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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.
661

AplicaÃÃo da Teoria dos NÃmeros Fuzzys nos Modelos de Transporte de Poluentes para Avaliar sua Capacidade de PrevisÃo do Risco de ContaminaÃÃo em Rios Naturais / Application of Fuzzy Theory in the Pollutant Transport Models to Evaluate its Capacity of Forecasting the Risk of Contamination in Natural Rivers

Giovanna Salgado da Rocha 29 January 2007 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O estudo da qualidade de Ãgua em corpos hÃdricos, atravÃs de modelagem matemÃtica, tem se tornado um importante caminho no controle e conservaÃÃo dos recursos hÃdricos. Nos dias presentes, com o significativo avanÃo na Ãrea computacional, com computadores de alta velocidade, tem sido possÃvel representar um processo fÃsico qualquer, atravÃs de um modelo matemÃtico com um maior nÃvel de complexidade. Neste sentido, os processos de transporte de poluentes, em rios, estuÃrios ou reservatÃrios tÃm sido representados de forma mais realista, com a ajuda de formulaÃÃes matemÃticas. Por outro lado, a grande parte dos modelos matemÃticos disponÃveis na literatura, dà um tratamento determinÃstico aos estudos de processos fÃsicos. Neste caso, qualquer estudo que necessite de avaliar incerteza ou risco em engenharia, nÃo conseguirà atingir seus objetivos sem um tratamento estocÃstico em suas formulaÃÃes matemÃtica. Este trabalho estuda a aplicaÃÃo da Teoria Fuzzy nos modelos de transporte de poluente para estudar o comportamento das concentraÃÃes de poluentes em rios naturais, atravÃs de funÃÃes de pertinÃncias. O estudo desenvolve uma metodologia, com base nos modelos de transporte fuzzy, e aplica esta metodologia em alguns rios com dados disponÃveis na literatura. Finalmente, o estudo avalia a capacidade desta teoria predizer e avaliar campos de risco fuzzy nestes corpos dâÃgua, mostrando, assim, seu comportamento, no tempo e ao longo do trecho do rio estudado. Os resultados mostram que os modelos fuzzys, aplicados aos processos de transporte de poluentes, podem ser uma boa alternativa na determinaÃÃo do risco de degradaÃÃo de um sistema hÃdrico qualquer. / The study of the water quality in bodies of water, through mathematical modeling has become an important way in the control and conservation of the water resources systems. In the present days, with the significant progress in the computational area, with high-speed computers, it has been possible to represent any physical process, through a mathematical model, with a larger complexity level. In this sense, the transport processes of pollutant, in rivers, estuaries or reservoirs, have been represented in a more realistic way, with the mathematical formulations. On the other hand, the great part of the available mathematical models, in the literature, gives a deterministic treatment to the studies of physical processes. In this case, any study that needs to evaluate uncertainty or engineering risk, it will not get to reach their objectives, without a stochastic treatment in their mathematics formulations. This work studies applications of the Fuzzy Theory in the transport models of pollutant to study the behavior of the concentrations of pollutant in natural rivers, through membership functions. The study develops a methodology, with base in the models of transport fuzzy and it applies this methodology in some rivers with available data. Finally, the study evaluates the capacity of this theory to predict and to calculate fields of risk fuzzy in these bodies of water, showing, like this, its behavior, in the time and along the river. The results show that the fuzzy models, applied to the pollutant transport processes, can be an alternative in the determination of the risk of degradation of any water system.
662

Inteligência práxis: estudo sobre o uso das tecnologias de informação para a gestão da análise do conteúdo de texto / Intelligence Praxis: study on the use of information technologies for the analysis of the management of the content of texts

