993 resultados para Local variables
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In this paper we address the real-time capabilities of P-NET, which is a multi-master fieldbus standard based on a virtual token passing scheme. We show how P-NET’s medium access control (MAC) protocol is able to guarantee a bounded access time to message requests. We then propose a model for implementing fixed prioritybased dispatching mechanisms at each master’s application level. In this way, we diminish the impact of the first-come-first-served (FCFS) policy that P-NET uses at the data link layer. The proposed model rises several issues well known within the real-time systems community: message release jitter; pre-run-time schedulability analysis in non pre-emptive contexts; non-independence of tasks at the application level. We identify these issues in the proposed model and show how results available for priority-based task dispatching can be adapted to encompass priority-based message dispatching in P-NET networks.
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Dissertação de mestrado em Ciências da Educação: área de Educação e Desenvolvimento
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Dissertação de mestrado em Ciências da Educação: área de Educação e Desenvolvimento
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Dissertação de mestrado em Ciências da Educação: área de Educação e Desenvolvimento
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The basic motivation of this work was the integration of biophysical models within the interval constraints framework for decision support. Comparing the major features of biophysical models with the expressive power of the existing interval constraints framework, it was clear that the most important inadequacy was related with the representation of differential equations. System dynamics is often modelled through differential equations but there was no way of expressing a differential equation as a constraint and integrate it within the constraints framework. Consequently, the goal of this work is focussed on the integration of ordinary differential equations within the interval constraints framework, which for this purpose is extended with the new formalism of Constraint Satisfaction Differential Problems. Such framework allows the specification of ordinary differential equations, together with related information, by means of constraints, and provides efficient propagation techniques for pruning the domains of their variables. This enabled the integration of all such information in a single constraint whose variables may subsequently be used in other constraints of the model. The specific method used for pruning its variable domains can then be combined with the pruning methods associated with the other constraints in an overall propagation algorithm for reducing the bounds of all model variables. The application of the constraint propagation algorithm for pruning the variable domains, that is, the enforcement of local-consistency, turned out to be insufficient to support decision in practical problems that include differential equations. The domain pruning achieved is not, in general, sufficient to allow safe decisions and the main reason derives from the non-linearity of the differential equations. Consequently, a complementary goal of this work proposes a new strong consistency criterion, Global Hull-consistency, particularly suited to decision support with differential models, by presenting an adequate trade-of between domain pruning and computational effort. Several alternative algorithms are proposed for enforcing Global Hull-consistency and, due to their complexity, an effort was made to provide implementations able to supply any-time pruning results. Since the consistency criterion is dependent on the existence of canonical solutions, it is proposed a local search approach that can be integrated with constraint propagation in continuous domains and, in particular, with the enforcing algorithms for anticipating the finding of canonical solutions. The last goal of this work is the validation of the approach as an important contribution for the integration of biophysical models within decision support. Consequently, a prototype application that integrated all the proposed extensions to the interval constraints framework is developed and used for solving problems in different biophysical domains.
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As práticas de gestão ambiental são meios através dos quais as organizações podem melhorar o seu desempenho. Um comportamento eco-eficiente, optimiza o uso dos recursos e evita a produção de resíduos, permitindo poupanças significativas. Para além disso, um bom desempenho ambiental evita custos resultantes da aplicação do princípio do poluidor-pagador. A introdução destas práticas no processo de gestão global é hoje uma realidade nas empresas. No entanto, e como muitas das acções a nível local passam essencialmente pelas autarquias, afigura-se fundamental que também estas organizações introduzam práticas ambientais na sua gestão. O objectivo central deste trabalho é identificar o perfil ambiental da Administração Pública Local, nomeadamente dos municípios portugueses. Para atingir este objectivo foi desenvolvido um inquérito por questionário, o qual foi remetido a todos os municípios do país, de forma a poder diagnosticar práticas de gestão ambiental nesse sector. Com base na avaliação do grau de implementação de determinadas vertentes e práticas de gestão ambiental foi traçado o perfil ambiental dos municípios portugueses. Os principais resultados evidenciam um fraco nível de adopção de práticas de gestão ambiental. Urge melhorar estes níveis de desempenho, pelo que deverão ser adoptadas novas práticas organizacionais e políticas públicas de desenvolvimento sustentável, para que se inverta a tendência actual. Este trabalho pretendeu constituir uma base de apoio às inúmeras autarquias, transmitindo quais as vantagens de recorrer a práticas de gestão ambiental, de forma a aumentar o desempenho ambiental nestas organizações.
