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Miller, Andrew J. "Polyhedral approaches to capacitated lot-sizing problems." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/24284.
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Mahdieh, M. "Integrated capacitated lot sizing and scheduling problems in a flexible flow line." Thesis, University of the West of England, Bristol, 2013. http://eprints.uwe.ac.uk/21584/.
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The lot sizing and scheduling problem in a Flexible Flow Line (FFL) has extensive real-world applications in many industries. An FFL consists of several production stages in series with parallel machines at each stage. The decisions to be taken are the determination of production quantities (lots), machine assignments and production sequences (schedules) on each machine at each stage in an FFL. Lot sizing and scheduling problems are closely interrelated. Solving them separately and then coordinating their interdependencies is often ineffective. However due to their complexity, there is a lack of mathematical modelling and solution procedures in the literature to combine and jointly solve them. Up to now most research has been focused on combining lotsizing and scheduling for the single machine configuration, and research on other configurations like FFL is sparse. This thesis presents several mathematical models with practical assumptions and appropriate algorithms, along with experimental test problems, for simultaneously lotsizing and scheduling in FFL. This problem, called the ‘General Lot sizing and Scheduling Problem in a Flexible Flow Line’ (GLSP-FFL). The objective is to satisfy varying demand over a finite planning horizon with minimal inventory, backorder and production setup costs. The problem is complex as any product can be processed on any machine, but these have different processing rates and sequence-dependent setup times & costs. As a result, even finding a feasible solution of large problems in reasonable time is impossible. Therefore the heuristic solution procedure named Adaptive Simulated Annealing (ASA), with four well-designed initial solutions, is designed to solve GLSP-FFL. A further original contribution of this study is to design linear mixed-integer programming (MILP) formulations for this problem, incorporating all necessary features of setup carryovers, setup overlapping, non-triangular setup while allowing multiple lot production per periods, lot splitting and sequencing through ATSP-adaption based on a variety of subtour elimination.
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Darwish, Mohammed. "Lot-sizing and scheduling optimization using genetic algorithm." Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-17045.
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Simultaneous lot-sizing and scheduling problem is the problem to decide what products to be produced on which machine and in which order, as well as the quantity of each product. Problems of this type are hard to solve. Therefore, they were studied for years, and a considerable number of papers is published to solve different lotsizing and scheduling problems, specifically real-case problems. This work proposes a Real-Coded Genetic Algorithm (RCGA) with a new chromosome representation to solve a non-identical parallel machine capacitated lot-sizing and scheduling problem with sequence dependent setup times and costs, machine cost and backlogging. Such a problem can be found in real world production line at furniture manufacturer in Sweden. Backlogging is an important concept in this problem, and it is often ignored in the literature. This study implements three different types of crossover; one of them has been chosen based on numerical experiments. Four mutation operators have been combined together to allow the genetic algorithm to scan the search area and maintain genetic diversity. Other steps like initializing of the population and a reinitializing process have been designed carefully to achieve the best performance and to prevent the algorithm from trapped into the local optimum. The proposed algorithm is implemented and coded in MATLAB and tested for a set of standard medium to large-size problems taken from the literature. A variety of problems were solved to measure the impact of different characteristics of problems such as the number of periods, machines, and products on the quality of the solution provided by the proposed RCGA. To evaluate the performance of the proposed algorithm, the average deviation from the lower bound and runtime for the proposed RCGA are compared with three other algorithms from the literature. The results show that, in addition to its high computational speed, the proposed RCGA outperforms the other algorithms for non-identical parallel machine problems, while it is outperformed by the other algorithms for problems with the more identical parallel machine. The results show that the different characteristics of problem instances, like increasing setup cost, and size of the problem influence the quality of the solutions provided by the proposed RCGA negatively.
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Anemyr, Mattias. "Optimization of Production Scheduling at IKEA Industry Hultsfred." Thesis, Linköpings universitet, Kommunikations- och transportsystem, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-167145.
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IKEA Industry has factories in several locations where one location is in Hultsfred, Småland. IKEA Industry Hultsfred produces IKEA:s wardrobe collection PAX. In 2018, 2.8 million wardrobes were manufactured in Hultsfred. This thesis covers the subject of constructing and developing an optimization model which has the same characteristics as the plinth production at IKEA Industry Hultsfred. This means that the optimization model must consider production sequence; the setup time is different depending on which products that have been produced in the machine earlier. The thesis also covers to investigate how much time that is necessary to produce the plinths to Hultsfred, Portugal, and Germany under different circumstances. This thesis also balances inventory levels and setup time. I.e., how the inventory levels are changed if more emphasis is put into minimizing setup time, and the other way around. The results show that lower inventory levels and setup times are achievable over seven days if the production planning technique is changed.
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Baldo, Tamara Angélica. "Geração de colunas para o problema de dimensionamento de lotes de produção com limitações de capacidade." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-28042010-141209/.
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O problema de dimensionamento de lotes com restrições de capacidade (CLSP) consiste em determinar um plano de produção que satisfaça a demanda requerida, respeitando as limitações de capacidade, com o menor custo possível, ou seja, minimizando os custos de produção, estocagem e preparação de máquina. Encontrar uma solução factível para o CLSP, considerando tempo de preparação de máquina, é NP-completo. Nesta dissertação, para a resolução do CLSP, utiliza-se a decomposição de Dantzig-Wolfe e o procedimento de geração de colunas, encontrando bons limitantes inferiores. Duas diferentes estratégias de decomposição são exploradas, decomposição por itens e períodos. Para a obtenção de uma solução inteira para o problema (limitante superior) foram exploradas heurísticas lagrangianas, onde a solução inicial para as heurísticas provém da geração de colunas. Os limitantes obtidos podem ser utilizados em métodos exatos, como por exemplo, em algoritmos do tipo branch-and-price. Experimentos computacionais, baseados em exemplares gerados aleatoriamente, foram realizados e os resultados analisados, as variações dos parâmetros das instâncias foram sugeridas na literaturaThe Capacitated Lot Sizing Problem (CLSP) consists in determining a production plan such that all demands are met and the total costs of production, inventory and setup are minimized. Since the problem to find a feasible solution to the CLSP with setup times is NP-complete, large problem instances have been solved by heuristic methods. In this dissertation, we are particularly concerned in using the methodology of Dantzig-Wolfe decomposition and column generation to generate good bounds to the CLSP with setup times and costs. Here, we analyse two types of decomposition which are based on items and time periods (lower bound) and some lagrangian-based heuristics (upper bound). Numerical results based on randomly generated intances suggest that highquality lower bounds are obtained by column generation algorithms, such as well as upper bounds by heuristics. These bounds are useful in exact solution methods, such as branch-and-price algorithms
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Leung, Janny M. Y., Thomas L. Magnanti, and Rita Vachani. "Facets and Algorithms for Capacitated Lot Sizing." Massachusetts Institute of Technology, Operations Research Center, 1987. http://hdl.handle.net/1721.1/5210.
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The dynamic economic lot sizing model, which lies at the core of numerous production planning applications, is one of the most highly studied models in all of operations research. And yet, capacitated multi-item versions of this problem remain computationally elusive. We study the polyhedral structure of an integer programming formulation of a single-item capacitated version of this problem, and use these results to develop solution methods for multi-item applications. In particular, we introduce a set of valid inequalities for the problem and show that they define facets of the underlying integer programming polyhedron. Computational results on several single and multiple product examples show that these inequalities can be used quite effectively to develop an efficient cutting plane/branch and bound procedure. Moreover, our results show that in many instances adding certain of these inequalities a priori to the problem formulation, and avoiding the generation of cutting planes, can be equally effective.
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Önal, Mehmet. "Extensions to the economic lot sizing problem." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0024781.
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Trouiller, Cyril. "Capacitated multi-item lot sizing with an interior point cutting plane algorithm." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23429.
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The capacitated multi-item lot sizing problem is a model which aims at scheduling production of several products over a finite number of periods, while minimizing production costs, holding inventory costs and setup costs subject to demand and capacity constraints. These costs may vary for each product and each period and are all linear. Our model includes setup times for each product.We compare two approaches: a classic Lagrangean relaxation of the capacity constraints and a Lagrangean decomposition by variable splitting. In both cases, the Lagrangean multipliers are updated with an interior point cutting plane technique. The results show: (1) The superiority of the interior point method over the commonly used subgradient optimization in terms of accuracy at termination, number of iterations and ease of utilization. (2) The better quality of the bounds obtained by the Lagrangean decomposition by variable splitting over the Lagrangean relaxation.
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Huaccha, Neyra Jackeline del Carmen [UNESP]. "Estudos em problemas de dimesionamento de lotes com preparações carryover e crossover." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/149955.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Os problemas de dimensionamento de lotes consistem em determinar a quantidade de itens que devem ser produzidos em todos os períodos de um horizonte de planejamento. Em geral, são considerados custos de produção, preparação de máquina e de manutenção de estoque. Neste trabalho estuda-se uma extensão do problema de dimensionamento de lotes com restrição de capacidade que considera tempos de preparação, preparação carryover e crossover, em que se tem uma única máquina, único estágio, multi-itens e big-bucket (CLSP-SCC). Novas formulações para o CLSP-SCC são apresentadas e evitam a necessidade de definir novas variáveis binárias para modelar a preparação crossover. Também são propostas restrições de quebra de simetria para formulações propostas na literatura. São provadas as relações teóricas que existem entre cada uma destas formulações estudadas. Além disso, é proposta uma heurística híbrida que combina as heurísticas Relax-and-Fix e Fix-and-Optimize (RF-FO), em que a heurística Relax-and-Fix é usada para obter uma solução inicial e a heurística Fix-and-Optimize melhora essa solução. Por fim, apresentam-se os resultados computacionais e conclui-se que os resultados obtidos melhoram significativamente quando comparam-se a formulação clássica com as formulações sem preparação carryover. Compara-se também os resultados da heurística com os do pacote computacional CPLEX e, quando ambos são limitados ao mesmo tempo computacional, a heurística RF-FO obtém melhores resultados.
Lot-Sizing Problems consist of determining the quantity of items to be produced in each period of a planning horizon. In general, production, setup and inventory costs are considered. In this work an extension of the Capacitated Lot-Sizing Problem is studied, which considers setup times, Setup Carryover and Setup Crossover, single machine, single level, multi items, multi periods and big-bucket (CLSP-SCC). New formulations to the CLSP-SCC are presented and avoid the necessity of defining new extra binary variables to model the setup crossover. Furthermore, symmetry breaking constraints are proposed for formulations from the literature. The theoretical relations between the studied formulations are proved. A Relax-and-Fix and Fixand-Optimize (RF-FO) hybrid heuristic is proposed, in which the Relax-and-Fix helps to find an initial solution and the Fix-and-Optimize improves it. Computational results are presented and the obtained results improve significantly when comparing the classical formulation with the formulation without setup carryover. Finally, the results obtained by the RF-FO heuristic and the computational package CPLEX are compared and, when they both are limited to the same computational time, the RF-FO heuristic obtains better results.
