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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

The future of Remote Operations for Autonomous Vehicles : Exploring Human-Automation Teamwork and Situational Awareness for SAE Level 4 trucks

Klingberg, Linnea January 2023 (has links)
The level of autonomation and the number situations which an autonomous vehicle can handle continuously increases. However, even fully autonomous vehicles will need human support, especially when system failures occur. Remote operations enables vehicles to operate autonomously when possible and keeps the human in the loop to assist when needed by allocating them to a remote operating center (ROC). It is a new field within autonomous trucks and little research has thus been conducted on the topic. By taking an approach from the fields of aviation and maritime, where remote operations has been researched for longer, the study aims to transfer knowledge to road freight and to enable remote operations at a management mode. The focus of the study is thus to investigate which information is important for the remote operator (RO) when manual procedures are automated, and to define recommendations for how a ROC could be designed from a human-automation teamwork and situational awareness perspective. The results of the conducted interviews find that the RO first and foremost needs information regarding failures of the automation, including how the failures could be solved. However, it also confirms previous research emphasizing interactive interfaces to avoid passive monitoring, as that is likely to cause an out-of-the-loop problem. Furthermore, recommendations which could be defined regarding the design of a ROC include incorporating both verbal and digital communicational abilities, and the possibility to collaborate, both internally and externally. Lastly, the results show an importance to differentiate between different modes of remote operations in the ROC to remain clear of the responsible actor and avoiding automation surprise.
152

An Exploration and Demonstration of System Modeling for Profitable Urban Air Mobility Operations Using Simulation and Optimization

Brandon E Sells (16807035) 09 August 2023 (has links)
<p>The research effort addressed important gaps in the modeling to simulate Urban Air Mobility (UAM) operations and couple optimization analyses for vehicle design, fleet allocations, and operational choices for next generation urban travel. Urban Air Mobility is expected to be a \$1 trillion dollar industry by 2040, but operators and designers have limited models and tools to estimate fleet performance, cost metrics, emissions performance, and profit for a given concept under future concepts of operations. A review of the literature reveals 14 modeling gaps related to infrastructure, operations, airspace, vehicles, and customers. In addition, the UAM industry requires better understanding of how operational choices may impact vehicle design and fleet allocations in a market with significant economic barriers and infrastructure needs. To address those needs, this effort proposed alternatives to address modeling challenges and develop studies to evaluate UAM vehicle concepts and concepts of operations in ways once not possible using the enhanced modeling tools. The research findings revealed that modeling coupled design/fleet and operational choices can affect daily profitability potential by 2-4\times\, for piloted and autonomous operations and affect the fleet size from between 12-50 vehicles across small, medium, and large metropolitan areas. The modeling capability provided by the improvements in UAM operations simulations and accessing vehicle and fleet metrics enables future studies to address UAM in a holistic manner. The increased capability could benefit the UAM community and inform future operations and concepts of operations in preparation for ubiquitous operations.</p>
153

En fossilfri fordonsflotta inom Polismyndigheten : En realistisk framtid eller en utopi?

