检索结果-内蒙古大学图书馆

2011年无线通信与信号处理国际会议(WCSP 2011)

作者： Ying Hu Guizhu Wang Yuling Ouyang Lianhai Shan Zhi Yuan Key laboratory of Intelligent Computing & Signal Processing Ministry of Education Anhui University Key laboratory of Intelligent Computing & SignalProcessing Ministry of Education Anhui UniversityHe Shanghai Research Center for Wireless CommunicationsKey Lab of Wireless Sensor Network & Communicati

In a Bluetooth Low Energy (BTLE) piconet, the master node controls the channel access by a simple polling scheme. Due to an absence of coordination among independent master nodes while accessing the wireless medium, devices will encounter high packet interference if many piconets are simultaneously operating in the same area. In this paper, we propose two schemes in the converged BTLE and cellular network, one is based on bad channel prediction for the BTLE piconets, and the other is based on frequency hopping sequences transformation. We compare the performance of the proposed algorithms with original scheme in the form of channel collision probability and new signaling overhead. The simulation results show that the proposed schemes can reduce channel collision probability significantly and simultaneously the new signaling overhead introduced to the downlink is not large.

关键词： Bluetooth Low Energy(BTLE) piconets cellular network interference channel collision probability

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FAST COMPUTATION OF WIDEBAND RCS USING CHARACTERISTIC BASIS FUNCTION METHOD AND ASYMPTOTIC WAVEFORM EVALUATION TECHNIQUE

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Journal of Electronics(China) 2010年第4期27卷 453-457页

作者： Sun Yufa Du Yan Shao Yong Key Lab. of Intelligent Computing and Signal Processing Ministry of Education Anhui University Hefei 230039 China

The Asymptotic Waveform Evaluation (AWE) technique is an extrapolation method that provides a reduced-order model of linear system and has already been successfully used to analyze wideband electromagnetic scattering problems. As the number of unknowns increases, the size of Method Of Moments (MOM) impedance matrix grows very rapidly, so it is a prohibitive task for the computation of wideband Radar Cross Section (RCS) from electrically large object or multi-objects using the traditional AWE technique that needs to solve directly matrix inversion. In this paper, an AWE technique based on the Characteristic Basis Function (CBF) method, which can reduce the matrix size to a manageable size for direct matrix inversion, is proposed to analyze electromagnetic scattering from multi-objects over a given frequency band. Numerical examples are presented to il-lustrate the computational accuracy and efficiency of the proposed method.

关键词： Method of Moments (MOM) Radar Cross Sections (RCS) Characteristic Basis Func-tion (CBF) method Asymptotic Waveform Evaluation (AWE) Multi-objects

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SAR image despeckling via Bayesian shrinkage based on nonsubsampled contourlet transform

SAR image despeckling via Bayesian shrinkage based on nonsub...

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2010 International Conference on Computational and Information Sciences, ICCIS2010

作者： Zhang, De-Xiang Gao, Qing-Wei Wu, Xiao-Pei Key Lab. of Intelligent Computing and Signal Processing Ministry of Education Anhui University Hefei China

ISBN: (纸本)9780769542706

We propose a novel and efficient SAR image despeckling via Bayesian shrinkage based on nonsubsampled contourlet transform, which has been recently introduced. Despeckling by means of contourlet transform introduce many visual artifacts due to the Gibbs-like phenomena. Nonsubsampled contourlet transform is a flexible multiscale, multidirection and shift-invariant image decomposition that can be efficiently implemented via transform. A Bayesian estimator is applied to the decomposed contourlet coefficients of the logarithmically transformed image to estimate the best value for the noise-free signal. Experimental results show that compared with conventional wavelet despeckling algorithm, the proposed algorithm can achieve an excellent balance between suppresses speckle effectively and preserves image details, and the significant information of original image like textures and contour details is well maintained. © 2010 IEEE.

关键词： Shrinkage

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Fast calculation of wide-band RCS for three-dimensional PEC objects based on preconditioned AWE technique

Fast calculation of wide-band RCS for three-dimensional PEC ...

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

作者： Zhao, Ke-Ming Sun, Yu-Fa Key Lab. of Intelligent Computing and Signal Processing Ministry Education Anhui University Hefei 230039 China

ISBN: (纸本)9781424463558

The asymptotic waveform evaluation (AWE) technique combined with the method of moments (MOM) is often applied to accelerate the calculation of the wide-band radar cross section (RCS) of the target. However, the technique is still quite time-consuming for solving the inverse of impedance matrix when the objects are electrically large. In this paper, Krylov subspace iterative methods are applied to solve the matrix equation derived from electric field integral equation instead of matrix inverse. The dual threshold incomplete LU factorization preconditioner is adopted to improve the convergence behavior of the Krylov subspace iterative methods. The numerical computation shows that the results in this paper are in good agreement with the results obtained by the method of moments at each frequency, and the computational efficiency is improved greatly. © 2010 IEEE.

关键词： Method of moments

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GPU-based accelerated FDTD simulations for double negative (DNG) materials applications

GPU-based accelerated FDTD simulations for double negative (...

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2010 International Conference on Microwave and Millimeter Wave Technology, ICMMT 2010

作者： Chen, Shen Dong, Sun Xian-Liang, Wu Key Lab. of Intelligent Computing and Signal Processing Anhui University Ministry of Education Hefei 230039 China

ISBN: (纸本)9781424457052

Recently, double-negative meta-materials are widely studied in scientific research. The double-negative (DNG) mediums are characterized by simultaneous negative permittivity and permeability. In order to make the FDTD method analyze the electromagnetic scattering and propagation for doublenegative (DNG) medium, z-transform is applied to the FDTD method in the double-negative (DNG) medium. For the simulations, extremely large computer memory space and a long computational time is required. A parallel algorithm for the FDTD method on the state of the art graphics hardware is presented. The parallel computing techniques can be used to reduce the computation time significantly and have been widely applied in various complex FDTD applications. In this paper, we simulate the interaction between electromagnetic wave and DNG medium, and describe an impact of new GPU features on development process of an efficient Finite Difference Time Domain (FDTD) implementation. © 2010 IEEE.

