Departamento de Matemática

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https://repositorio.fei.edu.br/handle/FEI/789

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Navegando Departamento de Matemática por Autor "Fábio Gerab"

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    A different statistical approach aiming at EEG parameter investigation for brain machine interface use
    (2014-03-06) DE CASTRO, M. C. F.; Fábio Gerab
    A lot of effort has been made to investigate EEG features that could better represent signal characteristics. The results are usually based on the best mean recognition rates and statistical analysis is done only when different methods are compared. In this work, we propose a new approach that applies multiple rate intercomparisons based on large samples aiming at detecting differences among treatments in order to recognize their importance for the classification rates. Ten frequency band compositions expressed by power spectral density averages were extracted from 8 EEG channels during 4 motor imageries, and spatial feature selections were also considered during the recognition process. Classification rate in large samples can be represented by a normal distribution and, for multiple rate inter-comparisons, the level of significance was corrected based on the Bonferroni Method. The variables were considered to be independents and the test was performed as non paired samples in a very conservative approach. The results showed that there are significant differences among cases of spatial feature selection and thus the considered electrodes are important parameters. On the other hand, considering or not the Delta and Theta bands along with different arrangements for Gamma band resulted in no significant difference. Copyright © 2014 SCITEPRESS - Science and Technology Publications. All rights reserved.
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    Education, school and school mathematics: meanings of the basic education mathematics teachers*
    (2021-01-05) GODOY, E. V.; Fábio Gerab; SANTOS, V. D. M.
    © 2021. All Rights Reserved.The mathematics teacher initial training has been the subject of discussion in the governmental spheres and in the Brazilian Societies of Mathematical Education and of Mathematics. As a consequence of this, we notice advances in some critical points, among which stands out - the excess of academic mathematics disarticulated from the school mathematics; and - the approximation of the mathematics education theoretical-methodological trends with the mathematics undergraduate courses curricular organization. However, there are still absent the conversations involving the different and varied dimensions that interfere in the teaching and learning process of school mathematics; and the different curriculum theories. As a result, the neutrality of mathematical knowledge and the excessive concern with the normative dimension of the curriculum continue being protagonists in the mathematics teacher initial training. In this sense, this article aimed to investigate aspects related to the perception and understanding of basic education mathematics teachers about the school subjects, the school, the school education and about being a math teacher. Methodologically, it is included in a quali-quantitative research approach, in which, in order to achieve the project's objectives, a field research, through a questionnaire available in the “Google docs”, was carried out with the public network mathematics teachers from Sao Paulo state. Theoretically, it was based on studies about curriculum theories. It was tangible that the collaborating teachers are still very attached to the normative dimension of the curriculum, always prioritizing what to teach, how to teach and how to evaluate, without worrying about other dimensions (cultural, social, political) that interfere in the curriculum organization.of the school mathematics.
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    Sustainability reports in Brazil through the lens of signaling, legitimacy and stakeholder theories
    (2017-01-05) Ching, H. Y.; Fábio Gerab
    © 2017 Emerald Publishing Limited.Purpose - The purpose of this paper is to extend the applicability of stakeholder, legitimacy and signaling theories by examining to what extent proactive corporate social responsibility disclosures are interrelated to attempt to gain and maintain legitimacy, to gain support of the stakeholders and to reduce information asymmetry. Design/methodology/approach - To test the theoretical arguments, a longitudinal approach over a five-year period of 145 companies' sustainability reports and statistical analysis was applied to investigate the evolution of their quality. Findings - The results show a significant increase in the quality of sustainability reporting, and the experience gained while writing these reports can contribute to this. Based on signaling and legitimacy theories, this paper suggests that improvement in sustainability reporting quality acts as an important signal to gain legitimacy in case of information asymmetry during the legitimacy process. Th disclosure for economic and social dimensions is better than that of the environmental dimension, and the improvement in quality over time is the because of synergies and interlinkages more between these two dimensions of sustainability, and to a lesser extent because of the environmental dimension. Practical implications - Firms should view investing in sustainability reporting disclosure as a strategy for obtaining business legitimacy. Originality/value - The results of this paper are of interest for several reasons: extend and broaden the use of signaling in studying its use on sustainability reporting; the use of three theories is an appropriate framework for empirical analysis of sustainability reporting disclosure quality in Brazil; and add to the scarce evidence of sustainability reporting in Brazil.