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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.
101

Optimisation numérique appliquée à la gestion de crise : Approche basée sur un algorithme hybride pour la résolution du problème intégré d'ordonnancement et d'allocation des ressources. / Numerical optimization applied to crisis management : A hybrid approach for solving the integrated problem of scheduling and resource allocation.

Khorbatly, Mohamad 24 October 2018 (has links)
Les travaux présentes dans cette thèse s'inscrivent dans le cadre des méthodes d'évacuation des populations. Ils visent à étudier les capacités et modéliser le problème d'évacuation (blessés, sinistrés, enfants, personnes agées, etc.) dans une situation de crise (attentats terroristes, catastrophes naturelles, etc.) et développer des méthodes d'aide à la décision tout en proposant une meilleure planification et des plans optimaux d'évacuation des populations de la zone de crise vers les centres hospitaliers.Notre travail consiste à résoudre le problème d'évacuation de blessés dans des zones de crise avec une nouvelle vision qui consiste à optimiser le temps de transport et par conséquent sauver le maximum des personnes touchées par cette crise d'une façon dynamique, efficace et rapide pour minimiser la perte humaine. / The work presented in this thesis is part of human evacuation methods. It aims to study the capacities, model the evacuation problem (wounded, victims, children, elderly, etc.) in a crisis situation (terrorist attacks, natural disasters, etc.) and to develops methods for decision making while proposing better planning and optimal evacuation plans for populations from the crisis zone to hospitals.Our job is to solve the wounded evacuation problem in crisis zone with a new vision that optimizes the transport time and thus saving the maximum of causalities in a dynamic, efficient and fast way in order to minimize human loss.
102

Aplicação de Inteligência Computacional para a Solução de Problemas Inversos de Transferência Radiativa em Meios Participantes Unidimensionais / Applying Computational Intelligence for the Solution of Inverse Problems of Radiative Transfer in Participating Media dimensional

Raphael Luiz Gagliardi 28 March 2010 (has links)
Esta pesquisa consiste na solução do problema inverso de transferência radiativa para um meio participante (emissor, absorvedor e/ou espalhador) homogêneo unidimensional em uma camada, usando-se a combinação de rede neural artificial (RNA) com técnicas de otimização. A saída da RNA, devidamente treinada, apresenta os valores das propriedades radiativas [ω, τ0, ρ1 e ρ2] que são otimizadas através das seguintes técnicas: Particle Collision Algorithm (PCA), Algoritmos Genéticos (AG), Greedy Randomized Adaptive Search Procedure (GRASP) e Busca Tabu (BT). Os dados usados no treinamento da RNA são sintéticos, gerados através do problema direto sem a introdução de ruído. Os resultados obtidos unicamente pela RNA, apresentam um erro médio percentual menor que 1,64%, seria satisfatório, todavia para o tratamento usando-se as quatro técnicas de otimização citadas anteriormente, os resultados tornaram-se ainda melhores com erros percentuais menores que 0,04%, especialmente quando a otimização é feita por AG. / This research consists in the solution of the inverse problem of radiative transfer for a participating media (emmiting, absorbing and/or scattering) homogeneous one-dimensional in one layer, using the combination of artificial neural network (ANN), with optimization techniques. The output of the ANN, properly trained presents the values of the radiative properties [w, to, p1 e p2] that are optimized through the following techniques: Particle Collision Algorithm (PCA), Genetic Algorithm (GA), Greedy Randomized Adaptive Search Procedure (GRASP) and Tabu Search (TS). The data used in the training are synthetics, generated through the direct problem without the introduction of noise. The results obtained by the (ANN) alone, presents an average percentage error minor than 1,64%, what it would be satisfying, however, for the treatment using the four techniques of optimization aforementioned, the results have become even better with percentage errors minor than 0,03%, especially when the optimization is made by the GA.
103

Abordagens heurísticas aplicadas ao Problema da Alocação Dinâmica de Espaços.

