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Adaptive neural control based on HGO for hypersonic flight vehicles

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science China(Information sciences) 2011年第3期54卷 511-520页

作者： XU Bin 1,2 , GAO DaoXiang 3.& WANG ShiXing 1 1 department of computer science and Technology, Tsinghua {3., Beijing 100084, China 2 Autonomous System Lab, ETH Zurich Zurich 8092, Switzerland 3.School of Technology, Beijing Forestry {3., Beijing 100083. China 1. department of computer science and Technology Tsinghua University Beijing 100084 China2. Autonomous System Lab ETH Zurich Zurich 8092 Switzerland3. School of Technology Beijing Forestry University Beijing 100083 China

This paper describes the design of adaptive neural controller for the longitudinal dynamics of a generic hypersonic flight vehicle (HFV) which are decomposed into two functional systems, namely the altitude subsystem and the velocity subsystem. For each subsystem, one adaptive neural controller is investigated based on the normal output-feedback formulation. For the altitude subsystem, the high gain observer (HGO) is taken to estimate the unknown newly defined states. Only one neural network (NN) is employed to approximate the lumped uncertain system nonlinearity during the controller design which is considerably simpler than the ones based on back-stepping scheme with the strict-feedback form. The Lyapunov stability of the NN weights and filtered tracking error are guaranteed in the semiglobal sense. Numerical simulation study of step response demonstrates the effectiveness of the proposed strategy in spite of system uncertainty.

关键词： adaptive neural control hypersonic flight vehicle high gain observer output-feedback

Experimental measurement of growth patterns on fossil corals:Secular variation in ancient Earth-Sun distances

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Chinese science Bulletin 2010年第35期55卷 4010-4017页

作者： ZHANG WeiJia1,3.4,LI ZhengBin2,3.& LEI Yang1 1 department of Physics,Peking university,Beijing 100871,China 2 department of Electrical Engineering and {3. science,Peking university,Beijing 100871,China 3.State Key Laboratory of Advanced Optical Communication Systems & Networks,Peking university,Beijing 100871,China 4 Committee of Yuanpei Honors Program,Peking university,Beijing 100871,China department of Physics Peking University Beijing 100871 China State Key Laboratory of Advanced Optical Communication Systems & Networks Peking University Beijing 100871 China Committee of Yuanpei Honors Program Peking University Beijing 100871 China department of Electrical Engineering and computer science Peking University Beijing 100871 China

In recent years,much attention has been given to the increase in the Earth-Sun distance,with the modern rate reported as 5-15 m/cy on the basis of astronomical ***,traditional methods cannot measure the ancient leaving rates,so a myriad of research attempting to provide explanations were met with unmatched *** this paper we consider that the growth patterns on fossils could reflect the ancient Earth-Sun *** mechanical analysis of both the Earth-Sun and Earth-Moon systems,these patterns confirmed an increase in the Earth-Sun *** a large number of well-preserved specimens and new technology available,both the modern and ancient leaving rates could be measured with high precision,and it was found that the Earth has been leaving the Sun over the past 0.53.billion *** Earth's semi-major axis was 146 million kilometers at the beginning of the Phanerozoic Eon,equating to 97.6% of its current *** modern leaving rates are 5-14 m/cy,whereas the ancient rates were much *** results indicate a special expansion with an average expansion coefficient of 0.57H0 and deceleration in the form of Hubble *** the basis of experimental results,the Earth's semi-major axis could be represented by a simple formula that matches fossil measurements.

关键词：地球太阳古代距离生长模式实验石珊瑚量化

Bayesian cognitive trust model based self-clustering algorithm for MANETs

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science China(Information sciences) 2010年第3期53卷 494-505页

作者： WANG Wei1,2,3.& ZENG GuoSun1,2,3.department of computer science & Technology, Tongji {3., Shanghai 200092, China 2Tongji Branch, National Engineering & Technology Center of High Performance computer, Shanghai 200092, China 3.ey Loboratory of Embedded System and Service Computing, Ministry of Education, Shanghai 200092, China 1. department of computer science & Technology Tongji University Shanghai 200092 China2. Tongji Branch National Engineering & Technology Center of High Performance Computer Shanghai 200092 China3. Key Loboratory of Embedded System and Service Computing Ministry of Education Shanghai 200092 China

With the introduction of mobile Ad hoc networks (MANETs), nodes are able to participate in a dynamic network which lacks an underlying infrastructure. Before two nodes agree to interact, they must trust that each will satisfy the security and privacy requirements of the other. In this paper, using the cognition inspired method from the brain informatics (BI), we present a novel approach to improving the search efficiency and scalability of MANETs by clustering nodes based on cognitive trust mechanism. The trust relationship is formed by evaluating the level of trust using Bayesian statistic analysis, and clusters can be formed and maintained autonomously by nodes with only partial knowledge. Simulation experiments show that each node can form and join proper clusters, which improve the interaction performance of the entire network. The essence of the underlying reason is analyzed through the theory of complex networks, revealing great scalability of this method.

关键词： trust model MANET self-clustering Bayesian method cognitive mobile

INTERIOR ERROR ESTIMATES FOR NONCONFORMINGFINITE ELEMENT METHODS OF THE STOKES EQUATIONS

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Journal of Computational Mathematics 1999年第5期17卷 475-494页

作者： Xiao-bo Liu(department of Mathematics and computer science Clarkson {3. Box 5815, Potsdam,NY 13.99-5815, USA) Clarkson Univ Dept Math & Comp Sci Potsdam NY 13699 USA

Interior error estimates are derived for nonconforming stable mixed finite element discretizations of the stationary Stokes equations. As an application, interiorconvergences of difference quotients of the finite element solution are obtained forthe derivatives of the exact solution when the mesh satisfies some translation invariant condition. For the linear element, it is proved that the average of thegradients of the finite element solution at the midpoint of two interior adjacenttriangles approximates the gradient of the exact solution quadratically.

