the NREP. To note, the findings are generalised to the national traffic operations. The study focussed on only one geographical area, namely Limpopo province in South Africa, and not on road transport operations in other parts of the country. Future research should expand on the nationalisation of traffic law enforcement officers.

Les cyber-attaques pourraient engendrer des pertes qui sont de plus en plus importantes pour les utilisateurs finaux et les fournisseurs de service. Ces attaques sont, en outre, élevées par une myriade des ressources infectées et comptent surtout sur les réseaux pour être contrôlées, se propager ou endommager. Face à ces risques, il y a un besoin essentiel qui se manifeste dans la réponse à ces nombreuses attaques par des stratégies de défense efficaces. Malgré les multitudes efforts dévouées pour mettre en œuvre des techniques de défense complètes afin de se protéger contre les attaques réseaux; les approches proposées n’ont pas parvenus à satisfaire toutes les exigences. Les stratégies de défense impliquent un processus de détection complété par des actions de mitigation. Parallèlement à l’importance accordée à la conception des stratégies de détection, il est essentiel de fermer la boucle de sécurité avec des techniques efficaces permettant d’atténuer les impacts des différentes attaques. Dans cette thèse, nous proposons une technique pour réagir aux attaques qui abusent les ressources du réseau, par exemple, DDoS, botnet, distribution des vers, etc. La technique proposée s’appuie sur des approches de gestion du trafic et utilise le standard Multiprotocol Label Switching (MPLS) pour gérer le trafic diagnostiqué comme abusant du réseau, tout en invoquant les processus de détection. Les objectifs de notre technique peuvent être résumés comme suit: d’une part, fournir les moyens — par la qualité de service et schémas de routage — à séparer les flux suspects des légitimes, et d’autre part de prendre le contrôle des flux suspects. Nous bénéficions de l’extension du MPLS au niveau d’inter-domaine pour permettre une coopération entre les fournisseurs, permettant par suite la construction d’un mécanisme de défense à grande échelle. Nous développons un système afin de compléter les aspects de gestion de la technique proposée. Ce système effectue plusieurs tâches telles que l’extraction de données d’alerte, l’adaptation de la stratégie et la configuration des équipements. Nous modélisons le système en utilisant une approche de regroupement et un langage de politiques de sécurité afin de gérer de manière cohérente et automatique le contexte et l’environnement dans lequel la technique de mitigation est exécutée. Enfin, nous montrons l’applicabilité de la technique et du système à travers des différentes simulations tout en évaluant la qualité de service dans des réseaux MPLS. L’application de la technique a démontré son efficacité dans non seulement la mitigation des impacts des attaques mais aussi dans l’offre des avantages financiers aux acteurs de la chaîne de sécurité, à savoir les fournisseurs de service / Cyber attacks cause considerable losses not only for end-users but also service providers. They are fostered by myriad of infected resources and mostly rely on network resources for whether propagating, controlling or damaging. There is an essential need to address these numerous attacks by efficient defence strategies. Researchers have dedicated large resources without reaching a comprehensive method to protect from network attacks. Defence strategies involve first a detection process, completed by mitigation actions. Research on detection is more active than on mitigation. Yet, it is crucial to close the security loop with efficient technique to mitigate counter attacks and their effects. In this thesis, we propose a novel technique to react to attacks that misuse network resources, e.g., DDoS, Botnet, worm spreading, etc. Our technique is built upon network traffic management techniques. We use the Multiprotocol Label Switching (MPLS) technology to manage the traffic diagnosed to be part of a network misuse by detection processes. The goals of our technique can be summarized as follows: first to provide the means — via QoS and routing schemes — to segregate the suspicious flows from the legitimate traffic; and second, to take control over suspicious flows. We profit from the enhancement on the inter-domain MPLS to permit a cooperation among providers building a large-scale defence mechanism. We develop a system to complete the management aspects of the proposed technique. This system performs tasks such as alert data extraction, strategy adaptation and equipments configurations. We model the system using a clustering method and a policy language in order to consistently and automatically manage the mitigation context and environment in which the proposed technique is running. Finally, we show the applicability of the technique and the system through simulation. We evaluate and analyse the QoS and financial impacts inside MPLS networks. The application of the technique demonstrates its effectiveness and reliability in not only alleviating attacks but also providing financial benefits for the different players in the mitigation chain, i.e., service providers