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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.
41

Meta-heurísticas baseadas em busca em vizinhança variável aplicadas a problemas de operação de transportes. / Metaheuristic based on variable neighbourhood search applied to operation transport problems.

Jorge Von Atzingen dos Reis 30 September 2013 (has links)
Esta pesquisa trata da aplicação de meta-heurísticas baseadas em busca em vizinhança variável em problemas de operação de transportes. Desta forma, buscou-se encontrar problemas complexos durante a operação de sistemas de transportes, nas grandes cidades, que possam ser resolvidos com a aplicação de meta-heurística baseada em busca em vizinhança variável. Este trabalho aborda dois diferentes problemas de planejamento e operação de transportes. O primeiro problema abordado neste trabalho é o Problema de Programação da Tabela de Horários, de Veículos e de Tripulantes de Ônibus, no qual as viagens que comporão a tabela de horários, os veículos que executarão as viagens e as tripulações que operarão os veículos são alocadas simultaneamente e de maneira integrada. O segundo problema a ser abordado é o problema de distribuição física, o qual envolve o agrupamento e a alocação de entregas a uma frota de veículos visando minimizar o frete total. Uma abordagem para a modelagem matemática deste problema é modelar como um problema de bin-packing, com bins de tamanho variável unidimensional (do inglês Variable Sized Bin-Packing Problem - VSBPP), ou seja, uma generalização do tradicional problema de bin-packing no qual bins (veículos) de diferentes capacidades e custos estão disponíveis para a alocação de um conjunto de objetos (cargas), de modo que o custo total dos bins (veículos) utilizados seja mínimo. A outra abordagem proposta para o problema de distribuição física é modelar o problema como um problema de bin-packing, com bins de tamanho variável bidimensional (do inglês Bidimensional Variable Sized Bin-Packing Problem BiD-VSBPP). Assim sendo, trata-se de uma expansão do problema de bin-packing com bins de tamanho variável unidimensional (VSBPP), no qual bins (veículos) de diferentes capacidades (capacidade volumétrica e capacidade de carga) e custos estão disponíveis para a alocação de um conjunto de objetos (cargas), os quais possuem as dimensões peso e volume, de modo que o custo total dos bins (veículos) utilizados seja mínimo. Durante a realização deste trabalho, foi desenvolvido um programa computacional em C++, o qual implementa a meta-heurística Busca em Vizinhança Variável (VNS) e duas meta-heurísticas baseadas em VNS. São apresentados resultados de experimentos computacionais com dados reais e dados benchmarking. Os resultados obtidos comprovam a eficácia das meta-heurísticas propostas. / This work approaches variable neighborhood search meta-heuristic applicate on transport operation problems. This way, we sought find complex transport operation problems in large cities that can be solved with the variable neighborhood search meta-heuristic application. This work approaches two different transport planning and operation problems. The first problem approached in this paper is the Bus Timetable Vehicle Crew Scheduling Problem, in which timetabling, bus and crew schedules are simultaneously determined in an integrated approach. The second problem to be approached is the physical distribution problem which comprises grouping and assigning deliveries to a heterogeneous fleet of vehicles aiming to minimize the total freight cost. The problem can be mathematical modeled as one-dimensional Variable Sized Bin-Packing Problem (VSBPP), a generalization of the traditional bin-packing problem, in which bins (vehicles) with different sizes and costs are available for the assignment of the objects (deliveries) such that the total cost of the used bins (vehicles) is minimized. Another proposed approach to the problem of physical distribution is model as two dimensional Variable Sized Bin-Packing Problem (BiD-VSBPP). Therefore, it is an expansion of the bin-packing problem with bins variable-length-dimensional (VSBPP), in which bins (vehicle) of different capacity (capacity and load carrying capacity) and costs are available for allocation a set of objects (loads), which have the dimensions weight and volume, so that minimized the total cost of bins (vehicle). In this work, was developed a C++ software implemented, which was implemented a meta-heuristic Variable Neighborhood Search (VNS) and two others meta-heuristics based on VNS. Computational results for real-world problems and benchmarking problems are presented, showing the effectiveness of these proposed meta-heuristics.
42

Résolution conjointe des problèmes de planification des opérations chirurgicales et des opérations de maintenance : application au cas des hôpitaux camerounais / A joint resolution on planification problems in surgical and maintenance operations : case study Cameroonian hospitals

