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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.
121

[en] REQUIRED TANKER FLEET FOR OIL PRODUCTS DISTRIBUTION IN AN URBAN OPERATION IN BRAZIL / [pt] FROTA NECESSÁRIA A UMA OPERAÇÃO DE DISTRIBUIÇÃO DE DERIVADOS DE PETRÓLEO

ROGERIO DE GUSMAO PINTO LOPES 01 April 2004 (has links)
[pt] Esta dissertação apresenta um estudo sobre a Logística de Distribuição de Derivados de Petróleo, com o desenvolvimento de um modelo para a determinação do tamanho mínimo da frota rodoviária necessária a uma operação de distribuição. Esse modelo, implementado através de uma heurística, não se propõe a determinar o tamanho ótimo da frota e sim estabelecer um processo prático e racional, com base numa aplicação real e flexível. Antes da proposição da heurística, foi realizada uma revisão dos conceitos de supply chain management e comparado o desenvolvimento da indústria do petróleo no Brasil, frente a esses conceitos. A aplicação do modelo com dados reais teve seus resultados comparados com as formulações propostas por DAGANZO et al (1985) e NOVAES (1989). Essa comparação mostrou que a modelagem, desenvolvida para a solução do problema prático, chega a resultados adequados para o ajuste do tamanho da frota. A abordagem prática e a apresentação detalhada da estrutura do problema real são as principais contribuições que esse estudo agrega à área de conhecimento e pesquisa de logística de distribuição de derivados de petróleo. / [en] This master thesis presents a study of the logistics of oil products distribution. It also creates a model for the determination of minimum tankers fleet size, required for a distribution operation in Rio de Janeiro - Brazil. This model was implemented through heuristics, and doesn`t intend to determine the optimal fleet size; its objective instead is to establish a rational and a practical process for the distribution, based on flexible and real data application. Before the heuristics proposal, we took into consideration a review of supply chain management concepts and we evaluated these in relation to the development of the oil industry in Brazil. To validate the model`s correctness, the results of the heuristics run, using real data, were compared to figures obtained using DAGANZO et al (1985) and NOVAES (1989) formulation. This process shows that the developed model is able to solve practical problems regarding truck fleet size. The pragmatic approach and the detailed description of the real problem structure are the main contributions of this study to the field of logistics of oil products distribution.
122

[en] MINIMUM COST AND THE POINT OF SUBSTITUTION OF LOGISTICS EQUIPMENT: AN APPLICATION PROPOSAL TO THE FREIGHT TRANSPORTATION VEHICLES FLEET OF BRAZILIAN ARMY / [pt] CUSTO MÍNIMO E O PONTO DE SUBSTITUIÇÃO DE EQUIPAMENTOS LOGÍSTICOS: UMA PROPOSTA DE APLICAÇÃO À FROTA DE VEÍCULOS DE TRANSPORTE DE CARGAS DO EXÉRCITO BRASILEIRO

