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Spatio-temporal pattern analysis of single-trial EEG signals recorded during visual object recognition

Science china(Information Sciences) 2011年第12期54卷 2519-2527页

作者： WANG ChangMing 1 , HU XiaoPing 3 , YAO Li 1,2., XIONG Shi 2.& ZHANG JiaCai 2.1 National key laboratory of {2. Neuroscience and learning, beijing normal University, beijing 100875, china 2.College of Information Science and Technology, beijing normal University, beijing 100875, china 3 Biomedical Imaging Technology Center, Emory University/Georgia Institute of Technology, Atlanta 3032., USA National key laboratory of {2. Neuroscience and learning Beijing Normal University Beijing China Biomedical Imaging Technology Center Emory University/Georgia Institute of Technology Atlanta USA College of Information Science and Technology Beijing Normal University Beijing China

Object discrimination is a fundamental cognitive function for human brains. In this study, we utilized an analysis approach for single-trial electroencephalography (EEG) to analyze the spatio-temporal activation patterns of visual objects processing in human brains, and attempted to apply it to discriminate different visual objects. The spatial patterns were respectively extracted from scalp EEG and the reconstructed cortical sources, while the experiment participants were perceiving 4 different categories of visual objects (faces, buildings, cats and cars). By classifying the patterns extracted from single-trial EEG, the presented visual objects could be discriminated by a computer, and the classification accuracies may provide a quantitative index to evaluate the spatial differences of the brain activations related to different visual objects. Our results demonstrated that the spatial patterns on both the scalp and the sources levels resulted in higher classification accuracies than chance rate. We also examined the classification results using temporally non-overlapping time intervals of different event-related potential (ERP) components. The temporal changes of classification accuracies may reflect the temporal distribution of the discriminative information in the EEG responses. The present pattern extraction and classification methods may compose a computational model for single-trial EEG data analysis in investigations of the spatio-temporal activation patterns for object recognition. These spatio-temporal patterns in EEG may be useful to identifying the discriminative spatial areas and time stages to improve the accuracies and efficiencies of object discrimination. In addition, investigating and utilizing humans'cognitive mechanisms of object recognition may improve computers' processing efficiency of visual information.

关键词： EEG spatio-temporal pattern object recognition single-trial analysis visual information processing

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Information flow and controlling in regularization inversion of quantitative remote sensing

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Science china Earth Sciences 2005年第1期48卷 74-83页

作者： YANG Hua, XU Wangli, ZHAO Hongrui, CHEN Xue & WANG Jindi Research Center for Remote Sensing and GIS, School of Geography, beijing normal University, {2. key laboratory of Remote Sensing Science, beijing key laboratory for Remote Sensing of Environment and Digital Cities, beijing 100875, china Department of Mathematics, beijing normal University, beijing 100875, china Research Center for Remote Sensing and GIS School of Geography Beijing Normal University State Key Laboratory of Remote Sensing Science Beijing Key Laboratory for Remote Sensing of Environment and Digital Cities Beijing China Department of Mathematics Beijing Normal University Beijing China

In order to minimize uncertainty of the inversed parameters to the largest extent by making full use of the limited information in remote sensing data, it is necessary to understand what the information flow in quantitative remote sensing model inversion is, thus control the information flow. Aiming at this, the paper takes the linear kernel-driven model inversion as an example. At first, the information flow in different inversion methods is calculated and analyzed, then the effect of information flow controlled by multi-stage inversion strategy is studied, finally, an information matrix based on USM is defined to control information flow in inversion. It shows that using Shannon entropy decrease of the inversed parameters can express information flow more properly. Changing the weight of a priori knowledge in inversion or fixing parameters and partitioning datasets in multi-stage inversion strategy can control information flow. In regularization inversion of remote sensing, information matrix based on USM may be a better tool for quantitatively controlling information flow.

关键词： regularization inversion, information flow, Shannon entropy decrease, information matrix.

