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IEEE 65th Vehicular technology Conference (VTC-Spring 2007), vol.6

作者： Fernando Gregorio Stefan Werner Risto Wichman Juan E. Cousseau Signal Processing Laboratory Helsinki University of Technology Finland Department of Electrical and Computer Engineering Universidad Nacional del Sur Bahia Blanca Argentina

This paper proposes a novel split predistorter structure to remove nonlinear distortion caused by nonlinear power amplifier with memory. Unlike conventional techniques, the new technique does not require an estimation of the memory model at the transmitter leading to a reduced implementation complexity. Simulations have been carried out using the SUI3 channel model developed for IEEE802.16 standard. The results verify the good performance of the proposed predistorter for several relevant power amplifier models.

关键词： Predistortion OFDM Power system modeling Nonlinear distortion Power amplifiers Wireless LAN WiMAX Transmitters Peak to average power ratio Bit error rate

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Face Recognition System Using Ant Colony Optimization-Based Selected Features

Face Recognition System Using Ant Colony Optimization-Based ...

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IEEE Symposium on Computational Intelligence in Security and Defense Applications, CISDA

作者： Hamidreza Rashidy Kanan Karim Faez Mehdi Hosseinzadeh Image Processing and Pattern Recognition Laboratory Electrical Engineering Department Tehran Polytechnic Amirkabir University of Technology슠 Tehran Iran Department of Computer Engineering University of Isfahan Isfahan Iran

Feature selection (FS) is a most important step which can affect the performance of pattern recognition system. This paper presents a novel feature selection method that is based on ant colony optimization (ACO). ACO algorithm is inspired of ant's social behavior in their search for the shortest paths to food sources. In the proposed algorithm, classifier performance and the length of selected feature vector are adopted as heuristic information for ACO. So, we can select the optimal feature subset without the priori knowledge of features. Simulation results on face recognition system and ORL database show the superiority of the proposed algorithm

关键词： Face recognition Ant colony optimization Discrete wavelet transforms Pattern recognition Artificial intelligence Particle swarm optimization Computational intelligence computer security Application software Image processing

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Fast-fading channel estimator using DCT and simplified kalman filter

Fast-fading channel estimator using DCT and simplified kalma...

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IEEE Workshop on Signal processing Advances in Wireless Communications (SPAWC)

作者： J. F. Schmidt J. E. Cousseau R. Wichman F. H. Gregorio CONICET-Department of Electrical and Computer Engineering Universidad Nacional del Sur Bahia Blanca Argentina Signal Processing Laboratory Hut Helsinki University of Technology Finland

We present a novel channel estimator for fading channels using basis function approximations and Kalman filtering. The proposal results in a low complexity estimator that is robust to the shape of the channel Doppler spectrum and allows different Doppler spectra for each channel coefficient in a frequency-selective scenario. The estimator is based on the description of channel variations via truncated discrete cosine transform (DCT). We show that DCT can be approximated by a set of linear narrow-band passband filters that can be inserted into a Kalman filter formulation that track a set of decoupled parameters. This estimator attains close to perfect channel knowledge performance with only 1% training symbols in a data frame with Doppler frequencies up to 0.8 times the frame frequency.

关键词： Discrete cosine transforms Frequency estimation Function approximation Fading Kalman filters Filtering Proposals Robustness Shape Narrowband

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2-D Passive Millimeter Wave Imaging System for plasma Diagnostics

2-D Passive Millimeter Wave Imaging System for Plasma Diagno...

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Asia-Pacific Conference on Microwave

作者： Zuowei Shen C. W. Domier N. C. Luhmann N. Ito A. Mase A.J.H. Donne H. K. Park Department of Electrical and Computer Engineering University of California Davis USA Art Science and Technology Center for Cooperative Research Kyushu University Japan Association EURATOM FOM FOM Institute of Plasma Physics Rijnhuizen Nieuwegein Netherlands Princeton Plasma Physics Laboratory Princeton University USA

technology advances have made possible the visualization of electron temperature profiles and fluctuations inside the core of high temperature plasmas via a two-dimensional passive millimeter wave imaging system. The electron cyclotron emission imaging (ECEI) system concept and configuration are briefly described. Advanced technologies such as frequency selective surfaces band-stop filter, planar Schottky diode mixer arrays, wide bandwidth IF electronics, and imaging optics are presented.

