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Student Conference on Research and Development (SCOReD)

作者： Z.M. Zin S.H. Salleh S. Daliman M.D. Sulaiman Digital Signal Processing Laboratory Department of Microelectronics and Computer Engineering Faculty of Electrical Engineering Universiti Teknologi Malaysia Skudai Malaysia Cardiology Unit Department of Medicine Faculty of Medicine Universiti Kebangsaan Malaysia Kuala Lumpur Malaysia

This paper presents the application of wavelet transform analysis method to the heart sounds signal. The heart sounds is a non-stationery signal, thus it is very important to study the frequency and time information. One of the time-frequency analysis methods is short time Fourier transforms. However, the STFT analysis is limited by the time and frequency resolution. The wavelet transform was introduced to curb the resolution problem in STFT. The wavelet transform is a multi-resolution time-scale analysis that gives high resolution for low frequency components and low resolution for high frequency components. Since majority of heart sounds component lies in low frequency, thus the application of wavelet transform to heart sounds is very suitable. Results in time-frequency representation clearly show that the wavelet transform is capable to distinguish between the normal with a few types of abnormal heart sounds. The murmurs caused by particular heart diseases such as aortic regurgitation, aortic stenosis, mitral regurgitation, mitral stenosis, pulmonary regurgitation and tricuspid regurgitation were clearly shown under continuous wavelet representation.

关键词： Continuous wavelet transforms Heart Wavelet analysis Wavelet transforms signal resolution signal analysis Fourier transforms Time frequency analysis Cardiac disease Stethoscope

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Accuracy of ultra-short heart rate variability measures

Accuracy of ultra-short heart rate variability measures

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

作者： T. Thong K. Li J. McNames M. Aboy B. Goldstein Department of Biomedical Engineering OGI School of Science & Engineering Oregon Health and Sciences University Beaverton OR USA Biomedical Signal Processing Laboratory Department of Electrical & Computer Engineering Portland State University Portland OR USA Department of Pediatrics Oregon Health and Sciences University Portland OR USA

Heart rate variability (HRV) measures have been used to assess autonomic cardiac regulation. The standard lengths used in HRV analyses are 5 minutes and 24 hours. In this paper we investigated the accuracy of three HRV measures for ultra-short record length, 10 seconds, which is the length of standard electrocardiograms. The measures chosen were: Standard Deviation Normal-Normal (SDNN), Root Mean Square of Successive Differences (RMSSD), frequency of the peak of the high-frequency (HF) spectra derived using a non-parametric spectrum method. Our analyses indicated that the RMSSD(10)s would be consistent estimates of the 5 minute RMSSD(300)s. The SDNN(10)s were found not to be accurate in our analyses. The HF peak, while promising, would require further studies.

关键词： Heart rate variability Neural networks Measurement standards Time measurement Biomedical measurements Electrocardiography Histograms Biomedical engineering Laboratories Root mean square

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Paroxysmal atrial fibrillation prediction using isolated premature atrial events and paroxysmal atrial tachycardia

Paroxysmal atrial fibrillation prediction using isolated pre...

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

作者： T. Thong J. McNames M. Aboy B. Goldstein Department of Biomedical Engineering OGI School of Science & Engineering Oregon Health and Sciences University Beaverton OR USA Biomedical Signal Processing Laboratory Department of Electrical & Computer Engineering Portland State University Portland OR USA Department of Pediatrics Oregon Health and Sciences University Portland OR USA

A simplified predictor of episodes of paroxysmal atrial fibrillation (PAF) is presented. Over a thirty minute monitoring time, the number of premature atrial complexes (PAC) without normal sinus node reset is counted. When the number of such PACs changes by more than 2 over the monitoring period, a PAF prediction is made. The PAC test is supplemented with a paroxysmal atrial tachycardia (PAT) test that uses a similar approach in identifying and counting episodes of PAF. The combined PAC and PAT test yields a sensitivity of 68%, a specificity of 86% and a positive predictivity of 86% on the public test PAF database from the 2001 computer in Cardiology.

关键词： Atrial fibrillation Databases Testing Biomedical engineering Cardiology Batteries computerized monitoring Medical treatment Rhythm Electrocardiography

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Biosignal laboratory: a software tool for biomedical signal processing and analysis

Biosignal laboratory: a software tool for biomedical signal ...