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Van, Hoesel Stan, and Albert Wagelmans. "Sensitivity Analysis of the Economic Lot-Sizing Problem." Massachusetts Institute of Technology, Operations Research Center, 1990. http://hdl.handle.net/1721.1/5146.
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In this paper we study sensitivity analysis of the uncapacitated single level economic lot-sizing problem, which was introduced by Wagner and Whitin about thirty years ago. In particular we are concerned with the computation of the maximal ranges in which the numerical problem parameters may vary individually, such that a solution already obtained remains optimal. Only recently it was discovered that faster algorithms than the Wagner-Whitin algorithm exist to solve the economic lot-sizing problem. Moreover, these algorithms reveal that the problem has more structure than was recognized so far. When performing the sensitivity analysis we exploit these newly obtained insights.
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Heuvel, Wilco van den. "The economic lot-sizing problem: new results and extensions." [Rotterdam] : Rotterdam : Erasmus Research Institute of Management (ERIM), Erasmus University Rotterdam ; Erasmus University [Host], 2006. http://hdl.handle.net/1765/8193.
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Staggemeier, Andrea Toniolo. "Metaheuristics in a production lot-sizing and scheduling problem." Thesis, University of the West of England, Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501090.
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The single-stage simultaneous lot sizing and scheduling problem was the object of study in this work. The problem aims to minimize the total inventory and backlog costs associated with producing N products on M parallel machines over T time-period. This thesis presented an extensive literature review on the differences found when modelling and implementing lot sizing and scheduling systems. We observed several studies used metaheuristics successfully to address large instances of these problems achieving near, and sometimes, optimal results. However, little has been found to demonstrate the capabilities of Evolutionary Algorithms in this field. A description of the methodology used to s problem : is given in terms of a Hybrid Evolutionary Algorithm which represents the problem using two novel ideas, i.e., sets of products are modelled as alleles of the solution encoded, and the use of a decoder process performing a Linear Programming, guides the solution towards overall optimality.
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Kaya, Melike. "A Heuristic Approach For Profit Oriented Disassembly Lot-sizing Problem." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613039/index.pdf.
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In this thesis, we work on adisassembly lot-sizing problem for multiple products with parts commonality,i.e., general product structure. We assume that supply of discarded products is infinite. When a product (or a subassembly) is disassembled, all its immediate child items are obtained,i.e., complete disassembly case.Intermediate and leaf items obtained are demandedbyexternal suppliers or remanufacturers. The maximum possible salesfor each intermediate and leaf item are known.Sales of the intermediate and leaf items are the revenue sources. The discarded products are purchased ata unit purchasing cost. The disassembly operation incurs a fixed and a variable disassembly cost. Due to this cost structure, intermediate and leaf items can be stocked incurring an inventory holding cost. We develop an integer programming formulation to determine the time and quantity of the discarded products to be purchasedthetime and quantity of the discarded products and the intermediateitemsto be disassembled
and the time and quantity of intermediate and leaf items to be soldin order tomaximizethe total profit over a finite planning horizon. We state that ourproblem is NP-hard by refering the study of Kim et. al. (2009). We propose a heuristic solution approach that solves the problem in a reasonable computational time and generates near optimal solutions. The solution approach is based on the idea of sequentially solving a relaxed version of the problem and one-period integer programming models.In a computational study, the performance of the heuristic approach is assessed for a number ofrandomly generated problem instances.The results of the computational study show that the solutions of the heuristic approacharevery close to the optimal and the best feasible solutions obtained within the time limit.
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Shen, Xueying. "Complex lot Sizing problem with parallel machines and setup carryover." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLED057/document.
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Dans cette thèse, nous étudions deux problèmes de planification de production motivés par des applications du monde réel. Tout d'abord, un problème de planification de production pour un projet de fabrication de vêtements est étudié et un outil d'optimisation est développé pour le résoudre. Deuxièmement, une version restreinte du problème de dimensionnement du lot de capacité avec des configurations dépendantes de la séquence est explorée. Diverses formulations mathématiques sont développées et une analyse de complexité est effectuée pour donner une première analyse du problèmeIn this thesis, we study two production planning problems motivated by challenging real-world applications. First, a production planning problem for an apparel manufacturing project is studied and an optimization tool is developed to tackle it. Second, a restricted version of the capacitated lot sizing problem with sequence dependent setups is explored. Various mathematical formulations are developed and complexity analysis is performed to offer a first glance to the problem
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Koclar, Ayse. "The General Lot Sizing And Scheduling Problem With Sequence Dependent Changeovers." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606117/index.pdf.
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In this study, we consider the General Lot Sizing and Scheduling Problem in single level capacitated environments with sequence dependent item changeovers. Process industries may be regarded as suitable application areas of the problem. The focus on capacity utilization and intensively time consuming changeovers necessitate the integration of lot sizing and sequencing decisions in the production plan.
We present a mathematical model which captures the essence of cases in the most generic and realistic setting of the problem. We discuss the impact and validity of some of the assumptions commonly encountered in the related literature. We also represent the problem using an alternative formulation and attempt to enhance the formulations with the use of some additional inequalities. Finally, we develop a heuristic by restricting the number of possible changeovers. Computational results are discussed.
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Narayanan, Arunachalam. "Improved formulations, heuristics and metaheuristics for the dynamic demand coordinated lot-sizing problem." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1802.
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Zhai, Zhongping. "The Order Selection and Lot Sizing Problem in the Make-to-Order Environment." FIU Digital Commons, 2011. http://digitalcommons.fiu.edu/etd/364.
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This research is motivated by the need for considering lot sizing while accepting customer orders in a make-to-order (MTO) environment, in which each customer order must be delivered by its due date. Job shop is the typical operation model used in an MTO operation, where the production planner must make three concurrent decisions; they are order selection, lot size, and job schedule. These decisions are usually treated separately in the literature and are mostly led to heuristic solutions.
The first phase of the study is focused on a formal definition of the problem. Mathematical programming techniques are applied to modeling this problem in terms of its objective, decision variables, and constraints. A commercial solver, CPLEX is applied to solve the resulting mixed-integer linear programming model with small instances to validate the mathematical formulation. The computational result shows it is not practical for solving problems of industrial size, using a commercial solver.
The second phase of this study is focused on development of an effective solution approach to this problem of large scale. The proposed solution approach is an iterative process involving three sequential decision steps of order selection, lot sizing, and lot scheduling. A range of simple sequencing rules are identified for each of the three sub-problems. Using computer simulation as the tool, an experiment is designed to evaluate their performance against a set of system parameters.
For order selection, the proposed weighted most profit rule performs the best. The shifting bottleneck and the earliest operation finish time both are the best scheduling rules. For lot sizing, the proposed minimum cost increase heuristic, based on the Dixon-Silver method performs the best, when the demand-to-capacity ratio at the bottleneck machine is high. The proposed minimum cost heuristic, based on the Wagner-Whitin algorithm is the best lot-sizing heuristic for shops of a low demand-to-capacity ratio. The proposed heuristic is applied to an industrial case to further evaluate its performance. The result shows it can improve an average of total profit by 16.62%. This research contributes to the production planning research community with a complete mathematical definition of the problem and an effective solution approach to solving the problem of industry scale.
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Löhndorf, Nils, and Stefan Minner. "Simulation Optimization for the Stochastic Economic Lot Scheduling Problem." Taylor and Francis, 2013. http://dx.doi.org/10.1080/0740817X.2012.662310.
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We study simulation optimization methods for the stochastic economic lot scheduling problem. In contrast to
prior research, we focus on methods that treat this problem as a black box. Based on a large-scale numerical
study, we compare approximate dynamic programming with a global search for parameters of simple control
policies. We propose two value function approximation schemes based on linear combinations of piecewise-
constant functions as well as control policies that can be described by a small set of parameters. While
approximate value iteration worked well for small problems with three products, it was clearly outperformed
by the global policy search as soon as problem size increased. The most reliable choice in our study was a
globally optimized fixed-cycle policy. An additional analysis of the response surface of model parameters on
optimal average cost revealed that the cost effect of product diversity was negligible. (authors' abstract)
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Liu, Xin. "Heuristic strategies for the single-item lot-sizing problem with convex variable production cost." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B3642917X.
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Liu, Xin, and 劉忻. "Heuristic strategies for the single-item lot-sizing problem with convex variable production cost." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B3642917X.
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Brodkorb, Daniel Verfasser], Wilhelm [Akademischer Betreuer] [Dangelmaier, and Leena [Akademischer Betreuer] Suhl. "Two-level capacitated lot sizing in production control to guarantee availability, considering multidimensional restrictions / Daniel Brodkorb. Betreuer: Wilhelm Dangelmaier ; Leena Suhl." Paderborn : Universitätsbibliothek, 2011. http://d-nb.info/1033763985/34.
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Löhndorf, Nils, Manuel Riel, and Stefan Minner. "Simulation Optimization for the Stochastic Economic Lot Scheduling Problem with Sequence-Dependent Setup Times." Elsevier, 2014. http://dx.doi.org/10.1016/j.ijpe.2014.05.006.
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We consider the stochastic economic lot scheduling problem (SELSP) with lost sales and random demand,
where switching between products is subject to sequence-dependent setup times. We propose a solution
based on simulation optimization using an iterative two-step procedure which combines global policy search
with local search heuristics for the traveling salesman sequencing subproblem. To optimize the production
cycle, we compare two criteria: minimizing total setup times and evenly distributing setups to obtain a more
regular production cycle. Based on a numerical study, we find that a policy with a balanced production cycle
leads to lower cost than other policies with unbalanced cycles. (authors' abstract)
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Gicquel, Céline. "MIP models and exact methods for the Discrete Lot-sizing and Scheduling Problem with sequence-dependent changeover costs and times." Phd thesis, Ecole Centrale Paris, 2008. http://tel.archives-ouvertes.fr/tel-00375964.
