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Fuzzy dynamic characteristic model based attitude control of hypersonic vehicle in gliding phase

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science china(Information sciences) 2011年第3期54卷 448-459页

作者： LUO Xiong 1,2 & li Jiang 1 1 Department of computer science and technology, Key Laboratory of Advanced Control of Iron and Steel Process (Ministry of Education), university of science and technology Beijing, Beijing 100083, china 2 National Laboratory of Space Intelligent Control, Beijing 100190, china Department of computer science and technology Key Laboratory of Advanced Control of Iron and Steel Process (Ministry of Education) University of Science and Technology Beijing Beijing China National Laboratory of Space Intelligent Control Beijing China

The intelligent autonomous control of hypersonic vehicles has aroused great interest from the field of spacecraft. To solve the problem of longitudinal attitude control of hypersonic vehicle in gliding phase, a new intelligent controller is proposed in this paper. This new controller is based on the fuzzy dynamic characteristic modeling method. The fuzzy logic is introduced into the characteristic modeling by dividing the whole restriction range into several subspaces. Simulations show that this modification greatly improves the performance of the original method. With the same whole restriction range the fuzzy dynamic characteristic modeling decreases the time of convergence, and at the same time makes the attitude angle tracing more precise and robust. Since the sub-model is a characteristic model that has stronger adaptiveness than a fixed local model, the number of fuzzy rules is greatly reduced. Our model sharply reduces the complexity in constructing a fuzzy dynamic model. Finally, simulation results are given to show the effectiveness of the proposed approach in dealing with the attitude control problem of hypersonic vehicle in gliding phase.

关键词： hypersonic vehicle gliding attitude control fuzzy dynamic characteristic modeling

Solving A Kind of High Complexity Multi-Objective Problems by A Fast Algorithm

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wuhan university Journal of Natural sciences 2003年第S1期8卷 183-188页

作者： Zeng San-you, Ding li-xin, Kang li-shanDepartment of computer science,china university of Geosciences, wuhan 43.074, Hubei, china Department of computer science, Zhuzhou Institute of technology , Zhuzhou 412008, Hunan, china State Key Laboratory of Software Engineering, wuhan university, wuhan 430072, Hubei, china Department of computer science China University of GeoSciences Wuhan Hubei China Department of computer science Zhuzhou Institute of Technology Zhuzhou Hunan China State Key Laboratory of Software Engineering Wuhan University Wuhan Hubei China

A fast algorithm is proposed to solve a kind of high complexity multi-objective problems in this paper. It takes advantages of both the orthogonal design method to search evenly, and the statistical optimal method to speed up the computation. It is very suitable for solving high complexity problems, and quickly yields solutions which converge to the Pareto-optimal set with high precision and uniform distribution. Some complicated multi-objective problems are solved by the algorithm and the results show that the algorithm is not only fast but also superior to other MOGAS and MOEAs, such as the currently efficient algorithm SPEA, in terms of the precision, quantity and distribution of solutions.

关键词： evolutionary algorithms orthogonal design multi-objective optimization Pareto-optimal set

pH-Dependent Stability of EGX, A Multi-functional Cellulase from Mollusca, Ampullaria crossean

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Acta Biochimica et Biophysica Sinica 2004年第9期36卷 603-608页

作者： Wen-Ying li2, Ji WANG1, Yan-Hong li1, ming DING1, Gen-Jun XU1,3, Lan-Ying liU2, and Fu-Kun ZHAO1,3* 1Key Laboratory of Proteomics, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological sciences, the Chinese Academy of sciences,Graduate school of the Chinese Academy of sciences, Shanghai 200031, china 2College of life science, Jilin university, Changchun 130023, china College of life science, Zhejiang university of science and technology, Hangzhou 310018, china College of life science Jilin UniversityChangchun 130023 China Key Laboratory of Proteomics Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences the Chinese Academy of Sciences Graduate School of the Chinese Academy of SciencesShanghai 200031 China College of life science Zhejiang University of Science and TechnologyHangzhou 310018 China

