Σκοπός της παρούσας διπλωματικής εργασίας είναι ο σχεδιασμός ενός ελεγκτή πέδησης για την ρυμουλκόμενη μονάδα μιας νταλίκας, ώστε αυτή να μην αποκλίνει της πορείας της κατά το φρενάρισμα. Αναλυτικότερα, στο κεφάλαιο 1 παρουσιάζεται η μορφή των τυπικών και πιο συνηθισμένων ρυμουλκόμενων οχημάτων (οδικά τρένα) και ορίζονται τα βασικά κομμάτια που το αποτελούν. Στο κεφάλαιο 2 παρουσιάζονται με χρήση κατάλληλων μαθηματικών και φυσικών προτύπων οι ταχύτητες και οι επιταχύνσεις καθώς και τα διάφορα συστήματα συντεταγμένων που απαιτούνται για την περιγραφή της κίνησης του οχήματος. Στο κεφάλαιο 3 αναλύεται το σύνθετο αλλά και το απλουστευμένο μοντέλο των οδικών τρένων, ενώ στο κεφάλαιο 4 αναλύουμε το δυναμικό μοντέλο του οχήματος tractorsemitrailer που αποτελεί και το αντικείμενο έρευνας της εργασίας. Υπολογίζουμε πλήρως τις εξισώσεις που περιγράφουν το σύστημα, με βάση κάποιες προϋποθέσεις όπως ότι κινείται στην ευθεία, με σταθερή διαμήκη ταχύτητα ενώ επίσης δεχόμαστε και το γραμμικό μοντέλο για τα ελαστικά. Τέλος, στο κεφάλαιο 5 σχεδιάζουμε ένα PD ελεγκτή και βρίσκουμε τις βέλτιστες τιμές των παραμέτρων του ώστε το σύστημα μας να παρουσιάζει όσο το δυνατόν μικρότερα σφάλματα. / Aim of present diplomatic work is the planning of controller of braking for the followinf unit of lorry, in order that this does not deviate her course at the break. More analytically, in capital 1 is presented the form the formal and more usual road trains and is fixed the basic pieces where constituting. In capital 2 are presented with use suitable mathematic and natural models the speeds and the accelerations as well as the various systems of coordinates that are required for the description of movement of vehicle. In capital 3 is analyzed the complex but also simplified model of road trains, while in capital 4 we analyze the dynamic model of vehicle tractorsemitrailer that is the subject of this work. We calculate the equations that describe the system, with base certain conditions as that it is moved in the straight line, with constant speed while also we accepted the linear model for the tyres. Finally, in capital 5 we draw a PD controller and we find the most optimal prices of parameters in order that our system presents as much as possible smaller faults.

Cette thèse porte sur l'ordonnancement des trains dans les gares complexes en forte densité de circulation. L'objet se situe à la réalisation d'un outil pour aider les managers de la gare à générer un tableau des horaires sans-conflits dans un journée. Le management des circulations ferroviaires dans la gare demande l'ordonnancement soigneux pour adapter les ressources limités, en évitant les conflits entre les trains et satisfaisant l'objectif et les politiques économiques et de la sécurité en même temps. D'après les méthodes appliquées en recherche opérationnelle et les expériences professionnelles, une modèle mathématique applicable aux gares différentes est construit pour formaliser le problème de l'ordonnancement des trains contenant la topologie de la gare, activités des trains, contraintes de planification et objectives. Comme un problème à grande échelle, l'ordonnancement des trains dans un journée est décomposé en sous-problèmes traitables dans l'ordre du temps par sliding window algorithme accumulé. Chaque sous-problème est résolu par branch-and-bound de CPLEX. Afin d'accélérer le calcul des sous-problèmes, tri-level optimisation méthode est construit pour offrir une solution optimale locale dans un temps de calcul assez court. Cette solution est donnée à branch-and-bound comme une solution initiale.Ce système consiste à vérifier la faisabilité des horaires donnés à la gare. Les trains avec les conflits insolvables sont retournés à l'origine de ces trains avec les modifications des heures proposées. Déviations des trains commerciaux sont minimisées pour diminuer la propagation du délai dans le réseau ferroviaire. / This thesis focuses on the trains platforming problem within busy and complex railway stations and aims to develop a computerized dispatching support tool for railway station dispatchers to generate a full-day conflict-free timetable. The management of rail traffic in stations requires careful scheduling to fit to the existing infrastructure, while avoiding conflicts between large numbers of trains and satisfying safety or business policy and objectives. Based on operations research techniques and professional railway expertise, we design a generalized mathematical model to formalize the trains platforming problem including topology of railway station, trains' activities, dispatching constraints and objectives. As a large-scale problem, full-day platforming problem is decomposed into tractable sub-problems in time order by cumulative sliding window algorithm. Each sub-problem is solved by branch-and-bound algorithm implemented in CPLEX. To accelerate calculation process of sub-problems, tri-level optimization model is designed to provide a local optimal solution in a rather short time. This local optimum is provided to branch-and bound algorithm as an initial solution.This system is able to verify the feasibility of tentative timetable given to railway station. Trains with unsolvable conflicts will return to their original activity managers with suggestions for the modification of arrival and departure times. Time deviations of commercial trains' activities are minimized to reduce the delay propagation within the whole railway networks.

