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Design of ontology mapping framework and improvement of similarity computation

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Journal of Systems Engineering and Electronics 2007年第3期18卷 641-645页

作者： Zheng Liping Li Guangyao Liang Yongquan Sha Jing coll. of Electron and information Engineering Tongji Univ Shanghai 201804 P. R. China coll. of information science and Engineering Shandong Univ. of Science and Technology Qingdao 266510 P. R China

Ontology heterogeneity is the primary obstacle for interoperation of ontologies. Ontology mapping is the best way to solve this problem. The key of ontology mapping is the similarity computation. At present, the method of similarity computation is imperfect. And the computation quantity is high. To solve these problems, an ontology-mapping framework with a kind of hybrid architecture is put forward, with an improvement in the method of similarity computation. Different areas have different local ontologies. Two ontologies are taken as examples, to explain the specific mapping framework and improved method of similarity computation. These two ontologies are about classes and teachers in a university. The experimental results show that using this framework and improved method can increase the accuracy of computation to a certain extent. Otherwise, the quantity of computation can be decreased.

关键词： ontology ontology heterogeneity ontology mapping wordnet similarity computation.

Empirical data decomposition and its applications in image compression

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Journal of Systems Engineering and Electronics 2007年第1期18卷 164-170页

作者： Deng Jiaxian Wu Xiaoqin information science and Technology coll. Hainan Univ. Haikou 570228 E R. China Electric information Engineering coll. Beijing Jiaotong Univ. Beijing 100044 P. R. China

A nonlinear data analysis algorithm, namely empirical data decomposition （EDD） is proposed, which can perform adaptive analysis of observed data. Analysis filter, which is not a linear constant coefficient filter, is automatically determined by observed data, and is able to implement multi-resolution analysis as wavelet transform. The algorithm is suitable for analyzing non-stationary data and can effectively wipe off the relevance of observed data. Then through discussing the applications of EDD in image compression, the paper presents a 2-dimension data decomposition framework and makes some modifications of contexts used by Embedded Block Coding with Optimized Truncation （EBCOT） . Simulation results show that EDD is more suitable for non-stationary image data compression.

关键词： Image processing Image compression Empirical data decomposition Non-stationary Nonlinear Data decomposition framework

Implementation of LT codes based on chaos

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Chinese Physics B 2008年第10期17卷 3609-3615页

作者：周茜李亮陈增强赵加祥 coll.ge of information technical science Nankai University

Fountain codes provide an efficient way to transfer information over erasure channels like the Internet. LT codes are the first codes fully realizing the digital fountain concept. They are asymptotically optimal rateless erasure codes with highly efficient encoding and decoding algorithms. In theory, for each encoding symbol of LT codes, its degree is randomly chosen according to a predetermined degree distribution, and its neighbours used to generate that encoding symbol are chosen uniformly at random. Practical implementation of LT codes usually realizes the randomness through pseudo-randomness number generator like linear congruential method. This paper applies the pseudo-randomness of chaotic sequence in the implementation of LT codes. Two Kent chaotic maps are used to determine the degree and neighbour（s） of each encoding symbol. It is shown that the implemented LT codes based on chaos perform better than the LT codes implemented by the traditional pseudo-randomness number generator.

关键词： digital fountain fountain codes LT codes Kent chaotic map

Design of complex FIR filters with arbitrary magnitude and group delay responses

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Journal of Systems Engineering and Electronics 2009年第5期20卷 942-947页

作者： Wang Xiaohua He Yigang Electrical and information Engineering coll. Changsha Univ. of Science & Technology Changsha 410077 P. R. China Electrical and information Engineering coll. Hunan Univ. Changsha 410082 P. R. China

To design approximately linear-phase complex coefficient finite impulse response （FIR） digital filters with arbitrary magnitude and group delay responses, a novel neural network approach is studied. The approach is based on a batch back-propagation neural network algorithm by directly minimizing the real magnitude error and phase error from the linear-phase to obtain the filter＇s coefficients. The approach can deal with both the real and complex coefficient FIR digital filters design problems. The main advantage of the proposed design method is the significant reduction in the group delay error. The effectiveness of the proposed method is illustrated with two optimal design examples.

关键词： signal processing digital filter neural network complex coefficient filter optimal design finite impulse response.

Universal construction of control Lyapunov functions for a class of nonlinear systems

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Journal of Systems Engineering and Electronics 2007年第3期18卷 598-602页

作者： Cai Xiushan Wang Xiaodong Zhang Haoran coll. of information science and Engineering Zhejiang Normal Univ Jinhua 321004 P. R. China

A method is developed by which control Lyapunov functions of a class of nonlinear systems can be constructed systematically. Based on the control Lyapunov function, a feedback control is obtained to stabilize the closed-loop system. In addition, this method is applied to stabilize the Benchmark system. A simulation shows the effectiveness of the method.

关键词： control Lyapunov functions nonlinear systems stabilization.

