Um sistema inteligente de classificação de sinais de EEG para Interface Cérebro-Computador

The Brain-Computer Interfaces (BCI) have as main purpose to establish a communication path with the central nervous system (CNS) independently from the standard pathway (nervous, muscles), aiming to control a device. The main objective of the current research is to develop an off-line BCI that separates the different EEG patterns resulting from strictly mental tasks performed by an experimental subject, comparing the effectiveness of different signal-preprocessing approaches. We also tested different classification approaches: all versus all, one versus one and a hierarchic classification approach. No preprocessing techniques were found able to improve the system performance. Furthermore, the hierarchic approach proved to be capable to produce results above the expected by literature

Uso de funções de alívio para estimar o efeito de chaveamentos corretivos na eliminação de congestionamentos em sistemas de potência

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Controle feedback de nível baseado em sensor de imagem aplicado ao equipamento misturador-decantador à inversão de fases (MDIF®)

The treatment of wastewaters contaminated with oil is of great practical interest and it is fundamental in environmental issues. A relevant process, which has been studied on continuous treatment of contaminated water with oil, is the equipment denominated MDIF® (a mixer-settler based on phase inversion). An important variable during the operation of MDIF® is the water-solvent interface level in the separation section. The control of this level is essential both to avoid the dragging of the solvent during the water removal and improve the extraction efficiency of the oil by the solvent. The measurement of oil-water interface level (in line) is still a hard task. There are few sensors able to measure oil-water interface level in a reliable way. In the case of lab scale systems, there are no interface sensors with compatible dimensions. The objective of this work was to implement a level control system to the organic solvent/water interface level on the equipment MDIF®. The detection of the interface level is based on the acquisition and treatment of images obtained dynamically through a standard camera (webcam). The control strategy was developed to operate in feedback mode, where the level measure obtained by image detection is compared to the desired level and an action is taken on a control valve according to an implemented PID law. A control and data acquisition program was developed in Fortran to accomplish the following tasks: image acquisition; water-solvent interface identification; to perform decisions and send control signals; and to record data in files. Some experimental runs in open-loop were carried out using the MDIF® and random pulse disturbances were applied on the input variable (water outlet flow). The responses of interface level permitted the process identification by transfer models. From these models, the parameters for a PID controller were tuned by direct synthesis and tests in closed-loop were performed. Preliminary results for the feedback loop demonstrated that the sensor and the control strategy developed in this work were suitable for the control of organic solvent-water interface level

Desenvolvimento de um programa de ensino de Física Térmica para o nível médio

Neste trabalho de mestrado, detemos nossa pesquisa na elaboração e implementação de planos de aula, que pudessem contribuir para estimular a participação e o interesse dos alunos nas aulas de física. Utilizamos como principal recurso didático, textos provenientes da Internet, que proporcionasse aos estudantes acesso a leitura envolvendo conteúdos científicos, tentando amenizar a falta de qualquer forma de material didático de ciências para os alunos. Pudemos constatar também, deficiências por parte dos educandos, em atividades que envolviam leitura e interpretação de textos, o que nos preocupou bastante enquanto educador e nos motivou a provocar mudanças neste quadro. As atividades aqui propostas foram elaboradas e aplicadas numa turma do segundo ano do nível médio, atendendo conteúdos de física térmica mas com um enfoque interdisciplinar. Cada plano de aula proporcionou participação ativa de cada estudante, seja na realização de tarefas solicitadas ou na participação de discussões em sala de aula. Os resultados mais expressivos desta pesquisa foram aumento na participação dos alunos nas atividades fora e dentro da classe e uma mudança na forma de pensar e elaborar soluções para determinados problemas

Investigação histórica na formação de professores de matemática: um estudo centrado no conceito de função