Pensi, Janvier 20 October 2017 (has links)
Les travaux de thèse présentés s’intéressent à l’optimisation des activités d’un bloc opératoire. Ces activités concernent les interventions chirurgicales à planifier et les interventions de maintenance préventive sur les équipements dans les salles d’opération. Une solution est la synchronisation de ces activités lors de la construction du planning opératoire au niveau opératoire. Nous dissocions deux stratégies de programmation opératoire : programmation ouverte et programmation avec allocation préalable des plages horaires aux chirurgiens. Pour chacune des stratégies, nous considérons deux cas : le cas où l’heure de début d’une intervention de maintenance dans la salle est fixée, ladite intervention précédant l’affection des interventions chirurgicales dans les salles. Le second cas étant celui où l’heure de début de maintenance varie dans un intervalle entre une heure de début minimum et une heure de début maximum, avec l’intervention de maintenance placée a posteriori.Nous faisons plusieurs propositions de méthodes (exactes et approchées), y compris une méthode hybride, qui repose sur le couplage entre une métaheuristique et une heuristique. Les résultats obtenus sur des instances générées en concertation avec le monde hospitalier sont intéressants. / The presented dissertation is about the optimization of hospital systems, more precisely the optimization of the activities of an operation theatre. These activities showcase the surgical procedures to be planned and the preventive maintenance interventions on the equipment in the operating rooms. One solution is the synchronization of these activities during the construction of the operational planning at the operational level.We dissociate two operating programming strategies: Open Scheduling or Open programming and Block Scheduling or Programming with prior allocation of times to surgeons. For each strategy two cases are considered: the first case is where the time of beginning of a maintenance intervention in the room is fixed - this intervention preceding the affection of the surgical interventions in the rooms. The second case is where the maintenance start time varies in the interval between a minimum start time and a maximum start time, with the maintenance intervention placed beforehand. We make several proposition’s methods (exact and approximate), including a hybrid method, which is based on the coupling between a metaheuristic and a heuristic. The results obtained on bodies generated in consultation with the hospital’s world are interesting.
43

Planification et affectation de ressources dans les réseaux de soin : analogie avec le problème du bin packing, proposition de méthodes approchées / Planning and resources assignment in healthcare networks : analogy with the bin packing problem, proposition of approximate methods

Klement, Nathalie 04 December 2014 (has links)
Les travaux de thèse présentés s’intéressent à l’optimisation des systèmes hospitaliers. Une solution existante est la mutualisation de ressources au sein d’un même territoire. Cela peut passer par différentes formes de coopération dont la Communauté Hospitalière de Territoire. Différents problèmes sont définis en fonction du niveau de décision : stratégique, tactique ou opérationnel ; et du niveau de modélisation : macroscopique, mesoscopique et microscopique. Des problèmes de dimensionnement, de planification et d’ordonnancement peuvent être considérés. Nous définissons notamment le problème de planification d’activités avec affectation de ressources. Plusieurs cas sont dissociés : soit les ressources humaines sont à capacité infinie, soit elles sont à capacité limitée et leur affectation sur site est une donnée, soit elles sont à capacité limitée et leur affectation sur site est une variable. Ces problèmes sont spécifiés et formalisés mathématiquement. Tous ces problèmes sont comparés à un problème de bin packing : le problème du bin packing de base pour le problème où les ressources humaines sont à capacité infinie, le problème du bin packing avec interdépendances dans les deux autres cas. Le problème du bin packing avec incompatibilités est ainsi défini. De nombreuses méthodes de résolution ont déjà été proposées pour le problème du bin packing. Nous faisons plusieurs propositions dont un couplage hiérarchique entre une heuristique et une métaheuristique. Des métaheuristiques basées individu et une métaheuristique basée population, l’optimisation par essaim particulaire, sont utilisées. Cette proposition nécessite un nouveau codage inspiré des problèmes de permutation d’ordonnancement. Cette méthode donne de très bons résultats sur les instances du problème du bin packing. Elle est simple à appliquer : elle couple des méthodes déjà connues. Grâce au couplage proposé, les nouvelles contraintes à considérer nécessitent d’être intégrées uniquement au niveau de l’heuristique. Le fonctionnement de la métaheuristique reste le même. Ainsi, notre méthode est facilement adaptable au problème de planification d’activités avec affectation de ressources. Pour les instances de grande taille, le solveur utilisé comme référence ne donne qu’un intervalle de solutions. Les résultats de notre méthode sont une fois encore très prometteurs : les solutions obtenues sont meilleures que la borne supérieure retournée par le solveur. Il est envisageable d’adapter notre méthode sur d’autres problèmes plus complexes par intégration dans l’heuristique des nouvelles contraintes à considérer. Il serait notamment intéressant de tester ces méthodes sur de réelles instances hospitalières afin d’évaluer leur portée. / The presented work is about optimization of the hospital system. An existing solution is the pooling of resources within the same territory. This may involve different forms of cooperation between several hospitals. Various problems are defined at the decision level : strategic, tactical or operational ; and at the modeling level : macroscopic, mesoscopic and microscopic. Problems of sizing, planning and scheduling may be considered. We define the problem of activities planning with resource allocation. Several cases are dissociated : either human resources are under infinite capacity, or they are under limited capacity and their assignment on a place is given, or they are under limited capacity and their assignment is a variable. These problems are specified and mathematically formalized. All thes problems are compared to a bin packing problem : the classical problem of bin packing is used for the problem where human resources are under infinite capacity, the bin packing problem with interdependencies is used in the two other cases. The bin packing problem with incompatibilities is defined. Many resolution methods have been proposed for the bin packing problem. We make several propositions including a hierarchical coupling between heuristic and metaheuristic. Single based metaheuristics and a population based metaheuristic, the particle swarm optimization, are used. This proposition requires a new encoding inspired by permutation problems. This method gives very good results to solve instances of the bin packing problem. It is easy to apply : it combines already known methods. With the proposed coupling, the new constraints to be considered need to be integrated only on the heuristic level. The running of the metaheuristic is the same. Thus, our method is easily adaptable to the problem of activities planning with resource allocation. For big instances, the solver used as a reference returns only an interval of solutions. The results of our method are once again very promising : the obtained solutions are better than the upper limit returned by the solver. It is possible to adapt our method on more complex issues through integration into the heuristic of the new constraints to consider. It would be particularly interesting to test these methods on real hospital authorities to assess their significance.
44

