Originally presented as the author's Thesis--Technische Universität Berlin, 2007. / Includes bibliographical references.

Fernwärme ist aufgrund der verstärkten Förderung der Bundesregierung in den letzten Jahren wieder stärker in den Fokus der Energiewirtschaft gerückt. In Hinblick auf einen wirtschaftlich und energetisch effizienten Betrieb von Fernwärmesystemen ist nicht nur der Einsatz der Wärmeerzeuger mittels einer Einsatzplanung sorgfältig zu organisieren, sondern auch das Betriebsverhalten des Wärmeverteilnetzes selbst zu berücksichtigen. So führen ständig auftretende Änderungen der thermischen Last, der Vorlauftemperatur am Einspeisepunkt oder der Rücklauftemperaturen der Abnehmer zu instationären Betriebszuständen im Fernwärmenetz. Die damit verbundene zeitliche Entkopplung der zentralen Wärmeeinspeisung von der dezentralen Wärmeentnahme induziert eine Speicherung thermischer Energie in dem in den Rohrleitungen befindlichen Wasser und in den Rohren selbst. In den seltensten Fällen wird dieser Vorgang der Wärmespeicherung aktiv genutzt, er tritt vielmehr als eher unerwünschter Nebeneffekt auf. Bei Kenntnis der thermodynamischen Zusammenhänge hingegen lässt sich das Fernwärmenetz durch zielgerichtete Steuerung der Vorlauftemperatur analog einem thermischen Heißwasserspeicher als Wärmespeicher nutzen. Dies ist wiederum für die Betriebs- und Gewinnoptimierung interessant, da so weitere Speicherkapazitäten nutzbar gemacht werden können, um Lastspitzen zu verschieben und KWK-Anlagen zu betreiben ohne zusätzliche Investitionen tätigen zu müssen. In dieser Arbeit wird eine Methode vorgestellt, in der die Netzspeicherleistung mit Hilfe eines thermo-hydraulischen Simulationsprogrammes bestimmt wird, wobei dynamische Effekte wie die veränderliche Vorlauftemperaturen am Einspeisepunkt oder die stark schwankenden Lastanforderungen der Abnehmer in der Berechnungsmethodik realitätsnah abgebildet werden. Für eine aktive Nutzung des Fernwärmenetzes als Wärmespeicher muss der Verlauf der Vorlauftemperatur an die jeweilig gewünschte Netzspeicherleistung angepasst werden. Dazu wird in dieser Arbeit ein vereinfachter Funktionsansatz für die Netzspeicherleistung bestimmt, der zunächst mittels Regressionsanalyse aus den Ergebnissen gezielter thermo-hydraulischer Simulationen ermittelt und anschließend so in eine Einsatzplanung integriert wird, sodass die Vorlauftemperatur als zu optimierende Variable in die Gesamtoptimierung einfließt. Anhand eines realen Anwendungsfalls werden die Möglichkeiten und Grenzen der aktiven Nutzung der Speicherfähigkeit von Fernwärmenetzen aufgezeigt. Insbesondere werden monetäre Gewinnpotentiale bei Anwendung der aktiv gesteuerten Netzspeicherung in durch KWK-Anlagen versorgten Fernwärmenetzen bei gleichzeitigem Stromhandel auf dem Spotmarkt abgeschätzt.

En los últimos años la Logística Inversa se ha hecho relevante no solo para el mundo académico sino también para el empresarial. Las empresas dan cada día más importancia a esta área, debido a los factores medioambientales y a los beneficios derivados del mejoramiento de su proceso de devoluciones. Así mismo, para tener unos procesos de Logística Inversa eficientes y exitosos, es necesaria la colaboración entre los miembros de la cadena de suministro. Esta tesis se concentra en ambos aspectos, Colaboración y Logística Inversa.El propósito de esta tesis es doble; primero, analizar los problemas que sufren hoy en día las empresas en esta área, partiendo de una perspectiva general, y posteriormente analizando la industria editorial española. En segundo lugar, nosotros proponemos cuatro modelos matemáticos concernientes a los problemas de planificación que presentan las empresas cuando incorporan las devoluciones, y finalmente proponemos unas metodologías para solucionarlos. / During last years Reverse Logistics has become a relevant topic not only for academics but also for the business world. Companies are giving each day more and more importance to this field, because the environmental issues and the benefits that the company can obtain by the improvement of their return's processes. To obtain a successful and efficient Reverse Logistics processes there exist the need to collaborate along the supply chain. This thesis focuses on both of these two topics, Collaboration and Reverse Logistics. The aim of this thesis is twofold; first, we try to understand the returns processes' problems that companies are facing today from the management point of view, from a general perspective and afterwards on the editorial industry. Secondly, we propose some mathematical models and solution methods related to real planning problems faced by the companies when the returns are incorporated.