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

作者： D. Cuesta P. Mico M. Aboy D. Novak R. Brezny L. Samblas D. Pastor S. Sancho Department of Computer Science Polytechnic University of Valencia Alcoy Spain Biomedical Signal Processing Laboratory Electrical and Computer Engineering Portland State University Portland OR USA Department of Cybernetics Technical University of Prague Prague Czech Republic Department of Neurology The Motol University Hospital Prague Czech Republic

Biosignal processing and analysis is a field of great importance in current medical practice. In recent years, biomedical engineers have developed many algorithms and processing techniques in order to help doctors in the examination of many different biosignals, and to find new information embedded in them and not easily observable in the raw data. Since the number and variety of these techniques grows every day, it is becoming more and more difficult to be up to date in biosignal processing. Other aspects such as signals format, algorithms implementation and comparison, artifacts, etc, make the learning process in this field longer and longer, and in many occasions a lot of different software tools are needed to visualize or process biosignals. In this paper we present a program that consists of many of the current typical biosignal processing algorithms: filtering, domain transforms, basic operators, wave detection, and unlike other similar applications, it includes a pattern recognition block. The program can also be used just to exchange signals formats. The objective of this program is to become a usual tool both for medical practice and for biomedical educational purposes.

关键词： Laboratories Software tools Biomedical signal processing signal analysis signal processing algorithms Biomedical engineering Data engineering signal processing Software algorithms Visualization

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Support vector machine classifications for microarray expression data set

Support vector machine classifications for microarray expres...

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International Conference on Computational Intelligence and Multimedia Applications

作者： Junying Zhang R. Lee Y.J. Wang Department of Electrical Engineering & Computer Science Catholic University of America Washington D.C. DC USA National Key Laboratory of Radar Signal Processing Xidian University Xi'an China Lombardi Cancer Center George town University Washington D.C. DC USA

ISBN: (纸本)0769519571

Gene selection, cancer classification and functional gene classification are three main concerns and interests by biologists for cancer detection, cancer classification, and understanding the functions of genes from the molecular level of tissues, where the large number of genes and relatively small number of experiments in gene expression data generate a great challenge. After a brief introduction of support vector machine(SVM) for classification, this paper presents recent SVM approaches for gene selection, cancer classification and functional gene classification followed by analysis on the advantages and limitations of SVM on these applications.

关键词： Support vector machines Support vector machine classification Kernel Gene expression signal processing algorithms Cancer detection Cloning Radar signal processing computer science Biology

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Significance of intracranial pressure pulse morphology in pediatric traumatc brain injury

Significance of intracranial pressure pulse morphology in pe...

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

作者： M. Aboy J. McNames D. Cuesta-Frau W. Wakeland T. Thong S. Lai B. Goldstein Biomedical Signal Processing Laboratory Electrical and Computer Engineering Portland State University Portland OR USA Computer Vision Group ETS-Alcoi Polytechnic University of Valencia Spain Systems Science Ph.D. Program Portland State University Portland OR USA Biomedical Engineering OGI School of Science and Engineering Oregon Health and Sciences University Portland OR USA Complex Systems Laboratory Department of Pediatrics Oregon Health and Sciences University Portland OR USA

We investigated the relationship between the intracranial pulse pressure (ICP/sub PP/) and the mean intracranial pressure (ICP/sub M/). In adult patients, several research groups have described a linear relationship between ICP/sub PP/ and ICP/sub M/ within the range of cerebral autoregulation. Current monitoring and therapy are mainly based on the mean ICP/sub M/, since it is believed that the ICP/sub M/ contains most of the information provided by the other pulse morphology metrics. In this paper we attempt to answer whether there is further information within the ICP morphology not explained by ICP/sub M/ that might be of prognostic significance. We screened ICP records of 42 patients admitted to the Pediatric Intensive Care Unit at Doernbecher Children's Hospital for segments in which the ICP/sub M/ varied at least 5 mmHg during a 1-hour period. We found 54 segments in 9 different pediatric TBI patients (ages 0.2-17.8 years, mean=9.9 years). ICP/sub PP/ and ICP/sub M/ were calculated for each pulse using an automatic pressure detection algorithm. The coefficient of linear correlation r was > 0.70 in 43/54 segments (p < 0.001), which indicates that there exists a linear relationship between ICP/sub PP/ and ICP/sub M/. However, we found r > 0.90 only in 16/54 segments (p=NS) . This result and visual inspection of ICP/sub PP/ vs. ICP/sub M/ density plots suggest that ICP pulse pressure is not fully explained by the ICP M.

关键词： Cranial pressure Morphology Brain injuries Iterative closest point algorithm Pediatrics Patient monitoring Medical treatment Hospitals Detection algorithms Inspection

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DOA estimation utilizing directive elements on a conformal surface

DOA estimation utilizing directive elements on a conformal s...