Costa, Wagner Silva 12 August 2013 (has links)
Made available in DSpace on 2015-05-14T12:36:37Z (GMT). No. of bitstreams: 1 ArquivoTotalWagner.pdf: 1537495 bytes, checksum: 24391c06b84eb789a63789d66472a304 (MD5) Previous issue date: 2013-08-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Dynamic Allocation Problem Spaces (DSAP) is recent literature, and was inspired by the need to minimize the distances between requested resources for the execution of activities in nuclear power plants. There are similarities of the problem with projects in which the movement of resources generates costs for the final planning, or in cases where congestion of these resources is not advisable, as in large buildings or works in mining. It is necessary, the use of these approximation methods considered to be NP hard. For this, a new constructive heuristic is proposed using integer linear programming model based on activity streams that incorporate information from the graph of dependencies between activities, and then an application of the hybrid GRASP meta-heuristic is discussed. The computational results show that this approach is able to obtain high-quality solutions. / O Problema da Alocação Dinâmica de Espaços (PADE) foi inspirado na necessidade de otimização da distância percorrida por recursos requeridos para realização de atividades na ocorrência de desligamentos planejados em centrais de energia elétrica. Em geral, o problema apresenta aplicações potenciais em projetos nos quais movimentar um recurso é uma tarefa difícil ou cara, ou nos quais o congestionamento desses recursos é indesejável,como em atividades de mineração.Este problema é computacionalmente difícil de se resolvido, logo obter uma solução ótima para instâncias de elevadas dimensões justica o uso de métodos aproximativos. Este trabalho propõe a utilização da metaheurística GRASP para a resolução do PADE.
104

O problema integrado de dimensionamento e sequenciamento de lotes no processo de fabricação da cerveja: modelos e métodos de solução / The integrated lot sizing and scheduling problem in the brewing process: models and solution methods

Tamara Angélica Baldo 19 August 2014 (has links)
Este trabalho aborda o problema multiestágio de planejamento e programação da produção em indústrias cervejeiras. O processo de fabricação de cerveja pode ser dividido em duas etapas principais: preparação do líquido e envase. A primeira etapa ocorre, na maior parte do tempo, dentro de tanques de fermentação e maturação. A segunda ocorre nas linhas de envase, podendo ter início assim que o líquido estiver pronto nos tanques. O tempo de preparação do líquido demora vários dias, enquanto que na maioria das indústrias de bebidas carbonatadas este tempo é de no máximo algumas horas. O objetivo deste estudo é obter planos de produção viáveis que visam otimizar as decisões de programação envolvidas nestes processos. Visitas a cervejarias no Brasil e em Portugal foram realizadas para uma maior familiaridade do processo de produção e dados foram coletados. Modelos de programação inteira mista para representar o problema foram desenvolvidos, baseados em abordagens CSLP (The Continuous Setup Lot-Sizing Problem), GLSP (General Lot Sizing and Scheduling Problem), SPL (Simple Plant Location Problem) e ATSP (Asymmetric Travelling Salesman Problem). Os resultados mostram que os modelos são coerentes e representam adequadamente o problema, entretanto, mostram-se difíceis de serem resolvidos na otimalidade. Esta dificuldade de resolução dos modelos motivou o desenvolvimento de procedimentos MIP-heurísticos, como também de uma metaheurística GRASP (Greedy Randomized Adaptive Search Procedure). As soluções obtidas pelos procedimentos heurísticos são de boa qualidade, quando comparadas ao melhor limitante inferior encontrado por meio da resolução dos modelos matemáticos. Os testes computacionais foram realizados utilizando instâncias geradas com base em dados reais. / This study deals with the multistage lot-sizing and scheduling problem in breweries. The brewing process can be divided into two main stages: preparation and filling of the liquid. The first stage occurs most of the time in fermentation and maturation tanks. The second stage occurs in the filling lines and it can start as soon as the liquid gets ready. The preparation time of the liquid takes several days, while in the carbonated beverage industries this time is at most a few hours. The purpose of this study is to obtain feasible production plans aimed at optimizing the decisions involved in these processes. Visits to brewery industries in Brazil and Portugal were held to a greater familiarity of the production process and data were collected. Mixed integer programming models have been developed to represent the problem, based on approaches for the CSLP (The Continuous Setup Lot-Sizing Problem), GLSP (General Lot Sizing and Scheduling Problem), SPL (Simple Plant Location Problem) and ATSP (Asymmetric Travelling Salesman Problem). The results show that the models are consistent and adequately represent the problem; however, they are difficult to be solved at optimality. This motivated the development of MIP-heuristic procedures, as well as a meta-heuristic GRASP (Greedy Randomized Adaptive Search Procedure). The obtained solutions by the heuristics are of good quality, when compared to the best lower bound found by solving the mathematical models. The tests were conducted using generated instances based on real data.
105

