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6th IEEE Latin American Symposium on Circuits and Systems, LASCAS 2015

作者： Borzino, A.M.C.R. Apolinário, J.A. De Campos, M.L.R. Biscainho, L.W.P. Programs of Defense Engineering Rio de Janeiro RJ Brazil Programs of Electrical Engineering Rio de Janeiro RJ Brazil Program of Electrical Engineering COPPE Rio de Janeiro RJ Brazil

ISBN: (纸本)9781479983322

The estimation of the direction of arrival (DOA) of gunshot sounds when the distance between firing and recording sites becomes large, as in a sniper scenario, tends to be degraded by low signal-to-noise ratio. Motivated by its ability to segregate harmonic and percussive parts in music processing, median filtering is used in this work to reduce noise level of gunshot signals prior to the operation of DOA estimation algorithms. Practical experiments with gunshot signals acquired by a microphone array indicate that the proposed pre-processing procedure leads to better results than spectral subtraction. © 2015 IEEE.

关键词： Direction of arrival

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Simulation of MEMS energy harvesting generators based on Bennet's doubler 6

Simulation of MEMS energy harvesting generators based on Ben...

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6th IEEE Latin American Symposium on Circuits and Systems, LASCAS 2015

作者： De Queiroz, Antonio Carlos M. De Oliveira Filho, Luiz Carlos Macedo COPPE/EP Electrical Engineering Program Federal University of Rio de Janeiro Rio de Janeiro Brazil EP-Department of Electronic and Computer Engineering Federal University of Rio de Janeiro Rio de Janeiro Brazil

ISBN: (纸本)9781479983322

This paper presents considerations about the design and operation of electrostatic generators based on Bennet's doubler, when realized with microelectromechanics techniques. electrical models taken from mechanical analogs are used to simulate the devices in operation, with the effects of the mechanical operations and interactions with electrical forces taken into account in the models. From the simulated results, guidelines for the design of the actual systems can be obtained. © 2015 IEEE.

关键词： Electrostatics

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Analysis of the Operation of a Regenerative Electrostatic Energy Harvester

Analysis of the Operation of a Regenerative Electrostatic En...

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IEEE International Symposium on Circuits and Systems

作者： Antonio Carlos M. de Queiroz COPPE/EP - Electrical Engineering Program Federal University of Rio de Janeiro Rio de Janeiro Brazil

ISBN: (纸本)9781479983926

The operation of an electrostatic energy harvester based on the electrostatic generator known as "Bennet's doubler," is analyzed in detail, with the objective of finding the relations of the capacitance values, frequency of operation, and other parameters, with the resulting waveforms and the harvested power when the device is used in conjunction with a DC/DC converter. The results are compared with simulations, and are verified with a macroscopic physical prototype with parameters similar to a microelectromechanical version.

关键词： energy harvesting electrostatic generator low-power circuits

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Neural network design for data compression based on Kernel PCA: Rate-distortion and complexity analysis

Neural network design for data compression based on Kernel P...

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Latin America Congress on Computational Intelligence (LA-CCI)

作者： Vitor R. M. Elias José Gabriel R. C. Gomes Universidade Federal do Rio de Janeiro COPPE – Electrical Engineering Program Rio de Janeiro RJ Brazil

This work presents a study of the properties of a non-linear vector quantization (VQ) method based on Kernel Principal Component Analysis (KPCA), focused on the complexity and viability of implementing this method in image processing. The theory supporting this method is described and then the method is compared to traditional quantization methods, as scalar quantization and entropy-constrained vector quantization. The main characteristics compared are the entropy versus distortion curves, illustrating the quantizers rate-distortion performance, and the complexity associated with the quantization process, as a function of the computational cost required in digital implementation. Finally, this work introduces a complexity-constrained approach to quantizer design.

关键词： Kernel Complexity theory Principal component analysis Mathematical model Vector quantization Covariance matrices

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Computational methods for diagnosability verification of hybrid systems

Computational methods for diagnosability verification of hyb...

