• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 601
  • 452
  • 344
  • 109
  • 72
  • 52
  • 25
  • 23
  • 22
  • 18
  • 18
  • 13
  • 11
  • 9
  • 7
  • Tagged with
  • 2057
  • 324
  • 280
  • 273
  • 255
  • 230
  • 213
  • 184
  • 174
  • 167
  • 160
  • 159
  • 126
  • 120
  • 109
  • 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.
251

MIKROREGION SDRUŽENÍ RŮŽE / MICROREGION SDRUŽENÍ RŮŽE

KARPYTOVÁ, Gabriela January 2010 (has links)
This diploma paper is focused on financing issues in microregion Sdružení Růže connected with national and European funds. The paper is divided into two parts - first, theoretical, embracing particularly profiles of selected subsidies and introduction to rural development. The second, practical part, contains SWOT analysis of microregion Sdružení Růže featuring weaknesses and risks restraining the successful development. Furthermore, practical part presents research data of subsidies utilization until the year 2009. Several possibilities of additional funding results from this output.
252

Scatter Search para problemas de roterização de veículos com frota heterogênea, janelas de tempo e entregas fracionadas. / Scatter search for Heterogeneous Fleet vehicle routing problem with Time Windows and Split Deliveries.

Patrícia Prado Belfiore 03 March 2006 (has links)
Esta tese estuda a implementação de heurísticas e da metaheurística scatter search (SS) em um problema de roteirização de veículos com frota heterogênea, janelas de tempo e entregas fracionadas (Heterogeneous Fleet Vehicle Routing Problem with Time Windows and Split Deliveries – HFVRPTWSD). O HFVRPTWSD é uma combinação do problema de roteirização com frota heterogênea (HFVRP), problema de roteirização de veículos com janelas de tempo (VRPTW) e problema de roteirização com entregas fracionadas (VRPSD). O problema é baseado em um único depósito, a demanda dos clientes pode ser maior que a capacidade dos veículos e, além das restrições de janelas de tempo, há também restrições de capacidade dos veículos e restrições quanto ao tipo de veículo. O VRPSD foi introduzido na literatura por Dror e Trudeau em 1989. No problema de roteirização de veículos com entregas fracionadas, cada cliente pode ser abastecido por mais de um veículo, enquanto no problema clássico de roteirização de veículos (VRP), cada cliente é atendido por um único veículo. Desta forma, para o VRPSD, além dos roteiros de entrega, deve-se determinar a quantidade entregue a cada cliente em cada veículo. Todos os problemas de roteirização com entregas fracionadas encontrados na literatura (VRPSD e suas extensões) têm como característica frota homogênea. O problema estudado neste trabalho difere, portanto, de todos os problemas de roteirização com entregas fracionadas da literatura, pois tem, como característica, frota heterogênea. O mesmo raciocínio vale para problemas de roteirização de veículos com frota heterogênea. Os modelos são aplicados em uma rede de varejo no Brasil que é abastecida a partir de um centro de distribuição. A rede compõe um total de 519 lojas distribuídas em 12 estados do país. As heurísticas e a metaheurística scatter search também são aplicadas em três conjuntos de problemas encontrados na literatura (SOLOMON, 1987; HO E HAUGLAND, 2004; LIU E SHEN, 1999), com o objetivo de avaliar o desempenho dos algoritmos para cada problema. O problema consiste em determinar, a cada dia, como alocar os caminhões às lojas, a quantidade de carga em cada caminhão a ser entregue em cada uma das lojas, qual o melhor roteiro e o tempo de início de atendimento do primeiro cliente da rota, de forma a minimizar o custo total de distribuição, garantindo que a demanda das lojas seja atendida e as demais restrições do problema sejam respeitadas. Para a resolução do VRPSD e suas extensões, a única metaheurística encontrada na literatura foi busca tabu. Para o problema de roteirização com frota heterogênea e suas extensões, foram implementadas apenas as metaheurísticas busca tabu e BATA (Back-Tracking Adaptative Threshold Accepting). As estratégias de solução propostas no presente trabalho consistem na implementação de heurísticas construtivas e da metaheurística scatter search. As soluções iniciais de SS são obtidas através da implementação de quatro heurísticas construtivas: heurística de economias, heurística de inserção seqüencial baseada nas idéias de Solomon (1987), heurística de inserção seqüencial baseada nas idéias de Ho e Haugland (2004) e adaptação da heurística de inserção seqüencial de Dullaert et al. (2002). Para o caso real, foi possível uma redução no custo total da frota comparado com a solução atual da empresa. Para algumas instâncias dos três conjuntos de problemas da literatura, os algoritmos apresentaram resultados similares ou superiores às melhores soluções encontradas. / This thesis studies the implementation of heuristics and scatter search (SS) metaheuristic in a Heterogeneous Fleet Vehicle Routing Problem with Time Windows and Split Deliveries (HFVRPTWSD). The HFVRPTWSD is a combination of Heterogeneous Fleet Vehicle Routing Problem (HFVRP), Vehicle Routing Problem with Time Windows (VRPTW) and Vehicle Routing Problem with Split Deliveries (VRPSD). The problem is based in a single depot, the demand of each client can be greater than the vehicle’s capacity and beyond the time windows constraints, and there are also constraints on the vehicle capacity and vehicles type. The VRPSD was introduced in the literature by Dror e Trudeau in 1989. In the split deliveries vehicle routing problem, each client can be supplied by more than one vehicle; while in a classic vehicle routing problem (VRP) each client is supplied by only one vehicle. Thus, for the VRPSD, besides the delivery routes, the amount to be delivered to each client in each vehicle must also be determined. All the split delivery vehicle routing problems researched in the literature (VRPSD and its extensions) have as a characteristic the homogeneous fleet. Therefore, the problem studied differs from the split deliveries vehicle routing problems of the literature because it has a heterogeneous fleet. The same reasoning can be applied in heterogeneous fleet vehicle routing problem. The models will be applied in a retail market in Brazil that is supplied by a distribution center. The market has 519 stores distributed in 12 Brazilian states. The heuristics and the scatter search metaheuristic will also be applied in three benchmark problems (SOLOMON, 1987; HO AND HAUGLAND, 2004; LIU AND SHEN, 1999), aiming to evaluate the design of the algorithms for each problem. The problem consists in determining, each day, how to allocate the trucks to the stores, the amount to be delivered in each truck to each client, which one is the best route and the initial time for attending the first client, with the aim of minimizing the total distribution cost, attending the clients’ demand and respecting all the problem’s constraints. For the VRPSD and its extensions, the only metaheuristic implemented in the literature was tabu search. For the heterogeneous fleet vehicle routing problem and its extensions, only the tabu search and BATA (Back-Tracking Adaptative Threshold Accepting) metaheuristics have been implemented. The strategies proposed here consist in the implementation of constructive heuristics and the scatter search metaheuristic. The initial solutions of SS are obtained with the implementation of four constructive heuristics: saving heuristics, sequential insertion heuristic based on the ideas of Solomon (1987), sequential insertion heuristic based on the ideas of Ho e Haugland (2004) and adaptation of the sequential insertion heuristic of Dullaert et al. (2002). For the real case, it was possible to reduce the total fleet cost, when comparing to the actual solution. At some instances of the three benchmark problems, the algorithms presented similar or better results when compared to the best solutions in the literature.
253

