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Performance of a self-paced brain computer interface on data contaminated with eye-movement artifacts and on data recorded in a subsequent session

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Computational Intelligence and Neuroscience 2008年第unknown期2008卷 1-13页

作者： Fatourechi, Mehrdad Ward, Rabab K. Birch, Gary E. Image and Signal Processing Laboratory Department of Electrical and Computer Engineering University of British Columbia Vancouver BC V6T 1Z4 Canada Institute for Computing Information and Cognitive Systems University of British Columbia Vancouver BC V6T 1Z4 Canada Neil Squire Society Burnaby BC V5M 3Z3 Canada

The performance of a specific self-paced BCI (SBCI) is investigated using two different datasets to determine its suitability for using online: (1) data contaminated with large-amplitude eye movements, and (2) data recorded in a session subsequent to the original sessions used to design the system. No part of the data was rejected in the subsequent session. Therefore, this dataset can be regarded as a pseudo-online test set. The SBCI under investigation uses features extracted from three specific neurological phenomena. Each of these neurological phenomena belongs to a different frequency band. Since many prominent artifacts are either of mostly low-frequency (e.g., eye movements) or mostly high-frequency nature (e.g., muscle movements), it is expected that the system shows a fairly robust performance over artifact-contaminated data. Analysis of the data of four participants using epochs contaminated with large-amplitude eye-movement artifacts shows that the system's performance deteriorates only slightly. Furthermore, the system's performance during the session subsequent to the original sessions remained largely the same as in the original sessions for three out of the four participants. This moderate drop in performance can be considered tolerable, since allowing artifact-contaminated data to be used as inputs makes the system available for users at ALL times.

关键词： .Brain computer Data Contaminated Eye-Movement Artifacts Subsequent Session Recorded in Subsequent SBCI contaminated with large-amplitude neurological phenomena

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Comparing the effect of carrier frequency offset on OFDM and single-carrier block transmission in AWGN channels

Comparing the effect of carrier frequency offset on OFDM and...

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IEEE GLOBECOM 2006 - 2006 Global Telecommunications Conference

作者： Pan, Liu Bar-Ness, Yeheskel Center for Wireless Communications and Signal Processing Research Department of Electrical and Computer Engineering New Jersey Institute of Technology Newark NJ 07102

ISBN: (纸本)142440357X

Both OFDM and single-carrier block transmission (SCBT) are promising candidates for the future high date rate communication, which well handle the frequency selective channels with a low implementation complexity. However, the sensitivity to carrier frequency offset, caused by Doppler effect or the carrier frequency difference between transmitter and receiver, is always a major concern of these block transmission systems. Actually, a controversy in comparing the carrier frequency offset effect on OFDM and SCBT systems has already been witnessed in the literature for a long time. In this paper, we first analyze the effects of carrier frequency offset on these two systems, then by carefully investigating existing works, we classify the problem into two categories: carrier frequency offset analysis with compensation and without compensation. Finally, we draw conclusions based on theoretical and numerical results that the BER performance of OFDM systems is more sensitive to carrier frequency offset than SCBT systems for the BPSK modulation in AWGN channels, although the difference of the BER performance between two systems is much smaller than theoretically predicted in previous works, if a fair comparison environment is used. Moreover, this small performance gap vanishes in higher level constellation like QPSK. © 2006 IEEE.

关键词： Carrier communication

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A Journey from signal processing to surveillance

A Journey from signal processing to surveillance

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2007 IEEE Conference on Advanced Video and signal Based Surveillance, AVSS 2007

作者： Chen, Tsuhan Advanced Multimedia Processing Laboratory Dept. of Electrical Computer Engineering Carnegie Mellon University Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA United States IEEE Signal Processing Society

ISBN: (纸本)9781424416967

Traditionally, signal processing is considered simply lowlevel processing. In the past decade, however, signal processing has grown to become the area where a variety of tools are created to solve high-level problems that conventionally would be studied by computer vision or machine learning researchers exclusively. For example, multiresolution analysis created popular image features like SIFT (scale-invariant feature transform), and statistical analysis gave birth to graphical models such as HMM (hidden Markov models) and topic models. In this talk, we will use one application to illustrate this growth of signal processing: object discovery, i.e., extracting the "object of interest" from a set of images in a completely unsupervised manner. Often based on image features like SIFT, and the topic models, object discovery has recently attracted a lot of attention in video content extraction. In this talk, we will outline this approach and extend it from still images to motion videos. We will propose a novel spatial-temporal framework that applies statistical models to both appearance modeling and motion modeling. The spatial and temporal models are integrated so that motion ambiguities can be resolved by appearance, and appearance ambiguities can be resolved by motion. In addition, we can extract hierarchical relationships among objects, completely driven by data without any manual labeling. This framework finds application in video retrieval (e.g., for YouTube or Google Video) and video surveillance. © 2007 IEEE.