The cellulase activity and stability of EGX, a multi-functional cellulase previously purified from the mollusca Ampullaria crossean, was systematically studied under different pH. The pH induced con- formation and stability change of EGX have been investigated by using the intrinsic fluorescence, ANS fluorescence and CD spectrum. It has been found that the conformation and activity of this cellulase were strongly dependent on the pH. EGX was stable for both the enzyme activity and the conformation from pH 5.6 to pH 7.4. As shown by intrinsic and ANS fluorescence, no red shift of emission maximum occurred and a negligible intensity change was observed at pH 5.6–7.4. The activity of EGX remained about 80% in pH 5.6–7.4 and obviously decreased out of side the pH range. Urea-induced changes in EGX at pH 5.4 and pH 8.0 were measured by intrinsic fluorescence and CD spectrum. At pH 5.4, a significantly red shift of emission maximum occurred when the concentration of urea was 5 M compared to the concentration was 3 M at pH 8.0. The α-helix at pH 5.4 was 40.51% in the absence of urea and 31.04% in the presence of 4 M urea. At pH 8.0 the α-helix was 7.23% in the presence of 4 M urea. The data indicated that EGX was much susceptible to urea-induced unfolding at pH 8.0 and much stable at pH 5.4. The greater pH dependent stability of EGX may allow the enzyme to adequately catalyze the hydrolysis of cellulosic materials under natural or industrial extreme conditions.

关键词： multi-functional cellulase stability Ampullaria crossean fluorescence spectroscopy pH-dependent structural change CD spectrum

The optimization of replica distribution in the unstructured overlays

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science china(Information sciences) 2012年第3期55卷 714-722页

作者： FENG GuoFu1,2 , li WenZhong2, LU SangLu2, CHEN DaoXu2 & BUYYA Rajkumar3 1school of Information science, Nanjing Audit university, Nanjing 210029, china 2State Key Laboratory of Novel Software technology, Nanjing university, Nanjing 210093, china 3Department of computer science and Software Engineering, The university of Melbourne, Victoria 3010, Australia school of Information science Nanjing Audit University Nanjing China State Key Laboratory of Novel Software technology Nanjing University Nanjing China Department of computer science and Software Engineering The University of Melbourne Victoria Australia

Replication is a widely used technique in unstructured overlays to improve content availability or system performance. A fundamental question often addressed by previous work focused on: how many replicas ought to be allocated for each data item given the fixed query rates and limited storage capability? In this paper, we have put forth two optimal replica distributions to achieve the highest success rate and the lowest message consumption. Especially, we have investigated the influence of item size on replica distribution. Our results show that Square-Root Replication, which is traditionally considered to be optimal, is not always the best choice. Our study offers a new deep understanding of resource managment in self-organized unstructured overlays.

关键词： unstructured overlay item size distribution query rate success rate expected search size

Mobile Robot Hierarchical Simultaneous Localization and Mapping Using Monocular Vision

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Journal of Shanghai Jiaotong university(science) 2007年第6期12卷 765-772页

作者：厉茂海洪炳熔罗荣华 school of computer science and technology Harbin Inst. of Technology school of computer science and Eng. South China Univ. of Technology

A hierarchical mobile robot simultaneous localization and mapping (SLAM) method that allows us to obtain accurate maps was presented. The local map level is composed of a set of local metric feature maps that are guaranteed to be statistically independent. The global level is a topological graph whose arcs are labeled with the relative location between local maps. An estimation of these relative locations is maintained with local map alignment algorithm, and more accurate estimation is calculated through a global minimization procedure using the loop closure constraint. The local map is built with Rao-Blackwellised particle filter (RBPF), where the particle filter is used to extending the path posterior by sampling new poses. The landmark position estimation and update is implemented through extended Kalman filter (EKF). Monocular vision mounted on the robot tracks the 3D natural point landmarks, which are structured with matching scale invariant feature transform (SIFT) feature pairs. The matching for multi-dimension SIFT features is implemented with a KD-tree in the time cost of O(lbN). Experiment results on Pioneer mobile robot in a real indoor environment show the superior performance of our proposed method.

关键词： mobile robot hierarchical simultaneous localization and mapping (SLAM) Rao-Blackwellised particle filter (RBPF) monocular vision scale invariant feature transform

Parallel Computing of Ocean General Circulation Model

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wuhan university Journal of Natural sciences 2001年第Z1期6卷 568-573页

作者： Zhang li lun 1, Song Jun qiang 1, li Xiao mei 2 1. school of computer science, National university of Defense technology, Changsha 410073, china 2. Department of computer, Institute of Command technology, Beijing 100081, china school of computer science National University of Defense Technology Changsha China Department of computer Institute of Command Technology Beijing China

This paper discusses the parallel computing of the third generation Ocean General Circulation Model (OGCM) from the State Key Laboratory of Numerical Modeling for Atmospheric science and Geophysical Fluid Dynamics(LASG),Institute of Atmosphere Physics(IAP). Meanwhile, several optimization strategies for parallel computing of OGCM (POGCM) on Scalable Shared Memory Multiprocessor (S2MP) are presented. Using Message Passing Interface (MPI), we obtain super linear speedup on SGI Origin 2000 for parallel OGCM(POGCM) after optimization.

