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A three-dimensional variational ocean data assimilation system:Scheme and preliminary results

Science china Earth Sciences 2006年第11期49卷 1212-1222页

作者： ZHU Jiang1,2, ZHOU Guangqing1, YAN Changxiang1, FU Weiwei1 & YOU Xiaobao1,3 1. International Center for Climate and Environment Sciences, institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, china 2. Jiangsu Key Laboratory of Meteorological Disaster, Nanjing university of information Science and technology, Nanjing 210044, china 3. Beijing institute of Applied Meteorology, Beijing 100029, china 1. International Center for Climate and Environment Sciences Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China 2. Jiangsu Key Laboratory of Meteorological Disaster Nanjing University of Information Science and Technology Nanjing 210044 China 3. Beijing institute of Applied Meteorology Beijing 100029 China

A new 3DVAR-based Ocean Variational Analysis System (OVALS) is developed. OVALS is capable of assimilating in situ sea water temperature and salinity observations and satellite altimetry data. As a component of OVALS, a new variational scheme is proposed to assimilate the sea surface height data. This scheme considers both the vertical correlation of background errors and the nonlinear temperature-salinity relationship which is derived from the generalization of the linear balance constraints to the nonlinear in the 3DVAR. By this scheme, the model temperature and salinity fields are directly adjusted from the altimetry data. Additionally, OVALS can assimilate the temperature and salinity profiles from the ARGO floats which have been implemented in recent years and some temperature and salinity data such as from expendable bathythermograph, moored ocean buoys, etc. A 21-year assimilation experiment is carried out by using OVALS and the Tropical Pacific circulation model. The results show that the assimilation system may effectively improve the estimations of temperature and salinity by assimilating all kinds of observations. Moreover, the root mean square errors of temperature and salinity in the upper depth less than 420 m reach 0.63℃ and 0.34 psu.

关键词： data assimilation, 3DVAR, sea surface height, ARGO floats.

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Artificial Neural Networks:Current Applications in Modern Medicine

Artificial Neural Networks:Current Applications in Modern Me...

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2010 International Conference on Computer and Communication Technologies in Agriculture Engineering (CCTAE 2010)

作者： SHI Lei 1 2 1. information Science and technology College dalian Maritime university dalian 116026 china WANG Xing-cheng 1 2. College of information Science and Engineering Bohai university Jinzhou 121000 china.

Artificial neural networks （ANNs） are a form of artificial computer intelligence which are the mathematical algorithms, generated by computers. They are the digitized model of biological brain and can detect complex nonlinear relationships between dependent as well as independent variables in a data where human brain may fail to detect. Nowadays, ANNs are widely used for medical applications in various disciplines of medicine such as diagnosis, electronic signal analysis, medical image analysis and radiology. In this paper, authors have summarized various applications of ANNs in modern medicine.

关键词： Artificial neural networks application medicine

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Repetitive learning control of nonlinear systems over finite intervals

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Science china(information Sciences) 2010年第1期53卷 115-128页

作者： SUN MingXuan1, WANG DanWei2 & CHEN PengNian3 1College of information Engineering, Zhejiang university of technology, Hangzhou 310014, china 2School of Electrical and Electronic Engineering, Nanyang Technological university, Singapore 639794 3Department of Mathematics, china institute of Metrology, Hangzhou 310018, china 1. College of information Engineering Zhejiang University of Technology Hangzhou 310014 China2. School of Electrical and Electronic Engineering Nanyang Technological University Singapore 639794 Singapore3. Department of Mathematics China Institute of Metrology Hangzhou 310018 China

Iterative learning control requires initial repositioning, while the time functions to be learned should be of periodicity in repetitive control. However, there are cases in practice where the time-varying unknowns are not periodic but repetitive, and repetitive learning control is applicable with avoidance of initial repositioning. In this paper, repetitive learning control designs are presented for a broader class of nonlinear systems over finite intervals. The Freeman formula is modified and used for stabilization of the nominal nonlinear time-varying system undertaken. The global stability of the learning system and asymptotic convergence of the tracking error are established through analysis of both partially and fully saturated learning algorithms, respectively. The repetitive learning control method is theoretically shown to be effective in dealing with time-varying parametric uncertainties.