Melquizedek Fernandes dos Santos 08 February 2017 (has links)
O objetivo deste estudo foi o de apresentar uma nova tecnologia de software especialista, denominada Inteligência Práxis (IP), para a gestão da análise do conteúdo de textos de dissertações, relatórios e indicadores da produção. Este software demonstra através de gráficos lineares e da nuvem de palavras, o foco do texto em análise. Ele também permite a visualização do conteúdo, a partir das palavras contidas no texto e transportadas para um dicionário de dados criado pelas evidências relacionadas, organizando e apresentando para análise do pesquisador o conteúdo proposto como base do conhecimento (Corpus). O software foi implementado em linguagem de programação Delphi, Versão 7 e para armazenamento de dados foi utilizado o banco de dados Absolute Database. A metodologia utilizada para a análise dos dados foi a Metodologia Delphi e a Lógica Fuzzy. Esta tecnologia traz uma inovação na análise do conteúdo dos textos consultados, demonstrando a imagem consolidada do foco do corpus, a partir do dicionário de evidências contidas e pontualmente relacionadas. O mapeamento produzido e a interpretação dos diversos indicadores conduzem a um maior grau de acerto na análise do conteúdo contido no documento, inferindo um melhor entendimento das diversas demandas envolvidas, desveladas pela análise, na expectativa do melhor resultado possível. Assim, pode-se concluir, que a ferramenta desenvolvida atendeu aos objetivos propostos com eficiência e agilidade. / The objective of this study was to present a new specialized software technology, called Intelligence Práxis (IP), for the management of content analysis of dissertations, reports and production indicators. This software demonstrates through linear graphs and the word cloud, the focus of the text under analysis. It also allows the visualization of the content, from the words contained in the text and transported to a data dictionary created by the related evidences, organizing and presenting to the researcher the proposed content as the basis of knowledge (Corpus). The software was implemented in Delphi programming language version 7 and for data storage the Absolute Database was used. The methodology used for the data analysis was the Delphi Methodology and the Fuzzy Logic. This technology brings an innovation in the analysis of the content of the texts consulted, demonstrating the consolidated image of the corpus focus, from the dictionary of contained and punctually related evidences. The mapping produced and the interpretation of the various indicators lead to a greater degree of accuracy in the analysis of the content contained in the document, inferring a better understanding of the diverse demands involved, revealed by the analysis, in the expectation of the best possible result. Thus, it can be concluded that the tool developed met the proposed objectives with efficiency and agility.
663

Indicadores críticos da manufatura de pisos de madeira maciça / Critical indicators applied to manufacture of solid wood flooring

Philipe Ricardo Casemiro Soares 27 January 2010 (has links)
A implementação de programas de qualidade na linha de produção tem sido utilizada por empresas para garantir a competitividade em um mercado cada dia mais competitivo. A busca por equilíbrio entre qualidade e custos é uma constante na área industrial e, neste contexto, melhorias no processo produtivo são fundamentais. No setor florestal, responsável por 3,5% do PIB do país em 2007, a gestão da qualidade aplicada à linha de produção é recente e muitos aspectos importantes não são considerados. O objetivo deste trabalho foi identificar e avaliar os pontos críticos do processo de produção de uma empresa de processamento da madeira. Para tanto, a pesquisa foi dividida em três etapas. A primeira foi o mapeamento do processo da empresa e a elaboração de fluxogramas para as atividades. A segunda fase foi a identificação e avaliação dos pontos críticos por entrevistas com funcionários, utilizando metodologia FMEA (Failure Mode and Effect Analysis) e diagramas de Ishikawa, que relaciona as falhas com suas possíveis causas. A terceira fase foi a avaliação do processo produtivo, empregando o controle estatístico do processo nos principais pontos críticos e a determinação da capacidade do processo pelo índice Cpk. Os resultados mostraram a existência de 6 sub-processos, sendo dois críticos. Nesses setores foram identificados 15 pontos críticos, com cinco deles selecionados para serem avaliados. Os gráficos de controle para variáveis indicaram que o processo produtivo da empresa é instável quanto ao item peças fora de dimensão em ambos setores, enquanto o índice Cpk permitiu concluir que a empresa não é capaz de produzir pisos de madeira dentro das especificações. Para os atributos, o processo era estável, exceto para peças marcadas pela lixa. A causa de não conformidades mais significativa foi a aferição dos equipamentos de medição, que resultou em processos com baixa variação, porém com médias distantes das especificações. / The implementation of quality programs in line production has been used by companies to guarantee the competitiveness in a market more competitive every day. The search for balance between quality and costs is a constant in industrial area and, in this context, improvements in the productive process are fundamentals. In the forest sector, responsible for 3,5% of the countrys GDP in 2007, the quality management applied to the line production is recent and many important aspects are not considered. This study aimed to identify and evaluate the critical points of the process of production of a company of wood processing. Therefore, the research was divided in three stages. The first one was the process mapping of the company and the elaboration of flowcharts for the activities. The second phase was identify and evaluate the critical points for interviews with employees, using FMEA (Failure Mode and Effect Analysis) methodology and Ishikawas diagram, which relates the failure with their possible causes. The third phase was the evaluation of the productive process, applying statistical process control in the main critical points and the determination of the process capability for the Cpk index. The results showed the existence of 6 processes, two of them critical. In those sectors 15 critical points were indentified and 5 were selected for evaluation. The control charts for variables indicated that the process is unstable for the item pieces out of dimension in both processes, while the Cpk index allowed to conclude that the company is not capable to produce wood flooring according to the specifications. For the attributes, the process was stable, except for pieces marked by the sandpaper. The more significant cause of non-conformities was the gauging of the measurement equipments, that resulted in processes with low variation, however with means far from the specifications.
664