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An improved exponential filter for fast nonlinear registration of brain magnetic resonance images

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Progress in Natural Science:Materials International 2009年第6期19卷 759-767页

作者： Zhiying Long a, Li Yao a,b, Kewei Chen c, Danling Peng a a state key {2. of cognitive Neuroscience and learning, beijing normal University, beijing 100875, china b School of Information Science and Technology, beijing normal University, beijing 100875, china c Banner Alzheimer Institute (BAI) & Samaritan PET Center, Phoenix, AZ, USA state key {2. of cognitive Neuroscience and learning Beijing Normal University Beijing 100875 China School of Information Science and Technology Beijing Normal University Beijing 100875 China Banner Alzheimer Institute (BAI) & Samaritan PET Center Phoenix AZ USA

A linear elastic convolution filter was derived from the eigenfunctions of the Navier-Stokes differential operator by Bro-Nielsen in order to match images with large deformations. Due to the complexity of constructing the elastic convolution filter, the algorithm’s efficiency reduces rapidly with the increase in the image’s size. In our previous work, a simple two-sided exponential filter with high efficiency was proposed to approximate an elastic filter. However, its poor smoothness may degenerate the performance. In this paper, a new exponential filter was constructed by utilizing a modified nonlinear curve fitting method to approximate the elastic filter. The new filter’s good smoothness makes its performance comparable to an elastic filter. Its simple and separable form makes the algorithm’s speed faster than the elastic filter. Furthermore, our experiments demonstrated that the new filter was suitable for both the elastic and fluid models.

关键词： Exponential filter Nonlinear Registration Magnetic resonance imaging

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Multiple time scale evaluation of the energy balance during the maize growing season,and a new reason for energy imbalance

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Science china Earth Sciences 2009年第1期52卷 108-117页

作者： GUO JianXia1,2.BIAN LinGen3 & DAI YongJiu2.1 Meteorological Observation Center of china Meteorological Administration,beijing 100081,{2. 2.state key laboratory of Remote Sensing Science,School of Geography and Remote Sensing Science,beijing normal University,beijing 100875,{2. 3 Chinese Academy of Meteorological Sciences,beijing 100081,{2. Meteorological Observation Center of china Meteorological Administration Beijing China state key {2. of Remote Sensing Science School of Geography and Remote Sensing Science Beijing Normal University Beijing China Chinese Academy of Meteorological Sciences Beijing China

Energy imbalance is a common problem associated with the measurement of surface energy using the eddy covariance *** the evaluation of the energy balance,people usually pay more attention to the statistical result that the effective energy(the sum of sensible and latent heat) is systematically lower than the available energy(the difference of net radiation and ground heat flux).However,little attention has been paid to the existence of the reversed situation when the effective energy is larger than the available energy or their contribution to the overall energy closure *** this paper,based on the analysis of the energy balance on multiple time scales across the maize growth season,we conclude that the non-synchronization of energy components is the main reason for the existence of the reversed *** shifting the phase of the effective energy components half an hour ahead,the rates of energy closure over all time scales are improved and dramatically reduce the number of the half-hourly samples when the energy ratio exceeds 1 or is below *** to the characteristics of the energy distribution and transformation over multiple time scales,latent heat is always the main type of energy cost,and the residual of the energy balance increases with the growth of the maize plant surpassing the sensible heat for seventy *** is suggested that the heat storage and photosynthetic energy play an important role in the energy balance during the growing period of maize.

关键词： maize energy balance multiple time scale energy hysteresis

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A HIGH-ORDER-ACCURATE DIFFERENCE SCHEME WITH UNCONDITIONAL STABILITY FOR THE DIFFUSION EQUATION ON NONUNIFORM GRIDS

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Journal of Hydrodynamics 2001年第1期13卷 92-98页

作者： Wang Xuan, Yang Zhi-feng state key {2. of Environment Simulation and Pollution Control, Institute of Environmental Sciences, beijing normal University, beijing 100875, china[WT5”HZ] beijing normal Univ. Beijing 100875 China

