Controlador adaptativo por posicionamento de pólos e estrutura variável aplicado ao controle de geradores eólicos baseados em máquina de indução duplamente alimentada

In the last decade, the renewable energy sources have present a major propulsion in the world due to several factors: political, environmental, financial and others. Within this context, we have in particular the energy obtained through wind, wind energy - that has highlighted with rapid growth in recent years, including in Brazil, mostly in the Northeast, due to it s benefit-cost between the clean energies. In this context, we propose to compare the variable structure adaptive pole placement control (VS-APPC) with a traditional control technique proportional integral controller (PI), applied to set the control of machine side in a conversion system using a wind generator based on Double-Fed Induction Generator (DFIG). Robustness and performance tests were carried out to the uncertainties of the internal parameters of the machine and variations of speed reference.

Estudo Comparativo de Métricas de Pontuação para Aprendizagem Estrutural de Redes Bayesianas

Bayesian networks are powerful tools as they represent probability distributions as graphs. They work with uncertainties of real systems. Since last decade there is a special interest in learning network structures from data. However learning the best network structure is a NP-Hard problem, so many heuristics algorithms to generate network structures from data were created. Many of these algorithms use score metrics to generate the network model. This thesis compare three of most used score metrics. The K-2 algorithm and two pattern benchmarks, ASIA and ALARM, were used to carry out the comparison. Results show that score metrics with hyperparameters that strength the tendency to select simpler network structures are better than score metrics with weaker tendency to select simpler network structures for both metrics (Heckerman-Geiger and modified MDL). Heckerman-Geiger Bayesian score metric works better than MDL with large datasets and MDL works better than Heckerman-Geiger with small datasets. The modified MDL gives similar results to Heckerman-Geiger for large datasets and close results to MDL for small datasets with stronger tendency to select simpler network structures

Adaptação eletrônica de um leitor mecânico de coto, investigação e desenvolvimento de interface CAD

Due to advances in the manufacturing process of orthopedic prostheses, the need for better quality shape reading techniques (i.e. with less uncertainty) of the residual limb of amputees became a challenge. To overcome these problems means to be able in obtaining accurate geometry information of the limb and, consequently, better manufacturing processes of both transfemural and transtibial prosthetic sockets. The key point for this task is to customize these readings trying to be as faithful as possible to the real profile of each patient. Within this context, firstly two prototype versions (α and β) of a 3D mechanical scanner for reading residual limbs shape based on reverse engineering techniques were designed. Prototype β is an improved version of prototype α, despite remaining working in analogical mode. Both prototypes are capable of producing a CAD representation of the limb via appropriated graphical sheets and were conceived to work purely by mechanical means. The first results were encouraging as they were able to achieve a great decrease concerning the degree of uncertainty of measurements when compared to traditional methods that are very inaccurate and outdated. For instance, it's not unusual to see these archaic methods in action by making use of ordinary home kind measure-tapes for exploring the limb's shape. Although prototype β improved the readings, it still required someone to input the plotted points (i.e. those marked in disk shape graphical sheets) to an academic CAD software called OrtoCAD. This task is performed by manual typing which is time consuming and carries very limited reliability. Furthermore, the number of coordinates obtained from the purely mechanical system is limited to sub-divisions of the graphical sheet (it records a point every 10 degrees with a resolution of one millimeter). These drawbacks were overcome by designing the second release of prototype β in which it was developed an electronic variation of the reading table components now capable of performing an automatic reading (i.e. no human intervention in digital mode). An interface software (i.e. drive) was built to facilitate data transfer. Much better results were obtained meaning less degree of uncertainty (it records a point every 2 degrees with a resolution of 1/10 mm). Additionally, it was proposed an algorithm to convert the CAD geometry, used by OrtoCAD, to an appropriate format and enabling the use of rapid prototyping equipment aiming future automation of the manufacturing process of prosthetic sockets.