Melhorando o desempenho da técnica de clusterização hierárquica single linkage utilizando a metaheurística GRASP

Ribeiro Filho, Napoleão Póvoa 30 March 2016 (has links)
O problema de clusterização (agrupamento) consiste em, a partir de uma base de dados, agrupar os elementos de modo que os mais similares fiquem no mesmo cluster (grupo), e os elementos menos similares fiquem em clusters distintos. Há várias maneiras de se realizar esses agrupamentos. Uma das mais populares é a hierárquica, onde é criada uma hierarquia de relacionamentos entre os elementos. Há vários métodos de se analisar a similaridade entre elementos no problema de clusterização. O mais utilizado entre eles é o método single linkage, que agrupa os elementos que apresentarem menor distância entre si. Para se aplicar a técnica em questão, uma matriz de distâncias é a entrada utilizada. Esse processo de agrupamento gera ao final uma árvore invertida conhecida como dendrograma. O coeficiente de correlação cofenética (ccc), obtido após a construção do dendrograma, é utilizado para avaliar a consistência dos agrupamentos gerados e indica o quão fiel o dendrograma está em relação aos dados originais. Dessa forma, um dendrograma apresenta agrupamentos mais consistentes quando o ccc for o mais próximo de um (1) . O problema de clusterização em todas as suas vertentes, inclusive a clusterização hierárquica (objeto de estudo nesse trabalho), pertence a classe de problemas NP-Completo. Assim sendo, é comum o uso de heurísticas para obter soluções de modo eficiente para esse problema. Com o objetivo de gerar dendrogramas que resultem em melhores ccc, é proposto no presente trabalho um novo algoritmo que utiliza os conceitos da metaheurística GRASP. Também é objetivo deste trabalho implementar tal solução em computação paralela em um cluster computacional, permitindo assim trabalhar com matrizes de dimensões maiores. Testes foram realizados para comprovar o desempenho do algoritmo proposto, comparando os resultados obtidos com os gerados pelo software R. / The problem of clustering (grouping) consists of, from a database, group the elements so that more queries are in the same cluster (group) and less similar elements are different clusters. There are several ways to accomplish these groupings. One of the most popular is the hierarchical, where a hierarchical relationships between the elements is created. There are several methods of analyzing the similarity between elements in the clustering problem. The most common among them is the single linkage method, which brings together the elements that are experiencing less apart. To apply the technique in question, distance matrix is the input used. This grouping process generates the end an inverted tree known as dendrogram. The cophenetic correlation coefficient (ccc), obtained after the construction of the dendrogram is a measure used to evaluate the consistency of the clusters generated and indicates how faithful he is in relation to the original data. Thus, a dendrogram gives more consistent clusters when the ccc is closer to one (1). The clustering problem in all its aspects, including hierarchical clustering (object of study in this work), belongs to the class of NP-complete problems. Therefore, it is common to use heuristics for efficient solutions to this problem. In order to generate dendrograms that result in better ccc, it is proposed in this paper a new algorithm that uses the concepts of GRASP metaheuristic. It is also objective of this work to implement such a solution in parallel computing in a computer cluster, thus working with arrays larger. Tests were conducted to confirm the performance of the proposed algorithm, comparing the results with those generated by the software R.
106

