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European Conference on Optical Communication (ECOC)

作者： M. Omella I. Papagiannakis D. Klonidis J.A. Lazaro A.N. Birbas J. Kikidis I. Tomkos J. Prat Signal Theory & Communications Department (TSC) UPC Barcelona Tech Spain Electrical & Computer Engineering Department University of Patras Patras Greece Athens Information Technology Center Athens Greece Analog Integrated Electronic Systems S. A. Greece

The optimum design characteristics to maximize the performance of 10 Gbps full-duplex bidirectional transmission are studied experimentally using a low-bandwidth RSOA assisted by electronic equalization and optimum fi... 详细信息

关键词： Optical filters Design optimization Optical network units Filtering Optical receivers Optical attenuators Passive optical networks Optical noise Band pass filters Bandwidth

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Brain Tissue Classification Using Independent Vector Analysis (IVA) for Magnetic Resonance Image

Brain Tissue Classification Using Independent Vector Analysi...

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IEEE Symposium on Bioinformatics and Bioengineering (BIBE)

作者： Yaw-Jiunn Chiou Hsiang-Min Chen Jyh Wen Chai Clayton Chi-Chang Chen Yen-Chieh Ouyang Wu-Chung Su Ching-Wen Yang San-Kan Lee Chein-I Chang Department of Electrical Engineering National Chung Hsing University Taichung Taiwan Department of Radiology College of Medicine China Medical University and Hospital Taichung Taiwan Department of Radiology Taichung Veterans General Hospital Taichung Taiwan Department of Radiological Technology Central Taiwan University of Science and technology Taichung Taiwan Computer Center Taichung Veterans General Hospital Taichung Taiwan Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore MD USA

The purpose of this study is to present a new method, independent vector analysis (IVA), by extending independent component analysis (ICA) of univariate source signals to multivariate source signals on Magnetic Resonance Imaging (MRI). IVA is utilized to relief the limitation of the conventional ICA approach. The proposed method can resolve the permutation problem during individual ICA runs for group brain MR images. The proposed IVA method in conjunction with support vector machine (SVM), we can effectively separate the different part of gray, white matter and cerebrospinal fluid (CSF) from brain soft tissues. In order to demonstrate the proposed IVA-SVM method, experiments are conducted for performance analysis and evaluation. Simulation results show that using IVA can greatly release from the problem cause from traditional ICA to the situation of analyzing inconsistent results of MR image.

关键词： Brain Image analysis Magnetic analysis Magnetic resonance Independent component analysis Magnetic resonance imaging Support vector machines signal analysis Image resolution signal resolution

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Upper bounds for the secure key rate of the decoy-state quantum key distribution

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Physical Review A 2009年第3期79卷 032335-032335页

作者： Marcos Curty Tobias Moroder Xiongfeng Ma Hoi-Kwong Lo Norbert Lütkenhaus Department of Signal Theory and Communications ETSI Telecomunicación University of Vigo Campus Universitario E-36310 Vigo (Pontevedra) Spain Institute for Quantum Computing University of Waterloo Waterloo Ontario Canada N2L 3G1 Quantum Information Theory Group Institut für Theoretische Physik I and Max-Planck Research Group Institute of Optics Information and Photonics University of Erlangen–Nürnberg 91058 Erlangen Germany Department of Electrical and Computer Engineering and Department of Physics Center for Quantum Information and Quantum Control (CQIQC) University of Toronto Toronto Ontario Canada M5S 3G4

The use of decoy states in quantum key distribution (QKD) has provided a method for substantially increasing the secret key rate and distance that can be covered by QKD protocols with practical signals. The security analysis of these schemes, however, leaves open the possibility that the development of better proof techniques or better classical postprocessing methods might further improve their performance in realistic scenarios. In this paper, we derive upper bounds on the secure key rate for decoy-state QKD. These bounds are based basically only on the classical correlations established by the legitimate users during the quantum communication phase of the protocol. The only assumption about the possible postprocessing methods is that double click events are randomly assigned to single click events. Further, we consider only secure key rates based on the uncalibrated device scenario which assigns imperfections such as detection inefficiency to the eavesdropper. Our analysis relies on two preconditions for secure two-way and one-way QKD. The legitimate users need to prove that there exists no separable state (in the case of two-way QKD) or that there exists no quantum state having a symmetric extension (one-way QKD) that is compatible with the available measurements results. Both criteria have been previously applied to evaluate single-photon implementations of QKD. Here we use them to investigate a realistic source of weak coherent pulses. The resulting upper bounds can be formulated as a convex optimization problem known as a semidefinite program which can be efficiently solved. For the standard four-state QKD protocol, they are quite close to known lower bounds, thus showing that there are clear limits to the further improvement of classical postprocessing techniques in decoy-state QKD.