In this study we analyzed the development of a teaching experience, involving students with a bachelor s degree in mathematics from UFRN, based on the history of mathematics and mathematical investigations with the aim of contributing to the improvement of the teaching-learning of mathematics. The historical investigation tasks were planned and applied in the classroom, focusing on functional thought. The results obtained during the experience were described and evaluated based on authors who support the assumption of investigation and history as an alternative to the learning of mathematics. We emphasize that the material of analysis consisted of a work diary, audio recordings, questionnaires with testimony of the students involved, and, in addition, the assessment of the teacher of that subject. With regard to the mathematical content, the study was restricted to the concept of function, forms of representation and notation. It was evident that students showed great improvement with regard to the necessary formalization of the mathematical contents which were focused on, and to the active involvement of the students at different stages of the study. We can affirm that the completed study certainly represents significant contributions to an approach in the teaching-learning of functional thought

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

Ambiente de textualização no ensino a distância: o caso do fórum educacional

This research deals with textualization issues present in educational forums in distance learning environment. The research aims to analyze textualization regarding communication practices between tutors and distance learning students. Specifically the research aims to verify if the educational forum is considered pertinent for knowledge construction as well as identify subject´s behavior in e-Proinfo environment. The research also aims to understand the dynamics of the teaching and learning techniques related to the forum´s printed material. This is done in order to acknowledge discourse on behalf of subjects through the presented educational assignments. In order to address the issue, the work dealt with the relations present in distance learning forums, the forms in which the assignments are made, the way social actors interact and how this debate happens in the virtual environment. The research emphasized an educational forum used in a higher education institution at Rio Grande do Norte/Brazil. Thus the research corpus is composed by messages that were posted in the forum in the module called computer material . This module is one of the last in a set of six modules that are part of The Basic Cycle for Media Training promoted by the Center for Distance Learning in a public university at Rio Grande do Norte/Brazil. The research deals with a qualitative type approach in the perspectives of Merriam (1988), Cresswell (1994) and Minayo (1996). In order to achieve this analysis, the research dealt with theoretical landmarks related to distance learning present in (Silva, 2008; Brait, 1993; Sperbe and Wilson, 1986; Marquesi and Elias 2008 as well as Xavier, 2005, amongst others. As for aspects related to media and technological perspectives present in the forum, the research dealt with (Baranov, 1989; Neuner, 1981; Kearsley and Moore, 1996). Textualization was dealt according to (Marcuschi, 2008; Costa Val, 2004) and the conceptions and functions regarding tutors was seen according to (Salgado, 2002). In the conclusion and recommendations it was seen that these discussions present relevant contributions to distance learning and go beyond the practical universe present in electronical interaction. In the final considerations it is pointed out that this research is relevant for areas such as applied linguistics and presents guidelines for those involved in continuous education and aim meaningful knowledge that is coherent with distance learning education

Narrativas de professores em formação sobre a didatização de podcasts para o ensino de inglês na floresta

Considering the following conditions: (1) the fluency demands of students in an undergraduate program in Languages and Literatures/English in the Amazon region; (2) the listening and speaking needs of pre-service teachers of English as a Foreign Language (EFL); (3) my continuing education as a professor of EFL and my academic literacy as a teacher-researcher and pre-service-teacher trainer, this study, which is based on Narrative Inquiry, reports on a teacher experience of working didactically with oral genres through podcasting an activity that emerged with the advent of Information and Communication Technology (ICT). Through this process, I engage with some theorists who promote teaching as a process that is driven by a concept of language as social practice. Subsequently, I make use of the notions of context of culture and context of situation, derived from Systemic Functional Linguistics, as well as the concept of genre and register derived from the perspective of this theory. Based on these principles and beliefs, the Amazon region constitutes the register (situation) of the genres used in this study. These principles also provide, opportunities for building learning strategies appropriate to this local context, and also to teach listening and speaking skills from a task-based approach. During the experience, based on the reflective teacher-education model, the participants produced narratives about the process, which I then analyzed according to Ely, Vinz, Downing and Anzul (2001), who propose possibilities of composing meanings in Narrative Inquiry. Based on this perspective, I discuss the following topics, which were highly emphasized in the participants narratives: the lack of didactic activities using oral genres; the relevance of context within teacher education; and collaborative work as a strategy to overcome gaps in digital literacy, language fluency and teaching skills. The meanings I thereby compose point to a paradigm shift in English language teaching within this context. I also argue for a pedagogical practice that is engaged with historical and socio-cultural issues, and with the development of language skills, also one that promotes the implementation of ICTs at the very start of teacher training programs, adopting teaching and learning strategies that correspond to the demands of fluency in this particular context, and deficiencies imposed by geographical isolation

