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An effective and practical method for solving an unnegligible problem inherent in the current calculation model for multi-support seismic analysis of structures

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Science china.Technological Sciences) 2010年第7期53卷 1774-1784页

作者： LIU GuoHuan2. GUO Wei1 & LI HongNan2.1 National engineering Laboratory for High Speed Railway Construction, School of Civil engineering and Architecture, Central South University, Changsha 410075, {2.2.Faculty of Infrastructure engineering, Dalian University of Technology, Dalian 11602., china Faculty of Infrastructure engineering Dalian University of Technology Dalian China National engineering Laboratory for High Speed Railway Construction School of Civil Engineering and Architecture Central South University Changsha China

In the seismic analysis of extended structures subject to spatially varying motions, the displacement input model instead of acceleration model is usually adopted for accurate results. In this paper, a more detailed and comprehensive analysis of the displacement input model is carried out and the research shows that there exists an unnegligible problem in the current displacement model, which leads to the irrationality and unconvergence of some calculated results such as base shear etc. Based on the situation, an effective method named massless rigid element (MRE) method is presented to solve the problem. Moreover, the rationality and accuracy of the method are further assessed and the method is applied to a transmission tower-line system project using the commercially available structural analysis software SAP2.00. The theoretical and numerical analyses indicate that the MRE approach is not only feasible with sufficient computational accuracy but also practical and can be easily implemented using the commercially available finite element software such as SAP2.00.

关键词： extended structures seismic responses spatially varying motions displacement input model massless rigid element (MRE) transmission tower-line system

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On the placement of actuators and sensors for flexible structures with closely spaced modes

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Science china.Technological Sciences) 2010年第7期53卷 1973-1982页

作者： LIU XiaoXiang1,2.& HU Jun1,2.1 Beijing Institute of Control engineering, Beijing 100190, china.2.State Key Laboratory of Science and Technology on Space Intelligent Control, Beijing 100190, {2. Beijing Institute of Control engineering Beijing China State Key Laboratory of Science and Technology on Space Intelligent Control Beijing China

This paper analyzed the fundamental limitations of previous work and developed a new method to optimally locate actuators and sensors for structures with close modes. Optimization criteria were defined based on the distinguishing modal controllability and observability measures of close modes. An appropriate genetic algorism was adopted as the optimization algorism. Solving the high order Lyapunov functions was avoided by means of the closed-form expressions for controllability and observability Grammians. Since structure with widely separated natural frequencies is approximately balanced, computational efficiency was improved by grouping close modes together and dealing with the resulting subsystems independently. Finally, the effectiveness and optimality of the novel placement scheme were verified on a model structure with close modes.

关键词： close modes controllability/observability sensor/actuator optimization criterion optimization algorithm

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Truncation error calculation based on Richardson extrapolation for variable-step collaborative simulation

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Science china.Information Sciences) 2011年第6期54卷 1238-1250页

作者： ZHANG HeMing 1 , LIANG SiLu 2., SONG ShiJi 1 & WANG HongWei 3 1 Department of Automation, TNList, Tsinghua University, Beijing 100084, china.2.Computer and Information Management Center, Tsinghua University Beijing 100084, china.3 {2. Design centre, {2. Department, Cambridge University, Cambridge CB2.1PZ, UK Department of Automation TNList Tsinghua University Beijing China Computer and Information Management Center Tsinghua University Beijing China engineering Design centre Engineering Department Cambridge University Cambridge UK

Collaborative simulation is an effective approach to performing simulation analysis for complex systems by integrating models developed for different engineering disciplines. Collaborative simulation issues include the modeling of coupled multidisciplinary systems, and the simulation running time integration of these models that are solved parallelly. Estimation of the local truncation error of coupling models is the key to solve multidisciplinary collaborative simulation problem, which is actually used to restrict the simulation step. This paper presents a variable-step method based on Richardson extrapolation for calculating the local truncation error to solve collaborative simulation problem of multidisciplinary coupling models. Formulas for estimating the local truncation error are derived through theoretical analysis by using integration methods and interpolation technologies, respectively. The simulation experiments are illustrated to validate the accuracy and efficiency of proposed collaborative simulation algorithm in comparison with the usual combinative algorithm.

关键词： multidisciplinary systems collaborative simulation variable-step algorithm error estimation

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A self-calibration algorithm for cross array in the presence of mutual coupling

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Science china.Information Sciences) 2011年第4期54卷 836-848页

作者： HU XiaoQin 1,2.CHEN Hui 2.WANG YongLiang 2.& CHEN JianWen 2.1 College of Electronic Science and engineering,National University of Defense Technology,Changsha 410073,china.2.Key Lab of Wuhan Radar Academy,Wuhan 430019,{2. College of Electronic Science and engineering National University of Defense Technology Changsha China Key Lab of Wuhan Radar Academy Wuhan China

In this paper,a novel blind mutual coupling self-calibration algorithm especially tailored to cross array is *** method compensates for the mutual coupling not only between sensors in each subarray but also between two *** the property of coupling matrix,the proposed method requires neither the calibration sources in known locations nor the multidimensional nonlinear *** method can jointly estimate the DOAs of the incoming signals and the unknown mutual coupling coefficients,and has high estimation precision and low computational *** analysis and computer simulations show the effectiveness of the proposed algorithm.