Estudo da programação de atividades de desenvolvimento de poços de petróleo marítimos. / Study of the scheduling problem of offshore oil wells development activities.

Gilberto Koji Nishioka 12 November 2013 (has links)
Este trabalho detalha o problema de programação de atividades de desenvolvimento de poços marítimos (PPADPM), cujo objetivo é definir o uso de sondas e navios, de forma a otimizar a produção de óleo dos poços marítimos. São apresentados cinco modelos baseados em programação linear-inteira mista (MILP) e um modelo gerado via programação por restrições (PR) para este problema. Concluiu-se que, dentre os modelos MILP, aquele baseado em variáveis que definem a ordem de execução das atividades apresenta os melhores resultados, tanto em termos de qualidade de soluções quanto em termos de tamanho do modelo. O aumento do tamanho da instância (em número de poços e/ou em número de recursos) traz como consequência um menor número de nós analisados dentro de um tempo limite de execução do modelo, ao mesmo tempo em que se observa que as estratégias de escolha de variáveis, de escolha de nós e de uso de solução inicial nos modelos MILP tornam-se ineficientes. Na comparação entre modelos MILP e o modelo baseado em PR, constatou-se que este último obteve as melhores soluções em mais de 90% dos casos analisados e, consistentemente, obteve mais soluções viáveis para cada instância. Entretanto, por não fornecer informações sobre a qualidade da solução, o modelo baseado em PR somente obtém a solução ótima ao analisar todo o espaço de busca do modelo; desta forma, este apenas chegou à solução ótima em instâncias com até quatro poços, enquanto alguns dos modelos MILP obtiveram a solução ótima para instâncias com até treze poços. / This work details the offshore wells activities on specialized resources scheduling problem, focusing on the optimization of the total oil production. A Constraint Programming (CP) model and five Mixed-Integer Linear Programming (MILP) models were studied. Among the linear models, those based on activities order variables are smaller, and led to the better solutions for almost all of the instances analyzed. As far as the size of the instances (number of wells and/or number of resources) increases, the number of branched nodes in a limited time decreases and, consequently, the influence of B&B nodes and variable selection strategies and of the initial guesses on the MILP model solution gets less efficient. Comparing best solutions for each instance, the CP model outperformed MILP models in 90% of the studied cases. In addition, the CP based model consistently found more solutions per instance than the MILP based models did. However, because the CP model does not give information on the quality of a solution (gap), it was only able to obtain optimal solutions for instances with up to four wells, while MILP based models found optimal solutions for instances up to thirteen wells.
254