Modelo computacional para determinação do risco econômico em culturas irrigadas / Computational model for economical risk determination in irrigated cultures

Patricia Angélica Alves Marques 26 August 2005 (has links)
As empresas agrícolas atuam sob condições de risco, dessa maneira a utilidade de modelos determinísticos para fins de planejamento torna-se relativamente limitada. Isto implica na necessidade de não se desprezar a aleatoriedade de determinados coeficientes e introduzir o risco na análise do projeto. Com este objetivo, desenvolveu-se uma ferramenta na forma de um Modelo Computacional para Determinação do Risco Econômico em Culturas Irrigadas, para o ambiente Windows XP em linguagem Delphi 7.0, que permite simular situações de implantação e manejo da irrigação e suas conseqüências econômicas sob o horizonte de risco. Esse modelo considera, na forma de um projeto, as características agronômicas pertinentes ao solo, a cultura e ao clima, para estudar, de maneira regional, o armazenamento de água no solo, a evapotranspiração, o desenvolvimento da cultura durante as fases fenológicas e o preço de venda do produto. Para atingir o objetivo o modelo realiza simulações dos parâmetros de preço de venda do produto, taxa de manutenção do sistema de irrigação, horas de trabalho necessárias por hectare e por irrigação realizada, preço da água, vida útil do sistema de irrigação e taxa de juros; as quais são classificadas em classes, sendo: cinco classes para vida útil, taxa de manutenção, horas de trabalho necessárias por hectare e por irrigação realizada, preço da água e juros, e 10 classes para o preço de venda do produto. Com esses parâmetros o modelo computacional gera 31.250 valores de benefícios líquidos anuais combinados das classes com suas respectivas probabilidades de ocorrência, permitindo assim um estudo probabilístico dos possíveis resultados da decisão de aquisição do sistema de irrigação. Como resultados essa ferramenta simula e fornece a distribuição de probabilidades dos fatores econômicos e calcula os custos fixos, custos variáveis, custos totais e benefícios líquidos anuais da irrigação. Com os 31.250 valores de benefícios líquidos anuais e suas probabilidades realiza o teste de aderência às funções de densidade de probabilidade normal ou triangular e posteriormente exibe as probabilidades de viabilidade do projeto, a relação benefício/custo, valor esperado de benefício líquido, desvio absoluto, variância, desvio padrão e coeficiente de variação como índices econômicos envolvidos na decisão de irrigar ou não irrigar. Apresenta também uma análise de sensibilidade do benefício líquido anual em função da variação dos fatores econômicos e a participação em porcentagem dos fatores econômicos na formação do custo total da irrigação. Nas análises realizadas sobre a irrigação da cana-de-açúcar para região de Piracicaba, todos os sistemas testados apresentaram relação benefício/custo inferior a um e valores esperados de benefício líquido anual da irrigação negativos, indicando inviabilidade. A utilização do motor diesel apresentou para todos os sistemas, probabilidade nula de ocorrência de benefício líquido anual maior que zero. Dentre os sistemas analisados o pivô central apresentou a maior probabilidade de ocorrência de benefício líquido anual maior que zero (10,70%) utilizando energia elétrica. No caso da irrigação do tomate industrial na região de Piracicaba todos os sistemas testados apresentaram viabilidade, isto é, relação benefício/custo sempre maior que um e valores esperados de benefício líquido anual positivos. Dentre eles a aspersão convencional apresentou a maior relação