Contribuições à estratégia de controle sem detecção de harmônicos aplicada a um filtro ativo de potência paralelo

The conventional control schemes applied to Shunt Active Power Filters (SAPF) are Harmonic extractor-based strategies (HEBSs) because their effectiveness depends on how quickly and accurately the harmonic components of the nonlinear loads are identified. The SAPF can be also implemented without the use of the load harmonic extractors. In this case, the harmonic compensating term is obtained from the system active power balance. These systems can be considered as balanced-energy-based schemes (BEBSs) and their performance depends on how fast the system reaches the equilibrium state. In this case, the phase currents of the power grid are indirectly regulated by double sequence controllers with two degrees of freedom, where the internal model principle is employed to avoid reference frame transformation. Additionally the DSC controller presents robustness when the SAPF is operating under unbalanced conditions. Furthermore, SAPF implemented without harmonic detection schemes compensate simultaneously harmonic distortion and reactive power of the load. Their compensation capabilities, however, are limited by the SAPF power converter rating. Such a restriction can be minimized if the level of the reactive power correction is managed. In this work an estimation scheme for determining the filter currents is introduced to manage the compensation of reactive power. Experimental results are shown for demonstrating the performance of the proposed SAPF system.

Contribuições para o estudo do código neural

Os recentes avanços técnicos das duas últimas décadas para o registro de sinais neuroeletrofisiológicos foram essenciais para que se testassem hipóteses há muito propostas acerca de como células nervosas processam e armazenam informação. No entanto, ao permitir maior detalhamento dos dados coletados, as novas tecnologias levam inevitavelmente ao aumento de sua complexidade estatística e, consequentemente, à necessidade de novas ferramentas matemático-computacionais para sua análise. Nesta tese, apresentamos novos métodos para a análise de dois componentes fundamentais nas atuais teorias da codificação neural: (1) assembleias celulares, definidas pela co-ativação de subgrupos neuronais; e (2) o padrão temporal de atividade de neurônios individuais. Em relação a (1), desenvolvemos um método baseado em análise de componentes independentes para identificar e rastrear padrões de co-ativação significativos com alta resolução temporal. Superamos limitações de métodos anteriores, ao efetivamente isolar assembleias e abrir a possibilidade de analisar simultaneamente grandes populações neuronais. Em relação a (2), apresentamos uma nova técnica para a extração de padrões de atividade em trens de disparo baseada na decomposição wavelet. Demonstramos, por meio de simulações e de aplicação a dados reais, que nossa ferramenta supera as mais utilizadas atualmente para decodificar respostas de neurônios e estimar a informação de Shannon entre trens de disparos e estímulos externos.

For the win (FTW)! Contribuições de um serious game para o ensino-aprendizagem de argumentação

This is a qualitative and reflexive research with focus on digital literacy. Among the digital media that could support the teaching of argumentation in the Science & Technology and Information Technology undergraduate courses of the Federal University of Rio Grande do Norte, we chose a serious game as object of research. Given the object of study in the discipline of reading and writing II – argumentation and genre from the order of argumentative writing -, common to the undergraduate courses mentioned, we invest on the development of a serious game, named ArgumentACTION, because we believe that it may, in fact, become a promising didactic instrument. Therefore we intend to understand whether and how this game can help students develop their reading and writing skills more independently, specifically towards an argumentative order genre: the opinion piece. With this research, we intend to contribute to the teaching of the Portuguese language on three bases: extending theoretical scope, in order to generate greater intelligibility on the teaching-learning process of argumenting; proposing a new methodological possibility, with the incorporation of a serious games to teaching; perfecting the game with which we are working, in order to build – and make available – a more refined digital tool to subsidize the teaching and learning of reading and writing of opinion pieces. To do so, we use the following as theoretical-methodological: Studies of Literacy (KLEIMAN, 2012b; TINOCO, 2008; OLIVEIRA, 2010; GEE, 2009; 2010; ROJO, 2012), The Applied Linguistics (KLEIMAN, 1998; BUSH-LEE, 2009), The Philosophy of Language (BAKHTIN, VOLOSHINOV, 2012) and Critical Pedagogy (DEWEY, 2010). A group of students from the upper mentioned undergraduate courses collaborated with this research by playing and analyzing the game. They were also interviewed about their experience in this matter. From the data generated, we established the categories of analysis: decollection, interest, multimodality/multisemiosis and interactivity, agent of literacy, learning principles. The conclusions we obtained show that the investment in applications, especially games, can bring real benefits to the teaching/learning of the Portuguese language; moreover they reveal that the work on argumenting has much to gain with the incorporation of serious games; however the possible advantages depend on a focused teaching practice and constant improvements and updates of this type of interactive tool, as well as the pedagogical practice from those who use and develop the games.