Thesis (MEng)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Artificial intelligence has provided several techniques with applications in manufacturing. Knowledge based systems, neural networks, case based reasoning, genetic algorithms and fuzzy logic have been successfully employed in manufacturing. This thesis will provide the reader with an introduction and an understanding of each of these techniques (Chapter 2 & 3). The intelligent manufacturing process can be a complex one and can be decomposed into several components: intelligent design, intelligent process planning, intelligent quality management, intelligent maintenance and diagnosis, intelligent scheduling and intelligent control. This thesis will focus on how each of the artificial intelligence techniques can be applied to each of the manufacturing process fields. Chapter 5 Chapter 6 Chapter 7 Knowledge based systems Neural networks Fuzzy logic Case based reasoning Genetic algorithms Chapter 8 Chapter 9 Chapter 10 Manufacturing intelligence can be approached from two main directions: theoretical research and practical application. Most of the concepts, methods and techniques discussed in this thesis are approached from a theoretical research point of view. This thesis is also aimed at providing the reader with a broader picture of manufacturing intelligence and how to apply the intelligent techniques, in theory. Specific attention will be given to intelligent scheduling as an application (Chapter 11). The application will demonstrate how case based reasoning can be applied in intelligent scheduling within a small manufacturing plant. / AFRIKAANSE OPSOMMING: Kunsmatige intelligensie bied 'n verskeidenheid tegnieke en toepassings in die vervaardigingsomgewing. Kennis baseerde sisteme, neurale netwerke, gevalle basseerde redenasie, generiese algoritmes en wasige logika word suksesvol in die vervaardigingsopset toegepas. Dié tesis gee die leser 'n inleiding en basiese oorsig van metodes om elk van die tegnieke te gebruik (hoofstuk 2 & 3). Die intelligente vervaardigingproses is 'n komplekse proses en kan afgebreek word in verskeie komponente: intelligente ontwerp, intelligente prosesbeplanning, intelligente gehaltebestuur, intelligente onderhoud en diagnose, intelligente kontrole en intelligente skedulering. Hierdie tesis sal fokus op hoe elk van die kunsmatige intelligente tegnieke op elk van die vervaardigingprosesvelde toegepas kan word. Hoofstuk 5 Hoofstuk 6 Hoofstuk 7 Kennis gebaseerde sisteme Wasige logika Neurale netwerke Gevalle baseerde redenasie Generiese algoritmes Hoofstuk 8 Hoofstuk 9 Hoofstuk 10 Vervaardigingsintelligensie kan vanuit twee oogpunte benader word, naamlik 'n teoretiese ondersoek en 'n praktiese aanslag. Die meeste van hierdie konsepte, metodes en tegnieke word in hierdie tesis vanuit 'n teoretiese oogpunt benader. Die tesis is daarop gerig om die leser 'n wyer perspektief te gee van intelligente vervaardiging en hoe om die intelligente tegnieke, in teorie, toe te pas. Spesifieke aandag sal gegee word aan intelligente skedulering as 'n toepassing (Hookstuk 11). Die toepassing sal demonstreer hoe gevalle baseerde redenasie toegepas kan word in intelligente skedulering.

