This study includes an experimental evaluation of a prototype trailing-arm suspension for heavy trucks. The primary goal of this new suspension is to match or improve the kinematics and dynamic performance of an existing "Z-bar" suspension. Significant reductions in cost, weight, and number of parts are the main reasons for this redesign. A permanent facility is constructed to support the testing of different heavy truck suspensions. For actuation of the vehicle suspension, hydraulic actuators are used in the kinematics tests in a quasi-dynamic manner. For the dynamic tests, the vehicle is excited using two hydrodynamic actuators. A collection of forces, displacements, velocities, and accelerations are measured during the tests using transducers that were installed on the suspension and test vehicle. The test measurements are analyzed in both time and frequency domains and then the results of the two suspensions were compared to establish the dynamic merits of the prototype suspension. The kinematics tests include vertical stiffness, roll stiffness, and roll steer measurements for each suspension. The results from the kinematics tests show that the trailing-arm suspension exhibits kinematics traits that are quite similar to the "Z-bar" suspension, within the context of the tests conducted in the study. The dynamic testing consists of three input signals commonly used for such tests, namely: a chirp signal input, a step signal input, and a range of pure tone inputs. The test results show that the resonant frequencies of the two primary suspensions differ by an amount that is most likely too small to affect ride dynamics. The two suspensions, however, exhibit significantly different damping characteristics. The new suspension has much less frictional damping than the existing suspension. This is expected to provide better ride characteristics, assuming that the primary dampers (shock absorbers) are properly tuned for the vehicle that the new suspension was designed for. / Master of Science

Existing literature on the relationship between ridehailing (RH) and transit services is limited to empirical studies that rely on self-reported answers and lack spatial and temporal contexts. To fill this gap, the research takes a novel approach that uses real-time geospatial analyzes. Using this approach, we estimate the extent to which ride-hailing services have contributed to the recent decline in public transit ridership. With source data on ridehailing trips in Chicago, Illinois, we computed the real-time transit-equivalent trip for the 7,949,902 ridehailing trips in June 2019; the sheer size of this sample is incomparable to the samples studied in existing literature. An existing Multinomial Nested Logit Model was used to determine the probability of a ridehailer selecting a transit alternative to serve the specific origin-destination pair, P(Transit|CTA) . The study found that 31% of RH trips are replaceable, 61% are not replaceable, and 8% lie within the buffer zone. We measured the robustness of this probability using a parametric sensitivity analysis, and performed a two-tailed t-test, with a 95% confidence interval. In combination with a Summation of Probabilities, the results indicate that the total travel time for a transit trip has the greatest influence on the probability of using transit, whereas the airport pass price has the least influence. Further, the walk time, number of stops in the origin and destination census tracts, and household income also have significant impacts on the probability of using transit. Lastly, we performed a Time Value Analysis to explore the cost and trip duration difference between RH trips and their transit-equivalent trips on the probability of switching to transit. The findings demonstrated that approximately 90% of RH trips taken had a transit-equivalent trip that was less expensive, but slower. The main contribution of this study is its thorough approach and fine-tuned series of real-time spatial analyzes that investigate the replaceability of RH trips for public transit. The results and discussion intend to provide perspective derived from real trips and encourage public transit agencies to look into possible opportunities to collaborate with ridehailing companies. Moreover, the methodologies introduced can be used by transit agencies to internally evaluate opportunities and redundancies in services. Lastly, we hope that this effort provides proof of the research benefits associated with the recording and release of ridehailing data. / Master of Science / Existing literature on the relationship between ridehailing (RH) and transit services is limited to empirical studies that rely on self-reported answers and lack spatial and temporal contexts. To fill this gap, the research takes a novel approach that uses real-time geospatial analyzes. Using this approach, we estimated the extent to which ride-hailing services have contributed to the recent decline in public transit ridership. With source data on ridehailing trips in Chicago, Illinois, we computed the real-time transit-equivalent trip for the 7,949,902 ridehailing trips in June 2019; the sheer size of this sample is incomparable to the samples studied in existing literature. An existing Multinomial Nested Logit Model was used to determine the probability of a ridehailer selecting a transit alternative to serve the specific origin-destination pair, P(Transit|CTA) . The study found that 31% of RH trips are replaceable, 61% are not replaceable, and 8% lie within the buffer zone. We measured the robustness of this probability using a parametric sensitivity analysis, and performed a two-tailed t-test, with a 95% confidence interval. In combination with a Summation of Probabilities, the results indicate that the total travel time for a transit trip has the greatest influence on the probability of using transit, whereas the airport pass price has the least influence. Further, the walk time, number of stops in the origin and destination census tracts, and household income also have significant impacts on the probability of using transit. Lastly, we performed a Time Value Analysis to explore the cost and trip duration difference between RH trips and their transit-equivalent trips on the probability of switching to transit. The findings demonstrated that approximately 90% of RH trips taken had a transit-equivalent trip that was less expensive, but slower. The main contribution of this study is its thorough approach and fine-tuned series of real-time spatial analyzes that investigate the replaceability of RH trips for public transit. The results and discussion intend to provide perspective derived from real trips and encourage public transit agencies to look into possible opportunities to collaborate with ridehailing companies. Moreover, the methodologies introduced can be used by transit agencies to internally evaluate opportunities and redundancies in services. Lastly, we hope that this effort provides proof of the research benefits associated with the recording and release of ridehailing data.