Contribuições para o processo de verificação de satisfatibilidade módulo teoria em Event-B

Event-B is a formal method for modeling and verification of discrete transition systems. Event-B development yields proof obligations that must be verified (i.e. proved valid) in order to keep the produced models consistent. Satisfiability Modulo Theory solvers are automated theorem provers used to verify the satisfiability of logic formulas considering a background theory (or combination of theories). SMT solvers not only handle large firstorder formulas, but can also generate models and proofs, as well as identify unsatisfiable subsets of hypotheses (unsat-cores). Tool support for Event-B is provided by the Rodin platform: an extensible Eclipse based IDE that combines modeling and proving features. A SMT plug-in for Rodin has been developed intending to integrate alternative, efficient verification techniques to the platform. We implemented a series of complements to the SMT solver plug-in for Rodin, namely improvements to the user interface for when proof obligations are reported as invalid by the plug-in. Additionally, we modified some of the plug-in features, such as support for proof generation and unsat-core extraction, to comply with the SMT-LIB standard for SMT solvers. We undertook tests using applicable proof obligations to demonstrate the new features. The contributions described can potentially affect productivity in a positive manner.

Contribuições para estratégia de controle aplicada à geração fotovoltaica interconectada à rede elétrica

Generation systems, using renewable sources, are becoming increasingly popular due to the need for increased use of electricity. Currently, renewables sources have a role to cooperate with conventional generation, due to the system limitation in delivering the required power, the need for reduction of unwanted effects from sources that use fossil fuels (pollution) and the difficulty of building new transmission and/or distribution lines. This cooperation takes place through distributed generation. Therefore, this work proposes a control strategy for the interconnection of a PV (Photovoltaic) system generation distributed with a three-phase power grid through a connection filter the type LCL. The compensation of power quality at point of common coupling (PCC) is performed ensuring that the mains supply or consume only active power and that his currents have low distorcion. Unlike traditional techniques which require schemes for harmonic detection, the technique performs the harmonic compensation without the use of this schemes, controlling the output currents of the system in an indirect way. So that there is effective control of the DC (Direct Current) bus voltage is used the robust controller mode dual DSMPI (Dual-Sliding Mode-Proportional Integral), that behaves as a sliding mode controller SM-PI (Sliding Mode-Proportional Integral) during the transition and like a conventional PI (Proportional Integral) in the steady-state. For control of current is used to repetitive control strategy, which are used double sequence controllers (DSC) tuned to the fundamental component, the fifth and seventh harmonic. The output phase current are aligned with the phase angle of the utility voltage vector obtained from the use of a SRF-PLL (Synchronous Reference Frame Phase-Locked-Loop). In order to obtain the maximum power from the PV array is used a MPPT (Maximum Power Point Tracking) algorithm without the need for adding sensors. Experimental results are presented to demonstrate the effectiveness of the proposed control system.

Contribuições em escalonamento e análise de desempenho de redes WirelessHART

Wireless Communication is a trend in the industrial environment nowadays and on this trend, we can highlight the WirelessHART technology. In this situation, it is natural the search for new improvements in the technology and such improvements can be related directly to the routing and scheduling algorithms. In the present thesis, we present a literature review about the main specific solutions for Routing and scheduling for WirelessHART. The thesis also proposes a new scheduling algorithm called Flow Scheduling that intends to improve superframe utilization and flexibility aspects. For validation purposes, we develop a simulation module for the Network Simulator 3 (NS-3) that models aspects like positioning, signal attenuation and energy consumption and provides an link individual error configuration. The module also allows the creation of the scheduling superframe using the Flow and Han Algorithms. In order to validate the new algorithms, we execute a series of comparative tests and evaluate the algorithms performance for link allocation, delay and superframe occupation. In order to validate the physical layer of the simulation module, we statically configure the routing and scheduling aspects and perform reliability and energy consumption tests using various literature topologies and error probabilities.

Contribuições em escalonamento e análise de desempenho de redes WirelessHART

Wireless Communication is a trend in the industrial environment nowadays and on this trend, we can highlight the WirelessHART technology. In this situation, it is natural the search for new improvements in the technology and such improvements can be related directly to the routing and scheduling algorithms. In the present thesis, we present a literature review about the main specific solutions for Routing and scheduling for WirelessHART. The thesis also proposes a new scheduling algorithm called Flow Scheduling that intends to improve superframe utilization and flexibility aspects. For validation purposes, we develop a simulation module for the Network Simulator 3 (NS-3) that models aspects like positioning, signal attenuation and energy consumption and provides an link individual error configuration. The module also allows the creation of the scheduling superframe using the Flow and Han Algorithms. In order to validate the new algorithms, we execute a series of comparative tests and evaluate the algorithms performance for link allocation, delay and superframe occupation. In order to validate the physical layer of the simulation module, we statically configure the routing and scheduling aspects and perform reliability and energy consumption tests using various literature topologies and error probabilities.

