Journal of University of Chinese Academy of Sciences

Simulation of oscillation of simple pendulum by symplectic algorithm

LIU Cheng-Bao, CHEN Yu-Fu

2012, (6): 721-730. DOI: 10.7523/j.issn.2095-6134.2012.6.001

Simple pendulum is a classical model in both physics and mathematics and its large-angle oscillation is a difficult problem in research. We use symplectic algorithm to solve this problem from the viewpoint of Hamiltonian system instead of Newtonian system. The second- and fourth-order symplectic schemes are constructed, and the solutions are stable and accurate in long time simulation. Furthermore, based on good properties of symplectic scheme, we give an approximate-extreme point method to estimate oscillation period.

Oscillation of second-order dynamic equations with nonlinear neutral term on time scales

YANG Jia-Shan

2012, (6): 731-737. DOI: 10.7523/j.issn.2095-6134.2012.6.002

Abstract ( 1107 ) PDF (KB) ( 4 )

Oscillation of second-order nonlinear variable delay dynamic equations with nonlinear neutral term on time scales is discussed. By using the time scale theory and some necessary analytic techniques and by introducing parameter functions and the generalized Riccati transformation, some sufficient conditions for the oscillation of the equations are obtained. Some examples are given to illustrate our main conclusions.

Oscillation of a class of even-order neutral partial functional differential equations with continuous deviating arguments and diffusion coefficients

LIN Wen-Xian

2012, (6): 738-742. DOI: 10.7523/j.issn.2095-6134.2012.6.003

Abstract ( 979 ) PDF (KB) ( 3 )

Oscillation of a class of even-order neutral partial functional differential equations with continuous deviating arguments and nonlinear diffusion coefficients is studied. By employing the generalized Riccati transformation and the differential inequalities, some new sufficient conditions for oscillation of all the solutions of such equations are obtained under Robin and Dirichlet boundary value conditions. The results show that the oscillation is caused by delay. The results generalize some recently published results.

Some applications of the matrix expression of Boolean function via semi-tensor product

ZHAO Yin, GAO Xu, CHENG Dai-Zhan

2012, (6): 743-749. DOI: 10.7523/j.issn.2095-6134.2012.6.004

Abstract ( 1538 ) PDF (KB) ( 3 )

Boolean function can be expressed in matrix form using semi-tensor product of matrices. Using this approach, we give a neat proof of the conversion of a Boolean function from the truth table to the polynomial form. The linear structure of Boolean functions is also investigated.

Variational level set methods for multiphase image segmentation based on piecewise constant

LI Zhong-Wei, NI Ming-Jiu

2012, (6): 750-756. DOI: 10.7523/j.issn.2095-6134.2012.6.005

Abstract ( 1165 ) PDF (KB) ( 2 )

A multiphase image segmentation model with the noise removal ability is proposed based on the variational level set mehod. The new model can complete the segmentation and the denoising process simultaneously. Therefore it can reduce the execution time of image segmentation. On the other hand, we construct the characteristic function of the regional division based on the decimal-binary number conversion. Finally, the proposed model is applied to the segmentation of the synthetic images and medical images. The experimental results show that the proposed model can extract the targets from the noise image faster than Chan-Vese model.

Construction method of three-dimensional information for image decryption based on the scalar diffraction theory

FU Chang-Ming, YANG Yu-Hua, LI Tuo, CHEN Yue-Dong, CHENG Dong, WANG Ya-Li, SHI Yi-Shi

2012, (6): 757-766. DOI: 10.7523/j.issn.2095-6134.2012.6.006

Abstract ( 1132 ) PDF (KB) ( 4 )

Construction method of three-dimensional (3D) information with judicious choices of phase retardation is proposed to improve the decryption quality. The simple 3D information can be constructed with multiple two-dimensional distribution functions perpendicular to the axis, in both the cases of off-line and in-line. Optical 3D information encryption is performed based on phase extraction algorithm. Computer simulations show that the decryption quality declines in the in-line constructions compared with that in the off-line ones. Schemes for the phase retardation setting are provided with the analysis of respective constraint conditions.

Construction and EST analysis of suppression subtractive hybridization library of Alternanthera philoxeroides inflorescence

WANG Lan-Ying, CHEN Jie, LIU Wei

2012, (6): 767-774. DOI: 10.7523/j.issn.2095-6134.2012.6.007

Abstract ( 1135 ) PDF (KB) ( 3 )

Functions of the SSH cDNA library of two different inflorescences of hermaphrodite and pistillate of Alternanthera philoxeroides were sorted into eight different categories, involving the development of sex differentiation of flowers, the process of metabolism, cytoplasmic gene etc. Sex differentiation ESTs point to eight kinds of gene families, including homeobox ZIP, MADS-box, CCLS4 protein family, mitochondria male-fertile, and cytoplasmic male-sterility genes.

