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Measurements and predictions of railway-induced vibrations are becoming a necessity in today’s society where land scarcity causes buildings to be put close to railway traffic. The short distances mean an increased risk of the indoor vibration and noise disturbances experienced by residents. In short, the scope of the project is to investigate the transmission loss and vibration level decrease across various junction geometries. The junctions are modelled in both the Finite Element Method (FEM) and the Dynamic Stiffness Method (DSM). Resonances are avoided when possible by using semi-infinite building components. A two-dimensional model that included Timoshenko beams was set up by Wijkmark [1] and solved using the variational formulation of the DSM by Finnveden [2]. The model is efficient and user-friendly but there is no easy way to adjust the junction geometry since the depths of the walls and the floor slabs are the same. From that study, the current topic was formulated. The results presented in this paper indicate that both the Euler-Bernoulli DS model and the three-dimensional FE model have good potential in describing the vibration transmission across the different junction geometries. The two modelling types show more similar results in the analyses of the bending wave attenuation than in the analyses of the quasilongitudinal wave attenuation. One of the probable causes is that the set length of the Perfectly Matched Layers (PML) is not sufficient at such low frequencies. Larger PMLs require bigger geometries that lead to an increase of the computational time. The other proposed reason is the fact that bending waves are created above the asymmetrical junction when the lower beam is excited by a vertical harmonic force. The flexural displacements are neglected in those cases. The results however, were good enough to be satisfactory. Three junction models were investigated and the attenuation is the highest for both wave types in the case with a beam pair attached to the “middle” of an infinite plate. The attenuation is the second highest across the edge of a semi-infinite plate and the lowest across a junction corner of a semi-infinite plate. As part of the suggested future work, the wave transmission between beam and plate needs to be investigated when Timoshenko beams are included in the DS model. In the Euler-Bernoulli beam theory the cross-section remains perpendicular to the beam axis, which is different to the behaviour of solid elements in FEM.

Optimizing routes for multiple autonomous vehiclesin complex traffic situations can lead to improved efficiency intraffic. Attempting to solve these optimization problems centrally,i.e. for all vehicles involved, often lead to algorithms that exhibitthe curse of dimensionality: that is, the computation time andmemory needed scale exponentially with the number of vehiclesresulting in infeasible calculations for moderate number ofvehicles. However, using a numerical framework called tensordecomposition one can calculate and store solutions for theseproblems in a more manageable way. In this project, we investi-gate different tensor decomposition methods and correspondingalgorithms for solving optimal control problems, by evaluatingtheir accuracy for a known solution. We also formulate complextraffic situations as optimal control problems and solve them.We do this by using the best tensor decomposition and carefullyadjusting different cost parameters. From these results it canbe concluded that the Sequential Alternating Least Squaresalgorithm used with canonical tensor decomposition performedthe best. By asserting a smooth cost function one can solve certainscenarios and acquire satisfactory solutions, but it requiresextensive testing to achieve such results, since numerical errorsoften can occur as a result of an ill-formed problem. / Att optimera färdvägen för flertalet au-tonoma fordon i komplexa trafiksituationer kan leda till effekti-vare trafik. Om man försöker lösa dessa optimeringsproblemcentralt, för alla fordon samtidigt, leder det ofta till algorit-mer som uppvisar The curse of dimensionality, vilket är då beräkningstiden och minnes-användandet växer exponentielltmed antalet fordon. Detta gör många problem olösbara för endasten måttlig mängd fordon. Däremot kan sådana problem hanterasgenom numeriska verktyg så som tensornedbrytning. I det här projektet undersöker vi olika metoder för tensornedbrytningoch motsvarandes algoritmer för att lösa optimala styrproblem,genom att jämföra dessa för ett problem med en känd lösning.Dessutom formulerar vi komplexa trafiksituationer som optimalastyrproblem för att sedan lösa dem. Detta gör vi genom attanvända den bästa tensornedbrytningen och genom att noggrantanpassa kostnadsparametrar. Från dessa resultat framgår det att Sequential Alternating Least Squaresalgoritmen, tillsammans medkanonisk tensornedbrytning, överträffade de andra algoritmersom testades. De komplexa trafiksituationerna kan lösas genomatt ansätta släta kostnadsfunktioner, men det kräver omfattandetestning för att uppnå sådana resultat då numeriska fel lätt kan uppstå som ett resultat av dålig problemformulering. / Kandidatexjobb i elektroteknik 2020, KTH, Stockholm

