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IEEE North-East Workshop on Circuits and Systems (IEEE-MWCAS'07)

作者： C. Shahnaz W. P. Zhu M. O. Ahmad Centre for Signal Processing and Communications Department of Electrical and Computer Engineering Concordia University Montreal QUE Canada

In this paper, a bifeature algorithm for the voiced/unvoiced (V/UV) discrimination of noise degraded speech signals is presented. A measure of merit for periodicity, and a normalized low frequency energy ratio are encompassed as two speech features which are proposed to derive from the Linear Prediction (LP) residual of the pre-processed noisy speech. Based on the statistically determined signal-dependent initial-thresholds of the features, a logical and multi-check V/UV classification criterion is developed which is capable of significantly removing the artifacts in the transitional frames between voiced and unvoiced regions. Through Simulation results, a superior performance of the proposed V/UV discrimination scheme for noisy speech has been illustrated compared to some of the existing methods.

关键词： Speech enhancement Low-frequency noise Frequency Speech analysis Additive noise signal processing algorithms Speech processing signal to noise ratio Degradation Energy measurement

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A first-order mechanical device to model traumatized craniovascular biodynamics

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Journal of Medical Devices, Transactions of the ASME 2007年第1期1卷 89-95页

作者： Kohles, Sean S. Mangan, Ryan W. Stan, Edward McNames, James Kohles Bioengineering Portland OR 97214-5135 United States Department of Mechanical and Materials Engineering Portland State University Portland OR 97207-0751 United States Department of Electrical and Computer Engineering Portland State University Portland OR 97207-0751 United States Biomedical Signal Processing Laboratory Department of Electrical and Computer Engineering Portland State University Portland OR 97207-0751 United States Department of Surgery Oregon Health and Science University Portland OR 97239-3098 United States

Mathematical models currently exist that explore the physiology of normal and traumatized intracranial function. Mechanical models are used to assess harsh environments that may potentially cause head injuries. However, few mechanical models are designed to study the adaptive physiologic response to traumatic brain injury. We describe a first-order physical model designed and fabricated to elucidate the complex biomechanical factors associated with dynamic intracranial physiology. The uni-directional flow device can be used to study interactions between the cranium, brain tissue, cerebrospinal fluid, vasculature, blood, and the heart. Solid and fluid materials were selected to simulate key properties of the cranial system. Total constituent volumes (solid and fluid) and volumetric flow (650 ml/min) represent adult human physiology, and the lengths of the individual segments along the flow-path are in accord with Poiseuille's equation. The physical model includes a mechanism to simulate autoregulatory vessel dynamics. Intracranial pressures were measured at multiple locations throughout the model during simulations with and without post-injury brain tissue swelling. Two scenarios were modeled for both cases: Applications of vasodilation/constriction and changes in the head of bed position. Statistical results indicate that all independent variables had significant influence over fluid pressures measured throughout the model (p < 0.0001) including the vasoconstriction mechanism (p=0.0255). The physical model represents a first-order design realization that helps to establish a link between mathematical and mechanical models. Future designs will provide further insight into traumatic head injury and provide a framework for unifying the knowledge gained from mathematical models, injury mechanics, clinical observations, and the response to therapies. Copyright © 2007 by ASME.

关键词： Biomechanics

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Designing an embedded video processing camera using a 16-bit microprocessor for a surveillance system

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Journal of VLSI signal processing Systems for signal, Image, and Video Technology 2006年第1期42卷 57-68页

作者： Sato, Koichi Evans, Brian L. Aggarwal, J.K. Department of Electrical and Computer Engineering Computer and Vision Research Center University of Texas at Austin Austin TX 78712 United States Department of Electrical and Computer Engineering Embedded Signal Processing Laboratory University of Texas at Austin Austin TX 78712 United States Department of Electrical and Computer Engineering University of Texas Austin Design and Implementation of Signal Processing Systems Technical Committee IEEE Signal Processing Society IEEE Department of Electrical and Computer Engineering Computer and Vision Research Center IEEE Computer Society