ELTON OLIVEIRA RODRIGUES 13 October 2004 (has links)
[pt] Esta dissertação apresenta um estudo sobre os custos que incidem sobre o transporte rodoviário de cargas e como estes determinam o melhor momento econômico para a substituição dos equipamentos de transporte. O problema é relevante para a organização militar, cujo principal objetivo é a execução da logística para o Exército. A modelagem matemática foi baseada na coleta de dados na organização militar e no Sistema Integrado de Administração Financeira do Governo Federal (SIAFI). O desenvolvimento do modelo que inclui equações matemáticas foi amparado pela bibliografia pesquisada e nos dados coletados no sistema federal SIAFI. Para a avaliação dos dados foram utilizadas planilhas eletrônicas do Microsoft Excel para se calcular apropriadamente os resultados. Os veículos considerados são utilizados em cinco grandes eixos de deslocamento dentro do território nacional. Estes veículos foram divididos em quatro categorias de acordo com o peso bruto total. Quando o modelo apresentou médio ou fraco grau de correlação múltipla (R2), outras funções matemáticas foram buscadas para melhorar o grau de correlação. Os resultados são mostrados de modo analítico e por meio de tabelas e gráficos com valores expressos em unidades monetárias em função do tempo de uso dos veículos. / [en] This dissertation presents a study about all the costs that fall upon the freight transportation in order to determine the best economic moment to replace transportation equipments. The problem is relevant to the military organization, whose main objective is the execution of logistics for the Army. The mathematical modeling was based on data collect in the military organization and in the Federal System Financial Administration (SIAFI). The development of the model wich includes mathematical equations was supported by bibliography research and data collected in the SIAFI federal system. For the evaluation of the data has used electronic spread sheets of Microsoft Excel was used for the calculation and the fitting of the results. The vehicles considered are used in five large axels of displacements along the national territory. These vehicles have been divided in four categories according to its total gross weight. When the model presented a medium or weak degree of multiple correlation (R2), others mathematical functions have been searched in order to improve the correlation degree. Results are shown in an analytical way and through tables and graphs wich express values in monetary terms as a time function of use of the vehicles.
123

Monetarização de gases poluentes de veículos do ciclo Otto no Brasil de 2000 a 2009

Gonçalves, Thais Souza 14 April 2015 (has links)
O agravamento de inúmeros problemas ambientais nas últimas décadas – contaminação do ar e da água, epidemias, secas prolongadas, enchentes, incêndios florestais, perdas da qualidade do solo, desastres nucleares e químicos, o crescimento do buraco na camada de ozônio e a atual escassez de água – têm emitido alertas a gestores e sociedade sobre a devida responsabilidade acerca dos recursos naturais. Nesse sentido, a valoração ou monetarização da emissão dos principais poluentes veiculares é fundamental para a formulação de políticas públicas ambientais, de gestão de transporte e trânsito que busquem resultados mais efetivos no controle das emissões. Esse trabalho apresenta uma breve discussão sobre as emissões veiculares de poluentes e as principais políticas públicas adotadas no setor e das emissões evitadas pelo uso do álcool carburante. Apresentou uma metodologia de cálculo baseada no quantitativo da frota de veículos, da intensidade de uso, dos fatores de emissão e dos valores monetários de referência de monóxido de carbono, óxido de nitrogênio, hidrocarbonetos e material particulado. Como resultado, apresenta-se as análises com seus respectivos valores das emissões referentes ao quantitativo monetário dos gases selecionados. Com o aumento do carro com tecnologia flex-fuel, observou-se a redução das emissões totais dos gases poluentes, embora a frota tenha aumentado em valores absolutos. Os valores monetários calculados por meio dos Indicadores de Monetarização de Emissões demonstraram que o monóxido de carbono é o principal responsável das emissões por automóveis que utilizam o ciclo Otto no Brasil, representando 45,7% das emissões e o valor monetário foi de R$ 4.736.386.753,28. Os hidrocarbonetos são o segundo gás mais emitido pela frota de automóveis, sendo responsável por 27,3% das emissões, e valor monetário de R$ 2.835.304.578,20. Em seguida surgem as emissões de óxido de nitrogênio, que em teve suas emissões reduzidas em 26,8% e foi responsável por R$ 2.785.548.815,02. Já as emissões de material particulado, em 2000 foram de R$ 705.307,57. Com a redução de 23%, foram responsáveis por R$ 545.752,13. Pode-se verificar, também, que o custo ambiental do período de 2000 a 2009, provocado pela frota de automóveis do ciclo Otto, dedicados ou de tecnologia flex-fuel, movidos à gasolina C e etanol hidratado, foi de R$ 10.363.277.869,40. / The worsening of numerous environmental problems in recent decades - contamination of air and water, epidemics, prolonged droughts, floods, forest fires, loss of soil quality, nuclear and chemical disasters, the hole growth in the ozone layer and the current shortage water - have issued alerts to managers and society on the proper responsibility about natural resources. In this sense, the valuation or monetization of emission of key vehicle pollutants is essential for the formulation of environmental policies, transportation management and traffic that seek more effective results in controlling emissions. This paper presents a brief discussion on vehicle emissions of pollutants and major public policies adopted in the industry and emissions avoided by the use of fuel ethanol. Presented a calculation method based on the amount of the vehicle fleet, the intensity of use, emission and monetary values of carbon monoxide reference factors, nitrogen oxides, hydrocarbons and particulate matter. As a result, the analysis is presented with the respective emission values for the quantitative currency of selected gases. With increasing car with flex-fuel technology, there was a reduction of total emissions of greenhouse gases, although the fleet has increased in absolute terms. The monetary values calculated using the emissions of monetization indicators showed that carbon monoxide is primarily responsible for emissions from motor vehicles the Otto cycle in Brazil, representing 45.7% of the emissions and the monetary value was R $ 4,736 .386.753,28. Hydrocarbons are the second most gas emitted by the car fleet, accounting for 27.3% of emissions, and monetary value of R $ 2,835,304,578.20. Then come the emissions of nitrogen oxide, which had its emission reductions of 26.8% and accounted for R $ 2,785,548,815.02. While emissions of particulate matter in 2000 were R $ 705,307.57. With the reduction of 23%, accounted for R $ 545,752.13. You can also check that the environmental cost for the period 2000-2009, caused by the fleet of vehicles of the Otto cycle, dedicated or flex-fuel technology, moved to C gasoline and hydrous ethanol was R $ 10,363,277,869 40.
124