Metodologia de análise e diagnóstico de fratura em um componente automotivo sujeito a cargas cíclicas alternadas

The competitiveness of the trade generated by the higher availability of products with lower quality and cost promoted a new reality of industrial production with small clearances. Track deviations at the production are not discarded, uncertainties can statistically occur. The world consumer and the Brazilian one are supported by the consumer protection code, in lawsuits against the products poor quality. An automobile is composed of various systems and thousands of constituent parts, increasing the likelihood of failure. The dynamic and security systems are critical in relation to the consequences of possible failures. The investigation of the failure gives us the possibility of learning and contributing to various improvements. Our main purpose in this work is to develop a systematic, specific methodology by investigating the root cause of the flaw occurred on an axle end of the front suspension of an automobile, and to perform comparative data analyses between the fractured part and the project information. Our research was based on a flaw generated in an automotive suspension system involved in a mechanical judicial cause, resulting in property and personal damages. In the investigations concerning the analysis of mechanical flaws, knowledge on materials engineering plays a crucial role in the process, since it enables applying techniques for characterizing materials, relating the technical attributes required from a respective part with its structure of manufacturing material, thus providing a greater scientific contribution to the work. The specific methodology developed follows its own flowchart. In the early phase, the data in the records and information on the involved ones were collected. The following laboratory analyses were performed: macrography of the fracture, micrography with SEM (Scanning Electron Microscope) of the initial and final fracture, phase analysis with optical microscopy, Brinell hardness and Vickers microhardness analyses, quantitative and qualitative chemical analysis, by using X-ray fluorescence and optical spectroscopy for carbon analysis, qualitative study on the state of tension was done. Field data were also collected. In the analyses data of the values resulting from the fractured stock parts and the design values were compared. After the investigation, one concluded that: the developed methodology systematized the investigation and enabled crossing data, thus minimizing diagnostic error probability, the morphology of the fracture indicates failure by the fatigue mechanism in a geometrically propitious location, a tension hub, the part was subjected to low tensions by the sectional area of the final fracture, the manufacturing material of the fractured part has low ductility, the component fractured in an earlier moment than the one recommended by the manufacturer, the percentages of C, Si, Mn and Cr of the fractured part present values which differ from the design ones, the hardness value of the superior limit of the fractured part is higher than that of the design, and there is no manufacturing uniformity between stock and fractured part. The work will contribute to optimizing the guidance of the actions in a mechanical engineering judicial expertise

Controle por modos deslizantes com compensação difusa aplicado a sistemas com descontinuidade

The development of non-linear controllers gained space in the theoretical ambit and of practical applications on the moment that the arising of digital computers enabled the implementation of these methodologies. In comparison with the linear controllers more utilized, the non -linear controllers present the advantage of not requiring the linearity of the system to determine the parameters of control, which permits a more efficient control especially when the system presents a high level of non-linearity. Another additional advantage is the reduction of costs, since to obtain the efficient control through linear controllers it is necessary the utilization of sensors and more refined actuators than when it is utilized a non-linear controller. Among the non-linear theories of control, the method of control by gliding ways is detached for being a method that presents more robustness, before uncertainties. It is already confirmed that the adoption of compensation on the region of residual error permits to improve better the performance of these controllers. So, in this work it is described the development of a non-linear controller that looks for an association of strategy of control by gliding ways, with the fuzzy compensation technique. Through the implementation of some strategies of fuzzy compensation, it was searched the one which provided the biggest efficiency before a system with high level of nonlinearities and uncertainties. The electrohydraulic actuator was utilized as an example of research, and the results appoint to two configurations of compensation that permit a bigger reduction of the residual error

Um olhar sobre as veredas rosianas.