This paper describes the design and implementation of a hybrid intelligent surveillance system that consists of an embedded system and a personal computer (PC)-based system. The embedded system performs some of the image processing tasks and sends the processed data to the PC. The PC tracks persons and recognizes two-person interactions by using a grayscale side view image sequence captured by a stationary camera. Based on our previous research, we explored the optimum division of tasks between the embedded system and the PC, simulated the embedded system using dataflow models in Ptolemy, and prototyped the embedded system in real-time hardware and software using a 16-bit CISC microprocessor. This embedded system processes one 320 × 240 frame in 89 ms, which yields one-third of the rate of 30 Hz video system. In addition, the real-time embedded system prototype uses 5.7 K bytes of program memory, 854 K bytes of internal data memory and 2 M bytes external DRAM. © Springer Science + Business Media, Inc. 2006.

关键词： Microprocessor chips

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Characterization of anomaly detection in hyperspectral imagery

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Sensor Review 2006年第2期26卷 137-146页

作者： Chang, Chein-I Hsueh, Mingkai Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore MD United States

Purpose - The paper aims to characterize anomaly detection in hyperspectral imagery. Design/methodology/approach - This paper develops an adaptive causal anomaly detector (ACAD) to investigate several issues encountered in hyperspectral image analysis which have not been addressed in the past. It also designs extensive synthetic image-based computer simulations and real image experiments to substantiate the work proposed in this paper. Findings - This paper developed an ACAD and custom-designed computer simulations and real image experiments to successfully address several issues in characterizing anomalies for detection, which are - first, how large size for a target to be considered as an anomaly? Second, how an anomaly responds to its proximity? Third, how sensitive for an anomaly to noise? Finally, how different anomalies to be detected? Additionally, it also demonstrated that the proposed ACAD can be implemented in real time processing and implementation. Originality/value - This paper is the first work on investigation of several issues related to anomaly detection in hyperspectral imagery via extensive synthetic image-based computer simulations and real image experiments. In addition, it also develops a new developed an ACAD to address these issues and substantiate its performance.

关键词： Image processing

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Special Issue on Variable Structure System Control — New Designs and Applications

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Asian Journal of Control 2008年第4期5卷

作者： Prof. Jian-Xin Xu Prof. Leonid Fridman Department of Electrical and Computer Eng. National University of Singapore 4 Engineering Drive 3 Singapore 117576 Tel +65 6874-2566 Fax +65 6779-1103 Dr Jian-Xin Xu received his Bachelor degree from Zhejiang University China in 1982. He attended the University of Tokyo Japan where he received his Master's and Ph.D. degrees in 1986 and 1989 respectively. All his degrees are in Electrical Engineering. He worked for one year in the Hitachi research Laboratory Japan and for more than one year in Ohio State University U.S.A. as a Visiting Scholar. In 1991 he joined the National University of Singapore and is currently an associate professor in the Department of Electrical Engineering. His research interests lie in the fields of learning control variable structure control fuzzy logic control discontinuous signal processing and applications to motion control and process control problems. He is the associate editor of Asian Journal of Control member of TC on variable structure systems and sliding mode control of IEEE Control Systems Society and a senior member of IEEE. He has produced more than 90 peer-refereed journal papers near 160 technical papers in conference proceedings and authored/edited 4 books. Division de Estudios de Posgrado Facultad de Ingenieria National Autonomous University of Mexico DEP-FI UNAM Edificio “A” Circuito Exterior Ciudad Universitaria A. P. 70–256 C.P.04510 Mexico D.F. Mexico Tel +52 55 56223014 Fax +52 55 56161719 Dr. Leonid M. Fridman received his M.S in mathematics from Kuibyshev (Samara) State University Russia Ph.D. in Applied Mathematics from Institute of Control Science (Moscow) and Dr. of Science degrees in Control Science from Moscow State University of Mathematics and Electronics in 1976 1988 and 1998 respectively. In 1976–1999 Dr. Fridman was with the Department of Mathematics at the Samara State Architecture and Civil Engineering Academy Samara Russia. In 2000–2002 he was with the Department of Postgraduate Study and Investigations at the Chihuahu

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Blind source extraction of instantaneous noisy mixtures using a linear predictor

Blind source extraction of instantaneous noisy mixtures usin...

