Showing papers by "Moises V. Ribeiro published in 2003"
13 Jul 2003
TL;DR: A new waveform coding technique, based on wavelet transform, for power quality monitoring purposes, that presents a complete adaptive signal processing approach to estimate the fundamental sinusoidal component and separate it from the transient ones in the monitored signal.
Abstract: This paper introduces a new waveform coding technique, based on wavelet transform, for power quality monitoring purposes. The proposed enhanced data compression method (EDCM) presents a complete adaptive signal processing approach to estimate the fundamental sinusoidal component and separate it from the transient ones in the monitored signal. When these nonstationary components are submitted to the compression technique, the sparse representation property of the wavelet transform provides an improvement in the compression ratio. Also, the degradation inserted by the lossy compression process is minimized. Simulation results confirm the effectiveness of the proposed method when compared to the standard solution, characterized by the compression of the whole monitored signal.
15 citations
09 Jun 2003
TL;DR: The results obtained from real database report that the combination of the adaptive signal processing techniques, DWT, MLT and parameters extraction techniques provide a reliable signature of the power quality problems.
Abstract: This paper focuses on digital signal processing techniques applied to power quality problem detection and identification. The detection and identification are based on a previous estimation of the fundamental component of the event under analysis by using the adaptive notch filter and Kalman filter for frequency, amplitude and phase estimations, respectively. After that, the non-stationary type signal, obtained by the subtraction of the estimated fundamental component from the acquired signal, is submitted to the discrete wavelet transform (DWT) and modulated lapped transform (MLT) for further parameters extraction. A set of information or event signature obtained from the transient event is comprised of several parameters extracted from the DWT and MLT domains, the estimated parameters of the fundamental component as well as THD of the transient event. The results obtained from real database report that the combination of the adaptive signal processing techniques, DWT, MLT and parameters extraction techniques provide a reliable signature of the power quality problems.
11 citations
09 Jun 2003
TL;DR: The Fuzzy-DFE-LMS technique applied to minimize both influences of the intersymbol interferences and impulsive noises shows better results than the traditional adaptive and previous fuzzy equalizers when the OFDM is employed as a multicarrier transmission technique.
Abstract: This paper presents the DFE-Fuzzy-LMS and DFE-Fuzzy-RLS algorithms for equalization of power line channels (PLC) and for the improvement on the data transmission rates. Both proposals are DFE (decision feedback equalizer) versions of the adaptative singleton type 1 fuzzy algorithms initially proposed by J.M. Mendel. One of the most important characteristics of the proposals are their inherent capability to equalizer minimum, non-minimum and maximum phase channels and deal with higher power impulsive noises. The impulsive noise is one of the major problems concerning PLC channels. The Fuzzy-DFE-LMS technique applied to minimize both influences of the intersymbol interferences and impulsive noises shows better results than the traditional adaptive and previous fuzzy equalizers when the OFDM is employed as a multicarrier transmission technique.
7 citations