A incorporação de tecnologias computacionais tende a agilizar o gerenciamento dos processos de produção e auxiliar no plano logístico das empresas, pois é capaz de a partir de dados armazenados, realizar análises e agregar informações valiosas em termos de conhecimento e avaliação de dados em busca de soluções para melhoria dos processos e gestão com maior qualidade. A presente pesquisa objetivou a realização de estudos em relação à variação da qualidade da matéria prima, ao longo do ano, por meio de dados documentais de 3 anos, dos teores de fécula das raízes de mandioca entregues pelos produtores. Os dados foram obtidos por meio de coletas de valores de massa em água por balança hidrostática existente na agroindústria e utilizada na qualificação do produto e cálculo de pagamento ao agricultor. Realizou-se uma avaliação do setor de recepção por meio de simulação dinâmica e estocástica, com base em resultados de tempos obtidos por acompanhamento in loco e coletas ao longo de dois anos nos meses de safra, bem como a construção de um modelo de previsão de demanda, baseado em dados de 10 anos de vendas de fécula, arquivados em banco de dados da empresa. A pesquisa pode ser classificada metodologicamente como um estudo de abordagem quantitativo e qualitativo, de natureza aplicada e objetivo explicativo, a qual se utilizou dos procedimentos das pesquisas documental e operacional. O objeto de estudo foi uma fecularia da região Oeste do estado do Paraná. Para a execução do estudo utilizou-se de diversos softwares computacionais tais como Arena®, Statistica®, Gretl, Action Stat®, Wessa Net, NNQ e Stat Pro, visando identificar as técnicas mais adequadas para a simulação do processo de recepção e a previsão de demanda de produto acabado, auxiliando a tomada de decisão.Percebeu-se que a demanda pelo produto acabado vem crescendo ao longo dos anos e que após análise de previsão por modelo, apresentou tendência de continuar seu crescimento o que justifica a preocupação com a excessiva formação de filas no setor de recepção de matéria prima em épocas de safra, sendo que ficou evidente a necessidade de uma avaliação dos gargalos deste setor, dessa forma o realizou-se uma simulação para conhecimento mais aprofundado dos gargalos deste processo. Após a simulação observouse que o principal gargalo do setor de recebimento do produto foi o equipamento de descarga. Porém estudando-se mais a fundo o processo observou-se que existem gargalos subsequentes a esse no sistema de estocagem e processamento da fécula, o que demandaria excessivos investimentos para o presente momento econômico. Dessa forma, acredita-se que seriam mais importantes propostas de alteração gerencias, as quais foram apresentadas, bem como uma sugestão de alteração na metodologia de cálculo do valor a ser pago ao agricultor pela grama do amido, com objetivo de minimizar a entrega de raízes de forma muito superior nos meses de safra e a ociosidade em outros meses. As alternativas apresentadas podem auxiliar na redução da sazonalidade, porém cabe destacar que sempre existirá elevada interferência de fatores edafoclimáticos e genéticos que dificultarão a obtenção de raízes de mandioca com elevados teores de fécula em determinadas épocas do ano. / The incorporation of computational technologies tend to streamline the management of the production processes and help in the logistical plan of the companies, because from the stored data, it is capable of performing analyzes and aggregate valuable information involving knowledge and data evaluation in search of solutions to improve both, processes and management. This study aimed to carry out studies on the variation of the quality of the raw material during the year through, the starch contents of the cassava roots delivered by the producers, using documentary data from 3 years ago. This data were obtained through collections of mass values in water by hydrostatic balance in the agricultural industry and used in the qualification of the product and payment calculation to the farmer. An evaluation of the reception sector was carried out through dynamic and stochastic simulation, based on the results of time obtained by in-situ monitoring and collection over two years in the harvesting months, as well as the building of a demand forecasting model, based on data from 10 years of starch sales, filed in the company's database. The research can be methodologically classified as quantitative and qualitative approach, with applied nature and explanatory objective, which used documental and operational researches procedures. The object of study was a cassava starch industry in the western region of Paraná. For the execution of the study, several computational softwares such as Arena®, Statistica®, Gretl, Action Stat®, Wessa Net, NNQ and Stat Pro were used to identify the most appropriate techniques for simulation of the reception process and the demand forecasting of finished product, assisting decision making. It was noticed that the demand for the finished product has been increasing over the years and that after analysis of forecasting by the model, it was shown a tendency to continue its growth which justifies the concern with the excessive formation of queues in the raw material reception sector during harvesting, and it was evident the need for an evaluation of the bottlenecks of this sector, so a simulation was carried out for a more in-depth knowledge of the bottlenecks of this process. After the simulation it was observed that the main bottleneck in the product receiving process was the discharge equipment. However, studying the process more deeply, it was observed that there are subsequent bottlenecks in the storage and starch processing systems, which would require excessive investments for the current economic moment. Due to this economic moment, it is believed that proposals of management alterations, which were presented, as well as a suggestion of alteration in the payment calculation methodology of the value to be paid to the farmer using the starch content in grams, aiming to minimize the high delivery of roots in the harvesting months and idleness in other months, would be more important. The alternatives presented may help reduce seasonality, but it is important to emphasize that there will always be high interference of genetic and edaphoclimatic factors that will make it difficult to obtain cassava roots with high starch content at certain times of the year.