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Le dimensionnement des lots de production est une des nombreuses activités survenant dans le cadre de la planification de production. Il a pour objet de déterminer quand et combien produire de façon à réaliser le meilleur compromis possible entre la minimisation des coûts liés à la production (coûts fixes de reconfiguration de la ressource, coûts de stockage...) et la satisfaction de la demande des clients Nous nous intéressons ici un problème de planification de production par lots connu sous le nom de "Discrete Lot-sizing and Scheduling Problem" ou "DLSP". Plus précisément, nous étudions plusieurs variantes de ce problème dans lesquelles les coûts et/ou les temps de changement de produits sur la ressource sont dépendant de la séquence et nous proposons diverses extensions d'une méthode disponible dans la littérature pour la résolution exacte du problème mono-niveau, mono-ressource. Nos contributions portent à la fois sur la modélisation du problème et sur l'implémentation de méthodes efficaces de résolution. En ce qui concerne la modélisation, nous étudions l'intégration de divers aspects opérationnels dans le modèle de base afin d'en améliorer la pertinence industrielle. Ainsi nous considérons les extensions suivantes : la prise en compte d'une structure de produits "multi-attributs" qui permet de diminuer la taille du problème d'optimisation à résoudre, l'intégration de temps de changement positifs afin de mieux modéliser la perte de production causée par une reconfiguration de la ressource et la présence de plusieurs ressources parallèles dont la production doit être planifiée simultanément. En ce qui concerne la résolution du problème, nous présentons pour chacune des extensions du modèle de base une approche de résolution visant à fournir des solutions optimales exactes. En général, les résultats de nos expériences numériques montrent l'utilité pratique de ces algorithmes pour la résolution d'instances de moyenne et grande taille en des temps de calcul compatibles avec une application industrielle
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Spiekermann, Nils Verfasser], Arie Marinus [Akademischer Betreuer] Koster, and Christina [Akademischer Betreuer] [Büsing. "Novel variants and applications of the single-item lot-sizing problem / Nils Spiekermann ; Arie Marinus Koster, Christina Maria Katharina Büsing." Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/1193429587/34.
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Spiekermann, Nils [Verfasser], Arie Marinus Akademischer Betreuer] Koster, and Christina [Akademischer Betreuer] [Büsing. "Novel variants and applications of the single-item lot-sizing problem / Nils Spiekermann ; Arie Marinus Koster, Christina Maria Katharina Büsing." Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/1193429587/34.
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Leandrin, Matheus Artioli. "Problema de redimensionamento de lotes para máquinas paralelas em ambientes de usinagem /." Bauru, 2019. http://hdl.handle.net/11449/183302.
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Orientador: Adriana Cristina Cherri NicolaBanca: Silvio Alexandre de Araujo
Banca: Sonia Cristina Poltroniere Silva
Resumo: Este trabalho aborda o Problema de Redimensionamento de Lotes (PRL) capacitado, com múltiplos produtos e máquinas paralelas. O redimensionamento de lotes é uma variação do problema de dimensionamento de lotes que pode ser identificado em sistemas produtivos com elevada taxa de interrupções, como quebras, refugos, entre outros, fazendo com que o plano de produção seja prejudicado, necessitando de atualizações a medida que ocorrem as interrupções. São considerados três parâmetros de interrupção: manutenção corretiva, mão de obra insuficiente e indisponibilidade de matéria-prima. É permitido o atendimento da demanda nos períodos com atrasos e utilização de hora extra. O problema tem por objetivo minimizar os custos de preparação, estoque, atraso e hora extra. Baseado em um modelo matemático proposto na literatura para resolver problemas de dimensionamento de lotes, um modelo matemático para representar o PRL foi proposto. O PRL foi formulado como um problema de programação linear inteira mista (PLIM) e resolvido através do método exato branch and bound. Testes computacionais foram realizados com exemplares adaptados da literatura e abrangem os três parâmetros de interrupção
Abstract: This work approaches the capacitated Lot Resizing Problem (LRP) with multi-products and parallel machines. The lot resizing problem is a lot sizing problem variation which can be identified in productive systems with high rate of interruptions, as breaks, refuse, and others, impairing the planning production and making update needed as soon as interruptions happens. Three parameters for interruption were considered: corrective maintenance, insufficient man power and unavailability of raw material. Demand can be performed with back-orders and overtime requests. This work has the objective of minimize inventory holding costs, back-orders, setup and overtime costs. Based on a mathematical model proposed in the literature to solve the lot sizing problem, a mathematical model to represent the LRP was proposed. The LRP was formulated as a mixed integer problem and solved by branch and bound exact method. Computational experiments were performed with adapted literature instances embracing the three parameters of interruption
Mestre
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Solyali, Oguz. "One-warehouse Multi-retailer Problem Under Inventory Control And Transportation Policies." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610239/index.pdf.
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We consider a one-warehouse multi-retailer system where the warehouse orders or receives from its supplier and replenishes multiple retailers with direct shipping or multi-stop routing over a finite time horizon. The warehouse has the knowledge of external (deterministic) demands at the retailers and manages their inventories while ensuring no stock-out. We consider two problems with direct shipping policy and two problems with routing policy. For the direct shipping policy, the problem is to determine the optimal replenishments for the warehouse and retailers such that the system-wide costs are minimized. In one problem, the warehouse decides about how much and when to ship to the retailers while in the other problem, inventory level of the retailer has to be raised up to a predetermined level whenever replenished. We propose strong mixed integer programming formulations for these problems. Computational experiments show that our formulations are better than their competitors and are very successful in solving the problems to optimality. For the routing policy, the problem is to decide on when and in what sequence to visit the retailers and how much to ship to a retailer so as to minimize system-wide costs. In one problem, the warehouse receives given amounts from its supplier while in the other the warehouse decides on its own replenishments. We propose branch-and-cut algorithms and heuristics based on strong formulations for both problems. Computational results reveal that our procedures perform better than their competitors in the literature for both problems.
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Gaillard, de Saint Germain Etienne. "Arbitrer coût et flexibilité dans la Supply Chain." Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC1113/document.
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Cette thèse développe des méthodes d'optimisation pour la gestion de la Supply Chain et a pour thème central la flexibilité définie comme la capacité à fournir un service ou un produit au consommateur dans un environnement incertain. La recherche a été menée dans le cadre d'un partenariat entre Argon Consulting, une société indépendante de conseil en Supply Chain et l'École des Ponts ParisTech. Dans cette thèse, nous développons trois sujets rencontrés par Argon Consulting et ses clients et qui correspondent à trois différents niveaux de décision (long terme, moyen terme et court terme).Lorsque les entreprises élargissent leur portefeuille de produits, elles doivent décider dans quelles usines produire chaque article. Il s'agit d'une décision à long terme, car une fois qu'elle est prise, elle ne peut être facilement modifiée. Plus qu'un problème d'affectation où un article est produit par une seule usine, ce problème consiste à décider si certains articles doivent être produits par plusieurs usines et par lesquelles. Cette interrogation est motivée par la grande incertitude de la demande. En effet, pour satisfaire la demande, l'affectation doit pouvoir équilibrer la charge de travail entre les usines. Nous appelons ce problème le multi-sourcing de la production. Comme il ne s'agit pas d'un problème récurrent, il est essentiel de tenir compte du risque au moment de décider le niveau de multi-sourcing. Nous proposons un modèle générique qui inclut les contraintes techniques du problème et une contrainte d'aversion au risque basée sur des mesures de risque issues de la théorie financière. Nous développons un algorithme et une heuristique basés sur les outils standards de la Recherche Opérationnelle et de l'Optimisation Stochastique pour résoudre le problème du multi-sourcing et nous testons leur efficacité sur des données réelles.Avant de planifier la production, certains indicateurs macroscopiques doivent être décidés à horizon moyen terme tels la quantité de matières premières à commander ou la taille des lots produits. Certaines entreprises utilisent des modèles de stock en temps continu, mais ces modèles reposent souvent sur un compromis entre les coûts de stock et les coûts de lancement. Ces derniers sont des coûts fixes payés au lancement de la production et sont difficiles à estimer en pratique. En revanche, à horizon moyen terme, la flexibilité des moyens de production est déjà fixée et les entreprises estiment facilement le nombre maximal de lancements. Poussés par cette observation, nous proposons des extensions de certains modèles classiques de stock en temps continu, sans coût de lancement et avec une limite sur le nombre d'installations. Nous avons utilisé les outils standard de l'Optimisation Continue pour calculer les indicateurs macroscopiques optimaux.Enfin, la planification de la production est une décision à court terme qui consiste à décider quels articles doivent être produits par la ligne de production pendant la période en cours. Ce problème appartient à la classe bien étudiée des problèmes de Lot-Sizing. Comme pour les décisions à moyen terme, ces problèmes reposent souvent sur un compromis entre les coûts de stock et les coûts de lancement. Fondant notre modèle sur ces considérations industrielles, nous gardons le même point de vue (aucun coût de lancement et une borne supérieure sur le nombre de lancement) et proposons un nouveau modèle.Bien qu'il s'agisse de décisions à court terme, les décisions de production doivent tenir compte de la demande future, qui demeure incertaine. Nous résolvons notre problème de planification de la production à l'aide d'outils standard de Recherche Opérationnelle et d'Optimisation Stochastique, nous testons l'efficacité sur des données réelles et nous la comparons aux heuristiques utilisées par les clients d'Argon ConsultingThis thesis develops optimization methods for Supply Chain Management and is focused on the flexibility defined as the ability to deliver a service or a product to a costumer in an uncertain environment. The research was conducted throughout a partnership between Argon Consulting, which is an independent consulting firm in Supply Chain Operations and the École des Ponts ParisTech. In this thesis, we explore three topics that are encountered by Argon Consulting and its clients and that correspond to three different levels of decision (long-term, mid-term and short-term).When companies expand their product portfolio, they must decide in which plants to produce each item. This is a long-term decision since once it is decided, it cannot be easily changed. More than a assignment problem where one item is produced by a single plant, this problem consists in deciding if some items should be produced on several plants and by which plants. This is motivated by a highly uncertain demand. So, in order to satisfy the demand, the assignment must be able to balance the workload between plants. We call this problem the multi-sourcing of production. Since it is not a repeated problem, it is essential to take into account the risk when making the multi-sourcing decision. We propose a generic model that includes the technical constraints of the assignment and a risk-averse constraint based on risk measures from financial theory. We develop an algorithm and a heuristic based on standard tools from Operations Research and Stochastic Optimization to solve the multi-sourcing problem and we test their efficiency on real datasets.Before planning the production, some macroscopic indicators must be decided at mid-term level such as the quantity of raw materials to order or the size of produced lots. Continuous-time inventory models are used by some companies but these models often rely on a trade-off between holding costs and setups costs. These latters are fixed costs paid when production is launched and are hard to estimate in practice. On the other hand, at mid-term level, flexibility of the means of production is already fixed and companies easily estimate the maximal number of setups. Motivated by this observation, we propose extensions of some classical continuous-time inventory models with no setup costs and with a bound on the number of setups. We used standard tools from Continuous Optimization to compute the optimal macroscopic indicators.Finally, planning the production is a short-term decision consisting in deciding which items must be produced by the assembly line during the current period. This problem belongs to the well-studied class of Lot-Sizing Problems. As for mid-term decisions, these problems often rely on a trade-off between holding and setup costs. Basing our model on industrial considerations, we keep the same point of view (no setup cost and a bound on the number of setups) and propose a new model. Although these are short-term decisions, production decisions must take future demand into account, which remains uncertain. We solve our production planning problem using standard tools from Operations Research and Stochastic Optimization, test the efficiency on real datasets, and compare it to heuristics used by Argon Consulting's clients
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Christofoletti, Maurício Móz. "O problema integrado de dimensionamento de lotes e corte de estoque em uma indústria de colchões /." Bauru, 2018. http://hdl.handle.net/11449/180418.
