49 resultados para Problema de Riemann com restrição

em Universidade Federal do Rio Grande do Norte(UFRN)


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This work proposes a computational methodology to solve problems of optimization in structural design. The application develops, implements and integrates methods for structural analysis, geometric modeling, design sensitivity analysis and optimization. So, the optimum design problem is particularized for plane stress case, with the objective to minimize the structural mass subject to a stress criterion. Notice that, these constraints must be evaluated at a series of discrete points, whose distribution should be dense enough in order to minimize the chance of any significant constraint violation between specified points. Therefore, the local stress constraints are transformed into a global stress measure reducing the computational cost in deriving the optimal shape design. The problem is approximated by Finite Element Method using Lagrangian triangular elements with six nodes, and use a automatic mesh generation with a mesh quality criterion of geometric element. The geometric modeling, i.e., the contour is defined by parametric curves of type B-splines, these curves hold suitable characteristics to implement the Shape Optimization Method, that uses the key points like design variables to determine the solution of minimum problem. A reliable tool for design sensitivity analysis is a prerequisite for performing interactive structural design, synthesis and optimization. General expressions for design sensitivity analysis are derived with respect to key points of B-splines. The method of design sensitivity analysis used is the adjoin approach and the analytical method. The formulation of the optimization problem applies the Augmented Lagrangian Method, which convert an optimization problem constrained problem in an unconstrained. The solution of the Augmented Lagrangian function is achieved by determining the analysis of sensitivity. Therefore, the optimization problem reduces to the solution of a sequence of problems with lateral limits constraints, which is solved by the Memoryless Quasi-Newton Method It is demonstrated by several examples that this new approach of analytical design sensitivity analysis of integrated shape design optimization with a global stress criterion purpose is computationally efficient

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Nowadays, in the plastic industry are used mills that accomplish the recycling of residues generated in the production of its components. These mills contain cut sheets that suffer accelerated wear, once they are submitted constantly to the tribologic efforts, decreasing its useful life. To reduce this problem, it s used noble steels or takes place superficial treatments. The ionic nitriding process presents some limitations related to the uniformity of the layer in pieces with complex geometry, committing its application in pieces as knives, head offices, engagements, etc. However, the new technique of nitriding in cathodic cage eliminates some problems, as the restrictions rings, inherent to the conventional ionic nitriding. In present work, was studied the use viabilization of steels less noble, as SAE 1020, SAE 4320 and SAE 4340, nitreded by two different techniques, to substitute the AISI 01 steels, usually used in the cut knifes fabrication, seeking to reduce the costs and at the sane time to increase the useful life of these knifes. The steel most viable was the SAE 4340, nitrided in cathodic cage, because it presented uniformity in thickness and in the hardness of the layer, besides of increased 58% in the average its useful life

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Hereditary Hemochromatosis (HH) is a genetic disease caused by high iron absorption and deposition in several organs. This accumulation results in clinical disturbances such as cirrhosis, arthritis, cardiopathies, diabetes, sexual disorders and skin darkening. The H63D and C282Y mutations are well defined in the hemochromatosis etiology. The aim of this paper was that of identifying the H63D and C282Y genetical mutations in the hemochromatosis gene and the frequency assessment of these mutations in the HFE protein gene in patients with hyperferritin which are sent to the DNA Center laboratory in Natal, state of Rio Grande do Norte. This paper also evaluates the HH H63D and C282Y gene mutations genotype correlation with the serum ferritin concentration, glucose, alanine aminotransferasis, aspartato aminotransferasis, gama glutamil transferasis and with the clinical complications and also the interrelation with life habits including alcoholism and iron overload. The biochemical dosages and molecule analyses are done respectively by the enzymatic method and PCR with enzymatic restriction. Out of the 183 patients investigated, 51,4% showed no mutation and 48,6% showed some type of mutation: 5,0% were C282Y heterozygous mutation; 1,1%, C282Y homozygous mutation; 31%, H63D heterozygous mutation; 8,7%, H63D homozygous mutation; and 3,3%, heterozygous for the mutation in both genes. As to gender, we observed a greater percentage of cases with molecular alteration in men in relation to women in the two evaluated mutations. The individuals with negative results showed clinical and lab signs which indicate hemochromatosis that other genes could be involved in the iron metabolism. Due to the high prevalence of hemochromatosis and taking into account that hemochromatosis is considered a public health matter, its gravity being preventable and the loss treatment toxicity, the early genetic diagnosis is indicated, especially in patients with high ferritin, and this way it avoids serious clinical manifestations and increases patients' life expectation. Our findings show the importance of doing such genetic studies in individuals suspected of hereditary hemochromatosis due to the high incidence of such a hereditary disease in our region