关键词： Quantum cryptography

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Optical disc detection in retinal images

Optical disc detection in retinal images

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11th International Conference on Optimization of electrical and Electronic Equipment, OPTIM 2008

作者： Ivanovici, M. Scurtu, V. Computers and Electronics Department Faculty of Electrical Engineering and Computer Science Transilvania University Brasov Romania IEEE IEEE Signal Processing and Communications Societies

ISBN: (纸本)1424415446

Lasers are currently used for a wide spectrum of medical applications, including the treatment of eye disorders. When combined with digital image processing techniques, the issue of retinal image segmentation becomes of high importance. In this paper, our purpose is twofold: i) to identify and briefly present the existing approaches for the retinal image segmentation and ii) to test our hypothesis that the Viola-Jones algorithm - initially designed for face detection - can be suited as well for optical disc detection.

关键词： Medical applications

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Building hardware-based low-cost experimental DSP learning modules

Building hardware-based low-cost experimental DSP learning m...

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2008 ASEE Annual Conference and Exposition

作者： Uluagac, A. Williams, Douglas Georgia Institute of Technology School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA United States Department of Undergraduate Affairs Center for Signal and Image Processing Arbutus Center for Distributed Engineering Education

Students often face difficulties in grasping and understanding fundamental digital signal processing (DSP) concepts in the classroom environment. Most DSP courses do not have labs associated with them, and the ones that do typically depend on the usage of text-based programming languages (e.g., MATLAB) that do not allow real-time external hardware interaction. Although the availability of external DSP platforms (e.g. National Instruments Speedy-33, Texas Instruments DSP Student Kits, etc.) for educational purposes has increased because of recent advances in embedded processors and sensor technology, they are rarely used in early DSP courses because of the programming sophistication needed for real-time processing. In this paper we discuss the development of low-cost experimental DSP learning modules for classes that do not usually have a lab component. These modules use National Instruments' Lab VIEW for their programming and development platform with the Speedy-33 DSP board and LEGO Mindstorms NXT Brick as the hardware platforms. Many of the modules can also be run completely on the host computer's sound card. Modules have been developed for examining different aspects of topics such as sampling, aliasing, and filtering, while working with data that has been captured and processed in real-time. Students are able to interact with the hardware and data through GUIs, thus obviating the need to first develop real-time programming skills. This paper will describe these modules and how they are designed to be used both in lectures and as part of homework assignments. © American Society for engineering Education, 2008.

关键词： Digital signal processing

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A cepstral domain algorithm for formant frequency estimation from noise-corrupted speech

A cepstral domain algorithm for formant frequency estimation...

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International Conference on Neural Networks and signal processing

作者： S. A. Fattah W.-P. Zhu M. O. Ahmad Centre for Signal Processing and Communications DepartmentElectrical and Computer Engineering Concordia University Montreal QUE Canada

ISBN: (纸本)9781424423101

A new scheme for the estimation of formant frequencies from noise-corrupted speech signals is presented in this paper. In order to overcome the effect of noise, first, instead of conventional autocorrelation function (ACF), a once-repeated ACF of the observed data is employed. A ramp cosine cepstrum model of the ORACF of speech signal is developed, followed by a model-fitting based least-square optimization to extract the formants. For the purpose of implementation, the discrete cosine transform (DCT) is used which offers computational advantages for real signals and solves the phase unwrapping problem. Synthetic and natural vowels as well as some naturally spoken sentences in noisy environments are tested. 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.

关键词： signal to noise ratio Speech Estimation Discrete cosine transforms Frequency estimation Noise Noise measurement

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A closed-form semi-blind solution to MIMO-OFDM channel estimation

A closed-form semi-blind solution to MIMO-OFDM channel estim...