关键词： cross array mutual coupling self-calibration DOA estimation

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A Sound Quality Objective Evaluation Method Based on Auditory Peripheral Simulation Model

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Journal of Bionic engineering 2010年第2期7卷 199-208页

作者： Yinhan Gao~1,Jun Xie~2.Jie Liang~1,Xin Chang~3,Baojun Wu~2.1.Experimental centre of Testing Science,Jilin University,Changchun 13002.,P.R.china.2.College of Instrumentation & Electrical {2.,Jilin University,Changchun 130061,P.R.china.3.Laboratory of Applications and Computations in Electromagnetics and Optics,Department of Electrical {2., University of Washington,WA 98195-2.00,USA Experimental centre of Testing Science Jilin University Changchun P. R. China College of Instrumentation & Electrical engineering Jilin University Changchun P. R. China Laboratory of Applications and Computations in Electromagnetics and Optics Department of Electrical Engineering University of Washington Seattle USA

Based on auditory peripheral simulation model, a new Sound Quality Objective Evaluation (SQOE) method is presented,which can be used to model and analyze the impacts of head, shoulder and other parts of human body on sound wave *** method employs the artificial head technique, in which the head related transfer function was taken into account tothe outer ear simulation ***, a bionic artificial head was designed as the outer ear model with considering the outersound field in view of theory and physical *** the auditory peripheral simulation model was built, which mimicsthe physiological functions of the human hearing, simulating the acoustic signal transfer process and conversion mechanismsfrom the free field to the peripheral auditory ***, performance comparison was made between the proposed SQOEmethod and ArtemiS software, and the verifications of subjective and objective related analysis were *** show thatthe proposed method was economical, simple, and with good evaluation quality.

关键词： sound quality objective evaluation auditory peripheral simulation model artificial head head related transfer function

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Wetting Behaviours of a Single Droplet on Biomimetic Micro Structured Surfaces

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Journal of Bionic engineering 2010年第2期7卷 191-198页

作者： Y.Q.Zu~1,Y.Y.Yan~1,J.Q.Li~2.Z.W.Han~2.1.Faculty of engineering,University of Nottingham,Nottingham NG7 2.D,UK 2.Key Laboratory of Bionic engineering (Ministry of Education,{2.,Jilin University,Changchun 13002.,P.R.china Faculty of engineering University of Nottingham Nottingham UK Key Laboratory of Bionic engineering (Ministry of Education China) Jilin University Changchun P. R. China

Natural surfaces with super hydrophobic properties often have micro or hierarchical *** this paper, the wettingbehaviours of a single droplet on biomimetic micro structured surfaces with different roughness parameters are *** model is proposed to study wetting *** results of theoretical analysis are compared with those of experimentindicating that the proposed model can effectively predict the wetting ***, a numerical simulationbased on the meso scale Lattice Boltzmann Method （LBM） is performed to study dynamic contact angles, contact lines, andlocal velocity fields for the case that a droplet displays on the micro structured surface.A spherical water droplet with r= 15 μmfalls down to a biomimetic square-post patterned surface under the force of gravity with an initial velocity of 0.01 m·sand aninitial vertical distance of 2. μm from droplet centre to the top of *** spite of a higher initial velocity, the droplet can stillstay in a Cassie state; moreover, it reaches an equilibrium state at t≈17.5 ms, when contact angle is 153.16° which is slightlylower than the prediction of Cassie-Baxter’s equation which gives θ=154.40°.

关键词： biomimetic wetting behaviours roughness surfaces contact angle wetting transition

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Economical cascadic multigrid method (ECMG)

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Science china.Mathematics 2007年第12期50卷 1765-1780页

作者： Zhong-ci SHI~1 Xue-jun XU~(1+) Yun-qing HUANG~2.~1 LSEC,Institute of computational Mathematics,Academy of Mathematics and Systems Science,Chinese Academy of Sciences,Beijing 100080,china.~2.Hunan Key Laboratory for Computation and Simulation in Science and {2.,Institute for computational and Applied Mathematics,Xiangtan University,Xiangtan 411105,china LSEC Institute of Computational Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China Hunan Key Laboratory for Computation and Simulation in Science and engineering Institute for Computational and Applied Mathematics Xiangtan University Xiangtan China

In this paper, an economical cascadic multigrid method is proposed. Compared with the usual cascadic multigrid method developed by Bornemann and Deuflhard, the new one requires less iterations on each level, especially on the coarser grids. Many operations can be saved in the new cascadic multigrid algorithms. The main ingredient is the control of the iteration numbers on the each level to preserve the accuracy without over iterations. The theoretical justification is based on the observations that the error reduction rate of an iteration scheme in terms of the smoothing property is no longer accurate while the iteration number is big enough. A new formulae of the error reduction rate is employed in our new algorithm. Numerical experiments are reported to support our theory.

