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Reliability of individual differences in lipreading

The Journal of the Acoustical Society of America 2005年第S1期82卷 S24-S24页

作者： Marilyn E. Demorest Lynne E. Bernstein Silvio P. Eberhardt Department of Psychology University of Maryland Baltimore County Catonsville MD 21228 Speech Processing Laboratory Department of Electrical and Computer Engineering Johns Hopkins University Baltimore MD 21218

Evaluation of the benefits of sensory aids requires stimulus materials whose psychometric characteristics are known. Generalizability theory was applied to data from two experiments to estimate measurement error arising from different materials, different talkers, and practice. Stimulus materials consisted of CID sentences and CV nonsense syllables produced by a male and a female talker and stored on video laserdisk. In experiment I, 104 normal‐hearing subjects lipread the CID sentences in a single test session. Results indicate that there are substantial individual differences in lipreading performance among subjects, but that there are also systematic differences among sentences and among talkers that must be taken into account in interpreting test performance. In experiment II, 15 normal‐hearing subjects who participated in an intensive training protocol involving vibrotactile supplements to lipreading were given pre‐ and posttests on the CID sentences and on the CV syllables. Individual differences in performance on sentences were highly stable over the training period, suggesting relatively uniform improvements due to training. Reliability over time was lower for the CV syllables and correlations between the CV and sentence materials were weak both at the pretest and posttest. [Work supported by NIH.]

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Corrections to “Stability of Multidimensional Systems Using Genetic Algorithms”

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IEEE Transactions on Circuits and Systems I: Regular Papers 2005年第9期52卷 1982-1982页

作者： N.E. Mastorakis I.F. Gonos M.N.S. Swamy Department of Computer Science Military Institution Hellenic Naval Academy University Education Piraeus Greece High Voltage Laboratory School of Electrical and Computer Engineering National and Technical University of Athens Athens Greece Center for Signal Processing and Communications Department of Electrical and Computer Engineering Concordia University Montreal QUE Canada

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Spatial matched processing for multipath propagation

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The Journal of the Acoustical Society of America 2005年第S1期82卷 S73-S73页

作者： Matthew Dzieciuch T. G. Birdsall Communication and Signal Processing Laboratory 4242 EECS Building The University of Michigan Ann Arbor MI 48104 Department of Electrical Engineering and Computer Science The University of Michigan Ann Arbor MI 48104

Underwater acoustic propagation is characterized by multipath or multimode propagation. Ray theory and mode theory are not fully adequate for modeling physical reality. Impulse responses can be more accurately calculated using Gaussian beam theory. signal processors can be designed to take advantage of the channel complexity if the propagation is actually known so that detectability is increased. The proposed technique, channel matched filtering, synthetically backpropagates the wave front to a hypothesized source location. Accurate passive estimates of source location can be made without knowledge of the signal characteristics. GB theory can easily accommodate a range‐dependent deep water environment. [This research supported by the Office of Naval Research.]

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A new application of texture unit coding to mass classification for mammograms

A new application of texture unit coding to mass classificat...

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2004 International Conference on Image processing, ICIP 2004

作者： Chen, Yuan Chang, Chein-I. Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD 21250

Texture is one of important features of masses in mammograms. A recent texture unit-based texture spectrum approach, referred to as Texture Unit Coding (TUC) has shown promise in texture classification. This paper presents a new application of the TUC to mass classification in mammograms. The TUC generates a texture spectrum for a texture image that can be used to describe the characteristics of masses. It also develops an information divergence (ID)-based discrimination criterion to measure the discrepancy between two texture spectra, a concept yet to explore in texture analysis. The TUC along with ID are further applied to mass classification in mammograms where the MiniMammographic Database provided by the Mammographie Image Analysis Society (MIAS) is used for experiments. ©2004 IEEE.

关键词： Mammography

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How to effectively utilize information to design hyperspectral target detection and classification algorithms

How to effectively utilize information to design hyperspectr...

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2003 IEEE Workshop on Advances in Techniques for Analysis of Remotely Sensed Data

作者： Chang, Chein-I. Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County 1000 Hilltop Circle BaltimoreMD21250 United States

ISBN: (纸本)0780383508

Hyperspectral imagery offers a means of uncovering enormous spectral information that can be used for various applications in data exploitation. How effectively such information is used affects the way image analysis algorithms are designed. In this paper, we take up this issue and focus on algorithms designed and developed for target detection and classification in hyperspectral imagery. In order to effectively characterize the information available before and after the data are processed, the a priori information and a posteriori information are used in accordance with how the information is obtained. A piece of information is referred to as a priori information if it is provided by known knowledge before data are processed. On the other hand, a piece of information is referred to as a posteriori information if it is unknown a priori, but can be obtained directly from the data in an unsupervised fashion during the course of data processing. Since a priori information is known beforehand, it can be further decomposed into two types of information, desired and undesired a priori information. The desired a priori information is the knowledge that will assist, improve and enhance data analysis, whereas the undesired a priori information is the knowledge that hinders, interferes or destructs analysis during data processing. This paper investigates how these three types of information play their roles in design and development of several hyperspectral target detection and classification algorithms. Experiments are also conducted to validate their utility. © 2004 IEEE.

关键词： Classification (of information)

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Discrimination and identification for subpixel targets in hyperspectral imagery

Discrimination and identification for subpixel targets in hy...