M.A. / The proposal to build the Gautrain rapid-rail link between Pretoria, Johannesburg and Johannesburg International Airport was approved in June 2000 by the Gauteng Provincial Government. It was noted that this particular development could have serious environmental implications for the area involved. The aim of this research is therefore to identify the most suitable terrain in order to optimise the rail route alignment with minimal environmental impact. This will be accomplished by undertaking a terrain suitability analysis. The different high-speed railway types are discussed and their impact on the environment is considered, culminating in an evaluation of the background and status of the proposed Gautrain rapid-rail link. The different approaches to terrain evaluation are discussed in order to draw conclusions relative to the methodology used in this research. Subsequently the activity approach as described by Mitchell (1991) and Hugo et al (1997) was chosen as the methodology to use for this research and the terrain within the study area was classified according to its suitability for the development of the Gautrain rapid-rail link. A Geographic Information System (GIS) was utilised to aid in the terrain suitability analysis. As a result of the analysis an optimised route is proposed and compared to the rail routes already proposed for the Gautrain rapid-rail link. It is imperative that a terrain suitability analysis should form part of the preliminary phase of any environmental management cycle as portrayed in Fuggle & Rabie (1998), in order to identify suitable terrain for the development in question; the rapid-rail link route should be no exception.

Recently-developed technologies for monitoring activity in populations of neurons make it possible for the first time, in principle, to ask many basic questions in neuroscience. However, computational tools for analyzing newly available data need to be developed. The goal of this thesis is to contribute to this effort by focusing on two specific problems. First, we used a point-process regression framework to provide a methodology for statistical assessment of the link between neural spike synchrony and network-wide oscillations. In simulations, we showed that our method can recover ground-truth relationships, and in two types of spike train data we illustrated the kinds of results the method can produce. The approach improves on methods in the literature and may be adapted to many different experimental settings. Second, we considered the problem of source extraction in calcium imaging data, i.e., the detection of neurons within a field of view and the extraction of each neuron’s activity. The data we mainly focus on are recorded with a microendoscope, which has the unique advantage of imaging deep brain regions in freely behaving animals. These data suffer from high levels of background fluorescence, as well as the potential for overlapping neuronal signals. Based on the existing constrained nonnegative matrix factorization (CNMF) framework, we developed an efficient method to process microendoscopic data. Our method utilizes a novel algorithm to initialize the spatial shapes and temporal activity of the neurons from the raw video data independently from the strong fluctuating background. This step ensures the efficiency and accuracy of solving a nonconvex CNMF problem. Our method also models the complicated background by including its low-spatial frequency structure and the locally-low-rank feature to avoid absorbing cellular signals into the background term. We developed a tractable solution to estimate the background activity using this new model. After subtracting the approximated background, we followed the CNMF framework to demix neural signals and recover denoised and deconvolved temporal activity. We optimized several algorithms in solving the CNMF problems to get accurate results. In practice, our method outperforms all existing methods and has been adopted by many experimental labs.

This thesis examines the relationship between Korean film and modernity by conducting a survey of the representation of cars, trains, and the city throughout (South) Korean film history. There have been several remarkable changes in these representations over time: the train, first the awe-inspiring symbol of Korean technological advancement in the 1890s, becomes the brutal symbol of Japanese oppression just a few decades later. The city in Korean film is politically and socially charged for most of the 20th century, a place where innocent people are morally corrupted or physically assaulted. But by the 21st century, trains and cars are now toys for action characters to manipulate, and the city is now a neutral backdrop for pure entertainment in blockbuster films such as Train to Busan (Yeon Sang-ho, 2016), Ashfall (Lee Hae-jun and Kim Byung-seo, 2019), and Peninsula (Yeon Sang-ho, 2020). There are several reasons for this, one of which I propose as the inherently procapitalist and pro-modernity nature of the blockbuster film.