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IEEE Conference on Control Technology and Applications (CCTA)

作者： Oumar Diene Marcos V. Moreira Victor R. Alvarez Eduardo R. Silva Department of Electrical Engineering Cidade Universitária Rio de Janeiro RJ Brazil COPPE-Electrical Engineering Program Cidade Universitária Rio de Janeiro RJ Brazil

Modern industrial systems are real time controlled and supervised by means of automatic computer-based control systems, combining discrete and continuous behaviors, and are best modeled as hybrid systems (HS). In this paper, two methods for the verification of the diagnosability of hybrid systems are proposed. The first method is based on the construction of a diagnoser automaton, that can also be straightforwardly used for online diagnosis, and the second method is based on a verifier automaton that, although cannot be used for online diagnosis, can be constructed in polynomial time, leading to a smaller computational complexity for the verification of the diagnosability of HS than the method using diagnoser automata. The main idea of the second method is to build a verifier of the underlying discrete-event system (DES), taking into account the distinguishability of the system modes based on the continuous state models of the HS.

关键词： Automata Yttrium Fault diagnosis Current measurement Control systems Computational modeling Discrete-event systems

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BLIND ESTIMATORS FOR REVERBERATION TIME AND DIRECT-TO-REVERBERANT ENERGY RATIO USING SUBBAND SPEECH DECOMPOSITION

BLIND ESTIMATORS FOR REVERBERATION TIME AND DIRECT-TO-REVERB...

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IEEE Workshop on Applications of Signal Processing to Audio and Acoustics

作者： Thiago de M. Prego Amaro A. de Lima Rafael Zambrano-Lopez Sergio L. Netto Federal Center for Technological Education Celso Suckow da Fonseca Federal University of Rio de Janeiro Electrical Engineering Program-COPPE

ISBN: (纸本)9781479974511

This paper describes algorithms for estimating two important features associated with the reverberation effect on speech signals: the reverberation time and direct-to-reverberant energy ratio. Both methods are referred to as blind algorithms in the sense that they are entirely based on the reverberant signal itself, not depending on the knowledge of the clean original signal. Proposed schemes use subband analysis to generate more and more reliable information, which is post-processed using basic statistical analysis to provide the desired estimate for each particular feature. Modifications on the original estimation algorithms are introduced to cope with lower SNRs. Performance of both algorithms is assessed under the ACE Challenge scope, which included a set of 288 speech signals for training and 4500 signals for final test. Results indicate the effectiveness of both techniques particularly in high-SNR situations.

关键词： Blind estimation Reverberation time Direct-to-reverberant energy ratio Subband analysis

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${{\bf L}_1}$-Constrained Normalized LMS Algorithms for Adaptive Beamforming

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IEEE Transactions on Signal Processing 2015年第24期63卷 6524-6539页

作者： José Francisco de Andrade Marcello L. R. de Campos José Antonio Apolinário Program of Electrical Engineering (PEE) Federal University of Rio de Janeiro (UFRJ) ET-PROSUB Marine Bresilienne (Brazilian Navy Technical Office in France) HOUILLES France Electrical Engineering Program—COPPE/UFRJ Rio de Janeiro RJ Brazil Department of Electrical Engineering (SE/3)—Lab Instituto Militar de Engenharia Praça General Tibúrcio Brazil

We detail in this paper an L 1 -norm Linearly constrained normalized least-mean-square (L 1 -CNLMS) algorithm and its weighted version (L 1 -WCNLMS) applied to solve problems whose solutions have some degree of sparsity, such as the beamforming problem in uniform linear arrays, standard hexagonal arrays, and (non-standard) hexagonal antenna arrays. In addition to the linear constraints present in the CNLMS algorithm, the L 1 -WCNLMS and the L 1 -CNLMS algorithms take into account an L 1 -norm penalty on the filter coefficients, which results in sparse solutions producing thinned arrays. The effectiveness of both algorithms is demonstrated via computer simulations. When employing these algorithms to antenna array problems, the resulting effect due to the L 1 -norm constraint is perceived as a large aperture array with few active elements. Although this work focuses the algorithm on antenna array synthesis, its application is not limited to them, i.e., the L 1 -CNLMS is suitable to solve other problems like sparse system identification and signal reconstruction, where the weighted version, the L 1 -WCNLMS algorithm, presents superior performance compared to the L 1 -CNLMS algorithm.