Dėžių pakavimo trimatėje erdvėje algoritmas ir jo taikymas logistikos uždaviniams spręsti / The algorithm of 3D bin packing and it application in logistics

Ražas, Artūras 31 May 2006 (has links)
Whether you are in industrial manufacturing striving to optimize your supply chain, international or domestic carrier committed to lower your operational costs, retailer dedicated to run your distribution network more efficiently, or anywhere else where the words "cargo", "freight", "shipment" are in your business language, automated load planning and optimization will significantly improve your business process. While the concept of computerized simulation of 3D load building is not new, with some companies offering software solutions for "virtual" loading, no one has a single product that is capable to handle complex variety of business rules and constraints of the modern transportation industry. We are analyzing the problems related with 3D box loading and then to analyze existing 3D load building systems. After accumulating all analyzes data we are having enough experience to create our own algorithm. And we did it! We create 3D box loading algorithm witch is fast and accurate and 3D box loading system which is using this new algorithm. To ensure that we succeeded we compare this new system with existing 3D box loading software to make sure that it’s really useful for solving logistic problems. After testing we are sure that we made a big job and we have created system, which can compete with the logistic IT leaders made solutions.
45

Meta-heurística age-e aplicada a problemas de carregamento de contêiners /

Lima, Bruna Gonçalves de January 2017 (has links)
Orientador: Rubén Augusto Romero Lázaro / Resumo: Neste trabalho apresenta-se uma nova meta-heurística, o Algoritmo Genético Evolucionário Especializado (AGE-E) para resolver uma das categorias dos Problemas de Carregamento de Contêiners, objeto de estudo que pertence à otimização, na Pesquisa Operacional. Considera-se a existência de múltiplos contêiners de iguais dimensões que permitem o carregamento completo da carga disponível em um contexto de transporte industrial. Esta carga é composta por caixas de sortimento fortemente hete-rogêneo e que permite a rotação em qualquer dasseis possibilidades, tornando o problema ainda mais complexo, e, porisso,menos estudado na literatura. Uma revisão bibliográfica é também apresentada, contendo uma visão geral das classificações do problema e, em particular, um estudo aprofundado sobre algoritmos genéticos. A implementação do AGE-E foi realizada, e os resultados computacionais foram comparados com as melhores soluções já apresentadas na literatura, demonstrando o potencial do AGE-E para estudosfuturos. / Doutor
46

Meta-heurística age-e aplicada a problemas de carregamento de contêiners / Age-e metaheuristics applied to bin packing problems