Didática do plurilinguismo: efeitos da intercompreensão de línguas românicas na compreensão de textos escritos em português

This exploratory study aims to present some readings as Doyé (2003), Carrasco Perea (2003), Melo Araújo e Sá (2004), Chavagne (2009) and Alas-Martins (2010; 2011) which helped to confirm some ways for showing that a plurilingual environment can enable a trend in improving the understanding of written texts in the mother tongue, and can collaborate on a better perception of the world around a person with all their different nuances. The study describes the methodology and some results of our doctoral research that resulted in the insertion of the experimental discipline called Intercomprehension of Romanic Languages (ILR) in the curriculum in the city of Natal / RN / Brazil, and it was justified because of high functional illiteracy degree among young people up to 15 years old according to the educational data from IBGE research on 2010. The results were verified through an experimental action-research which was characterized by Lewin (1946); Nunan (1992); Thiollent (1994) and Trip (2005) in two schools: Professoara Terezinha Paulino de Lima (municipal school) and Professora Ana Julia de Carvalho Mousinho (State of Rio Grande do Norte), with 95 students from the final years of primary education. The corpus of this research was subjected to a series of condensed techniques like the nonparametric test from Kruskal and Wallis (1952) and the parametric test ANOVA as an effort to provide statistical significance to the analysis of the results indicated in the book of ILR activities. The research presented some skill views about reading comprehension of written texts according to perspective of Ringbow (1987), Giacobbe (1990), Alarcão (1991; 2009a and 2009b), Corder (1992), Castellotti (2001) and Degache (2003), and the possibilities of transfer these skills for learning Portuguese as pointed out by Meissner, Klein and Stegmann (2004); it indicates a positive trend towards the understanding of LM according to analyzing the scores of written tests and texts by participants in solving tasks

Análise sísmica usando transformada de Curvelet

Oil prospecting is one of most complex and important features of oil industry Direct prospecting methods like drilling well logs are very expensive, in consequence indirect methods are preferred. Among the indirect prospecting techniques the seismic imaging is a relevant method. Seismic method is based on artificial seismic waves that are generated, go through the geologic medium suffering diffraction and reflexion and return to the surface where they are recorded and analyzed to construct seismograms. However, the seismogram contains not only actual geologic information, but also noise, and one of the main components of the noise is the ground roll. Noise attenuation is essential for a good geologic interpretation of the seismogram. It is common to study seismograms by using time-frequency transformations that map the seismic signal into a frequency space where it is easier to remove or attenuate noise. After that, data is reconstructed in the original space in such a way that geologic structures are shown in more detail. In addition, the curvelet transform is a new and effective spectral transformation that have been used in the analysis of complex data. In this work, we employ the curvelet transform to represent geologic data using basis functions that are directional in space. This particular basis can represent more effectively two dimensional objects with contours and lines. The curvelet analysis maps real space into frequencies scales and angular sectors in such way that we can distinguish in detail the sub-spaces where is the noise and remove the coefficients corresponding to the undesired data. In this work we develop and apply the denoising analysis to remove the ground roll of seismograms. We apply this technique to a artificial seismogram and to a real one. In both cases we obtain a good noise attenuation

Efeitos do treinamento de dupla tarefa no controle do equilíbrio dinâmico e estático de idosas pré-frágeis: um estudo piloto

