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Maxwell'S equations, symplectic matrix, and grid

Progress In Electromagnetics Research B 2008年 8卷 115-127页

作者： Sha, W. Wu, X.L. Huang, Z.X. Chen, M.S. Department of Electrical and Electronic Engineering The University of Hong Kong Pokfulam Road Hong Kong Key Laboratory of Intelligent Computing and Signal Processing Anhui University Feixi Road 3 Hefei230039 China Department of Physics and Electronic Engineering Hefei Teachers College Jinzhai Road 327 Hefei230061 China

The connections between Maxwell's equations and symplectic matrix are studied. First, we analyze the continuous-time Maxwell's differential equations in free space and verify its time evolution matrix (TEMA) is symplectic-unitary matrix for complex space or symplectic-orthogonal matrix for real space. Second, the spatial differential operators are discretized by pseudo-spectral (PS) approach with collocated grid and by finite-difference (FD) method with staggered grid. For the PS approach, the TEMA conserves the symplectic-unitary property. For the FD method, the TEMA conserves the symplectic-orthogonal property. Finally, symplectic integration scheme is used in the time direction. In particular, we find the symplectiness of the TEMA also can be conserved. The mathematical proofs presented are helpful for further numerical study of symplectic schemes. © 2008, Electromagnetics Academy.

关键词： Matrix algebra

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Optimized symplectic scheme for electromagnetic simulations

Optimized symplectic scheme for electromagnetic simulations

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Asia-Pacific Conference on Microwave

作者： Bo Wu Zhi-Xiang Huang Wei Sha Ming-Sheng Chen Hong Dai School of physical science and technology Yunnan University China Key Laboratory of Intelligent Computing & Signal Processing Anhui University China Department of Electrical and Electronic Engineering University of Hong Kong Hong Kong China Department of Physics and Electronic Engineering Hefei Teachers College China

Classical finite-difference time-domain (FDTD) method has been widely used in computational electromagnetics, but for electrically large domains and for late-time analysis, FDTD method begins to show its limitations due to the accumulation of phase errors. To solve this problem, several methods have been proposed such as high-order schemes and four-stage Runge-Kutta integrator. Recently, the symplectic methods have been adopted for using in computational electromagnetics. In this paper, the concentration is on the derivation of an optimized fourth-order symplectic scheme in electromagnetic simulations.

关键词： Computational modeling Finite difference methods Permittivity Permeability Maxwell equations Electromagnetic propagation Differential equations Optimization methods Physics computing signal processing

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People re-detection using Adaboost with sift and color correlogram

People re-detection using Adaboost with sift and color corre...

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IEEE International Conference on Image processing

作者： Lei Hu Shuqiang Jiang Qingming Huang Wen Gao Chinese Academy of Sciences Beijing China Key Lab of Intelligent Information Processing Chinese Academy and Sciences Beijing China Chinese Academy of Sciences Beijing Beijing CN Institute of Computing Technology Chinese Academy and Sciences Beijing China Institute of Digital Media Peking University Beijing China

People re-detection aims at performing re-identification of people who leave the scene and reappear after some time. This is an important problem especially in video surveillance scenarios. In this paper, we present a method of people re-detection within the context of visual sequence in single-camera setup. We consider re-detection as a binary classification problem, where both global and local descriptors are employed for training strong classifier on-line with adaboost to distinguish a newly detected people as tracked or new occurrence. The strong classifier will be updated while match is ascertained. A predetermined classifier with well-chosen threshold is employed as assistant of training examples collection. We test the performance of our approach on 4 different scenes including 51 video sequences taken from the CAVIAR database and 4 video sequences shot by ourselves. The results show that our re-detection algorithm can robustly handle variations in illumination, pose, scale, and camera-view.

关键词： Cameras Layout Surveillance Color Video sequences Data mining Joining processes Histograms Information processing Computers

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Manifold-Manifold Distance with Application to Face Recognition based on Image Set

Manifold-Manifold Distance with Application to Face Recognit...

