检索结果-内蒙古大学图书馆

Plasmonic nano-rod antennas based on fast electromagnetic method

Guangzi Xuebao/Acta Photonica Sinica 2014年第3期43卷

作者： Fang, Ming Song, Kai-Hong Wang, Juan-Juan Huang, Zhi-Xiang Wu, Xian-Liang Key Laboratory of Intelligent Computing and Signal Processing Anhui University Hefei 230039 China Department of Physics and Electronic Engineering Hefei Normal University Hefei 230061 China

On the basis of the method of moments and segments sinusoidal basis functions, the impedance matrix of plasmonic nano-rod antennas can be obtained by solving the Green's function of the discretized current nodes in closed form formulations. Compared to the method of moments with different basis functions, this method can be utilized for reducing the size of matrix equations. The simulated results show that the polarization current and scattered fields can be computed accurately by employing a small-size matrix, which leads to a fast analysis for the scattering characteristic and resonant modes of nano-rod. The accuracy of the method was successfully demonstrated by comparing the simulated results with finite difference time domain technique, which is more time-consuming than the present method. Especially when dealing with the oblique incidence problem, the advantages become more apparently. The method is effective for the calculated models in this paper, and provides a fast and efficient electromagnetic analysis way for other nano-rod antennas and nanotube devices in different shapes when doing their scattering characteristics simulation.

关键词： Finite difference time domain method

来源：评论

学校读者我要写书评

暂无评论

Systematic study of finite-difference frequency-domain method for spontaneous emission in a two-dimensional environment

引用

Guangzi Xuebao/Acta Photonica Sinica 2014年第1期43卷

作者： Qi, Jian-Nan Huang, Zhi-Xiang Wang, Han-Lin Wu, Xian-Liang Chu, Jing-Yang Zhou, Li Key Laboratory of Intelligent Computing and Signal Processing Anhui University Hefei 230039 China Department of Physics and Electronic Engineering Hefei Normal University Hefei 230061 China

The improvement of the efficiency of spontaneous emission will give great help to the research and manufacture of optoelectronic devices such as single photon resource. The local density of elestromagnetic states was calculated which is represented by the electric dyadic Green's function through the finite-difference frequency-domain method, the local density of states and the spontaneous emission rate in different metal materials, structures and wavelengths were analyzed, and the intrinsic physical mechanism was explored. The results show that the spontaneous emission rate of atoms can be greatly enhanced when surface plasmon polariton couple to the emiter, and different structure and the refractive indices of materials have different improvement of spontaneous emission rate. This research can provide important reference for the manufacture and optimization of optoelectronic devices.

关键词： Spontaneous emission

来源：评论

学校读者我要写书评

暂无评论

A study on turbo code performance based on AWGN channel

A study on turbo code performance based on AWGN channel

引用

2013 International Conference on Precision Mechanical Instruments and Measurement Technology, ICPMIMT 2013

作者： Zhu, Peng Zhu, Jun Liu, Xiang Key Laboratory of Intelligent Computing and Signal Processing of Ministry of Education Anhui University No.3 Feixi Rd Hefei 230039 China

Turbo codes have a wide range of applications in 3G mobile communications, deep-sea communications, satellite communications and other power constrained fields. In the paper, the Turbo Code Decoding Principle and several major decoding methods are introduced. Simulations of Turbo code performance under different parameters of AWGN channel are made and the effects of the different interleaving length, the number of iterations, and the decoding algorithm to Turbo code performance are also discussed in AWGN channel. Simulation results show that under the same signal-to-noise ratio, the more the number of iterations is, the longer the sequence of information is, and the more excellent decoding algorithm is, the better the performance of Turbo codes is. © 2013 Trans Tech Publications Ltd, Switzerland.

关键词： Bit error rate

来源：评论

学校读者我要写书评

暂无评论

Video Summarization by Robust Low-Rank Subspace Segmentation

Advances in Intelligent Systems and Computing

引用

Advances in intelligent Systems and computing 2013年 212卷 929-937页

作者： Tu, Zhengzheng Sun, Dengdi Luo, Bin Key Lab of Intelligent Computing and Signal Processing of Ministry of Education Anhui University Hefei 230039 China School of Computer Science and Technology Anhui University Hefei 230601 China Key Lab of Industrial Image Processing and Analysis of Anhui Province Hefei 230039 China

ISBN: (纸本)9783642375019

Video summarization provides condensed and succinct representations of the content of a video stream. A static storyboard summarization approach based on robust low-rank subspace segmentation is proposed in this paper. Firstly, video frames are represented as multi-dimensional vectors, and then embedded into a group of affine subspaces using low-rank representation according to the content similarity of the frames in the same subspace. Secondly, a series of subspaces are segmented based on the Normalized Cuts algorithm. The video summary is finally generated by choosing key frames from the significant subspaces and ranking these key frames in temporal order. The experimental results demonstrate that the proposed summarization algorithm can produce crucial key frames and effectively reduce the visual content redundancy in summary comparing with the conventional approaches. © Springer-Verlag Berlin Heidelberg 2013.

