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Singular spectrum analysis – an automatic detection technique for mean scatterer spacing estimation using ultrasound signals

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Research on Biomedical engineering 2025年第2期41卷 1-16页

作者： Kauati, Adriana Cortela, Guillermo de Campos, Marcello L. R. Pereira, Wagner C. A. Programa de Pós-graduação em Engenharia Elétrica e Computação – CECE/UNIOESTE PR Foz do Iguaçu85870 650 Brazil Laboratorio de Acústica Ultrasónora – FCien/UdelaR Montevideo Uruguay Electrical Engineering Program – COPPE/UFRJ RJ Rio de Janeiro21941 - 914 Brazil Biomedical Engineering Program – COPPE/UFRJ RJ Rio de Janeiro21941 - 914 Brazil

Purpose: The article proposes an automated method for estimating mean scatterer spacing (MSS) in biological tissues using ultrasound signals. It employs singular spectrum analysis (SSA) with a novel entropy-based criterion to enhance accuracy and eliminate the need for manual parameter tuning. The method is validated using both simulated and real signals, demonstrating its effectiveness in detecting microstructural changes in tissues. Methods: The proposed SSA + entropy method estimates the MSS from ultrasound signals using SSA combined with a relative entropy-based criterion. This approach determines the optimal number of eigenvector pairs to reconstruct the periodic part of the signal by identifying the minimum in the entropy curve—a point that corresponds to the number of underlying periodic components, even in noisy conditions. For experimental validation, ex vivo bovine skeletal muscle was analyzed. RF data were collected at a controlled temperature of using a 3.5-MHz transducer. The MSS results obtained via SSA were also independently verified using microscopy and image analysis of muscle fiber spacing, confirming the effectiveness of the entropy-based SSA approach. Results: The MSS estimation method's accuracy decreases as jitter or Ad noise levels increase, with the method performing well when the estimated MSS is within 10% of the true value. Additionally, the standard deviation of MSS estimates increases as Ad levels and jitter values rise. In phantom experiments, MSS was measured using different transducer frequencies with varying results at each frequency. When applied to ex vivo bovine skeletal muscle tissue, the MSS estimation was validated using both RF and imaging methods, with three consistent groups of MSS values observed, confirming the method's applicability and reliability. Conclusion: The proposed method combines SSA and entropy to automatically estimate medium periodicity in ultrasound, eliminating the need for operator intervention. It succes

关键词： Image analysis

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FIR FILTERS USING INTERPOLATED PREFILTERS AND EQUALIZERS

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS 1990年第1期37卷 17-23页

作者： CABEZAS, JCE DINIZ, PSR Program of Electrical Engineering COPPE/Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil

Novel digital FIR (finite-impulse-response) prefilter structures with periodic impulse response are introduced. The prefilter consists of an interpolated recursive running sum coupled to a nonrecursive structure. By appropriately cascading these prefilters, large stopband attenuation can be obtained, relieving the task of the equalizer. A systematic design procedure for the cascade of prefilters and the equalizer is given, leading to computationally efficient FIR filters. The procedure is based on combining the prefilter-equalizer concepts of J.W. Adams and A.N. Wilson, Jr. (1983) with the IFIR (interpolated FIR) concepts of Y. Neuvo et al. (1987). Design examples are included, demonstrating that the proposed design procedure leads to significant savings in the number of arithmetic operations as compared to recently proposed designs.

关键词： FIR filters design process Prefilters IMPULSE RESPONSE Equalizers HELIOS DEVICES

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TRIDIAGONAL STATE-SPACE DIGITAL-FILTER STRUCTURES

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS 1990年第6期37卷 818-824页

作者： SARCINELLI, FM DINIZ, PSR Program of Electrical Engineering COPPE/Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil

A synthesis, procedure for tridiagonal state-space structures is presented that yields structures with a reduced number of multipliers and eliminates zero-input and constant-input limit cycles. The output roundoff noise is minimized by optimizing some free parameters. Some design examples are presented illustrating the synthesis procedure.< >

关键词： Limit-cycles Digital filters Lattices Narrowband Computational complexity Sufficient conditions Iterative methods Equations Circuits and systems Transfer functions

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A Study on Refractive index sensor based on polished plastic optical fiber

A Study on Refractive index sensor based on polished plastic...

