Um sistema para simular o comportamento de bancos trifásicos de reguladores de tensão usados em sistemas de distribuição de energia elétrica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Um estudo do aumento da capacidade de sistemas 3g WCDMA usando técnicas 3.5G de expansão do enlace reverso

The introduction of new digital services in the cellular networks, in transmission rates each time more raised, has stimulated recent research that comes studying ways to increase the data communication capacity and to reduce the delays in forward and reverse links of third generation WCDMA systems. These studies have resulted in new standards, known as 3.5G, published by 3GPP group, for the evolution of the third generation of the cellular systems. In this Masters Thesis the performance of a 3G WCDMA system, with diverse base stations and thousand of users is developed with assists of the planning tool NPSW. Moreover the performance of the 3.5G techniques hybrid automatic retransmission and multi-user detection with interference cancellation, candidates for enhance the WCDMA uplink capacity, is verified by means of computational simulations in Matlab of the increase of the data communication capacity and the reduction of the delays in the retransmission of packages of information

Estudos e projetos de filtro interdigital em microfita para aplicação prática ao transponder do satélite ITASAT

This work shows a theoretical analysis together with numerical and experimental results of transmission characteristics from the microstrip bandpass filters with different geometries. These filters are built over isotropic dielectric substrates. The numerical analysis is made by specifical commercial softwares, like Ansoft Designer and Agilent Advanced Design System (ADS). In addition to these tools, a Matlab Script was built to analyze the filters through the Finite-Difference Time-Domain (FDTD) method. The filters project focused the development of the first stage of filtering in the ITASAT s Transponder receptor, and its integration with the others systems. Some microstrip filters architectures have been studied, aiming the viability of implementation and suitable practical application for the purposes of the ITASAT Project due to its lowspace occupation in the lower UHF frequencies. The ITASAT project is a Universityexperimental project which will build a satellite to integrate the Brazilian Data Collect System s satellite constellation, with efforts of many Brazilian institutes, like for example AEB (Brazilian Spatial Agency), ITA (Technological Institute of Aeronautics), INPE/CRN (National Institute of Spatial Researches/Northeastern Regional Center) and UFRN (Federal University of Rio Grande do Norte). Comparisons were made between numerical and experimental results of all filters, where good agreements could be noticed, reaching the most of the objectives. Also, post-work improvements were suggested.

ISE-SPL: Uma abordagem baseada em linha de produtos de software aplicada à geração automática de sistemas para educação médica na plataforma E-learning

E-learning, which refers to the use of Internet-related technologies to improve knowledge and learning, has emerged as a complementary form of education, bringing advantages such as increased accessibility to information, personalized learning, democratization of education and ease of update, distribution and standardization of the content. In this sense, this paper aims to develop a tool, named ISE-SPL, whose purpose is the automatic generation of E-learning systems for medical education, making use of concepts of Software Product Lines. It consists of an innovative methodology for medical education that aims to assist professors of healthcare in their teaching through the use of educational technologies, all based on computing applied to healthcare (Informatics in Health). The tests performed to validate the ISE-SPL were divided into two stages: the first was made by using a software analysis tool similar to ISE-SPL, called SPLOT and the second was performed through usability questionnaires to healthcare professors who used ISESPL. Both tests showed positive results, proving it to be an efficient tool for generation of E-learning software and useful for professors in healthcare

Uma proposta de metodologia para o ensino de Física usando robótica de baixíssimo custo

This paper presents methodology based on Lev Vigotsky`s social interactionist theory through investigative activities, which integrates the teaching of physics to robotics, directed to students of the Physics degree course, seeking to provide further training for future teachers. The method is organized through educational robotics workshops that addresses concepts of physics through the use of low-cost educational robots along with several activities. The methodology has been presented and discussed and put into practice afterwards in workshops so that these future teachers may be able to take robotics to their classroom. Students from the last and penultimate semester of the Physics degree course of the Federal Institute of Education, Science and Technology of Rio Grande do Norte, Caicó campus participated in this project

