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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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A discriminant approach to sports video classification

A discriminant approach to sports video classification

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2007 International Symposium on Communications and Information Technologies (ISCIT 2007), vol.2

作者： N. Watcharapinchai S. Aramvith S. Siddhichai S. Marukatat Digital Signal Procession Research Laboratory Department of Electrical Engineering Faculty of Engineering Chulalongkom University Bangkok Thailand National Electronics and Computer Technology Center Pathum Thani Thailand

The problem of automating sports video classification is investigated by analyzing the low-level visual signal patterns using autocorrelogram. In this paper, two discriminant techniques are tested, namely, neural network with PCA and support vector machine (SVM), when testing data set is larger size than training data set. Seven different kinds of popularly televised sports are studied, namely basketball, Thai boxing, football, golf, diving, tennis, and volleyball. The experiments were emphasized on classifying video sequences at frame level. Classification results indicated that SVM were more efficient supervised learners than neural network with PCA for classifying sports videos with the classification accuracy of up to 91.09%.

关键词： Information technology

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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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Invariant SPHARM Shape Descriptors for Complex Geometry in MR Region of Interest Analysis

Invariant SPHARM Shape Descriptors for Complex Geometry in M...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： Ashish Uthama Rafeef Abugharbieh Anthony Traboulsee Martin J. McKeown Biomedical Signal and Image Computing Laboratory Department of Electrical and Computer Engineering University of British Columbia Vancouver Canada Department of Medicine Neurology University of British Columbia Vancouver Canada

In earlier work, we have shown the importance of including 3D shape characteristics when analyzing regions of interest (ROIs) in magnetic resonance imaging (MRI) data. Spherical harmonics (SPHARM) based ROI shape descriptors were proposed and shown to provide important complementary information to traditionally used simple volumetric ROI measures. In this paper we extend our SPHARM shape parameterization technique by using functions defined on concentric spherical shells. We then propose the use of a novel radial transform to obtain unique features even under independent rotations of the constituting shells. These enhanced features enable the analysis of 3D ROIs with complex topologies including those with possible disconnections (e.g. ventricles). We validate the proposed 3D shape descriptors on synthetic data and demonstrate their sensitivity to subtle shape changes in the presence of inter-subject variability. We also apply our approach to real MRI data and detect significant shape changes in the left and right thalamus in Parkinson's disease (PD) patients when compared against normal volunteers, complementing the observed volumetric changes.

关键词： Geometry Magnetic resonance imaging Topology Shape measurement Brain Parkinson's disease Image analysis Magnetic analysis Volume measurement Anatomy

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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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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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Multichannel Parametric Detectors for Airborne Radar Applications

Multichannel Parametric Detectors for Airborne Radar Applica...

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2007 International Waveform Diversity & Design Conference

作者： Kwang June Sohn Hongbin Li Braham Himed Joshua S. Markow Department of Electrical and Computer Engineering Stevens Institute of Technology Hoboken NJ USA Signal Laboratories Inc. Reston VA USA Air Force Research Laboratory Rome NY USA

ISBN: (纸本)9781424412754;1424412757;1424412765

We consider the problem of detecting a multichannel signal in the presence of spatially and temporally colored disturbances. The parametric Rao and GLRT detectors, recently developed by exploiting a multichannel autoregressive (AR) model for the disturbance, have been shown to perform well with limited or even no range training data. The performance of the parametric detectors, however, has been evaluated through the limited computer simulations. The disturbances were generated to follow the exact multichannel AR processes and independently from each other with the same distribution whereas the disturbances in an airborne radar environment do not follow the exact multichannel AR model. In this paper, we evaluate the detection performance of the parametric Rao and GLRT detectors using airborne data obtained from the Multi-Channel Airborne Radar Measurement (MCARM) database. This data contain typical clutter found in airborne radar systems, and cover a variety of scenarios including dense-target or heterogeneous environment. Numerical results show that the parametric Rao and GLRT detectors work well with limited or even no range training data in an airborne radar environment.

关键词： airborne radar detector Parametric Radar systems computer Simulation disturbances

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