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The influence of uncertainties of input parameters on output response of composite structures is investigated in this paper. In particular, the effects of deviations in mechanical properties, ply angles, ply thickness and on applied loads are studied. The uncertainty propagation and the importance measure of input parameters are analysed using three different approaches: a first-order local method, a Global Sensitivity Analysis (GSA) supported by a variance-based method and an extension of local variance to estimate the global variance over the domain of inputs. Sample results are shown for a shell composite laminated structure built with different composite systems including multi-materials. The importance measures of input parameters on structural response based on numerical results are established and discussed as a function of the anisotropy of composite materials. Needs for global variance methods are discussed by comparing the results obtained from different proposed methodologies. The objective of this paper is to contribute for the use of GSA techniques together with low expensive local importance measures.
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OBJETIVO : Descrever as refeições realizadas por adultos quanto ao local e tipo de preparação consumido em cidade de médio porte, do sul do Brasil. MÉTODOS : Estudo transversal, de base populacional, na cidade de Pelotas, RS, em 2012. A amostragem foi realizada em dois estágios, tendo os setores censitários do Censo Demográfico de 2010 como unidade amostral primária. Foram coletadas informações sobre o local das refeições (em casa ou fora de casa) e sobre o tipo de preparação consumida em casa (comida caseira, lanches, comida de restaurante) nos dois dias prévios à entrevista, utilizando-se questionário padronizado. RESULTADOS : Participaram do estudo 2.927 adultos: 59,0% mulheres, 60,0% com idade abaixo de 50 anos e 58,0% estava trabalhando. Foram obtidas informações sobre 11.581 refeições nos dois dias anteriores à entrevista, sendo 25,0% delas realizadas fora de casa, no almoço, e 10,0% no jantar. Quanto às refeições realizadas em casa, a maioria dos participantes referiu ter consumido comida preparada em casa, tanto no almoço quanto no jantar. A maioria das refeições fora de casa (64,0% no almoço e 61,0% no jantar) foram realizadas no local de trabalho, majoritariamente preparadas em casa. As refeições fora de casa foram realizadas principalmente por pessoas do sexo masculino, jovens, com alta escolaridade. Quanto à ocupação, os grupos que tiveram refeições mais frequentemente em restaurantes foram trabalhadores do comércio, empresários, professores e profissionais de nível superior. CONCLUSÕES : Apesar das mudanças que vêm sendo registradas nos padrões de alimentação do brasileiro, adultos residentes em cidades de médio porte ainda se alimentam majoritariamente em casa e de comida caseira.
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OBJECTIVE To analyze the dynamics of operation of the Bipartite Committees in health care in the Brazilian states.METHODS The research included visits to 24 states, direct observation, document analysis, and performance of semi-structured interviews with state and local leaders. The characterization of each committee was performed between 2007 and 2010, and four dimensions were considered: (i) level of institutionality, classified as advanced, intermediate, or incipient; (ii) agenda of intergovernmental negotiations, classified as diversified/restricted, adapted/not adapted to the reality of each state, and shared/unshared between the state and municipalities; (iii) political processes, considering the character and scope of intergovernmental relations; and (iv) capacity of operation, assessed as high, moderate, or low.RESULTS Ten committees had advanced level of institutionality. The agenda of the negotiations was diversified in all states, and most of them were adapted to the state reality. However, one-third of the committees showed power inequalities between the government levels. Cooperative and interactive intergovernmental relations predominated in 54.0% of the states. The level of institutionality, scope of negotiations, and political processes influenced Bipartite Committees’ ability to formulate policies and coordinate health care at the federal level. Bipartite Committees with a high capacity of operation predominated in the South and Southeast regions, while those with a low capacity of operations predominated in the North and Northeast.CONCLUSIONS The regional differences in operation among Bipartite Interagency Committees suggest the influence of historical-structural variables (socioeconomic development, geographic barriers, characteristics of the health care system) in their capacity of intergovernmental health care management. However, structural problems can be overcome in some states through institutional and political changes. The creation of federal investments, varied by regions and states, is critical in overcoming the structural inequalities that affect political institutions. The operation of Bipartite Committees is a step forward; however, strengthening their ability to coordinate health care is crucial in the regional organization of the health care system in the Brazilian states.
