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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Detecção de vazamentos e alterações em redes de distribuição de água para abastecimento, durante a operação, usando sinais de pressão / Leak and anomaly detection on water supply networks, while operating, using pressure signals

Maria Mercedes Gamboa Medina 16 August 2017 (has links)
O controle ativo de vazamentos é fundamental para o gerenciamento dos recursos hídricos, e particularmente o problema de sua detecção precisa de alternativas de solução. Nesta pesquisa foram desenvolvidos três métodos para detecção da ocorrência de vazamentos ou outras alterações em redes de distribuição de água para abastecimento, durante operação, com base na análise dos sinais de pressão adquiridos por monitoramento permanente na rede. Os métodos foram desenvolvidos com informações de um estudo de caso real, e fundamentam-se em cadeias de Markov, em controle estatístico de processos, e em comparação com padrões, respetivamente. Seu desempenho global foi quantificado com a área abaixo da curva ROC, obtendo valores médios de 0,67, 0,65 e 0,71, respetivamente. Foi encontrado que a ocorrência de vazamentos produz mudanças nas pressões medidas na rede, mas tais mudanças podem ser próximas às que acontecem pela operação normal, de forma que os métodos propostos constituem ferramentas de suporte ao gerenciamento úteis, sem atingir a detecção e diferenciação da totalidade dos vazamentos e alterações. / Active leak control is fundamental on water resources managment, and particullary the detection problem needs alternative solutions. On this research three methods for leak or anomaly detection on operating supply systems were developed, based on analisys of pressure signals acquired by network monitoring. The proposed methods used real data from a case study, and are based on Markov chains, statistical process control, and pattern comparison, respectively. Their overall performances on case study were measured using the area under ROC curve, reaching averages 0,67, 0,65 and 0,71, respectively. It was found that a leak onset result in disturbances on measured preassure, but sometimes those disturbances are close to those of normal operation, therefore proposed methods are useful decision tools, not reaching detection and distinction for all the leaks or anomalies.
12

Detecção de vazamentos e alterações em redes de distribuição de água para abastecimento, durante a operação, usando sinais de pressão / Leak and anomaly detection on water supply networks, while operating, using pressure signals

Gamboa Medina, Maria Mercedes 16 August 2017 (has links)
O controle ativo de vazamentos é fundamental para o gerenciamento dos recursos hídricos, e particularmente o problema de sua detecção precisa de alternativas de solução. Nesta pesquisa foram desenvolvidos três métodos para detecção da ocorrência de vazamentos ou outras alterações em redes de distribuição de água para abastecimento, durante operação, com base na análise dos sinais de pressão adquiridos por monitoramento permanente na rede. Os métodos foram desenvolvidos com informações de um estudo de caso real, e fundamentam-se em cadeias de Markov, em controle estatístico de processos, e em comparação com padrões, respetivamente. Seu desempenho global foi quantificado com a área abaixo da curva ROC, obtendo valores médios de 0,67, 0,65 e 0,71, respetivamente. Foi encontrado que a ocorrência de vazamentos produz mudanças nas pressões medidas na rede, mas tais mudanças podem ser próximas às que acontecem pela operação normal, de forma que os métodos propostos constituem ferramentas de suporte ao gerenciamento úteis, sem atingir a detecção e diferenciação da totalidade dos vazamentos e alterações. / Active leak control is fundamental on water resources managment, and particullary the detection problem needs alternative solutions. On this research three methods for leak or anomaly detection on operating supply systems were developed, based on analisys of pressure signals acquired by network monitoring. The proposed methods used real data from a case study, and are based on Markov chains, statistical process control, and pattern comparison, respectively. Their overall performances on case study were measured using the area under ROC curve, reaching averages 0,67, 0,65 and 0,71, respectively. It was found that a leak onset result in disturbances on measured preassure, but sometimes those disturbances are close to those of normal operation, therefore proposed methods are useful decision tools, not reaching detection and distinction for all the leaks or anomalies.
13

A hybrid decision aid approach for supply networks of multi-site enterprises redesign and strategic planing / Une démarche hybride d'aide à la décision pour la reconfiguration et la planification stratégique des réseaux logistiques des entreprises multi-sites