关键词： Initial condition problem convergence iterative learning control repetitive control repetitive learning control nonlinear systems

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Advanced information feedback strategy in intelligent two-route traffic flow systems

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Science china(information Sciences) 2010年第11期53卷 2265-2271页

作者： DONG ChuanFei1,2, MA Xu1,3 & WANG BingHong1,4 1Department of Modern Physics and nonlinear Science Center, university of Science and technology of china (USTC), Hefei 230026, china 2School of Earth and Atmospheric Sciences, Georgia institute of technology, Atlanta, GA 30332, USA 3 Department of Physics, Syracuse university, Syracuse, NY 13244, USA 4The Research Center for Complex System Science, university of Shanghai for Science and technology and Shanghai Academy of System Science, Shanghai 200093, china 1. Department of Modern Physics and nonlinear Science Center University of Science and Technology of China (USTC) Hefei 230026 China2. School of Earth and Atmospheric Sciences Georgia Institute of Technology Atlanta GA 30332 USA3. Department of Physics Syracuse University Syracuse NY 13244 USA4. The Research Center for Complex System Science University of Shanghai for Science and Technology and Shanghai Academy of System Science Shanghai 200093 China

The optimal information feedback has a significant effect on many socioeconomic systems like stock market and traffic systems aiming to make full use of resources. In this paper, we study dynamics of traffic flow with real-time information. The influence of a feedback strategy named vehicle number feedback strategy (VNFS) is introduced, in which we only calculate the vehicle number of first 500 route sites from the entrance. Moreover, the two-route traffic system has only one entrance and one exit, which is different from those in the previous work. Our model incorporates the effects of adaptability into the cellular automaton models of traffic flow, and simulation results by adopting this optimal information feedback strategy have demonstrated higher efficiency in controlling spatial distribution of traffic patterns than the other three information feedback strategies, i.e., TTFS, MVFS and CCFS.

关键词： vehicle number feedback strategy two-route selecting traffic flow intelligent vehicle cellular automaton model

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Investigation of fine and complex vortex circulation structures

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Science china Earth Sciences 2010年第10期53卷 1552-1558页

作者： LUO ZheXian1,MA GeLan1 & PING Fan2 1 Remote Sensing College,Nanjing university of information Science and technology,Nanjing 210044,china 2 Laboratory of Cloud-Precipitation Physics and Severe Storms(LACS),institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,china 1. Remote Sensing College Nanjing University of Information Science and Technology Nanjing 210044 China2. Laboratory of Cloud-Precipitation Physics and Severe Storms (LACS) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The formation and evolution of fine and complicated vortex circulation structures were investigated using a two-dimensional quasi-geostrophic barotropic model *** find that the highly localized asymmetric and complex configuration of energy transfer flux between large-and small-scale components is caused by the nonlinear interaction between a large-scale vortex with an initial axi-symmetric flow and four beta meso-scale *** complex structure is characterized by a fine pattern,which contains seven closed systems with spatial scales of less than 100 km,embedded in a positive flux wave train and a negative wave train,*** average wind speed decreased with time in the positive flux region,but was nearly unchanged in the negative flux *** pattern reveals the evolutionary asymmetry and localization of wind speed of the major *** track of the major vortex center has a trend toward the center of the negative flux center,indicating that there is a certain relation between the complex structure of the energy transfer flux and the motion of the major vortex *** results imply that the formation and evolution of the fine and complex structure should be attributed to the nonlinear interaction between the vortices at different spatial scales.

关键词： vortex complex structure non-linear interaction energy cascade

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Moment tensor analysis of the acoustic emission source in the rock damage process

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Progress in Natural Science:Materials International 2005年第7期15卷 609-613页

作者： YU Huaizhong, ZHU Qingyong, YIN Xiangchu and WANG Yucang ( State Key Laboratory of Earthquake Dynamics, institute of Geology, china Earthquake Administration, Beijing 100029, china State Key Laboratory of nonlinear Mechanics, institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, china School of Mathematics and Computational Science, Zhongshan university, Guangzhou 510275, china Center for Analysis and Prediction, china Seismological Bureau, Beijing 100036, china Quakes, Department of Earth Science, university of Queensland, Brishbane, Austrialia) State Key Laboratory of Earthquake Dynamics Institute of Geology China Earthquake Administration Beijing 100029 China. State Key Laboratory of nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China. School of Mathematics and Computational Science Zhongshan University Guangzhou 510275 China. Center for Analysis and Prediction China Seismological Bureau Beijing 100036 China. Quakes Department of Earth Science University of Queensland Brishbane Austrialia

To further investigate the mechanism of acoustic emission (AE) in the rock fracture experiment, moment tensor analysis was carried out. The AE sources characterized by crack sizes, orientations and fracture modes, are represented by a time-dependent moment tensor. Since the waveforms recorded by AE monitors correlate to the moment tensors, we prefer to select the P wave amplitude from the full-space Green's function of homogeneous and isotropic materials to determine the six independent components of the moment tensor. The moment tensor analysis was used to investigate the AE sources recorded in the experiment, and three types of micro-cracks were found, which are tensile mode, shear mode and mixture of the tensile and shear mode. In addition, the motion of micro-cracks was decided by eigenvectors of moment tensor. Results indicate that the moment tensor analysis may be used as a measurement to reflect the damage evolution of rock specimen.

关键词： moment tensor acoustic emission rock fracture.