benefício/custo (média de 4,74), o maior valor esperado de benefício líquido anual (R$ 1.582,60 ha-1 ano-1) e o menor risco com um desvio padrão de R$ 363,99 ha-1 ano-1. / The agricultural companies were submitted to risky conditions, so the utility of deterministic models to planning is relatively limited. That implies in not despise the randomness of some coefficients and to introduce them in the project analysis. As a proposal of this work a Computational model for risk determination in irrigated cultures was elaborated for Windows XP® in Delphi 7.0 language, that allow the simulation of implanting and managing irrigations projects and their economical consequences under the risk conditions. This model considers, in a project form, the agronomical characteristics of the soil, of the culture and of the climate, to study, regionally, the water storage in the soil, the evapotranspiration, the culture development during the phenological phases and the selling price of the product. To reach its objectives the model accomplishes simulations in the selling price of the product, maintaining cost of the irrigation system, hours of needed work by hectare and per irrigation, water cost, useful life of the system and the welfare taxes, that were classified in classes as: five for useful live, maintain tax, hours of needed work by hectare and per irrigation, water cost and welfare taxes; and ten for selling price. With those parameters the model generated 31,250 values of annual combined liquid profits of the classes with their respective probability of occurrence, allowing a probabilistic study of the possible results in the acquisition of an irrigation system, e.g., the probability of the project viability. This tool, as its results, simulates and displays the economical factor probability and calculates the variable and the non variable costs, total costs and annual profits of irrigation. With the 31,250 values of annual profits and their probabilities, it realizes the adherence test to the density functions of normal or triangular probability and exhibits the project viability probabilities, cost/profit relation, expected value of liquid profit, absolute deviance, variance, standard deviation and coefficient of variation as economical indexes involved in the decision of or not of to irrigate. It also presents a sensibility analysis of the annual profit as a function of the economical variation factors and the participation, in percentage, of those factors in the total cost of the irrigation. In the analysis of sugarcane irrigation in the Piracicaba region, all tested systems showed a cost/profit relation inferior to one and expected annual irrigation profit values negative indicating the inviability. The use of a diesel motor, for any system, showed the null probability of the annual profit to be higher then zero. Among the tested systems the center pivot showed the highest probability of annual liquid profits higher then zero (10.7%) using electrical energy. In the case of tomato culture for industry under irrigation, in the Piracicaba region, all systems were viable, e.g., the relation cost/profit ever higher then one and expected values of annual liquid profits positive. Among them the conventional aspersion showed the higher relation between cost/profit with a mean of 4.74, the highest expected value of annual liquid profit of R$ 1,582.60 ha-1 year-1 and with the lower risk with standard deviation of R$ 363.99 ha-1 year-1.
665

Mitigação de incertezas atraves da integração com ajuste de historico de produção / Uncertainty mitigation through the integration with production history matching