Imobilização de β-D-frutofuranosídeo frutohidrolase em partículas de quitosana / Immobilization of β-D- fructofuranoside fructohydrolase on chitosan particles

Valério, Sheila Garziera January 2012 (has links)
A enzima β-D- frutofuranosídeo frutohidrolase (E.C. 3.2.1.26), também conhecida como invertase, é uma hidrolase capaz de clivar o dissacarídeo sacarose, gerando mistura equimolar de glicose e frutose (‘açúcar invertido’). A aplicação deste, bem como a dos monossacarídeos de modo isolado é bastante comum na indústria alimentícia, por exemplo na manufatura de recheios de doces, além de outras aplicações, como na indústria farmacêutica. O objetivo deste trabalho foi avaliar diferentes suportes e métodos de imobilização de uma invertase de Saccharomyces cerevisiae. Os experimentos feitos com filmes de celulose, macroesferas de quitosana, e o suporte comercial Immobead não apresentaram resultados conclusivos. A imobilização covalente unipontual da invertase em mistura de nano e agregados de nanopartículas de quitosana possibilitou a obtenção dos seguintes resultados: além desse suporte ser de fácil preparação e ativação, oferecendo grande área superficial para a imobilização, o derivado imobilizado apresentou alta recuperação da atividade, sendo utilizado o protocolo que permitiu obter 74,3 % de rendimento e 61,6 % de eficiência de imobilização. A temperatura (55 ºC) e o pH ótimos de atividade (4,5), estabilidade térmica e ao armazenamento não foram modificados pós-imobilização. A afinidade da invertase pelo substrato decaiu cerca de 3 vezes, devido à reduzida acessibilidade da sacarose ao sítio ativo da enzima. Porém, o parâmetro Vmax manteve-se constante, indicando que não houve perda na máxima conversão da sacarose em seus monossacarídeos. Através da imobilização foi possível obter excelente estabilidade operacional: 59 reusos com 100 % da atividade catalítica da enzima (bateladas de 30 min, sob suave agitação, com solução de sacarose 8 %, a 55 ºC). / The enzyme β-D- fructofuranoside fructohydrolase (E.C. 3.2.1.26), also known as invertase, is one hydrolase able to cleave the sucrose disaccharide, generating an equimolar mixture of glucose and fructose (‘invert sugar’). The application of invert sugar, as well the isolated monosaccharides is very common in the food industry, for example in the manufacture of filling of sweets, besides other applications, as in the pharmaceutical industry. The objective of this work was to evaluate different supports and immobilization methods of an invertase from Saccharomyces cerevisiae. The experiments performed with cellulose films, chitosan macrospheres and the commercial support Immobead did not present conclusive results. The unipoint covalent immobilization of invertase in a mixture of chitosan nano and aggregated nanoparticles made possible to obtain the following results: besides the easy preparation and activation of this support, offering high superficial area for enzyme immobilization, the immobilized derivative presented high activity recovery, which allowed getting 74.3 % of immobilization yield and 61.6 % of immobilization efficiency. The optimal temperature (55 ºC) and pH (4.5) for activity, thermal and storage stabilities were not modified after immobilization. The enzyme affinity for its substrate decreased about 3 folds, mainly due to the reduced accessibility of sucrose to the catalytic site of the enzyme. However the parameter Vmax remained constant, indicating that there was not loss in the maximal conversion of sucrose in its monosaccharides. Through the immobilization was possible to obtain excellent operational stability: 59 reuses with 100 % of the catalytic enzyme activity (batches of 30 min, under genlte stirring, with sucrose solution 8 %, 55 ºC).
255