Utilização da lógica difusa no controle inteligente de sistemas eletro-hidráulicos

Electro-hydraulic servo-systems are widely employed in industrial applications such as robotic manipulators, active suspensions, precision machine tools and aerospace systems. They provide many advantages over electric motors, including high force to weight ratio, fast response time and compact size. However, precise control of electro-hydraulic systems, due to their inherent nonlinear characteristics, cannot be easily obtained with conventional linear controllers. Most flow control valves can also exhibit some hard nonlinearities such as deadzone due to valve spool overlap on the passage´s orifice of the fluid. This work describes the development of a nonlinear controller based on the feedback linearization method and including a fuzzy compensation scheme for an electro-hydraulic actuated system with unknown dead-band. Numerical results are presented in order to demonstrate the control system performance

Controle inteligente de sistemas eletroidráulicos utilizando redes neurais artificiais

This work describes the development of a nonlinear control strategy for an electro-hydraulic actuated system. The system to be controlled is represented by a third order ordinary differential equation subject to a dead-zone input. The control strategy is based on a nonlinear control scheme, combined with an artificial intelligence algorithm, namely, the method of feedback linearization and an artificial neural network. It is shown that, when such a hard nonlinearity and modeling inaccuracies are considered, the nonlinear technique alone is not enough to ensure a good performance of the controller. Therefore, a compensation strategy based on artificial neural networks, which have been notoriously used in systems that require the simulation of the process of human inference, is used. The multilayer perceptron network and the radial basis functions network as well are adopted and mathematically implemented within the control law. On this basis, the compensation ability considering both networks is compared. Furthermore, the application of new intelligent control strategies for nonlinear and uncertain mechanical systems are proposed, showing that the combination of a nonlinear control methodology and artificial neural networks improves the overall control system performance. Numerical results are presented to demonstrate the efficacy of the proposed control system

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

Determinação de dados de equilíbrio de fases para sistemas aquosos com eletrólitos

In the present work are established initially the fundamental relationships of thermodynamics that govern the equilibrium between phases, the models used for the description of the behavior non ideal of the liquid and vapor phases in conditions of low pressures. This work seeks the determination of vapor-liquid equilibrium (VLE) data for a series of multicomponents mixtures of saturated aliphatic hydrocarbons, prepared synthetically starting from substances with analytical degree and the development of a new dynamic cell with circulation of the vapor phase. The apparatus and experimental procedures developed are described and applied for the determination of VLE data. VLE isobarics data were obtained through a Fischer s ebulliometer of circulation of both phases, for the systems pentane + dodecane, heptane + dodecane and decane + dodecane. Using the two new dynamic cells especially projected, of easy operation and low cost, with circulation of the vapor phase, data for the systems heptane + decane + dodecane, acetone + water, tween 20 + dodecane, phenol + water and distillation curves of a gasoline without addictive were measured. Compositions of the equilibrium phases were found by densimetry, chromatography, and total organic carbon analyzer. Calibration curves of density versus composition were prepared from synthetic mixtures and the behavior excess volumes were evaluated. The VLE data obtained experimentally for the hydrocarbon and aqueous systems were submitted to the test of thermodynamic consistency, as well as the obtained from the literature data for another binary systems, mainly in the bank DDB (Dortmund Data Bank), where the Gibbs-Duhem equation is used obtaining a satisfactory data base. The results of the thermodynamic consistency tests for the binary and ternary systems were evaluated in terms of deviations for applications such as model development. Later, those groups of data (tested and approved) were used in the KijPoly program for the determination of the binary kij parameters of the cubic equations of state original Peng-Robinson and with the expanded alpha function. These obtained parameters can be applied for simulation of the reservoirs petroleum conditions and of the several distillation processes found in the petrochemistry industry, through simulators. The two designed dynamic cells used equipments of national technology for the determination of VLE data were well succeed, demonstrating efficiency and low cost. Multicomponents systems, mixtures of components of different molecular weights and also diluted solutions may be studied in these developed VLE cells