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ISCAS 2006: 2006 IEEE International Symposium on Circuits and Systems

作者： Liu, Wei Mandic, Danilo P. Cichocki, Andrzej Communications Research Group Department of Electronic and Electrical Engineering University of Sheffield United Kingdom Communications and Signal Processing Research Group Department of Electrical and Electronic Engineering Imperial College London United Kingdom Laboratory for Advanced Brain Signal Processing Brain Science Institute RIKEN Japan

ISBN: (纸本)0780393902

The blind source extraction (BSE) problem for noisy measurements is addressed using the linear predictor method. Based on a previously proposed method for the noise-free case, we propose a new cost function with the effect of noise removed. Two novel adaptive algorithms are next introduced, one of which is based on minimisation of the normalised mean square prediction error (MSPE), whereas the other minimises the MSPE using prewhitening followed by regularisation of the demixing vector. The successful operation of these new algorithms requires the knowledge of the correlation matrix of noise. © 2006 IEEE.

关键词： Blind source separation

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Novel Applications of Noise in Sensing and communications

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AIP Conference Proceedings 2007年第1期922卷 405-410页

作者： Laszlo B. Kish Robert Mingesz Zoltan Gingl Gabor Schmera Janusz Smulko Chiman Kwan Peter Heszler Claes‐Goran Granqvist 1Texas A&M University Department of Electrical and Computer Engineering College Station TX 77843‐3128 2University of Szeged Department of Experimental Physics Dom ter 9 Szeged H‐6720 Hungary 3Space and Naval Warfare Systems Center San Diego CA 92152‐5001 4Gdansk University of Technology WETiI ul. G. Narutowicza 11/12 80‐952 Gdansk Poland 5Signal Processing Inc. 13619 Valley Oak Circle Rockville MD 20850 6Research Group of Laser Physics of the Hungarian Academy of Sciences University of Szeged P.O. Box 406 H‐6701 Szeged Hungary 7Department of Engineering Sciences The Ångström Laboratory Uppsala University P.O. Box 534 SE‐751 21 Uppsala Sweden

Recently, it has been shown that excess noises generated or modified by chemical agents can be used to detect and identify chemicals with enhanced sensitivity and selectivity. Moreover thermal noise and its artificial versions (Johnson‐like noises) can be utilized as information carriers with peculiar properties. The first application is called Fluctuation‐Enhanced Sensing. The second class can be called Thermal Noise Informatics with relevant topics are Zero Power Classical Communication and (in the quantum limit) Zero‐Quantum Quantum Communication; Thermal Noise Driven Computing; and Totally Secure Classical Communication. In the paper version of this talk, we will briefly describe the scope of these fields and in the oral talk we also provide extended considerations and results.

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SPC10-4: EM Algorithm for Multiple Wideband Source Localization

SPC10-4: EM Algorithm for Multiple Wideband Source Localizat...

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IEEE Globecom 2006

作者： Kiran K. Mada Hsiao-Chun Wu Communications and Signal Processing Laboratory Department of Electrical and Computer Engineering Louisiana State University USA

A computationally efficient algorithm for multiple source localization, using the expectation-maximization (EM) algorithm, for the wideband sources in the near field of a sensor array/area, is presented. The basic idea is to decompose the observed sensor data, which is a superimposition of multiple sources, into individual components in the frequency domain and then estimate the corresponding location parameters associated with each component separately. Instead of the conventional alternating projection method, we propose to adopt the EM algorithm in this paper; our method involves two steps, namely Expectation (E-step) and Maximization (M-step). In the E-step, the individual incident source waveforms are estimated. Then, in the M-step, the maximum likelihood estimates of the source location parameters are obtained. These two steps are executed iteratively and alternatively until the pre-defined convergence is reached. The computational complexity comparison between our proposed EM algorithm and the existing alternating projection scheme is investigated. It is shown through Monte Carlo simulations that the computational complexity of the proposed EM algorithm is significantly lower than that of the conventional alternating projection algorithm.