Modelling a Complex Production Scheduling Problem : Optimization Techniques

sohier, emmanuel January 2006 (has links)
In this thesis, and complex real world problem, a sequence dependent scheduling of different product orders on a number of lines is addressed. Changeover costs occur between product orders belonging to different product groups. The operational research cycle is employed exploring different optimization techniques as mathematical modelling and heuristic approaches. The identification, implementation and demonstration of the techniques are supported with numerical results from experiments. One combination of different solution techniques is put forward. Some suggestions are done for reducing cost and increasing productivity.
256

On System Dynamics as an Approach for Manufacturing Systems Development

Linnéusson, Gary January 2009 (has links)
Improvement work in manufacturing industry usually focuses on the utilisation of equipment. System dynamics simulation is a potential tool for increasing the utilisation of systems. By using group model building and simulation it facilitates a common view and better informed decisions for change. However, a gap between theory and practice of how to implement these projects is identified, consequently the major question for this thesis. The approach for solving this problem used industrial case studies with action research character; including modelling and interviews affecting the actors in the studied systems. Together with literature studies these efforts contribute with identifying how system dynamics projects can be performed for manufacturing systems development. It is shown that the support for how to implement system dynamics projects is unsatisfying and general. During the research progress a framework of guidelines has crystallised in order to bridge the presented gap of this thesis. Finally, the results are considered to make it easier to support manufacturing systems development using system dynamics.
257

The World of the United States Foreign Policy Elite: A Case Study of the U.S. Foreign Policy Think Tanks' Debates in the General Elections of 2004, 2008, and 2012

Serri, Seyed Hamidreza 02 April 2015 (has links)
American foreign policy think tanks are an important part of the American foreign policy elite. By gathering data, publishing research, and reaching out to the public and government, think tanks help set the public debate agenda. The question I asked was whether these American foreign policy think tanks exhibited a shared worldview during the past three election cycles. I analyzed 7,000 documents (half a million verbs) published by the seven American foreign policy think tanks active in the three general elections of 2004, 2008, and 2012: the American Enterprise Institute, the Brookings Institution, the Carnegie Endowment for International Peace, the Cato Institute, the Council on Foreign Relations, the Heritage Foundation, and the RAND Corporation. To measure the collective and individual worldviews of these seven think tanks, I used the Profiler Plus software, which answered Alexander George’s operational code questions based on the transitive verbs for the Self and the Other. My research showed that the collectivity of the seven think tanks had three separate worlds of action with three different worldviews. It also showed that the worldview of the American collective Self was very stable across time. Another empirical finding was that from the perspective of the seven think tanks, the United States’ actions were the most similar to the actions of other great powers: Europe, China, and Russia. It was also shown that from the perspective of the seven think tanks, China was the most cooperative nation and Terrorists were the most conflictual actors in the world.
258

Problematika financování vozového parku v silniční dopravě / The issue of financing the fleet of road transport

Mašková, Veronika January 2009 (has links)
Graduate work uses decisions methods of management for decisions of individual options for financing the fleet. The result is a simple formula that can be used by small businesses to choice of financing a vehicle intended for business. Evaluation of options, using the real calculations are: financial leasing, operational leasing and loan.
259

Controlling / Controlling

Hriňáková, Daniela January 2014 (has links)
The topic of my diploma thesis is controlling. The first part is theoretical where I describe the history, meaning and functions of controlling. After that I also specify the methods of strategical, operational and cost controlling. The practical part applied method of controlling to the selected company. The aim of this study is to determine the benefits of controlling for the company. At the operational level it describes the process of controlling in the firm and there are given suggestions for its improvement. At the level of financial controlling it was analyzed indicators of financial analysis. As part of strategic controlling I prepared SWOT analysis with the purpose of finding the best strategy for the firm. At the end I will summarize the results of my thesis and I will point out the necessity of having the controlling established in company.
260

Návrh přepravních poštovních tras Středočeského kraje / A Draft of Postal Transport Routes of the Central Bohemian Region

Hodonský, Josef January 2011 (has links)
This thesis describes and analyzes the postal transportation network of Central Bohemian Region, shows an applications of operational management in transport and by Clarke - Wright algorithm with limited capacity of the vehicles and limited time of ride solves the design of new routes to reduce mileage while operating the branch network of the territory.

Page generated in 0.1172 seconds