关键词： economical cascadic multigrid method (ECMG), cascadic multigrid method (CMG)

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Microstructure characterization of high-energy product Nd-Fe-B thin film

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Progress in Natural Science:Materials International 2010年第1期20卷 76-80页

作者： Fang XU~1,Fang YANG~2.Xian-ping DONG~1,Lan-ting ZHANG~1,Wei LIU~2.Zhi-dong ZHANG~2.1.School of Materials Science and engineering,Shanghai Jiao Tong University,Shanghai 2.02.0,china.2.Shenyang National Laboratory for Materials Science,Institute of Metal Research and International {2. for Materials Physics,Chinese Academy of Sciences,Shenyang 110016,china School of Materials Science and engineering Shanghai Jiao Tong University Shanghai 200240 China Shenyang National Laboratory for Materials Science Institute of Metal Research and International Centre for Materials Physics Chinese Academy of Sciences Shenyang 110016 China

A Si/Mo（50 nm）/Nd-Fe-B（400 nm）/Mo（50 nm）film with relatively high-energy product（BH）max=2.7 kJ/m3)was prepared on a Si substrate heated at 650℃.The microstructure of the film was investigated by X-ray diffractometry（XRD）and high-resolution transmission electron microscopy（HRTEM）.The Nd-Fe-B thin film shows a notable out-of-plane c-axis *** （110）orientated Mo grains is proved to promote the growth of c-axis oriented texture of the Nd2.e14B grains,which is favorable to achieve a high ***-scale spherical Nd-O phases composed of randomly orientated polycrystalline grains and a sharp grain boundary without grain boundary phase between two Nd2.e14B grains are *** coercivity highly depends on a certain amount of Nd-O phase and interface morphology.

关键词： Nd-Fe-B thin films microstructure Nd-O phase magnetic properties

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Immigrant schemes for evolutionary algorithms in dynamic environments: Adapting the replacement rate

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Science china.Information Sciences) 2011年第7期54卷 1352-1364页

作者： YU Xin 1,TANG Ke 1 & YAO Xin 1,2.1 Nature Inspired Computation and Applications Laboratory,School of Computer Science and Technology,University of Science and Technology of china.Hefei 2.002.,china.2.{2. of Excellence for Research in computational Intelligence and Applications,School of Computer Science,University of Birmingham,Edgbaston,Birmingham B15 2.T,U.K. Nature Inspired Computation and Applications Laboratory School of Computer Science and Technology University of Science and Technology of China Hefei China centre of Excellence for Research in computational Intelligence and Applications School of Computer Science University of Birmingham Edgbaston Birmingham UK

One approach for evolutionary algorithms (EAs) to address dynamic optimization problems (DOPs) is to maintain diversity of the population via introducing *** far all immigrant schemes developed for EAs have used fixed replacement *** paper examines the impact of the replacement rate on the performance of EAs with immigrant schemes in dynamic environments,and proposes a self-adaptive mechanism for EAs with immigrant schemes to address *** experimental study showed that the new approach could avoid the tedious work of fine-tuning the parameter and outperformed other immigrant schemes using a fixed replacement rate with traditionally suggested values in most cases.

关键词： evolutionary algorithm dynamic optimization problem immigrant scheme self-adaptive replace- ment rate

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Extended multivariate public key cryptosystems with secure encryption function

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Science china.Information Sciences) 2011年第6期54卷 1161-1171页

作者： WANG HouZhen 1,2., ZHANG HuanGuo 1,2., WANG ZhangYi 1,2.& TANG Ming 1,2.1 The Key Laboratory of Aerospace Information Security and Trusted Computing, Ministry of Education, School of Computer, Wuhan University, Wuhan 430079, china.2.State Key Laboratory of Software engineering, Wuhan University, Wuhan 430072. {2. The Key Laboratory of Aerospace Information Security and Trusted Computing Ministry of Education School of Computer Wuhan University Wuhan China State Key Laboratory of Software engineering Wuhan University Wuhan China

Advances in quantum computers pose great threats on the currently used public key cryptographic algorithms such as RSA and ECC. As a promising candidate secure against attackers equipped with quantum computational power, multivariate public key cryptosystems (MPKCs) have attracted increasing attention in recently years. Unfortunately, the existing MPKCs can only be used as a multivariate signature scheme, and it remains unknown how to construct an efficient MPKC enabling secure encryption. Furthermore, some multivariate signature schemes have been shown insecure in recent years, and it is also not trivial to build MPKC which can serve as a secure signature scheme. By employing the basic MQ-trapdoors, this paper proposes a novel MPKC and shows how it can be used as a multivariate signature scheme and a multivariate encryption scheme, respectively. The goal is achieved by incorporating our new hash authentication techniques and some modification methods such as the Shamir's minus method. Thorough analysis shows that our schemes are secure and efficient. Our MPKC gives a positive response to the challenges in multivariate public key cryptography.

关键词： cryptography post-quantum cryptography MQ problem hash function

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