Diante de um crescimento econômico, as empresas de maneira geral e, em particular, a indústria de manufatura, acabam procurando um meio de eliminar perdas que estão em evidência e outras que não estão tão expostas, para assim maximizar seus lucros. Este trabalho mostra uma programação de produção otimizada, de modo a aumentar a disponibilidade de um equipamento responsável em manufaturar mais de um modelo de produto. Com exigências cada vez maiores, os consumidores obrigam a indústria a variar seu mix de produção de modo a não poder mais possuir equipamentos dedicados para cada tipo de modelo produzido. Com isso, exige-se cada vez mais o uso de abordagens de pesquisa operacional para poder montar um cronograma de produção de forma mais rápida e assertiva. Não se pode deixar de considerar a influência da disponibilidade do equipamento para o bom andamento da programação da produção. Alinhado a isto ao avaliar as maiores perdas de um equipamento, verifica-se a necessidade de se reduzir seu tempo de set-up. Para que isto seja possível, é sugerida a aplicação da metodologia SMED, a qual foi criada dentro do sistema Lean Manufacturing, mais especificamente do sistema TPM. Do ponto de vista da otimização, o problema proposto é desafiador, já que há múltiplos processadores idênticos, em paralelo e o set-up entre os produtos é dependente da sequência de produção. Assim, cabe ao sistema proposto definir quanto da demanda total de cada produto será produzida em cada um dos processadores, visando a minimização do tempo total de set-up. Ou seja, os lotes de produção não têm tamanho fixo. Foi proposta uma abordagem híbrida usando regras de despacho (heurísticas) para a solução do problema proposto, com resultados satisfatórios. / Due to economic growth, companies in general – but particularly manufacturing industries - end up looking for a way to eliminate losses that are evident and others that are not so easy to identify so as to maximize profits. This project seeks for an optimal production schedule to increase the availability of a device responsible for manufacturing more than one product. With increased demands from customers, industry is compelled to vary its production mix so that it can not have equipment dedicated to each produced model type. Thus, the use of operational research approaches is more and more required to be able to set up a production schedule in a faster and assertive way. One can not stop considering the influence of equipment availability for a smoother production scheduling. Aligned with this, when evaluating the major losses at the equipment, there is a need to reduce the set-up time. To make this possible, it is suggested the implementation of the SMED methodology, which was created within Lean Manufacturing - more specifically, by TPM system. From the perspective of optimization, the proposed problem is challenging since there are multiple identical parallel processors with sequence dependent set-ups. Thus, it is up to the proposed system to define how much of the total demand for each product will be produced in each of the processors in order to minimize the total set-up time. In other words, production lots have no fixed size. It was proposed a hybrid approach using dispatch rules (heuristics) for the solution of the proposed problem that have presented satisfactory results.

Made available in DSpace on 2014-06-11T19:26:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-07-30Bitstream added on 2014-06-13T20:55:45Z : No. of bitstreams: 1 cavali_r_me_sjrp.pdf: 560996 bytes, checksum: 6792ea8d0dd5f26eb5250b68217a4443 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Diariamente, em indústrias de móveis, painéis retângulares de madeira são cortados em retângulos menores para a manufatura de seus produtos. Por causa da possível perda de material envolvida neste processo e de sua influência no custo dos produtos, existe a necessidade de um planejamento prþevio para a realização dos cortes. Na maioria das empresas de móveis situadas na região Noroeste do estado de São Paulo, este planejamento é feito manualmente e não é uma tarefa simples. O enfoque deste trabalho þe analisar a utilização de um sistema computacional no planejamento do corte de painéis de madeira. Esta ferramenta é capaz de resolver o problema do corte bidimensional segundo o algoritmo de dois estþagios de Gilmory e Gomore. Aspectos práticos encontrados no corte dos painéis e estratégias adotadas pelas empresas no planejamento da produção são abordados. Além disso, apresentamos os resultados de um estudo computacional com base em dados reais de uma das empresas visitadas. / In the furniture industries, the cut of rectangular plates to produce smaller rectangular pieces is an every day task. To reduce the waste of material involved in this process and its influence in the cost of the products, a previous planning for the cuts is necessary. In the majority of the furniture companies situated at Northwest region of the state of São Paulo, the generation of cutting patterns is made manually and it is not a simple task. The goal of this work is to analyze the use of a computational system in the cutting patterns generation. This computational system is able to solve the two-dimensional cutting stock problem by the 2-stage Gilmory and Gomore method. Practical aspects found in the cutting patterns generation and strategies adopted for the companies in the production planning are discussed. We also report some results of the application of the computacional system to the cutting patterns generation based on real data of one company.