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26th IEEE Conference on Computer Vision and Pattern Recognition (CVPR 2008), vol.9

作者： Ruiping Wang Shiguang Shan Xilin Chen Wen Gao Graduate School of Chinese Academy of Sciences Beijing China Digital Media Research Center Institute of Computing Technology Chinese Academy of Sciences Beijing China Key Lab of Intelligent Information Processing Chinese Academy and Sciences Beijing China School of EE&CS Peking University Beijing China

In this paper, we address the problem of classifying image sets, each of which contains images belonging to the same class but covering large variations in, for instance, viewpoint and illumination. We innovatively formulate the problem as the computation of Manifold-Manifold Distance (MMD), i.e., calculating the distance between nonlinear manifolds each representing one image set. To compute MMD, we also propose a novel manifold learning approach, which expresses a manifold by a collection of local linear models, each depicted by a subspace. MMD is then converted to integrating the distances between pair of subspaces respectively from one of the involved manifolds. The proposed MMD method is evaluated on the task of Face Recognition based on Image Set (FRIS). In FRIS, each known subject is enrolled with a set of facial images and modeled as a gallery manifold, while a testing subject is modeled as a probe manifold, which is then matched against all the gallery manifolds by MMD. Identification is achieved by seeking the minimum MMD. Experimental results on two public face databases, Honda/UCSD and CMU MoBo, demonstrate that the proposed MMD method outperforms the competing methods.

关键词： Face recognition Probes Image converters Content addressable storage Testing Cameras Image storage Video sequences Image recognition Object recognition

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Bayesian-Based Speckle Suppression for SAR Image Using Contourlet Transform

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Journal of Electronic Science and Technology 2008年第1期000卷

作者： De-Xiang Zhang School of Electronic Science and Technology of Anhui University Hefei 230039 China Key Lab. of Intelligent Computing and Signal Processing of MOE Anhui University Hefei 230039 China

A novel and efficient speckle noise reduction algorithm based on Bayesian contourlet shrinkage using contourlet transform is ***,we show the sub-band decompositions of SAR images using contourle transforms,which provides sparse representation at both spatial and directional ***,a Bayesian contourlet shrinkage factor is applied to the decomposed data to estimate the best value for noise-free contourle *** results show that compared with conventional wavelet despeckling algorithm,the proposed algorithm can achieve an excellent balance between suppresses speckle effectively and preserve image details,and the significant information of origina image like textures and contour details is well ma intained.

关键词：转换模式光斑电子技术技术性能

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A Direct-Path Interference Cancellation Approach to Passive Radar Based on Adaptive Fractional Delay Estimation

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电子学报(英文版) 2007年第2期16卷 359-362页

作者： ZHU Jiabing WU Xianliang TAO Liang HONG Yi Education Ministry Key Laboratory of Intelligent Computing and Signal Processing Anhui University Hefei 230039 China Institute of Signal Processing East China Research Institute of Electronic Engineering Hefei 230031 China

Target detection by non-cooperative illuminator is a study hotspot in electronic warfare field, with'four countering' potential advantages for passive radar. One of the major problems in continuous wave bistatic radar is Direct path interference (DPI). Conventional solutions to this problem is the use of an adaptive antenna, steering null towards the interference. Unfortunately the null depth obtained by this technology is not enough for surveillance radar. First of all, DPI appeared in passive radar based on non-cooperative FM broadcast transmitter is analyzed in this paper. Secondly, a DPI cancellation based on Adaptive fractional delay estimation (AFDE) is in detail introduced how to deal with this problem. Finally, a passive radar experimental system based on non-cooperative FM broadcast transmitter is provided, simulation results by real collected data show applying the method proposed in this paper is effective in suppression DPI.

