检索结果-内蒙古大学图书馆

2012 International Conference on Microwave and Millimeter Wave Technology, ICMMT 2012

作者： Shen, Jing Sha, Wei E. I. Huang, Zhixiang Chen, Mingsheng Wu, Xianliang Key Laboratory of Intelligent Computing and Signal Processing Anhui University Hefei 230039 China Department of Electrical and Electronic Engineering University of Hong Kong Pokfulam Road Hong Kong Hong Kong Department of Physics and Electronic Engineering Hefei Normal University Lianhua Road Hefei 230601 China

ISBN: (纸本)9781467321839

A high-order symplectic FDTD (SFDTD) framework for solving the time-dependent Schrödinger equation is established. The third-order symplectic integrators and fourth-order collocated differences are employed in the time and space domains, respectively. The stabilities and numerical dispersions of FDTD(2,2), higher-order FDTD(2,4), and SFDTD(3,4) schemes are analyzed. We found that the stability limit of the SFDTD(3,4) scheme can be larger than that of the traditional FDTD(2,2) method through careful optimization of symplectic integrators. Moreover, the SFDTD(3,4) scheme and the FDTD(2,4) approach show better numerical dispersions than the traditional FDTD(2,2) method. © 2012 IEEE.

关键词： Numerical methods

来源：评论

学校读者我要写书评

暂无评论

A new compressed sensing-based matching pursuit algorithm for image reconstruction

A new compressed sensing-based matching pursuit algorithm fo...

引用

Congress on Image and signal processing, CISP

作者： Hong Fang Hairong Yang School of Science Shanghai Second Polytechnic University Shanghai China Key Laboratory of Intelligent Computing Signal Processing Anhui University Hefei China

Compressed Sensing (CS), a popular technique which seeks to capture a discrete signal with a small number of linear measurements, could be used to compress a signal during the process of sampling. As an iterative greedy reconstruction algorithm for practical CS, sparsity adaptive matching pursuit (SAMP) takes advantage of the capability of signal reconstruction without prior information of the sparsity in the process of resuming the original high-dimension-data from low-dimension measurement. This paper presents a backward and adaptive matching pursuit reconstruction algorithm with fixed step sizes to avoid the overestimation phenomena of SAMP by using a standard regularized approach. Firstly, a fixed and biggish step size is set to make sure the size of support set of the signal to be reconstructed increasing stably. The energy difference between adjacent reconstructed signals is then taken as the halting condition of iteration. A standard regularized approach is employed to post-dispose the final iteration results, which backward eliminates superfluous atoms to acquire exact reconstruction. Experimental results show that such an improvement of SAMP is feasible in technology and effective in acquiring quick and exact reconstruction with sufficient measurement.

关键词： Matching pursuit algorithms Image reconstruction Accuracy Reconstruction algorithms Compressed sensing Minimization Sensors

来源：评论

学校读者我要写书评

暂无评论

Pulse waveform key point recognition by wavelet transform for central aortic blood pressure estimation

引用

Journal of Information and Computational Science 2012年第1期9卷 25-33页

作者： Zheng, Gang Huang, Qingjun Yan, Guodong Dai, Min Tianjin Key Laboratory of Intelligence Computing and Novel Software Technology Tianjin University of Technology Tianjin 300384 China Laboratory of Bio Signal and Intelligent Processing Tianjin University of Technology Tianjin 300384 China

Non invasion estimating of Central Aortic blood Pressure (CAP) is still a hard problem. Through tenyears clinical research plan (CAFE, Conduit Artery Functional Endpoint) on CAP, CAP is a vital sign to evaluate human's vascular condition. It is more valuable than ordinary brachial artery blood pressure. Non invasion estimating of CAP is depended on the key point recognition of radial pulse, especially the peak of tidal wave (left ventricular stopping ejection point, point e). Since someone's point e is not obvious in his/her pulse waveform, orientation of this point has becoming a difficult problem to be tackled. Through deep study on the feature of pulse waveform, an modified wavelet transform is proposed. It is used to recognize point e of pulse waveform by relative displacement between the 4th and 5th scale of a symlet (it is a kind of discrete wavelet transform). After experiments on 16 patients and 20 healthy volunteers, the results support the proposed strategy in recognizing both obvious and unobvious point e of pulse waveform. The CAP can be estimated by the point e accurately, and the results can meet the requirement of clinical diagnosis. © 2012 Binary Information Press January 2012.

