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Conception et optimisation d'allocation de ressources dans les lignes d'usinage reconfigurables / Design and optimisation of resources allocation in reconfigurable machining linesEssafi, Mohamed 08 December 2010 (has links)
Les travaux de cette thèse concernent la conception et l’optimisation de lignes de transfert reconfigurables. L’objectif principal est de concevoir une ligne d’usinage à moindre coût tout en respectant les contraintes techniques, technologiques et économiques du problème. Le problème d’optimisation correspondant est un problème d’équilibrage de lignes d’usinage sujet à des contraintes spécifiques. Il consiste à affecter les opérations aux stations de travail en minimisant les coûts d’installation. En plus des contraintes habituelles de ce type de problème, à savoir, les contraintes de précédence, d’inclusion et d’exclusion, nous avons dû considérer des contraintes d’accessibilité. De plus, la spécificité principale des lignes reconfigurables par rapport aux lignes de transfert dédiées, vient de la réalisation en série des opérations. Celle-ci rend souvent nécessaire la mise en place de stations équipées de plusieurs centres d’usinage travaillant en parallèle pour obtenir les volumes de production souhaités. Enfin, l’utilisation d’une tête d’usinage mono-broche induit la prise en compte de temps inter-opératoire de déplacements et de changement d’outils qui dépendent de la séquence d’opérations. Dans un premier temps, nous avons proposé une modélisation mathématique du problème à l’aide d’un programme linéaire en nombres mixtes. Nous avons aussi développé des méthodes de calcul de bornes inférieures ainsi qu’une procédure de prétraitement. Cependant, les contraintes additionnelles rendent la résolution du problème d’équilibrage plus difficile que dans le cas des lignes dédiées, et l’approche proposée ne permet généralement pas de résoudre des instances de taille industrielle. Pour répondre à ce besoin, nous avons donc développé plusieurs méthodes de résolution approchées du problème en nous inspirant de métaheuristiques efficaces sur des problèmes d’optimisation combinatoire. / This work concerns the design and the optimization of reconfigurable transfer lines. The principle objective is to design a machining line with less cost while respecting the technological and economic constraints of the problem. The corresponding optimization problem is a transfer lines balancing problem subject to specific constraints. It consists to affect operations to workstations minimizing the installations cost. In addition to the habitual constraints of the transfer balancing problem, i.e. precedence, inclusion and exclusion constraints, we consider accessibility constraints. In addition, the principal specificity of reconfigurable lines compared to the dedicated transfer lines, comes from the sequential execution of operations. This often makes it necessary to set up stations with several machining centers working in parallel to achieve desired production volumes. Finally, the utilization of mono-spindle head machining center induces the inclusion of setup times between operations. This setup time is due to the time of displacement and change of tools which it depends of the operational sequence. We proposed firstly a mathematical formalization of the problem using a mixed integer program. We developed also several methods to calculate lower bounds and a pretreatment procedure. However, the additional constraints make the resolution of the considered balancing problem very difficult and the proposed approach generally does not solve instances of industrial size. To meet this need, we have developed several approximate resolution methods of the problem taking inspiration from effective Metaheuristics on combinatorial optimization problems.
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Lagrangian-informed mixed integer programming reformulationsKhuong, Paul Virak 12 1900 (has links)
La programmation linéaire en nombres entiers est une approche robuste
qui permet de résoudre rapidement de grandes instances de problèmes
d'optimisation discrète. Toutefois, les problèmes gagnent constamment
en complexité et imposent parfois de fortes limites sur le temps de
calcul. Il devient alors nécessaire de développer des méthodes
spécialisées afin de résoudre approximativement ces problèmes, tout en
calculant des bornes sur leurs valeurs optimales afin de prouver la
qualité des solutions obtenues.
Nous proposons d'explorer une approche de reformulation en nombres
entiers guidée par la relaxation lagrangienne. Après l'identification
d'une forte relaxation lagrangienne, un processus systématique permet
d'obtenir une seconde formulation en nombres entiers. Cette
reformulation, plus compacte que celle de Dantzig et Wolfe, comporte
exactement les mêmes solutions entières que la formulation initiale,
mais en améliore la borne linéaire: elle devient égale à la borne
lagrangienne.
L'approche de reformulation permet d'unifier et de généraliser des
formulations et des méthodes de borne connues. De plus, elle offre
une manière simple d'obtenir des reformulations de moins grandes
tailles en contrepartie de bornes plus faibles.