Pirard, Florence 20 September 2005 (has links)
This thesis presents a hybrid decision aid approach for supply networks redesign and planning int the context of multi-site enterprises. This approach is iterative and integrates a mixed integer programming model and a simulation model being at different decisional levels : the mathematical model is a strategic/tactical model and the simulation model is a tactical/operational model. These two models are based on the same modelling of the supply network. First, we describe the elements constituting the decision aid approach. We present two generic mixed integer programming models, multi-product, multi-echelon and multi-period, which search to maximize the profit of the multi-site enterprise. We propose a heuristic approach to solve one of these programs. We describe the developed simulation model. It reproduces the behaviour of the whole supply chain and takes into account the management policies. then, we present the adopted integration methodology. For a problem based on industrial cases, we show that the two models have their role in the decision aid approach and that they contribute both in the search of a good quality network design.
14

Contribuições das associações de ação coletiva para coordenação de redes de suprimentos: estudo de caso da rede da construção civil no Brasil

Maita, Márcio Antonio 22 March 2005 (has links)
Made available in DSpace on 2010-04-20T20:51:55Z (GMT). No. of bitstreams: 3 142122.pdf.jpg: 20296 bytes, checksum: 90f153038020d7ff5ac21790fa0bbec6 (MD5) 142122.pdf: 1110716 bytes, checksum: 75b5900f6a098625f6ab8439bea6453a (MD5) 142122.pdf.txt: 310684 bytes, checksum: 96bb3d0c399052cb36de25f11032ea9c (MD5) Previous issue date: 2005-03-22T00:00:00Z / Esta pesquisa insere-se no campo de estudos das redes e cadeias de suprimentos, como estruturas fragmentadas e complexas de organização de empresas autônomas para produção de pacotes de valor, necessários para atender os desejos e necessidades dos clientes. Procura responder como essas redes de suprimentos, e as empresas e cadeias que as compõem, são coordenadas para produzir em conjunto. Especificamente, busca compreender como as associações de ação coletiva contribuem para sua coordenação. Com base na revisão da literatura de redes de suprimentos e de associações de ação coletiva, foi projetada uma pesquisa de múltiplos casos nas associações da rede de suprimentos da construção civil no Brasil. Os resultados indicam que novos processos e mecanismos de coordenação das redes estão sendo criados ou reformulados para atender às exigências da nova estrutura de produção em redes. É proposta uma série de ações coletivas para melhorar as operações e gestão das empresas, cadeias e redes. / This research belongs to the field of studies of the supply networks, as fragmented and complex organization and structure of independent firms, to produce and deliver value packages (goods and services) needed to satisfy the clients’ wills and needs. Research to answer how these networks, and the supply chains and firms embedded in it, are coordinated to produce together. Specifically, research to understand how associations of collective action contribute to it. Based on the supply chain and networks literature revision, a field multiple cases research was designed, on collective action associations in the construction industry in Brazil. The results show that new processes and mechanisms of network coordination are being created or reshaped to reach the demands of the new network production structure. It is proposed a series of collective social actions to improve operations and management of firms, supply chains and supply networks.
15

Análise de redes de abastecimento de biomassa com resíduos densificados / Biomass supply network analysis with densified waste