A responsabilidade enunciativa em artigos científicos de pesquisadores iniciantes e contribuições para o ensino da produção textual na graduação

This thesis investigates materialization strategies of non-assumption of enunciation responsibility and inscription of an authorial voice in scientific articles produced by initial researchers in Linguistics. The specific focus lays on identify, describe and interpret: i) linguistics marks that assign enunciation responsibility; ii) the positions taken by the first speaker-enunciator (L1/E1) in relation to points of view (PoV) imputed to second enunciators (e2); and iii) the linguistic marks that assign the formulation of themselves' PoV. As a practical deployment, it is proposed to discuss how to teach taking into account text discursive strategies regarding to enunciation responsibility and also authorship in academic and scientific texts. Our research corpus is formed by eight scientific essays and they were selected in a renamed Linguistics scientific magazine which is high evaluated by Qualis/CAPES (Brazil Science Agency). The methodology follows the assumptions of a qualitative research, and an it has such an interpretative basis, even though it takes support in a quantitative approach, too. Theoretically, we based this research on Textual Analysis of Speech and linguistics theories about linguistic enunciation area. The results show two kinds of movements in PoV management: imputation and responsibility. In imputation contexts, the most recursive linguistic marks were reported speech, indirect speech, reported speech with “that”, modalization in reported speech (in enunciation with “according to”, “in agreement with”, “for”), beyond that we see certain points of non-coincidences of speech, specifically the non-coincidence of the speech itself. The way those linguistic marks occur in the text point out three kinds of enunciation positions that are assumed by L1/E1 in relation to PoV of e2: agreement, disagreement and a pseudo neutrality. It was clearly recursive the imputation followed by agreement (explicit or not), this perspective puts other’s voices to defend a speech assumed like own authorship. In speech responsibility contexts, we observed such a formulation of inner PoV that results from theoretical findings undertaken by novice researchers (revealing how he/she interpreted concepts of the theory) or arising from their research data, allowing them to express with more autonomy and without reporting to speeches from e2. Based on those data, we can say that, in text by initial researchers, the authorship is strongly built upon PoV and also dependent from others' words (theory and the scholars quoted there), taking into account that many contexts in which we can observe agreement position, PoV formulations with words taken from e2 and assumed as own words by syntactic integration, the comments about what the other says, the absence of explanations and additions, as well as a data analysis that could show agreement with the theory used to support the work. These results allow us to visualize how initial researcher dialogs with the theoretical enunciation sources he or she takes as support and how he/she displays the status of a subject doing a research and positioning himself/herself as a researcher/author in the scientific field. In assuming the reported speech, when quoting, as a resource that allows the enunciation responsibility and also when doing evidence to the positions of speaker-enunciator in relation do reported PoV, this suggests to a textual-discursive treatment of quoting in academic and scientific text, in a context of teaching that gives attention to the development of communication skills of initial researcher and that can contribute to insert and interact students in the scientific field.

A responsabilidade enunciativa em artigos científicos de pesquisadores iniciantes e contribuições para o ensino da produção textual na graduação

This thesis investigates materialization strategies of non-assumption of enunciation responsibility and inscription of an authorial voice in scientific articles produced by initial researchers in Linguistics. The specific focus lays on identify, describe and interpret: i) linguistics marks that assign enunciation responsibility; ii) the positions taken by the first speaker-enunciator (L1/E1) in relation to points of view (PoV) imputed to second enunciators (e2); and iii) the linguistic marks that assign the formulation of themselves' PoV. As a practical deployment, it is proposed to discuss how to teach taking into account text discursive strategies regarding to enunciation responsibility and also authorship in academic and scientific texts. Our research corpus is formed by eight scientific essays and they were selected in a renamed Linguistics scientific magazine which is high evaluated by Qualis/CAPES (Brazil Science Agency). The methodology follows the assumptions of a qualitative research, and an it has such an interpretative basis, even though it takes support in a quantitative approach, too. Theoretically, we based this research on Textual Analysis of Speech and linguistics theories about linguistic enunciation area. The results show two kinds of movements in PoV management: imputation and responsibility. In imputation contexts, the most recursive linguistic marks were reported speech, indirect speech, reported speech with “that”, modalization in reported speech (in enunciation with “according to”, “in agreement with”, “for”), beyond that we see certain points of non-coincidences of speech, specifically the non-coincidence of the speech itself. The way those linguistic marks occur in the text point out three kinds of enunciation positions that are assumed by L1/E1 in relation to PoV of e2: agreement, disagreement and a pseudo neutrality. It was clearly recursive the imputation followed by agreement (explicit or not), this perspective puts other’s voices to defend a speech assumed like own authorship. In speech responsibility contexts, we observed such a formulation of inner PoV that results from theoretical findings undertaken by novice researchers (revealing how he/she interpreted concepts of the theory) or arising from their research data, allowing them to express with more autonomy and without reporting to speeches from e2. Based on those data, we can say that, in text by initial researchers, the authorship is strongly built upon PoV and also dependent from others' words (theory and the scholars quoted there), taking into account that many contexts in which we can observe agreement position, PoV formulations with words taken from e2 and assumed as own words by syntactic integration, the comments about what the other says, the absence of explanations and additions, as well as a data analysis that could show agreement with the theory used to support the work. These results allow us to visualize how initial researcher dialogs with the theoretical enunciation sources he or she takes as support and how he/she displays the status of a subject doing a research and positioning himself/herself as a researcher/author in the scientific field. In assuming the reported speech, when quoting, as a resource that allows the enunciation responsibility and also when doing evidence to the positions of speaker-enunciator in relation do reported PoV, this suggests to a textual-discursive treatment of quoting in academic and scientific text, in a context of teaching that gives attention to the development of communication skills of initial researcher and that can contribute to insert and interact students in the scientific field.