L'industrie des semi-conducteurs est caractérisée par une production de forte variabilité et de faible volume, des flux de production ré-entrants ainsi que d'un processus de fabrication complexe. Au sein de ce contexte industriel complexe, a été considéré un problème de planification à capacité finie. C'est le problème de projection des encours de production et des commandes clients à capacité finie. Il s'agit d’estimerles dates de début, les temps d'attente et les dates de fin de chacun des steps des différents lots ainsi que la charge accumulée sur les équipements. Cette projection doit tenir compte des contraintes de capacité et qualifications des équipements et des dates d'échéance de livraison des lots. La contrainte de qualification définit l'éligibilité d'un équipement à traiter un produit. Ainsi, l'objectif de cette étude consiste à établir un plan de production réalisable à moyen terme. Afin de réaliser cet objectif, des méthodes exactes et approchées sont proposées. Des résultats en termes de complexité, et d'algorithmes de résolution, ont permis une application industrielle, dans la mesure où un logiciel de planification de la production à capacité finie a été développé. / In this study, we consider the problem of production planning in the semiconductor industry characterized by high mix low volume production, reentrant flows and complex manufacturing process.The aim of this work is to establish a feasible production schedule that takes into account the limited capacity of the manufacturing system, equipment qualifications constraints and delivery due dates. In this context, we have formulated the objective and constraints in a mixed linear program (MIP). The objective of the MIP is to minimize delivery delays to guarantee on-time delivery. While executing different tests of the MIP, we have reached a limit of resolution in a reasonable time. Thus, we use an approximate method to solve the problem. The results show the effectiveness of the heuristic established as solution quality and time resolution.The obtained results led to an industrial application and a software that provides feasible schedules in reduced execution time in a specific fab.

No Brasil, as hortaliças são produzidas, em diferentes épocas do ano, por milhares de agricultores familiares, distribuídos por todo o país. Por ser uma atividade que admite maior complexidade que as demais atividades agrícolas, esta tese propõe um sistema de planejamento da produção olerícola (SPPO) para as unidades de produção familiar (UPFs). Para o desenvolvimento do SPPO utilizou-se uma metodologia, dividida em quatro fases. A primeira fase consistiu no levantamento de fatores e variáveis intervenientes no processo decisório (para quem, o que, quando e quanto produzir) utilizando-se a análise de conteúdo. Os resultados encontrados foram submetidos ao crivo dos especialistas em olericultura e olericultores familiares, por meio de entrevistas individuais, para definir quais elementos incorporar ao SPPO. Na segunda fase estruturou-se o banco de dados do SPPO de acordo com os resultados da primeira fase. A terceira fase, denominada processo de filtragem, além de contemplar a experiência do olericultor na escolha dos canais de distribuição, hortaliças e confrontar as recomendações agrotécnicas com as condições edafoclimáticas da localidade, busca reduzir a dimensão do problema de planejamento do sequenciamento de produção. A quarta fase consistiu na modelagem matemática para a definição da combinação de produção que será recomendado para a UPF em estudo. Ainda, nesta fase é proposta uma metodologia multiíndice para analisar a viabilidade econômica da produção recomendada pelo SPPO. Entre as vantagens do SPPO, destacam-se: (i) consideração dos fatores mercadológicos, agroecológicos, agrotécnicos, agrotecnológicos, capacidade (área, recursos humanos, hídricos e financeiros) e de base ecológico-sustentável que são incorporados em função das escolhas do olericultor; (ii) maior entendimento da complexidade que envolve o desenvolvimento da atividade; (iii) levantamento das despesas e receitas semanais durante o horizonte de planejamento; e (iv) visualização das atividades (tarefas) que devem ser realizadas para o desenvolvimento do planejado. Foram realizados estudos de caso, utilizando dados reais adaptados de UPFs do município de Pato Branco/PR, para mostrar a viabilidade do SPPO como ferramenta auxiliar no planejamento da produção de hortaliças nas UPFs. / In Brazil, vegetables are produced in different year seasons by thousands of family farms distributed throughout the country. Being an activity that allows bigger complexity than other agricultural activities, this thesis proposes a olericultural production planning system (SPPO) for the family production units (UPFs). For the development of the SPPO it was applied a methodology divided into four phases. The first phase consisted