Becerra, Gustavo Gabriel 12 July 2007 (has links)
Orientadores: Denis Jose Schiozer, Celio Maschio / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica e Instituto de Geociencias / Made available in DSpace on 2018-08-12T07:35:35Z (GMT). No. of bitstreams: 1 Becerra_GustavoGabriel_M.pdf: 16760750 bytes, checksum: 0609c24d13d46b9121f71356ce9d42a1 (MD5) Previous issue date: 2007 / Resumo: A escassez de informações de qualidade introduz risco ao processo de previsão da produção de petróleo tornando imprescindível o ajuste de histórico de produção, que é a calibração do modelo a partir da resposta produtiva registrada. O ajuste é um problema inverso, em que diferentes combinações dos valores dos parâmetros do reservatório podem conduzir a respostas aceitáveis, especialmente quando o grau de incerteza desses parâmetros é elevado. A integração do ajuste de histórico com a análise probabilística dos cenários representativos conduz à obtenção de uma metodologia para detecção dos modelos calibrados dentro de uma faixa de aceitaçãodefinida. O tratamento de atributos interdependentes de influência global e local e o avanço por etapas são necessários. Desta forma, o objetivo deste trabalho é apresentar uma metodologia que integra a análise de incertezas com o ajuste de histórico em modelos de reservatórios complexos. Este procedimento auxilia a detectar os atributos incertos críticos e sua possível variação com o intuito de estimar a faixa representativa das reservas a desenvolver. Não é alvo obter o melhor ajuste determinístico, mas refletir como o histórico possibilita uma mitigação das incertezas. Assim, a meta é usar modelos mais complexos e aprimorar a metodologia iniciada por Moura Filho (2006), desenvolvida para um modelo teórico simples. São utilizados dois casos de estudo de complexidade similar. Um deles referente ao reservatório do Campo de Namorado, utilizado para verificar e validar, em nível global, a aplicação da metodologia. Na etapa de aplicação, é usado um modelo sintético construído a partir de dados de afloramentos reais no Brasil e compreendendo informações de campos análogos com sistemas turbidíticos depositados em águas profundas. Os métodos aplicados, mediante a redefinição das probabilidades associadas e níveis dos atributos incertos, permitem: (1) reduzir a faixa de ajustes possíveis e obter modelos mais confiáveis; (2) identificar e condicionar à incerteza presente em função dos dados registrados; (3) diminuir os intervalos de incerteza dos parâmetros críticos identificados; (4) demarcar os limites seguros do desempenho futuro do reservatório. A conseqüência é um aumento da confiança no uso da simulação como ferramenta auxiliar do processo decisório. Além disso, procura-se fornecer à equipe multidisciplinar uma metodologia para reduzir o tempo empregado no gerenciamento de múltiplos atributos incertos na etapa de ajuste do modelo. / Abstract: The lack of reliable data or with high degree of uncertainty yields risk to the process of production prediction making the history matching, the model calibration from the registered field production indispensable. History matching is an inverse problem and, in general, different combinations of reservoir attributes can lead acceptable solutions, especially whit high degree of uncertainty of these attributes. The integration of history matching with a probabilistic analysis of representative models yields a way to detect matched models inside an acceptance interval, providing more efficient framework for predictions. It is necessary to consider dependences between global and local attributes. The scope of this work is to present a methodology that integrates the uncertainty analysis with the history matching process in complex models. This procedure helps to detect critical subsurface attributes and their possible variation, in order to estimate a representative range of the additional reserves to be developed. . It is not an objective to obtain the best deterministic model, but to mitigate uncertainties by using observed data. The objective is to improve the methodology initiated by Moura Filho (2006), applied to a simple model. The methodology presented in this work is applied in two study cases with similar complexity. Firstly, the methodology is verified and validated, on global scale, in Namorado Field. Then, at the application stage, it is chosen a synthetic reservoir model made from real outcrop data of Brazil and involving information from analog fields with turbiditic systems deposited in deep waters. The methodology allows the redefinition of the probability and levels of the dynamic and static attributes in order: (1) to reduce the group of possible history matching obtaining more realistic models; (2) to identify the existent uncertainty as a function of observed data; (3) to decrease the uncertainty range of critical reservoir parameters; (4) to increase the confidence in production forecast. One contribution of this work is to present a quantitative approach to increase the reliability on the use of reservoir simulation as an auxiliary tool in decision processes. Another purpose of this work is to provide a procedure to reduce the consumed time to handle multiples uncertainty attributes during the history matching. / Mestrado / Reservatórios e Gestão / Mestre em Ciências e Engenharia de Petróleo
666