The main objective in optimizing train control is to eliminate the waste associated with classical design where train separation is determined through the use of "worst case" assumptions to calculate Safe Braking Distances that are invariant to the system. In fact, the worst case approach has been in place since the beginning of train control systems. Worst case takes the most conservative approach to the determination of train stopping distance, which is the basis for design and capacity of all train control systems. This leads to stopping distances that could be far more than actually required under the circumstances at the time the train is attempting to brake. A new train control system is proposed that utilizes information about the train and the conditions ahead to optimize and minimize the Safe Braking Distance. Two methods are proposed to reduce safe braking distance while maintaining an appropriate level of safety for the system. The first introduces a statistical method that quantifies a braking distance with various hazards levels and picks a level that meets the safety criteria of the system. The second method uses train mounted sensors to determine the adhesion level of the wheel and rail to determine the appropriate braking rate for the train under known circumstances. Combining these methods provides significant decreases in Safe Braking Distances for trains. A new train control system is utilized to take advantage of these features to increase overall system capacity. / Electrical and Computer Engineering

Concerns with emissions, CO2 in particular, and energy resource associated with conventional internal combustion engine (ICE) vehicles is motivating a shift towards more electrified power-trains for road transportation, as well as other transportation applications. The modelling, characterization and design of electrified power-trains, including energy storage technologies, traction machine technologies and their associated power electronics, are discussed in this thesis. Port cranes are a special case of land transportation encompassing many of the power-train objectives found common with road based hybrid electric vehicles; here a port crane system is studied. The power flow for a typical crane loading cycle is analyzed and the value of the energy consumption and saving potential is calculated. Then alternative energy storage applications are considered for hybrid power-train configurations employing diesel engine generators, battery packs, supercapacitors (SCs), and flywheels. A hybrid rubber tyred gantry crane (RTGC) power-train model with power management is developed and the battery-SC hybrid energy storage systems are designed for both short- and long-period operation. The Induction machine (IM) is a popular technology for traction applications. Although many publications discuss IM design to realize a traction torque-speed characteristic, the IM model is studied to determine the main parameters impacting on the machine performance capability at constant torque and extended speed. Based on the model analysis, an IM design procedure for traction applications is proposed which improves machine performance capability. The machine design parameters are normalized in per unit form and hence the proposed design procedure is applicable across different ratings. In the specification and definition of vehicle power-trains, it is common (in industry) to quote data at specific operating conditions, for example, full or fixed battery terminal voltage and system temperature. The interactive influence between energy storage devices and the vehicle system is investigated. Using the all-electric Nissan Leaf power-train as a reference example, the Nissan Leaf traction system is evaluated and performance assessed by considering DC-link voltage variation from battery full state of charge (SoC) to zero SoC and temperature variations typical of an automotive application, showing that the system stated performance is reduced as battery SoC decreases. An alternative traction machine design is proposed to satisfy the vehicle target performance requirements over the complete variation of SoC. The vehicle power-train is then modified with the inclusion of a DC/DC converter between the vehicle battery and DC-link to maintain the traction system DC-link voltage near constant. A supercapacitor system is also considered for improved system voltage management. The trade-offs between the actual Nissan Leaf power-train and the redesigned systems are discussed in terms of electronic and machine packaging, and mitigation of faulted operation at high speeds. Using the Nissan Leaf interior permanent magnet (IPM) machine as the benchmark machine, an example surface permanent magnet (SPM) machine, with same design constraints, is designed and compared with the benchmark IPM machine. The phase voltage distortion of IPM and SPM machines are compared and the mechanisms are revealed. An alternative machine topology with pole shoe rotor is proposed for reduction of machine peak current rating and voltage distortion. The pole shoe topology is common in industrial variable speed drives employing constant torque regimes, but not for traction. Here, the machine with pole shoe rotor is designed to achieve traction performance. The pole shoe concept for vehicle traction is significantly different from existing practice in the electric and hybrid electric automotive industry and thus departure in standard design is a contribution of this thesis. / Thesis / Doctor of Philosophy (PhD)