Possidônio, Elisangela Fernandes da Silva Campana 06 March 2015 (has links)
Made available in DSpace on 2016-06-02T19:53:33Z (GMT). No. of bitstreams: 1 POSSIDONIO_Elisangela_2015.pdf: 32497248 bytes, checksum: e1ac761b7dbf730a3de9ba9fca779a0e (MD5) Previous issue date: 2015-03-06 / Biomass has acquired increasing importance as an alternative energy source. The fact of it being considered one of the main alternatives for diversification of energy sources and reducing dependence on fossil fuels, has increased its market acceptance. Despite of being a cheap and renewable source and Brazil being a large production of agricultural and forestry biomass, the use of such waste find some barriers; because of low density and low energy efficiency, which can increase the cost to use. The densification of biomass has drawn attention due to the superiority of the biomass in nature, in relation to the physical characteristics and the characteristic combustion. This work aims in a general way, studies how occurs the distribution of biomass from the product available local to the points of consumption, more specifically to assess the impact of biomass densification in the distribution operations and on transport costs. As a complement, a goal is to make a comparative study of supply with renewable fuel and non-renewable, more specifically with natural gas. For the characterization of supply networks and data collection were carried out visits to companies in this kind of industry, and to compare the costs in distribution operations, it was used a transport model. The results of the comparative study of the scenarios presented the possibility of reduction of 51-60% in transport costs and a 63% reduction in the number of vehicles used for the supply network. However, the cost of densified materials increased total cost in 41.6% in relation to waste in nature. In the comparative study of supply with renewable and nonrenewable fuel materials considered in the study showed economic advantages over natural gas. / A biomassa tem adquirido importância crescente como fonte de energia alternativa. A possibilidade de diversificação da matriz energética, com redução da dependência dos combustíveis fósseis, tem ampliado sua aceitação no mercado. Apesar de ser uma fonte barata e renovável e o Brasil ser um grande produtor de biomassa agrícola e florestal, o aproveitamento desses resíduos encontra barreiras, devido à baixa densidade e baixo rendimento energético, que podem elevar o custo para sua utilização. Como opção, a densificação da biomassa tem chamado a atenção devido à superioridade sobre a biomassa in natura, em relação às características físicas e ao poder calorífico. Este trabalho visa estudar como ocorre a distribuição de biomassa a partir dos locais de disponibilização do produto até os pontos de consumo, além de avaliar o impacto da densificação da biomassa nas operações de distribuição e nos custos de transporte. De forma complementar, elaborou-se um estudo comparativo entre o abastecimento com combustível renovável e não-renovável, mais especificamente, com gás natural. Para a caracterização das redes de abastecimento e coleta de dados foram realizadas visitas a empresas do ramo, e para a comparação dos custos nas operações de distribuição, utilizou-se um modelo de transporte. Os resultados do estudo comparativo dos cenários apresentaram a possibilidade de redução de 51% a 60% nos custos de transporte e uma redução de 63% na quantidade de veículos utilizados para o abastecimento da rede. No entanto, o custo do material densificado elevou os custos totais em 41,6% em relação aos resíduos in natura. No estudo comparativo do abastecimento com combustível renovável e não-renovável os materiais considerados no trabalho apresentaram vantagens econômicas em relação ao gás natural.
16

Projeto de rede de suprimentos: um modelo colaborativo para estruturação da rede de navipeças na Indústria de Construção Naval do Brasil. / Supply network project: a collaborative framework for the structuring of the ship components network of the brazilian shipbuilding industry.

Adriane Angélica Farias Santos Lopes de Queiroz 10 February 2009 (has links)
O objetivo deste estudo foi propor uma arquitetura de fornecimento de suprimentos capaz de garantir uma ICN Indústria de Construção Naval eficaz como um todo e eficiente no Brasil. O estudo parte da identificação e exame dos fatores condicionantes para a estruturação de uma rede de suprimentos, considerando que os recursos disponíveis na indústria podem favorecer a competitividade do todo e a natureza dessa indústria: em fase de reorganização de suas atividades e mobilizada pela entrega de projetos sob encomenda as embarcações. A proposição do framework teórico-conceitual para a estruturação da rede de suprimentos na ICN, com base em princípios colaborativos, parte de um diagnóstico geral da ICN no Brasil, caracterizando a rede de navipeças, realizado por meio de uma pesquisa do tipo survey. Com o resultado das análises, formam-se estratégias para a implantação deste modelo na rede analisada. Para tanto, consideram-se os fatores limitantes e incentivadores do seu processo de estruturação, gerando parâmetros de referência, que podem servir de base à consolidação de uma teoria sucinta sobre a gestão de relacionamentos na cadeia de suprimentos da ICN, ou até sobre o conceito de Supply Chain Management aplicado a indústrias dessa natureza. Espera-se, também, que se proporcione opção de estratégia para as empresas deste setor. / The objective of this study was the consideration of a supply network capable of guaranteeing efficiency within the Brazilian Shipbuilding Industry (ICN Indústria de Construção Naval). The study was conducted under the identification and examination of the conditional factors of the structuring of a supply network, constantly considering that the available resources of the industry can promote the competitiveness of the whole, and the nature of this industry: in phases of reorganizing its activities and mobilized by (the) its made-to-order nature. The proposal of the theoretical-conceptual framework of the supply network structure of the Shipbuilding Industry was conceived on the basis of collaborative principles, initially beginning with a general diagnosis of the industry in Brazil, and then moving into the characterization of the component suppliers by methods of conducted surveys. The analyses pointed to the formulation of strategies for the implementation of this model within the analyzed network. Finally, the strengths and weaknesses of its structuring process were pointed in order to generate references for the consolidation of a plain theory for the relationship management among a network in the Shipbuilding Industry or on the concept of applied Supply Chain Management to this nature of industries, serving as strategical options for the companies of this sector.
17

