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Power Tech Conference

作者： George Papaefthymiou Jody Verboomen Lou van der Sluis Electrical Power System Laboratory (EPS) Faculty of Electrical Engineering Mathematics ' Computer Science Delft University of Technnology Delft Netherlands

The incorporation of wind power generation to the power system leads to an increase in the variability of the system power flows. The assessment of this variability is necessary for the planning of the necessary system reinforcements. For the assessment of this variability, the uncertainty in the system inputs should be modeled, comprising of the time-dependent stochasticity of the system loads and the correlated wind resources. In this contribution, a unified Monte-Carlo simulation methodology is presented that addresses both issues. The application of the method for the analysis of the wind power integration in the New England test system is presented.

关键词： Power systems Wind energy Power system modeling Wind energy generation Wind power generation Load flow Wind speed Stochastic systems Power generation Power system planning

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Explicit Stability Conditions for FDTD on Nonuniform Tensor-Product Grids

Explicit Stability Conditions for FDTD on Nonuniform Tensor-...

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International Conference on Electromagnetics in Advanced Applications (ICEAA)

作者： R. F. Remis Laboratory of Electromagnetic Research Mathematics and Computer Science Faculty of Electrical Engineering Delft University of Technnology Delft Netherlands

In this paper we present sufficient conditions for stability of the finite-difference time-domain method on nonuniform tensor-product grids. The general Courant-Friedrichs-Lewy stability condition can be written in terms of the spectral radius of the first-order Maxwell system matrix. In this paper we present upper bounds for this spectral radius and we use these bounds to obtain sufficient conditions for stability of FDTD in one, two, and three dimensions. The stability conditions are all presented in terms of the maximum electromagnetic wave speed present in the configuration and the minimum step sizes of the grid. Moreover, our conditions reduce to the well-known stability conditions for FDTD if the grid is uniform.

关键词： Stability Finite difference methods Time domain analysis Sufficient conditions Upper bound Maxwell equations Electromagnetic scattering Nonuniform electric fields Space technology Boundary conditions

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Companding Baseband Switched Capacitor Filters and ADCs for WLAN Applications

Companding Baseband Switched Capacitor Filters and ADCs for ...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： Vaibhav Maheshwari Wouter A. Serdijn John R. Long Electronics Research Laboratory Faculty of Electrical Engineering Mathematics and Computer Science Delft University of Technnology Delft Netherlands

In this paper, system level design techniques for companding baseband switched capacitor (SC) filters for WLAN applications are presented. With companding, no AGC is required in front of the filter. A filter prototype is designed for 802.11g receiver and simulation results show that, with careful design of the opamps, a total harmonic distortion of less than 0.5% can be achieved. A new type of companding ADCs along with the algorithm to achieve companding in ADCs is proposed. It is shown that companding by a factor of 4 reduces the power consumption of the SC filter by a factor close to 4 times for a given dynamic range whereas it directly results in 12 dB reduction in the dynamic range requirement of the following ADC.

关键词： Baseband Capacitors Filters Wireless LAN Dynamic range Signal processing Energy consumption Application software System-level design CMOS technology

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An Efficient Krylov Subspace Method to Simulate the Low-Frequency Response of Multiconductor Transmission Lines

An Efficient Krylov Subspace Method to Simulate the Low-Freq...

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2007 International Conference on Electromagnetics in Advanced Applications (ICEAA 2007), vol.2

作者： R. F. Remis Laboratory of Electromagnetic Research Faculty of Electrical Engineering Mathematics and Computer Science Delft University of Technnology Delft Netherlands

In this paper we present a Krylov subspace method to efficiently compute the low-frequency response of multiconductor transmission lines. Through a Lanczos-type algorithm we generate so-called spectral Lanczos decomposition approximations on an entire frequency interval of interest. Low frequencies are approximated first, since we use the inverse of the transmission line system matrix in the Lanczos algorithm. Although this inverse is not a sparse matrix, computing its action on a vector still requires an order N amount of work, where N is the total number of unknowns. Moreover, the inverse is a so-called J-symmetric matrix because of reciprocity. This property is exploited in the Lanczos algorithm and approximations are constructed via a three-term recurrence relation. The overall algorithm is therefore very efficient.

关键词： Multiconductor transmission lines Transmission line matrix methods Voltage Equations Frequency Sparse matrices Transmission lines Boundary conditions Computational modeling Matrix decomposition

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Color Based Texture - Classification of Hysteroscopy Images of the Endometrium

Color Based Texture - Classification of Hysteroscopy Images ...