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Solving systems of nonlinear equations is a very important task since the problems emerge mostly through the mathematical modelling of real problems that arise naturally in many branches of engineering and in the physical sciences. The problem can be naturally reformulated as a global optimization problem. In this paper, we show that a self-adaptive combination of a metaheuristic with a classical local search method is able to converge to some difficult problems that are not solved by Newton-type methods.
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OBJECTIVE To analyze the factors associated with a lack of prenatal care in a large municipality in southern Brazil. METHODS In this case-control age-matched study, 716 women were evaluated; of these, 179 did not receive prenatal care and 537 received prenatal care (controls). These women were identified using the Sistema Nacional de Informação sobre Nascidos Vivos (Live Birth Information System) of Pelotas, RS, Southern Brazil, between 2009 and 2010. Multivariate analysis was performed using conditional logistic regression to estimate the odds ratios (OR). RESULTS In the final model, the variables associated with a lack of prenatal care were the level of education, particularly when it was lesser than four years [OR 4.46; 95% confidence interval (CI) 1.92;10.36], being single (OR 3.61; 95%CI 1.85;7.04), and multiparity (OR 2.89; 95%CI 1.72;4.85). The prevalence of a lack of prenatal care among administrative regions varied between 0.7% and 3.9%. CONCLUSIONS The risk factors identified must be considered when planning actions for the inclusion of women in prenatal care by both the central management and healthcare teams. These indicated the municipal areas with greater deficits in prenatal care. The reorganization of the actions to identify women with risk factors in the community can be considered to be a starting point of this process. In addition, the integration of the activities of local programs that target the mother and child is essential to constantly identify pregnant women without prenatal care.
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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Ordenamento do Território e Planeamento Ambiental
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This paper presents a methodology for applying scheduling algorithms using Monte Carlo simulation. The methodology is based on a decision support system (DSS). The proposed methodology combines a genetic algorithm with a new local search using Monte Carlo Method. The methodology is applied to the job shop scheduling problem (JSSP). The JSSP is a difficult problem in combinatorial optimization for which extensive investigation has been devoted to the development of efficient algorithms. The methodology is tested on a set of standard instances taken from the literature and compared with others. The computation results validate the effectiveness of the proposed methodology. The DSS developed can be utilized in a common industrial or construction environment.
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ABSTRACT OBJECTIVE: To analyze whether sociodemographic characteristics, consultations and care in special services are associated with scheduled infectious diseases appointments missed by people living with HIV. METHODS: This cross-sectional and analytical study included 3,075 people living with HIV who had at least one scheduled appointment with an infectologist at a specialized health unit in 2007. A secondary data base from the Hospital Management & Information System was used. The outcome variable was missing a scheduled medical appointment. The independent variables were sex, age, appointments in specialized and available disciplines, hospitalizations at the Central Institute of the Clinical Hospital at the Faculdade de Medicina of the Universidade de São Paulo, antiretroviral treatment and change of infectologist. Crude and multiple association analysis were performed among the variables, with a statistical significance of p ≤ 0.05. RESULTS: More than a third (38.9%) of the patients missed at least one of their scheduled infectious diseases appointments; 70.0% of the patients were male. The rate of missed appointments was 13.9%, albeit with no observed association between sex and absences. Age was inversely associated to missed appointment. Not undertaking anti-retroviral treatment, having unscheduled infectious diseases consultations or social services care and being hospitalized at the Central Institute were directly associated to missed appointments. CONCLUSIONS: The Hospital Management & Information System proved to be a useful tool for developing indicators related to the quality of health care of people living with HIV. Other informational systems, which are often developed for administrative purposes, can also be useful for local and regional management and for evaluating the quality of care provided for patients living with HIV.
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This papers aims at providing a combined strategy for solving systems of equalities and inequalities. The combined strategy uses two types of steps: a global search step and a local search step. The global step relies on a tabu search heuristic and the local step uses a deterministic search known as Hooke and Jeeves. The choice of step, at each iteration, is based on the level of reduction of the l2-norm of the error function observed in the equivalent system of equations, compared with the previous iteration.