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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： Chao-Cheng Wu Chein-I Chang Remote Sensing Signal and Image Processing Laboratory the Department of Computer Science and Electrical Engineering Department University of Maryland Baltimore MD USA

One of commonly used criteria for finding an endmember set is to assume that for a given number of endmembers, p, a p-vertex simplex with its vertices specified by p endmembers always yields the maximum volume. Since there are also other criteria which have been widely used for endmember extraction, the issue of interest is "does an endmember set really produce a simplex with maximum volume?" In other words, using the criterion of a simplex with maximum volume is a better and more effective measure than other criteria currently being used by endmember extraction such as orthogonal projection-based pixel purity index (PPI), fully constrained least squares-based spectral unmixing, etc. This paper explores this issue by investigating a number of popular endmember extraction algorithms which are designed by different criteria. An extensive experiment-based study is also conducted for comparative analysis.

关键词： Algorithm design and analysis Least squares methods Hyperspectral imaging Indexes Volume measurement Chaos Data mining Subspace constraints Computational efficiency Current measurement

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Blind Extraction of Microsleep Events

Blind Extraction of Microsleep Events

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International Conference on Digital signal processing (DSP)

作者： Wai Yie Leong Danilo P. Mandic Martin Golz David Sommer Communications and Signal Processing Group Electronics and Electrical Engineering Imperial College London UK Department of Computer Science University of Applied Sciences Schmalkalden Schmalkalden Germany

The aim of this study is to detect the occurrence of microsleep events in an overnight driving task. We propose a biosignal analysis method for the detection and extraction of microsleep events. This is achieved by employing blind source extraction method based on a cascaded nonlinear estimator to extract the relevant microsleep events. The cascaded nonlinear estimator jointly estimates the kurtosis and measure the nonlinearity and noise effects within the biosignal. This proposed method was applied to the electroencephalogram and electroculogram recorded of 12 young volunteers while performing monotonic overnight driving in a real car driving simulation laboratory. The extracted microsleep signals can then be used for driving simulation pilot studies for alertness monitoring, and to trigger the activation of alertness countermeasures.

关键词： Brain modeling Electroencephalography Detectors Event detection State estimation Diseases Data mining Fatigue Electrooculography Magnetic heads

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Split predistortion approach for reduced complexity terminal in OFDM systems

Split predistortion approach for reduced complexity terminal...

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IEEE 65th Vehicular Technology Conference (VTC-Spring 2007), vol.6

作者： Fernando Gregorio Stefan Werner Risto Wichman Juan E. Cousseau Signal Processing Laboratory Helsinki University of Technology Finland Department of Electrical and Computer Engineering Universidad Nacional del Sur Bahia Blanca Argentina

This paper proposes a novel split predistorter structure to remove nonlinear distortion caused by nonlinear power amplifier with memory. Unlike conventional techniques, the new technique does not require an estimation of the memory model at the transmitter leading to a reduced implementation complexity. Simulations have been carried out using the SUI3 channel model developed for IEEE802.16 standard. The results verify the good performance of the proposed predistorter for several relevant power amplifier models.

关键词： Predistortion OFDM Power system modeling Nonlinear distortion Power amplifiers Wireless LAN WiMAX Transmitters Peak to average power ratio Bit error rate

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Broadband powerr amplifier distortion cancellation with model estimation inthe receiver

Broadband powerr amplifier distortion cancellation with mode...

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IEEE Workshop on signal processing Advances in Wireless communications (SPAWC)

作者： Fernando H. Gregorio Stefan Werner Juan E. Cousseau Risto Wichman Signal Processing Laboratory Helsinki University of Technology Finland Department of Electrical and Computer Engineering Universidad Nacional del Sur Bahia Blanca Argentina

This paper proposes a practical receiver cancellation technique for removing nonlinear power amplifier (PA) distortion in OFDM systems. By performing the estimation of the PA model parameters at the receiver, the implementation complexity of the transmitter can be reduced. Furthermore, a simple adaptation rule is provided to enable tracking of the PA model parameters. As a consequence, cancellation of nonlinear distortion can be achieved without assuming that the PA model is known a priori at the receiver. Simulation results show that good levels of distortion cancellation are possible for a system with a broadband PA with memory.