The increasing world population of older individuals has become a subject of growing research for prevention and reversibility of the frailty because it is a major risk factor for the occurrence of falls, especially when it involves everyday situations of dual task. Some rehabilitation programs have already used the methods of dual-task with general exercises for improving gait and postural control, but has been reported that these interventions have little specificity with limited success to improve certain aspects of static and dynamic position during the performance of functional tasks. This study aimed to verify the measures of postural control in a group of elderly women with fragility phenotype after physical therapy intervention program based on dual-task treadmill training. We selected six pre-frail elderly subjects, with a minimum age of 65, female, living in the community and randomly assigned to two groups. The survey was conducted twice a week for 45 minutes, for four weeks. The simple task intervention consisted only in training on a treadmill and the dual task consisted of in treadmill training associated with visual stimuli. The assessments were made with the use of the Berg Balance Scale (BBS) and the Balance Master® computerized posturography, static and dynamically. The effects of retention were observed after one month, using the same instruments earlier used. The results showed a tendency toward improvement or maintenance of the balance after training on a treadmill, especially with respect to static equilibrium. Both groups showed the most notable changes in the variables related to gait, as the length and speed. The BBS scores and the baropodometric variables showed that the experimental group could keep all values similar or better even one month after completion of training unlike the control group. We concluded that the dual-task performance had no additional value in relation to the improvement of balance in general, but we observed that the effectiveness of visual stimulation occurred in the maintenance of short term balancevariables

Apoio social e síndrome da fragilidade em idosos residentes na comunidade

Introduction: The frailty in the elderly is the result of a complex interplay between many social and clinical factors involved in its genesis. Although there is an understanding of its association with increased risk of adverse clinical outcomes, still it is unclear whether this syndrome can be aggravated due to lack of social support. So, the objective of this study was to analyze the association between social support and frailty syndrome in elderly community residents. Materials and methods: Observational analytical cross-sectional study, with a sample of 300 elderly living in the city of Natal-RN. Were collected informations about socialdemographic, economics and physical health data. The Social support was assessed by the status of cohabitation; marital status; contact frequency and diversity rate; received and given attendance frequency rate; and Map Minimum Relations of the Elderly. The frailty was assessed using the following criteria: unintentional weight loss, weakness, low physical activity, exhaustion and Slowness. To observe any possible associations, we performed the Pearson chi-square test, the Student t test and multivariate analysis using binary logistic regression, adopting a significance level of 5%. Results: It was observed that there were no associations of frailty with the social support variables, except for housekeeping mode (p = 0.046) of the MMRI. For the sociodemographic, economic, physical health and social support data, only age (p <0.001), sedentary lifestyle (p = 0.002) and poor perceived health (p = 0.001) were the ones that remained in the logistic regression model, with strong association for the presence of frailty. Conclusion: Among the variables related to social support, only to help with housekeeping was significantly associated with frailty. However, more studies need to be developed to characterize the social vulnerability, as well as health services need to recognize the importance of social support as an integral part of care for the elderly

Efeitos do treino em esteira na marcha com dupla tarefa de indivíduos com doença de Parkinson: ensaio clínico controlado randomizado

Background: The gait automaticity loss difficults realization of concurrent activities - Dual Task (DT). In these situations, individuals with Parkinson`s disease (PD) show a significant reduction in gait velocity and stride length, as strides variability and asymmetry increased, factors predisposing to falls. However, recent studies have shown that training involving DT may cause subsequent improvements in gait variables with DT in individuals with PD. The treadmill use was adopted by this study, by promoting greater regularity in step and enhance training. Objective:To investigate immediate effects of gait training associated with cognitive tasks on gait in individuals with PD. Methods: Twenty-two volunteers were randomly divided into two groups: control group (n = 11), who performed gait training on a treadmill for 20 minutes, and the experimental group (n = 11), who performed treadmill gait training for 20 minutes associated with cognitive tasks of verbal fluency, memory, and spatial planning. Participants were evaluated in phase on of antiparkinsonian medication as the demographic, clinical and anthropometric (identification form), cognitive status (Montreal Cognitive Assessment - MoCA), executive function (Frontal Assessment Battery), level of physical disability (Hoehn and Yahr Modified), motor and functional status (Unified Rating Scale for Parkinson`s Disease - UPDRS), and kinematics (Qualisys Motion Capture System). Results: There were not differences between groups, but both showed improvement after the intervention. The control group had an increase in velocity (p = 0.008), stride length (p = 0.04), step length (p = 0.02) and decreased double support time(p = 0.03). The experimental group showed an increase in speed (p = 0.002), stride length (p = 0.008), step length (p = 0.02) and cadence (p = 0.01), as well as a decrease in the width stride (p = 0.001) and total support time (p = 0.02). As the angular variables, the experimental group had a significant increase in the initial contact angle of ankle (p = 0.01). Conclusion: The gait training combined with cognitive activities didn`t provide significant improvements in gait variables with DT, but this study was the first to demonstrate that gait training on treadmill as simple task minimized the negative interference of DT in PD

Validade e reprodutibilidade do Wii Balance Board para avaliação do equilíbrio vertical estático: um novo método de avaliação.