How companies manage IT security : A comparative study of Pakistan and Sweden

Qureshi, Mustafa Ali, Khalid, Farhan January 2013 (has links)
IT security provides comprehensive picture both internally and externally by act of ensuring that data is not lost when critical issues arise. In spite of the world has now been replaced with an imperative approach. The companies are using widely desktop computers, laptops, ipads, smart phones and workstation. The sum of all this has been influence to the IT based information and communication system in companies.   The purpose is to do research by taking a critical look at how different kind of business and non-business companies manage their IT security in Pakistan and Sweden with specific emphasis on the administrative controls. As the IT security has a list of steps but the authors focused on three major functions: IT security policy, IT security plan and IT security risk analysis.   As soon as the topic was selected the emphasis was laid on collecting and reading material related to the IT security. It became clear that the most relevant and interesting task was not merely to investigate how different companies in Pakistan and Sweden manage their IT security but infact try to understand what kind of steps and measures lies behind to achieve them. The method was adopted qualitative because it fulfil the requirements which authors want to achieve in the form of deeper understanding how different companies manage IT security in two different countries.   This study concluded that Pakistani companies in terms of IT security policy should focus on data ware houses by implementing policies for securing of exploiting the data and in case of Swedish company IT managers should implement policies for securing of personal data. Evaluation techniques are missing from the companies of Pakistan and Sweden in IT security plan. Enhancing the performing of IT risk analysis to countermeasure the threat. Pakistani companies should focus on business model of information asset. In case of Swedish company higher level and more detailed analysis can apply to core areas of the IT system. These proposed points for improvements could also help in more understanding of IT security in Pakistan and Sweden.
667

Návrh projektu a aplikace metodiky projektového managementu v podniku / Project Design and Application of Methodology of Project Management in the Company

Entlová, Radka January 2013 (has links)
The master’s thesis considers a project proposal for development of application software for customer’s needs. The thesis specifies the basic concepts and methods of project management. It contains analysis of the current state of company and its environment. The thesis focuses on the project proposal.
668

Projektové řízení ve společnosti Hella Autotechnik Nova, s. r. o / Project Management in the Company Hella Autotechnik Nova, s. r. o

Bílek, Pavel January 2015 (has links)
The master´s thesis deals with the problems of project management. Specifically, it deals with analysis of current state and draft measures for project management at company Hella Autotechnik Nova, s. r. o, which is necessary to optimizing for management of development projects in company technical centre. The thesis uses mainly procedures and project management methods defined by the PMI (Project Management Institute).
669

A two-level Probabilistic Risk Assessment of cascading failures leading to blackout in transmission power systems