Lima, Bruna Gonçalves de [UNESP] 06 September 2017 (has links)
Submitted by BRUNA DE LIMA ALCANTARA KITAMURA null (brunakitamura@yahoo.com.br) on 2017-10-30T20:10:34Z No. of bitstreams: 1 TESE-FINAL-BRUNA-G-LIMA.pdf: 4015697 bytes, checksum: cb6eb178262689807dbc777ab5d4d4dd (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-11-09T18:45:51Z (GMT) No. of bitstreams: 1 lima_bg_dr_ilha.pdf: 4015697 bytes, checksum: cb6eb178262689807dbc777ab5d4d4dd (MD5) / Made available in DSpace on 2017-11-09T18:45:51Z (GMT). No. of bitstreams: 1 lima_bg_dr_ilha.pdf: 4015697 bytes, checksum: cb6eb178262689807dbc777ab5d4d4dd (MD5) Previous issue date: 2017-09-06 / Neste trabalho apresenta-se uma nova meta-heurística, o Algoritmo Genético Evolucionário Especializado (AGE-E) para resolver uma das categorias dos Problemas de Carregamento de Contêiners, objeto de estudo que pertence à otimização, na Pesquisa Operacional. Considera-se a existência de múltiplos contêiners de iguais dimensões que permitem o carregamento completo da carga disponível em um contexto de transporte industrial. Esta carga é composta por caixas de sortimento fortemente hete-rogêneo e que permite a rotação em qualquer dasseis possibilidades, tornando o problema ainda mais complexo, e, porisso,menos estudado na literatura. Uma revisão bibliográfica é também apresentada, contendo uma visão geral das classificações do problema e, em particular, um estudo aprofundado sobre algoritmos genéticos. A implementação do AGE-E foi realizada, e os resultados computacionais foram comparados com as melhores soluções já apresentadas na literatura, demonstrando o potencial do AGE-E para estudosfuturos. / This work presents a new meta-heuristic, the Specialized Evolutionary Genetic Algorithm (AGE-E), which solves one of the categories of Container Loading Problems, object of study that belongs to Optimization, within the Operational Research. It’s considered the existence of multiple containers ofthe equal dimensionsthat promote the full loading of the availablecargoinindustrial transportation context. Thisload is composed ofstrongly heterogeneous assortment to the boxes, and allows rotation in any of the six possibilities, making the problem even more complex, and therefore less studied in the literature. A bibliographic review is also presented, containing an overview of the classifications of the problem and, in particular, an deepened study on genetic algorithms. The implementation of AGE-E was performed, and the computational results were compared with the best solutions already determined by the bibliography, demonstrating the potentialofAGE-E for future studies.
47

Optimering och visualisering av en beläggningskammare / Optimization and visualization of a coating chamber

Guo, Tjelvar, Johnsson, Daniel, Karlsson, Johan, Larsson, Rasmus, Luusua, Emil, Nordanskog, Axel, Zeijlon, Alexander, Örjehag, Erik January 2018 (has links)
Denna rapport behandlar kandidatprojektet Optily som utförts av 8 studenter på Tekniska högskolan vid Linköpings universitet. Hela processen från planering och utveckling till resultatet av den slutgiltiga produkten presenteras och diskuteras. Även erfarenheter som fångats upp av projektgruppen under denna process behandlas. Företaget Ionbond Sweden AB, som är kund i projektet, arbetar med ytbeläggning av rundskaftade föremål. För att underlätta planeringen av hur deras beläggningskammare ska packas har ett datorprogram kallat Optily utvecklats av projektgruppen. Detta har med framgång ökat effektiviteten i packningen av maskinerna vilket leder till ökad omsättning eftersom fler föremål kan köras tillsammans. Utöver ökad omsättning bidrar detta också till att hjälpa Ionbond Sweden AB att nå sina uppsatta miljömål. Programmet har även lyckats förbättra arbetssituationen för de anställda genom att på förhand visa hur maskinerna ska packas och vilka ordrar som då kommer få plats. Genom att integrera systemet med Ionbond Sweden AB:s nuvarande produktdatabas hanteras alla olika produkter som kan behöva ytbeläggas. Packningens utformning tas sedan fram genom att placera objekten med hjälp av en optimeringsalgoritm vilken når ett resultat som konsekvent är bättre än vad planeringsansvarig tidigare lyckats med. Resultatet av optimeringen visualiseras sedan med hjälp av en schematisk bild på hur objekten ska placeras i beläggningskammaren för att på bästa sätt utnyttja den tillgängliga volymen.
48

Agrégation de ressources avec contrainte de distance : applications aux plateformes de grande échelle.