Mårtensson, Elvira January 2022 (has links)
För att nå internationella såväl som nationella miljömål står samhället inför en omfattande omställning av fordonsflottan. Utfasningsutredningen (2021) redogör i sin rapport för hur samtliga aktörer i samhället behöver vidta åtgärder för att bidra till måluppfyllnad. En central aktör som i dagsläget vidtar åtgärder är fordonstillverkare som med ett varierande tidsspann har förmedlat ambitionen om att enbart producera fordon med nollnettoutsläpp inom spannet 2030 – 2035. Fordonstillverkarnas omställning kommer att få konsekvenser för andra samhälleliga aktörer som är beroende av en tillförlitlig fordonsflotta i syfte att genomföra sitt uppdrag, en av dessa aktörer är polismyndigheten. Syftet med denna uppsats är att kartlägga vilka främjande samt hindrande faktorer som finns för implementering av en fossilfri fordonsflotta i dagsläget. Ett särskilt fokus kommer i uppsatsen att vara polisregion Nord som med sina geografiska förutsättningar upptar 55% av Sveriges yta, samtidigt som 26 av Sveriges 30 mest glesbefolkade kommuner återfinns inom regionen. För att kartlägga förutsättningarna ska uppsatsen utifrån implementeringsteoretiska utgångspunkterna förstå, vilja och kunna studera dokument och genomföra intervjuer med relevanta aktörer från nationell, regional samt polisområdesnivå. I dagsläget framgår det av kartläggningen att en fossilfri fordonsflotta inom polismyndigheten snarare är en utopi än en realistisk framtid. Ingen av de valda teoretiska utgångspunkterna förstå, vilja och kunna kan i dagsläget betraktas som helt uppfyllda. I de fall åtgärder inte vidtas kan myndighetens operativa förmåga komma att bli begränsad, vilket kommer särskilt hårt mot polisregion Nord och dess invånare. / To achieve international as well as national environmental targets, society is facing a major shift in the vehicle fleet. Utfasningsutredningen (2021) sets out how all actors in society need to take action to contribute to meet the targets. A key actor currently taking action is vehicle manufacturers. With varying timeframes, several manufacturers have communicated the ambition to produce only vehicles with zero net emissions within the range 2030 - 2035. The transition of vehicle manufacturers will have implications for other societal actors that depend on a reliable vehicle fleet to carry out their mission, one of these actors being the police authorities. The aim of this paper is to identify the facilitators and barriers to the implementation of a fossil-free vehicle fleet in the present time. A special focus will be the police region North which with its geographical conditions occupies 55% of Sweden's surface, where 26 of Sweden's 30 most sparsely populated municipalities are found in the region. To map the conditions, the paper will study documents and conduct interviews with relevant actors from national, regional and police area level based on implementation theory regarding the concepts understanding, will and being able to. At present, the thesis shows that a fossil-free vehicle fleet in the police authority is more of a utopia than a realistic future. None of the implementation theoretical starting points can be considered as fully met at present. If no action is taken, the operational capability of the authority may be limited, which will have a particular impact on the Northern police region and its inhabitants.
154

Regression Model to Project and Mitigate Vehicular Emissions in Cochabamba, Bolivia

Wagner, Christopher 28 August 2017 (has links)
No description available.
155

Laddning av framtiden : Hinder och drivkrafter för adoptionen av elbilar / Charging the future : Obstacles and possibilities towards the adoption of the electric vehicle

Lövgren, Johan, Ulmgren, Måns January 2020 (has links)
Personbilsflottan står för en stor andel av de globala CO2-utsläppen och genom vidare implementering av alternativa drivmedel kan transportsektorn i framtiden bli mer hållbar. Tekniken kring elbilar vad gäller bland annat batteriets kapacitet och bilens prestanda har under de senaste decenniet gjort stora framsteg där elbilen idag är direkt konkurrerande med en bil driven på fossila bränslen i många avseenden. Denna rapport kartlägger de drivande faktorer och hinder som elektrifieringen av personbilsflottan står inför utifrån tre perspektiv; elbilens batteri, laddningsinfrastrukturen och politiska styrmedel. Metoden för arbetet har varit en litteraturstudie samt en enkätstudie där resultatsammanställningen av varje perspektiv underströk vilka de kritiska faktorerna är. Vad gäller elbilsbatteriet visar resultaten att prisutvecklingen tillsammans med den tekniska utvecklingen av batterierna är en stor drivande kraft. Däremot är den begränsade körsträckan och batteriets känslighet vad gäller degradering av batterihälsa ett hinder. Fortsättningsvis visar resultaten att laddning som till stor andel kommer ske i hemmet är en stor drivande kraft som minimerar vikten av de hinder som består i höga investeringskostnader och påfrestningar på elnätet. Enkätstudiens resultat visar att individer ej uppfattar elbilens kortare körsträcka eller laddning som ett problem i lika stor utsträckning som litteraturstudien föreslog. Det framgick att en stor drivande kraft är politiska styrmedel då resultatet stödjer att en klar majoritet av enkätdeltagarna skulle köpt en elbil om köpkostnaden hade varit densamma som för en bensin-/dieseldriven bil. En diskussion om omställningen till el i utsläppstunga industrier inklusive transportsektorn visar att störst förändring kan ske i länder så som Sverige, Finland och Island där ländernas elmix till stor andel utgörs av renproducerad el. Avslutningsvis konstateras det att synergieffekter av utvecklingen bör tas till vara på och applicerar i andra industrier där en utökad elektrifiering är möjlig. / The passenger car fleet accounts for a large proportion of global CO2 emissions and through further implementation of alternative fuels, the transport sector can become more sustainable in the future. The technology of electric cars in terms of performance and battery capacity has, in the last decade, made great progress where the electric car today is directly competing with a car driven on fossil fuels in many respects. This report identifies the driving factors and obstacles that the electrification of the passenger car fleet faces from three perspectives; electric car battery, charging infrastructure and political instruments. The method for the work has been a literature study as well as a survey study where the results compilation of each perspective emphasized what the critical factors are. With regard to the electric car battery, the results show that the price trend together with the technical development of the batteries is a major driving force. However, the limited mileage and the sensitivity of the battery to degradation of battery health is an obstacle. Continuing, the results show that charging, which to a large extent will take place in the home, is a major driving force that minimizes the weight of the obstacles that consist in high investment costs and stress on the electricity grid. The results of the survey show that individuals do not perceive the shorter driving distance or charge of the electric car as a problem to the same extent as the literature study suggested. It turned out that a major driving force is political instruments as the result supports that a clear majority of the survey participants would have bought an electric car if the purchase cost had been the same as for a gasoline / diesel driven car. A discussion of the transition to electricity in emission-heavy industries, including the transport sector, shows that the greatest change can take place in countries such as Sweden, Finland and Iceland, where the countries' electricity mix is ​​largely made up of clean electricity. Finally, it is stated that synergy effects of the development should be exploited and applied in other industries where increased electrification is possible.
156