Downtown Blacksburg, Virginia, is defined by the presence of the townâ s original sixteen blocks, situated in a four x four square gridded arrangement. The edges of the downtown area are loosely bounded by unique natural and architectural markers and by rules for urban development that contribute to the architectural vernacular of the town. Public spaces are activated by the company of these markers, and sometimes by the repudiation of the urban rules, and thus a secondary reading of public occupation within the downtown sphere manifests itself. This thesis project attempts to identify and analyze the rules and characteristics of Blacksburgâ s urbanity and to project those rules into a new feature of the downtown foursquare grid. A train station that occupies the vicinity of the historic â Huckleberryâ rail line characterizes, defines, and augments the public regions of downtown Blacksburg. / Master of Architecture

Through this thesis I explore how a train station can serve as the platform for an experience that is more profound than simply coming and going, and instead can provide a moment that allows travelers to appreciate the location that they are traveling to or from. A train station is almost uniquely positioned to serve as the first or last building any train traveler encounters in a city, serving as the gateway to the modern city. This presents an opportunity where the station itself will have a direct influence on a traveler's initial or final experience of the city. And so, I propose a station that, through its architecture and relationship to the site, provides the traveler a space where they can stop, look, and take in the view of the city from which they are about to depart or at which they are just now arriving. It allows those new to the city to get an understanding of the basic urban layout and its relationship to its surroundings. It becomes a destination in itself, that allows the local population to regain knowledge of their city and to reinterpret what they already know about their home. / Master of Architecture

Thesis advisor: John A. Baldwin / We classify genus-two L-space knots in S3 and the Poincare homology sphere.This leads to the first and to-date only detection results in knot Floer homology for knots of genus greater than one. Our proofs interweave Floer-homological properties of L-space knots, the geometry of pseudo-Anosov maps, and the theory of train tracks and folding automata for braids. The crux of our argument is a complete classification of fixed-point-free pseudo-Anosov maps in all but one stratum on the genus-two surface with one boundary component. To facilitate our classification, we exhibit a small family of train tracks carrying all pseudo-Anosov maps in most strata on the marked disk. As a consequence of our proof technique, we almost completely classify genus-two, hyperbolic, fibered knots with knot Floer homology of rank 1 in their next-to-top grading in any 3-manifold. Several corollaries follow, regarding the Floer homology of cyclic branched covers, SU(2)-abelian Dehn surgeries, Khovanov and annular Khovanov homology, and instanton Floer homology. / Thesis (PhD) — Boston College, 2024. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Mathematics.

An attempt was made to reduce fuel costs of a diesel-electric locomotive by operating the locomotive in a periodic manner, as opposed to operating at a constant velocity. The periodic operation consisted of accelerating the locomotive in a high throttle position and then deccelerating at a low throttle position. An SD40 Locomotive was modeled to test the periodic operation. The periodic operation was actually found to offer no improvement in fuel performance over that of constant velocity operation. A modification to the diesel engine that takes advantage of the periodic operation is suggested that will give a better fuel performance. The modification to the engine would not be possible with constant velocity operation. With the modification, the periodic operation was found to save fuel over the constant velocity operation. A controller was then designed to implement the periodic operation. The key component of the controller is an observer to determine unknown hill forces. The controller was found to work successfully. / M.S.

Harsh winter climate causes various problems for both the public andprivate sector in Sweden, especially in the northern part and the railway industryis no exception. This master thesis project covers an investigation of the eects ofthe winter climate and a phenomena called atmospheric icing on the performance ofthe train in a region called the Botnia-Atlantica region. The investigation was donewith data over a short period January-February 2017 with simulated weather datafrom the Weather research and forecast model that was compared with the periodOctober - December 2016. The investigation only included high speed trains.The trains have been analysed based on two dierent performance measurements.The cumulative delay which is the increment in delay over a section and the currentdelay which is the current delay compared to the schedule. Cumulative delaysare investigated with survival analysis and the current delay is investigated with aMulti-state Markov model.The results show that the weather could have an eect on the trains performancewhere the survival analysis detected connection between the weather and cumulativedelays. The Markov model also showed a connection between the weather anddelayed trains including that the presence of atmospheric icing had a negative eecton remaining in a state of non-delay.