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Orientador: Silvio Alexandre de AraujoCoorientadora: Adriana Cristina Cherri
Banca: Sonia Cristina Poltrooniere Silva
Banca: Roberto Fernandes Tavares Neto
Resumo: Dois problemas fundamentais surgem no planejamento da produção de muitos processos produtivos: o problema de dimensionamento de lotes e o problema de corte de estoque. Geralmente, as empresas tratam estes problemas separadamente, porém, ao considerá-los de maneira integrada, é possível obter melhores resultados. Neste trabalho, investiga-se o problema integrado de dimensionamento de lotes e corte de estoque tridimensional aplicado a uma indústria de colchões, visando à redução de custos e desperdícios. É proposto um modelo matemático de programação inteira mista para a resolução do problema. Testes computacionais com base em dados coletados em uma indústria do setor foram realizados, permitindo comparar as soluções obtidas pelo modelo e as soluções adotadas pela indústria. Testes adicionais foram realizados com dados aleatórios, a fim de avaliar o comportamento do modelo para diferentes casos. Os resultados indicam que o modelo apresenta um bom desempenho, reduzindo os custos da função objetivo para diferentes conjuntos de testes. Com base nos resultados, algumas direções interessantes podem ser exploradas pela indústria, como por exemplo, ao aumentar o número de padrões de corte, aumenta-se o número de combinações possíveis para o corte, resultando em melhor aproveitamento de material e redução nos custos.
Abstract: Two fundamental problems arise in the production planning of many productive processes: the lot-sizing problem and the cutting stock problem. Generally, companies deal with these problems separately, but by considering them in an integrated way, it is possible to obtain better results. In this paper, the integrated lot-sizing and three-dimensional cutting stock problem applied to a mattress industry is investigated, aiming at reducing costs and waste. It is proposed a mathematical model of mixed integer programming for the problem resolution. Computational tests based on data collected in an industry of the sector were carried out, allowing to compare the solutions obtained by the model and the solutions adopted by the industry. Additional tests were performed with random data in order to evaluate the behaviour of the model for different cases. The results indicate that the model performs well, reducing the objective function costs for different sets of tests. Based on the results, some interesting directions can be explored by the industry, for example, by increasing the number of cutting patterns, the number of possible combinations for cutting is increased, resulting in better material utilization and reduction in costs.
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Charnprasitphon, Aphiwat. "Modeling and analysis of the batch production scheduling problem for perishable products with setup times." Diss., Available online, Georgia Institute of Technology, 2007, 2007. http://etd.gatech.edu/theses/available/etd-01102007-183154/.
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Thesis (Ph. D.)--Industrial and Systems Engineering, Georgia Institute of Technology, 2007.Dr. Faiz Al-Khayyal, Committee Co-Chair ; Dr. Paul M. Griffin, Committee Co-Chair ; Dr. Earl Barnes, Committee Member ; Dr. Jye-Chyi Lu, Committee Member ; Dr. John Elton, Committee Member.
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Furlan, Marcos Mansano. "Métodos heurísticos para o problema de dimensionamento de lotes multiestágio com limitação de capacidade." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-16052011-162401/.
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O problema de dimensionamento de lotes determina um plano de produção que apoia às tomadas de decisões, a médio prazo, em meios industriais. Este plano de produção indica as quantidades de cada item que devem ser produzidas em cada período do horizonte de planejamento, de acordo com um objetivo dado e satisfazendo a demanda dos clientes. Diversos métodos de solução foram propostas na literatura, considerando a dificuldade de solução de algumas classes de problemas e a necessidade de métodos que gerem soluções de alta qualidade em um tempo computacional adequado. Neste trabalho, abordamos heurísticas baseadas na formulação matemática (LP-and-fix, relax-and-fix e fix-and-optimize), uma metaheurística (algoritmo de abelhas) e dois métodos híbridos, utilizados na solução de dois problemas distintos de dimensionamento de lotes multiestá- gio com limitação de capacidade. Consideramos também, a utilização de três formulações da literatura, para verificar a influência de cada uma sobre as abordagens de solução verificadas. Os resultados computacionais demonstraram que os métodos baseados na formulação matemática do problema se mostraram eficientes, mas limitados normalmente a ótimos locais, enquanto os métodos híbridos puderam superar estes ótimos locais, utilizando conceitos da metaheurística algoritmo de abelhas para isto. Além disso, pudemos verificar a influência de uma formulação \"forte\" sobre as soluções geradas pelas abordagens de solução, demonstrando que métodos baseados em relaxação linear conseguem obter maiores vantagens deste tipo de formulação, mas outras abordagens podem ou não obter estas vantagens, dependendo do problema abordadoThe lot-sizing problem determines a production plan, which supports the decision making, in the medium term, at the industrial environment. This production plan indicates the amounts of each item to be produced in each period of the planning horizon, according to a given objective and satisfying customer\'s demand. Diverse solution methods have been proposed in the literature, considering the difficulty of solving some problem classes and the need of methods to generate solutions quickly. In this work, we develop matheuristics (LP-and-fix, relax-and-fix and fix-and-optimize), one metaheuristic (bees algorithm) and two hybrid methods, used to solve two different multilevel capacitated lot-sizing problems. We also consider the use of three different formulations of the literature to verify the influence of each one on the solutions approaches. The computational results show that the matheuristics proved to be efficient, but usually limited to local optima, while the hybrid methods could escape from these local optima, using concepts of bees algorithm to do this. Additionally, we test the effect of a tight formulation on the solutions approaches, demonstrating that LP-based heuristics can obtain further advantages from this type of formulation, but other approaches can take these advantages, depending on the problem addressed
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Defalque, Cristiane Maria. "Estatégias para incorporação das deçisões de sequenciamento em um problema integrado de produção de bebidas /." São José do Rio Preto : [s.n.], 2010. http://hdl.handle.net/11449/94219.
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Orientador: Maria do Socorro Nogueira RangelBanca: Deisemara Ferreira
Banca: Silvio Alexandre Araujo
Resumo: Neste trabalho, propomos um modelo integrado de dimensionamento de lotes e programação da produção para uma fábrica de refrigerantes de pequeno porte denominado P1S1MTS. Neste modelo, as decisões de dimensionamento foram baseadas no modelo P1S1M encontrado na literatura, formulado com base no modelo GLSP. As decisões de sequenciamento foram modeladas utilizando restrições do problema do caixeiro viajante assimétrico. Para validação do modelo proposto e comparação entre os modelos P1S1MTS e P1S1M foram feitos testes computacionais com exemplares ilustrativos. Foram realizados também testes com exemplares baseados em dados reais da fábrica de refrigerantes e exemplares gerados aleatoriamente. Os testes foram resolvidos pelo método Branch-and-Cut incluído no pacote computacional CPLEX 10.0. Notamos que com algumas modificações, é possível que ambos os modelos retratem a mesma situação. A partir destas modificações e com os resultados obtidos, concluímos que a resolução de exempalres do modelo P1S1MTS apresentou um tempo de execução computacioanl menor que a resolução de exemplares do modelo P1S1M gerados com os mesmos dados.
Abstract: In this work we propose a lot sizing and scheduling model, P1S1MTS, for a smallscale soft drink plant. In this model, the lot sising decisions were based on the P1s!m model found in the literaure. To model the scheduling decisions constraints of the asynmetric traveling salesman problem are used. For the validation of the proposed model and a comparison between the P1S1MTS and the P1S1M models computational tests were executed with illustratuve examples. Tests were also executed with examples based on real data and randomly generated instances. Tests were also executed with examples based on real data and randomly in the software CPLEX 10.0. The results showed taht, with some minor modifications, it is possible that both models depict same situation. From the results obtained we concluded that the P1s!MTS model presented a computational time performance better than the P1S1M model.
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Carretero, Michelli Maldonado [UNESP]. "Formulações fortes para o problema integrado de dimensionamento e sequenciamento da produção." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/94207.
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Em alguns setores, o planejamento da produção envolve dois aspectos: o dimensionamento do tamanho dos lotes e a programação da produção (sequenciamento dos lotes). O primeiro problema consiste em determinar o tamanho dos lotes de produção de cada item a ser produzido em uma ou mais máquinas em cada período ao longo de um horizonte de planejamento finito. O segundo problema consiste em encontrar a ordem em que os lotes devem ser produzidos em um dado conjunto de máquinas. Estes dois aspectos do planejamento da produção podem ser tratados de forma independente: em um estágio é resolvido o problema de dimensionamento dos lotes e no outro, realizado antes ou depois, é resolvido o problema de seqüenciamento. No entanto, uma tendência recente na literatura são trabalhos que apresentam modelos matemáticos que capturam simultaneamente as relações entre os dois problemas. Na literatura pode-se encontrar modelos integrados que incluem restrições de eliminação de subrotas, propostas para o Problema do Caixeiro Viajante (PCV), para formular as restrições de sequenciamento. No entanto, alguns dos modelos propostos usam restrições de ordem polinomial que fornecem uma relaxação linear fraca. O objetivo desse trabalho é avaliar o uso de inequações válidas, propostas na literatura, para obtenção de formulações mais fortes para o problema integrado de dimensionamento e sequenciamento da produção. Resultados computacionais usando exemplares aleatórios e exemplares da literatura mostram que as reformulações propostas são eficientes para cenários em que o modelo original não é eficiente.
Often, the production planning involves the lot sizing and scheduling of items. The first problem is to determine the lot size of each item to be produced in one or more machines in each period over a finite planning horizon. The second problem is to find the order in which the items will be produced. These two aspects of the production planning can be treated independently: in one stage the lot sizing problem is solved, and in the other, that can be executed before or after, the scheduling problem is solved. A recent trend in the literature is to propose mathematical models that capture the relationships between these two problems. In the literature one can find integrated models that include subtour elimination constraints, proposed for the Traveling Salesman Problem, to formulate the scheduling decisions. However, in some of these models, constraints of polynomial order, that provides a weak linear relaxation, are used.The purpose of this study is to evaluate the use of valid inequalities proposed in the literature to obtain stronger formulations to the lot and scheduling problem. Computational results using random instances and instances from the literature show that the proposed formulations have a better performance in scenarios where the original model is not efficient.