The present work objective to study the configurations that the hinterland it acquires in the workmanship Great hinterland: trails, of Guimarães Rosa demonstrating as this author humanize this element, conferring to it characters universal mystics and through investigations, uncertainties, the auto-corrections of Riobaldo that become hinterland a metaphor of the human interior. Three are the chapters, that they will guide this work: the chapter 1 presents as element key for characterization of the epic one in Great hinterland: trails, the mining hinterland replete of trails, palco of exuberant vegetation, huge and multidimensional scene, where it has an entrecruzamento of fiction and reality. It retakes quarrel of critics as Manuel Cavalcanti Proença, Roberto Schwarz, on the existing epic character in the Great hinterland: trails, constructed from deriving myths of the universal culture, that they had been become popular. The brave and gracious knight, that it has its representabilidade in the popular culture. Thus the medieval hero, the knight represented for the Riobaldo personage, it is cognominado by Proença as Don Riobaldo of the Urucuia, knight of the general fields. O chapter 2 is a study on the popular culture in Rosa and Cascudo. Cascudo the example of Rosa also is exímio studious of the brazilian life, the regionalization and the popular manifestations proceeding from other cultures. O chapter 3 it has as focus of analysis two mitopoéticas personages: Diadorim e Luzia-Homem, which in the cited narratives they generally they assume functions generally atribute the men. Since children, if they dresses male. Valley to point out that Diadorim is not characterized as man, since in Great hinterland:trails if trajaq always as gunman. Luzia, when complete 18 anos pass if to dress as woman, but the stigma of male and female, inherited of the time where it coexisted the father folloies it for all the life. They suffer pain to have been born to fight and to não conhecer to love. They die you deliver the God. This study detects exactly that Diadorim and Luzia-Homem, are personages associates the myths of the universal culture and popular (sphinx, Jellyfish, Venus, Mother d water), that they possess similarities n the archetypes, that transit between the sexos masculine and feminine, without any sexual connotation, possesss it proper code of honr, of this not abdicating ahead of the death. Parallel, in this chapter two cascudianas workmanships willbe studies, that contemplate thematic of the dressed woman of man and being the woman without disguice: the enchantment tale Maria Gomes and romance Flower of tragics romances. The first one will be revisited in order to present subject in Great hinterland:trails through the Diadorim personage. As it will discourse on cases of brave women, cited for Cascudo, immortalized for the tradition, who had made history, that already is not disfarçam of men to carry through acts of bravery and honor.

A aula de português no ensino médio: o ensino que se deseja, o ensino que se faz

Settled within the realm of a problematization towards teaching and learning the Portuguese language, this study aims to investigate the way how the Portuguese Language discipline is dealt with in Secondary School. We propose specifically to analyze the orientations of the official documents concerning the educator practice, examining the way the PCNEM proposal is approached in the didactic book, identifying the treatment given to language questions, analyzing the way the teacher uses the didactic book and verifying the relations between the official approach and the pedagogical practice. The analysis takes into account the several discourses concerning school literacy, considering the various political-educational instances which institutionalize the teaching of the mother tongue - where we locate the teaching that is wanted . In what teachers and students say in their activities and concerning them - the realm of the teaching that is performed - we presuppose that there are signs of the principles - or conceptions - that orientate what they understand by language, teaching and learning. Such evidences are considered within the interrelation of the enunciative places where this literacy is promoted: the public policies concerning education - focusing the language questions - the academic researches about those questions, the educator formation and capacitation and the very school practices in the complexity of their discoursive inter-subjectivity. The principles - or conceptions - are pursued in what is said (or not) about what is done (or not) in the classroom when dealing with the Portuguese Language. The corpus is made up of oral and written texts produced in Portuguese classes in the Secondary School at a public school in the city of Natal, Rio Grande do Norte, Brazil. Situated in the realm of Applied Linguistics, the research is conducted in a qualitative and interpretative perspective, following the ethnography of communication procedures and the contributions of the Functional Linguistics. In the observations, language conceptions were discerned, among others, besides beliefs and representations where the theoretical and practical aspects, professional roles, expectations and uncertainties were diluted.