关键词： Broadband amplifiers Power amplifiers Nonlinear distortion OFDM Power system modeling Peak to average power ratio Radio transmitters Intersymbol interference Time-varying channels signal processing

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Beamspace Adaptive Beamforming for Broadband Planar Arrays

Beamspace Adaptive Beamforming for Broadband Planar Arrays

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International Workshop on Antenna Technology: Small Antennas and Novel Metamaterials, iWAT

作者： Wei Liu Renbiao Wu Richard Langley Communications Research Group Department of Electronic & Electrical Engineering University of Sheffield UK Tianjin Key Laboratory for Advanced Signal Processing Civil Aviation University of China China

A beamspace adaptive planar array for broadband beamforming based on the frequency invariant beamforming technique is proposed. The relationship between the dimension of the two-dimensional (2-D) prototype filter for the beam design and the number of independent beams is discussed and an arrangement of the desired frequency invariant responses for beamspace processing is provided, which guarantees the linear independence of the beams. Simulation results show the effectiveness of the method with increased convergence speed and a resultant frequency invariant beam pattern

关键词： Array signal processing Planar arrays Frequency Finite impulse response filter Convergence Discrete Fourier transforms Two dimensional displays Prototypes Sensor systems Computational complexity

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Fast-fading channel estimator using DCT and simplified kalman filter

Fast-fading channel estimator using DCT and simplified kalma...

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IEEE Workshop on signal processing Advances in Wireless communications (SPAWC)

作者： J. F. Schmidt J. E. Cousseau R. Wichman F. H. Gregorio CONICET-Department of Electrical and Computer Engineering Universidad Nacional del Sur Bahia Blanca Argentina Signal Processing Laboratory Hut Helsinki University of Technology Finland

We present a novel channel estimator for fading channels using basis function approximations and Kalman filtering. The proposal results in a low complexity estimator that is robust to the shape of the channel Doppler spectrum and allows different Doppler spectra for each channel coefficient in a frequency-selective scenario. The estimator is based on the description of channel variations via truncated discrete cosine transform (DCT). We show that DCT can be approximated by a set of linear narrow-band passband filters that can be inserted into a Kalman filter formulation that track a set of decoupled parameters. This estimator attains close to perfect channel knowledge performance with only 1% training symbols in a data frame with Doppler frequencies up to 0.8 times the frame frequency.

关键词： Discrete cosine transforms Frequency estimation Function approximation Fading Kalman filters Filtering Proposals Robustness Shape Narrowband

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CHESAPEAKE BAY WATER QUALITY MONITORING USING SATELLITE IMAGERY

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International Journal of High Speed Electronics and Systems 2007年第4期17卷 681-688页

作者： BHARATH RAMAKRISHNA CHEIN-I CHANG BRUCE TROU JERRY HENQEMIHLE Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD 21250 USA Microtel LLC 111 Centerway Greenbelt MD 20770 USA

The Chesapeake Bay is a valued ecological, economic, recreational, cultural and scenic resource. The Bay watershed States and the District of Columbia, in conjunction with the EPA Chesapeake Bay Program, have worked and teamed together over the past 20 years to protect and restore the Bay ecosystem. A key component of this effort is water quality and habitat monitoring to assess the impact of management actions and natural processes, and evaluate habitat parameters on living resources such as submerged aquatic vegetation (SAV), oysters, and fisheries. Using aerial and satellite remote sensing imagery has become a practical and effective means of monitoring water quality in a timely manner. Of particular interest in evaluation of water clarity are several initiative measures. Specifically, Secchi-Disk Transparency (SDT) and Chlorophyll a (Chl- a ) have been widely accepted as critical indicators of water quality and their reliable estimation using satellite imagery provides a cost effective and speedy means for water quality monitoring. Work done at Water Resources Center, University of Minnesota has demonstrated the feasibility of performing regional assessment of lake water quality using LANDSAT image data. This paper investigates an approach similar to their work but uses a different type of satellite imagery, EO-1 ALI imagery where the SDT and Chl- a are also used as indicators to estimate water quality for the Chesapeake Bay and DC area (Potomac River). In doing so, three major issues are investigated, which are (1) the study site that is an open Bay area, not a self-contained lake; (2) investigation of applicability of equations that are used to specify the SDT and Chl- a to our Bay area study; (3) the use of a different type of satellite imagery for water quality monitoring. This paper develops techniques to address these three issues and presents preliminary experiments which show encouraging results.