WT5”BZ]A high-order-accurate difference scheme with unconditional stability is developed for the diffusion equation on nonuniform grids. The theoretical analysis shows that the accuracy of this scheme is between third order and fourth order, and fourth-order accuracy is achieved in the case of the same grid steps being used within the computational domain. Two numerical examples are given to demonst ate the advantages of the proposed scheme. Compared with the conventional difference scheme, more accurate numerical solution can be obtained by using the proposed scheme even with relatively larger grid sizes. It is also pointed out that the appropriate structure of the nonuniform grid can not only make the proposed scheme more practical, but lead to a solution superior to that for a uniform grid structure. [WT5”HZ]

关键词： ]finite difference scheme diffusion equation nonuniform grid high accuracy computational fluid dynamics

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Dense coding scheme using superpositions of Bell-states and its NMR implementation

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Science china(Physics,Mechanics & Astronomy) 2005年第1期48卷 57-67页

作者： ZHANG Jingfu, XIE Jingyi, DENG Zhiwei & LU Zhiheng key laboratory for Quantum Information and Measurements, Department of Physics, Tsinghua University, {2. 100084, china Center for Quantum Information, Tsinghua University, {2. 100084, china Department of Materials Science and Engineering, {2. normal University, beijing 100875, china Testing and Analytical Center, {2. normal University, beijing 100875, china Department of Physics, {2. normal University, beijing 100875, china key laboratory for Quantum Information and Measurements Department of Physics Tsinghua University Beijing 100084 China Center for Quantum Information Tsinghua University Beijing 100084 China Department of Materials Science and Engineering Beijing 100875 China Testing and Analytical Center Beijing Normal University Beijing 100875 China Department of Physics Beijing Normal University Beijing 100875 China

Dense coding using superpositions of Bell-states is proposed. The generalized Grover's algorithm is used to prepare the initial entangled states, and the reverse process of the quantum algorithm is used to determine the entangled state in the decoding measurement. Compared with the previous schemes, the superpositions of two Bell-states are exploited. Our scheme is demonstrated using a nuclear magnetic resonance (NMR)quantum computer. The corresponding manipulations are obtained. Experimental results show a good agreement between theory and experiment. We also generalize the scheme to transmit eight messages by introducing an additional two-state system.

关键词： dense coding, superpositions of Bell-states, generalized Grover's algorithm, nuclear magnetic res-onance, quantum computer.

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Early ERP effects on the scaling of spatial attention in visual search

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Progress in Natural Science:Materials International 2008年第4期18卷 381-386页

作者： Ya-Nan Niu a,b, Jing-Han Wei a, Yue-Jia Luo a,c, a Institute of Psychology, Chinese Academy of Sciences, beijing 100101, china b Graduate School of Chinese Academy of Sciences, beijing 100049, china c state key laboratory of cognitive Neuroscience and learning, beijing normal University, 19 Xin-wai Avenue, beijing 100875, china Institute of Psychology Chinese Academy of Sciences Beijing 100101 China Graduate School of Chinese Academy of Sciences Beijing 100049 China state key {2. of cognitive Neuroscience and learning Beijing Normal University 19 Xin-wai Avenue Beijing 100875 China

This article describes the examination of the spatial ’scaling’ effect of visual attention with the technique of event-related potential (ERP). Eighteen participants were involved in a visual search task in which the cue-target paradigm was used. The search array was three concentric circles consisting of randomly selected English letters that were equally distributed in each circle. The behavioral and ERP data were recorded, respectively. The behavioral results showed that the response time increased and the response accuracy decreased with the increase of precue size. The ERPs amplitude of P1 and N1 components evoked by search array increased with the reduction of precue size. However, the latencies of these ERP components did not show significant differences between conditions. The hierarchical data of both behavioral assessment and ERPs provided evidence for the spatial ’scaling’ effect of visual attention. The amplitudes of P1 and N1 components may be used as indices to examine the effect of spatial ’scaling’. In different tasks, the display-set size of stimuli and the task complexity may be important factors that affect the attention allocation.