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This text aims to undertake an analysis of the process of building the "problem of poverty" in Brazil. From a sociological approach on discourses and interpretations of poverty present in literary intellectuals representatives of some of the classics of Brazilian social thought, as well as in scientific works produced from mid-twentieth century and in the reports of various international organizations and national, such as the IMF, World Bank, MDS, IPEA, among others

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The economic regional integration is a phenomenon observed in numerous occasions inside the global economic reality. Watchful to that phenomenon, the 1988 s Brazilian constitutional order establish in its 4th article, single paragraph, the commitment to seek for the Latin- American integration, as a Fundamental Principle to the Brazilian Federative Republic. Regarding the mentioned constitutional disposition s realization, the Brazilian State celebrated, specially, the 1980 s Montevideo Treaty, creating the Latin-American Integration Association, and the 1991 s Asuncion Treaty, performing the duty to establish a common market, in sub regional level, with Argentina, Paraguay and Uruguay, called Mercado Comum do Sul. However, due to an addiction to a wrong comprehension of State s Sovereignty Principle, the Constitution imposes to the international rules an incorporation process, without providing any privilege to those ones regarding the integration constitutional disposition s realization, whether original or derived. The Brazilian s Supreme Court, as matter of fact, affirmed that it is not possible, facing the actual constitutional order, to grant any character of preference. Also in the controversies solution mechanism, responsible for the law s execution in case of its noncompliance, where found malfunctions, most notably the system s open character and its excessive procedural flexibility, in addiction to restricting the access of individuals. It follows from these findings, then, the lack of legal certainty provided by the Mercosul s legal system, considering its effects both international and within the Brazilian state. Among the possible solutions to reduce or eliminate the problem are using the practice of the so-called executive agreements in the Mercosul s original rules incorporation to the Brazilian state, the creation of a Mercosul s court of law and/or a constitutional reform

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This Master s Thesis aims to use the theoretical models of growth with restricted balance of payments, specifically Kaldor (1970) and Thirlwall (1979) models, to analyze the behavior and the pattern of specialization of Brazilian exports and imports in the last years. It is observed that, in some periods, the pattern of specialization has contributed in restricting long-term growth of the Brazilian economy. It has been hypothesized that overall this is due to lack of structural transformation policies. To achieve this goal, it analyzed the performance of Brazilian exports and imports disaggregating them according to their technological content. The basis for comparison was a group of countries to which Brazil is inserted in, the BRIC. In this regard, the work is a comparative analysis by using descriptive statistics. It is concluded that the low rate of GDP growth experienced by Brazil since the 1980s can be explained in part by the decoupling of the Brazilian National Innovation System (NIS) and the Brazilian productive structure. This would be reducing the income elasticity of exports and raising imports, causing a pattern of specialization intensive primary commodities and labor and low-skill labor

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This study aims to investigate the influence of the balance of payments constrained on economic growth in Brazil from 1991 to 2010. With this order, are shown some of the Keynesian balance of payments constrained growth models, inspired by Thirlwall (1979) and Kaldor (1970), which are supported by important points in common, such as adherence to the principle of effective demand. Given that within this theoretical perspective, there is no consensus about the best model to explain the growth rate allowed by the balance of payments constraint, the results are presented by the representative of the empirical literature that addresses the topic, which are necessary for understand the Brazilian case. From the estimation of the income elasticity of imports (0.85) via autoregressive vectors with error correction (VEC), it was calculated five growth rates of income, as predicted by the models of Thirlwall (1979), Thirlwall and Hussain (1982), Moreno-Brid (1998, 2003) and Lourenço et al. (2011) and compared with the actual growth rate. The empirical analysis has shown that: it can not reject the presence of external constraint in the Brazilian economy, there is a strong similarity in growth rates provided by different modeling suggest that growth with external constraint. In addition, when using data in quarterly for the period after 1990 there are no factors that could cause instability in the parameters of the import function (income elasticity and price elasticity of imports) within the period, which indicates that the structural break widely associated with the year 1994 was not confirmed by this study