关键词： parallel computing OGCM optimization strategy S2MP

Performance-based methodology for assessing seismic vulnerability and capacity of buildings

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Earthquake Engineering and Engineering Vibration 2010年第2期9卷 157-165页

作者： lin Shibin1, Xie lili1, 2,Gong Maosheng1,2 and li ming1,3 1.Institute of Engineering Mechanics,china Earthquake Administration, Harbin 150080, china 2.school of Civil Engineering,Harbin Institute of technology,Harbin 150090, china 3.school of Civil Engineering,Shenyang Jianzhu university,Shenyang 11016, china Institute of Engineering Mechanics China Earthquake Administration Harbin China school of Civil Engineering Harbin Institute of Technology Harbin China school of Civil Engineering Shenyang Jianzhu University Shenyang China

This paper presents a performance-based methodology for the assessment of seismic vulnerability and capacity of buildings. The vulnerability assessment methodology is based on the HAZUS methodology and the improved capacity- demand-diagram method. The spectral displacement (Sd) of performance points on a capacity curve is used to estimate the damage level of a building. The relationship between Sd and peak ground acceleration (PGA) is established, and then a new vulnerability function is expressed in terms of PGA. Furthermore, the expected value of the seismic capacity index (SCev) is provided to estimate the seismic capacity of buildings based on the probability distribution of damage levels and the corresponding seismic capacity index. The results indicate that the proposed vulnerability methodology is able to assess seismic damage of a large number of building stock directly and quickly following an earthquake. The SCev provides an effective index to measure the seismic capacity of buildings and illustrate the relationship between the seismic capacity of buildings and seismic action. The estimated result is compared with damage surveys of the cities of Dujiangyan and Jiangyou in the M8.0 Wenchuan earthquake, revealing that the methodology is acceptable for seismic risk assessment and decision making. The primary reasons for discrepancies between the estimated results and the damage surveys are discussed.

关键词： performance-based vulnerability building damage seismic capacity software HAZUS

Survey of DHT topology construction techniques in virtual computing environments

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science china(Information sciences) 2011年第11期54卷 2221-2235页

作者： ZHANG Yiming 1,2,LU XiCheng 1,2 & li DongSheng 1,21 National Laboratory for Parallel and Distributed Processing (PDL),Changsha 410073,china 2 school of computer,National university of Defense technology,Changsha 410073,china National Laboratory for Parallel and Distributed Processing (PDL) Changsha China school of computer National University of Defense Technology Changsha China

The Internet-based virtual computing environment (iVCE) is a novel network computing *** characteristics of growth,autonomy,and diversity of Internet resources present great challenges to resource sharing in *** DHT overlay (DHT for short) technique has various advantages such as high scalability,low latency,and desirable availability,and is thus an important approach to realizing efficient resource *** construction is a key technique for structured overlays that realizes basic overlay functions including dynamic maintenance and message *** this paper,we first introduce the traditional techniques of DHT topology construction,focusing mainly on dynamic maintenance and message routing of typical DHTs,DHT indexing techniques for complex queries,and DHT grouping techniques for matching domain *** then present recent advances in DHT topology construction techniques in iVCE taking advantage of the characteristics of Internet ***,we discuss the future of DHT topology construction techniques.

关键词： virtual computing environments DHT overlays topology construction distributed indexing flexible routing

Cross-Layer Design of Energy-Saving AODV Routing Protocol

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Transactions of Tianjin university 2009年第5期15卷 343-349页

作者：李冰金志刚舒炎泰 school of computer science and technology Tianjin University school of Electronics and Information Engineering Tianjin University

Since most ad hoc mobile devices today operate on batteries,the power consumption becomes an important *** paper proposes a cross-layer design of energy-aware ad hoc on-demand distance vector(CEAODV) routing protocol which adopts cross-layer mechanism and energy-aware metric to improve AODV routing protocol to reduce the energy consumption and then prolong the life of the whole *** CEAODV,the link layer and the routing layer work together to choose the optimized transmission power for nodes and the route for *** link layer provides the energy consumption information for the routing layer and the routing layer chooses route accordingly and conversely controls the link layer to adjust the transmission *** simulation result shows that CEAODV can outperform AODV to save more *** can reduce the consumed energy by about 8%over traditional energy-aware *** the performance is better when the traffic load is higher in the network.

关键词： ad hoc network energy conservation cross-layer routing