检索结果-内蒙古大学图书馆

Calibration method of 3-D profile measurement by grating projection

Journal of Hunan University of Science and Technology 2006年第2期21卷 40-43页

作者： Huang, Meng-Tao Guo, Ying-Fu Jiang, Zhuang-De Tian, Ai-Ling Li, Bing State Key Lab. for Manufacturing Systems Engineering Institute of Precise Engineering Xi'an Jiaotong University Xi'an 710049 China Institute of Electrical and Control Engineering Xi'an University of Science and Technology Xi'an 710054 China

Aiming at the problem of inferior precision and bad maneuverability during system calibration of the conventional system construction, In this paper, a new system construction of three-dimension profile measurement was presented. Because of without parallel and perpendicular restricted condition in this system, the CCD camera and the projecting device could be located arbitrarily. By importing the camera calibration technique and the lens distortion is considered of the CCD camera, the new system has better maneuverability and higher accuracy than conventional method.

关键词： Grating projection Parameter calibration Profile measurement

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Improved simultaneous extrapolation in sharp impulse signals in time and frequency domains

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical engineering 2006年第18期26卷 133-137页

作者： Zou, Jun Guo, Jian He, Jin-Liang Zhang, Bo Teng, Wen-Rui State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing 100084 China Dept. of Electrical Engineering Henan University of Technology Zhengzhou 450042 China

The characteristic of the transient response of the grounding system takes on a fast rising and slow damping with the lightning excitation. An improved simultaneous time and frequency domain extrapolation method is presented based on Hermite function expansion, which takes the above mentioned characteristic of the transient signal into account, using early time response and low-frequency data, the complete electromagnetic response is generated. By using mutually complementary data, simultaneous extrapolation in time and frequency domains are carried out by using the Hermite polynomials as the basis function. However, the extrapolation method is not suitable to deal with the transient response with the fast pulse excitation. The improvement for the extrapolation method is to pre- and post-process the transient response data with the fast pulse excitation. As a pre-processed procedure, in order to reduce the condition number of the matrix used for determined the coefficient of basis function, the scale transformation is used in time and frequency domain respectively, and the data in time domain is smoothed and padded with zero. An adaptive algorithm to determine the order of Hermite function is also proposed. As a post-processed step, the transient data are smoothed by using GPOF to obtain a convergent result. The numerical example and the field measurement are presented to illustrate the application of this methodology. The method proposed enhances the ability of the simultaneous time and frequency extrapolation techniques.

关键词： Signal processing

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Adaptive Galerkin approach of the indirect boundary element method for calculating 3D linear magnetostatic field

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical engineering 2006年第1期26卷 96-100页

作者： Zou, Jun He, Jin-Liang Yu, Hai-Yu Teng, Wen-Rui State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing 100084 China Dept. of Electrical Engineering Henan University of Technology Zhengzhou 450042 China

The indirect boundary element method has some special advantages for the 3D linear magnetostatic field calculation by using the equivalent magnetic surface charge. In order to improve the accuracy of solutions and decrease the computational costs, an adaptive Galerkin approach to solve the magnetostatic integral equation is presented by using the h-type refinement technology. The basic idea of the proposed approach can be summarized as follows. The error of magnetic flux density is globally minimized in the Galerkin sense in the implementation, so the continuity error of magnetic flux density of each element can be served as a criterion to guide the adaptive refinement. The singularity of geometric corners and edges can be overcome due to the scheme of the discretization of the integral equation with Galerkin's approach. In addition, a local resolution technology is proposed, which leads to the minimal refined unknown. The numerical examples show the proposed method is efficient and accurate by comparison to the analytical solutions and the measured results.