Determinação de Dados de Equilíbrio Líquido-Vapor para Sistemas Hidrocarbonetos e Desenvolvimento de uma Nova Célula Dinâmica

In the present work are established initially the fundamental relationships of thermodynamics that govern the equilibrium between phases, the models used for the description of the behavior non ideal of the liquid and vapor phases in conditions of low pressures. This work seeks the determination of vapor-liquid equilibrium (VLE) data for a series of multicomponents mixtures of saturated aliphatic hydrocarbons, prepared synthetically starting from substances with analytical degree and the development of a new dynamic cell with circulation of the vapor phase. The apparatus and experimental procedures developed are described and applied for the determination of VLE data. VLE isobarics data were obtained through a Fischer's ebulliometer of circulation of both phases, for the systems pentane + dodecane, heptane + dodecane and decane + dodecane. Using the two new dynamic cells especially projected, of easy operation and low cost, with circulation of the vapor phase, data for the systems heptane + decane + dodecane, acetone + water, tween 20 + dodecane, phenol + water and distillation curves of a gasoline without addictive were measured. Compositions of the equilibrium phases were found by densimetry, chromatography, and total organic carbon analyzer. Calibration curves of density versus composition were prepared from synthetic mixtures and the behavior excess volumes were evaluated. The VLE data obtained experimentally for the hydrocarbon and aqueous systems were submitted to the test of thermodynamic consistency, as well as the obtained from the literature data for another binary systems, mainly in the bank DDB (Dortmund Data Bank), where the Gibbs-Duhem equation is used obtaining a satisfactory data base. The results of the thermodynamic consistency tests for the binary and ternary systems were evaluated in terms of deviations for applications such as model development. Later, those groups of data (tested and approved) were used in the KijPoly program for the determination of the binary kij parameters of the cubic equations of state original Peng-Robinson and with the expanded alpha function. These obtained parameters can be applied for simulation of the reservoirs petroleum conditions and of the several distillation processes found in the petrochemistry industry, through simulators. The two designed dynamic cells used equipments of national technology for the determination Humberto Neves Maia de Oliveira Tese de Doutorado PPGEQ/PRH-ANP 14/UFRN of VLE data were well succeed, demonstrating efficiency and low cost. Multicomponents systems, mixtures of components of different molecular weights and also diluted solutions may be studied in these developed VLE cells

Avaliação da eficiência da remoção de matéria orgânica e microbiológica de três sistemas de lagoas de estabilização em série na Grande Natal-RN: Beira Rio, Jardim Lola I e Jardim Lola II

Waste stabilization ponds are the main technology in use for domestic sewage treatment in Rio Grande do Norte State (RN), northeast Brazil. The are around 80 systems, constructed mainly by municipal city halls, being series comprised by a primary facultative pond followed by two maturation ponds the most used configuration. Due to problems related with the production and destination of sludge and generation of bad odors, the designers have avoided the use of anaerobic lagoons. The majority of systems are rarely monitored to verify their efficiencies and to get new project parameters for future designing. This work has as purpose to make a diagnosis of efficiency of three series of waste stabilization pond series (WSPS) of Jardim Lola 1, Jardim Lola 2 and Beira Rio, located in the North Zone of the city of the Natal/RN, treating domestic raw sewage, on the removal of organic matter and thermotolerant coliform, comparing the operational conditions of the systems this inside of the bands foreseen in the project, through parameters BOD5, QOD, thermotolerant coliforms, dissolved oxygen, pH, temperature, ammoniac nitrogen, total and suspended solids. The work was carried through in the WSPS, all constituted by a primary facultative pond followed by two maturation ponds. Socioeconomic characteristics of population are predominantly low and all the plants are very near of the contributing basins. The series were monitored from of May the November of 2002, totalizing 20 collections of grab samples of raw sewage and ponds effluents between 8:00 and 9:50 h. The main aspect to be detached by the results was the great concentration of organic matter (BOD and COD) and microorganisms the raw sewage which were around two times more concentrated than those values foreseen one in project. Considering all series the highest removals of organic matter were observed in system Beira Rio (84 and 78% of BOD and COD, respectively), which presented high hydraulic detention time (TDH = 89 days). On the other hand, Jardim Lola 1 and Jardim Lola 2 presented a much lower values of HDT (36 days and 18 days respectively) and their removals of BOD and COD were the same (76% and 60%, respectively). The Beira Rio WSPS, was the most efficient verified in relation to solids and ammonia, proving the great influence of the operational variables such as HDT and applied surface organic loadings on the performance of pond series. Although the treatment plants have reached efficiencies of thermotolerant coliforms around 99,999%, the concentrations in the final effluent can be considered very high for launching in aquatic bodies, particularly those produced by Jardim Lola 1 and Jardim Lola 2 series