Classificação bibliográfica: as diversas contribuições para o tratamento da informação

PEREIRA, Edinete do Nascimento et al. Classificação bibliográfica: as diversas contribuições para o tratamento da informação. In: SEMINÁRIO DE PESQUISA DO CCSA, 15., 2009. Anais... Natal: UFRN, 2009.

Contribuições da inserção musical para a qualidade de vida no trabalho em ambiente laboral fabril

The present thesis aimed at understanding how the insertion of music in the work environment contributes to achieving Quality of Work Life. - QWL, under the perspective of biopsychosocial and organizational well-being. As to music insertion we considered the theoretical-empirical perception about how music is inserted at work and its functions on such place. The context where the study was taken was the manufacturing area of a major textile company, located in Natal, state of Rio Grande do Norte, Brazil, in which music is used during labor activities. The only study case was the research strategy adopted, with exploratory and descriptive purposes. The primary data were collected through the focus group technique, applied to the collaborator in the manufacturing sector. The semi-structured interview was done as a complementary tool, directed to the supervisor in that sector. Respecting the theoretical saturation criterion, we formed four focus groups, each one composed of eight members randomly selected, among the seventy-six collaborators in the sector. The data were analyzed qualitatively, through the content analysis technique, more specifically the category analysis. We identified twenty-eight QWL attributes. Six of them were found present in the four focus groups and in the interview. Among these ones, the attribute of Interpersonal Relationship at Work, contemplating the Psychological and Organizational dimensions, was the only one anticipated in four out of fifteen theoretical models here listed. The attribute Music at Work Environment could be inserted in the four QWL dimensions, highlighting the power and relevance of this attribute for the research participants. The way music has been inserted in the labor environment contributes to promoting well-being at work, which goes against theoretical conceptions, especially when it comes to musical genre. We identified nine functions of music at work, among which, Improving Work Conditions, Improving Interpersonal Relationship at Work and Favoring Motivation for Work had to be emphasized for being associated to three QWL attributes. In the total, we highlighted seven associations. The most affected QWL dimension through the insertion of music at work was the Psychological one, followed by the Organizational one. We conclude that music insertion provides biological, social and, above all, psychological and organizational well-being to the contributors, thus contributing to obtaining QWL at the labor environment researched. However, we should consider the context and proceed to periodical plans and adjustments in the way of music insertion so as to avoid health and well-being problems to those people at work

Sustentabilidade de empreendimentos econômicos solidários: contribuições e desafios do PITCPES/UFPA a partir da análise da Cooperativa dos Fruticultores de Abaetetuba - COFRUTA

The study aimed to understand how the methodology of hatching contributes to the sustainability of economic enterprises in solidarity. For analysis, we developed a study on the social economy and the incubation methodology, based on the program of teaching, research and extension - Technological Incubator of Popular Cooperatives and Entrepreneurship Solidarity (PITCPES), and as the survey of the Cooperative of Fruit of Abaetetuba - COFRUTA. We started from the exploratory-descriptive approach in a qualitative and quantitative, in order to demonstrate the process of sustainability under the dimensions of different kinds such as: the economic dimension, social dimension, the political dimension, size and scale management training. Based on the analysis of these different dimensions was reached results as: first the recognition that the incubator contributes to the sustainability of COFRUTA, especially with regard to planning, control and the need to diversify production. However, there was suggestion of cooperative for training and technical assistance is continued, to the extent that the performance of projects under the base leaves gaps for the learning and application of social technologies required to the Incubator. It also concluded that the dissertation contributes to the team of the incubator can assess their strengths and weaknesses in their performance