关键词： Magnetic fields

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Irregular low-density convolutional codes

Irregular low-density convolutional codes

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作者： Ma, Linhua Liu, Jun Chang, Yilin State Key Lab. of Integrated Service Networks Xidian University Xi'an China KongJun Engineering Institute Xi'an China Xi'an Satellite Control Center Xi'an China

A method for constructing low-density convolutional (LDC) codes with the degree distribution optimized for block low-density parity-check (LDPC) codes is presented. If the degree distribution is irregular, the constructed LDC codes are also irregular. In this letter we give the encoding and decoding method for LDC codes, and study how to avoid the short cycles of LDC codes. Some simulation results are also presented. Copyright © 2005 The Institute of Electronics, Information and Communication Engineers.

关键词： Codes (symbols)

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Mechanical properties and oxidation behavior of Si3N 4/BN laminated ceramics

Mechanical properties and oxidation behavior of Si3N 4/BN la...

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作者： Li, Cuiwei Wang, Chang-An Huang, Yong School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing 100044 China State Key Lab. of New Ceramics and Fine Processing Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

Laminated ceramics with high mechanical properties were fabricated in the Si3N4/BN system. The mechanical properties at elevated temperatures were tested, and the oxidation behavior during tested procedure was studied at the same time. The flexure strength of the Si3N 4/BN laminated ceramics changed a little below 1000°C. The displacement-load curves appeared non-linear characteristic even at high temperature. During testing procedure at high temperature, oxidation behavior of silicon nitride and silicon carbide happened, and no oxidation product of boron nitride was found. The silicon nitride layers were oxidized to form a protective silicate scale, which prevented oxidation of the boron nitride interlayers. The stability of boron nitride was beneficial to the boron nitride interlayer to partition the silicon nitride matrix layers at high temperature.

关键词： Ceramic materials

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Static output feedback H∞ controller design for fuzzy systems subject to sensor nonlinearities

Static output feedback H∞ controller design for fuzzy syste...

引用

2004 IEEE International Conference on Systems, Man and Cybernetics, SMC 2004

作者： Yuan, Xiao-Hu Lu, Bin He, Youjin Sun, Fu-Chun Dept. of Control Engineering Nav. Aero. Engineering Academy Yantai Shandong Province China State Key Lab. Intelligent T./S. Tsinghua University Beijing China

In this paper, we consider the design of static output feedback H∞ controller for Takagi-Sugeno fuzzy systems subject to sensor nonlinearities. The control problem is reduced to a feasibility problem of bilinear matr... 详细信息

ISBN: (纸本)0780385667

关键词： Fuzzy control

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Synthesis of H2 guaranteed cost fuzzy controller for missile altitude system via linear matrix inequalities

Synthesis of H2 guaranteed cost fuzzy controller for missile...

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2004 IEEE International Conference on Systems, Man and Cybernetics, SMC 2004

作者： Yuan, Xiao-Hu Ren, Jian-Cun He, You-Jin Sun, Fu-Chun Dept. of Control Engineering Nav. Aero. Engineering Academy Yantai Shandong province China State Key Lab. Intelligent T. Dept. of Comp. Sci. and Technolgy Tsinghua University Beijing China

ISBN: (纸本)0780385667

This paper deals with H2 guaranteed cost (GC) fuzzy output feedback control problem for missile altitude control system. First, the Takagi-Sugeno fuzzy model is employed to represent the dynamics of the missile altitude control system. Next, we present necessary and sufficient conditions for the existence of a quadratically stabilizing fuzzy output feedback controller which also assure H2 guaranteed cost performance on a fuzzy dynamic system where the uncertainty is of the norm bounded type. The conditions are presented as a collection of linear matrix inequalities. A simulation on the missile altitude system is given to illustrate the effectiveness of the proposed design method. © 2004 IEEE.

关键词： control equipment

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Synthesis of H/sub 2/ guaranteed cost fuzzy controller for missile altitude system via linear matrix inequalities

Synthesis of H/sub 2/ guaranteed cost fuzzy controller for m...