Avaliação de impactos da inserção dos veículos elétricos nos sistemas de distribuição das concessionárias EDP Bandeirante e EDP ESCELSA. / Evaluation of the electric vehicles impact on the distribution systems of the EDP Bandeirante and EDP ESCELSA utilities.

João Paulo Niggli Silva 21 March 2014 (has links)
O objetivo deste trabalho é avaliar qual seria o impacto da inserção dos veículos elétricos nos sistemas de distribuição de energia elétrica de duas distribuidoras brasileiras, a EDP Bandeirante e EDP ESCELSA. Como esta tecnologia ainda não se encontra em utilização no Brasil, será adotada uma abordagem prospectiva, de modo a projetar o crescimento da frota de veículos elétricos até o ano de 2020. Para que se possa simular em uma sub estação, qual será o impacto da adoção desta tecnologia. Utilizando-se das projeções de crescimento da frota, também serão quantificados o impacto na matriz energética nacional e nas emissões de gases do efeito estufa. / This work, aims to evaluate the impact of the electric vehicles insertion on two power distribution utilities, EDP Bandeirante and EDP ESCELSA. How the electric vehicles aren´t a reality on Brazil, an prospective approach will be adopted, to project the growth of the electric vehicles fleet until the 2020 year, so that can be simulated in one substation, the impact that would be caused by the adoption of this technology. Using these projections, the impact on Brazilian energetic matrix, and the greenhouse gas emissions will be calculated to.
125

Métodos heurísticos aplicados ao problema de programação da frota de navios PLVs. / Heuristics methods applied in a PLV fleet scheduling problem.