Description and Evaluation of a Novel Approach for Offline Coordination of Routing Autonomous Free-Ranging Vehicles in Intralogistics Transportation Systems

Reith, Karl-Benedikt 03 May 2024 (has links)
Driven by recent technical advances, vehicle-based transportation systems in intralogistics are currently shifting from automated guided vehicles (AGVs) to autonomous mobile robots (AMRs). Unlike AGVs, AMRs are not bound to a physical or virtual track and autonomously determine their movements. While the increase in freedom for routing leads to improvements in terms of system flexibility and scalability, it also poses new challenges in terms of coordination and thus the high-performance routing behavior of an entire fleet. Accepted and widely used algorithms in the AGV field are often barely applicable to large fleets of free-ranging AMRs, while typical algorithms from the field of mobile robotics usually focus on different objectives. This thesis presents a novel concept for determining global routes, the so-called lanemap, that enables the synchronized movements of multiple free-ranging vehicles in arbitrary layouts without increasing calculation effort during online operations. The basic idea consists in creating a lanemap offline that provides the AMRs with a set of suggested global lanes from various starting positions to different destinations. On the one hand, the application of a lanemap lowers each AMRs’ individual degree of freedom. However, coordinating lanes sensibly beforehand enables short travel distances as well as a low probability of routing conflicts, which improves the performance of the entire AMR fleet on the other hand. Since the lanemap only provides an offline calculated global route as suggestion, the concept can be combined with any established online approach, such as a local conflict avoidance/resolution approach, or with in-depth coordination of all vehicle movements. This thesis presents a theoretical mathematical model and a practically applicable heuristic approach for the creation of a lanemap. As proof of concept, simulation experiments show that the heuristic is generally capable of creating lanemaps for all different kinds of layouts. Furthermore, the concept allows for the determination of customized routes for a specific fleet size and an anticipated transportation demand. Therefore, once system requirements are known, a beneficial set of lanemaps for typical constellations can be calculated in advance and integrated into routing as needed.
157

Domestic sources of Ukraine's foreign policy : examining key cases of policy towards Russia, 1991-2009