O espaço formativo na escola: um estudo com professoras dos 4º e 5º anos do ensino fundamental.

Es extensa, de parte de los docentes, la discusión sobre la articulación de actividades y estrategias de enseñanza que vengan a proporcionar una participación más activa del alumnado. Sin embargo tal tarea constituye un desafío para muchos profesores ya que, muchas veces, la formación inicial no siempre los prepara para esta perspectiva. Nosotros entendemos que es necesario desarrollar en los maestros una autonomía crítica, tomando la escuela como espacio formativo. El objetivo de este trabajo fue él de incentivar un espacio de discusión y reflexión para profesores en ejercicio de los 4° y 5° años de la Enseñanza Fundamental I. Ese espacio que era orientado para que ellos estudiasen y articulasen, entre otras cosas, el conocimiento disciplinar de Ciencias y la organización y sistematización de actividades de enseñanza que lleven a una participación más activa de los estudiantes. La investigación se realizó en una escuela privada de Natal/RN, que atiende a estudiantes desde la educación infantil hasta la enseñanza secundaria. Se desarrolló en cuatro fases: la 1ª, de familiarización, cuyo objeto de estudio se dio a través de la observación del salón de clase y del análisis de la planificación anual: la 2ª, de identificación de las dificultades de los maestros, teniendo como instrumentos encuestas con preguntas abiertas y elaboración de textos. La 3ª, en la perspectiva de proporcionar una intervención, se usó como instrumentos de investigación, el diario de clase y otras actividades como talleres, cursos y la elaboración de material didáctico. En la 4ª fase, para reconocer los posibles cambios en la práctica docente, ocurrieron nuevas observaciones en el salón de clase, el análisis de las planificaciones. Los datos obtenidos fueron organizados en tablas y clasificados. Los resultados señalan cambios en la práctica de esos profesionales, la introducción de la disciplina de Ciencias en el espacio formativo y el material didáctico elaborado ha sido un subsidio importante para ayudarlos en las clases

Propriedades dos sistemas de numeração: uma sequência didática em uma abordagem histórica

This paper aims to describe the construction and validation of a notebook of activities whose content is a didactic sequence that makes use of the study of ancient numbering systems as compared to the object of our decimal positional numbering system Arabic. This is on the assumption that the comparison with a system different from our own might provide a better understanding of our own numbering system, but also help in the process of arithmetic operations of addition, subtraction and multiplication, since it will force us to think in ways that are not routinely object of our attention. The systems covered in the study were the Egyptian hieroglyphic system of numbering, the numbering system Greek alphabet and Roman numbering system, always compared to our numbering system. The following teachung is presented structured in the form of our activities, so-called exercise set and common tasks around a former same numbering system. In its final stage of preparation, the sequence with the participation of 26 primary school teachers of basic education

Crenças de professores do município de Caicó RN sobre o ensino de gramática nos anos iniciais do nível fundamental