关键词： Visual search Spatial attention ‘Scaling’ effect Event-related potential

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Effects of nitrogen ion implantation on Ca^(2.) concentration and membrane potential of pollen cell

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Chinese Science Bulletin 2001年第20期46卷 1691-1693页

作者： HUANG Zhonglian, JING Yanping, ZHU Guoli, LU Ting, ZHOU Hongyu & REN Haiyun1. key laboratory of Cell Proliferation and Regulation Biology of the Ministry of Education, {2. normal University, beijing 100875, china 2. key laboratory of Plant Physiology and Biochemistry of the Ministry of Agriculture, china Agriculture University, {2. 100094, china 3. Institution of Low Energy Nuclear Physics, {2. normal University, beijing 100875, china key laboratory of Cell Proliferation Regulation Biology of Min. of Educ. Beijing Normal University Beijing 100875 China

The effects of low energy nitrogen ion implantation on Ca2. concentration and membrane potential of illy (Mum davidii Duch) pollen cell have been studied. The results showed that the Ca2. concentration was increased when pollen grain was implanted by nitrogen ion with energy 100 keV and dose 1013 ions/cm2. However, the increase of Ca2. concentration was partly inhibited by the addition of Ca2. channel inhibitor depending on dose. And nitrogen ion implantation caused depolarization of pollen cell membrane potential. In other words, membrane potential was increased, but the effect decreased by adding Ca2. channel inhibitor. However, it was still significantly higher than the membrane potential of control cells. It was indicated that the depolarization of cell membrane potential opened the calcium channel on the membrane that caused the increasing of intracel-lular calcium concentration. This might be an earlier step of the effect of low energy nitrogen ion implantation on pollen germination.

关键词： nitrogen ion implantation lily pollen calcium concentration membrane potential.

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Parameter determination to calculate water environmental capacity in Zhangweinan Canal Sub-basin in china

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Journal of Environmental Sciences 2010年第6期22卷 904-907页

作者： Yingxia Li ,Ruzhi Qiu,Zhifeng Yang,Chunhui Li,Jingshan Yu state key {2. of Water Environment Simulation,School of Environment,beijing normal University,beijing,100875,china. state key {2. of Water Environment Simulation School of Environment Beijing Normal University Beijing 100875 China

Zhangweinan canal sub-basin （ZWN） has the most serious water resource shortage and water pollution problems in north of china. To calculate the water environmental capacity in ZWN, determination methods for design flow rates and degradation coefficients were discussed in this study. Results showed that 90% and 50% hydrological guarantee flow rates were suitable to be the design flow rates for rainy and dry seasons, respectively. Degradation coefficients of CODMn and NH3-N were 0.2. day^-1 and 0.15 day^-1 for branch streams and 0.5 day^-1 and 0.2. day^-1 for mainstreams, respectively in ZWN. With one-dimensional water quality simulation model, water environmental capacities were calculated to be 82.139 tons/yr for CODMn and 2.94 tons/yr for NH3-N in ZWN.

关键词： degradation coefficient design flow rate water environmental capacity Zhangweinan

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A MACRO-SCALE SEMI-DISTRIBUTED HYDROLOGICAL MODEL AND APPLICATION TO THE DATONG RIVER VALLEY

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Journal of Hydrodynamics 2005年第6期17卷 667-676页

作者： YANG Zhi-feng LIU Lu-liu SHEN Zhen-yao GORDON G. Huang state key {2. of Water Environmental Simulation School of Environment Beijing Normal Uni- versity Beijing 100875 China National Climate Center Beijing 100081 China Faculty of Engineering University of Regina Canada

A daily distributed hydrological model was developed using routine hydro meteorological data on the basis of the raster DEM and land cover data. Then the model was used to model daily runoff of the Datong River Valley located in the upper catchment of the Yellow River Basin. The runoff comprises surface flow, subsurface flow and ground water flow. Evapotranspiration comprises canopy evaporation, snow sublimation and soil evapotranspiration. The infiltration to the soil was estimated with improved Green-Ampt model, and the potential evapotranspiration is estimated with Morton CRAE method, which only needs the routine meteorological data. Simulation results and the comparison with semi distributed SLURP hydrological model show that the structure of the model presented herein is reasonable.

关键词： hydrological model Yellow River GIS runoff

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