O entardecer de uma era: técnica, poesia e pensamento em Heidegger

The thinking dialog between Heidegger s philosophy and the poetry of Hölderlin and Rilke must be dealt in language s domains. The difficulty to establish this dialog comes from the man in itself, unable to think out of the understructure of science and the modern technique. The poetic language was forgotten or ignored, turning itself obsolete in front of improvements and resources of the technique. Heidegger searches the essences to the poetry so may it be comprehended in its plenitude for the man. Technique, poetry and existence must be pronounced and investigated so the being shows itself again. To Heidegger, the man lives in a period of uncertainty due finding himself at the sunset of age. The uncertainty generates the poverty and the night of world represents the absence of god and original truth. Only with the fundamental comprehension of poetry, the man of today can project himself to the future not anymore as technique product, but with freedom to choose. The message of poetry of Hölderlin and Rilke, according to Heidegger s interpretation, transmits an alert to the contemporary man against the coming danger in his maintained relation with nature. The purpose of the following work is to build this thinking dialog, without disfigure the poetry, but taking approach over its essence, so from there to remove its true existential value.

As provas metafísicas da existência de deus em René Descartes

Le but de cet article est de présenter les éléments de preuve de l existence de Dieu présentée dans les Méditationes Métaphysiques de René Descartes, en soulignant son importance et son rôle dans le projet philosophique cartésien. La recherche visait á comprendre comment Descartes, étant um homme de science, la recherche de Dieu dans le pilier et d assurer leur philosophie. Par consé quence que Descartes propose de remplacer lui promettant de construire une nouvelle science fondée sur des bases sûres. Ainsi, le texte suit um ordre qu une partie de doute méthodologique comme um élément essentiel pour surmonter une connaissance née de l incertitude et généralisée et d opinions comme étant de droite, pour finalement atteindre la vérité dans les sciencies, Grace à la découverte Du premier cours, le cogito, moi pensant, alors existantes. Trouvé cette certitude, le sujet qui a en elle l idée d um être infini qui contient toutes perfections et, comme Il fera la démonstration de la preuve a posteriori et a priori. Et donc cet être ne peut pas être considéré comme inexistant projet assurant Descartes

Análise das curvas de luz do CoroT usando diferentes processos comparativos: estimando períodos de rotação estelar

One of the main goals of CoRoT Natal Team is the determination of rotation period for thousand of stars, a fundamental parameter for the study of stellar evolutionary histories. In order to estimate the rotation period of stars and to understand the associated uncertainties resulting, for example, from discontinuities in the curves and (or) low signal-to-noise ratio, we have compared three different methods for light curves treatment. These methods were applied to many light curves with different characteristics. First, a Visual Analysis was undertaken for each light curve, giving a general perspective on the different phenomena reflected in the curves. The results obtained by this method regarding the rotation period of the star, the presence of spots, or the star nature (binary system or other) were then compared with those obtained by two accurate methods: the CLEANest method, based on the DCDFT (Date Compensated Discrete Fourier Transform), and the Wavelet method, based on the Wavelet Transform. Our results show that all three methods have similar levels of accuracy and can complement each other. Nevertheless, the Wavelet method gives more information about the star, from the wavelet map, showing the variations of frequencies over time in the signal. Finally, we discuss the limitations of these methods, the efficiency to give us informations about the star and the development of tools to integrate different methods into a single analysis

Rotação diferencial em estrelas do tipo solar

Stellar differential rotation is an important key to understand hydromagnetic stellar dynamos, instabilities, and transport processes in stellar interiors as well as for a better treatment of tides in close binary and star-planet systems. The space-borne high-precision photometry with MOST, CoRoT, and Kepler has provided large and homogeneous datasets. This allows, for the first time, the study of differential rotation statistically robust samples covering almost all stages of stellar evolution. In this sense, we introduce a method to measure a lower limit to the amplitude of surface differential rotation from high-precision evenly sampled photometric time series such as those obtained by space-borne telescopes. It is designed for application to main-sequence late-type stars whose optical flux modulation is dominated by starspots. An autocorrelation of the time series is used to select stars that allow an accurate determination of spot rotation periods. A simple two-spot model is applied together with a Bayesian Information Criterion to preliminarily select intervals of the time series showing evidence of differential rotation with starspots of almost constant area. Finally, the significance of the differential rotation detection and a measurement of its amplitude and uncertainty are obtained by an a posteriori Bayesian analysis based on a Monte Carlo Markov Chain (hereafter MCMC) approach. We apply our method to the Sun and eight other stars for which previous spot modelling has been performed to compare our results with previous ones. The selected stars are of spectral type F, G and K. Among the main results of this work, We find that autocorrelation is a simple method for selecting stars with a coherent rotational signal that is a prerequisite to a successful measurement of differential rotation through spot modelling. For a proper MCMC analysis, it is necessary to take into account the strong correlations among different parameters that exists in spot modelling. For the planethosting star Kepler-30, we derive a lower limit to the relative amplitude of the differential rotation. We confirm that the Sun as a star in the optical passband is not suitable for a measurement of the differential rotation owing to the rapid evolution of its photospheric active regions. In general, our method performs well in comparison with more sophisticated procedures used until now in the study of stellar differential rotation