关键词： Interior error estimates Nonconforming element Stokes equations.

Singularly Perturbed Solution for Nonlinear Equations of Fourth Order with Two Parameters

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Journal of Shanghai Jiaotong university(science) 2008年第4期13卷 495-498页

作者：陈丽华莫嘉琪刘树德 department of Mathematics and computer science Fuqing Branch of Fujian Normal University department of Mathematics Anhui Normal Univeristy

A class of singularly perturbed boundary value problem for nonlinear equation of fourth order with two parameters is considered. Under suitable conditions, the existence and asymptotic behavior of solution for boundar... 详细信息

关键词： nonlinear two parameters singular perturbation

A New Admissibility Condition of Discrete-time Singular Systems with Time-varying Delays

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International Journal of Automation and computing 2012年第5期9卷 480-486页

作者： Yong-Yun Shao 1,3.Xiao-Dong Liu 1,2 Xin Sun 3.Zhan Su 4 1 Transportation Management College, Dalian Maritime university, Dalian 116026, China 2 department of Mathematics, Dalian Maritime university, Dalian 116026, China 3.department of computer and Mathematics Teaching, Shenyang Normal university, Shenyang 11003., China 4 Institute of Systems science, Northeastern university, Shenyang 110004, China 1. Transportation Management College Dalian Maritime University Dalian 116026 China 3. department of computer and Mathematics Teaching Shenyang Normal University Shenyang 110034 China 2. department of Mathematics Dalian Maritime University Dalian 116026 China 4. Institute of Systems science Northeastern University Shenyang 110004 China

This paper gives a novel delay-dependent admissibility condition of discrete-time singular systems with time-varying delays. For convenience, the time-varying delay is assumed to be the sum of delay lower bound and the integral multiples of a constant delay. Specially, if the constant delay is of unit length, the delay is an interval-like time-varying delay. The proposed admissibility condition is presented and expressed in terms of linear matrix inequality (LMI) by Lyapunov approach. Generally, the uncertainty of time-varying delay would lead to conservatism. In this paper, this critical issue is tackled by accurately estimating the time-varying delay. Consequently, the proposed admissibility condition is less conservative than the existing results, which is demonstrated by a numerical example.

关键词： Singular systems discrete-time delay-dependent admissibility time-varying delay

Cluster based node scheduling method for wireless sensor networks

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science China(Information sciences) 2012年第4期55卷 755-764页

作者： WANG Lei 1,2,WEI RuiZhong 2 & TIAN ZiHong 2,3.1 College of Software,Hunan university,Changsha 410082,China 2 department of computer {3.,Lakehead university,Thunder Bay P7B 5E1,Canada 3.Mathematics and Information {3. College,Hebei Normal university,Shijiazhuang 050016,China 1. College of Software Hunan University Changsha 410082 China2. Department of Computer Science Lakehead University Thunder Bay P7B 5E1 Canada3. Mathematics and Information Science College Hebei Normal University Shijiazhuang 050016 China

By researching on the node scheduling problem of m-covered and connected sensor networks,a new concept of two-hops-cluster is proposed in this paper,and based on it,a new distributed node scheduling algorithm THCNS for allocating all nodes in the sensor network into k(k≤m) different groups {0,1,...,k 1} is designed,without requiring location *** algorithm guarantees that each group to be connected and maintains the coverage ratio with high *** analysis and simulation results show that it has better performance than previous randomized scheduling scheme,and can prolong the lifetime of the sensor network effectively.

关键词： node scheduling lifetime wireless sensor network two-hops-cluster

AutoProc: An automatic proactive replication scheme for P2P storage

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science China(Information sciences) 2011年第6期54卷 1151-1160页

作者： YANG Zhi & DAI YaFei computer science department, Peking {3., Beijing 100871, China 1. computer science department Peking University Beijing 100871 China

Due to the prevalence of peer departures, P2P storage systems need to constantly generate replicas for high durability. However, few existing systems are able to select the right replication rate that balances replication cost and durability, e.g., minimizing replication cost without threatening the durability target. In this paper, we propose a method called AutoProc to automate the replication process in P2P storage systems. AutoProc employs two key techniques to enable cost-effective replication: correctly adapting replication rate with a reliability model, and replicating objects at the right order with a reliability indicator. Extensive simulations based on the real system failure trace show that AutoProc achieves the near-optimal performance.

关键词： P2P storage churn durability fault tolerance proactive replication resource usage

The Study on Scaling Function of L2（Rs）

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Chinese Quarterly Journal of Mathematics 2007年第4期 567-573页

作者： HUANG Yong-dong~1 LI Hua~2 WU Guo-chang~3.(1.department of Mathematics,North university for nationalities,Yinchuan 750021,China 2.department of Mathematics and computer,Xinyang Vocational and Technical College,Xinyang 464000,China 3.School of sciences,Xi'an Jiaotong university,Xi'an 710049,China)

In this paper,using the orthonormal multiresolution analysis（MRA）of L2(R?), we get two important properties of the scaling function with dilation matrix A=MI of L2(R?).These properties are characterized by some ineq... 详细信息

关键词： multiresolution analysis compact support scaling function Fouries transform