Queiroz, Maciel Manoel de 03 October 2011 (has links)
O presente trabalho abordou um problema de programação de embarcações que realizam o lançamento de dutos ou linhas de produção e a interligação destes à infra-estrutura submarina, em uma operação de exploração de petróleo offshore. As tarefas são realizadas por embarcações PLVs (pipe layer vessels), e possuem como atributos: duração, em dias; lista de embarcações compatíveis; instante de liberação; penalidade relacionada ao atraso na execução da tarefa. Este problema é uma variação da classe de problemas de programação de máquinas paralelas não-relacionadas, em que o objetivo é minimizar o atraso ponderado total. Este trabalho empregou como métodos de solução a meta-heurística GRASP com path relinking. Esta técnica foi implementada utilizando os recursos de processamento multi-threading, de forma a explorar múltiplas trajetórias simultaneamente. Testes foram feitos para comprovar o desempenho das heurísticas propostas, comparando-as com limitantes fornecidos pelo método geração de colunas. / This work addressed a fleet scheduling problem present in the offshore oil industry. Among the special purpose services one will find the pipe layer activities and its connection to the subsea infrastructure, accomplished by the Pipe Layer Vessels (PLV). The jobs are characterized by a release date, which reflects the expected arrival date of the necessary material at the port. There are compatibility constraints between job and vessel, so that some vessels may not be able to perform a certain job; the duration of the jobs can be differentiated by vessel and if a job is finished after its due date, a penalty is incurred. This is a variation of the unrelated parallel machine problem with total weighted tardiness objective function. This research employed a metaheuristic GRASP with Path Relinking, which have proved to be competitive and an effective solution strategy. This method was implemented in a multi-threading scheme allowing multiple paths to be explored simultaneously. Computational experiments were conducted, comparing solutions with bounds provided by linear column generation.
126

Avaliação de impactos da inserção dos veículos elétricos nos sistemas de distribuição das concessionárias EDP Bandeirante e EDP ESCELSA. / Evaluation of the electric vehicles impact on the distribution systems of the EDP Bandeirante and EDP ESCELSA utilities.

Silva, João Paulo Niggli 21 March 2014 (has links)
O objetivo deste trabalho é avaliar qual seria o impacto da inserção dos veículos elétricos nos sistemas de distribuição de energia elétrica de duas distribuidoras brasileiras, a EDP Bandeirante e EDP ESCELSA. Como esta tecnologia ainda não se encontra em utilização no Brasil, será adotada uma abordagem prospectiva, de modo a projetar o crescimento da frota de veículos elétricos até o ano de 2020. Para que se possa simular em uma sub estação, qual será o impacto da adoção desta tecnologia. Utilizando-se das projeções de crescimento da frota, também serão quantificados o impacto na matriz energética nacional e nas emissões de gases do efeito estufa. / This work, aims to evaluate the impact of the electric vehicles insertion on two power distribution utilities, EDP Bandeirante and EDP ESCELSA. How the electric vehicles aren´t a reality on Brazil, an prospective approach will be adopted, to project the growth of the electric vehicles fleet until the 2020 year, so that can be simulated in one substation, the impact that would be caused by the adoption of this technology. Using these projections, the impact on Brazilian energetic matrix, and the greenhouse gas emissions will be calculated to.
127

Bestämning av optimal fordonspark -Distribution av bitumen vid Nynäs AB / A vehicle fleet sizing problem -distribution of bitumen at Nynas AB

Hjort, Mattias January 2005 (has links)
<p>Nynas produces bitumen at two refineries in Sweden. The bitumen is shipped to seven depots along the swedish coast line, and from the depots special trucks handle the transportation to customers. Recently Nynas has transformed its supply chain and closed down a few depots. At the moment the company is considering a further reduction of the number of depots. In connection to these discussions an analyse of the companys distributionsystem and of possible changes is required. In this thesis an optimization model is developed that simulates Nynas distribution of bitumen from the depots to the customers. The model is used to investigate the required vehicle fleet size for a number of different scenarios, that is with different depots closed down. The question to be answered is, thus, what depots could be closed without any dramatic increase in the required vehicle fleet size? Scenarios where customers are allocated an increased storage capacity are also studied. </p><p>The distribution model that is developed is an inventory route planning problem. It is solved by column generation. Each column represents a route and is generated by a subproblem with restrictions on permitted working hours for the truck drivers. Integer solutions are generated heuristically. </p><p>Simulations that have been performed with the model reveals interesting differences concerning how the distribution is handled in different parts of Sweden. In western Sweden the transportation planning works well, but the distribution in the central parts of the country could be planned in a better way. Results from simulations also show that the depots in Norrköping and Västerås could be closed down without increasing the vehicle fleet. Probably, the existing vehicle fleet size will be sufficient even with the Kalmar-depot closed down. Nevertheless, Nynas transportation suppliers will have to purchase new vehicles if the Sandarne-depot is to be closed. </p><p>Another interesting conclusion that can be drawn from this thesis is that there is a potential for reducing the vehicle fleet size if the storage capacity is increased at a few chosen customers. A considerably small increase in the storage capacity at a few big customers that are located far from the depots will have a great effect.</p>
128