关键词： Clinical research

来源：评论

学校读者我要写书评

暂无评论

Numerical dispersion analysis of symplectic and ADI schemes

Numerical dispersion analysis of symplectic and ADI schemes

引用

International Conference on Microwave and Millimeter Wave Technology Proceedings

作者： Xin-gang Ren Zhi-xiang Huang Xian-liang Wu Si-long Lu Yi-cai Mei Hong-mei Du Hui Wang Jing Shen Key Lab of Intelligent Computing & Signal Processing Ministry of Education Anhui University Hefei China Department of Physics and Electronic Engineering Hefei Normal University Hefei China

In this paper, Maxwell's equations are taken as a Hamiltonian system and then written as Hamiltonian canonical equations by using the functional variation method. The symplectic and ADI schemes, which can be extracted by applying two types of approximation to the time evolution operator, are explicit and implicit scheme in computational electromagnetic simulation, respectively. Since Finite-difference time-domain (FDTD) encounter low accuracy and high dispersion, the more accurate simulation methods can be derived by evaluating the curl operator in the spatial direction with kinds of high order approaches including high order staggered difference, compact finite difference and scaling function approximations. The numerical dispersion of the symplectic and ADI schemes combining with the three high order spatial difference approximations have been analyzed. It has been shown that symplectic scheme combining with compact finite difference and ADI scheme combining with scaling function performance better than other methods. Both schemes can be usefully employed for simulating and solving the large scale electromagnetic problems.

关键词： Dispersion Finite difference methods Function approximation Time domain analysis Maxwell equations Mathematical model

来源：评论

学校读者我要写书评

暂无评论

P-type Iterative Learning Control of Fractional Order Nonlinear Time-delay Systems

P-type Iterative Learning Control of Fractional Order Nonlin...

引用

The 24th Chinese Control and Decision Conference (第24届中国控制与决策学术年会 2012 CCDC)

作者： Yong-Hong Lan Lv-Jun He Key Laboratory of Intelligent Computing andInformation Processing of Ministry of Education Xiangtan School of Information Engineering Xiangtan University Xiangtan Hunan 411105 China

This paper presents a P-type iterative learning control (ILC) scheme for a class of fractional-order nonlinear time-delay systems with fractional order α (0 ≤ α < 1). By introducing the λ-norm and using a generalized Gronwall inequality, the *** conditions for the convergence of the control input and the tracking errors for open-loop and closedloop P-type ILC are obtained, respectively. The validity of the methods are *** by a numerical example.

关键词： Fractional order Iterative learning control Generalized Gronwall inequality Convergent

来源：评论

学校读者我要写书评

暂无评论

Perfect plane-wave source for a high-order symplectic finite-difference time-domain scheme

引用

Chinese Physics B 2011年第11期20卷 365-370页

作者：王辉黄志祥吴先良任信钢 Key Laboratory of Intelligent Computing & Signal Processing of Ministry of Education Anhui University Department of Physics and Electronic Engineering Hefei Normal University

The method of splitting a plane-wave finite-difference time-domain （SP-FDTD） algorithm is presented for the initiation of plane-wave source in the total-field / scattered-field （TF/SF） formulation of high-order symplectic finite- difference time-domain （SFDTD） scheme for the first time. By splitting the fields on one-dimensional grid and using the nature of numerical plane-wave in finite-difference time-domain （FDTD）, the identical dispersion relation can be obtained and proved between the one-dimensional and three-dimensional grids. An efficient plane-wave source is simulated on one-dimensional grid and a perfect match can be achieved for a plane-wave propagating at any angle forming an integer grid cell ratio. Numerical simulations show that the method is valid for SFDTD and the residual field in SF region is shrinked down to -300 dB.

关键词： splitting plane-wave finite-difference time-domain high-order symplectic finite-differencetime-domain scheme plane-wave source

来源：评论

学校读者我要写书评

暂无评论

Theory of Pump-Probe Experiments of Metallic Metamaterials Coupled to a Gain Medium

引用

Physical Review Letters 2012年第18期108卷 187402-187402页

作者： Zhixiang Huang Th. Koschny C. M. Soukoulis Ames Laboratory and Department of Physics and Astronomy Iowa State University Ames Iowa 50011 USA Key Laboratory of Intelligent Computing and Signal Processing Anhui University Hefei 230039 China Institute of Electronic Structure and Laser FORTH 71110 Heraklion Crete Greece

We establish a new approach for pump-probe simulations of metallic metamaterials coupled to the gain materials. It is of vital importance to understand the mechanism of the coupling of metamaterials with the gain medium. Using a four-level gain system, we have studied light amplification of arrays of metallic split-ring resonators with a gain layer underneath. We find that the differential transmittance ΔT/T can be negative for split-ring resonators on the top of the gain substrate, which is not expected, and ΔT/T is positive for the gain substrate alone. These simulations agree with pump-probe experiments and can help to design new experiments to compensate for the losses of metamaterials.