Trajetória de carreira do profissional de recursos humanos

The idea that the career consists in a linear path throughout the individual s professional life structured by the company where he or she works has been changing to a new reality in which the career is seen as a journey, open to possibilities and uncertainties. Several models have come up as an attempt to comprehend and analyze this journey. Among them, there is the model of career narrative, which assumes that, while narrating, individuals give meaning to their own path, and at the same time they consider personal factors and the environment that act on their professional biography. This paper aimed to explore and articulate issues related to the environment and career paths of the human resource professionals working in the Greater Natal. For this purpose, the model of career narrative was used. From the methodological viewpoint, the project was divided in two stages. The first was characterized by conducting a survey with the intention of mapping professionals socio-occupational characteristics, through the application of a semi-structured questionnaire. The data was analyzed by descriptive statistical techniques and cluster analysis. The descriptive statistical analyses included 117 participants. The results indicated that HR professionals of Greater Natal have different functions, develop activities focused on different subsystems, have an increasing career path, and focus their professional formation in Business Administration and Psychology. The second stage of the study was characterized by the use of 17 narrative interviews, whose participants, in the process of nonprobabilistic sampling, were identified based on their belonging to the three clusters: Group 1, HR and public administration; Group 2, HR experts; and Group 3, HR beginners. Analyzing the results of the qualitative phase, it was found that the identification with the activity practiced is a deciding factor for choosing and remaining in the HR field. The lack of professional recognition appears as the main difficulty faced by professionals, as well as the lack of employment opportunity in the Greater Natal. The results analysis leads to a series of discussions on the career path in HR and reflections for this professional category, its representative bodies and educational institutions

Contribuição da teoria do caos para a gestão do turismo: uma análise a partir da percepção dos gestores da hotelaria de Natal/RN

O presente estudo tem como objetivo analisar como os gestores da hotelaria percebem a relação da teoria do caos e turismo, descrever como é pensada e concebida a gestão do turismo; mostrar as características caopléxicas do turismo e sua gestão e identificar os elementos do padrão estratégico de gestão e planejamento na visão dos gestores dos Meios de Hospedagem. Os dados foram obtidos através da observação direta intensiva e aplicação de entrevistas aplicadas junto aos hoteleiros da cidade de Natal/RN. Constata que as teorias da mudança e do caos proporcionam visão do conjunto de relações, aspectos e implicações do turismo, com base nas incertezas e instabilidades ambientais e de mercado. Mostra que a maioria dos modelos de análise, planejamento e gestão do turismo ainda é limitada, em razão do seu caráter linear e unidimensional. Destaca que o objetivo da teoria do caos é fornecer explicações dos fenômenos, não é fazer previsões, pois é impossível prever o futuro a longo prazo. Trata das estratégias de gestão como geradoras de novas fontes de incerteza, pois a realidade não pode ser completamente representada por modelos. Ter consciência desses fatos significa, entretanto, considerar o campo de múltiplas possibilidades e oportunidades da mudança e do caos na gestão do desenvolvimento do turismo. Essas idéias foram aplicadas à análise da gestão do turismo na localidade investigada. Os questionamentos levantados no estudo pautaram-se em pesquisa bibliográfica, fundamentada, principalmente, em autores como Beni, Prahalad, Mintzberg, Ritto, Senge e Hamel. Conclui-se que na era do conhecimento, as organizações que continuam presas ao paradigma mecanicista têm dificuldade de acompanhar as mudanças do mercado e sendo a hotelaria uma indústria de serviços que tem características organizacionais complexas e adaptativas, é imprescindível que os empreendimentos hoteleiros funcionem como sistemas interativos, que acompanhem as mudanças de um mercado tão turbulento e instável tendo na teoria do caos e da complexidade uma das possibilidades de compreender a realidade fora do modelo mecanicista.