Tecnologia & vida: a tomada de consciência no processo de formação docente

Mainine, Sueli 05 June 2014 (has links)
Made available in DSpace on 2016-04-27T14:31:22Z (GMT). No. of bitstreams: 1 Sueli Mainine.pdf: 8620441 bytes, checksum: 4911809694737f7d7d09cfe05ee4fadc (MD5) Previous issue date: 2014-06-05 / TECHNOLOGY & LIFE: The grasp of consciousness in the process of Teacher Training , the object of the present research, focuses the Teacher Training in the UCA1 Project and the teacher's professional development equationing the technologies appropriation as a human right and as a way of essential personal empowerment to life with new conceptions of teaching and learning. Its strategic significance takes the essence of the teacher training via research-action, through an eco-systemic narrative of the concrete situations experienced during training. The informative and conscientizing proposal of the research-action is guided by the balance between the objectives with a practical feature and the ones with knowledge. It has got the instrumental objective of grasp of consciousness of the agents for the improvement of teachers‟ performance. By the ontological dimension the intention is to get to know the reality in its multiple dimensions, considering the complexity of facts which are linked: the technological appropriation, the critical reading of the facts and the pedagogical action contextualization in the process of training. The epistemological assumptions are guided towards the dialectical perspective to understand the impacts caused in the teachers team and their influences during training that end up with the grasp of consciousness and the raise of the patterns of competence in the teachers‟ ICT. It's argued that the ICT dialogue with the demands of interdisciplinary mind. Those suppositions have motivated the study of the basis that contributes to understand how the action in the training can bring to consciousness the internalization of the acts, and for the thoughts the grasp of consciousness, which characterizes the change in the way of thinking and constitutes as the empowerment of the teachers in public schools for an innovative pedagogical practice in consonance with the country's development and with the urgencies in the contemporary world. This work is based on the work of Piaget, J., and Freire, P., along with other authors who talk about the question of grasp of consciousness, awareness, complexity, education, knowledge, post-modernity and technologies. It is concluded that the Teacher Training of the Project UCA-MEC both establishes the conditions to the constitution of the teachers‟ grasp of consciousness discretely and adjusts the new conceptions of teaching and learning when it considers the premises of awareness. It shows the improvement of the professional development, raising of the patterns of competence in ICT, personal empowerment, transformation in the way of thinking and the curricular change. But, because of the difficulties of the system conditions, it did not bring any expressive advance to the grasp of consciousness and awareness / TECNOLOGIA & VIDA:: A Tomada de Consciiênciia no Processo de Formação Docentte , objeto desta pesquisa, trata da Formação Docente no Projeto UCA1 e versa sobre o desenvolvimento profissional do professor equacionando a apropriação das tecnologias como um direito humano e como forma de empoderamento pessoal essencial à vida com novas concepções de ensinar e aprender. Tem como significado estratégico captar a essência da formação docente via pesquisa-ação, por meio de uma narrativa ecossistêmica das situações concretas vivenciadas na formação. A proposta informativa e conscientizadora da pesquisa-ação é orientada pelo equilíbrio entre os objetivos de caráter prático e de conhecimento. Tem objetivo instrumental de tomada de consciência dos agentes implicados, para a melhoria da performance docente. Pela dimensão ontológica pretende-se conhecer a realidade em suas múltiplas dimensões, considerando a complexidade de fatos que têm nexo entre si: a apropriação tecnológica, a leitura crítica dos fatos e a contextualização da ação pedagógica no processo de formação. Os pressupostos epistemológicos guiam-se na direção da perspectiva dialética para entender os impactos produzidos na equipe docente e as influências no decurso da formação que desencadeiam a tomada de consciência e elevam os padrões de competência em TIC dos professores. Defende-se que as TIC dialogam com as demandas do raciocínio interdisciplinar. Tais suposições motivaram o estudo de fundamentos que contribuem para compreender como a ação na formação pode imprimir à consciência a interiorização dos atos, e ao pensamento a tomada de consciência, que caracteriza a mudança na forma de pensar e se constitui como empoderamento dos professores da rede pública para uma prática pedagógica em consonância com o desenvolvimento do país e com as urgências do mundo contemporâneo. O trabalho de pesquisa alicerça-se nas obras de Piaget, J., e Freire, P., além de outros autores que abordam a questão da tomada de consciência, da conscientização, complexidade, educação, conhecimento e tecnologias. Conclui-se que a Formação Docente do Projeto UCA-MEC tanto estabelece discretamente condições para que se constitua a tomada de consciência dos professores, quanto combina novas concepções de ensino e de aprendizagem quando leva em conta as premissas da conscientização. Evidencia melhora do desempenho profissional, elevação dos padrões de competência em TIC, empoderamento pessoal, indícios de transformação na forma de pensar e mudança curricular. Mas, pelas dificuldades dos condicionantes do sistema, ela não trouxe avanços mais expressivos à tomada de consciência e conscientização
107