Extraction of water information based on LBV transformation of TM image using the object-oriented method

ZHOU Wen-Xin, HE Long-Hua, MA Rong-Hua, LIU Gui-Lin, YUAN Hui-Li

2012, (6): 775-779. DOI: 10.7523/j.issn.2095-6134.2012.6.008

Abstract ( 1426 ) PDF (KB) ( 3 )

Taking the Nanjing city as the research area, we transform the TM image with the LBV way to extract the water information based on object-oriented classification method. The experiment results show that the extraction accuracy of water information reaches 94.6%. This method not only removes the influence of the mountain shadow and city buildings, but also reduces the salt-phenomenon. This method is simple and has practical value. It is suitable for automatic extraction of water information.

Dynamic evaluation of ecological integrity based on landscape pattern index

LI Xin, TIAN Wei

2012, (6): 780-785. DOI: 10.7523/j.issn.2095-6134.2012.6.009

Abstract ( 1203 ) PDF (KB) ( 5 )

On the basis of the theory and method of landscape ecology, ecological integrity evaluation for the surroundings of Fengman hydropower station was carried out by using the landscape pattern index in terms of three aspects: landscape dominance, vegetation biomass, and landscape diversity. The results show that the comprehensive index value of the ecological integrity decreases to 0.8419(2008) from 0.8698(1979); the ecological integrity of this area has not been substantially changed; and the degradation trend is obvious.

Accuracy of knife-edge method in MTF assessment

LIU Liang, LI Xian-Bin, JIANG Xiao-Guang, WU Wei, ZHANG Bao-Jun, YANG Dian-Hua

2012, (6): 786-792. DOI: 10.7523/j.issn.2095-6134.2012.6.010

Abstract ( 1440 ) PDF (KB) ( 3 )

Modulation transfer function (MTF) is a key parameter for assessment of the imaging performance of in-flight optical sensors. This study focuses on the influences of major factors on the accuracy of knife-edge method by using theoretical analysis and simulation experiments. The analyzed factors include atmosphere, the incline angle of target, the contrast and random noise of target, the edge detection accuracy, and the ERF curve-fitting model. Accuracies in MTF assessment under different simulation parameters are also analyzed. The analysis results are instructive for implementation of on-orbit MTF assessment using knife-edge method.

Analysis and measurement of SAR antenna's phase center

SUN Hui-Feng, DENG Yun-Kai, LEI Hong, SHI Li

2012, (6): 793-798. DOI: 10.7523/j.issn.2095-6134.2012.6.011

Abstract ( 1868 ) PDF (KB) ( 3 )

On the basis of the principle of SAR(synthetic aperture radar) system, significance of SAR antenna's phase center is analyzed and two parameters are summed up: LMS location of aperture-plane phase center and relative inserted phase shift. By using the GO(geometrical optics) principle and least square estimation, the measurement method for the two parameters is presented and verified by a two-aperture phased array antenna.

An interoperability evaluation tool of PKI applications 

CAI Quan-Wei, LIN Jing-Qiang, JING Ji-Wu, SHANG Ming

2012, (6): 799-804. DOI: 10.7523/j.issn.2095-6134.2012.6.012

Abstract ( 1250 ) PDF (KB) ( 4 )

Interoperability problem has become one of the main obstacles to PKI deployment and usage. China has drafted the national standard PKI Interoperability Evaluation Criteria to evaluate the interoperability levels of PKI systems and PKI applications. However, there are still difficulties in design and implementation of an evaluation tool by following the national standard, especially in PKI applications. We analyze the problems in the design and implementation of PKI interoperability evaluation tool and propose the solutions to these problems.

Nonsingular circulant matrices over finite fields

ZHAO Yan, LIN Dong-Dai

2012, (6): 805-814. DOI: 10.7523/j.issn.2095-6134.2012.6.013

Abstract ( 1348 ) PDF (KB) ( 3 )

Study on the number of nonsingular circulant matrices over finite fields is significant in both maticx theory and practice. We characterize the properties of circulant matrices over finite fields and find two different ways to solve the problem. Finally, we give the formula to figure out the number of the nonsingular circulant matrices over finite fields in all circumstances and analyze some applications of circulant matrices in MPKC.