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

作者： M. S. Neofytou V. Tanos M. S. Pattichis C. S. Pattichis E. C. Kyriacou S. Pavlopoulos Department of Computer Science University of Cyprus Nicosia Cyprus Areteion Hospital Nicosia Cyprus Department of Electrical and Computer Engineering University of New Mexico USA Biomedical Engineering Laboratory Department of Electrical and Computer Engineering National and Technical University of Athens Greece

The objective of this study was to develop a CAD system for the classification of hysteroscopy images of the endometrium based on color texture analysis for the early detection of gynaecological cancer. A total of 416 Regions of Interest (ROIs) of the endometrium were extracted (208 normal and 208 abnormal) from 40 subjects. RGB images were gamma corrected and were converted to the HSV and YCrCb color systems. The following texture features were extracted for each channel of the RGB, HSV, and YCrCb systems: (i) statistical features, (ii) spatial gray level dependence matrices and (iii) gray level difference statistics. The PNN statistical learning and SVM neural network classifiers were also investigated for classifying normal and abnormal ROIs. Results show that there is significant difference (using the Wilcoxon Rank Sum Test at a=0.05) between the texture features of normal and abnormal ROIs of the endometrium. Abnormal ROIs had higher gray scale median, variance, entropy and contrast and lower gray scale median and homogeneity values when compared to the normal ROIs. The highest percentage of correct classifications score was 79 % and was achieved for the SVM models trained with the SF and GLDS features for differentiating between normal and abnormal ROIs. Concluding, a CAD system based on texture analysis and SVM models can be used to classify normal and abnormal endometrium tissue. Further work is needed to validate the system in more cases and organs.

关键词： Support vector machines Support vector machine classification Image color analysis Image analysis Image texture analysis Cancer detection Image converters Feature extraction Matrix converters Statistics

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Velocity extraction from spin-tagging MRI images using a weighted least-squares optical flow method

Velocity extraction from spin-tagging MRI images using a wei...

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IEEE International Workshop on Imaging Systems and Techniques (IST)

作者： John Stoitsis Effi Bastouni Dimitrios C. Karampinos John C. Bosshard Jiaxi Lu Spyretta Golemati Steven M. Wright John G. Georgiadis Konstantina S. Nikita Biomedical Simulations and Medical Imaging Laboratory Faculty of Electrical and Computer Engineering National and Technical University of Athens Greece Department of Mechanical Science and Engineering and Beckman Institute University of Illinois Urbana-Champaign Urbana IL USA Department of Electrical and Computer Engineering Texas A and M University College Station TX USA

Magnetic resonance imaging (MRI) can provide truly non-invasive measurements of internal flow fields. The extraction of velocity from spin-tagging images requires the quantitative tracking of grid nodes. A weighted least-squares optical flow method was used in this work to estimate the displacements of the grid nodes and tags from synthetic and real spin-tagging MRI images. To investigate the accuracy of the proposed method, synthetic spin-tagging images were generated using the Poiseuille law analytical profile. Three synthetic sequences with different levels of noise were generated and the average and maximum absolute errors were estimated for points corresponding to grid nodes and tags. Different sizes and shapes of region of interest (ROI) were investigated to determine the optimal size and shape for reliable extraction of velocity both for synthetic and real spin-tagging MRI images. The optimal ROI size was found to be 13x13 pixels 2 . The average and maximum absolute error for the velocity in vertical direction for synthetic data using the optimal ROI size ranged from 5.46% to 14.42% and from 6.39% to 31.96% respectively.

关键词： Magnetic resonance imaging Image motion analysis Shape Fluid flow measurement Magnetic field measurement Image generation Image analysis Noise shaping Noise generators Noise level

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Intelligent Data Analysis for Diagnostics of Alcohol Dependency

Intelligent Data Analysis for Diagnostics of Alcohol Depende...

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Annual IEEE Symposium on computer-Based Medical Systems

作者： Petra Povalej Matej Kravos Peter Kokol Laboratory for System Design Faculty of Electrical Engineering and Computer Science University of Maribor Slovenia Psychiatric Hospital Ormož Ormoz Slovenia

The alcohol dependency is hard to diagnose since none of the existing laboratory markers has sufficient specificity and sensitivity. Therefore the goal of our study was to find better laboratory markers and / or their combinations. For that purpose the intelligent data analysis using the decision tree induction method was used. The results show that the combination of three or even two markers can prove alcohol dependency with almost 85% accuracy. However the remark has to be made that the induced decision tree offers a qualitatively different access to diagnostic evaluation of laboratory findings and varies from common practice, because it sets up its new and own borders and criteria what is the unlike from generally accepted or set up reference values. All selected markers are widely accessible, inexpensive and part of a routine laboratory tests.