Este trabalho tem como objetivo analisar as crenças de professores das séries iniciais do nível fundamental da cidade de Caicó-RN sobre o ensino de gramática. A partir da aplicação de um questionário, analisam-se as crenças manifestadas no discurso de 20 docentes da rede municipal de ensino do referido município. As questões formuladas visaram investigar as crenças dos informantes sobre o que é ensinar gramática e que dificuldades encontram para realizar o ensino dos conteúdos gramaticais, considerando aspectos teóricos e práticos, entre eles: a construção da concepção sobre ensino de gramática, a participação em projetos de formação continuada na especificidade de ensino de língua, a influência dessa formação sobre o seu fazer pedagógico, e a realização do planejamento de ensino de conteúdos gramaticais. Para fundamentar a reflexão, buscou-se apoio em autores como Abrahão; Barcelos (2006); Antunes (2009; 2007); Neves (2004a; 2004b; 2007; 2010) Silva (2004; 2007), Travaglia (2001; 2004); entre outros, a partir dos quais são abordados os conceitos de língua, linguagem e gramática, relacionando-os ao desenvolvimento da competência linguística/comunicativa no ensino de língua portuguesa. Os dados analisados revelam que a influência das crenças sobre o ensino de gramática no fazer pedagógico do professor se relaciona com sua formação acadêmica, desde a escolha do referencial teórico adotado pelos professores das disciplinas relacionadas ao tema até a metodologia utilizada para trabalhar os conteúdos, considerando as experiências pessoais concretizadas ao longo de sua vida. Além disso, percebeu-se que existe uma forte convergência entre crenças, conhecimentos e experiências práticas. O trabalho conclui-se com uma reflexão sobre as implicações que uma postura reflexiva pode ter no atual panorama de ensino de língua, em geral, e de gramática, em particular.

As práticas exitosas de leitura no ensino fundamental: vozes sociais de professores e de estudantes

The school is the social place which should provide the formation of critical readers. In this context, the role of the teacher is crucial when it comes to teaching reading. Thus, this doctoral research aims to explicit the reading practices evidenced from social voices of teachers and Fundamental School students from state public schools at RN that have successful results, according to IDEB 2009. Moreover, we seek to explicit, through the positions of teachers, the conceptions of reading underlying their reading activities, as well as elucidate the social voices related to teaching of reading that are present in the National Curriculum Guide for 9 years Fundamental School and in the Political-Pedagogical Projects of the educational institutions investigated. In order to accomplish this goal, we carried out observations in the classroom, applied questionnaires with teachers and students in the 9th grade of Fundamental School, in classes of Portuguese Language, and also performed dialogical meetings with the management and pedagogics schools teams. The theoretical foundation that guides the research comes from bakhtinian thinking (2009, 2010), which addresses the dialogical perspective of language and active responsive comprehension. Furthermore, this work is anchored in theoretical reflections of Antunes (2005, 2009) and Geraldi (2003, 2006, 2010) about the reading and writing in the country, which contribute to the resizing of the teaching and learning process of Portuguese Language. This study belongs to the field of Applied Linguistics, which investigates language as social practice in the context of learning mother language or in contexts where relevant questions about the use of language are evidenced. The parameters of qualitative research in a social-historic perspective are adopted seeking to understand the school context by the subjects involved in research. The research corpus is composed of: (i) information constructed through the use of questionnaires with teachers and students; (ii) information constructed from the observed lesson and dialogue with management and pedagogical teams; (iii) a set of selected information, i.e., empiricism built through documentary analysis of the National Curriculum Guide for 9 years Fundamental School (CONSELHO NACIONAL DE EDUCAÇÃO, 2010) and the Political- Pedagogical Projects of the investigated schools. The analysis of the sayings of teachers and students suggest reading practices from various texts, in particular, from the literary sphere, in activities involving discussions, reading and reading comprehension exercises, interviews, songs, seminars organizations, concerts, dramatizations, literary weeks, among other practices. Furthermore, these analyses reveal that teach Portuguese Language requires commitment, responsibility and satisfaction, as well as more grounded theoretical principles, which make teaching practice more efficient. The research also reveals that the success of the teaching-learning process occurs by virtue of the involvement of school s segments in the educational process, creating therefore a network of responsibilities. In this sense, this research may contribute to the production of knowledge that can guide and enrich the teaching and learning of reading, envisioning a pedagogical practice constructed from the relationship with the other, i.e., from the dialogism which provides formation of young people that exercise their citizenship