973 resultados para Mine Production Scheduling
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Este trabalho apresenta a modelagem de um problema particular de Programação da Produção numa Fundição Automatizada e sua resolução por um algoritmo de busca heurística, que explora a estrutura do problema.
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Perhaps due to its origins in a production scheduling software called Optimised Production Technology (OPT), plus the idea of focusing on system constraints, many believe that the Theory of Constraints (TOC) has a vocation for optimal solutions. Those who assess TOC according to this perspective indicate that it guarantees an optimal solution only in certain circumstances. In opposition to this view and founded on a numeric example of a production mix problem, this paper shows, by means of TOC assumptions, why the TOC should not be compared to methods intended to seek optimal or the best solutions, but rather sufficiently good solutions, possible in non-deterministic environments. Moreover, we extend the range of relevant literature on product mix decision by introducing a heuristic based on the uniquely identified work that aims at achieving feasible solutions according to the TOC point of view. The heuristic proposed is tested on 100 production mix problems and the results are compared with the responses obtained with the use of Integer Linear Programming. The results show that the heuristic gives good results on average, but performance falls sharply in some situations. © 2013 Copyright Taylor and Francis Group, LLC.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Bibliography: p. 43.
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Thesis (M.S.) - University of Illinois at Urbana-Champaign.
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"April, 1987."
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"September 15, 1984."
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Includes bibliographical references.
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In today's market, the global competition has put manufacturing businesses in great pressures to respond rapidly to dynamic variations in demand patterns across products and changing product mixes. To achieve substantial responsiveness, the manufacturing activities associated with production planning and control must be integrated dynamically, efficiently and cost-effectively. This paper presents an iterative agent bidding mechanism, which performs dynamic integration of process planning and production scheduling to generate optimised process plans and schedules in response to dynamic changes in the market and production environment. The iterative bidding procedure is carried out based on currency-like metrics in which all operations (e.g. machining processes) to be performed are assigned with virtual currency values, and resource agents bid for the operations if the costs incurred for performing them are lower than the currency values. The currency values are adjusted iteratively and resource agents re-bid for the operations based on the new set of currency values until the total production cost is minimised. A simulated annealing optimisation technique is employed to optimise the currency values iteratively. The feasibility of the proposed methodology has been validated using a test case and results obtained have proven the method outperforming non-agent-based methods.
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Atualmente, uma organização industrial com vista a singrar no mercado global é fortemente influenciada por pressões que visam o aumento da eficiência global e consequente redução de custos operacionais. O desafio para as mesmas passa, portanto, por expurgar do produto tudo aquilo que não lhe acrescenta valor percetível pelo cliente e por maximizar a utilização dos vários recursos industriais instalados. No seguimento deste desafio, surge o Problema de Planeamento e Programação da Produção, ao qual é necessário dar uma resposta eficiente. Este projeto tem como objetivo estudar o problema da Programação da Produção numa indústria de pavimentos e revestimentos cerâmicos, desenvolvendo uma heurística construtiva capaz de traduzir com fiabilidade a realidade do processo produtivo da mesma e, se possível, auxiliar na sua resolução. O problema da programação da produção em estudo visa responder às questões: o quê, em que quantidade, quando e em que linha produzir, por forma a satisfazer as necessidades dos clientes num prazo previamente estipulado como admissível, garantindo o enchimento dos fornos ligados. Sem grandes constrangimentos ao normal lavor da Produção, pretende obter-se com a heurística planos de produção viáveis, que minimizem o tempo necessário para a conclusão do conjunto de referências com necessidades produtivas. O problema é também abordado através de um modelo exato como um problema de máquinas paralelas idênticas capacitado, com matriz de compatibilidades, setups de família e de subfamília e com lotes mínimos de produção. Quer a heurística quer o modelo de programação inteira mista desenvolvidos permitem obter planos de produção válidos, equivalentes aos obtidos atualmente pela empresa através dos meios de programação atuais, embora com um dispêndio de tempo muito inferior.
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Este artículo presenta la aplicación de la metodología Kanban y el análisis del efecto que puede generar en una empresa de fabricación de transformadores de distribución. Mediante la aplicación de la metodología propuesta es posible mejorar la programación de la producción, con el objetivo de reducir la cantidad de producto en proceso que no es utilizado, de forma que se reduzca el inventario. Para analizar el efecto de aplicar la metodología Kanban en la empresa, se utilizo la técnica de simulación, para lo cual se modelizan el proceso actual y el propuesto con las reglas de dicha metodología. A partir de los resultados que arrojan dichas modelizaciones, se observa que existe un mejoramiento en las líneas de producción cuando se utiliza la metodología Kanban.
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The purpose of this project was to investigate student learning in the areas of earth science and environmental responsibility using the subject of coal fires. Eastern Kentucky, where this study was performed, has several coal fires burning that affect the local air quality and may also affect the health of people living near them. This study was conducted during the regular education of 9th grade Earth Science classroom in Russell Independent Schools, located in Russell, Kentucky. Students conducted internet research, read current articles on the subject of coal fire emissions and effect on local ecology, and demonstrated what they learned through summative assessments. There were several aspects of coalmines and coal fires that students studied. Students were able to take this knowledge and information and use it as a learning tool to gain a better understanding of their own environment. Using the local history and geology of coalmines, along with the long tradition of mine production, was a very beneficial starting point, allowing students to learn about environmental impact, stewardship of their local environment, and methods of preserving and protecting the ecosystem.