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Defalque, Cristiane Maria [UNESP]. "Estatégias para incorporação das deçisões de sequenciamento em um problema integrado de produção de bebidas." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/94219.
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Neste trabalho, propomos um modelo integrado de dimensionamento de lotes e programação da produção para uma fábrica de refrigerantes de pequeno porte denominado P1S1MTS. Neste modelo, as decisões de dimensionamento foram baseadas no modelo P1S1M encontrado na literatura, formulado com base no modelo GLSP. As decisões de sequenciamento foram modeladas utilizando restrições do problema do caixeiro viajante assimétrico. Para validação do modelo proposto e comparação entre os modelos P1S1MTS e P1S1M foram feitos testes computacionais com exemplares ilustrativos. Foram realizados também testes com exemplares baseados em dados reais da fábrica de refrigerantes e exemplares gerados aleatoriamente. Os testes foram resolvidos pelo método Branch-and-Cut incluído no pacote computacional CPLEX 10.0. Notamos que com algumas modificações, é possível que ambos os modelos retratem a mesma situação. A partir destas modificações e com os resultados obtidos, concluímos que a resolução de exempalres do modelo P1S1MTS apresentou um tempo de execução computacioanl menor que a resolução de exemplares do modelo P1S1M gerados com os mesmos dados.
In this work we propose a lot sizing and scheduling model, P1S1MTS, for a smallscale soft drink plant. In this model, the lot sising decisions were based on the P1s!m model found in the literaure. To model the scheduling decisions constraints of the asynmetric traveling salesman problem are used. For the validation of the proposed model and a comparison between the P1S1MTS and the P1S1M models computational tests were executed with illustratuve examples. Tests were also executed with examples based on real data and randomly generated instances. Tests were also executed with examples based on real data and randomly in the software CPLEX 10.0. The results showed taht, with some minor modifications, it is possible that both models depict same situation. From the results obtained we concluded that the P1s!MTS model presented a computational time performance better than the P1S1M model.
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Silva, Carla Taviane Lucke da. "Otimização de processos acoplados: programação da produção e corte de estoque." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-13022009-102119/.
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Em diversas indústrias de manufatura (por exemplo, papeleira, moveleira, metalúrgica, têxtil) as decisões do dimensionamento de lotes interagem com outras decisões do planejamento e programação da produção, tais como, a distribuição, o processo de corte, entre outros. Porém, usualmente, essas decisões são tratadas de forma isolada, reduzindo o espaço de soluções e a interdependência entre as decisões, elevando assim os custos totais. Nesta tese, estudamos o processo produtivo de indústrias de móveis de pequeno porte, que consiste em cortar placas grandes disponíveis em estoque para obter diversos tipos de peças que são processadas posteriormente em outros estágios e equipamentos com capacidades limitadas para, finalmente, comporem os produtos demandados. Os problemas de dimensionamento de lotes e corte de estoque são acoplados em um modelo de otimização linear inteiro cujo objetivo é minimizar os custos de produção, estoque de produtos, preparação de máquinas e perda de matéria-prima. Esse modelo mostra o compromisso existente entre antecipar ou não a fabricação de certos produtos aumentando os custos de estoque, mas reduzindo a perda de matéria-prima ao obter melhores combinações entre as peças. O impacto da incerteza da demanda (composta pela carteira de pedidos e mais uma quantidade extra estimada) foi amortizado pela estratégia de horizonte de planejamento rolante e por variáveis de decisão que representam uma produção extra para a demanda esperada no melhor momento, visando a minimização dos custos totais. Dois métodos heurísticos são desenvolvidos para resolver uma simplificação do modelo matemático proposto, o qual possui um alto grau de complexidade. Os experimentos computacionais realizados com exemplares gerados a partir de dados reais coletados em uma indústria de móveis de pequeno porte, uma análise dos resultados, as conclusões e perspectivas para este trabalho são apresentadosIn the many manufacturing industries (e.g., paper industry, furniture, steel, textile), lot-sizing decisions generally arise together with other decisions of planning production, such as distribution, cutting, scheduling and others. However, usually, these decisions are dealt with separately, which reduce the solution space and break dependence on decisions, increasing the total costs. In this thesis, we study the production process that arises in small scale furniture industries, which consists basically of cutting large plates available in stock into several thicknesses to obtain different types of pieces required to manufacture lots of ordered products. The cutting and drilling machines are possibly bottlenecks and their capacities have to be taken into account. The lot-sizing and cutting stock problems are coupled with each other in a large scale linear integer optimization model, whose objective function consists in minimizing different costs simultaneously, production, inventory, raw material waste and setup costs. The proposed model captures the tradeoff between making inventory and reducing losses. The impact of the uncertainty of the demand, which is composed with ordered and forecasting products) was smoothed down by a rolling horizon strategy and by new decision variables that represent extra production to meet forecasting demands at the best moment, aiming at total cost minimization. Two heuristic methods are proposed to solve relaxation of the mathematical model. Randomly generated instances based on real world life data were used for the computational experiments for empirical analyses of the model and the proposed solution methods
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Soler, Willy Alves de Oliveira. "Análise, proposição e solução de modelos para o problema integrado de dimensionamento de lotes e sequenciamento da produção." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-05022018-161825/.
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Esta tese aborda um problema de dimensionamento e sequenciamento de lotes de produção baseado em uma indústria alimentícia brasileira que opera por meio de diversas linhas de produção heterogêneas. Nesse ambiente produtivo, as linhas de produção compartilham recursos escassos, tais como, trabalhadores e máquinas e devem ser montadas (ativadas) em cada período produtivo, respeitando-se a capacidade disponível de cada recurso necessário para ativação das mesmas. Modelos de programação matemática inteira mista são propostos para representação do problema, bem como diversos métodos heurísticos de solução, compreendendo procedimentos construtivos e de melhoramento baseados na formulação matemática do problema e heurísticas lagrangianas. São propostas heurísticas do tipo relax-and-fix explorando diversas partições das variáveis binárias dos modelos e uma heurística baseada na decomposição do modelo para construção de soluções. Procedimentos do tipo fix-and-optimize e matheuristics do tipo iterative MIP-based neighbourhood search são propostas para o melhoramento das soluções iniciais obtidas pelos procedimentos construtivos. Testes computacionais são realizados com instâncias geradas aleatoriamente e mostram que os métodos propostos são capazes de oferecer melhores soluções do que o algoritmo Branch-and-Cut de um resolvedor comercial para instâncias de médio e grande porte.This doctoral dissertation addresses the simultaneous lot sizing and scheduling problem in a real world production environment where production lines share scarce production resources. Due to the lack of resources, the production lines cannot operate all simultaneously and they need to be assembled in each period respecting the capacity constraints of the resources. This dissertation presents mixed integer programming models to deal with the problem as well as various heuristic approaches: constructive and improvement procedures based on the mathematical formulation of the problem and lagrangian heuristics. Relax-and-fix heuristics exploring some partitions of the set of binary variables of a model and a decomposition based heuristic are proposed to construct solutions. Fix-and-optimize heuristics and iterative MIP-based neighbourhood search matheuristics are proposed to improvement solutions obtained by constructive procedures. Computational tests are performed with randomly instances and show that the proposed methods can find better solutions than the Branch-and-Cut algorithm of a commercial solver for medium and large size instances.
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Carretero, Michelli Maldonado. "Formulações fortes para o problema integrado de dimensionamento e sequenciamento da produção /." São José do Rio Preto : [s.n.], 2011. http://hdl.handle.net/11449/94207.
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Orientador: Maria do Socorro Nogueira RangelBanca: Alistair Clark
Banca: Silvio Alexandre de Araujo
Resumo: Em alguns setores, o planejamento da produção envolve dois aspectos: o dimensionamento do tamanho dos lotes e a programação da produção (sequenciamento dos lotes). O primeiro problema consiste em determinar o tamanho dos lotes de produção de cada item a ser produzido em uma ou mais máquinas em cada período ao longo de um horizonte de planejamento finito. O segundo problema consiste em encontrar a ordem em que os lotes devem ser produzidos em um dado conjunto de máquinas. Estes dois aspectos do planejamento da produção podem ser tratados de forma independente: em um estágio é resolvido o problema de dimensionamento dos lotes e no outro, realizado antes ou depois, é resolvido o problema de seqüenciamento. No entanto, uma tendência recente na literatura são trabalhos que apresentam modelos matemáticos que capturam simultaneamente as relações entre os dois problemas. Na literatura pode-se encontrar modelos integrados que incluem restrições de eliminação de subrotas, propostas para o Problema do Caixeiro Viajante (PCV), para formular as restrições de sequenciamento. No entanto, alguns dos modelos propostos usam restrições de ordem polinomial que fornecem uma relaxação linear fraca. O objetivo desse trabalho é avaliar o uso de inequações válidas, propostas na literatura, para obtenção de formulações mais fortes para o problema integrado de dimensionamento e sequenciamento da produção. Resultados computacionais usando exemplares aleatórios e exemplares da literatura mostram que as reformulações propostas são eficientes para cenários em que o modelo original não é eficiente.
Abstract: Often, the production planning involves the lot sizing and scheduling of items. The first problem is to determine the lot size of each item to be produced in one or more machines in each period over a finite planning horizon. The second problem is to find the order in which the items will be produced. These two aspects of the production planning can be treated independently: in one stage the lot sizing problem is solved, and in the other, that can be executed before or after, the scheduling problem is solved. A recent trend in the literature is to propose mathematical models that capture the relationships between these two problems. In the literature one can find integrated models that include subtour elimination constraints, proposed for the Traveling Salesman Problem, to formulate the scheduling decisions. However, in some of these models, constraints of polynomial order, that provides a weak linear relaxation, are used.The purpose of this study is to evaluate the use of valid inequalities proposed in the literature to obtain stronger formulations to the lot and scheduling problem. Computational results using random instances and instances from the literature show that the proposed formulations have a better performance in scenarios where the original model is not efficient.
Mestre
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Leão, Aline Aparecida de Souza. "Extensões em problemas de corte: padrões compartimentados e problemas acoplados." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-03052013-162852/.