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Esta tesis de maestría es el resultado de una investigación de carácter cualitativo y etnometodológico, realizada entre agosto de 2003 y junio de 2004, en una escuela primaria estatal, ubicada en Natal RN (Brasil). Su objetivo fue investigar la recepción de la lectura de literatura por parte de una maestra a la que, según reveló, no le gustaba leer y no se consideraba lectora de literatura. Se buscó investigar la mediación que le posibilitara llegar a ser lectora, comprender cuáles son los aspectos que influyen en la relación entre el lector en formación y la lectura de literatura, y verificar cómo repercute ese proceso de formación en la práctica docente de la maestra estudiada. Los procedimientos de investigación fueron aplicados con flexibilidad, tomando en cuenta el proceso de formación lectora de la docente. Los principales instrumentos utilizados fueron dos entrevistas semi-estructuradas, realizadas con la maestra, y notas de campo, que adquirieron el formato de un diario de investigación. En la primera etapa, fueron realizadas treinta sesiones de lectura, para posibilitar el acercamiento de la maestra a diferentes textos literarios. En la segunda etapa, fueron realizados tres encuentros de planificación con la maestra y cinco clases de lectura con sus alumnos. El análisis focaliza la recepción de la lectura literaria por parte de la maestra, abordando diferentes aspectos: su historia en relación con la lectura; la identificación, el contrato ficcional y la relación texto-vida; las previsiones y sus verificaciones; la mediación y el andamiaje brindados para introducir a la maestra en la cultura de la lectura. Se focaliza también la relación entre sus roles de lectora y de mediadora de lectores. Los fundamentos teóricos se basan, principalmente, en Coulon (1995a, 1995b), Vigotsky (1989, 1991, 2003), Graves y Graves (1995), Smith (1991), Jauss (2002), Iser (1996, 1999) y Amarilha (1996, 2001). Como resultados de este trabajo, se destacan el interés de la maestra, la manera en que ella se involucró con las historias leídas mediante procesos de identificación con algunos personajes y la relación que estableció entre los textos y su historia; esos procesos indican avances significativos en su vínculo con la lectura de literatura. La mediación ocupó un papel central en la consecución de aquellos avances. Vale destacar que la relación texto-vida fue establecida por la maestra con cierta ingenuidad, lo que le impidió vivenciar lo ficcional como una actividad lúdica. Se considera necesario un contacto más intenso y regular con textos de ficción, para que la docente pueda distanciarse de su vida cotidiana y adquirir la autonomía y la conciencia transformadora que le permitirán ir y volver de la realidad a la ficción, enriqueciéndose, sin confundirlas. Ese contacto no depende sólo de una actitud individual y personal de la maestra, sino del contexto institucional y social en el cual está inmersa. En ese sentido, la segunda etapa del trabajo de campo demostró que el pasaje de la formación lectora inicial a una acción pedagógica adecuada es complejo; los procesos no son lineales y, todavía, queda un largo camino por recorrer

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Tuberculosis is considered one of the most ancient human diseases, cases were registered 3900 years before Christ, and it is currently regarded as a serious public health problem in the world due to several factors such as income mismanagement, precarious standard of life and some sort of prejudice comprised by the word tuberculosis. Taking this into consideration, it was developed a descriptive and exploratory study aiming at analyzing the social representations of tuberculosis made by its patient from the Unidades de Saúde da Família (Family Health Units a public health program) in Campina Grande City PB, in relation to the decentralization of the policies that administrate the disease. It was interviewed 34 tuberculosis patient that were being treated from 2007 to 2008. The age group of the interviewees varied from 10 to 60 years old, but most of them were between 36 and 60 years old (58,8%, n=20), some were young adult and adult (21 35 years old), with 11 (32,3%) respondents, and, less frequent, children and teenagers (11 20 years old), with 03 (8,8%) participants. Data was collected through semi-structured interview. The questions that guided the research were elaborated based on the operational recommendations of DOTS strategy; that is: access to laboratory examinations; medication guarantee; directly observed treatment. Besides that, the experiences of the patient were considered in their relation with the family and the different social groups. The analysis of the discursive material was submitted to the Analyse Lexicale par Context d un Ensemble de Segments de Texte software - ALCESTE 4.7. Data interpretation showed five categories for the social representations of the tuberculosis patient that participated in DOTS strategy: 1) the accessibility of the health assistance service; 2) the patient perspective of the disease; 3) the change in the operation of the productive life; 4) the signals and symptoms of the tuberculosis disease; 5) the rearrangement and mechanisms used to face the disease. The Central Nucleus reveals that tuberculosis is a transmissible disease that can be prevented by people through educational practices, health promotion, active search for symptomatic respiratory and control of the carriers communication; these mechanisms should be incorporated to the routine of all participants of the family health groups. The Intermediate Elements, based on quotidian life, as well as the individual experiences of the tuberculosis patient, reveals prejudiced attitude and beliefs that lead to isolation and restriction of interpersonal relationship. Peripheral Elements were constituted by themes that showed the patient feelings of indignation because of the social barriers they had to face in the Family Health Units during the treatment. These elements demonstrate a negative perspective of the representation concerning the accessibility, i.e. inadequate structure of the health service; long distance to the Health Centre, this factormakes it difficult for the patient to continue the treatment; scheduling delay; and limited service regarding other requests (doctor, dentist etc). One expects to contribute for the construction of a new perspective of the health question between the different agents who make the assistencial institutions and formation of professionals, either in central or local scope