Grasp planning methodology for 3D arbitrary shaped objects

Roa Garzón, Máximo Alejandro 11 June 2009 (has links)
La prensión y manipulación de objetos se ha convertido en un área de gran interés en robótica, especialmente debido al desarrollo de dispositivos de prensión diestra como las manos antropomórficas, que incrementan la flexibilidad y verstilidad de los brazos robóticos, permitiendo así la prensión y manipulación de una gran variedad de objetos con un solo efector final. Esta tesis aborda varios problemas de planificación asociados a la prensión y manipulación de objetos discretos arbitrarios, esto es, objetos de forma arbitraria descritos mediante nubes de puntos o mallas poligonales. La obtención de una prensión con clausura de fuerza (force-closure) y de una prensión localmente óptima se realiza mediante procedimientos de búsqueda orientada basados en razonamientos geométricos en el espacio de prensiones. La medida de calidad de prensión utilizada es la mayor fuerza generalizada de perturbación que la prensión puede resistir, independientemente de la dirección de la perturbación. Sin embargo, las manos mecánicas y dispositivos de prensión reales difícilmente pueden asegurar que los dedos toquen el objeto justamente en los puntos de contacto calculados. Las regiones de contacto independiente (ICRs) se definen de forma tal que un dedo colocado en cada ICR asegura una prensión con clausura de fuerza; estas regiones otorgan robustez frente a errores en el posicionamiento de los dedos. Esta tesis presenta un algoritmo para obtener las ICRs con cualquier número de contactos con o sin fricción sobre la superficie de cualquier objeto tridimensional, asegurando también una calidad mínima controlada. La aproximación planteada genera las ICRs creciéndolas alrededor de los puntos de contacto de una prensión inicial apropiada, por ejemplo una prensión localmente óptima. Este método se extiende también para el cálculo de ICRs cuando varios contactos están fijados de antemano. El concepto de regiones de no prensión (NGRs) se introduce en este trabajo. Las NGRs se definen de forma tal que un dedo colocado en cada NGR siempre produce una prensión sin clausura de fuerza, independientemente de la posición exacta de cada dedo. Las ICRs y NGRs se utilizan para explorar de forma eficiente el espacio de prensiones. Este espacio es construido mediante un método de muestreo que provee muestras de prensiones con o sin clausura de fuerza, que luego se utilizan para calcular ICRs o NGRs respectivamente, y que luego sirven para etiquetar las configuraciones del espacio de prensiones. Se presenta también una secuencia de muestreo determinístico que permite una exploración incremental y uniforme del espacio de prensiones. La generación del espacio de prensiones se utiliza posteriormente para resolver el problema de reprensión (regrasping), esto es, la obtención de trayectorias de las puntas de los dedos sobre la superficie del objeto para cambiar de una prensión inicial a una final sin perder la condición de la clausura de fuerza. La tesis incluye ejemplos de aplicación para ilustrar el desempeño y la relevancia de los algoritmos planteados. / Object grasping and manipulation has become an area of great interest in robotics, specially due to the development of dexterous grasping devices like anthropomorphic hands that increase the flexibility and versatility of the robot arms, allowing the grasping and manipulation of a large variety of objects with a single end effector. This thesis tackles several planning problems associated with grasping and manipulation of arbitrary discrete objects, i.e. objects described with a cloud of points or a polygonal mesh. The computation of a force closure grasp and a locally optimal grasp is tackled using oriented search procedures based on geometric reasoning in the wrench space. The grasp quality measure considered is the largest perturbation wrench that the grasp can resist independently of the perturbation direction. However, real mechanical hands and grasping devices can hardly assure that the fingers will precisely touch the object at the computed contact points. Independent contact regions (ICRs) such that a finger contact in each ICR ensures a force closure grasp, provide robustness in front of finger positioning errors. This thesis presents an approach to compute ICRs with any number of frictionless or frictional contacts on the surface of any 3D object, assuring a controlled minimum grasp quality. The approach generates the ICRs by growing them around the contact points of a given appropriated starting grasp, like for instance a locally optimal grasp. The approach is also extended to compute the ICRs when several contacts are fixed beforehand. The notion of Non-Graspable Regions (NGRs) is introduced in this work, such that a finger contact in each NGR always produces a non-force closure grasp independently of the exact position of each finger. The ICRs and NGRs are used to efficiently explore the grasp space. The grasp space is constructed using a sampling method that provides samples of force closure or non force closure grasps used to compute ICRs or NGRs, respectively, which are used to label the configurations of the grasp space. An efficient deterministic sampling sequence is provided to allow a good incremental and uniform exploration of the grasp space. The generation of the grasp space is then applied to solve the regrasping problem, i.e. to obtain trajectories of the fingertips on the object surface in order to change from an initial to a final grasp without losing the force closure condition. Application examples are included to illustrate the relevance and performance of the proposed approaches.
108