The increasing penetration of inverter based renewable generation in the form of solar photo-voltaic (PV) or wind has introduced numerous operational challenges and uncertainties. Among these challenges, one of the major ones is the impact on the transient stability of the grid. On the other hand, the direct methods for transient stability assessment of power systems have also fairly evolved over the past 30 years. These set of techniques inspired from the Lyapunov's direct method provide a clear insight into the system stability changes with a changing grid. The most attractive feature of these types of techniques is the heavy reduction in the computational burden by cutting down on the simulation time. These advancements were still aimed at analyzing the stability of a non-linear autonomous dynamical system and the existing power system perfectly fits that definition. Due to the changing renewable portfolio standards, the power system is undergoing serious structural and performance alterations. The whole idea of power system stability is changing and there is a major lack of work in the field of direct methods in keeping up with these changes. This dissertation aims at employing the pre-existing direct methods as well as developing new techniques to visualize and analyze the stability of a power system with an added subset of complexities introduced by PV generation. / Ph. D. / The increasing penetration of inverter based renewable generation in the form of solar photo-voltaic (PV) or wind has introduced numerous operational challenges and uncertainties. Among these challenges, one of the major ones is the impact on the transient stability of the grid. A set of techniques called the direct methods significantly cut down the simulation time required for transient stability studies. However, these techniques did not keep up with the changing power system dynamics due to renewable generation and thus there is a need to develop new methods to study this changing system which is the aim of this thesis.

Background: In recent years, the Swedish taxi industry has undergone a number of changes as a result of increased digitalisation in a deregulated market. Most market players have emerged as a result of the freedom of establishment, which in turn has led to higher competition. Among these new entrants, the ride-hailing business model has had an impact by taking a traditional service and performing it differently. This thesis will thus examine how this approach has affected the Swedish taxi industry in more detail. Purpose: The thesis aims to increase understanding of the aspects of the ride-hailing business model that are specifically distinguished by the company Uber. The following secondary purpose is to identify the impact this specific business model has on the Swedish taxi industry as a result of Uber's establishment on the Swedish market. Method: The thesis is an abductive case study of qualitative character. The empirical data has been collected through three distinct approaches, which are the collection of scientific material, semi-structured interviews with three respondents and a Social Media Analysis consisting of data from approximately 100 independent articles and media publications. Furthermore, these three types of empirical data have been selected via a strategic selection. Conclusion: The result of this thesis shows that the specific aspects that stand out in Uber Sweden's use of the ride-hailing business model are value creation, differentiation, innovation and social acceptance. The results also show that the ride-hailing business model has influenced the Swedish taxi industry in terms of the specific aspects' influence on the development of the taxi market and on government regulations. / Bakgrund: Under de senaste åren har den svenska taximarknaden genomgått en rad förändringar till följd av en ökad digitalisering på en avreglerad marknad. Det har uppkommit flertalet aktörer på marknaden till följd av den fria etableringsrätten, som i sin tur lett till en högre konkurrens. Bland dessa nya aktörer har affärsmodellen ride-hailing fått ett genomslag genom att ta en traditionell tjänst och utföra den annorlunda. Uppsatsen kommer därmed att närmare undersöka hur detta tillvägagångssätt har påverkat den svenska taximarknaden. Syfte: Uppsatsen syftar till att öka förståelsen för de aspekter av ride-hailing-affärsmodellen som specifikt utmärker sig hos företaget Uber. Det följande sekundära syftet avser att identifiera den påverkan som denna specifika affärsmodell haft på den svenska taxibranschen till följd av Ubers etablering på den svenska marknaden. Metod: Uppsatsen är en abduktiv fallstudie av kvalitativ karaktär. Empiri har insamlats via tre distinkta tillvägagångssätt, vilka är insamlande av vetenskapligt material, semistrukturerade intervjuer med tre respondenter samt en Social Media Analys bestående av data från cirka 100 fristående artiklar samt mediala publikationer. Vidare har dessa tre typer av empiriska data valts ut via ett strategiskt urval. Slutsats: Resultatet från denna uppsats visar att de specifika aspekterna som utmärker sig inom Uber Sveriges användning av ride-hailing-affärsmodellen är värdeskapande, differentiering, innovation och social acceptans. Vidare visar resultatet på att ride-hailing-affärsmodellen har påverkat den svenska taximarknaden i avseende på de specifika aspekternas inflytande på utvecklingen av taxibranschen samt kring statliga regleringar.