Optimum selection of common master image for ground deformation monitoring based on PS-DInSAR technique

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Journal of Systems Engineering and Electronics 2009年第6期20卷 1213-1220页

作者： Zhu Zhengwei Zhou Jianjiang coll. of information science and Technology Nanjing Univ. of Aeronautics School of information Engineering Southwest Univ. of Science and Technology Mianyang 621010 P. R. China

Considering the joint effects of various factors such as temporal baseline, spatial baseline, thermal noise, the difference of Doppler centroid frequency and the error of data processing on the interference correlation, an optimum selection method of common master images for ground deformation monitoring based on the permanent scatterer and differential SAR interferometry （PS-DInSAR） technique is proposed, in which the joint correlation coeficient is used as the evaluation function. The principle and realization method of PS-DInSAR technology is introduced, the factors affecting the DInSAR correlation are analysed, and the joint correlation function model and its solution are presented. Finally an experiment for the optimum selection of common master images is performed by using 25 SAR images over Shanghai taken by the ERS-1/2 as test data. The results indicate that the optimum selection method for PS-DInSAR common master images is effective and reliable.

关键词： remote sensing ground deformation monitoring differential SAR interferometry common master image permanent scatterer synthetic aperture radar image analysis.

Improved scheme with cooperative diversity based on distributed space-time block coding

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Journal of Systems Engineering and Electronics 2009年第3期20卷 463-469页

作者： Du Na Xu Dazhuan coll. of information science & Technology Nanjing Univ. of Aeronautics and Astronautics Nanjing 210016 P. R. China

An improved scheme with cooperative diversity based on distributed space-time block coding （WCD- DSTBC） is proposed, which effectively achieves diversity gains and improves the performance of the system by sharing some single-antenna users＇ antennas to form a virtual antenna array and combining with distributed spacetime block coding （DSTBC） mode. Then the relation between the system BER and the interuser BER for WCDDSTBC scheme is theoretically derived and the closed-form expression of BER for WCD-DSTBC system is obtained. The simulation results show that the proposed WCD-DSTBC scheme achieves distinct gains over the non-cooperative multi-carrier CDMA （MC-CDMA） system. When system BER is le-3 and interuser BER is le-3, about 2.5 dB gain can be gotten. When interuser channel state information （CSI） outgoes the users＇ individual CSI, about 3 dB gain is also achieved.

关键词： multiple input multiple output cooperative diversity distributed space-time block coding multicarrier CDMA.

A new model analysis of the third harmonic voltage in inductive measurement for critical current density of superconducting films＊

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Chinese Physics B 2011年第2期20卷 471-477页

作者： Zhang Xu Wu Zhi-Zhen Zhou Tie-Ge He Ming Zhao Xin-Jie Yan Shao-Lin Fang Lan Department of Electronic information science and Technology College of Information Technical Science Nankai University Tianjin 300071 China

The critical current density Jc is one of the most important parameters of high temperature superconducting films in superconducting applications, such as superconducting filter and superconducting Josephson devices. This paper presents a new model to describe inhomogeneous current distribution throughout the thickness of superconducting films applying magnetic field by solving the differential equation derived from Maxwell equation and the second London equation. Using this model, it accurately calculates the inductive third-harmonic voltage when the film applying magnetic field with the inductive measurement for Jc. The theoretic curve is consistent with the experimental results about measuring superconducting film, especially when the third-harmonic voltage just exceeds zero. The Jc value of superconducting films determined by the inductive method is also compared with results raeasured by four-probe transport method. The agreements between inductive method and transport method are very good.

关键词： inhomogeneous current third-harmonic voltage critical current density magnetic field

Application of neural networks for permanent magnet synchronous motor direct torque control

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Journal of Systems Engineering and Electronics 2008年第3期19卷 555-561页

作者： Zhang Chunmei Liu Heping Chen Shujin Wang Fangjun information Engineering School Univ. of Science and Technology Beijing Beijing 100083 China Engineering Dept. Coll. of Electron Science and Technology Career Beijing 100029 China

Neural networks require a lot of training to understand the model of a plant or a process. Issues such as learning speed, stability, and weight convergence remain as areas of research and comparison of many training algorithms. The application of neural networks to control interior permanent magnet synchronous motor using direct torque control （DTC） is discussed. A neural network is used to emulate the state selector of the DTC. The neural networks used are the back-propagation and radial basis function. To reduce the training patterns and increase the execution speed of the training process, the inputs of switching table are converted to digital signals, i.e., one bit represent the flux error, one bit the torque error, and three bits the region of stator flux. Computer simulations of the motor and neural-network system using the two approaches are presented and compared. Discussions about the back-propagation and radial basis function as the most promising training techniques are presented, giving its advantages and disadvantages. The system using back-propagation and radial basis function networks controller has quick parallel speed and high torque response.

关键词： interior permanent magnet synchronous motor radial basis function neural network torque control,direct torque control.