检索结果-内蒙古大学图书馆

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

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

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

来源：评论

学校读者我要写书评

暂无评论

On symbol collisions in FH-OFDMA

On symbol collisions in FH-OFDMA

引用

IEEE Conference on Vehicular Technology (VTC)

作者： T. Kurt H. Delic Communications and Signal Processing Laboratory School of Information Technology and Engineering University of Ottawa ONT Canada Signal and Image Processing Laboratory Department of Electrical and Electronics Engineering Boğaziçi University Istanbul Turkey

A frequency-hopping orthogonal frequency-division multiple access (FH-OFDMA) system is considered. Each user transmits by hopping randomly from one cluster of subcarriers to the next. The subcarrier clusters may be fixed groups, or they may be formed randomly at each hopping instant. It is shown analytically that the expected number of collisions per symbol is independent of the hopping strategy. Bit error rate computations via simulations in a frequency-selective fading channel indicate that space-frequency coding reduces the expected number of symbols involved in a cluster collision when the subcarriers are hopped independently.

关键词： OFDM signal processing Radio spectrum management Interference elimination GSM Information technology Image processing Laboratories Bit error rate Computational modeling

来源：评论

学校读者我要写书评

暂无评论

Quasi-orthogonal space-time block coded transceiver systems over frequency selective wireless fading channels

Quasi-orthogonal space-time block coded transceiver systems ...

引用

International Conference on Acoustics, Speech, and signal processing (ICASSP)

作者： Lei He Hongya Ge Center for Communications and Signal Processing Research Department of Electrical and Computer Engineering New Jersey Institute of Technology Newark NJ USA

ISBN: (纸本)0780384849

We propose a new block time-reversal conjugate based quasi-orthogonal space-time block encoding and decoding (QO-STBC) scheme for a wireless system with four transmit antennas in frequency selective fading channels. The proposed scheme effectively combats channel dispersion and frequency selectivity due to multipath, yet still provides full diversity gain. We also propose a maximum likelihood (ML) solution, with a simple decoupled structure, to decode the block time-reversal conjugate QO-STBC symbols at low complexity for channels with short delay.

关键词： Transceivers Fading Finite impulse response filter Transmitters Diversity methods Frequency conversion Maximum likelihood decoding Polynomials Dispersion Time domain analysis

来源：评论

学校读者我要写书评

暂无评论

Adaptive causal anomaly detection for hyperspectral imagery

Adaptive causal anomaly detection for hyperspectral imagery

引用

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

来源：评论

学校读者我要写书评

暂无评论

Distributed Matlab based signal and image processing using JavaPorts

Distributed Matlab based signal and image processing using J...

引用

International Conference on Acoustics, Speech, and signal processing (ICASSP)

作者： E.S. Manolakos D.G. Galatopoullos A.P. Funk Communications and Digital Signal Processing Center for Research and Graduate Studies Electrical and Computer Engineering Department Northeastern University Boston MA USA

Many scientists and engineers have signal and image processing applications that involve large data sets and could benefit from parallel processing on readily-available clusters of workstations (COWs). Unfortunately these applications often exist as legacy code, such as Matlab functions, which are not easily parallelizable. The goal of the JavaPorts project is to provide a framework for flexible development of parallel and distributed component-based applications for heterogeneous COWs. The latest version of the package supports the integration of Java and Matlab components into the same application. The main features of the JavaPorts framework and its tools are discussed and application examples are presented which highlight its ability to support the rapid prototyping of parallel and distributed computing strategies with communicating Java and Matlab components.

关键词： signal processing Image processing Java Cows Data engineering Parallel processing Workstations Packaging Prototypes Distributed computing

来源：评论

学校读者我要写书评

暂无评论

AR model parameter estimation: from factor graphs to algorithms

AR model parameter estimation: from factor graphs to algorit...

引用

International Conference on Acoustics, Speech, and signal processing (ICASSP)

作者： S. Korl H.A. Loeliger A.G. Lindgren Signal and Information Processing Laboratory ETH Zurich Switzerland Department of Electrical & Computer Engineering University of Rhode Island USA

The classic problem of estimating the parameters of an auto-regressive (AR) model is considered from a graphical model viewpoint. A number of practical parameter estimation algorithms - some of them well known, others apparently new - are derived as "summary propagation" in a factor graph. In particular, we demonstrate the joint estimation of AR coefficients, innovation variance, and noise variance.