Made available in DSpace on 2016-12-23T14:05:56Z (GMT). No. of bitstreams: 1 patricia rodrigues parte 1 p 1-46.pdf: 620096 bytes, checksum: 2df2214171a193891fb63f38e815ac0e (MD5) Previous issue date: 2011-09-16 / Problems that deal with wheelchair users public transportation are often solved by Dial a Ride Problem (DARP) with time window (Time Window TW). The goal of this type of problem is the minimization of the operation cost, in other words, the ride time respecting constraints like time windows for pickup and delivery of each user, the number of vehicles available and each vehicle capacity. This thesis proposes an exact Mixed Integer Linear Program model to solve the DARPTW. In order to apply the model in a real application, the model was tested with data provided by the Vitória City Hall Infrastructure and Transportation Secretary. The model was implemented using CPLEX software and the results showed that instances up to 20 wheelchair users can be solved optimally. Moreover, it was done an analysis for fleet used / Os problemas de transporte público de cadeirantes são comumente resolvidos pelo modelo Dial-a-Ride Problem (DARP) com janelas de tempo (Time Window - TW). Com base nas restrições de janela de tempo na origem e no destino de cada cliente, no número de veículos e na capacidade de cada um deles, deseja-se minimizar os custos de atendimento dessas demandas, ou seja, o tempo de viagem. A presente dissertação propõe um modelo de Programação Linear Inteira Mista para resolver o problema do DARP-TW. Visando uma aplicação do modelo no transporte público de cadeirantes foram utilizados dados reais fornecidos pela Secretaria de Transportes, Trânsito e Infraestrutura da Prefeitura de Vitória. O modelo foi executado no software CPLEX e os resultados mostraram que cenários com até 20 clientes podem ser resolvidos otimamente. Além disso, foi possível uma análise em relação à frota utilizada

The subject of diploma thesis is a blue-print of appropriate adjustment space by the railway station in Brno Řečkovice, in terms of road structures, so that it meets all requirements of public transfer terminal and IDS JMK. Terminal should server as a transfer station between bus service and pojected North-Southern Rail Diameter. In the terminal, there should be a continuity on systems P+R, K+R and B+R ensured. The project is dealing with a partial design of adjacent local roads. The work is processed in AutoCAD 2011, Bentley InRoads and Microsoft Office 2007.