A finite element based dynamic modeling method for design analysis of flexible multibody systems

Liu, Chih-Hsing 05 April 2010 (has links)
This thesis develops a finite element based dynamic modeling method for design and analysis of compliant mechanisms which transfer input force, displacement and energy through elastic deformations. Most published analyses have largely based on quasi-static and lump-parameter models neglecting the effects of damping, torsion, complex geometry, and nonlinearity of deformable contacts. For applications such as handling of objects by the robotic hands with multiple high-damped compliant fingers, there is a need for a dynamic model capable of analyzing the flexible multibody system. This research begins with the formulation of the explicit dynamic finite element method (FEM) which takes into account the effects of damping, complex geometry and contact nonlinearity. The numerical stability is considered by evaluating the critical time step in terms of material properties and mesh quality. A general framework incorporating explicit dynamic FEM, topology optimization, modal analysis, and damping identification has been developed. Unlike previous studies commonly focusing on geometry optimization, this research considers both geometric and operating parameters for evaluation where the dynamic performance and trajectory of the multibody motion are particularly interested. The dynamic response and contact behavior of the rotating fingers acting on the fixed and moving objects are validated by comparing against published experimental results. The effectiveness of the dynamic modeling method, which relaxes the quasi-static assumption, has been demonstrated in the analyses of developing an automated transfer system involved grasping and handling objects by the compliant robotic hands. This FEM based dynamic model offers a more realistic simulation and a better understanding of the multibody motion for improving future design. It is expected that the method presented here can be applied to a spectrum of engineering applications where flexible multibody dynamics plays a significant role.
109