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Latin America Optics and Photonics Conference, LAOP 2022

作者： Sousa, Andre D. Werneck, Marcelo M. Allil, Regina C. Electrical Engineering Program Photonics and Instrumentation Laboratory COPPE UFRJ Brazil

This work presents a theoretical and experimental study based on a polished plastic optical fiber sensor. The sensor sensitivity was 1363 %/RIU in a range of 1.33 to 1.38, showing a correlation with the theoretical an... 详细信息

ISBN: (纸本)9781957171135

关键词： Plastic optical fibers

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Assessment of Offshore Wind Turbine Controls for Integration with Offshore Oil & Gas Platforms 4

Assessment of Offshore Wind Turbine Controls for Integration...

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4th International Conference on Smart Grid and Renewable Energy, SGRE 2024

作者： Amaral, Joao M. T. Ramos, Janito S. Emmerik, Emanuel L. Van Dias, Robson F. S. Electrical Engineering Program COPPE/UFRJ Rio de Janeiro Brazil

ISBN: (纸本)9798350306262

This paper introduces a Controller Hardware-in-the-Loop (CHIL) setup to explore the integration of an Offshore Wind Power Plant (WPP) with an Oil & Gas platform. The platform is represented through a model of its power generation system, which comprises a Gas Turbine (GT) employing the Rowen Model. The loads are modeled using a passive diode rectifier and a controllable load. The WPP incorporates a Type-4 Wind Turbine Generator (WTG) equipped with a full-scale Back-to-Back (BTB) Converter and two distinct control philosophies. The first control philosophy follows the Grid-Following (GFL) approach, reminiscent of older control systems that tend to degrade power quality within power grids. The second philosophy employs a Grid-Forming (GFM) strategy, which can help to mitigate the adverse effects of integrating Renewable Energy Sources (RES). The power system's behavior is simulated using the Real-Time Simulator (RTS) HIL 602+ from Typhoon-HIL, with the control strategies implemented in the Digital Signal Processor (DSP) TMS320F28379D - F28379D LaunchPad of Texas Instruments (TI). The validity of the CHIL setup is verified through load step tests, assessing the performance of the control systems. The results from the tests reveal that the GFM control strategy can enhance the system stability while also providing valuable ancillary services such as frequency and voltage regulation. © 2024 IEEE.

关键词： Power quality

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Blind estimation of reverberation time by neural networks 23

Blind estimation of reverberation time by neural networks

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23rd International Congress on Acoustics: Integrating 4th EAA Euroregio, ICA 2019

作者： Prates, Rodrigo L. Petraglia, Mariane R. Torres, Julio C.B. Petraglia, Antonio Program of Electrical Engineering COPPE Federal University of Rio de Janeiro Brazil

ISBN: (纸本)9783939296157

In this paper we investigate a procedure for blind estimation of room reverberation time, that is, without a priori knowledge of the room impulse response. A neural network based method is proposed, which is robust to noise and to abrupt variations over time of the acquired signal. The input features of the neural network are calculated in the frequency domain, where training samples are generated in the Mel scale. A competent network architecture (i.e., with appropriate number and type of hidden layers and number of neurons comprising each layer), as well as the best training algorithm and regularization technique, are investigated. The use of cross-entropy error during training gives better results than those obtained by mean squared error. Comparative results are presented, considering two previously proposed blind methods: a deep neural network technique and a spectral decay distribution method. © 2019 Proceedings of the International Congress on Acoustics. All rights reserved.