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International Conference on Neural Networks and signal processing

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

ISBN: (纸本)9781424423101

Semi-blind channel estimation as a combination of the training-based or pilot-assisted method and a pure blind approach is considered to be a feasible solution for practical wireless systems due to its better estimation accuracy as well as spectral efficiency. However, in the existing semi-blind channel estimation techniques, the weighting factor employed to trade off the training-based and the blind criteria has not been appropriately determined. In this paper, a closed-form solution is developed for semi-blind channel estimation of MIMO-OFDM systems. An appealing scheme for the computation of the weighting factor is proposed, leading to an analytical expression for the weighting factor in terms the MSE (mean square error) of the training-based criterion and that of the blind part. A number of computer simulation-based experiments are conducted, confirming the effectiveness of the derived semi-blind solution.

关键词： Channel estimation OFDM MIMO Estimation Receiving antennas signal processing Training

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A Temporal Matching Method for Pitch Determination from Noisy Speech signals

A Temporal Matching Method for Pitch Determination from Nois...

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51st Midwest Symposium on Circuits and Systems (MWSCAS 2008), vol.2

作者： C. Shahnaz W. P. Zhu M. O. Ahmad Centre for Signal Processing and Communications Department of Electrical and Computer Engineering Concordia University Montreal QUE Canada

A new method based on temporal matching is presented in this paper for pitch determination from noisy speech signals. At first, a variable-length average magnitude sum function (VLAMSF) that exhibits a periodicity similar to the pitch period of the voiced speech, has been proposed. We argue that the Discrete Cosine Transform (DCT) power spectrum of the VLAMSF is capable of revealing an estimate of a pitch-harmonic (PH) more accurately even in a heavy noisy scenario. Then, exploiting the extracted PH, we formulate an impulse train with a variable-period that is used to temporally match the periodicity of the proposed VLAMSF for pitch determination. It has been shown through extensive simulations using the Keele database that our new approach consistently outperforms the other existing methods especially at low signal-to-noise ratios (SNRs).

关键词： Speech Noise measurement Discrete cosine transforms signal to noise ratio Speech processing Harmonic analysis Databases

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An algorithm for the identification of autoregressive moving average systems from noisy observations

An algorithm for the identification of autoregressive moving...

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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 algorithm for the parameter estimation of minimum-phase autoregressive moving average (ARMA) systems from noise-corrupted observations. In order to estimate the AR parameters of the ARMA system, an enhanced autocorrelation function (ACF) of the observed data is employed in a modified form of least-squares Yule-Walker equations. For the estimation of the MA parameters, first, a noise-subtraction algorithm is proposed to reduce the effect of noise from the residual signal which is obtained by filtering the noisy ARMA signal via the estimated AR parameters. The MA parameters are then estimated by using the spectral factorization corresponding to the noise-compensated residual signal. computer simulations are carried out for ARMA systems of different orders and simulation results demonstrate a superior identification performance in terms of estimation accuracy and consistency under noisy conditions.

关键词： Working environment noise Parameter estimation signal processing algorithms Equations Noise reduction signal processing Autocorrelation computer simulation Autoregressive processes System identification

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A method for pitch estimation from noisy speech signals based on a pitch-harmonic extraction

A method for pitch estimation from noisy speech signals base...

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International Conference on Neural Networks and signal processing

作者： C. Shahnaz W. -P. Zhu M. O. Ahmad Centre for Signal Processing and Communications Department of Electrical and Computer Engineering Concordia University Montreal QUE Canada

ISBN: (纸本)9781424423101

A new method for pitch estimation from noisy speech signals based on a pitch-harmonic extraction is presented in this paper. At first, a variable-length average magnitude difference function (VLAMDF) that is able to alleviate the adverse effects of intrinsic falling minima of the conventional AMDF, has been proposed. We argue that the fast Fourier transform (FFT) power spectrum of the VLAMDF is capable of revealing an estimate of a pitch-harmonic (PH) more accurately even in a heavy noisy scenario. Then, exploiting the extracted PH, a two-fold criterion is developed in the FFT domain to acquire the corresponding harmonic number for the determination of the pitch. The superior efficacy of the proposed pitch estimator relative to some of the existing ones is confirmed through simulation results using the Keele database.

关键词： Pitch estimation coordinated mining Voice signal Noise Fast Fourier transform Speech PH signals PITCHES pitch

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