关键词： PHYSICS experiments METAMATERIALS ENERGY levels (Quantum mechanics) ELECTRIC resonators SIMULATION methods & models SUBSTRATES (Materials science)

来源：评论

学校读者我要写书评

暂无评论

Generalized two-dimensional FLD with assembled matrix distance metric for face recognition

引用

Journal of Information and Computational Science 2012年第12期9卷 3439-3446页

作者： Shi, Yuexiang Gong, Ping Tao, Zhiping Key Laboratory of Intelligent Computing and Information Processing of Ministry of Education School of Information Engineering Xiangtan University Xiangtan 411105 China School of Information Engineering Xiangtan University Xiangtan 411105 China

Two-dimensional fisher linear discriminant analysis (2DFLD or 2DLDA) has attracted much attention from researchers recently for the advantages over the singularity problem and the computational cost. Recent research on 2DLDA-based methods has mainly concentrated on two issues, namely: 1) feature extraction and 2) classification. In this paper, we further analyze these two problems simultaneously by using G-2DFLD supplemented with an Assembled Matrix Distance (AMD) metric. For feature extraction, G-2DFLD is proposed, which can be used for image feature extraction by reducing the dimensionality in both horizontal and vertical directions. For classification, an AMD metric is presented to calculate the distance between two feature matrices, then, the nearest neighbor classifier is used for face recognition. To test this new method, ORL face database is used and the results show the efficiency of G-2DFLD with AMD metric in face recognition. © 2012 Binary Information Press.

关键词： Feature extraction

来源：评论

学校读者我要写书评

暂无评论

A novel segmentation method for convex lesions based on dynamic programming with local intra-class variance 12

A novel segmentation method for convex lesions based on dyna...

引用

27th Annual ACM Symposium on Applied computing, SAC 2012

作者： Yu, Mali Huang, Qiliang Jin, Renchao Song, Enmin Liu, Hong Hung, Chih-Cheng School of Computer Science Huazhong University of Science and Technology Wuhan China Key Laboratory of Education Ministry for Image Processing and Intelligent Control Wuhan Hubei China Radiology Department Second People's Hospital of Nanning Nanning China School of Computing and Software Engineering Southern Polytechnic State University GA United States

ISBN: (纸本)9781450308571

Lesion segmentation plays an important role in medical image processing and analysis. There exist several successful dynamic programming (DP) based segmentation methods for general images. In those methods, the gradient is used as an important factor in the cost function to attract the contours to the boundaries. Since medical images have their characteristics such as low contrast, blurred edges and high noises, the gradient operator cannot work well enough to achieve a satisfactory performance for boundary detection. We define the local intra-class variance and combine it with the dynamic programming method to replace the traditional gradient operation. Experiments on synthetic and X-ray images are carried out and the results are compared with Canny and fast multilevel fuzzy edge detection (FMFED) algorithms. It is demonstrated that the proposed method performs better on medical images with low contrast, blurred edges and high noises. In addition, 483 regions of interest of mammograms randomly extracted from DDSM of the University of South Florida are used to compare our proposed method with the plane-fitting and dynamic programming method (PFDP), and the normalized cut segmentation method (Ncut). The results demonstrate that our method is more accurate and robust than PFDP and Ncut. © 2012 ACM.

关键词： Dynamic programming

来源：评论

学校读者我要写书评

暂无评论

Fast Calculation of RCS over a Broad Frequency Band Using FDM and AWE technique

Fast Calculation of RCS over a Broad Frequency Band Using FD...

引用

International Symposium on Antennas Propagation and EM Theory

作者： Tao Sheng Yufa Sun Lingyang Kong Key Lab. of Intelligent Computing & Signal Processing Ministry of Education Anhui University

ISBN: (纸本)9781467317993

The fast dipole method (FDM) in conjunction with the asymptotic waveform evaluation (AWE) technique is presented for fast calculation of radar cross section (RCS) from arbitrarily shaped perfect electric conductor targets over a broad frequency band. The FDM, which is based on the equivalent dipole-moment (EDM) method, is employed to reduce impedance matrix storage and accelerate the matrix-vector multiplications in the solutions of the Taylor coefficients. The application of AWE technique enables fast frequency sweep analysis. The numerical results show that this method greatly increased the computational efficiency without losing accuracy conditions compared with the traditional method of moments (MoM) combined with AWE technique.

关键词： Fast dipole method Equivalent dipole-moment Asymptotic waveform evaluation Radar cross section Method of moments

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：