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2004 International Conference on Image processing, ICIP 2004

作者： Chang, Chein-I. Liu, Weimin Chang, Chein-Chi Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD 21250 Department of Civil and Environmental Engineering University of Maryland Baltimore County Baltimore MD 21250

Spectral measures have been used in material identification and discrimination. They are effective if the spectral signatures are calibrated and not contaminated. However, it may not be true in many real applications, specifically, for mixed pixels and subpixel targets. This paper investigates the issue of discrimination and identification for subpixel targets and further develops sample spectral covariance/correlation matrix-based hyperspectral measures to account for spectral variability within subpixel targets. Two types of measures are of interest and studied, Mahalanobis distance-based hyperspectral measures and matched filter-based hyperspectral measures. In order to substantiate the proposed measures, a real data-based comparative analysis is conducted and compared to two spectral similarity measures, spectral angle mapper (SAM) and spectral information divergence (SID) for performance evaluation. The experiments show that both Mahalanobis distance-based hyperspectral measures and matched filter-based hyperspectral measures work very effectively and outperformed the SAM and the SID in discrimination and identification for subpixel targets. ©2004 IEEE.

关键词： Imaging techniques

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Shared mixture GMM classifier

Shared mixture GMM classifier

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International Conference on signal processing and Communications, SPCOM

作者： A.G. Krishna T.V. Sreenivas Speech and Audio Signal Processing Laboratory Department of Electrical Communication Engineering Indian Institute of Science Bangalore India

In this paper, we propose the shared mixture GMM classifier. Mixtures of a GMM which represent areas in the feature space must have very less overlap across classes for best performance. If not, patterns of a class belonging to regions of overlap score high likelihoods with not only the mixture of its own class, but also that mixture of another class thereby making a high contribution to the likelihood score with respect to the other class model. We propose a computational method of determining if such mixtures exist and using an automatic method of determining such mixtures based on discriminability between classes, we propose choosing the mixtures for each GMM from the set of all mixtures of all GMMs. Mixtures that have significant overlap with other classes get shared between the contending classes. Weights are based on cluster-class membership matrix defined in the paper. We have compared the performance of this shared mixture GMM with a conventional GMM, for a 14 class music instrument recognition task. The new model performs competitively compared to the conventional GMM, and outperforms it when there is lesser training data.

关键词： Instruments Training data speech processing signal processing Speaker recognition Probability density function Robustness Convergence Testing Pattern classification

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On extended finite element method (XFEM) for modelling of organ deformations associated with surgical cuts

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International Symposium on Medical Simulation, ISMS 2004

作者： Vigneron, Lara M. Verly, Jacques G. Warfield, Simon K. Signal Processing Group Department of Electrical Engineering and Computer Science University of Liège Belgium Surgical Planning Laboratory Brigham and Women’s Hospital and Harvard Medical School Boston United States

ISBN: (纸本)3540221867

The Extended Finite Element Method (XFEM) is a technique used in fracture mechanics to predict how objects deform as cracks form and propagate through them. Here, we propose the use of XFEM to model the deformations resulting from cutting through organ tissues. We show that XFEM has the potential for being the technique of choice for modelling tissue retraction and resection during surgery. Candidates applications are surgical simulators and image-guided surgery. A key feature of XFEM is that material discontinuities through FEM meshes can be handled without mesh adaptation or remeshing, as would be required in regular FEM. As a preliminary illustration, we show the result of XFEM calculation for a simple 2D shape in which a linear cut was made. © Springer-Verlag Berlin Heidelberg 2004.

关键词： Finite element method

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Heart rate variability analysis of effect of nicotine using lomb- welch periodograms

Heart rate variability analysis of effect of nicotine using ...

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Conference Proceedings - 26th Annual International Conference of the IEEE engineering in Medicine and Biology Society, EMBC 2004

作者： Thong, Tran Yung, Iris O. Zajdel, Daniel P. Ellingson, Roger M. McNames, James Aboy, Mateo Oken, Barry S. Department of Biomedical Engineering Oregon Health and Science University Beaverton OR School of Medicine Oregon Health and Science University Portland OR Department of Neurology Oregon Health and Science University Portland OR Biomed. Signal Processing Laboratory Electrical and Computer Engineering Portland State University Portland OR

Heart rate variability (HRV) is frequently used to measure autonomic nervous system (ANS) activity. However, little is known about the mechanism underlying pharmacologically induced changes in HRV. Previous research has shown that nicotine exposure stimulates the ANS, mediating a wide spectrum of physiological and behavioral effects, including altered respiratory sinus arrhythmia and enhanced arousal and attention. Using Lomb-Welch periodograms, the effect of nicotine on the ANS in 14 nicotinenaive human subjects are studied. Results showed an increase in the low frequency (LF) to high frequency (HF) ratio with little change in mean heart rate. Results suggest that nicotine affects both sympathetic and parasympathetic reactivities and that the LF/HF best characterizes early ANS activated nicotine changes in HRV. The Lomb-Welch periodogram of the HRV is also compared to the conventional interpolated Welch periodogram. The attenuation of the high frequency components due to interpolation of the non-uniform R-R intervals is found to be a function of the power of the high frequency components, increasing with increasing power. Thus analyses using Welch periodograms that make use of the high frequency components may yield erroneous results.

关键词： Biomedical engineering

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Adaptive causal anomaly detection for hyperspectral imagery

Adaptive causal anomaly detection for hyperspectral imagery

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

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

ISBN: (纸本)0780387422

Anomaly detection finds target pixels whose signatures are spectrally distinct from their surrounding pixels. It is generally performed without prior knowledge. This paper presents an adaptive causal anomaly detector (ACAD) which implements a causal anomaly detector in such a fashion that a target pixel will be removed from the data correlation matrix once it is detected as an anomaly. As a result, it improves the commonly used RX algorithm as well as a recently developed causal RX filter

关键词： Hyperspectral imaging Filters Detectors Covariance matrix Adaptive signal detection Hyperspectral sensors Remote sensing signal processing Image processing Laboratories

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