Ces reformulations demeurent de grandes tailles. C'est pourquoi nous
décrivons aussi des méthodes spécialisées pour en résoudre les
relaxations linéaires.
Finalement, nous appliquons l'approche de reformulation à deux
problèmes de localisation. Cela nous mène à de nouvelles formulations
pour ces problèmes; certaines sont de très grandes tailles, mais nos
méthodes de résolution spécialisées les rendent pratiques. / Integer linear programming is a robust and efficient approach to solve
large-scale instances of combinatorial problems. However, problems
constantly gain in complexity and sometimes impose strong constraints
on computation times. We must then develop specialised methods to
compute heuristic primal solutions to the problem and derive lower
bounds on the optimal value, and thus prove the quality of our primal
solutions.
We propose to guide a reformulation approach for mixed integer
programs with Lagrangian relaxations. After the identification of a
strong relaxation, a mechanical process leads to a second integer
formulation. This reformulation is equivalent to the initial one, but
its linear relaxation is equivalent to the strong Lagrangian dual.
We will show that the reformulation approach unifies and generalises
prior formulations and lower bounding approaches, and that it exposes
a simple mechanism to reduce the size of reformulations in return for
weaker bounds.
Nevertheless, our reformulations are large. We address this issue by
solving their linear relaxations with specialised methods.
Finally, we apply the reformulation approach to two location problems.
This yields novel formulations for both problems; some are very large
but, thanks to the aforementioned specialised methods, still
practical.
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Modèles déterministes et stochastiques pour la résolution numérique du problème de maintien de séparation entre aéronefs / Deterministic and stochastic models for the numerical resolution of the aircraft separation problemOmer, Jérémy, Jean, Guy 27 February 2013 (has links)
Cette thèse s’inscrit dans le domaine de la programmation mathématique appliquée à la séparation d’aéronefs stabilisés en altitude. L’objectif est le développement d’algorithmes de résolution de conflits aériens ; l’enjeu étant d’augmenter la capacité de l’espace aérien afin de diminuer les retards et d’autoriser un plus grand nombre d’aéronefs à suivre leur trajectoire optimale. En outre, du fait de l’imprécision des prédictions relatives à la météo ou à l’état des aéronefs, l’incertitude sur les données est une caractéristique importante du problème. La démarche suivie dans ce mémoire s’attache d’abord au problème déterministe dont l’étude est nettement plus simple. Pour cela, quatre modèles basés sur la programmation non linéaire et sur la programmation linéaire à variables mixtes sont développés en intégrant notamment un critère reflétant la consommation de carburant et la durée de vol. Leur comparaison sur un ensemble de scénarios de test met en évidence l’intérêt d’utiliser un modèle linéaire approché pour l’étude du problème avec incertitudes. Un champ de vent aléatoire, corrélé en temps et en espace, ainsi qu’une erreur gaussienne sur la mesure de la vitesse sont ensuite pris en compte.Dans un premier temps, le problème déterministe est adapté en ajoutant une marge sur la norme de séparation grâce au calcul d’une approximation des probabilités de conflits. Finalement, une formulation stochastique avec recours est développée. Ainsi, les erreurs aléatoires sont explicitement incluses dans le modèle afin de tenir compte de la possibilité d’ordonner des manoeuvres de recours lorsque les erreurs observées engendrent de nouveaux conflits. / This thesis belongs to the field of mathematical programming, applied to the separation of aircraft stabilised on the same altitude. The primary objective is to develop algorithms for the resolution of air conflicts. The expected benefit of such algorithm is to increase the capacity of the airspace in order to reduce the number of late flights and let more aircraft follow their optimal trajectory. Moreover, meteorological forecast and trajectory predictions being inexact,the uncertainty on the data is an important issue. The approach that is followed focuses on the deterministic problem in the first place because it is much simpler. To do this, four nonlinear and mixed integer linear programming models, including a criterion based on fuel consumption and flight duration, are developed. Their comparison on a benchmark of scenarios shows the relevance of using an approximate linear model for the study of the problem with uncertainties.A random wind field, correlated in space and time, as well as speed measures with Gaussianerrors are then taken into account. As a first step, the deterministic problem is adapted by computinga margin from an approximate calculation of conflict probabilities and by adding it tothe reference separation distance. Finally, a stochastic formulation with recourse is developed.In this model, the random errors are explicitly included in order to consider the possibility of ordering recourse actions if the observed errors cause new conflicts.