关键词： Parameter estimation signal processing algorithms Technological innovation Graphical models Gaussian noise State-space methods signal processing Information processing Laboratories Error correction codes

来源：评论

学校读者我要写书评

暂无评论

Antiderivative series for differentiable functions

引用

International Journal of Mathematical Education in Science and Technology 2004年第5期35卷 725-731页

作者： Howard, Roy M. Communications and Signal Processing Group Department of Electrical and Computer Engineering Curtin University of Technology Perth 6845 Australia

A series defining the antiderivative of an nth order differentiable function is defined. This series provides an explicit expression for the second part of the Fundamental Theorem of Calculus and can facilitate the es...

关键词：

来源：评论

学校读者我要写书评

暂无评论

Distributed signature sequence adaptation for downlink multicode MC-CDMA system

Distributed signature sequence adaptation for downlink multi...

引用

IEEE International Symposium on Spread Spectrum Techniques and Applications

作者： Jianming Zhu Y. Bar-Ness Center for Communications and Signal Processing Research Department of Electrical and Computer Engineering New Jersey Institute of Technology University Heights Newark NJ USA

A distributed signature sequence adaptation scheme is considered for the downlink of a MC-CDMA system, wherein each mobile user selfishly adapts its signature sequences to improve its own performance using measurements at its location with no consideration to the performance of other users in the system. The convergence of such an adaptation scheme is shown using a game theory framework. That is, with any initial signature sequences in the system, the proposed adaptation scheme definitely converges to a set of signature sequences at which no user can further improve its own performance with individual adaptation.

关键词： Downlink Multicarrier code division multiple access Iterative algorithms Game theory Wireless communication System performance Multiple access interference Base stations Channel state information Distributed algorithms

来源：评论

学校读者我要写书评

暂无评论

A nested spatial window-based approach to target detection for hyperspectral imagery

A nested spatial window-based approach to target detection f...

引用

IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

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

ISBN: (纸本)0780387422

A great challenge of hyperspectral target detection is to detect subtle targets without prior knowledge, particularly, when the targets of interest are insignificant and occur with low probabilities. This work provides a promising alternative to adaptive hyperspectral target detection. It considers a nested spatial window-based target detection (NSWTD) approach for hyperspectral imagery where a set of different spatial windows are nested and implemented to extract targets whose signatures are spectrally and spatially distinct. The use of nested spatial windows is determined by the image pixel resolution and applications. In order to demonstrate the performance of the proposed NSWTD approach, dual nested windows and three nested windows are implemented for computer simulations and real hyperspectral image experiments. The experimental results demonstrate that our proposed NSWTD approach performs effectively and improves a recent adaptive anomaly detector developed by Kwon et al. and the commonly used anomaly detector developed by Reed and Yu, referred to as RX algorithm. Its computation complexity is also very simple.

关键词： Object detection Hyperspectral imaging Hyperspectral sensors Detectors Spatial resolution Remote sensing signal processing Image processing Laboratories computer science

来源：评论

学校读者我要写书评

暂无评论

Power spectral density estimation and tracking of nonstationary pressure signals based on Kalman filtering

Power spectral density estimation and tracking of nonstation...

引用

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

作者： Aboy, M. McNames, J. Márquez, Óscar W. Hornero, R. Thong, T. Goldstein, B. Biomed. Signal Processing Laboratory Electrical and Computer Engineering Portland State University Portland United States Signal Theory Dept. ETSI-Telecomunicación University of Vigo Spain Signal Theory Dept. ETSI-Telecomunicación University of Valladolid Spain Biomedical Engineering Department Oregon Health and Science University Portland United States Pediatrics Department Oregon Health and Science University Portland United States

We describe an algorithm to estimate and track slow changes in power spectral density (PSD) of nonstationary pressure signals. The algorithm is based on a Kalman filter that adaptively generates an estimate of the autoregressive model parameters at each time instant. The algorithm exhibits superior PSD tracking performance in nonstationary pressure signals than classical nonparametric methodologies, and does not assume a piecewise stationary model of the data. Furthermore, it provides better time-frequency resolution, and is robust to model mismatches. We demonstrate its usefulness by a sample application involving PSD estimation and tracking of short records of simulated pressure waveforms. This algorithm is intended for applications were the PSD must be estimated and tacked during short transient periods, possibly after clinical interventions.

关键词： signal processing

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：