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IEEE National Conference on Radar

作者： K. Kim T.K. Sarkar M.C. Wicks R.F. Recio M.S. Palma Department of Electrical Engineering and Computer science Syracuse University Syracuse NY USA Sensors Directorate Signal Processing Branch Rome Site Air Force Research Laboratory Rome NY USA Grupo de Microondas y Radar Departmento Senales Sistemas y Radiocomunicaciones ETSI Telecomunicacion Universidad Politecnica de Madrid Madrid Spain

In this paper we present a methodology on how to use directive elements in an adaptive array methodology. Typically one uses isotropic elements having practically no gain then the signal level is increased by putting hundreds and thousands of these elements together. In this paper we demonstrate a methodology where the elements can be arbitrarily spaced and may even be non-planar. In addition it is shown how to deal with nonuniformly spaced and non-planar arrays. We illustrate these principles in a direction of arrival (DOA) estimation utilizing directive elements.

关键词： Direction of arrival estimation Microstrip antenna arrays Phased arrays Aircraft signal processing Directive antennas Radar signal processing Microstrip antennas Patch antennas Resonance

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GEOAIDA applied to SPOT satellite image interpretation

GEOAIDA applied to SPOT satellite image interpretation

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GRSS/ISPRS Joint Workshop on Remote Sensing and Data Fusion over Urban Areas

作者： S. Muller R.Q. Feitosa G.L. Abelha Mota D.P. da Costa V.V. da Silva K. Tanisaki Institute of Communication Theory and Signal Processing University of Hanover Hanover Germany Department of Electrical Engineering Catholic University of Rio de Janeiro Rio de Janeiro Brasil Department of Computer Engineering State University of Rio de Janeiro Rio de Janeiro Brasil Applied Geology Department State University of Rio de Janeiro Rio de Janeiro Brasil Radioecology and Global Change Laboratory and Researcher of Geomatic Program State University of Rio de Janeiro Rio de Janeiro Brasil

This paper investigates the application of a knowledge-based approach, founded on semantic networks, to the automatic land use mapping assisted by low resolution satellite images. Like the visual photo-interpretation, the automatic image interpretation considers scene and sensors knowledge, delivered by an expert photo-interpreter, as well as additional information about the region like the digital elevation model, the position of the emergent rocks, the mapping of the water bodies and the road-network. By this means, the analysis of a scene can be automatically performed, mimicking the reasoning of the photo-interpreter. The implementation of such proposal employed the GEOAIDA [J. Buckner et al., June 2001] system, a flexible environment for image interpretation developed at the University of Hanover, which exploits semantic networks to structure the domain specific knowledge. In the reported experiments, a multispectral SPOT 3 XS image was analysed resulting were evaluated and compared with a manually made reference map of the investigated scene. The automatically obtained results were evaluated and compared with a manually made reference map of the investigated scene. The experimental results demonstrate the potential of a knowledge-based approach for low resolution satellite images interpretation.

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A 1.2 V rail-to-rail differential mode input linear CMOS transconductor

A 1.2 V rail-to-rail differential mode input linear CMOS tra...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： Aimin Xu M.F. Li Signal Processing and VLSI Design Laboratory Department of Electrical and Computer Engineering National University of Singapore Singapore

Rail-to-rail differential mode input capability in low voltage CMOS transconductor design is implemented by a pull-down and a pull-up follower in an input buffer. By generating three intermediate voltages in the buffer stage, three voltages are converted to three currents and subsequently summed using MOSFETs operating in the triode region. The nonlinear current components can be cancelled completely. The lowest supply voltage V/sub dd/ is constrained by 2V/sub th/ of the MOS transistors. A single 1.2V operational transconductor amplifier (OTA) was designed using 0.35/spl mu/m CMOS technology and the simulated I-V linearity error is less than 1% within the rail-to-rail differential input range. The achieved THD is less than 0.6% for a 1 KHz, 1.2 V/sub pp/ input signal.

关键词： Rail to rail inputs Transconductors MOSFETs CMOS technology Low voltage Differential amplifiers Operational amplifiers Rail to rail amplifiers Linearity Rail to rail operation

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CHEAP CONTROL PERFORMANCE LIMITATIONS OF INPUT CONSTRAINED LINEAR SYSTEMS

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IFAC Proceedings Volumes 2002年第1期35卷 503-508页

作者： Tristan Pérez Graham C. Goodwin Maria M. Serón Department of Electrical and Computer Engineering The University of Newcastle Australia Laboratory for Dynamical Systems and Signal Processing (LSD) Universidad Nacional de Rosario Argentina

Limited authority of actuators implies that real control signals are always constrained, and in almost all cases, this produces a degradation in the performance of the system. It is thus of practical importance to understand the fundamental aspects of this performance degradation. In this paper, we take an initial step by proposing a way to characterize the performance limitations that arise in closed-loop stable linear systems due to the constraints on the magnitude of the control signal. Specifically, we evaluate the cost associated with the constraints via the L 2 norm of the tracking error of a constrained limiting optimal compensator.

关键词： Performance limitations cheap control constrained control systems

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