关键词： Signal processing algorithms Antenna arrays Least mean square algorithms Convergence Array signal processing Sensor arrays

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Online fault diagnosis of modular discrete-event systems

Online fault diagnosis of modular discrete-event systems

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IEEE Annual Conference on Decision and Control

作者： Felipe G. Cabral Marcos V. Moreira Oumar Diene COPPE-Electrical Engineering Program Federal University of Rio de Janeiro Cidade Universitaria Ilha do Fundao Rio de Janeiro 21.945-970 RJ Brazil

ISBN: (纸本)9781479978878

In general, systems are formed by the composition of several modules, local components or subsystems, and may exhibit a large number of states. The growth of the global system model with the number of system components leads to high computational costs for diagnosis techniques based on the global model. In order to circumvent this problem, several works in the literature address the problem of modular fault diagnosis of discrete event systems. In these works, the computation of the global system model is avoided, and the diagnosability of the language of the system is inferred from the behavior of its components. In this paper, a new approach to online diagnosis of modular systems is presented. The method is based on the computation of a Petri net diagnoser, called as synchronized Petri net diagnoser (SPND), that is constructed from the nonfaulty behavior of the modules of the system. We also introduce the definition of synchronous diagnosability of the language of a modular system with respect to the languages of its modules, and present an algorithm to verify this property.

关键词： Petri nets Fault diagnosis Computational modeling Automata Discrete-event systems Synchronization Observers

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Modelling and extremum seeking control of gas lifted oil wells 2

Modelling and extremum seeking control of gas lifted oil wel...

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2nd IFAC Workshop on Automatic Control in Offshore Oil and Gas Production, OOGP 2015

作者： Peixoto, Alessandro Jacoud Pereira-Dias, Diego Xaud, Arthur F. S. Secchi, Argimiro Resende PEE/GOPPE/UFRJ Department of Electrical Engineering P.O. BOX 68.504 Rio de Janeiro RJ21.945-970 Brazil Non-Destructive Testing Corrosion and Welding Laboratory Rio de Janeiro RJ21.945-480 Brazil PEQ/COPPE/UFRJ - Chemical Engineering Program P.O. BOX 68502 Rio de Janeiro RJ21.941-914 Brazil

This paper addresses the design of a perturbation-based extremum seeking control (ESC) method to maintain the oil production around the optimum point of the well-performance curve in gas lifted wells. The method uses periodic perturbation which is injected into the plant with intention to extract the information about the gradient of the well-performance curve. A simple nonlinear dynamic model is proposed and the essential dynamics of the Eikrem's model are captured, i.e., the transient behavior and the optimal steady state wellperformance curve. Based on this simple model, a pre-compensation is developed which allows the application of the ESC scheme without reducing excessively the perturbation frequency. The control performance is evaluated via numerical simulations using an appropriate environment for modelling, simulation and optimization (EMSO) of process dynamic systems. © 2015, IFAG (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

关键词： Process control

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Robust codiagnosability of discrete-event systems against permanent loss of observations

Robust codiagnosability of discrete-event systems against pe...

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IEEE International Conference on Automation Science and engineering (CASE)

作者： Jean H. A. Tomola Marcos V. Moreira João C. Basilio Lilian K. Carvalho Universidade Federal do Rio de Janeiro Rio de Janeiro RJ BR COPPE- Electrical Engineering Program Cidade Universitária Rio de Janeiro RJ Brazil

Different notions of robust diagnosability of discrete-event systems (DESs) have been introduced in the literature. In all these works, the objective is the detection of unobservable fault events in DESs subject to uncertainties in the observation of the events and/or in the plant model. Recently, the so-called robust diagnosability of DESs against permanent loss of observations (RDPLO) has been introduced, where the uncertainty is in the observable event set of the system. In this regard, the language generated by the system is said to be robustly diagnosable if it is possible to detect the fault occurrence, within a bounded delay, even when some sensors permanently fail to communicate the occurrence of the events to the diagnoser. In this paper, we extend the definition of RDPLO to the decentralized case leading to the definition of robust codiagnosability against permanent loss of observations (RCPLO). The paper also addresses the issue of online implementation, and we propose an efficient scheme to carry out online robust codiagnosis against permanent loss of observations. Another contribution of the paper is the development of a polynomial time algorithm for the verification of the RCPLO.

关键词： Robustness Automata Nickel Sensors Fault diagnosis Discrete-event systems Uncertainty

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