La pierre et les hommes en Bourgogne : archéologie et histoire d'une ressource en oeuvre du Moyen-Âge à l'époque moderne / Pas de titre en anglais

Foucher, Marion 10 December 2014 (has links)
Pour dépasser les limites inhérentes à la déconnexion des disciplines ou celles imposées par les sources, les périodes ou les sites, cette thèse propose une approche pluridisciplinaire et diachronique de la question de l'approvisionnement en pierre des chantiers médiévaux et modernes. Grâce à la confrontation de bâtiments d'origines et de fonctions différentes, ce travail cherche à décortiquer les processus de choix et réseaux d'approvisionnement en pierre, pour envisager le rapport des hommes à une ressource naturelle. / In order to go further limits inherent to subject disjunction, or those imposed by sources, periods or sites, this thesis emphasises a multidisciplinary and diachronic approach of stone supply on medieval and modern building sites. Thanks to the confrontation of buildings with different origins and functions, this work tries to dissect process of choices and stone supply network. It finally considers connection between people and a natural ressource.
18

Heuristic Mathematical Programming Methods for Lot-sizing, Inventory Control, and Distribution Cost Estimation in the Supply Chain

Samuelsson, Björn January 2017 (has links)
The supply function has an important role to support the business to create a customer value. Two important parts of this process is to have the warehouses and production sites in the right location and to have the right items stocked at the right level.   This thesis is concerned with those two parts of the supply chain management. Three different areas of inventory control are dealt with. In the first part we consider the classical dynamic lot size problem without backlogging. The second part deals with estimation of holding and shortage costs in two-level distribution inventory systems. In the third part of the thesis we consider the localisation problem in a multi-level supply network system where items are consolidated at a warehouse and distributed to customers on routes.   Within the area of inventory control we have evaluated a method earlier suggested by Axsäter (1988), the method is evaluated using a set of test problems and compared other heuristic methods, including the well-known Silver-Meal’s method (Silver and Meal, 1973).  The result shows that the method suggested by Axsäter does perform better than the other methods. In the latest contribution we point to the important differences between Least Period Cost and Silver-Meal when several periods have zero demand. In the area of inventory control we have also studied a two-echelon inventory system where we present methods for estimating the shortage- and stockholding costs in such inventory systems.   The second part subject of the thesis concerns supply network optimization. We present a MIP formulation of the problem and evaluate in detail the approximation of the distribution cost when customers are delivered on multi-stop routes. An improved method for estimating the distribution is presented.   Besides this introductory overview five research papers are included in the thesis. The first and the last paper consider evaluation of dynamic lot sizing heuristics. The second and third paper deals with cost evaluation of a stochastic two-echelon inventory system and the forth paper with evaluation of methods for estimating distribution costs in a supply network.
19

Studie obnovy vybrané části vodovodní sítě / The study of rehabilitation of selected water supply network

Skryja, Marek January 2018 (has links)
This diploma thesis deals with the study of the renewal of a selected part of the water supply network, specifically a section of the steel water supply line near the town of Velké Meziříčí. This study evaluates the current technical condition of the pipeline. Renovation is designed by selected rehabilitation technologies and renewal with the installation of a new pipeline. The thesis also describes the possible substitution of water transport during the shutdown of the part of the water supply network, including the mathematical model. Rehabilitation technologies are compared technically and economically. Also in terms of hydraulic parameters, using the EPANET 2.0 software application.
20

Analýza spotřeby vody ve vodovodní síti Valašského Meziříčí / Assessment of drinking water consumption in the water supply network of the Valašské Meziříčí

Fučík, David January 2019 (has links)
This diploma thesis deals with the analysis of the time series of drains from the water reservoir and evaluation of the minimum night flow in the water supply network of the town of Valašské Meziříčí. In the theoretical part of this thesis were elaborated research of Czech and foreign literature focusing on drinking water consumption analysis, measurement and evaluation of minimum night flow and methods of determination of water losses in distribution systems. The practical part includes analysis of water outflows from reservoirs, evaluation of minimum night flow and determination of basic water loss indicators for selected district metered areas of the network. The above-mentioned water supply network is operated by the Vak Vsetín, a.s.

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