关键词： Finite difference time domain method

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An efficient technique for extracting singularity arising in RCS computation of cylindrical antenna

An efficient technique for extracting singularity arising in...

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2010 International Conference on Microwave and Millimeter Wave Technology, ICMMT 2010

作者： Li, Jing Sun, Yufa Key Lab. of Intelligent Computing and Signal Processing Anhui University Ministry Education Hefei 230039 China

ISBN: (纸本)9781424457052

Analysis of electromagnetic scattering characteristics from wire antennas using method of moments has been performed over the past decades. In this paper, an efficient technique is adopted to evaluate the potential and reaction integrals arising in radar cross section (RCS) computation of cylindrical antenna by method of moments. The singularity of potential and reaction integrals is extracted through the semi-analytical method. The induced current on the surface and RCS of cylindrical antenna are calculated. Numerical examples are presented to illustrate the computational accuracy and efficiency of the proposed technique. © 2010 IEEE.

关键词： Radar cross section

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A Regularized Super Resolution Algorithm for Generalized Gaussian Noise

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Journal of Donghua University(English Edition) 2010年第1期27卷 25-35页

作者：陈文方向忠刘立峰蒋伟丁大为乔艳涛 Institute of Image Communication and Information Processing Shanghai Jiaotong University Computer and Information Department Shanghai University of Electric Power Key Lab oratory of Intelligent Computing & Signal Processing Ministry of EducationAnhui University

In this paper,an iterative regularized super resolution (SR) algorithm considering non-Gaussian noise is *** on the assumption of a generalized Gaussian distribution for the contaminating noise,an lp norm is adopted to measure the data fidelity term in the cost *** the meantime,a regularization functional defined in terms of the desired high resolution (HR) image is employed,which allows for the simultaneous determination of its value and the partly reconstructed image at each iteration *** convergence is thoroughly *** results show the effectiveness of the proposed algorithm as well as its superiority to conventional SR methods.

关键词： super resolution generalized p-Gaussian distribution regularization parameter

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An automatic image annotation method based on the mutual K-nearest neighbor graph

An automatic image annotation method based on the mutual K-n...

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International Conference on Natural Computation

作者： Guo, Yu Tang Luo, Bin Department of Computer Science and Technology Hefei Normal University Hefei China Key Lab. of Intelligent Computing and Signal Processing Anhui University Hefei China

ISBN: (纸本)9781424459612

In order to improve the accuracy of the image annotation, an automatic image annotation method based on mutual K-nearest neighbor graph(MKNN) is proposed. The peoposed algorithm describes the relationship between low-level features, annotation words and image by a mutual K-nearest neighbor graph. Semantic information is extracted by exploitingt the mutual relationship of two nodes in the mutual K-nearest neighbor graph. Inverse document frequency (IDF) is introduced to adjust the weights of edges between the image node and its annotation word's node, which overcomes the deviation caused by high-frequency words. Experimental results in Corel image dataset show that the proposed algorithm improves effectively the image annotation performance. ©2010 IEEE.

关键词： Image annotation

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An efficient splitting the plane-wave FDTD method

An efficient splitting the plane-wave FDTD method

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2010 International Conference on Microwave and Millimeter Wave Technology, ICMMT 2010

作者： Hui, Wang Zhi-Xiang, Huang Xian-Liang, Wu Xiao-Yong, Liu Key Lab. of Intelligent Computing and Signal Processing Anhui University Ministry of Education Hefei China Department of Physics and Electronic Engineering Hefei Normal University Hefei China

ISBN: (纸本)9781424457052

The paper presents a new efficient method of introduction of plane wave source into finite difference time domain (FDTD) grids: the method of splitting the plane-wave FDTD (SP-FDTD). The new equations for the 1-D propagator are based on spitted-field Maxwell's equations, and the propagator makes the 1-D and 2-D dispersion equations identical. The technique virtually eliminates numerical dispersion, filed location and polarization mismatches between propagator and main grid, for a plane wave propagating at an angle forming an integer grid cell ratio, which can represent almost any angle in theory. Through the leak test of the different incident angles of the Gauss pulse plane wave source in 2-D, it shows that, the technique can achieve a perfect total-field scattered-field separation, making leakage down to -340 dB levels. © 2010 IEEE.

关键词： Maxwell equations

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The SP-FDTD method for high-order FDTD plane wave injection

The SP-FDTD method for high-order FDTD plane wave injection

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2010 9th International Symposium on Antennas Propagation and EM Theory, ISAPE 2010

作者： Wang, Hui Huang, Zhi-Xiang Wu, Xian-Liang Sun, Jia-Xun Ren, Xin-Gang Wu, Lei Key Lab. of Intelligent Computing and Signal Processing Anhui University Ministry of Education Hefei China Department of Physics and Electronic Engineering Hefei Normal University Hefei China

ISBN: (纸本)9781424469062

In the paper, the method of splitting plane wave FDTD (SP-FDTD) algorithm, an efficient method of introducing plane wave source into finite difference time domain grids, is presented for solving oblique incident wave for the modified high-order FDTD (M24 scheme). Numerical examples in 2-D demonstrate the valid of the method and normalized field leakage was measured at -320 dB levels. ©2010 IEEE.

关键词： Numerical methods

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