in collecting the factors and variables intervenient in the decisive process (to whom, what, when, and how much to produce) using the content analysis. The results found were submitted to the appreciation of olericulture specialists and family olericulturists, by means of individual interviews, to define which elements to incorporate to the SPPO. In the second phase the SPPO data bank was structured according to the first phase results. The third phase, denominated filtration process, besides contemplating the olericulturist´s experience in the choice of the distribution canals, vegetables, and in confronting the agrotechnical recommendations with the edafoclimatical conditions of the place aims at reducing the dimension of the problem of production sequencing planning. The fourth phase consisted in the mathematical modeling to the definition of production combination which will be recommended to the UPF being studied. In this phase it is still proposed a multiindex methodology to analyze the economical viability of the production recommended by the SPPO. Among the SPPO advantages can be mentioned: (i) consideration of market agroecological, agrotechnical, agrotechnological factors, capacity (area; human, hydric, and financial resources), and of ecological-sustainable basis that are incorporated according to the olericulturist´s choices; (ii) greater understanding of the complexity that involves the activity development; (iii) calculating the weekly expenses and revenue during the planning horizon; and (iv) visualization of the activities (tasks) that must be performed to the development of what has been planned. Case studies were performed, using actual data adapted to the UPFs in the city of Pato Branco/PR to show the viability of the SPPO as an auxiliary tool in planning vegetables production in the UPFs.

Cette thèse a pour objectif d'étudier l'utilisation de la programmation par contraintes pour développer un solveur de planification de production. Nous nous concentrons sur des problèmes de dimensionnement de lots de production (lot-sizing) qui sont des problèmes majeurs et difficiles de la planification de la production et profitons d'une des principales forces de la programmation par contraintes, à savoir les contraintes globales. Nous définissons une contrainte globale LotSizing qui s'appuie sur un problème générique de lot-sizing mono-produit à un seul niveau, qui tient compte des capacités de production et de stockage, des coûts unitaires de production et de stockage et des coûts fixes. Cette contrainte globale est un outil de modélisation intuitif pour les problèmes complexes de lot-sizing car elle permet de modéliser chaque nœud des réseaux de distribution. Nous utilisons des techniques de programmation dynamique classiques du lot-sizing pour développer des algorithmes de filtrage pour la contrainte globale. Nous modélisons également des problèmes multi-produits.Enfin, nous introduisons un nouvel algorithme de filtrage générique s'appuyant sur la programmation linéaire. Nous montrons que la cohérence d'arc pour les contraintes considérées peut être obtenue avec la résolution d'un seul programme linéaire lorsque la contrainte a une formulation idéale et nous généralisons le résultat pour faire du filtrage partiel lorsqu'aucune restriction n'est faite sur ces contraintes. Cette technique peut être pertinente lors de la résolution de sous-problèmes de flot ou de séquence sous-jacents au lot-sizing. / In this thesis we investigate the potential use of constraint programming to develop a production planning solver. We focus on lot-sizing problems that are crucial and challenging problems of the tactical level of production planning and use one of the main strengths of constraint programming, namely global constraints. The goal of this work is to set the grounds of a constraint programming framework for solving complex lot-sizing problems. We define a LotSizing global constraint based on a generic single-item, single-level lot-sizing problem that considers production and inventory capacities, unitary production and inventory costs and setup costs. This global constraint is an intuitive modeling tool for complex lot-sizing problems as it can model the nodes of lot-sizing networks. We use classical dynamic programming techniques of the lot-sizing field to develop powerful filtering algorithms for the global constraint. Furthermore we model multi-item problems that are natural extensions of the core problem.Finally we introduce a new generic filtering algorithm based on linear programming. We show that arc consistency can be achieved with only one call to a linear programming solver when the global constraint has an ideal formulation and adapt the result to provide partial filtering when no restriction is made on the constraints. This technique can be useful to tackle polynomial lot-sizing underlying flow and sequence sub-problems.