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Otimização de processos na indústria têxtil: modelos e métodos de solução / Optimization of processes in textile industry: models and solution methodsCamargo, Victor Claudio Bento de 12 September 2012 (has links)
As decisões operacionais de produção em uma indústria de fiação são planejadas na prática determinando soluções dos sub-problemas de dimensionamento e sequenciamento de lotes e da mistura de fardos de algodão. As tarefas são: definir o tamanho, a sequência, o tempo e alocação de cada lote de produção e quais fardos de algodão devem ser utilizados na produção. Por si só, os sub-problemas representam grandes desafios no planejamento da produção. Entretanto, para melhor representar o ambiente produtivo e alcançar custos de produção mais baixos, indústrias de processo, como as de fiação, procuram integrar mais e mais seus sub-problemas de planejamento. O objetivo dessa tese é apresentar modelos matemáticos e métodos de solução para auxiliar a tomada de decisão no nível operacional do planejamento da produção. Três formulações matemáticas para o dimensionamento e sequenciamento de lotes em um sistema de dois estágios com produção sincronizada são propostas. Um novo método baseado em programação matemática e metaheurísticas e também desenvolvida para a solucão desse sub-problema. Além disso, a integração das decisões relativas a matéria-prima (fardos de algodão) ao dimensionamento e sequenciamento de lotes é analisada. As novas formulações propostas representam de forma mais realista o problema de dimensionamento e sequenciamento de lotes da indústria de fiação e de indústrias de processo com ambiente produtivo similares. O método de solução encontra boas soluções para o problema e supera outros méodos similares presentes em softwares comerciais. Além disso, o método é geral o suficiente para a solução de outros problemas de otimização. O problema integrado de dimensionamento e sequenciamento de lotes e mistura comprovou que restrições relativas à qualidade dos fios influenciam os custos e viabilidade do planejamento da produção. O planejamento integrado dessas óperações trata o sistema considerando restrições que se relacionam, definindo planos de produção mais realistas / In the practice of a spinning industry, the operational decisions of the production planning are determined by the hierarchical solution of the lot-sizing and scheduling problem and the blending problem of the cotton bales. The tasks are: to define the size, sequence, timing and allocation of each production lot and to select which cotton bales are used for production. Each of these problems represents a large challenge in planning the production. However, in order to better represent the production environment and to reach lower production costs, process industries (as the spinning industry) are integrating more and more of the production sub-problems into the planning. The aim of this thesis is to propose novel mathematical models and solution methods to assist the decision maker to plan the production at the operational level. Three formulations for the synchronized two-stage lot sizing and scheduling are proposed. A new method based on mathematical programming and metaheuristics is also developed to solve this sub-problem. In addition, the integration of the lot sizing and scheduling with decisions related to the raw materials (cotton bales) is analyzed. The novel models represent a more realistic lot sizing and scheduling for the spinning industry and process industries of similar production environment. The solution method finds good solutions to the mentioned problem and outperforms other state-of-the-art methods incorporated in commercial softwares. Moreover, the method is general enough to solve other optimization problems. The integrated lot-sizing, scheduling and blending prove that constraints related to the yarn quality influence the costs and the feasibility of the production planning. The integrated planning of these operations approaches the system considering the constraint relationship and defines more realistic production plans
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Métodos quantitativos para o problema de dimensionamento e sequenciamento de lotes na indústria de embalagens de vidro / Quantitative methods for lot sizing and scheduling in glass containers industryFachini, Ramon Faganello 16 January 2015 (has links)
O problema de dimensionamento e sequenciamento de lotes vem sendo extensivamente estudado por pesquisadores da área de Pesquisa Operacional e há uma tendência de que tais trabalhos passem a cada vez mais integrar aspectos reais dos processos produtivos. Entretanto, percebe-se que os estudos conduzidos em alguns setores industriais negligenciam importantes restrições tecnológicos dos processos de produção e isso afasta esses trabalhos de Pesquisa Operacional de uma aplicação efetiva, como é o caso da indústria de embalagens de vidro. Neste contexto, propõe-se um modelo de programação inteira mista e um método de solução para o problema de dimensionamento e sequenciamentos de lotes na indústria de embalagens de vidro, sendo que este trabalho diferencia-se dos demais existentes na literatura por agregar restrições tecnológicas específicas desse processo produtivo. O modelo proposto, denominado CLSD-GCST, foi amplamente validado com base em um conjunto de testes com 40 instâncias de um problema real de uma grande empresa do setor no pacote comercial IBM ILOG CPLEX Optimization Studio Versão 12.5. A validação do modelo incluiu ainda uma análise de ganhos potenciais para o negócio de baseada no modelo SCOR. Já o método de solução proposto consiste em uma metaheurística de Busca em Vizinhança Variável (VNS) e se mostrou promissor para a solução do problema estudado, proporcionando resultados de