关键词： Chesapeake Bay EO-1 ALI Imagery Secchi Depth (SDT) Chl- a

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Low SNR Capacity of Fading Channels -MIMO and Delay Spread

Low SNR Capacity of Fading Channels -MIMO and Delay Spread

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IEEE International Symposium on Information Theory

作者： Vignesh Sethuraman Ligong Wang Bruce Hajek Amos Lapidoth Qualcomm Inc. Campbell CA USA ETH Zurich Signal and Information Processing Laboratory Switzerland Department of Electrical and Computer Engineering and the Coordinated Science Laboratory University of Illinois Urbana-Champaign USA

ISBN: (纸本)9781424413973

Discrete-time Rayleigh fading multiple-input multiple-output (MIMO) channels are considered, with no channel state information at the transmitter and receiver. The fading is assumed to be correlated in time and independent from antenna to antenna. Peak and average transmit power constraints are imposed, either on the sum over antennas, or on each individual antenna. In both cases, an upper bound and an asymptotic lower bound, as the signal-to-noise ratio approaches zero, on the channel capacity are presented. The limit of normalized capacity is identified under the sum power constraints, and, for a subclass of channels, for individual power constraints. These results carry over to a SISO channel with delay spread (i.e. frequency selective fading).

关键词： Channel capacity Fading Delay Rayleigh channels MIMO Transmitting antennas Channel state information Transmitters Upper bound signal to noise ratio

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Ensemble Based Data Fusion from Parietal Region Event Related Potentials for Early Diagnosis of Alzheimer's Disease

Ensemble Based Data Fusion from Parietal Region Event Relate...

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International Joint Conference on Neural Networks (IJCNN)

作者： Brian A. Balut Matthew T. Karnick Deborah Green John Kounios Christopher M. Clark Robi Polikar Signal Processing and Pattern Recognition Laboratory of the Electrical and Computer Engineering Department Rowan University Glassboro NJ USA Department of Psychology Drexel University Philadelphia PA USA Department of Neurology University of Pennsylvania Philadelphia PA USA

As a natural consequence of steady increase of average population age in developed countries, Alzheimer's disease is becoming an increasingly important public health concern. The financial and emotional toll of the disease is exacerbated with lack of standard diagnostic procedures available at the community clinics and hospitals, where most patients are evaluated. In our recent preliminary results, we have reported that the event related potentials (ERPs) of the electroencephalogram can be used to train an ensemble-based classifier for automated diagnosis of Alzheimer's disease. In this study, we present an updated alternative approach by combining complementary information provided by ERPs obtained from several parietal region electrodes. The results indicate that ERPs obtained from parietal region of the cortex carry substantial complementary diagnostic information. Specifically, the diagnostic ability of such an approach is substantially better, compared to the performance obtained by using data from any of the individual electrodes alone. Furthermore, the diagnostic performance of the proposed approach compares very favorably to that obtained at community clinics and hospitals.

关键词： Alzheimer's disease Enterprise resource planning Hospitals Electrodes Senior citizens Biomarkers Protocols Delay Neural networks USA Councils

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An ARMA System Identification Scheme in the Presence of Noise

An ARMA System Identification Scheme in the Presence of Nois...

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

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

This paper presents a scheme for the identification of minimum-phase autoregressive moving average (ARMA) systems in the presence of noise. For the identification of the AR part, we propose to repeat the correlation operation on an enhanced autocorrelation function of the observed signal based on a decision criterion and then employ the resultant to an extended form of Yule-Walker equations. A frequency domain noise-compensation scheme is introduced which operates on the noise-contaminated residual signal. The MA parameters are then estimated via the spectral factorization performed on the power spectrum of the noise-compensated residual signal. computer simulations exhibit a superior estimation performance even at low levels of signal-to-noise ratio (SNR).

关键词： System identification Working environment noise signal processing Equations Frequency domain analysis Parameter estimation Autocorrelation signal to noise ratio Noise reduction signal processing algorithms

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