It is accepted that defective structural designs are mostly caused by insufficient knowledge of input data, such as material properties or loading, rather than inadequate analysis or testing methods. In particular, loads associated with automotive and transport (trucks, trailers, containers, trains) structures are nontrivial to quantify. Such loads arise from stochastic and ill-defined processes such as driver/operator actions and structure-terrain interaction. The fundamental processes involved with the determination of input loading are measurements, surveys, simulation, estimation and calculation from field failures. These processes result in design criteria, code requirements and/or testing requirements. The present study deals with methods for the establishment of input loading for automotive and transport structures. It is attempted to generalise and unify new and existing techniques into a cohesive methodology. This is achieved by combining researched current theory and best practices, with lessons learned during application on, as well as new techniques developed for, a number of complex case studies, involving road tanker vehicles, light commercial vehicles, industrial vehicles, as well as tank containers. Apart from the above, the present study offers four individual, unique contributions. Firstly, two methods, widely applied by industry, namely the Remote Parameter Analysis (RPA) method, which entails deriving time domain dynamic loads by multiplying measured signals from remotely placed transducers with a unit-load static finite element based transfer matrix, as well as the Modal Superposition method, are combined to establish a methodology which accounts for modal response without the need for expensive dynamic response analysis. Secondly, a concept named Fatigue Equivalent Static Load (FESL) is developed, where fatigue load requirements are derived from measurements as quasi-static g-loads, the responses to which are considered as stress ranges applied a said number of times during the lifetime of the structure. In particular, it is demonstrated that the method may be employed for multi-axial g-loading, as well as for cases where constraint conditions change during the mission of the vehicle. The method provides some benefits compared to similar methods employed in the industry. Thirdly, a complex analytical model named Two Parameter Approach (TPA) is developed, defining the usage profile of a vehicle in terms of a bivariate probability density distribution of two parameters (distance/day, fatigue damage/distance), derived from measurements and surveys. Based on an inversion of the TPA model, a robust technique is developed for the derivation of such statistical usage profiles from only field failure data. Lastly, the applicability of the methods is demonstrated on a wide range of comprehensive case studies. Importantly, in most cases, substantiation of the methods is achieved by comparison of predicted failures with ‘real-world’ failures, in some cases made possible by the unusually long duration of the study. / Thesis (PhD (Mechanical Engineering))--University of Pretoria, 2007. / Mechanical and Aeronautical Engineering / PhD / Unrestricted

The purpose of this thesis was to trace the pattern of Mormon immigration from Europe and the eastern United States during the decade of the 1860s. Although the initial Mormon migration of 1847 has recieved extensive attention from historians, later organized movements into the Great Basin by immigrant Mormon groups has remained virtually untouched. This thesis traces the formation, organization, and implementation of the church train emigration from Europe and the eastern United States. Also, it details its organization from the church hierarchy, as well as the extensive participation by the Mormon population as a whole. A primary focus of the thesis centered on the pervasive comraderie and sacrifice of the Mormons living in Utah. With the pragmatic leadership of Brigham Young, coupled with the superb organizational apparatus of the church train system, the Mormon church was afforded the opportunity to aid more than twenty thousand converts to immigrate to Utah Territory from 1861-1868. In addition, this study concerned itself with an unprecedented occurrence in the field of nineteenth century transportation. By utilizing the church train system adroitly, the Mormons were the first and only organization to journey both to and from the Missouri River (with large emigrant companies), in one season. This was an extremely important breakthrough in nineteenth century transportation and deserves greater attention from historians. The history of the church train emigration was both unique and successful. It presents a prime example of Mormon organizational abilities in the face of complex and difficult impediments.