qualidade em um baixo tempo computacional. Além disso, o VNS superou o Branch-and-Cut do CPLEX para grandes instâncias, nas quais o pacote comercial encontrou dificuldades. Por fim, o VNS proposto também foi validado por meio da análise de testes computacionais e suas principais características foram avaliadas sistematicamente, gerando um conjunto de informações que pode direcionar a utilização e, até mesmo, a evolução desse método em pesquisas futuras. / Lot sizing and scheduling problem has been extensively studied by Operations Research scientists and there is a tendency of incorporating more production processes real aspects in these researches. However, it can be noticed that studies conducted in some industrial sectors neglect important production process technological constraints and it keeps the Operations Research works away from an effective application, as happens with the glass containers industry. In this context, a mixed integer programming model and a solution method were proposed for glass containers industry lot sizing and scheduling problem, the main difference between this work and the others in literature is the inclusion of process specific technological constraints. The proposed model, named CLSD-GCST, was widely validated by a set of tests performed with 40 instances from a large company real problem using the commercial package IBM ILOG CPLEX Optimization Studio Version 12.5. The model validation also included a potential business earnings analysis based on SCOR framework. About the proposed solution method, it consists of a Variable Neighborhood Search (VNS) metaheuristic and it proved to be promising for the studied problem solution, providing good quality results in low computational time. Moreover, VNS overcame the CPLEX Branch-and-Cut for large instances, in which the commercial package found difficulties. Lastly, the proposed VNS was validated by means of computational tests analysis and its main characteristics were systematically evaluated, generating an information set that may direct this method application and even its evolution in future researches.
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MODELOS DE OTIMIZAÇÃO PLIM-FUZZY PARA O DIMENSIONAMENTO DE REDE E SELEÇÃO DE SERVIÇOS EM TELECOMUNICAÇÕES.Oliveira, Bruno Quirino de 12 March 2015 (has links)
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Previous issue date: 2015-03-12 / Telecommunications experience accelerated evolution. The environment is very
competitive and the volume of financial resources involved is significant. The variety of
available technologies makes system planning stage, a procedure not only desirable but
necessary, especially in a competitive environment. The use of comprehensive and flexible
methodologies that can assist in decision-making, based on mathematical optimization
models, it seems an inevitable way. This paper presents mathematical models based on
operational research, mixed integer linear programming (MILP) and fuzzy logic to assist in
strategic planning and decision-making, for the telecommunications industry, where they are
analyzed, discussed and applied optimization models approach node-arc and arc-path. The
analysis is focused on minimizing the cost given the expected demand. The main network
components, services and costs are identified and models are developed to determine the
network configuration or service. The models allow for greater flexibility and a high degree
of interaction with the planner. These characteristics make it possible to analyze various
scenarios where there is inaccuracy, both for the selection of services and for network
deployment. To ensure the practical validation of the methodology, results of computational
experiments are presented and discussed. Noteworthy are the results: (1) the possibility of
holding a multi-service planning, with the possibility of assigning priorities in the services
and care (2) effectiveness of the model for network deployment, which revealed a gain of 2%
in the optimal solution in a test instance of SNDlib repository. / As telecomunicações experimentam acelerada evolução. O ambiente é muito
competitivo e o volume de recursos financeiros envolvidos é significativo. A variedade de
tecnologias disponíveis faz da etapa de planejamento do sistema um procedimento não só
desejável como necessário, principalmente num ambiente de competitividade. A utilização de
metodologias abrangentes e flexíveis que possam auxiliar no processo de decisão,
fundamentadas em modelos matemáticos de otimização, parece um caminho inevitável. Este
trabalho apresenta modelos matemáticos baseados em pesquisa operacional, programação
linear inteira mista (PLIM) e lógica fuzzy para ajudar no planejamento estratégico e na tomada
de decisões, para o setor de telecomunicações, onde são analisados, aplicados e discutidos
modelos de otimização com abordagem nó-arco e arco-caminho. A análise é orientada à
minimização do custo atendendo a demanda prevista. Os principais componentes de rede, de
serviços e de custos são identificados e os modelos são desenvolvidos para determinar a
configuração de rede ou de prestação de serviços. Os modelos permitem uma maior
flexibilidade e um alto grau de interação com o planejador. Estas características possibilitam
analisar variados cenários onde há imprecisão, tanto para a seleção de serviços, quanto para a
implantação de rede. Para garantir a validação prática da metodologia desenvolvida,
resultados de experimentos computacionais são apresentados e discutidos. Destacam-se nos
resultados: (1) a possibilidade de realizar um planejamento multi-serviço, com possibilidade
de atribuir prioridades no atendimento dos serviços e (2) eficácia do modelo, para a
implantação de rede, onde se obteve um ganho de 2% na solução ótima, em uma instância de
teste do repositório SNDlib.