The Wii Balance Board (WBB) began to be investigated as a low-cost alternative for assessing static balance in vertical posture. However, studies employed methodological procedures that did not eliminate result variability between the tests and equipment used. Objective: Determine the validity and reproducibility of the WBB as an instrument for assessing static balance in the vertical position, using simultaneous data analysis and superimposed equipment. Methods: This is an accuracy study of 29 healthy young individuals of both sexes aged 18 to 30 years. Subjects were assessed 24h apart (test-retest), using unipodal and bipodal support tests, with eyes closed and open. To that end the WBB was placed on top of a force platform (FP) and data (postural sway) were collected simultaneously on both devices. Validity and reproducibility were analyzed using the interclass correlation coefficient (ICC). Finally, Bland-Altman analysis was applied to assess agreement. Results: The sample was composed of 23 women and 6 men, with mean age of 24.2±6.3 years, 60.7±6.3 kg and 1.64±4.2 m. The validity of the WBB compared to the FP was excellent for all 4 tasks proposed (ICC = 0.93 0.98). The reproducibility analyzed by test-retest was excellent for the bipodal support tasks (ICC = 0.93-0.98) and only moderate for the unipodal support tests (ICC = 0.46 0.70). Graphic analysis exhibited good agreement between the devices, since most of the measures were within the limits of agreement. Conclusion: this study proved the validity and reproducibility of the Wii Balance Board as an instrument for assessing static balance in vertical posture, using simultaneous analysis with superimposed equipment. Thus, the WBB has been increasingly used by physical therapists and other health professionals in their clinical practice, as both a rehabilitation and assessment tool

Caracterização dos acoplamentos fase-amplitude na região CA1 do hopocampo

Brain oscillation are not completely independent, but able to interact with each other through cross-frequency coupling (CFC) in at least four different ways: power-to-power, phase-to-phase, phase-to-frequency and phase-to-power. Recent evidence suggests that not only the rhythms per se, but also their interactions are involved in the execution of cognitive tasks, mainly those requiring selective attention, information flow and memory consolidation. It was recently proposed that fast gamma oscillations (60 150 Hz) convey spatial information from the medial entorhinal cortex to the CA1 region of the hippocampus by means of theta (4-12 Hz) phase coupling. Despite these findings, however, little is known about general characteristics of CFCs in several brain regions. In this work we recorded local field potentials using multielectrode arrays aimed at the CA1 region of the dorsal hippocampus for chronic recording. Cross-frequency coupling was evaluated by using comodulogram analysis, a CFC tool recently developted (Tort et al. 2008, Tort et al. 2010). All data analyses were performed using MATLAB (MathWorks Inc). Here we describe two functionally distinct oscillations within the fast gamma frequency range, both coupled to the theta rhythm during active exploration and REM sleep: an oscillation with peak activity at ~80 Hz, and a faster oscillation centered at ~140 Hz. The two oscillations are differentially modulated by the phase of theta depending on the CA1 layer; theta-80 Hz coupling is strongest at stratum lacunosum-moleculare, while theta-140 Hz coupling is strongest at stratum oriens-alveus. This laminar profile suggests that the ~80 Hz oscillation originates from entorhinal cortex inputs to deeper CA1 layers, while the ~140 Hz oscillation reflects CA1 activity in superficial layers. We further show that the ~140 Hz oscillation differs from sharp-wave associated ripple oscillations in several key characteristics. Our results demonstrate the existence of novel theta-associated high-frequency oscillations, and suggest a redefinition of fast gamma oscillations