关键词： Hidden Markov models

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The electronic passport and the future of government-issued RFID-based identification 1

The electronic passport and the future of government-issued ...

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1st IEEE International Conference on RFID, IEEE RFID 2007

作者： Ezovski, G. Watkins, Steve Adaptive Communications and Signal Processing Group School of Electrical and Computer Engineering Cornell University IthacaNY14850 United States Department of Electrical and Computer Engineering University of Missouri-Rolla RollaMO65409 United States

ISBN: (纸本)1424410126

Passports and other identification documents may be enhanced using recent advancements in technology. Various national and international bodies are pursuing machine-readable approaches with biometric information. In particular, the International Civil Aviation Organization (ICAO) has adopted standards whereby passports can store biometric identifiers. Countries that participate in the Visa Waiver Program (VWP) began issuing electronic passports in 2006. However, the selection of technologies remains questionable due to privacy and security concerns. This paper examines policy regarding these electronic approaches and developments toward electronic data storage and transmission. Radio-frequency identification (RFID) devices for electronic passports and other existing identity documents are discussed. © 2007 IEEE.

关键词： Biometrics

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Throughput of two-hop wireless networks with relay cooperation 45

Throughput of two-hop wireless networks with relay cooperati...

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45th Annual Allerton Conference on Communication, Control, and Computing 2007

作者： Niu, Bo Simeone, Osvaldo Haimovich, Alexander M. Somekh, Oren Center for Wireless Communications and Signal Processing Research Department of Electrical and Computer Engineering New Jersey Institute of Technology NewarkNJ07102 United States Department of Electrical Engineering Princeton University PrincetonNJ08544 United States

ISBN: (纸本)9781605600864

In this paper, we consider the throughput problem of a wireless fading network with two-hop relaying, where n single antenna source-destination pairs communicate through a set of single antenna relays using amplify-and-forward strategy Two different cooperation schemes at the relay nodes are considered, where the relays share either channel state information (CSI) or both CSI and received signals. The high level of cooperation is justified for a case where the relaying role is fulfilled by infrastructure nodes that can communicate through a wired backbone without an overhead on the wireless channel. We show that in the first case, at least n2 relays are needed to achieve linear scaling of the system throughput versus n. In the second case, exchanging the received signals at the relays can reduce the needed number of relays to n in order to achieve linear scaling. It is also shown that the second cooperation scheme achieves a strictly positive per node throughput, where the total number of nodes accounted for includes the relays.

关键词： Throughput

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Scalable bata multicast using expanding window fountain codes 45

Scalable bata multicast using expanding window fountain code...

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45th Annual Allerton Conference on Communication, Control, and Computing 2007

作者： Vukobratović, Dejan Stanković, Vladimir Sejdinović, Dino Fagoonee, Lina Xiong, Zixiang Department of Communications and Signal Processing University of Novi Sad Novi Sad Serbia Department of Communication Systems InfoLab 21 Lancaster University Lancaster United Kingdom Centre for Communications Research Department of Electrical and Electronic Engineering University of Bristol Bristol United Kingdom Department of Electrical and Computer Engineering Texas A and M University College StationTX United States

ISBN: (纸本)9781605600864

Digital Fountain (DF) codes were introduced as an efficient and universal Forward Error Correction (FEC) solution for data multicast over lossy packet networks. However, in real-time applications, the DF encoder cannot make use of the "rateless" property as it was proposed in the DF framework, due to its delay constraints. In this scenario, many receivers might not be able to collect enough encoded symbols (packets) to perform succesful decoding of the source data block (e.g., they are connected as a low bit-rate receivers to a high bit-rate source stream, or they are affected by severe channel conditions). This paper proposes an application of recently introduced Expanding Window Fountain (EWF) codes as a scalable and efficient solution for real-time multicast data transmission. We show that, by carefully optimizing EWF code design parameters, it is possible to design a flexible DF solution that is capable of satisfying multicast data receivers over a wide range of data rates and/or erasure channel conditions.

