FLAVIO A M CIPPARRONE
@lps.usp.br
Associate Professor
Escola Politécnica da USP
RESEARCH, TEACHING, or OTHER INTERESTS
Engineering, Finance
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Bruno C. F. Pereira, Bruno S. Pereira, Evandro L. S. Teixeira, Armando A. M. Laganá, Flávio A. M. Cipparrone, and Max M. D. Santos
Springer Science and Business Media LLC
Flavio A. M. Cipparrone and Denise Consonni
IEEE Transactions on Education Institute of Electrical and Electronics Engineers (IEEE)
Flavio A. M. Cipparrone, Wesley Beccaro, and Walter Kaiser
Institute of Electrical and Electronics Engineers (IEEE)
Contribution: A didactic methodology, based on analytical expressions and experimental validation, to describe the process of abrupt current interruption in a series RL circuit, that considers real passive components and uses a toggle switch as disconnecting device. Background: In undergraduate courses, circuits adopted in transient analysis usually assume electrical switches in their ideal form, disregarding electrical impedance and its variation over time. Texts and instructors rarely point out these simplifications, so students can become confused. There is thus a need for a suitable switch model that yields a behavior consistent with real devices, while permitting a mathematical formulation of the inductor current. Intended Outcomes: That students should understand electrical component modeling, and how models can represent the physical phenomena that occur in electrical circuits. Application Design: An experiment, designed to evaluate students’ perceptions of switch modeling, modeled a switch by using three different equivalent circuits of increasing complexity, to allow a more realistic simulation. Electrical switch modeling is described, with the models being based on measurements performed on a real circuit. Findings: Student performance was evaluated qualitatively through test scores, and quantitatively through a post-class questionnaire. The results indicate that 96.15% of the students were able to propose an accurate model of the electrical switch.
Sergio R. M. Penedo, Flavio A. M. Cipparrone, and Joao F. Justo
Institute of Electrical and Electronics Engineers (IEEE)
Inpainting methods play a major role in image processing, minimizing the effects of data block loss in image transmission. They analyze primarily the spatial correlation between the portions of an image, usually without explicitly exploring information on the frequency domain. Techniques that evaluate losses of blocks in images do not locally describe a figure of merit for consistent measurement of spatial correlation between pixels of each corrupted block. This investigation presents a digital image inpainting technique, extensible to video applications, using the property of wavelet regularity in multiresolution image analysis, described locally in the sense of Besov vector spaces. Their generalized smoothness allows widespread changes in wavelet coefficients of image data, concealing errors in visual information. This technique estimates decay curves of wavelet coefficients from pixels, based in the observation of the regularity property, correcting pixel blocks contaminated by noise. This investigation proposes an algorithm in the wavelet transform domain, which detects and fixes damaged pixel blocks from a designed decay function for wavelet coefficients. Simulation results, obtained in corrupted images by several noise patterns, indicated better performance of this methodology when compared with other ones.
Flavio AM Cipparrone and Denise Consonni
SAGE Publications
Generalized functions, in particular the Heaviside unit step H( t) and the Dirac delta impulse δ( t), are valuable teaching tools in many contexts of electric circuits. However, engineering undergraduate courses and textbooks normally cover only an introduction to these functions along with their basic properties, without tackling the rigorous mathematical framework of the theory of distributions. In this work, the Heaviside function is used to represent a square wave signal f( t), and the Dirac function appears when the derivative is calculated. The steps for obtaining f ′( t) compare a graphical method with analytical procedures that employ the chain rule. The topic is further extended with the presentation of a theorem and a proposed corollary related to the study of the chain rule applied to general functions involving H( t) and δ( t). Thus, the work provides an appropriate mathematical support for the intuitive graphical method of analysis, which is very familiar in engineering practice.
A. H. Sayed, V. H. Nascimento, and F. A. M. Cipparrone
Society for Industrial & Applied Mathematics (SIAM)
This paper formulates and solves a robust criterion for least-squares designs in the presence of uncertain data. Compared with earlier studies, the proposed criterion incorporates simultaneously both regularization and weighting and applies to a large class of uncertainties. The solution method is based on reducing a vector optimization problem to an equivalent scalar minimization problem of a provably unimodal cost function, thus achieving considerable reduction in computational complexity.
F.A.M. Cipparrone, B. Gustavsen, A. Semlyen, A. Feijoo, and J. Cidras
Institute of Electrical and Electronics Engineers (IEEE)
The author discusses the paper "Enforcing passivity for admittance matrices approximated by rational functions" (see ibid., vol.16, no.1, p.97-104, 2001), requesting some additional information on the passivity enforcement of rational function approximations. The original authors' response is also included in this paper.
H.Y. Kim, F.A.M. Cipparrone, and M.T.C. Andrade
Institution of Engineering and Technology (IET)
A new approach to grey-scale fuzzy mathematical morphology is presented. In this approach, any grey-scale window operator can be constructed using a fuzzy expert system. Many useful operators can be built using a small number of fuzzy rules.