Henneaux, Pierre 19 September 2013 (has links)
In our society, private and industrial activities increasingly rest on the implicit assumption that electricity is available at any time and at an affordable price. Even if operational data and feedback from the electrical sector is very positive, a residual risk of blackout or undesired load shedding in critical zones remains. The occurrence of such a situation is likely to entail major direct and indirect economical consequences, as observed in recent blackouts. Assessing this residual risk and identifying scenarios likely to lead to these feared situations is crucial to control and optimally reduce this risk of blackout or major system disturbance. The objective of this PhD thesis is to develop a methodology able to reveal scenarios leading to a blackout or a major system disturbance and to estimate their frequencies and their consequences with a satisfactory accuracy.<p><p>A blackout is a collapse of the electrical grid on a large area, leading to a power cutoff, and is due to a cascading failure. Such a cascade is composed of two phases: a slow cascade, starting with the occurrence of an initiating event and displaying characteristic times between successive events from minutes to hours, and a fast cascade, displaying characteristic times between successive events from milliseconds to tens of seconds. In cascading failures, there is a strong coupling between events: the loss of an element increases the stress on other elements and, hence, the probability to have another failure. It appears that probabilistic methods proposed previously do not consider correctly these dependencies between failures, mainly because the two very different phases are analyzed with the same model. Thus, there is a need to develop a conceptually satisfying probabilistic approach, able to take into account all kinds of dependencies, by using different models for the slow and the fast cascades. This is the aim of this PhD thesis.<p><p>This work first focuses on the level-I which is the analysis of the slow cascade progression up to the transition to the fast cascade. We propose to adapt dynamic reliability, an integrated approach of Probabilistic Risk Analysis (PRA) developed initially for the nuclear sector, to the case of transmission power systems. This methodology will account for the double interaction between power system dynamics and state transitions of the grid elements. This PhD thesis also introduces the development of the level-II to analyze the fast cascade, up to the transition towards an operational state with load shedding or a blackout. The proposed method is applied to two test systems. Results show that thermal effects can play an important role in cascading failures, during the first phase. They also show that the level-II analysis after the level-I is necessary to have an estimation of the loss of supplied power that a scenario can lead to: two types of level-I scenarios with a similar frequency can induce very different risks (in terms of loss of supplied power) and blackout frequencies. The level-III, i.e. the restoration process analysis, is however needed to have an estimation of the risk in terms of loss of supplied energy. This PhD thesis also presents several perspectives to improve the approach in order to scale up applications to real grids.<p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished
670

Optimisation de l’aménagement d’un Chantier de Construction en Fonction des Risques Naturels et Technologiques, Utilisation du SIG / Construction Site Layout Optimization, Considering Risk of Natural or Technological Hazard Utilizing GIS