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Characterization of plastic flow in two Zr-based bulk metallic glasses

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Science china(Technological Sciences) 2006年第4期49卷 414-424页

作者： XING Dongmei1,2, ZHANG Taihua1, LI Weihuo3 & WEI Bingchen3 1. State Key Laboratory of nonlinear Mechanics (LNM), institute of Mechanics, Chinese Academy of Sci- ences, Beijing 100080, china 2. College of Physics and Electronic information Science, Tianjin Normal university, Tianjin 300074, china 3. National Microgravity Laboratory, institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, china 1. State Key Laboratory of nonlinear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China 2. College of Physics and Electronic information Science Tianjin Normal University Tianjin 300074 China 3. National Microgravity Laboratory Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

Plastic deformation behaviors of Zr65Al10Ni10Cu15 and Zr52.5Al10Ni10Cu15Be12.5 bulk metallic glasses (BMGs) are studied by using the depth-sensing nanoindentation, microindentation and uniaxial compression. The Be-containing BMG exhibits a signifi- cantly improved overall plastic strain compared with the Be-free alloy during compressive tests. Both BMGs show a loading-rate-dependent serrated flow during nanoindentation measurements, but the Be-containing alloy exhibits a much lower critical loading rate for the disappearance of the serration than the Be-free BMG. The shear band patterns de- veloped during plastic deformation are investigated by microindentation technique, wherein much higher shear band density is found in the Be-containing alloy than in the Be-free alloy, indicating an easier nucleation of shear bands in the former BMG. The dif- ference in the plastic deformation behavior of the two BMGs can be explained by a free volume model.

关键词： Bulk metallic glass, plastic deformation, shear band, nanoindentation.

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Response synchronization: New progress in brain-visual information processing

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Chinese Science Bulletin 1999年第16期44卷 1447-1458页

作者： ZHAO Songnian, XIONG Xiaoyun, YAO Guozheng and GUO Aike1. State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry , institute of Atmospheric Physics , Chinese Academy of Sciences , Beijing 100029, china 2. Commission of the National Natural Science Foundation of china , Beijing 100083, china 3. The Center of information Science , Peking university, Beijing 100871, china 4. Open Laboratory of Visual information Processing , institute of Biophysics , Chinese Academy of Sciences , Beijing 100101, china State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Commission of the National Natural Science Foundation of china Beijing China The Center of information Science Peking University Beijing China Open Laboratory of Visual information Processing Institute of Biophysics Chinese Academy of Sciences Beijing China

Studies on brain-vision have entered a new stage, after the stimulus-induced y synchronized oscillation of neuron group activities have been discovered in cat primary visual cortex. Naturally, how to understand the visual system became a very important methodological problem. From aspects such as information processing, nonlinear dynamics and neuronal network, some primary problems in vision studies have been deeply discussed, which are

关键词： neuron group (neural population) synchro-oscillation computational theory of vision response synchroniza-tion.

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On Robust Stability of a Class of Uncertain nonlinear Systems with Time-Varying Delay

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Systems Science and Systems Engineering 2002年第2期11卷 129-135页

作者： NIAN Xiao-hongDepartment of Mechanics and Engineering Sciences, Peking university,Beijing 100871 , china institute of information and Control Engineering,Central South university, Changsha 410075, china Department of Mechanics and Engineering Sciences Peking UniversityBeijing 100871 China institute of information and Control Engineering Central South University Changsha 410075 China

The problem of robust stability of a class of uncertain nonlinear dynamical systems with time-delay is considered. Based on the assumption that the nominal system is stable, some sufficient conditions on robust stability of uncertain nonlinear dynamical systems with time-delay are derived. Some analytical methods and a type of Lyapunov functional are used to investigate such sufficient conditions. The results obtained in this paper are applicable to perturbed time-delay systems with unbounded time-varying delay. Some previous results are improved and a numerical example is given to demonstrate the validity of our results.

关键词： robust stability nonlinear time-delay uncertainty

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模糊控制器的实时精确算法与优化设计

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计算机工程与应用 2004年第20期40卷 116-118,122页

作者：修智宏任光海军大连舰艇学院指控信息系大连116018 大连海事大学轮机工程学院大连116026

将T-S型模糊控制器与PID控制器相结合,提出了TS-PID模糊控制器模型。推导出了输入采用正规模糊集、三角形全交迭隶属度函数的典型TS-PID模糊控制器的插值解析表达式,揭示了TS-PID模糊控制器本质上是一种非线性PID控制器,为实际应用提供... 详细信息

将T-S型模糊控制器与PID控制器相结合,提出了TS-PID模糊控制器模型。推导出了输入采用正规模糊集、三角形全交迭隶属度函数的典型TS-PID模糊控制器的插值解析表达式,揭示了TS-PID模糊控制器本质上是一种非线性PID控制器,为实际应用提供了一种快速精确的控制算法。基于该插值表达式,进一步探讨了利用遗传算法对TS-PID模糊控制器进行优化设计的方法。

关键词：模糊控制 PID控制器实时算法插值函数

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