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Nesta tese é abordado o problema da mochila compartimentada e o problema de corte de estoque unidimensional acoplado ao problema dimensionamento de lotes. Para o problema da mochila compartimentada é apresentada a versão unidimensional e proposta a versão bidimensional, denominados como problema da mochila compartimentada unidimensional e problema da mochila compartimentada bidimensional, respectivamente. Para o problema de corte de estoque acoplado ao dimensionamento de lotes são apresentadas três variações: uma máquina para produzir um tipo de objeto; uma máquina para produzir vários tipos de objetos; múltiplas máquinas para produzir vários tipos de objetos. Algumas formulações matemáticas de programação inteira e inteira-mista, decomposições dos problemas em problema mestre e subproblemas e heurísticas baseadas no método geração de colunas são propostas para os problemas da mochila compartimenta e o problema acoplado. Em específico, para o problema acoplado são aplicadas decomposições Dantzig-Wolfe, que podem ser por período, por máquina ou por período e máquina. Além disso, uma heurística baseada em grafo E/OU é proposta para o problema da mochila compartimentada bidimensionalIn this thesis we present the constrained compartmentalized knapsack problem and the one dimensional cutting stock problem integrated with the capacitated lot sizing problem. For the constrained compartmentalized knapsack problem, the one dimensional version is presented and the two dimensional version is proposed, called one-dimensional compartmentalized knapsack problem and two-dimensional compartmentalized knapsack problem, respectively. For the cutting stock problem integrated with the capacitated lot sizing problem three variations are considered: one machine to produce one type of object; one machine to produce multiple types of objects; multiple machines to produce multiple types of objects. Some integer and mixed programming formulations, decompositions of the problems in master problem and subproblems and heuristics based on column generation method are proposed for the compartmentalized knapsack problem and the cutting stock problem integrated with the capacitated lot sizing problem. In particular, the period, the machine, and the period and machine Dantzig- Wolfe decompositions are applied for the integrated problem. Moreover, a heuristic based on the graph AND/OR is proposed for the two-dimensional compartmentalized knapsack problem. Computational results show that these mathematical formulations and methods provide good solutions
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Júnior, Douglas José Alem. "Programação estocástica e otimização robusta no planejamento da produção de empresas moveleiras." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-29112011-162103/.
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O planejamento da produção em indústrias moveleiras de pequeno porte é comumente constituído por decisões referentes ao volume de produção e à política de estoque, com o objetivo de minimizar o desperdício de material, os atrasos e as horas-extras utilizadas ao longo do horizonte de planejamento. Administrar tais decisões de uma maneira tratável e eficiente é, em geral, um desafio, especialmente considerando a natureza incerta dos dados. Nessa tese, são desenvolvidos modelos de otimização para apoiar tais decisões no contexto do problema combinado de dimensionamento de lotes e corte de estoque sob incertezas que surge em indústrias moveleiras. Para lidar com as incertezas dos dados, são investigadas duas metodologias: programação estocástica e otimização robusta. Dessa maneira, são propostos modelos de programação estocástica de dois estágios com recurso, assim como modelos estocásticos robustos que incorporam aversão ao risco. A motivação em também desenvolver modelos baseados em otimização robusta é considerar casos práticos em que não há uma descrição probabilística explícita dos dados de entrada, assim como evitar trabalhar com numerosos cenários, o que pode tornar o modelo estocástico computacionalmente intratável. Os experimentos numéricos baseados em exemplares reais de uma empresa moveleira de pequeno porte mostram que as soluções obtidas pelos modelos de programação estocástica fornecem planos de produção robustos e que o (a) decisor (a) pode designar suas preferências em relação ao risco aos modelos, assim como controlar o tradeoff entre o custo total esperado e a robustez da solução. Em relação aos resultados dos modelos de otimização robusta, são obtidos alguns insights entre os chamados budgets de incerteza, as taxas de atendimento da demanda e os valores ótimos. Além disso, evidências numéricas indicam que budgets de incerteza menos conservadores resultam em níveis de serviço razoáveis com baixos custos globais, enquanto a abordagem de pior caso gera, relativamente, boas taxas de atendimento da demanda, mas com custos globais elevadosProduction planning procedures in small-size furniture companies commonly consist of decisions with respect to production level and inventory policy, while attempting to minimize trim-loss, backlogging and overtime usage throughout the planning horizon. Managing these decisions in a tractable and efficient way is often a challenge, especially when the uncertainty of data is taken into account. In this thesis, we develop optimization models to support these decisions in the context of the combined lot-sizing and cutting-stock problem that arises in furniture companies. To deal with data uncertainty, we investigate two methodologies: stochastic programming and robust optimization. In the former case, we propose two-stage stochastic programming models with recourse, as well as robust stochastic models to incorporate risk-aversion. In the latter case, our motivation to investigate robust optimization models is the lack of an explicit probabilistic description of the input data. Furthermore, we want to avoid dealing with a large number of scenarios, which typically lead to computationally intractable stochastic programming models. Numerical experiments based on real data from a small-size furniture plant show that the solutions of the stochastic programming models provide robust production plans so that the decision-maker can assign his or her risk preferences to the model and control the tradeoff between the expected total cost and solution robustness. Regarding the results from the robust optimization models, we provide some insights into the relationship among budgets of uncertainty, fill rates and optimal values. Moreover, numerical evidence indicate that less conservative budgets of uncertainty result in reasonable service levels with cheaper global costs, while worst case deterministic approaches lead to relatively good fill rates, but with prohibitive global costs
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Šustrová, Tereza. "Využití Soft Computingu v rámci řízení objednávkového cyklu." Doctoral thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2016. http://www.nusl.cz/ntk/nusl-240495.
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This doctoral thesis deals with possibilities of using advanced methods of decision-making - Soft Computing, in company’s ordering cycle management. The main aim of the thesis is to propose an artificial neural network model with an optimal architecture for ordering cycle management within the supply chain management. The proposed model will be employed in an organization involved in retailing to ensure smooth material flow. A design and verification of artificial neural networks model for sales prediction is also part of this doctoral thesis as well as a comparison of results and usability with standard and commonly used statistical methods. Furthermore, the thesis deals with finding a suitable artificial neural network model with architecture capable of solving the lot-size problem according to specified inputs. Methods of statistical data processing, economical modelling and advanced decision-making (Soft Computing) were utilized during the model designing process.
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Farhat, Mlouka. "Batch replenishment planning under capacity reservation contract." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0041.
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Nous nous intéressons au Problème de Dimensionnement de Lots mono-produit (PDL) dans une chaîne logistique composée d'un détaillant et d'un fournisseur en y intégrant le contrat buyback et l'approvisionnement par batch. L'objectif est de déterminer un plan d'approvisionnement pour le détaillant pour satisfaire ses demandes déterministes sur un horizon fini, tout en minimisant ses coûts d'approvisionnement et de stockage. Concernant le coût d'approvisionnement, nous supposons deux structures différentes : FTL (Full Truck Load) et OFB (Only Full Batch). Trois types de contrat buyback sont étudiés : avec des périodes de retour fixes, avec une limite de temps sur les retours, et avec des retours uniquement dans les périodes d'approvisionnement. Chaque contrat est caractérisé par un pourcentage de retour maximal qui peut être égal à 100% (retour total) ou inférieur à 100% (retour partiel). Pour le PDL sous le contrat buyback avec des périodes de retour fixes, nous supposons le cas de ventes perdues (lost sales). En outre, un autre concept ajouté dans les PDL sous les trois types de contrat buyback réside dans le fait que le détaillant peut jeter la quantité invendue et non retournée au fournisseur, appelé mise au rebut (disposal). Nous avons modélisé ces différentes extensions du PDL par des Programmes Linéaires en Nombres Entiers (PLNE). Nous avons ensuite développé des algorithmes exacts polynomiaux de programmation dynamique pour certaines extensions, et montré la NP-difficulté pour d'autres. Pour chaque problème résolu en temps polynomial, nous avons comparé l'efficacité et les limites de l'algorithme proposé avec celles des quatre formulations en PLNE. Nous avons également proposé des modèles mathématiques pour les PDL sous d'autres types de contrats de réservation de capacité dans le cas déterministe à multi-périodesWe study the single-item Lot Sizing Problem (LSP) in a supply chain composed of a retailer and a supplier by integrating the buyback contract and the batch ordering. The purpose is to determine a replenishment planning for the retailer to satisfy his deterministic demands over a finite horizon, while minimizing the procurement and inventory costs. Regarding the procurement cost, we assume two different structures: FTL (Full Truck Load) and OFB (Only Full Batch). We consider three types of buyback contract: with fixed return periods, with a time limit on returns, and with returns permitted only in procurement periods. Each contract is characterized by the maximum return percentage being either equal to 100% (full return) or less than 100% (partial return). For the LSP under the buyback contract with fixed return periods, we assume the concept of lost sales. Another concept considered in the LSP's under the three types of buyback contract is the disposal of the unsold and unreturned quantities. We model these different LSP extensions as a Mixed Integer Linear Program (MILP). Thereafter, we develop exact polynomial time dynamic programming algorithms for some extensions and show the NP-hardness of others. For each problem solved in polynomial time, we compare the efficiency and the limits of the proposed algorithm with those of four MILP formulations by performing different tests. Finally, we propose mathematical models for the LSP's under other types of the capacity reservation contract in the deterministic and multi-period case
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Baldo, Tamara Angélica. "O problema integrado de dimensionamento e sequenciamento de lotes no processo de fabricação da cerveja: modelos e métodos de solução." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-12032015-161656/.
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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.
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Martínez, Karim Yaneth Pérez. "Planejamento e programação da produção na indústria de embalagens em polpa moldada." Universidade Federal de São Carlos, 2013. https://repositorio.ufscar.br/handle/ufscar/3827.
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Previous issue date: 2013-09-27Financiadora de Estudos e Projetos
This research deals with the production planning and scheduling problem in the molded pulp packing industry, studying particularly a plant of molded pulp packages for eggs. The production process can be subdivided into two processes: molding process and printing process. The main challenge for production planning activities is on the molding process, where products are produced through tooling that have several molds. These tooling are called "Molding Patterns" or " Conformation Patterns". Each one of the molding patterns can contain one, two, until three kind of molds, allowing to produce several products simultaneously. Producing several products at the time can generate large inventory for low demand products and also null inventory for high demand products. Thus, different inventory levels are defined for each product based on their demand behavior, in order to control inventory quantities. In this way, decisions related to the production planning and scheduling in this production process involve deciding which molding patterns should used, how much time they should be used, and how they should be sequenced. All these should be make taking into account a parallel machine system and sequenced-dependent setups time and costs, in order to minimize inventory and setups costs, as well as penalties associated to inventory out of the specified inventory levels of each product. To represent this problem we proposed two formulations: the first one based on the Capacitated Lot Sizing and Scheduling Problem (CLSP), and the second one based on the General Lot Sizing and Scheduling Problem (GLSP). The results from the models were compared in a set of real word instances of a plant, in order to check the adequacy to represent the decisions involved in the studied production process, as well as the main differences between their production plans and performance of the models. The proposed formulations were also adapted for a particular instance, in order to compare their productions plans against the production plan implement by the studied plant. Results show that the proposed models represent rightly decisions involved in the production planning and scheduling in the molded pulp. Furthermore, the solutions obtained by the proposed models represent production plans with costs significantly lower than the schedule implemented by a real plant in this kind of industry.