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IEEE International Conference on Systems, Man and Cybernetics

作者： Xiao-Hu Yuan Jian-Cun Ren You-Jin He Fu-Chun Sun Dept. of Control Engineering Naval Aeronautical Engineering Academy Yantai Shandong province China State Key Lab. of Intelligent Technology and Systems Tsinghua University Beijing China

ISBN: (纸本)0780385675

This paper deals with H/sub 2/ guaranteed cost (GC) fuzzy output feedback control problem for missile altitude control system. First, the Takagi-Sugeno fuzzy model is employed to represent the dynamics of the missile altitude control system. Next, we present necessary and sufficient conditions for the existence of a quadratically stabilizing fuzzy output feedback controller which also assure H/sub 2/ guaranteed cost performance on a fuzzy dynamic system where the uncertainty is of the norm bounded type. The conditions are presented as a collection of linear matrix inequalities. A simulation on the missile altitude system is given to illustrate the effectiveness of the proposed design method.

关键词： Fuzzy control Fuzzy systems control systems Missiles control system synthesis Costs Output feedback Takagi-Sugeno model Sufficient conditions Uncertainty

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Morphological characterization of Cu-W thin films based on wavelet transform

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Zhenkong Kexue yu Jishu Xuebao/Vacuum Science and Technology 2004年第SUPPL.期24卷 14-16+37页

作者： Wang, Yuan Bai, Xuanyu Xu, Kewei Fan, Duowang State-Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong University Xi'an 710049 China Department of Mechanical Engineering Lanzhou Railway Institute Lanzhou 730070 China Lab. of Opto-Electronic Technology and Intelligent Control Lanzhou Jiaotong University Lanzhou 730070 China

The evolution of surface morphology of Cu-W thin films with deposition time on silicon wafers was studied by discrete wavelet transform (DWT). A strategy based on wavelet transform to describe surface morphology of thin films was presented. The results showed that the surface morphology of thin films was unstable until the sputtering time exceeds 10 min. The surface morphology variations of different thin films could be distinguished primarily by high frequency signals.

关键词： Thin films

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Application of a genetic algorithm in triangulation of a 3-D object surface

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International Journal of Computers and Applications 2000年第2期22卷 73-77页

作者： Zhenyu, Chen Mbede, J.B. Yan, Zhou Dehua, Li Hanping, Hu State Commn. Res. Open Lab. Image P. Inst. Pattern Recog. Artif. Intell. Huazhong Univ. of Sci. and Technol. 430074 Wuhan China Intelligent Contr. and Robotics Lab. Dept. of Contr. Sci. and Engineering Huazhong Univ. of Sci. and Technol. 430074 Wuhan China Second Artillery Institute Huazhong Univ. of Sci. and Technol. Inst. Pattern Recog. Artif. Intell. Huazhong Univ. of Sci. and Technol. Second Artillery Institute China Wuhan University China Artificial Intelligence Department University of Edinburgh Inst. of AI and Pattern Recognition Huazhong Univ. of Sci. and Technol. China Cogn. Sci. Natl. Key Found. Res. P. Douala University Cameroon Tübingen University Germany Automatic Control Laboratory Darmstadt University Department of Service Cameroon Min. of National Education Robotics Laboratory Huazhong Univ. of Sci. and Technol. Wuhan China Assoc. Connectionnistes These-ACTH Rennes France IEEE Soc. of Robotics and Automation IEEE Society of Control Systems IASTED Assoc. Jeunes Chercheurs Robotique France Navy University of Engineering China Huazhong Univ. of Sci. and Technol. China Department of Computer Science Airforce Radar Acad. of Engineering China Inst. of P.R and AI Huazhong Univ. of Sci. and Technol.

This paper proposes a genetic-based algorithm for surface reconstruction of three-dimension (3-D) objects from a group of contours representing its section plane lines. The algorithm can optimize the triangulation of the surface of 3-D objects with a multi-objective optimization function to meet the needs of a wide range of applications. Further, a new crossover operator for triangulation and a new 3-D quadrilateral mutation operator are also introduced.

关键词： Object recognition

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