As urban growth accelerates and the need to address environmental issues regardingtransportation is larger than ever and many policymakers have chosen to adapt park and rideas one of their methods to reduce car traffic. However, the effect from adapting the policy isnot very well understood and since the policy can directly conflict with other policies relatedto land use it is important to know which effects can be expected. By knowing which effectsto expect, policy makers can make more sustainable choices in their policy adaption.This study has been carried out using data from two different counties to find out if theeffects from park and ride differ depending on the type of environment it serves. Further, anadditional analysis has been done using temporal data to measure the effect of adapting orexpanding a park and ride facility at a public transport station or stop.It was found that in a rural setting, the relation between park and ride and the number ofpassengers at a public transport station is strong. Stations with more parking spaces hadhigher ridership. This was not the case for stations located in a suburban environment, someeffect was indicated but the relationship was not as strong. The analysis of the two countiesdata showed unreasonably high passenger increases from P&R, indicating that some otherfactor also influences the result in this analysis.From the analysis of the temporal dataset the result showed that stations which adapted parkand ride did have a higher average passenger increase than the general trend within thetransport system. This indicates that park and ride do in fact increase public transportridership. / Den accelererande urbaniseringen har gjort behovet av att hantera miljöpåverkan ifråntransportsystemet större än någonsin och många beslutsfattare har valt att förordapendlarparkering (park and ride) som en metod för att minska biltrafik. Effekterna av attanvända denna planeringsmetod är dock inte fullt kända och eftersom pendlarparkeringar kanhamna i konflikt med andra planeringsmetoder som berör markanvändning så är det viktigtatt veta vilka effekter som kan förväntas av att införa pendlarparkeringar. Genom att vetavilka effekter som kan förväntas så blir möjligheterna bättre för beslutsfattare att tavälgrundade beslut och införa hållbara direktiv kopplade till stads och trafikplaneringen.Den här studien har utförts med data från två olika regioner för att ta reda på om effekterna avpendlarparkeringar skiljer sig beroende på vilken typ av miljö den är implementerad i.Dessutom har ytterligare en analys gjorts baserad på historiska data över resande, detta för attkunna mäta den direkta effekten av att införa eller expandera pendlarparkering på en hållplatsinom kollektivtrafiken.Resultatet visade att i glesbebyggda områden så var sambandet mellan antalet platser påpendlarparkeringar och antalet passagerare starkt. Statiner med fler pendlarparkeringsplatserhade fler resande än de med färre. Sambandet var inte lika starkt för stationer i förortsmiljö,ett visst samband kunde uppmätas men det var inte lika starkt. Analysen av de två regionernavisade dock på orealistiskt höga förhållanden mellan antalet pendlarparkeringsplatser ochantalet passagerare vilket indikerar att någon annan faktor också påverkar resultatet.Från analysen av historiska data över antal resande så visade resultatet att införandet avpendlarparkeringar ökar resandet med kollektivtrafiken i genomsnitt mer på de stationer därde införs jämfört med den generella trenden i kollektivtrafiksystemet. Detta indikerar attpendlarparkeringar har en positiv effekt på antalet resande med kollektivtrafiken.

This master thesis deals with the issues of snowboard teaching of children at older school age. The master thesis is divided into theoretical and practical part. The theoretical part describes the ride techniques and two fundamental but very different snowboard styles - freestyle and alpine. This part also presents the methodology of teaching and single elements of snowboarding methodical streak, that are acquired by motor learning. The motor abilities, skills and other factors that are related to snowboarding are explained here, too. Because this thesis is aimed at the snowboard teaching at elementary schools, the theoretical part is focused on integration of snowboarding into School Education Programme and on qualifications of teachers. The method of questioning used in the practical part tries to find out, if the snowboarding lessons for children at older school age are part of the school education in the region Tabor and what are the conditions of such an education. This part also deals with its technical and material provision. On winter training courses of one elementary school a research was done using the observational method and experiment. This research is aimed at snowboard teaching of pupils - beginners, who had different type and level of equipment and observes, how quickly are they...