Este trabalho aborda o problema de planejamento e programação da produção na indústria de embalagens em polpa moldada, considerando particularmente uma fábrica de embalagens para acondicionamento de ovos. O processo de produção pode ser subdividido em dois processos: processo de moldagem e processo de estampagem. O principal desafio para as atividades de planejamento encontra-se no processo de moldagem, em que a obtenção dos produtos depende da utilização de diferentes ferramentais, formados por um conjunto de moldes. Estes ferramentais são chamados de padrões de conformação ou padrões de moldagem , e podem conter um, dois ou até três tipos de moldes, permitindo a produção simultânea de produtos diferentes. Esta produção simultânea de itens pode gerar grandes níveis de estoque de produtos de baixa demanda e estoques nulos para produtos de alta demanda, desta forma, são definidos diferentes níveis de estoque para cada produto com base no comportamento da sua demanda. As decisões envolvidas no planejamento e programação da produção neste tipo de processo envolve a escolha dos padrões de moldagem a serem utilizados, o tempo de produção de cada padrão, e a sequência em que estes devem ser programados, considerando um sistema de linhas paralelas idênticas e tempos e custos de preparação dependentes da sequência. Estas decisões devem ser definidas de modo a minimizar os custos de estocagem, preparação, e penalidades associadas ao desvio do volume do estoque em relação aos níveis estabelecidos para cada produto. Para representar o problema são propostas dois tipos de formulações: a primeira baseada no Problema de Dimensionamento de Lotes Capacitado (CLSP), e a segunda baseada no Problema de Dimensionamento e Sequenciamento de Lotes Geral (GLSP). Os resultados da resolução dos modelos são comparados com base em exemplares reais da fábrica em estudo, a fim de verificar sua adequação para representar as decisões envolvidas no sistema de produção, as principais diferenças nos planos de produção gerados, e o desempenho destes modelos. Os resultados obtidos demonstram que os modelos propostos representam adequadamente as decisões no sistema de produção estudado, e geram planos de produção significativamente melhores que os planos praticados pela fábrica.
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Junqueira, Rogério de Ávila Ribeiro. "Programação das frentes de colheita de cana-de-açúcar: uma modelagem visando o equilíbrio das capacidades de colheita e transporte." Universidade Federal de São Carlos, 2014. https://repositorio.ufscar.br/handle/ufscar/3449.
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Previous issue date: 2014-06-09The production of sugar, ethanol and electricity from sugar cane necessarily involves harvesting and transportation of raw materials, which are expensive and complex operations and have significant influence on the quality of the industrial raw material. The literature reports several optimization approaches related to the planning of planting, harvesting and transporting of sugarcane, however the scheduling of harvesting fronts is underexplored. This thesis intends to contribute to the state-of-art of this important issue in the context of the Brazilian agribusiness. Optimization approaches to support scheduling decisions of harvesting fronts considering the balance of harvesting and transportation capacities, as well as good agronomic management are proposed. The approaches are inspired by the representation of the problem as a lot sizing and scheduling model with parallel machines and sequence-dependent setup costs and times, a modelling technique well studied in the production planning and control literature. Three variants of this formulation, based on mathematical programming models, were developed and tested in two real case studies of medium size sugar mills. Heuristic methods based on aggregation procedures and mathematical programming have also been studied and developed to solve large scaled problems found in practice. Among the three variants studied, one presented the best solution quality within the expected execution time. Important scenario analysis were done indicating that the schedule s fulfilment provides reduction of harvesting and transporting complexity to the following season, which can generate significant saves in the cases studied. Besides that, comparing the proposed scheduling method with one of the sector s practice, it can be generated also significant cost reduction in the cases studied. The results were analyzed according to a validation methodology (descriptive facet of tetraedrum) well known in the literature.
A produção de açúcar, álcool e energia elétrica a partir de cana-de-açúcar passa necessariamente pela colheita e transporte da matéria-prima, que são operações custosas, complexas e que interferem significativamente na qualidade da matéria-prima industrial. A literatura reporta várias abordagens de otimização relacionadas ao planejamento do plantio, da colheita e do transporte de cana-de-açúcar, todavia a programação das frentes de colheita é pouco explorada. Nesta tese pretende-se contribuir para o estado da arte deste importante tema no contexto do agronegócio brasileiro. Propõe-se abordagens de otimização para apoiar decisões de programação das frentes de colheita, considerando-se o equilíbrio das capacidades de colheita e transporte, bem como um bom manejo agronômico. As abordagens são inspiradas na representação do problema por meio de um modelo de dimensionamento de lotes e sequenciamento da produção em máquinas paralelas com custos e tempos de setup dependentes da sequência, bem estudado na literatura em contextos de planejamento e controle da produção. Para isso foram desenvolvidas três variantes desta formulação baseadas em programação matemática, voltadas para a programação das frentes de colheita, que foram testadas em dois estudos de caso reais de usinas de cana-de-açúcar de médio porte do setor. Métodos heurísticos baseados em procedimentos de agregação e programação matemática também foram estudados e desenvolvidos para a resolução dos problemas de grande porte encontrados na prática. Das três variantes estudadas, uma delas apresentou melhor qualidade da solução dentro de tempos computacionais aceitáveis para o problema. Análises de cenário importantes foram feitas indicando que o cumprimento da programação proporciona redução de complexidade da colheita e transporte na safra seguinte, podendo gerar economias significativas nos casos estudados. Além disso, a comparação dos resultados das abordagens aqui exploradas com o que é praticado no setor indica um potencial de redução de custos também significativo para os casos estudados. Os resultados foram analisados de acordo com uma metodologia de validação (faceta descritiva do tetraedro) conhecida na literatura.
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Rowshannahad, Mehdi. "Qualification Management and Closed-Loop Production Planning in Semiconductor Manufacturing." Thesis, Saint-Etienne, EMSE, 2015. http://www.theses.fr/2015EMSE0784/document.
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La thèse est composée de deux parties. La première partie traite de la gestion des qualifications dans l'industrie des semi-conducteurs. La contrainte de qualification définit l'éligibilité d'une machine à processer un produit. La gestion des qualifications nécessite de résoudre un problème d'allocation et d'équilibrage des charges sur des machines parallèles non-identiques et partiellement reconfigurables. Nous avons défini et introduit des indicateurs pour la gestion des qualifications en tenant compte de la capacité des équipements ainsi que la contrainte de regroupements de lots (batching). Plusieurs algorithmes d'équilibrage de charge sont proposés et validés pour le calcul de la charge optimale sur un parc d'équipements. Ce concept est industrialisé au sein de l'entreprise Soitec et fait partie du processus de prise de décision.La deuxième partie de la thèse porte sur la planification de production en boucle fermée. Le processus de fabrication des plaques SOI à Soitec s'appuie sur la Technologie Smart-Cut. En utilisant cette technologie, une des deux matières premières peut être réutilisée à plusieurs reprises pour la fabrication des produits finis. Le couplage de deux lignes de production crée un système manufacturier en boucle fermée. Nous avons proposé un modèle de dimensionnement de lots original pour la planification de production de ce système manufacturier, que nous avons validé avec des données industrielles. En se basant sur le problème industriel, un problème mono-produit et sans contrainte de capacité est défini, analysé et résolu pour une version simplifiée du problèmeIn the first part, we take a binding restriction, called qualification, present in semiconductor manufacturing as a lever for increasing flexibility and optimizing capacity utilization. A qualification determines the processing authorization of a product on a machine (like an eligibility constraint). In order to define the best qualification, the production volume should be allocated to parallel non-identical machines which are partially reconfigurable. Capacitated flexibility measures are introduced to define the best qualification which increases machine capacity utilization at most. Batching is another industrial constraint encountered in semiconductor industry. It influences workload balancing and qualification management. Several workload balancing algorithms are proposed to find the optimal workload balance of a workcenter. Variability measures are also proposed to evaluate the workload variability of a workcenter. The second part deals with closed-loop production planning. Soitec uses Smart-Cut Technology to fabricate SOI wafers. Using this technology, one of the two raw materials used to fabricate SOI wafers can be reused several times to make other SOI wafers. However, before coming back to the SOI fabrication line, the used raw material (by-product) must be reworked in another production line. An original closed-loop production planning model adapted to the supply chain specificities of Soitec is proposed, and is validated using industrial data. Based on this industrial model, a single-item uncapacitated closed-loop lot-sizing model is defined, analyzed, and a dynamic programming algorithm is proposed for a simplified version of the problem
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Chekoubi, Zakaria. "Problème intégré de dimensionnement de lots et de tournées de véhicules avec remanufacturing des produits en fin de vie." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0209.