关键词：无源雷达直达波干扰对消自适应分数延迟估计 FM广播

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Study on moving target detection to passive radar based on FM broadcast transmitter

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Journal of Systems Engineering and Electronics 2007年第3期18卷 462-468页

作者： Zhu Jiabing Tao Liang Hong yi Education Ministry Key Lab of Intelligent Computing and Signal Processing Anhui Univ. Hefei 230039 P. R. China Inst. of Signal Processing East China Research Inst. of Electronic Engineering Hefei 230031 P. R. China

Target detection by a noncooperative illuminator is a topic of general interest in the electronic warfare field. First of all, direct-path interference （DPI） suppression which is the technique of bottleneck of moving target detection by a noncooperative frequency modulation（FM） broadcast transmitter is analyzed in this article; Secondly, a space-time-frequency domain synthetic solution to this problem is introduced： Adaptive nulling array processing is considered in the space domain, DPI cancellation based on adaptive fractional delay interpolation （AFDI） technique is used in planned time domain, and long-time coherent integration is utilized in the frequency domain; Finaily, an experimental system is planned by considering FM broadcast transmitter as a noncooperative illuminator, Simulation results by real collected data show that the proposed method has a better performance of moving target detection.

关键词： passive radar direct path interference adaptive beamforming adaptive fractional delay interpolation,long-time coherent integration.

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Determining protein function by protein-protein interaction network

Determining protein function by protein-protein interaction ...

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2007 1st International Conference on Bioinformatics and Biomedical Engineering, ICBBE

作者： Sun, Dengdi Hu, Maolin Lab of Intelligent Computing and Signal Processing Anhui University Hefei 230039 China

ISBN: (纸本)1424411203

Predicting protein function is one of the most challenging problems of the post-genomic era. The development of experimental methods for genome scale analysis of molecular interaction networks has provided new approaches to inferring protein function. There are various approaches available for deducing the function of proteins of unknown function using protein information. In this paper, the reliable methods for assigning protein function are given based on the network of physical interactions. The characteristics of the method are: Function assignment is proteome-wide and is determined by the global connectivity pattern of the protein network. To validate the method, the yeast Saccharomyces cerevisiae protein-protein interaction network is analyzed. Comparing with the current protein function prediction based on network, our method can improve the quality of prediction substantially with multiple data sources. The precision has achieved 82% in the stringent functional classification and 96% in the less detailed classification. © 2007 IEEE.

关键词： Proteins

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signal processing for sound synthesis:: Computer-generated sounds and music for all

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IEEE signal processing MAGAZINE 2007年第2期24卷 8-+页

作者： Valimaki, Vesa Rabenstein, Rudolf Rocchesso, Davide Serra, Xavier Smith, Julius O. Key Lab of Intelligent Perception and Image Understanding of Ministry of Education Xidian University Xi'an China Key Lab of Radar Signal Processing Xidian University Xi'an China

Almost everybody uses sound synthesis in their daily lives, although many may not know it.

关键词： Editors signal processing Music Synthesis of Sound

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A method of multi-user detection based on independent component analysis for DS-CDMA systems

A method of multi-user detection based on independent compon...

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IET Conference on Wireless, Mobile and Sensor Networks 2007, CCWMSN'07

作者： Li, X.H. Gao, W. Cheng, Y. Key Laboratory of Intelligent Computing and Signal Processing Ministry of Education Anhui University Hefei 230039 China

ISBN: (纸本)9780863418365

The DS-CDMA signal model and the noisy linear Independent Component Analysis (ICA) model are analyzed in this paper. Comparing these models shows that they have the same form. The adaptive minimum mean-square error (MMSE) multiuse detection based on ICA is proposed. It uses the output of adaptive MMSE multi-user detection to initialize the ICA iterations, not only the known spread information of interesting user is used to overcome the uncertainness of ICA, but also the character of statistical independence is used. The simulation results show that the performance is improved obviously.

关键词： Mean square error

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