关键词： plasma diagnostics Millimeter wave technology Optical imaging plasma temperature Optical filters Optical arrays Visualization Electrons Fluctuations plasma waves

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Special Issue on Variable Structure System Control — New Designs and Applications

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Asian Journal of Control 2008年第4期5卷

作者： Prof. Jian-Xin Xu Prof. Leonid Fridman Department of Electrical and Computer Eng. National University of Singapore 4 Engineering Drive 3 Singapore 117576 Tel +65 6874-2566 Fax +65 6779-1103 Dr Jian-Xin Xu received his Bachelor degree from Zhejiang University China in 1982. He attended the University of Tokyo Japan where he received his Master's and Ph.D. degrees in 1986 and 1989 respectively. All his degrees are in Electrical Engineering. He worked for one year in the Hitachi research Laboratory Japan and for more than one year in Ohio State University U.S.A. as a Visiting Scholar. In 1991 he joined the National University of Singapore and is currently an associate professor in the Department of Electrical Engineering. His research interests lie in the fields of learning control variable structure control fuzzy logic control discontinuous signal processing and applications to motion control and process control problems. He is the associate editor of Asian Journal of Control member of TC on variable structure systems and sliding mode control of IEEE Control Systems Society and a senior member of IEEE. He has produced more than 90 peer-refereed journal papers near 160 technical papers in conference proceedings and authored/edited 4 books. Division de Estudios de Posgrado Facultad de Ingenieria National Autonomous University of Mexico DEP-FI UNAM Edificio “A” Circuito Exterior Ciudad Universitaria A. P. 70–256 C.P.04510 Mexico D.F. Mexico Tel +52 55 56223014 Fax +52 55 56161719 Dr. Leonid M. Fridman received his M.S in mathematics from Kuibyshev (Samara) State University Russia Ph.D. in Applied Mathematics from Institute of Control Science (Moscow) and Dr. of Science degrees in Control Science from Moscow State University of Mathematics and Electronics in 1976 1988 and 1998 respectively. In 1976–1999 Dr. Fridman was with the Department of Mathematics at the Samara State Architecture and Civil Engineering Academy Samara Russia. In 2000–2002 he was with the Department of Postgraduate Study and Investigations at the Chihuahu

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Novel Applications of Noise in Sensing and Communications

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AIP Conference Proceedings 2007年第1期922卷 405-410页

作者： Laszlo B. Kish Robert Mingesz Zoltan Gingl Gabor Schmera Janusz Smulko Chiman Kwan Peter Heszler Claes‐Goran Granqvist 1Texas A&M University Department of Electrical and Computer Engineering College Station TX 77843‐3128 2University of Szeged Department of Experimental Physics Dom ter 9 Szeged H‐6720 Hungary 3Space and Naval Warfare Systems Center San Diego CA 92152‐5001 4Gdansk University of Technology WETiI ul. G. Narutowicza 11/12 80‐952 Gdansk Poland 5Signal Processing Inc. 13619 Valley Oak Circle Rockville MD 20850 6Research Group of Laser Physics of the Hungarian Academy of Sciences University of Szeged P.O. Box 406 H‐6701 Szeged Hungary 7Department of Engineering Sciences The Ångström Laboratory Uppsala University P.O. Box 534 SE‐751 21 Uppsala Sweden

Recently, it has been shown that excess noises generated or modified by chemical agents can be used to detect and identify chemicals with enhanced sensitivity and selectivity. Moreover thermal noise and its artificial versions (Johnson‐like noises) can be utilized as information carriers with peculiar properties. The first application is called Fluctuation‐Enhanced Sensing. The second class can be called Thermal Noise Informatics with relevant topics are Zero Power Classical Communication and (in the quantum limit) Zero‐Quantum Quantum Communication; Thermal Noise Driven Computing; and Totally Secure Classical Communication. In the paper version of this talk, we will briefly describe the scope of these fields and in the oral talk we also provide extended considerations and results.

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Using context and a genetic algorithm for knowledge-assisted image analysis

Using context and a genetic algorithm for knowledge-assisted...