关键词： Forward error correction

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Chesapeake bay water quality monitoring using satellite imagery

Chesapeake bay water quality monitoring using satellite imag...

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作者： Ramakrishna, Bharath Chang, Chein-I. Trou, Bruce Henqemihle, Jerry Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD 21250 Microtel LLC 111 Centerway Greenbelt MD 20770

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 α (Chl-α) 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-α 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. © World Scientific Publishing Company.

关键词： Water quality

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A spatial exploration based blind DOA estimation algorithm for closely spaced sources

A spatial exploration based blind DOA estimation algorithm f...

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Midwest Symposium on Circuits and Systems (MWSCAS)

作者： Feng Wan Wei-Ping Zhu M. N. S. Swamy Centre for Signal Processing and Communications Department of Electrical and Computer Engineering Concordia University Montreal QUE Canada

In this paper, a spatial extrapolation-based blind DOA estimation method is presented for closely spaced sources. The new method is based on the linear extrapolation of the correlation matrix using AR coefficients, which are first estimated through an initial DOA estimation. Both the initial and final DOA estimations are performed by using the ESPRIT algorithm. Unlike conventional AR coefficient estimation method which estimates AR coefficients on the snap-shot basis, our AR coefficient estimation is carried out in correlation domain once a block of snap-shots, thus significantly reducing the computational complexity of the antenna array. computer simulations show that the proposed blind DOA estimation method outperforms the conventional method in terms of the mean square-error (MSE) when the angle of separation of DO As is very small.

关键词： Direction of arrival estimation Extrapolation signal processing algorithms Linear antenna arrays Array signal processing Vectors Interpolation Multiple signal classification Wireless communication Computational complexity

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An Identification Technique for ARMA Systems in the Presence of Noise

An Identification Technique for ARMA Systems in the Presence...

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Canadian Conference on electrical and computer engineering (CCECE)

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 an approach for the identification of minimum-phase autoregressive moving average (ARMA) systems in the presence of additive noise. For the identification of the AR part of an ARMA system, unlike conventional correlation based methods, we propose to employ a once-repeated autocorrelation function (ORACF) of the observed noisy signal which is capable of reducing the effect of additive noise. The ORACF is used in a modified form of the least-squares Yule-Walker equations which provides an estimate of the AR parameters as a least-squares solution. For the identification of the MA part, the residual signal obtained by filtering the observed signal via the estimated AR polynomial is used. In order to tackle the noise in the residual signal, a noise-compensation scheme is proposed. The MA parameters are estimated by using the spectral factorization corresponding to the noise-compensated power spectrum of the residual signal. Simulation results show the superiority of performance by the proposed method in comparison to some of the existing methods at low levels of SNR.

关键词： Noise reduction Parameter estimation Autoregressive processes signal processing Autocorrelation Equations Working environment noise Additive noise Polynomials Speech coding

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A Formant Frequency Estimation Scheme for Speech signals in the Presence of Noise

A Formant Frequency Estimation Scheme for Speech Signals in ...

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URSI International Symposium on signals, Systems, and Electronics (ISSSE)

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

In this paper, a new scheme for the estimation of formant frequencies of noise-corrupted speech signals is presented. A once-repeated autocorrelation function (ORACF) of the observed noisy speech signal is proposed to employ in a linear predictive based formant estimation method. It has been shown that the ORACF is capable of reducing the effect of additive noise significantly and if, instead of conventional ACF, ORACF is used in a modified form of least-squares Yule-Walker equations, a better performance in the formant estimation is achieved. Moreover, a frequency-domain algorithm is incorporated in the proposed scheme to avoid the possible estimation error in extracting a formant with low energy. The proposed algorithm has been tested on synthetic and natural vowels as well as some naturally spoken sentences in the presence of additive noise. The experimental results demonstrate a better performance obtained by the proposed scheme in comparison to some of the existing methods at low levels of signal-to-noise ratio (SNR).

关键词： Frequency estimation Speech enhancement Linear predictive coding Speech analysis Working environment noise Autocorrelation Additive noise Speech synthesis signal processing Equations

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