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Models and algorithms for high school timetabling problems / Modelos e algoritmos para problemas de horários escolaresSaviniec, Landir 18 December 2017 (has links)
High school timetabling problems consist in assigning meetings between classes and teachers, with the goal of minimizing the violation of specific soft requisites. This category of problems has been extensively studied since the 1950s, mostly via mixed-integer programming and metaheuristic techniques. However, the computation of optimal or near-optimal solutions using mixed-integer programs or metaheuristics is still a challenge for most practical problems. In this thesis, we investigate new mixed-integer programming formulations, column generation approaches and parallel metaheuristic based algorithms to compute lower bounds and solutions for high school timetabling problems. Extensive computational experiments conducted with real-world instances demonstrate that our best formulations are competitive with best-known formulations, while our parallel algorithms present superior performance than the state-of-the-art methods. / Problemas de horários escolares consistem em alocar encontros entre turmas e professores, com objetivo de minimizar violações a requisitos qualitativos específicos. Esta categoria de problemas tem sido largamente estudada desde 1950, particularmente via técnicas de programação linear inteira mista e metaheurísticas. Entretanto, a computação de soluções ótimas ou quase ótimas usando programas inteiro-mistos ou metaheurísticas ainda é um desafio na maioria dos problemas práticos. Nesta tese, nós investigamos novas formulações inteiro-mistas, decomposições por geração de colunas e algoritmos baseados em metaheurísticas paralelas para computar limitantes inferiores e soluções para problemas de horários escolares. Extensivos experimentos computacionais conduzidos com instâncias reais demonstram que nossas melhores formulações são competitivas com as melhores formulações existentes, enquanto nossos algoritmos paralelos são superiores em performance computacional quando comparados com métodos que são estado-da-arte.
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Um estudo do problema de escolha de portfólio ótimo / A study about the portfolio selection problemAlbuquerque, Guilherme Ulliana Vieira de 08 May 2009 (has links)
O processo de escolha de portfólios é um problema clássico da área financeira. Neste problema, o investidor busca aplicar seu dinheiro em um mercado de ações de forma a obter um bom compromisso entre o retorno esperado e o risco. Em geral, quanto maior o retorno esperado da carteira, maior o risco a ela associado. Neste trabalho foram estudadas modelagens para o problema de escolha de portfólio ótimo e suas aplicações ao mercado brasileiro. Do ponto de vista de modelagem foi proposta a inclusão do risco diversificável e não-diversificável ao modelo linear estudado. O risco diversificável foi incluído através de uma restrição que impõe um número mínimo de ativos na composição do portfólio ótimo, enquanto o risco não-diversificável foi adicionado considerando o beta da carteira. Do ponto de vista de aplicação, foi considerada a atribuição de valores de probabilidade para os retornos históricos dos ativos utilizados na análise do problema, visando incorporar informações do comportamento apresentado pelo mercado nos resultados. Na geração dos resultados, foram desenvolvidos em CPLEX um método ótimo de solução para o problema e um método para geração de uma curva de soluções Pareto ótimas / The process of selecting a portfolio is a classical problem in finance, where the investor intends to invest money in the stock market in such way that a reasonable trade-off between expected return and risk is obtained. In general, the higher the expected return of the portfolio is, the higher his risk will be. In this work the single period portfolio optimization problem is studied in terms of modeling and application for the Brazilian stock market. Referring to the model, changes are proposed to include the diversifiable and nondiversifiable risk. The diversifiable risk is included by imposing a minimum number of assets on the portfolio, while the nondiversifiable risk is controlled by restricting the portfolios beta. On the applications side, a method to estimate the probability of the assets historical returns is proposed, so more information about the market behavior is considered on the problem. The results were obtained by a optimal method to find the best solution and another one to generate the Pareto-optimal solutions, both developed using CPLEX
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Métodos quantitativos para o problema de dimensionamento e sequenciamento de lotes na indústria de embalagens de vidro / Quantitative methods for lot sizing and scheduling in glass containers industryRamon Faganello Fachini 16 January 2015 (has links)