关键词： Wideband Sensor arrays Iterative algorithms Computational complexity Frequency domain analysis Frequency estimation Maximum likelihood estimation Position measurement Convergence Projection algorithms

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New radix-(2/spl times/2/spl times/2)/(4/spl times/4/spl times/4) and radix-(2/spl times/2/spl times/2)/(8/spl times/8/spl times/8) DIF FFT algorithms for 3-D DFT

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IEEE Transactions on Circuits and Systems I: Regular Papers 2006年第2期53卷 306-315页

作者： S. Bouguezel M.O. Ahmad M.N.S. Swamy Center for Signal Processing and Communications Department of Electrical and Computer Engineering Concordia University Montreal QUE Canada Canada

In this paper, new three-dimensional (3-D) radix-(2/spl times/2/spl times/2)/(4/spl times/4/spl times/4) and radix-(2/spl times/2/spl times/2)/(8/spl times/8/spl times/8) decimation-in-frequency (DIF) fast Fourier transform (FFT) algorithms are developed and their implementation schemes discussed. The algorithms are developed by introducing the radix-2/4 and radix-2/8 approaches in the computation of the 3-D DFT using the Kronecker product and appropriate index mappings. The butterflies of the proposed algorithms are characterized by simple closed-form expressions facilitating easy software or hardware implementations of the algorithms. Comparisons between the proposed algorithms and the existing 3-D radix-(2/spl times/2/spl times/2) FFT algorithm are carried out showing that significant savings in terms of the number of arithmetic operations, data transfers, and twiddle factor evaluations or accesses to the lookup table can be achieved using the radix-(2/spl times/2/spl times/2)/(4/spl times/4/spl times/4) DIF FFT algorithm over the radix-(2/spl times/2/spl times/2) FFT algorithm. It is also established that further savings can be achieved by using the radix-(2/spl times/2/spl times/2)/(8/spl times/8/spl times/8) DIF FFT algorithm.

关键词： signal processing algorithms Discrete Fourier transforms Fast Fourier transforms Arithmetic Software algorithms Polynomials Multidimensional systems Closed-form solution Hardware Table lookup

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Predistorter design employing parallel piecewise linear structure and inverse coordinate mapping for broadband communications

Predistorter design employing parallel piecewise linear stru...

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14th European signal processing Conference, EUSIPCO 2006

作者： Cheong, Mei Yen Werner, Stefan Laakso, Timo I. Cousseau, Juan Figueroa, Jose L. Signal Processing Laboratory Center of Excellence Helsinki University of Technology Finland CONICET Department of Electrical Engineering and Computer Science Universidad Nacional Del sur Bahía Blanca Argentina

This paper proposes a low-complexity predistorter (PD) for compensation of both the AM/AM and the AM/PM conversions with memory. The nonlinear power amplifier (PA) is modeled as a Wiener type nonlinearity. The quasi-static nonlinearities are modeled using a class of piecewise linear (PWL) functions. The PWL function facilitates an efficient PD identification algorithm. The proposed algorithm involves a novel inverse coordinate mapping (ICM) method that maps the nonlinear characteristics of the PA to that of the PD, and parameter estimations that do not require matrix inversion. The indirect learning architecture is used to provide an on-line compensation of thememory effect of the PA. Simulation results show that the PD that compensates also the AM/PM distortion performs significantly better than one that considers only the AM/AM nonlinearity. The proposed PD is also shown to outperform the orthogonal polynomial PD in both adjacent channel interference suppression and inband distortion compensation.

关键词： Power amplifiers

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