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1st International Conference on Semantic and Digital Media Technologies, SAMT 2006

作者： Dasiopoulou, Stamatia Papadopoulos, George Th. Mylonas, Phivos Avrtihis, Yannis Kompatsiaris, Ioannis Information Processing Laboratory Electrical and Computer Engineering Department Aristotle University Thessaloniki Greece Informatics and Telematics Institute Centre for Research and Technology Greece Image Video and Multimedia Laboratory School of Electrical and Computer Engineering National Technical University Athens Greece

In this poster, we present an approach to contex-tualized semantic image annotation as an optimization problem. Ontologies are used to capture general and contextual knowledge of the domain considered, and a genetic algorithm is applied to realize the final annotation. Experiments with images from the beach vacation domain demonstrate the performance of the proposed approach and illustrate the added value of utilizing contextual information.

关键词： Ontology

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Predistorter design employing parallel piecewise linear structure and inverse coordinate mapping for broadband communications

Predistorter design employing parallel piecewise linear stru...

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14th European Signal processing Conference, EUSIPCO 2006

作者： Cheong, Mei Yen Werner, Stefan Laakso, Timo I. Cousseau, Juan Figueroa, Jose L. Signal Processing Laboratory Center of Excellence Helsinki University of Technology Finland CONICET Department of Electrical Engineering and Computer Science Universidad Nacional Del sur Bahía Blanca Argentina

This paper proposes a low-complexity predistorter (PD) for compensation of both the AM/AM and the AM/PM conversions with memory. The nonlinear power amplifier (PA) is modeled as a Wiener type nonlinearity. The quasi-static nonlinearities are modeled using a class of piecewise linear (PWL) functions. The PWL function facilitates an efficient PD identification algorithm. The proposed algorithm involves a novel inverse coordinate mapping (ICM) method that maps the nonlinear characteristics of the PA to that of the PD, and parameter estimations that do not require matrix inversion. The indirect learning architecture is used to provide an on-line compensation of thememory effect of the PA. Simulation results show that the PD that compensates also the AM/PM distortion performs significantly better than one that considers only the AM/AM nonlinearity. The proposed PD is also shown to outperform the orthogonal polynomial PD in both adjacent channel interference suppression and inband distortion compensation.

关键词： Power amplifiers

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Silicon-germanium saturable absorber mirrors for ultra-short pulse generation

Silicon-germanium saturable absorber mirrors for ultra-short...

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SiGe and Ge: Materials, processing, and Devices - 210th Electrochemical Society Meeting

作者： Kärtner, F.X. Byun, H. Grawert, F.J. Gopinath, J.T. Shen, H.M. Ippen, E.P. Akiyama, S. Liu, J. Wada, K. Kimerling, L.C. Department of Electrical Engineering and Computer Science Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge MA 02139 United States Materials Processing Center Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge MA 02139 United States

ISBN: (纸本)1566775078

Silicon-Germanium saturable absorber mirrors are developed for laser mode locking. The fabrication process is fashioned such that a highly reflecting Si/SiO2 Bragg mirror with a crystalline absorber top-layer is generated. One step of wafer-bonding allows for subsequent epitaxial growth on the mirror. A six-pair reflector centered at 1400 nm with 99.8% peak reflectivity, a 99%-reflectivity bandwidth of 700 nm and a surface roughness of 0.136 nm is demonstrated. A thin Germanium layer is epitaxially deposited on the mirror surface to provide saturable absorption at 1550nm. with a sub-picosecond recovery time. The device is used to achieve stable, continuously modelocked operation of an Er-Yb:glass laser centered at 1540 nm, generating 220 fs pulses. Copyright The Electrochemical Society.

关键词： Mirrors

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AN EFFICIENT REPRESENTATION OF DIGITAL CURVES WITH LINE SEGMENTS AND ELLIPTICAL ARCS

AN EFFICIENT REPRESENTATION OF DIGITAL CURVES WITH LINE SEGM...

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2006 IET International Conference on Visual Information engineering

作者： C. Paramanand A.N. Rajagopalan Department of Electrical Engineering Image Processing and Computer Vision Laboratory Indian Institute of Technology Chennai India

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