关键词： Neural Network Power Spectral Density Reverberation Time

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Artificial Intelligence (AI) applied to waste management: A contingency measure to fill out the lack of information resulting from restrictions on field sampling

Waste Management Bulletin

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Waste Management Bulletin 2023年第3期1卷 11-17页

作者： Pinhal Luqueci Thomaz, Igor Fernando Mahler, Claudio Pereira Calôba, Luiz Civil Engineering Program COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil Electrical Engineering Program COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil

Waste characterization is essential in planning to reduce waste, create recycling programs and properly use public funds. Traditionally, waste characterization is successfully performed by on-site sampling. This monitoring requires specialized professionals following safety protocols to decrease the health risks associated with the waste handling. However, on-site sampling is susceptible to restrictions in mandatory quarantine situations. Here we show the possibility of using Artificial Intelligence applied to waste management. We identified an Artificial Neural Network (ANN) model fed by combination of population, Gross Domestic Product, Potable Water Supply and Sanitation System data that could be used to fill gaps related to the pandemic period. The modified model predictions were successful due to the adaptive capacity of the ANN-based models. Our results demonstrate that ANN can be used in contingency plans to predict the gravimetric composition and specific weight of Municipal Solid Waste, based on strategically chosen socioeconomic information. We anticipate that our model will be a starting point for more sophisticated computational models. It will allow not only the filling of gaps but also the use for auditing, because it allows analyzing the consistency of gravimetric composition and specific weight data provided by third parties. © 2023 The Authors

关键词： Artificial Neural Network Characterization Municipal Solid Waste Pandemic Socioeconomic factors

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Affine modeling for the complexity of vector quantizers

Affine modeling for the complexity of vector quantizers

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2009 Data Compression Conference, DCC 2009

作者： Seraco, Estevan P. Gomes, José Gabriel R. C. Universidade Federal do Rio de Janeiro COPPE Electrical Engineering Program Brazil

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Perceptual improvement of a two-stage algorithm for speech dereverberation

Perceptual improvement of a two-stage algorithm for speech d...

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12th Annual Conference of the International Speech Communication Association, INTERSPEECH 2011

作者： De Prego, Thiago M. De Lima, Amaro A. Netto, Sergio L. Program of Electrical Engineering COPPE Federal University of Rio de Janeiro Brazil Brazil

This paper presents three effective proposals for a twostage algorithm for one-microphone reverberant speech enhancement. The original algorithm is divided into two blocks: one that deals with the coloration effect, due to the early reflections, and the other for reducing the long-term reverberation. The proposed modifications consider changing the linearprediction model order, the adaptation stepsize and stop criterion for the first algorithm stage. All the modifications are evaluated by a perceptual-quality measure specific for the speechreverberation context. Experimental results for a 200-signal database show that the proposed improvements yielded an increase of 12% in perceptual measure and a reduction of about 96% in the computation cost when compared to the original framework. Copyright © 2011 ISCA.

关键词： Reverberation

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A 0.8 μm CMOS switched-capacitor video filter

A 0.8 μm CMOS switched-capacitor video filter

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Proceedings - 17th Symposium on Integrated Cicuits and Systems Design, SBCCI2004

作者： Petraglia, Antonio Cañive, Jorge Morales Petraglia, Mariane Rembold Program of Electrical Engineering COPPE/EPOLI/UFRJ CP 68504 21945-970 RJ Brazil

ISBN: (纸本)1581139470

The very low sensitivity properties of switched-capacitor filtering structures implemented as a parallel connection of two allpass sections has already been demonstrated theoretically and verified by computer simulation. This paper describes the design of a fifth-order lowpass elliptic filter using this technique, to satisfy specifications commonly used in video frequency applications. Operating with a sampling frequency of 16 MHz, the IC prototype was implemented in a standard double-poly CMOS 0.8 μm process. The experimental results obtained with the fabricated IC showed a passband frequency deviation smaller than 0.08 dB up to the passband edge frequency of 3.4 MHz, and an output noise power of 0.97 μVRMS/√Hz, resulting in a dynamic range of 49.1 dB.

关键词： Switched filters

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