关键词： Data analysis Laboratories Decision trees Medical diagnostic imaging Alcoholism Testing Biochemistry Databases Decision making Learning systems

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Contributors to the Lab on a Chip cell and tissue engineering in microsystems special issue

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Lab on a Chip 2007年第6期7卷 667-671页

作者： Bhatia, Sangeeta N. Chen, Christoper Bashir, Rashid Beebe, David J. Desai, Tejal Gottwald, Eric Khademhosseini, Ali Langer, Robert S. Piel, Matthieu Takayama, Shuichi Thorsen, Todd Tien, Joe Voldman, Joel Vunjak-Novakovic, Gordana Wu, Mingming Yu, Hanry Massachusetts Institute of Technology Harvard-MIT Division of Health Sciences and Technology Department of Electrical Engineering and Computer Science United States Laboratory for Multiscale Regenerative Technologies United States Department of Innovation University of Pennsylvania Department of Bioengineering United States Cell Biology and Physiology Program Cell Growth and Cancer Program Tissue Microfabrication Laboratory Department of Electrical and Computer Engineering and Biomedical Engineering Purdue University United States Department of Electronics University of Glasgow United Kingdom Department of Physiology and Bioengineering University of California San Francisco CA United States California Institute for Quantitative Biomedical Research UCSF/UC Berkeley Graduate Group in Bioengineering United States Laboratory of Therapeutic Micro and Nanotechnology Institute for Biological Interfaces Germany 3D-Cell Culture Techniques Group Institute for Biological Interfaces Germany Department of Medicine and Health Sciences and Technology Massachusetts Institute of Technology (MIT) United States Institut Curie UMR 144 IC/CNRS France Biomedical Engineering Department University of Michigan United States Department of Biomedical Engineering Macromolecular Science and Engineering Program United States Sibley School of Mechanical and Aerospace Engineering School of Chemical and Molecular Engineering Cornell University United States National University of Singapore Singapore Institute of Bioengineering and Nanotechnology A STAR Singapore

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An Initial Rotor Position Estimation Method for Switched Reluctance Motor without Using Machine Parameter

An Initial Rotor Position Estimation Method for Switched Rel...

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International Conference on electrical Machines and Systems 2007(ICEMS2007)(第十届国际电机与系统会议)

作者： K. Tungpimolrut S. Kachapornkul P.Somsiri P. Jitkreeyarn Tadashi Fukao Akira Chiba Industrial Control and Automation Laboratory Section National Electronics and Computer Technology C Department of Electrical Engineering Faculty of Science and Technology Tokyo University of Science

In this paper a method to estimate the initial rotor position of the switched reluctance motor (SRM) at the stand still condition is proposed. The proposed method can be implemented by the simple microcontroller based system, and it is not necessary to know the magnetization curves. The impulse gate drive signal is applied and the winding current is detected and its approximate value is used for calculating the rotor position. The compensation method to reduce the estimation error thorough one cycle is also mentioned. The proposed method is implemented with the 6-stator-pole and 4- rotor-pole, 1.5 kW 3-phase switched reluctance motor.

关键词： Switched reluctance motor initial rotor position estimation

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Wavelet-based despeckling of SAR images using Gauss-Markov random fields

Wavelet-based despeckling of SAR images using Gauss-Markov r...

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作者： Gleich, Dušan Datcu, Mihai IEEE Laboratory for Signal Processing and Remote Control Faculty of Electrical Engineering and Computer Science University of Maribor 2000 Maribor Slovenia Remote Sensing Technology Institute IMF 82234 Weßling Germany Paris Institute of Technology GET Telecom Paris University Politechnica of Bucharest Bucharest Romania

In this paper, a wavelet-based speckle-removing algorithm is represented and tested on synthetic aperture radar (SAR) images. The SAR image is first transformed using a dyadic wavelet transform. The noise in the wavelet-transformed image is modeled as an additive signal-dependent noise with Gaussian distribution. The distribution of a noise-free image in a wavelet domain is modeled as a generalized Gauss-Markov random field (GGMRF). An unsupervised stochastic model-based approach to image denoising is represented. If the observed area is homogeneous, the parameters of the Gaussian distribution and GGMRFs are estimated from incomplete data using mixtures of wavelet coefficients. An expectation-maximization algorithm is used to estimate the parameters of both noisy and noise-free images. The unknown parameters are estimated using image and noise models that are defined in the wavelet domain for heterogeneous areas. Different inter- and intrascale dependences of wavelet coefficients were used to estimate the unknown parameters. The represented wavelet-based method efficiently removes noise from SAR images. © 2007 IEEE.

关键词： Radar imaging

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