Bestämning av optimal fordonspark -Distribution av bitumen vid Nynäs AB / A vehicle fleet sizing problem -distribution of bitumen at Nynas AB

Hjort, Mattias January 2005 (has links)
Nynas produces bitumen at two refineries in Sweden. The bitumen is shipped to seven depots along the swedish coast line, and from the depots special trucks handle the transportation to customers. Recently Nynas has transformed its supply chain and closed down a few depots. At the moment the company is considering a further reduction of the number of depots. In connection to these discussions an analyse of the companys distributionsystem and of possible changes is required. In this thesis an optimization model is developed that simulates Nynas distribution of bitumen from the depots to the customers. The model is used to investigate the required vehicle fleet size for a number of different scenarios, that is with different depots closed down. The question to be answered is, thus, what depots could be closed without any dramatic increase in the required vehicle fleet size? Scenarios where customers are allocated an increased storage capacity are also studied. The distribution model that is developed is an inventory route planning problem. It is solved by column generation. Each column represents a route and is generated by a subproblem with restrictions on permitted working hours for the truck drivers. Integer solutions are generated heuristically. Simulations that have been performed with the model reveals interesting differences concerning how the distribution is handled in different parts of Sweden. In western Sweden the transportation planning works well, but the distribution in the central parts of the country could be planned in a better way. Results from simulations also show that the depots in Norrköping and Västerås could be closed down without increasing the vehicle fleet. Probably, the existing vehicle fleet size will be sufficient even with the Kalmar-depot closed down. Nevertheless, Nynas transportation suppliers will have to purchase new vehicles if the Sandarne-depot is to be closed. Another interesting conclusion that can be drawn from this thesis is that there is a potential for reducing the vehicle fleet size if the storage capacity is increased at a few chosen customers. A considerably small increase in the storage capacity at a few big customers that are located far from the depots will have a great effect.
129

Analysis of a Clean Energy Hub Interfaced with a Fleet of Plug-in Fuel Cell Vehicles