Full textAbstract:
Dans une chaîne logistique traditionnelle, les opérations de production, de stockage et de distribution sont traitées séparément en raison de la complexité de la planification conjointe de ces opérations et le manque d'informations partagées entre les parties prenantes. Aujourd'hui, pour faire face à la concurrence féroce que connaît le marché mondial, les entreprises sont obligées de planifier conjointement ces activités afin de bénéficier des avantages économiques et environnementaux engendrés par cette intégration. Parmi les problèmes d’optimisation existants dans la littérature, le problème de la planification intégrée qui optimise conjointement les décisions de production, de gestion des stocks, de distribution et de tournées de véhicules, a récemment fait l'objet d'une attention considérable, malgré sa nature NP-difficile. En effet, ses avantages en termes de synchronisation entre les processus, de réduction des coûts et d’amélioration du niveau de service peuvent être importants. En outre, l’optimisation de ce problème dans le contexte des chaînes logistiques en boucle fermée avec gestion des Produits en Fin de Vie (PFV) conduit au développement de chaînes logistiques de plus en plus durables. De plus, les inquiétudes croissantes sur les enjeux environnementaux liés aux activités industrielles ont conduit à l'émergence de politiques de contrôle des émissions carbone. La prise en compte de ces réglementations peut conduire à un impact positif sur la responsabilité environnementale de l’entreprise. Pour répondre à ces défis, l’objectif de cette thèse consiste à concevoir des modèles et de développer des approches d’optimisation pour résoudre un problème de planification intégrée des opérations de production, de ré-usinage, de stockage et de distribution directe-inverse. Nous avons considéré une chaîne logistique en boucle fermée composée d’une ligne de production de produits neufs, d’une ligne de ré-usinage des PFV retournés, deux stocks pour les produits réutilisables et les PFV à ré-usiner, ainsi que des clients ayant des demandes dynamiques en livraison et en collecte. Le but est de déterminer les quantités optimales à produire, ré-usiner et stocker, ainsi que l’ordre de passage chez les clients afin de satisfaire leurs demandes simultanément en livraison et en collecte, tout en minimisant le coût total dû aux opérations induites. Dans un premier temps, un modèle linéaire en nombres entiers est proposé pour optimiser la chaîne logistique en considérant un ou plusieurs véhicules avec capacité limitée. La deuxième partie de la thèse porte sur le développement d’une heuristique de décomposition à deux phases pour résoudre le modèle intégré étendu. La dernière partie de la thèse est consacrée à l’intégration des émissions du dioxyde de carbone dans les décisions de production, de ré-usinage, de stockage et de distribution et d'étudier le comportement des niveaux d'émissions de carbone dans le cadre de la politique de plafonnement et d'échange de droits d'émission de carbone. Des expérimentations numériques permettent de démontrer l’applicabilité et les limites de nos approchesIn a traditional supply chain, production, inventory and distribution operations are treated separately due to the complexity of jointly planning these operations and the lack of information shared among stakeholders. Today, in order to face the fierce competition in the global market, companies are forced to jointly plan these activities in order to benefit from the economic and environmental benefits generated by this integration. Among the optimization problems existing in the literature, the integrated planning problem which jointly optimizes production, inventory management, distribution and vehicle routes decisions, has recently received considerable attention, despite its NP-hardiness. Indeed, its benefits in terms of synchronization between processes, cost reduction and improved service level can be significant. In addition, the optimization of this problem in the context of closed-loop supply chains with End-of-Life Product (EOL) management leads to the development of increasingly sustainable supply chains. Furthermore, growing concerns about environmental issues linked to industrial activities have led to the emergence of policies to control carbon emissions. Taking these regulations into account can have a positive impact on the company's environmental responsibility. To meet these challenges, the objective of this thesis is to design models and develop optimization approaches to solve an integrated planning problem of production, remanufacturing, storage and direct-reverse distribution operations. We considered a closed-loop supply chain consisting of a production line for new products, a remanufacturing line for returned EOL products, two types of inventories for reusable products and EOL ones to be remanufactured, as well as customers with dynamic demands for delivery and pickups. The goal is to determine the optimal amounts to produce, remanufacture and store, as well as the order of visiting customers in order to meet their requests simultaneously for delivery and pickup, while minimizing the total cost due to the involved operations. First, a linear integer model is proposed to optimize the supply chain system by considering one or more vehicles with limited capacity. The second part of the thesis concerns the development of a two-phase decomposition heuristic to solve the extended integrated model. The last part of the thesis is devoted to the integration of carbon dioxide emissions into production, remanufacturing, inventory and distribution decisions and to study the behavior of carbon emission levels in the context of cap-and-trade policy. Numerical experiments make it possible to demonstrate the applicability and the limits of our approaches
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"On the single level capacitated lot sizing problem." 1998. http://library.cuhk.edu.hk/record=b5889649.
Full textAbstract:
Yip Ka-yun.Thesis (M.Phil.)--Chinese University of Hong Kong, 1998.
Includes bibliographical references (leaves 107-113).
Abstract also in Chinese.
Chapter Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Overview --- p.1
Chapter 1.2 --- Our Contributions --- p.2
Chapter 1.3 --- Organization of the Thesis --- p.4
Chapter Chapter 2 --- Literature Review --- p.5
Chapter 2.1 --- Overview --- p.5
Chapter 2.2 --- Research in Capacitated Lot Sizing Problem without significant setup times --- p.5
Chapter 2.3 --- Research in Capacitated Lot Sizing Problem with setup time consideration --- p.12
Chapter 2.4 --- Summary --- p.15
Chapter Chapter 3 --- Capacitated Lot Sizing Problem with Setup Times --- p.16
Chapter 3.1 --- Overview --- p.16
Chapter 3.2 --- Problem Description and Formulation --- p.20
Chapter 3.2.1 --- Our problem formulation
Chapter 3.2.2 --- Comparison between our problem formulation and traditional problem formulation
Chapter 3.3 --- Description of the Algorithm --- p.26
Chapter 3.3.1 --- Wagner-Whitin algorithm
Chapter 3.3.2 --- Transportation problem
Chapter 3.3.3 --- Consistence test
Chapter 3.3.4 --- Subgradient optimization
Chapter 3.3.5 --- Computation of lower bound
Chapter 3.4 --- Design of Experiment --- p.43
Chapter 3.4.1 --- Product demands
Chapter 3.4.2 --- Setup costs
Chapter 3.4.3 --- Setup times
Chapter 3.4.4 --- Capacity costs
Chapter 3.4.5 --- Inventory holding costs
Chapter 3.4.6 --- Quantity of capacity available for production
Chapter 3.4.7 --- Capacity absorption rate
Chapter 3.4.8 --- Generation of larger problems
Chapter 3.4.9 --- Initialization of Lagrangean multipliers
Chapter 3.4.10 --- Close test
Chapter 3.5 --- Open test --- p.58
Chapter 3.6 --- Managerial Implications --- p.61
Chapter 3.7 --- Summary --- p.61
Chapter Chapter 4 --- Capacitated Lot Sizing Problem without Setup Times --- p.63
Chapter 4.1 --- Overview --- p.63
Chapter 4.2 --- Problem Description and Formulation --- p.64
Chapter 4.3 --- Description of the Algorithm --- p.67
Chapter 4.3.1 --- Decomposition scheme
Chapter 4.3.2 --- Wagner-Whitin algorithm
Chapter 4.3.3 --- Transportation problem
Chapter 4.3.4 --- Subgradient optimization
Chapter 4.3.5 --- Computation of lower bound
Chapter 4.4 --- Design of Experiment --- p.80
Chapter 4.4.1 --- Product demands
Chapter 4.4.2 --- Setup costs
Chapter 4.4.3 --- Capacity costs
Chapter 4.4.4 --- Inventory holding costs
Chapter 4.4.5 --- Quantity of capacity available for production
Chapter 4.4.6 --- Capacity absorption rate
Chapter 4.4.7 --- Generation of larger problems
Chapter 4.4.8 --- Initialization of Lagrangean multipliers
Chapter 4.4.9 --- Selection of the extent of geometrical reduction and exponential smoothing
Chapter 4.4.10 --- Close test
Chapter 4.5 --- Open test --- p.92
Chapter 4.6 --- Managerial Implications --- p.95
Chapter 4.7 --- Comparison with other approaches --- p.96
Chapter 4.7.1 --- Gilbert and Madan's approach
Chapter 4.7.2 --- Our algorithm for CLS problem with setup time consideration
Chapter 4.8 --- Summary --- p.102
Chapter Chapter 5 --- Conclusion --- p.104
Appendix A Vogel's approximation method --- p.106
Bibliography --- p.107
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"A genetic algorithm for the capacitated lot sizing problem with setup times." 2009. http://library.cuhk.edu.hk/record=b5894198.
Full textAbstract:
Chen, Jiayi.Thesis (M.Phil.)--Chinese University of Hong Kong, 2009.
Includes bibliographical references (p. 86-94).
Abstract also in Chinese.
Abstract --- p.i
Acknowledgement --- p.iv
Introduction --- p.1
Chapter 1.1 --- Introduction to the Capacitated Lot Sizing (CLS )problem --- p.1
Chapter 1.2 --- Our contributions --- p.2
Chapter 1.3 --- Organization of the thesis --- p.4
Literature Review --- p.5
Chapter 2.1 --- Research in CLS problem --- p.5
Chapter 2.1.1 --- Reviews in CLS problems --- p.8
Chapter 2.1.2 --- Approaches and methods to solve the traditional CLS problems --- p.9
Chapter 2.1.3 --- Research on Fixed-Charge-Transportation-typed models for CLS problems --- p.13
Chapter 2.2 --- Research in Genetic Algorithm (GA) --- p.15
Chapter 2.3 --- Conclusion --- p.17
Problem Description and Formulation --- p.18
Chapter 3.1 --- The formulation --- p.18
Chapter 3.2 --- Comparison with the traditional formulation --- p.24
Chapter 3.3 --- Conclusion --- p.28
Description of the Heuristic --- p.29
Chapter 4.1 --- Initialization --- p.32
Chapter 4.1.1 --- Setup string generation --- p.32
Chapter 4.1.2 --- Transportation problem --- p.35
Chapter 4.1.3 --- Consistency test --- p.47
Chapter 4.2 --- Selection --- p.50
Chapter 4.3 --- Crossover --- p.50
Chapter 4.4 --- Mutation --- p.52
Chapter 4.5 --- Evaluation --- p.53
Chapter 4.6 --- Termination --- p.54
Chapter 4.7 --- Conclusion --- p.54
Design of Experiments and Computational Results --- p.56
Chapter 5.1 --- Design of experiments --- p.57
Chapter 5.2 --- Discussion of lower bound procedures --- p.63
Chapter 5.3 --- Computational results --- p.65
Chapter 5.3.1 --- CLS problems with setup times --- p.65
Chapter 5.3.2 --- CLS problems without setup times --- p.77
Chapter 5.4 --- Conclusion --- p.82
Conclusion --- p.83
Bibliography --- p.86
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Huang, Pei-Yi, and 黃霈宜. "Solving Capacitated Lot Sizing and Scheduling Problem with Comprehensive Setup Considerations by Tabu Search." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/p8sbp4.
Full text
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Chien, Kuo-Liang, and 簡國樑. "A Study on Multi-Class Multi-Level Capacitated Lot Sizing Problems." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/65042874077577481959.
Full textAbstract:
碩士國立清華大學
工業工程與工程管理學系
87
Due to the exclusion of capacity constraint considerations, it is difficult for a traditional MRP calculation to obtain a feasible production plan. Also, the separation of Lot Sizing Decision and Capacity Requirement Planning calculation makes the setup decisions difficult. In practical application, a production plan should includes multiple demand classes such as order boards and forecasts. How to allocate finite resources to meet the demand of different classes is an important issue. This thesis propose an integrated production planning model that not only considers multiple demand classes but also has the ability to deal with the multi-level capacitated lot sizing problem, which involves setup times, setup costs and lead times. Moreover, it can be applied to the problem with general product structures. In fact, this model integrates four modules known as Master Production Scheduling, Material Requirement Planning, Capacity Requirement Planning and Lot Sizing Decision into a single model. Under multiple demand classes and lot sizing decisions, each demand class problem is a Mixed Integer Programming problem with different priority. By sequentially solving each MIP problem according to its priority, we allocate finite manufacturing resources and generate a feasible production plan. This thesis uses three modern searching algorithms, which are tabu search, adaptive simulated annealing (ASA) and adaptive genetic algorithm (AGA), to solve this problem. Experimental designs and statistical methods are used to evaluate and analyze the performance of these three algorithms. As a result, tabu search has the best performance, ASA ranks second, and AGA is the last.