Made available in DSpace on 2016-12-23T14:21:18Z (GMT). No. of bitstreams: 1 Andre Manhaes Machado.pdf: 1039285 bytes, checksum: 2b356c4d0279c975232bd92c5e2ab326 (MD5) Previous issue date: 2013-11-16 / O petróleo é a principal fonte energética do mundo contemporâneo, insumo básico de diversos setores econômicos. Com a descoberta do Pré-sal, o Brasil tem a oportunidade de tornar-se um dos maiores produtores de petróleo. Entretanto, para que isso seja alcançado, vários desafios deverão ser superados e, dentre eles, encontra-se o problema de transporte de empregados para operarem as plataformas offshore, distantes até 300km de distância da costa brasileira. Os problemas referentes ao deslocamento de empregados por meio de helicópteros são usualmente tratados como o Capacitated Helicopter Routing Problem (CHRP). Com base nas restrições de origem e de destino de cada cliente, no número de veículos e na capacidade e restrições de voo dos helicópteros, neste tipo de problema deseja-se minimizar os custos de aluguel de helicópteros mais o custo total de quilômetros voados. A presente dissertação propõe um modelo de Programação Linear Inteira Mista (PLIM) para o problema de roteirização de helicópteros com base no Dial-a-Ride Problem (DARP). Além do modelo apresentado, foram apresentados duas abordagens para a execução do modelo de forma exata: i) abordagem sem agrupamento, na qual as requisições que possuem origens iguais e destinos iguais são modeladas como requisições distintas e ii) abordagem com agrupamento, na qual requisições que possuem origens iguais e destinos iguais são aglutinados numa nova e única requisição. O modelo matemático foi executado no software CPLEX e os resultados mostraram que instâncias com até 25 requisições podem ser resolvidas pela abordagem com agrupamento / Oil is the main energy source of contemporary world; it is basic inputs of various economic sectors. With the discovery of Brazil pre-salt, there is an opportunity to become one of the largest oil producers. However, to achieve her own goals, Brazil must overcome several challenges, including the problem of transporting employees to operate offshore platforms 300km distant away from the Brazilian coast. Problems related to displacement of employees by helicopters are usually treated as Capacitated Helicopter Routing Problem (CHRP). Based on source and destination restrictions of each client, the number of vehicles, capacity and helicopter flight constraints, this type of problem proposes to minimize the cost of renting helicopters and the total cost of flown kilometers. This dissertation proposes a model of Mixed Integer Linear Programming (MILP) for the helicopters routing problem based on a Dial-a-Ride Problem (DARP). Besides the presented model, we presented two approaches to implementing the model in an exact way: i) non-clustered approach, in which requests that have the same origin and destination are equal modeled as separate requests; and ii) clustered approach, in which requests that have the same origins and destinations are clumped together in a new single request. The mathematical model was implemented in software CPLEX and results showed that instances with up to 25 requests can be resolved in the clustered approach

Problèmes de tournées de véhicules statiques et déterministes ne peuvent pas être utilisés dans de nombreux systémes de la vieréelle, du fait que les données d’entrée ne sont pas fiables et sont révélées au fil du temps. Dans cette thèse, nous étudions un problème de ramassage et de livraison avec fenêtres de temps et un maximum de temps de trajet - le problème dial-a-ride - dans sa variante statique et dynamique, et nous faisons des propositions spécifiques sur les modèles d’optimisation robustes pour résoudre ce problème. Pour résoudre le modèle statique, nous développons une approche branch-and-price qui gère toutes les contraintes detemps dans le processus de création d’itinéraires de véhicules. Notre travail est axé sur les techniques de résolution du sous-problème et d’accélération pour l’approche branch-and-price. Nos résultats numériques montrent que la méthode est compétitive par rapport aux approches existantes qui sont basées sur le branch-and-cut. Dans le contexte dynamique, où certaines données d’entrée sont révélées dynamiquement ou modifiées au fil du temps, nous appliquons notre algorithme branch-and-price pour la ré-optimisation dans une approche sur horizon glissant. / Static and deterministic vehicle routing problems cannot be used in many real-life systems, as input data are not reliable and revealedover time. In this thesis, we study a pickup and delivery problem with time windows accounting for maximum ride time constraints – the so-called diala- ride problem – in its static and dynamic variant, and we make specific proposal on robust optimization models for this problem. To solve the static model, we develop a branch-and-price approach that handles ride time constraints in the process of generating feasible vehicle routes in the course of the optimization procedure. Our work is focussed on the pricing problem solver and acceleration techniques for the branch-and-price approach. Our numerical results show that the method is competitive compared to existing approaches that are based on branch-and-cut. In the dynamic context, where some input data are revealed or modified over time, we apply our branchand- price algorithm for re-optimization in a rolling horizon approach.