Dans les recherches réalisées pour ce projet de thèse, il est démontré qu’une traverse existante de train d’atterrissage d’hélicoptère à patins fabriquée par pliage et érosion chimique, pourrait être remplacée par une autre traverse, dont la forme innovante est fabricable par le procédé d’hydroformage de tubes. Ce procédé présente par exemple l’avantage d’être plus respectueux de l’environnement que le procédé de fabrication actuel, car il ne nécessite pas l’utilisation de produits chimiques polluant. De plus, la méthodologie développée dans le cadre des recherches réalisées permet de prendre en compte l’histoire du matériau de la traverse dans toutes les étapes de son processus de fabrication. Les performances d’un train d’atterrissage équipé de la nouvelle traverse ont été évaluées numériquement. Des travaux, développés avec le logiciel de calculs par éléments finis ABAQUS, ont permis de mettre en évidence l’intérêt d’utiliser des éléments finis de coque solides fiables et précis. Ces éléments sont en effet capables de prendre en compte le comportement dans l’épaisseur de structures minces avec une seule couche d’éléments. Une nouvelle technique de lissage appelé «Smoothed finite element method» ou «SFEM» a retenu l’attention pour sa simplicité de mise en œuvre et son insensibilité à la distorsion de maillage parfois rencontrée dans les simulations de formage de formes complexes. Un élément de coque solide résultant linéaire développé en utilisant cette méthode SFEM pour traiter de la cinématique en membrane et en flexion a été testé avec succès au travers d’exemples classiques identifiés dans la littérature. Ce nouvel élément a montré un niveau de précision souvent supérieur à celui d’autres éléments déjà existants. En outre, un élément de coque solide à intégration réduite, capable de fonctionner avec la plupart des lois de comportement en trois dimensions et cela même en présence de structures minces a été développé. Cet élément, libre de tout blocage a montré un bon niveau de précision par rapport aux éléments existants dans le cas de problèmes implicites géométriquement linéaires et non-linéaires. L’élément a été étendu en formulation explicite puis couplé avec une loi de comportement hyper élastoplastique en trois dimensions. Il a enfin été testé dans une simulation d’hydroformage de tubes en présence de pressions élevées, de frottement et de grandes déformations. / In the current work, it is shown that an existing helicopter skid landing gear cross tube, made by tube bending and chemical milling, could be replaced by another cross tube, whose innovative shape is producible by tube hydroforming. This method has for example the advantage of being more environmentally friendly than the current manufacturing process, because it does not require the use of hazardous chemicals. In addition, the methodology developed in this project takes into account the cross tube material’s history throughout the manufacturing process. Moreover, the performance of a skid landing gear equipped with this new cross tube has been evaluated numerically. This thesis simulation work has been developed with the finite element analysis software ABAQUS. It highlights the potential gains of using a reliable and accurate solid-shell finite element which is capable to take into account the through-thickness behavior of thin structures with a single layer of elements. A new smoothing technique called «Smoothed finite element method» or «SFEM» has been considered for its simplicity and insensitivity to mesh distortion, sometimes encountered while simulating complex shapes forming. A new resultant linear solid-shell element using this SFEM to deal with membrane and bending kinematics has been developed and successfully tested through classical benchmark problems found in the literature. This new element has often shown much greater level of accuracy than other existing elements. In addition, a novel reduced integration solid-shell element, able to work with most three dimensions constitutive laws even in the presence of thin structures is also discussed. This element, free of locking, shows a good accuracy level with respect to existing elements in implicit geometrically linear and non-linear benchmark problems. Its extension to explicit formulation is coupled with a three dimensions hyper elastoplastic constitutive law and tested in a tube hydroforming simulation involving high pressures, friction and large deformations.

Défini par la loi portant réforme ferroviaire du 4 août 2014 comme « l’ensemble des moyens humains et matériels mis en œuvre sur le réseau ferré national pour assurer sa gestion et l’exécution des services de transport l’utilisant », le ferroviaire est un système composé de multiples dimensions. Dans ce cadre, cette thèse s’efforce d’analyser sous un angle forcément transdisciplinaire les relations entre les différentes composantes du système ferroviaire, afin de le rendre intelligible. En complétant cette approche empirique par la modélisation du fonctionnement des services ferroviaires conventionnés de voyageurs, captant la majorité des fonds publics alloués au secteur, il s’agit également de contribuer à la compréhension du système ferroviaire et de ses enjeux contemporains, au bénéfice de ses décideurs, et tout particulièrement les autorités publiques. / The current government’s legislation to restructure the rail sector defines the national rail system as a complex system composed of “all the human and material means implemented on the national rail network in order to ensure the management and delivery of transport services using it”. Within this framework, this thesis attempts to analyze in a necessarily interdisciplinary perspective the relationship between the different components of the rail system, in order to make it intelligible. It aims to contribute to understanding the railway system and its current issues, by completing this empirical based approach to modeling the public service obligations, which represent most of the traffic and publics funds on the French rail network

This thesis aims to analyse passenger rail transport and its importance nowadays, mainly in the international context. It sums up the obstacles that negatively affect the competitiveness of railways and how the European Union copes with this issue. The practical part of the thesis focuses on long-distance rail services, such as night trains and car trains. It includes an analysis of the services provided by two European rail operators and seeks to provide an insight into the customer decision-making process between rail and car transportation.