关键词： Vectors

来源：评论

学校读者我要写书评

暂无评论

Remote sensing identification of shrub encroachment in grassland in Inner Mongolia

引用

Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering 2014年第11期30卷 152-158页

作者： Dong, Zhou Zhao, Xia Liang, Dong Huang, Wenjiang Peng, Dailiang Huang, Linsheng Key Laboratory of Intelligent Computing and Signal Processing Ministry of Education Anhui University Hefei 230039 China School of Electronic and Information Engineering Anhui University Hefei 230039 China Key Laboratory of Digital Earth Science Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences Beijing 100094 China State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing 100093 China

Shrub encroachment has been a wide phenomenon across the arid and semi-arid grasslands in Inner Mongolia, China. Although numerous studies have investigated the effect of this phenomenon on community composition, ecosystem structure, and nutrient cycling, reports on the distribution patterns of shrub encroachment are limited. A recent development in satellite remote sensing enables accurate assessment of shrub distribution and its dynamics at large scales. In this paper, the combined ground survey in Xianghuangqi, four satellite images (with spatial resolution of 5.8 m) of ZY-3, covering nearly the whole area and taken between July and August in 2013, were used to identify the shrub distribution in this region. It should be noted that the shrub here indicated the shrub-grass mosaic due to the mixed pixel effect, and the identification was weak when the coverage of shrub was on low levels. The NDVI threshold method was first used to extract the vegetation coverage area, and then three traditional pixel-oriented methods (Support vector machine, Maximum likelihood and Mahalanobis distance), compared with the object-oriented method, were used for the classification of images. Object-oriented method is different from the traditional one, in that the classification is not based on the spectral characteristics of individual pixel, but relies on the image object with spatial texture and shape and size characteristics. Ground survey data were used to compare the accuracy level of these methods. It indicated that the shrub recognition accuracy by using support vector machine algorithm is the highest among the three pixel-oriented methods, with higher producer accuracy and user accuracy than the other two algorithms. Furthermore, the overall classification accuracy of this algorithm is 81.15% higher than that of the maximum likelihood (73.33%) and the Mahalanobis distance (61.77%). However, the overall recognition accuracy by using the object-oriented approach (combined scale

关键词： Maximum likelihood

来源：评论

学校读者我要写书评

暂无评论

EPAS: Efficient privacy-preserving authentication scheme for VANETs-based emergency communication

Journal of Software

引用

Journal of Software 2013年第8期8卷 1914-1922页

作者： Jia, Xuedan Yuan, Xiaopeng Meng, Lixia Wang, Liangmin School of Computer Science and Telecommunication Engineering Jiangsu University Zhenjiang China School of Electronic Engineering and Optoelectronic Techniques NUST Nanjing China Key Laboratory of Intelligent Computing and Signal Processing MOE Anhui University Hefei China

Vehicular Ad Hoc Networks (VANETs) can provide participants with security services and entertainment information during the driving. To guarantee correct and smooth operations of VANETs, it is necessary to achieve efficient authentication with user privacy preserving. Current solutions either cannot satisfy privacy requirements, or are not efficient in message verification. Moreover, all the existing schemes are RSU-based. We, for the first time, apply VANETs to emergency communication during disaster rescue, and effective authentication scheme is proposed in accordance with the actual environment, where there is no fixed road-side unit (RSU). In this paper, we present an efficient identity based signature scheme EPAS, which satisfies conditional privacy requirements through software solution. In aspect of efficiency, both lightweight signature and batch verification are employed to provide effective authentication. Extensive theoretical and experimental analyses demonstrate the security and efficiency of EPAS in terms of privacy-preserving and low authentication delay. © 2013 ACADEMY PUBLISHER.

关键词： Vehicular ad hoc networks

来源：评论

学校读者我要写书评

暂无评论

Optimal Tracking Control for Ship Course Using Approximate Dynamic Programming Method

Optimal Tracking Control for Ship Course Using Approximate D...

引用

第三十二届中国控制会议

作者： XIE Qingqing LUO Bin TAN Fuxiao School of Computer Science and Technology Anhui University Key Laboratory of Intelligent Computing ＆ Signal Processing Ministry of EducationAnhui University School of Computer and Information Fuyang Teachers college

ISBN: (纸本)9781479900305

Dynamic programming(DP) is not a useful tool for solving many control problems because of its complexity in computation. In this paper,we propose Approximate Dynamic Programming(ADP) optimal control strategy for ship course trajectory tracking control *** system transformation,we convert the optimal tracking problem into designing a infinite-horizon optimal regulator for the tracking error ***-dependent Heuristic Dynamic programming(ADHDP) technique,as one form of ADR is presented to obtain the infinite-horizon optimal tracking *** the ship course optimal tracking control simulation results,we can see that the ADHDP controller makes the performance index and the control sequence for the error dynamics converge to the optimal *** BP neural networks are used as parametric structures to implement ADHDP *** two neural networks aim at approximating the cost function and the control law,respectively.