Kravets, Nadiya January 2012 (has links)
Ukraine’s foreign policy has puzzled observers since the dissolution of the Soviet Union due to its unusual inconsistency. This inconsistency exhibited itself in contradictory decisions by the Ukrainian executive carried out within a short period of time, which signalled either greater cooperation with Russia and relative cooling of relations with the West, or integration into Western institutions and worsening of the relations with Moscow. This study aims to explain the inconsistency by examining the sources of Ukraine’s foreign policy through process-tracing in four policy cases: Ukraine’s renouncement of nuclear weapons (1991-1994), the status of the Black Sea Fleet (1991-1997), the Odesa-Brody pipeline (2002-2004), and the 2006-2009 gas disputes. Contrary to dominant interpretations of Ukraine’s foreign policy vacillation that emphasise the role of external influences, especially that of Russia and the West, this study concludes that Ukraine’s inconsistent foreign policy decisions are best explained by domestic factors – intra-executive divisions and the influence of vested interests on policy-making. The work relies on the use of primary sources including archival research, elite interviews, and Ukrainian and Russian newspaper reports.
158

Análise e dimensionamento de frota de caminhões em circuito fechado para fornecimento de madeira. / Analysis and truck fleet sizing in closed circuit for wood supply.

Silva, Natasha Roberta Galvão da 07 July 2015 (has links)
A racionalização no uso dos recursos sempre foi uma preocupação dos gestores de empresas e com a crescente competitividade entre essas organizações, faz-se necessário, portanto, um controle minucioso dos custos. Empresas do ramo florestal lidam todos os dias com problemas desde o nível estratégico, como a decisão de em quais regiões realizarem o plantio das árvores, até o nível operacional, que tem maior impacto sobre as operações diárias e que envolve as decisões de transporte de madeira. Nesse sentido, o investimento em ferramentas que garantam maior eficiência do transporte diário de madeira é considerado como ponto de partida para que essas organizações possam sustentar sua competitividade no mercado. Dessa forma, esta dissertação tem como objetivo dimensionar, através de um modelo de simulação, a frota de caminhões utilizada para o transporte diário de madeira em uma indústria de papel e celulose, com vistas a permitir um fluxo coordenado e constante de matéria prima, comparando o sistema atual com um sistema baseado em uma nova lógica de despacho de caminhões aplicada ao simulador. O modelo de simulação desenvolvido foi construído através do software ARENA® e conta com uma interface de dados construída com o auxílio do Microsoft Excel®, na qual são inseridos, de maneira estruturada, os dados de entrada necessários. Com este modelo, pretende-se auxiliar na solução de um problema operacional de transporte de madeira, uma vez que é possível determinar, em um horizonte de planejamento previamente definido, o tamanho da frota capaz de atender a uma demanda programada, permitindo maior eficiência ao sistema e redução de desperdícios. / The rational use of resources has always been a concern of business managers and the growing competition between companies requires a complex control of costs. Companies in the forestry sector deal with everyday problems from the strategic level, the decision on which regions make the planting of trees, to the operational level, which has a greater impact on the daily operations and decisions involving timber transport. Accordingly, investment in tools that ensure higher efficiency of daily transportation of wood is considered as the starting point for these organizations to sustain their competitiveness in the market. Thus, this thesis is designed to measure, through a simulation model, the fleet of trucks used for daily transportation of wood into a pulp and paper industry, with a view to providing coordinated and constant flow of raw material. The developed simulation model was built by ARENA ® software and has a data interface built with the help of Microsoft ® Excel, in which the input data required are inserted. With this model, we intend to assist in the solution of an operating problem of timber transport, since it is possible to determine the fleet size able to attend a scheduled demand, allowing the system more efficient and reduce waste, in a planning horizon previously defined.
159

Modelagem para operação de Bus Rapid Transit. / Operation modeling for bus rapid transit.