O problema de dimensionamento e sequenciamento de lotes vem sendo extensivamente estudado por pesquisadores da área de Pesquisa Operacional e há uma tendência de que tais trabalhos passem a cada vez mais integrar aspectos reais dos processos produtivos. Entretanto, percebe-se que os estudos conduzidos em alguns setores industriais negligenciam importantes restrições tecnológicos dos processos de produção e isso afasta esses trabalhos de Pesquisa Operacional de uma aplicação efetiva, como é o caso da indústria de embalagens de vidro. Neste contexto, propõe-se um modelo de programação inteira mista e um método de solução para o problema de dimensionamento e sequenciamentos de lotes na indústria de embalagens de vidro, sendo que este trabalho diferencia-se dos demais existentes na literatura por agregar restrições tecnológicas específicas desse processo produtivo. O modelo proposto, denominado CLSD-GCST, foi amplamente validado com base em um conjunto de testes com 40 instâncias de um problema real de uma grande empresa do setor no pacote comercial IBM ILOG CPLEX Optimization Studio Versão 12.5. A validação do modelo incluiu ainda uma análise de ganhos potenciais para o negócio de baseada no modelo SCOR. Já o método de solução proposto consiste em uma metaheurística de Busca em Vizinhança Variável (VNS) e se mostrou promissor para a solução do problema estudado, proporcionando resultados de qualidade em um baixo tempo computacional. Além disso, o VNS superou o Branch-and-Cut do CPLEX para grandes instâncias, nas quais o pacote comercial encontrou dificuldades. Por fim, o VNS proposto também foi validado por meio da análise de testes computacionais e suas principais características foram avaliadas sistematicamente, gerando um conjunto de informações que pode direcionar a utilização e, até mesmo, a evolução desse método em pesquisas futuras. / Lot sizing and scheduling problem has been extensively studied by Operations Research scientists and there is a tendency of incorporating more production processes real aspects in these researches. However, it can be noticed that studies conducted in some industrial sectors neglect important production process technological constraints and it keeps the Operations Research works away from an effective application, as happens with the glass containers industry. In this context, a mixed integer programming model and a solution method were proposed for glass containers industry lot sizing and scheduling problem, the main difference between this work and the others in literature is the inclusion of process specific technological constraints. The proposed model, named CLSD-GCST, was widely validated by a set of tests performed with 40 instances from a large company real problem using the commercial package IBM ILOG CPLEX Optimization Studio Version 12.5. The model validation also included a potential business earnings analysis based on SCOR framework. About the proposed solution method, it consists of a Variable Neighborhood Search (VNS) metaheuristic and it proved to be promising for the studied problem solution, providing good quality results in low computational time. Moreover, VNS overcame the CPLEX Branch-and-Cut for large instances, in which the commercial package found difficulties. Lastly, the proposed VNS was validated by means of computational tests analysis and its main characteristics were systematically evaluated, generating an information set that may direct this method application and even its evolution in future researches.
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TWO ESSAYS ON WHOLE FARM MODELING AND CROP MARKETING IN WESTERN KENTUCKYMartin, Benjamin A. 01 January 2018 (has links)
This thesis is composed of two essays that investigate whole farm planning and crop marketing in western Kentucky. In the first essay, contracting decisions between food corn producers and a mill are analyzed to observe factors affecting the bushel amount farmers contract. Unbalanced panel data containing seven years’ worth of pricing and contract information are used with a fixed-effects model to generate parameter estimates and quantify their effect on bushels contracted. It was found that contract attributes, market condition, and relationship-specific assets had a significant effect on producers’ food corn contracting decisions. The second essay utilizes mixed-integer programming to optimize resource allocation and marketing strategy for a hypothetical farm. Post-optimal analysis is performed to determine non-binding capacities for drying and storage equipment. The model is re-run with these non-binding capacities to observe changes in net returns as well as planting, harvesting, and marketing strategies. New equipment and associated costs are identified, and the change in net returns from the base case is used as net cash flow in a net present value investment analysis. Results of the investment analysis indicate increasing drying and storage capacity is a wise investment given the scenario modeled.
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