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Telecommunications play a key role in contemporary society. However, as new technologies are put into the market, it also grows the demanding for new products and services that depend on the offered infrastructure, making the problems of planning telecommunications networks, despite the advances in technology, increasingly larger and complex. However, many of these problems can be formulated as models of combinatorial optimization, and the use of heuristic algorithms can help solving these issues in the planning phase. In this project it was developed two pure metaheuristic implementations Genetic algorithm (GA) and Memetic Algorithm (MA) plus a third hybrid implementation Memetic Algorithm with Vocabulary Building (MA+VB) for a problem in telecommunications that is known in the literature as Problem SONET Ring Assignment Problem or SRAP. The SRAP arises during the planning stage of the physical network and it consists in the selection of connections between a number of locations (customers) in order to meet a series of restrictions on the lowest possible cost. This problem is NP-hard, so efficient exact algorithms (in polynomial complexity ) are not known and may, indeed, even exist

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The SONET/SDH Ring Assignment Problem (PALAS) treats to group localities in form of some rings, being respected the traffic's limitations of the equipment. Each ring uses a DXC (Digital Cross Connect) to make the communication with the others, being the DXC the equipment most expensive of the net, minimizing the number total of rings, will minimize the total net cost, problem's objective . This topology in rings provides a bigger capacity of regeneration. The PALAS is a problem in Combinatorial Optimization of NP-hard Class. It can be solved through Heuristics and Metaheuristics. In this text, we use Taboo Search while we keep a set of elite solutions to be used in the formation of a part of the collection of vocabulary's parts that in turn will be used in the Vocabulary Building. The Vocabulary Building will be started case Taboo Search does not reach the best solution for the instance. Three approaches had been implemented: one that only uses vocabulary's parts deriving of Taboo Search, one that it only uses vocabulary's parts randomly generated and a last one that it uses half come of the elite and half randomly generated

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Particle Swarm Optimization is a metaheuristic that arose in order to simulate the behavior of a number of birds in flight, with its random movement locally, but globally determined. This technique has been widely used to address non-liner continuous problems and yet little explored in discrete problems. This paper presents the operation of this metaheuristic, and propose strategies for implementation of optimization discret problems as form of execution parallel as sequential. The computational experiments were performed to instances of the TSP, selected in the library TSPLIB contenct to 3038 nodes, showing the improvement of performance of parallel methods for their sequential versions, in executation time and results

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The telecommunications play a fundamental role in the contemporary society, having as one of its main roles to give people the possibility to connect them and integrate them into society in which they operate and, therewith, accelerate development through knowledge. But as new technologies are introduced on the market, increases the demand for new products and services that depend on the infrastructure offered, making the problems of planning of telecommunication networks become increasingly large and complex. Many of these problems, however, can be formulated as combinatorial optimization models, and the use of heuristic algorithms can help solve these issues in the planning phase. This paper proposes the development of a Parallel Evolutionary Algorithm to be applied to telecommunications problem known in the literature as SONET Ring Assignment Problem SRAP. This problem is the class NP-hard and arises during the physical planning of a telecommunication network and consists of determining the connections between locations (customers), satisfying a series of constrains of the lowest possible cost. Experimental results illustrate the effectiveness of the Evolutionary Algorithm parallel, over other methods, to obtain solutions that are either optimal or very close to it

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The objective of this study was to investigate the environmental perception of: People with common-sense knowledge on the desertification process in RN. People with scientific knowledge on the desertification process in RN. Focal points in the combat at desertification of the RN and public ministery representant with actions in interinstitutional articulations promoter (and/or relative actions) at the desertification process in the RN. The research was carried in the city of Natal-RN and in two small cities of the Seridó region (RN): Caicó and Currais Novos. The research carried, is classified as exploratory and 22 people were interviewed. The research includes: The propension/intensity of the desertification in the RN and in the Seridó region; Evaluation of the knowledge of those interviewed, concerning the subject desertification ; Problems in order to combat desertification; Causes of desertification; The profile of the interviewed. The results of this present study indicate that the a desertification process is more agressive in the Seridó region than in the state of RN, being the two following: the absence of preocupation of the affected population with the process and the escarcity of governamental recurses, indicates how problems greather in the combat to the phenomen. Decreasing of produtivity in the agriculture and increasing of the migration to the urbans centers have been the main consequences of the process, that have at water scarcity, deforestation and extraction of argil (being this, regional factor), relevant variables in the influence to the surgiment of the desertification process of the RN

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This paper aims to propose a hybrid meta-heuristics for the Heterogeneous Fleet Vehicle Routing Problem (HVRP), which is a combinatorial optimization problem NP-hard, and is characterized by the use of a limited fleet consists of different vehicles with different capacities. The hybrid method developed makes use of a memetic algorithm associated with the component optimizer Vocabulary Building. The resulting hybrid meta-heuristic was implemented in the programming language C + + and computational experiments generated good results in relation to meta-heuristic applied in isolation, proving the efficiency of the proposed method.