关键词： Optimal Tracking Control Approximate Dynamic Programming ADHDP Ship Course

来源：评论

学校读者我要写书评

暂无评论

Novel non-convex online algorithms for robust ranking

引用

Journal of Information and Computational Science 2013年第17期10卷 5743-5759页

作者： Cheng, Fan Wang, Xufa Key Laboratory of Intelligent Computing and Signal Processing Ministry of Education Anhui University Hefei 230039 China School of Computer Anhui University Hefei 230039 China School of Computer University of Science and Technology of China Hefei 230027 China

Recently increasing attention has been focused on learning to rank, which aims to learn a ranking function from a set of training data with relevance labels. Many of the ranking algorithms are based on the pairwise preference framework. However, one disadvantage of pairwise ranking is that it is sensitive to the outliers. To tackle the problem, in this paper, we propose two novel online algorithms based on non-convex Ramp Loss which can suppress the influence of outliers. The first one directly defines a new objective function based on Ramp Loss. Considering that the objective function is non-convex, we use the Concave-convex Procedure (CCCP) for convex approximation, then design an online algorithm based on Dual Coordinate Descend Method to learn the final ranking model. The second algorithm applies selective sampling technology in the training phase. It ignores the instances that lie in the flat region of the Ramp Loss in advance, before they are processed by the learner. Experimental results show that the algorithms we proposed have significant robustness to outliers and yield better generalization performance than the baseline rankers, and the results also prove that our algorithms have less computational running time for their less support vectors. © 2013 Binary Information Press.

关键词： Approximation algorithms

来源：评论

学校读者我要写书评

暂无评论

Image bag generator based on bag of visual words

引用

Journal of Information and Computational Science 2013年第5期10卷 1453-1462页

作者： Zhao, Shu Xu, Chao Xu, Xiansheng Xu, Chenchu Zhang, Yanping Ye, Hong School of Computer Science and Technology Anhui University Hefei 230039 China Key Laboratory of Intelligent Computing and Signal Processing of Ministry of Education Anhui University Hefei 230039 China Insurance Office Anhui Provincial Hospital Hefei 230001 China

Multi-instance learning is a good tool to deal with the ambiguity of image in Content-based Image Retrieval (CBIR). According to some researchers' work, image bag generator which transforms an image into an instance bag plays an important role in applying multi-instance learning for CBIR. In this paper, the bag generator based on bag of visual words, named Vdbag, is proposed. First, it extracts local features of image from all images, and then it obtains a set of visual words called visual vocabulary by clustering local features where each local cluster's center is a visual word. Our work mainly includes (1) We introduce bag of visual words into image bag generator. (2) We give a reasonable description to express the instance in an image bag. We add the frequency of each visual word as the last dimension of this visual word to construct the corresponding instance. Experimental results with Corel image database show that the proposed method could achieve better precision than that of some existing bag generators. © 2013 Binary Information Press.

关键词： Content based retrieval

来源：评论

学校读者我要写书评

暂无评论

Method for convergent projective non-negative matrix factorization

引用

Journal of Information and Computational Science 2013年第6期10卷 1847-1854页

作者： Hu, Lirui Wu, Jianguo Wang, Lei Key Laboratory of Intelligent Computing and Signal Processing of Ministry of Education Anhui University Hefei 230039 China School of Computer Science and Technology Nantong University Nantong 226019 China School of Computer Science and Technology Anhui University Hefei 230039 China

In order to solve the problem of algorithm convergence in Projective Non-negative Matrix Factorization (P-NMF), a method, called Convergent Projective Non-negative Matrix Factorization (CP-NMF), is proposed. In CP-NMF, an objective function of Frobenius norm is defined. The Taylor series expansion and the Newton iteration formula of solving root are used. An iterative algorithm for basis matrix is derived, and a proof of algorithm convergence is provided. Experimental results show that the convergence speed of the algorithm is higher, however it is affected by the initial value of the basis matrix;relative to Non-negative Matrix Factorization (NMF), the orthogonality and the sparseness of the basis matrix are better, however the reconstructed results of data show that the basis matrix is still approximately orthogonal;in face recognition, there is higher recognition accuracy. The method for CP-NMF is effective. Copyright © 2013 Binary Information Press.

关键词： Face recognition

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：