Abune'meh, Mohammed 24 May 2017 (has links)
Les chantiers de construction contiennent plusieurs installations. Celles-ci sont susceptibles d’être endommagées par des incidents liés aux risques naturels ou technologiques comme les incendies, les explosions, les ondes de souffles, etc. Ces incidents peuvent avoir des conséquences néfastes sur l’ensemble du processus de construction, ce qui pourrait entrainer des accidents graves ayant un impact majeur sur la productivité des employés, le temps global du projet, sa qualité et son budget. Par conséquent les gestionnaires et les planificateurs du projet doivent adopter et développer des approches novatrices capables de faire face aux risques naturels potentiels, de minimiser leurs conséquences et de faciliter l’évacuation du site en cas de danger. Une de ces approches consiste à optimiser l’aménagement des chantiers de construction. En général, la réduction des dommages résultants de risques naturels ou technologiques est encore un défi scientifique.Dans cette thèse, deux modèles (déterministe et probabiliste) sont développés pour minimiser les risques au sein d’un chantier. La méthode adoptée pour le développement de ces deux modèles consiste en :• La modélisation des éléments du chantier, par exemple : le générateur électrique, les bureaux et les entrepôts de matériaux, sont modélisés en 2D, pour agir en tant que source d’aléa et/ou cible vulnérable potentielle.• La modélisation de l’aléa : elle montre l’interaction des aléas entre les composants du chantier.• La modélisation de la vulnérabilité : elle représente la faiblesse potentielle des cibles sur l’aléa généré par chaque source.• La définition de la fonction d’utilité : elle vise à offrir une disposition optimisée avec un minimum de risque total sur le chantier. L’algorithme à évolution différentielle est adopté pour exécuter le processus d’optimisation.D’une part, dans le modèle déterministe, nous utilisons le principe de la syntaxe spatiale pour étudier l’impact des configurations spatiales dans l’évaluation du risque sur le chantier. Par conséquent, comme le processus d’évacuation est pris en compte dans l’estimation du risque, le risque réel est amplifié en utilisant le facteur de pénalité appelé « profondeur moyenne ». L’algorithme de Dijkstra est appliqué sur un modèle déterministe afin de trouver les chemins les plus sûrs (chemins de moindre risque) pour évacuer les sites à partir de chaque position sur le chantier vers les lieux sûrs afin de diminuer les pertes humaines et matérielles.D’autre part, le modèle probabiliste suppose que le risque est composé de la défaillance individuelle de chaque installation sur le chantier de construction. La simulation numérique est utilisée pour trouver la distribution de probabilités des défaillances pour l’ensemble du site.Les fonctionnalités d’un SIG (Système d’Information Géographique) ont été utilisées pour présenter les données sous forme de cartes, pour produire des cartes spatiales de risque sur le chantier de construction, pour mettre en œuvre l’algorithme de Dijkastra et pour l’analyse du coût le plus faible.A titre indicatif, les modèles proposés sont utilisés dans un cas d’étude comprenant plusieurs installations. Dans le modèle déterministe, toutes ces installations agissent comme des sources d’aléa et des cibles vulnérables, en même temps, dans le modèle probabiliste, quelques-unes de ces installations agissent comme des sources d’aléa et toutes comme des cibles vulnérables. Les résultats obtenus montrent que les modèles proposés sont efficaces en raison de leur capacité à générer une disposition optimale du site avec un environnement de travail plus sûr. En outre, les modèles obtenus sont capables de mettre en évidence les zones les plus risquées d’un chantier, de générer les chemins d’évacuation les moins risqués, ce qui permettra de minimiser les blessures graves et les victimes en cas d’urgence / Construction sites contain several supporting facilities that are required to complete construction activities. These facilities are susceptible to damage due to the occurrence of natural or technological hazards such as fire, explosion, blast wave, and so on. These may cause adverse consequences for the whole construction process, which in turn lead to fatal accidents that have a major impact on worker and employee productivity, project completion time, project quality and project budget. Therefore, project planners must adopt and develop innovative approaches able to face the occurrence of potential hazards, minimize their consequences, and facilitate the evacuation of the site in case of their occurrence. One of these approaches is optimizing construction site layout. In general, generating construction site layout able minimizing risk resulting from natural or technological hazards is still a scientific challenge.In the present research, two proposed model (deterministic and probabilistic) are developed to minimize the risks within a construction site. The common methodology adopted to develop these two models consists of:• Modeling construction site components, for instance; electric generator, offices and material storages, in a 2D layout, to act as either hazardous source or potential target or both at the same time.• Modeling hazard: it shows the hazard interaction among site components and the attenuation of hazard.• Modeling vulnerability: it represents the potential weakness of whole targets to the hazard generated from each source.• Defining the utility function: it aims to afford an optimized site layout with minimum total risk in the construction site. The differential evolution algorithm is adopted to run optimization process.Particularly, in the deterministic model, we use space syntax principle in order to realize the impact of space configurations in evaluating the risk in the construction site. Therefore, as the evacuation process is considered in estimating the risk, the actual risk is amplified by utilizing penalty factor called mean depth. Furthermore, Dijkstra’s algorithm is run on deterministic model to find the safest paths (least risk paths) for evacuating sites from any position on the construction site towards the safe places in order to diminish losses and fatalities. On the other hand, the framework utilized to develop a probabilistic model assumed that the risk is combined of the individual failure of each facility within a construction site. Moreover, the numerical simulation is performed to find the probabilistic distribution of failure for the whole site.Geographic information system (GIS) capabilities were exploited, in this research, to present data in maps format, generate the spatial risk map in the construction site, and implement the Dijkstra’s algorithm and least-cost path analysis.For illustration purposes, the proposed models are employed in a case study consisting of several facilities. In the deterministic model, all of these facilities act as hazardous sources and potential targets, at the same time, while, in a probabilistic model, only three of these facilities act as fire hazardous sources, whereas, all of them are potential targets. The results revealed that the proposed models are efficient due to their capability of generating site layout with the safer work environment. In addition, the model is capable of highlighting the riskiest areas within a construction site. Moreover, the proposed models are able to generate paths through least-risk zones, which will minimize the serious injuries and victims in cases of emergencies

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