Caracterização geométrica e parametrização de depósitos transacionais recentes e sua aplicação na modelagem de reservatórios petrolíferos

In this beginning of the XXI century, the Geology moves for new ways that demand a capacity to work with different information and new tools. It is within this context that the analog characterization has important in the prediction and understanding the lateral changes in the geometry and facies distribution. In the present work was developed a methodology for integration the geological and geophysical data in transitional recent deposits, the modeling of petroliferous reservoirs, the volume calculation and the uncertainties associate with this volume. For this purpose it was carried planialtimetric and geophysics (Ground Penetrating Radar) surveys in three areas of the Parnaíba River. With this information, it was possible to visualize the overlap of different estuary channels and make the delimitation of the channel geometry (width and thickness). For three-dimensional visualization and modeling were used two of the main reservoirs modeling software. These studies were performed with the collected parameters and the data of two reservoirs. The first was created with the Potiguar Basin wells data existents in the literature and corresponding to Açu IV unit. In the second case was used a real database of the Northern Sea. In the procedures of reservoirs modeling different workflows were created and generated five study cases with their volume calculation. Afterwards an analysis was realized to quantify the uncertainties in the geological modeling and their influence in the volume. This analysis was oriented to test the generating see and the analogous data use in the model construction

A fábrica de professores e a padronização do conhecimento

This paper concern the general subject of teacher career construction, since the period of the initial formation in the teaching course of pedagogy crossing the first effectives experiences of professional performance, until the reflections about the results of the continuous formation propositions. The specifics subject is the formative quotidian in the teacher s life beyond of the traditional stereotypes about individuals and institutions bring up for discussion a micro sociological approach about the professionals uncertainty and the personal hopes, the teacher displeasures and the pedagogical satisfactions. The epistemological reflection about the different formatives experiences, taking as example the Programa de Formação de Alfabetizadores PROFA (Alphabetizers Formation Program) developed by the Secretaria Municipal de Educação of Natal City, consider the ambiguous tension between the knowledge that the teachers acquire in their formation and the concrete teachers practical since those experiences. The study methodology is based in the qualitative comprehensive research, sustained by observations, impressive reflective accounts, and also in the theoretic analyses with contemporary references to the critical pedagogical through and education sociology. I used the autobiographic reflective account by the writer-researcher in her owner academic and professional way. I propose an image of a teacher s factory in such a way for its conformist aspects to the continuity stands as much the internal contradictions of the system. Gears, pieces and manual instructions are the educational components of this factory as ideological, institutional and technical structures to aim at to limit the critics and the changes. However the teachers thinking and acting with their owner creativity to adapted uncontexted professional knowledge s to their pedagogical lives. Under those analogies I propose the problem of this research the teacher s formation and theirs pedagogical practices- and also examine briefly its theoretic-philosophical and methodological basis. From the analysis and interpretation of my owner experiential life as teacher s educator I put the necessity of re-thinking the teacher s formation in terms to rebound more meaningfully in their pedagogical actuation. I believe an important part of the teacher s formation process is the personal wish to learn more about the office, explicitly connected to human convictions and values such as to a positive professional identity. Thus, the teacher able to reflect about your owner educator life can find the best way to help the students to think critically about their culture and history, valorizing creative exits by themselves to face the conformist social stands connected with school education