Automatic generation of attack vectors for stored-XSS

CHEN Jing-Feng, WANG Yi-Ding, ZHANG Yu-Qing, LIU Qi-Xu

2012, (6): 815-820. DOI: 10.7523/j.issn.2095-6134.2012.6.014

Abstract ( 1476 ) PDF (KB) ( 2 )

The stored-XSS (cross-site scripting) is generally more serious than the other modalities of XSS. We study the characteristics and trigger mechanism of stored-XSS, propose an generation method of attack vectors for stored-XSS, and accomplish a tool which can generate the attack vectors automatically. After we used this tool in testing the blog systems of two popular video-sharing sites in China, we found 6 types of attcak vectors which can trigger stored-XSS. The results of the testing experiments show the effectiveness of our method and also show the potential security risk in the video-sharing sites.

Iterative pose estimation of a 3D rigid object based on general 2D-3D contour point correspondence

LENG Da-Wei, MA Hong-Bing, SUN Wei-Dong

2012, (6): 821-828. DOI: 10.7523/j.issn.2095-6134.2012.6.015

Abstract ( 1425 ) PDF (KB) ( 4 )

Pose estimation of 3D rigid object based on monocular vision is studied. Considering the insufficiency of state-of-art iterative methods in convergence radius and convergence speed, we propose a new iterative pose estimation method based on general 2D-3D contour point correspondence. The proposed method focuses on explicitly establishing the 2D-3D feature projection correspondence between the input image and object's 3D model with the general 2D contour points of the input image, and then estimates object's 3D pose parameters. Experiment results show that the proposed method provides notable improvements in algorithm complexity, convergence radius, and convergence speed.

Equilibrium degree evaluation of scientific research output based on Boston matrix

CHEN Yuan-Ping, ZHOU Zi-Bo, SHAO Pei-Pei

2012, (6): 829-833. DOI: 10.7523/j.issn.2095-6134.2012.6.016

Abstract ( 1019 ) PDF (KB) ( 4 )

We use Boston matrix to evaluate the equilibrium degree of scientific research output. Considering the actualities of scientific management, we redefine the coordinates and quadrants of the matrix. With Gini coefficients of scientific research output which are calculated based on CAS ARP system data, we give a relatively objective equilibrium degree evaluation of scientific research output.

Brief Report Geometry of minimal surfaces in complex projective spaces

FU Jing-Chao, YU Yan

2012, (6): 834-840. DOI: 10.7523/j.issn.2095-6134.2012.6.017

Abstract ( 1007 ) PDF (KB) ( 2 )

We compute normal scaler curvature and obtain some basic relationships between Gaussian curvature, Kähler angle, length square of the second fundamental form, and normal scaler curvature. We also give some conditions for a conformal minimal sphere to have constant Kähler angle.

Structure-activity relationship study on inhibition of fatty acid synthase by xanthones

QUAN Xiao-Fang, MA Xiao-Feng

2012, (6): 841-846. DOI: 10.7523/j.issn.2095-6134.2012.6.018

Abstract ( 938 ) PDF (KB) ( 3 )

Fatty acid synthase (FAS), an important enzyme catalyzing the synthesis of long-chain fatty acid in vivo, has been reported to be a potential target for treatment of obesity. We found that xanthones with different functional groups and substituents have different inhibition activities on FAS, and the IC₅₀ values range from 1.24 μmol/L to 1000 μmol/L and above. Structure-activity relationships for these compounds were then analyzed, and some structure-activity rules were established.

Prokaryotic expression, purification, and identification of GST-β-catenin-His double labeled fusion protein

YIN Hui-Long, YUAN Li

2012, (6): 847-852. DOI: 10.7523/j.issn.2095-6134.2012.6.019

Abstract ( 1292 ) PDF (KB) ( 2 )

The cDNA sequence of β-catenin was amplified through RT-PCR with 6xHis tag added in the gene downstream, cloned into the vector pGEX-4T-1. The plasmid transformed into BL21pLysS was induced by IPTG. The induced fusion protein was purified stepwise using Glutathione Sepharose 4B and Ni columns. The final protein ran on SDS-PAGE with a specific band at the expected size of 114 kDa. Western Blotting showed that the purified protein can be recognized by the anti-β-catenin, anti-GST, and anti-His antibodies, respectively. All these results provide a basis for further study of β-catenin function.

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