Syed, Faraz January 2011 (has links)
The ‘hydrogen economy’ represents an energy system in which hydrogen and electricity are the dominant energy carriers for use in transportation applications. The ‘hydrogen economy’ minimizes the use of fossil fuels in order to lower the environmental impact of energy use associated with urban air pollution and climate change. An integrated energy system is required to deal with diverse and distributed energy generation technologies such a wind and solar which require energy storage to level energy availability and demand. A distributed ‘energy hub’ is considered a viable concept in envisioning the structure of an integrated energy system. An energy hub is a system which consists of energy input/output, conversion and storage technologies for multiple energy carriers, and would provide an interface between energy producers, consumers, and the transportation infrastructure. Considered in a decentralized network, these hubs would form the nodes of an integrated energy system or network. In this work, a model of a clean energy hub comprising of wind turbines, electrolyzers, hydrogen storage, a commercial building, and a fleet of plug-in fuel cell vehicles (PFCVs) was developed in MATLAB, with electricity and hydrogen used as the energy carriers. This model represents a hypothetical commercial facility which is powered by a renewable energy source and utilizes a zero-emissions fleet of light duty vehicles. The models developed herein capture the energy and cost interactions between the various energy components, and also calculate the CO2 emissions avoided through the implementation of hydrogen economy principles. Wherever possible, similar models were used to inform the development of the clean energy hub model. The purpose of the modelling was to investigate the interactions between a single energy hub and novel components such as a plug-in fuel cell vehicle fleet (PFCV). The final model reports four key results: price of hub electricity, price of hub hydrogen, total annual costs and CO2 emissions avoided. Three scenarios were analysed: minimizing price of hub electricity, minimizing total annual costs, and maximizing the CO2 emissions avoided. Since the clean energy hub could feasibly represent both a facility located within an urban area as well as a remote facility, two separate analyses were also conducted: an on-grid analysis (if the energy hub is close to transmission lines), and an off-grid analysis (representing the remote scenarios). The connection of the energy hub to the broader electricity grid was the most significant factor affecting the results collected. Grid electricity was found to be generally cheaper than electricity produced by wind turbines, and scenarios for minimizing costs heavily favoured the use grid electricity. However, wind turbines were found to avoid CO2 emissions over the use of grid electricity, and scenarios for maximizing emissions avoided heavily favoured wind turbine electricity. In one case, removing the grid connection resulted in the price of electricity from the energy hub increasing from $82/MWh to $300/MWh. The mean travel distance of the fleet was another important factor affecting the cost modelling of the energy hub. The hub’s performance was simulated over a range of mean travel distances (20km to 100km), and the results varied greatly within the range. This is because the mean travel distance directly affects the quantities of electricity and hydrogen consumed by the fleet, a large consumer of energy within the hub. Other factors, such as the output of the wind turbines, or the consumption of the commercial building, are largely fixed. A key sensitivity was discovered within this range; the results were ‘better’ (lower costs and higher emissions avoided) when the mean travel distance exceeded the electric travel range of the fleet. This effect was more noticeable in the on-grid analysis. This sensitivity is due to the underutilization of the hydrogen systems within the hub at lower mean travel distances. It was found that the greater the mean travel distance, the greater the utilization of the electrolyzers and storage tanks lowering the associated per km capital cost of these components. At lower mean travel distances the utilization of the electrolyzers ranged from 25% to 30%, whereas at higher mean travel distances it ranged from 97% to 99%. At higher utilization factors the price of hydrogen is reduced, since the cost recovery is spread over a larger quantity of hydrogen.
130

Planning Robust Freight Transportation Operations

Morales, Juan Carlos 20 November 2006 (has links)
This research focuses on fleet management in freight transportation systems. Effective management requires effective planning and control decisions. Plans are often generated using estimates of how the system will evolve in the future; during execution, control decisions need to be made to account for differences between actual realizations and estimates. The benefits of minimum cost plans can be negated by performing costly adjustments during the operational phase. A planning approach that permits effective control during execution is proposed in this dissertation. This approach is inspired by recent work in robust optimization, and is applied to (i) dynamic asset management and (ii) vehicle routing problems. In practice, the fleet management planning is usually decomposed in two parts; the problem of repositioning empty, and the problem of allocating units to customer demands. An alternative integrated dynamic model for asset management problems is proposed. A computational study provides evidence that operating costs and fleet sizes may be significantly reduced with the integrated approach. However, results also illustrate that not considering inherent demand uncertainty generates fragile plans with potential costly control decisions. A planning approach for the empty repositioning problem is proposed that incorporates demand and supply uncertainty using interval around nominal forecasted parameters. The intervals define the uncertainty space for which buffers need to be built into the plan in order to make it a robust plan. Computational evidence suggests that this approach is tractable. The traditional approach to address the Vehicle Routing Problem with Stochastic Demands (VRPSD) is through cost expectation minimization. Although this approach is useful for building routes with low expected cost, it does not directly consider the maximum potential cost that a vehicle might incur when traversing the tour. Our approach aims at minimizing the maximum cost. Computational experiments show that our robust optimization approach generates solutions with expected costs that compare favorably to those obtained with the traditional approach, but also that perform better in worst-case scenarios. We also show how the techniques developed for this problem can be used to address the VRPSD with duration constraints.

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