Larchevêque, Hubert 27 September 2010 (has links) (PDF)
Durant cette thèse, nous avons introduit les problèmes de Bin Covering avec Contrainte de Distance (BCCD) et de Bin Packing avec Contrainte de Distance (BPCD), qui trouvent leur application dans les réseaux de grande échelle, tel Internet. L'étude de ces problèmes que nous effectuons dans des espaces métriques quelconques montre qu'il est impossible de travailler dans un tel cadre sans avoir recours à de l'augmentation de ressources, un procédé qui permet d'élaborer des algorithmes construisant des solutions moins contraintes que la solution optimale à laquelle elles sont comparées. En plus de résultats d'approximation intéressants, nous prouvons la difficulté de ces problèmes si ce procédé n'est pas utilisé. Par ailleurs, de nombreux outils ont pour objectif de plonger les grands réseaux qui nous intéressent dans des espaces métriques bien décrits. Nous avons alors étudié nos problèmes dans les espaces métriques générés par certains de ces outils, comme Vivaldi et Sequoia.
49

Metody řešení vybraných dopravních problémů a jejich implementace. / Methods for solving selected vehicle routing problems and their implementation.

Drobný, Michal January 2014 (has links)
Various types of transportation issues are a common practice. The issue may be approached mainly as the distribution of products from suppliers to consumers while minimising distribution costs. The difference of real transportation issues predominantly relates to the considered restrictions, such as capacities of vehicles and orders, time windows and other special distribution restrictions. Transportation issues were already defined by F.L. Hitchcock in 1941 and since then, a wide range of stochastic and non- determinist methods providing solutions to transportation issues have been developed. Nevertheless, introducing distribution restrictions in resolving real-life problems makes it difficult for such methods to be applied. This thesis provides a compilation of the well-known determinist methods that may be used to resolve transportation issues. The methods that are appropriate for resolving real issues are discussed in more detail. The solution procedure of the selected method is demonstrated using simple examples and the results are compared with the results of other methods. An analysis of the above methods is used to design and implement new methods to resolve real transportation issues, their results being compared with the methods provided by the commercial software product.
50

Uma abordagem heurística para o corte de itens irregulares em múltiplos recipientes / A heuristic approach for cutting irregular items in multiple containers

Mundim, Leandro Resende 25 March 2015 (has links)
Problemas de corte e empacotamento de itens irregulares são problemas que visam determinar um leiaute ótimo de objetos pequenos dentro de objetos maiores, a fim de atender a uma demanda. Estes problemas têm grande importância prática, já que surgem em vários tipos de indústria (como a têxtil, a de móveis e a de calçados). O problema estudado neste trabalho é o problema de corte de itens irregulares em recipientes. Os recipientes são delimitados e o objetivo é encontrar um leiaute dos objetos menores, sem sobreposição, dentro dos objetos maiores utilizando a menor quantidade de recipientes. Propomos um novo método de resolução para o problema. Nosso método é um algoritmo que gerencia um conjunto de heurísticas, de baixo nível, específicas para a resolução do problema com recipientes retangulares e irregulares. Recipientes irregulares são polígonos convexos e não convexos, que podem ser furados. As heurísticas desenvolvidas utilizam uma malha de pontos sobre a técnica de no-fit polygon para evitar a sobreposição dos itens e encontrar posições viáveis no recipiente retangular ou irregular. Os experimentos computacionais foram feitos para um grande conjunto de instâncias, de recipientes retangulares e irregulares. Os resultados demonstram a competitividade do método, que obtêm resultados bons e algumas soluções ótimas, em um tempo computacional aceitável. / Cutting and packing of irregular items are problems that aim to determine the optimum layout of small objects within larger objects (that we call bins), in order to meet a demand. These problems have great practical importance, since they emerge in various types of industry (such as textile, furniture and shoemaking). The problem studied in this work is the irregular bin packing problem. The bins are enclosed and the goal is to find a layout of items, without overlap, within the bins by using the minimum quantity of them. We propose a new method of resolution to this problem. Our method is an algorithm that manages a set of low-level heuristics, specific to solve the problem with rectangular bins and irregular bins. Irregular bins are convex and non-convex polygons, which may contain holes. The developed heuristics uses a mesh of points and the technique of no-fit polygon to avoid the overlapping of items and find feasible positions in rectangular or irregular bins. The computational experiments were performed for a large set of instances, using both rectangular and irregular bins. The results demonstrate the competitiveness of the method, which can get good results and some optimal solutions within an acceptable computational time.

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