Home therapist network modeling

Shao, Yufen 03 February 2012 (has links)
Home healthcare has been a growing sector of the economy over the last three decades with roughly 23,000 companies now doing business in the U.S. producing over $56 billion in combined annual revenue. As a highly fragmented market, profitability of individual companies depends on effective management and efficient operations. This dissertation aims at reducing costs and improving productivity for home healthcare companies. The first part of the research involves the development of a new formulation for the therapist routing and scheduling problem as a mixed integer program. Given the time horizon, a set of therapists and a group of geographically dispersed patients, the objective of the model is to minimize the total cost of providing service by assigning patients to therapists while satisfying a host of constraints concerning time windows, labor regulations and contractual agreements. This problem is NP-hard and proved to be beyond the capability of commercial solvers like CPLEX. To obtain good solutions quickly, three approaches have been developed that include two heuristics and a decomposition algorithm. The first approach is a parallel GRASP that assigns patients to multiple routes in a series of rounds. During the first round, the procedure optimizes the patient distribution among the available therapists, thus trying to reach a local optimum with respect to the combined cost of the routes. Computational results show that the parallel GRASP can reduce costs by 14.54% on average for real datasets, and works efficiently on randomly generated datasets. The second approach is a sequential GRASP that constructs one route at a time. When building a route, the procedure tracks the amount of time used by the therapists each day, giving it tight control over the treatment time distribution within a route. Computational results show that the sequential GRASP provides a cost savings of 18.09% on average for the same real datasets, but gets much better solutions with significantly less CPU for the same randomly generated datasets. The third approach is a branch and price algorithm, which is designed to find exact optima within an acceptable amount of time. By decomposing the full problem by therapist, we obtain a series of constrained shortest path problems, which, by comparison are relatively easy to solve. Computational results show that, this approach is not efficient here because: 1) convergence of Dantzig-Wolfe decomposition is not fast enough; and 2) subproblem is strongly NP-hard and cannot be solved efficiently. The last part of this research studies a simpler case in which all patients have fixed appointment times. The model takes the form of a large-scale mixed-integer program, and has different computational complexity when different features are considered. With the piece-wise linear cost structure, the problem is strongly NP-hard and not solvable with CPLEX for instances of realistic size. Subsequently, a rolling horizon algorithm, two relaxed mixed-integer models and a branch-and-price algorithm were developed. Computational results show that, both the rolling horizon algorithm and two relaxed mixed-integer models can solve the problem efficiently; the branch-and-price algorithm, however, is not practical again because the convergence of Dantzig-Wolfe decomposition is slow even when stabilization techniques are applied. / text
110

Planification stratégique d'une Supply chain sous contraintes d'incertitude : affectation de la production et dimensionnement des ressources

Pernot, Pierre-Alban 18 December 2013 (has links) (PDF)
Ce doctorat a porté, pour partie, sur une problématique dérivée du cas de la Supply Chain Tourisme Camionnette Europe de la société Michelin. Celle-ci a été formulée comme un problème d'Affectation Stratégique des Productions et de Dimensionnement des Ressources ainsi que de la Flexibilité (ASPDRF) du système de production d'une Supply Chain dans un contexte incertain. Ce problème ASPDRF présentant un certain nombre de spécificités rendant impossible le recours à des méthodes existantes ; un modèle linéaire dédié ainsi qu'une métaheuristique de type " Greedy Randomized Adaptative Search Procedure " (GRAPS) ont été construits. Cette dernière a permis l'obtention de résultats de bonnes qualités et industriellement exploitables et, ce, même dans le cas d'instances de très grandes tailles ; instances ne pouvant être résolues par le recours à la programmation linéaire. Ceci constitue, en plus de l'originalité de certaines contraintes considérées, l'un des apports de ces travaux de doctorat vis-à-vis de la thématique du Supply Chain Network Design à laquelle ils se rattachent. Au-delà de la résolution du problème ASPDRF, ces travaux de doctorat ont également portés sur la réalisation d'un environnement intégré de planification couvrant les horizons stratégique, tactiques et opérationnels ainsi que les différentes boucles de rétroaction associées. Celui-ci a pour vocation d'apporter une aide au manager lors des différentes étapes de prises de décisions associées à ces horizons de planification. Cet environnement, constitué du GRASP proposé ainsi que de modèles de flot et de modèles linéaires spécifiques, présente lui aussi la particularité de pouvoir adresser des problèmes de grandes tailles.

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