Gorni, Daniel 24 November 2010 (has links)
Este trabalho é um modelo para controle de operação de frota de ônibus público urbano de baixa demanda, que objetiva o monitoramento (e intervenção, quando necessário), de forma que os ônibus monitorados cumpram a programação predeterminada pela grade-horária, evitando assim situações indesejáveis como atrasos ou congestionamentos nas estações de embarque e desembarque. A gestão do controle da movimentação dos ônibus se baseia em intervenções a serem realizadas na frota, considerando-se o sistema Bus Rapid Transit, que possui como grande diferencial as faixas segregadas para circulação dos ônibus. O objetivo é propor intervenções na frota (ações enviadas diretamente ao motorista como, por exemplo, diminuir a velocidade), e analisar os resultados, de forma a contribuir para diminuir dois grandes problemas em transporte público urbano: (1) o não cumprimento dos horários e (2) congestionamentos nas estações. Esses dois problemas geram reações em cadeia que acabam também afetando a regularidade de outros ônibus que compartilhar a mesma via e estações. Instituições públicas ou privadas de ônibus urbano podem obter benefícios utilizando um bom sistema de monitoramento e controle de frota, como por exemplo: mais segurança e previsibilidade nos horários, melhor adequação entre demanda e oferta do serviço, gerenciamento da frota através dos relatórios de pontualidade e desvio, dentre outros. Além disso, a melhora da qualidade do serviço traz como conseqüência o aumento no número de usuários do transporte, devido à oferta de um sistema mais atrativo, seguro e eficiente. A metodologia apresentada neste trabalho é constituída de um modelo para monitoramento da operação da frota e detecção de inconformidades dos ônibus, baseado na grade-horária e em um algoritmo de tomada de decisão, que objetiva a correção das inconformidades identificadas. Na tentativa de resolver (ou diminuir) os problemas que possam surgir durante a circulação dos ônibus, algoritmos (heurísticos) de decisão são utilizados em simulações de situações adversas. Com essas simulações é possível efetuar comparação das situações sem e com as intervenções propostas pelo algoritmo de decisão. Um sistema de informação geográfica é utilizado para manipulação dos dados e apresentação dos mesmos. De forma unifilar, é possível comparar as situações com e sem intervenções. Gráficos e tabelas complementam a apresentação dos resultados, onde é possível identificar e perceber a vantagem no monitoramento e intervenção na frota (a fidelidade à grade-horária melhora com as situações/intervenções simuladas). / This dissertation is a model for management of urban public bus fleet operation control, aimed at monitoring (and intervention when necessary) so that the buses monitored meet the pre-determined schedule by the time-grid, thus avoiding undesirable situations such as delays or congestion in the stations of embarkation and disembarkation. The proposed operational management model and the interventions to be carried out in the fleet are possible considering the Bus Rapid Transit system that has segregated roads for the movement of buses. The goal is to propose interventions in the fleet (actions will be sent directly to the driver, like - change the bus velocity), and analyze the results in order to help reduce two major problems in urban public transport: (1) non compliance with the schedules and (2) congestion at stations. These two problems create chain reactions that end up affecting the regularity of other vehicles who share the same track and stations. Public or private urban bus institutes can benefit by using a good system of monitoring and control of the fleet, for example: more security and predictability in schedules, better match between demand and supply of the service, fleet management through the reports of punctuality and deviation, among others. Moreover, the improvement of service quality has as consequence the increase in the number of users of transport, due to availability of a more attractive, safe and efficient bus service. The methodology presented here consists of a model for fleet tracking (operation control) and tracing of unconformities buses based on time-grid and on an algorithm of decision-making that aims to correct non-conformities identified. In an attempt to solve (or reduce) the problems that may arise during the movement of buses, algorithms (heuristic) decision is used in simulations of adverse situations. In these simulations can be performed comparing the situations \"without\" and \"with\" the interventions proposed by the decision algorithm. A geographic information system is used for data manipulation and presentation of them. Using linear representation is possible to compare the buses situations with and without interventions. Charts and tables complement the presentation of results, where it is possible to identify and realize the advantage in monitoring and intervention in the fleet (fidelity to the time-grid improvement with the simulated situations/interventions).
160

Admiral Thomas C. Hart And The Demise Of The Asiatic Fleet 1941 – 1942

DuBois, David 01 May 2014 (has links)
Admiral Thomas C. Hart And The Demise Of The Asiatic Fleet 1941 – 1942 is a chronicle of the opening days of World War II in the Pacific and the demise of the U.S. Navy’s Asiatic Fleet. Beginning with the background of Four Star Admiral Thomas Hart, this chronicle shows the history of the nearly obsolete ships that fought in the beginning of World War II. The reader will come to realize how and why this fleet ceased to exist within ninety days from the start of the war. Historical evidence will show that the damage inflicted on the Japanese was much greater than what was recorded in popular history. Hart was relieved of his command due to political considerations but not a single ship was lost while he was in command of the Asiatic Fleet. Hart fulfilled his orders to preserve the integrity and safety of the American Asiatic Fleet.

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