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Image universal steganalysis based on best wavelet packet decomposition

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Science china(Information Sciences) 2010年第3期53卷 634-647页

作者： LUO XiangYang1,2, LIU FenLin1, YANG ChunFang1 & WANG DaoShun2 1Information Science and technology institute, Zhengzhou 450002, china 2Department of computer Science and technology, Tsinghua University, beijing 100084, china 1. Information Science and technology institute Zhengzhou 450002 China2. Department of Computer Science and Technology Tsinghua University Beijing 100084 China

Based on the best wavelet packet decomposition of images, a new universal steganalysis method with high detection correct ratio is proposed. First, the best wavelet packet decomposition of image based on the Shannon entropy information cost function is made. Second, high order absolute characteristic function moments of histogram extracted from the coefficient subbands obtained by best wavelet packet decomposition are regarded as features. Finally, these features are processed and a back-propagation (BP) neural network is designed to classify original and stego images. Three different steganalysis algorithms for three different cases of background and application condition are presented. To validate the performance of the proposed method, a series of experiments are made for six kinds of typical steganography methods, i.e. LSB, LTSB, PMK, Jsteg, F5 and JPHide. Results show that, the average detection accuracy of the proposed method exceeds at least 6.4% and up to 15.4% and has a better universal performance than its closest competitors. Furthermore, the proposed method can provide reference for designing the pattern recognition and classification algorithm based on best wavelet packet decomposition.

关键词： steganography digital images universal steganalysis best wavelet packet decomposition BP neural network

The attractor of the stochastic generalized Ginzburg-Landau equation

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Science china Mathematics 2008年第5期51卷 955-964页

作者： GUO BoLing~1 WANG GuoLian~(2+) Li DongLong~3 1 institute of Applied Physics and Computational Mathematics,P.O.Box 8009,beijing 100088,china 2 The Graduate School of china Academy of Engineering Physics,P.O.Box 2101,beijing 100088,china 3 Department of Information and computer Science,Guangxi University of technology,Liuzhou 545006,china institute of Applied Physics Computational Mathematics P. O. Box 8009 Beijing 100088 China The Graduate School of china Academy of Engineering Physics P. O. Box 2101 Beijing 100088 China Department of Information computer Science Guangxi University of Technology Liuzhou 545006 China

The stochastic generalized Ginzburg-Landau equation with additive noise can be solved pathwise and the unique solution generates a random system. Then we prove the random system possesses a global random attractor in ... 详细信息

关键词： generalized Ginzburg-Landau equation random dynamical systems random attractor 35K05

A computer code for beam optics calculation--third order approximation

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Progress in Natural Science:Materials International 2006年第6期16卷 667-670页

作者： Lü Jianqin and LI Jinhai (institute of Heavy Ion Physics, Peking University, beijing 100871, china) [a]Institure of Heavy Ion Physics Peking University Beijing China

To calculate the beam transport in the ion optical systems accurately, a beam dynamics computer program of third order approximation is developed. Many conventional optical elements are incorporated in the program. Particle distributions of uniform type or Gaussian type in the (x, y, z) 3D ellipses can be selected by the users. The optimization procedures are provided to make the calculations reasonable and fast. The calculated results can be graphically displayed on the computer monitor.

关键词： beam transport computer program third order approximation Lie algebra.

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.

Prediction of Dynamic Wellbore Pressure in Gasified Fluid Drilling

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Petroleum Science 2007年第4期4卷 66-73页

作者： Wang Zhiming1,Ping Liqiu2 and Zou Ke2 (1. School of Petroleum Engineering,Petroleum University of china,beijing 102249,china) (2. institute of Drilling Engineering technology,CNPC,beijing 100097,china) Petr Univ china Sch Petr Engn Beijing 102249 Peoples R China CNPC Inst Drilling Engn Technol Beijing 100097 Peoples R China

The basis of designing gasified drilling is to understand the behavior of gas/liquid two-phase flow in the wellbore. The equations of mass and momentum conservation and equation of fluid flow in porous media were used to establish a dynamic model to predict wellbore pressure according to the study results of Ansari and Beggs-Brill on gas-liquid two-phase flow. The dynamic model was solved by the finite difference approach combined with the mechanistic steady state model. The mechanistic dynamic model was numerically implemented into a FORTRAN 90 computer program and could simulate the coupled flow of fluid in wellbore and reservoir. The dynamic model revealed the effects of wellhead back pressure and injection rate of gas/liquid on bottomhole pressure. The model was validated against full-scale experimental data,and its 5.0% of average relative error could satisfy the accuracy requirements in engineering design.

关键词： Gasified fluid drilling dynamic model pressure prediction model validation

Natural Language Processing in Web Data Mining

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Natural Language Processing in Web Data Mining

The Analysis and Solution of a PCP Instance

2010 IEEE 2nd Symposium on Web Society

作者： Yue Chen School of computer Science and technology,beijing institute of technology beijing,china

＜正＞This paper describes the research about Web data mining using Natural Language *** accepts arbitrary data as input from Web document and then extracts information from the document.A new method to implement Web data mining is proposed in this *** are three steps in this system. First,the Web document will be decomposed to paragraph,sentence and phrase ***,extract information from all ***,add the information to the knowledge *** methods used have proved to be efficient for Web data mining with the experimental corpus.

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The Analysis and Solution of a PCP Instance

Orthogonality in Banach spaces and orthogonal multiscale L^1-approximation

2012 National Conference on Information technology and computer Science

作者： Jing Dong School of computer Science beijing institute of technology beijing,china

In this paper,we present a heuristic rule for solving some specific PCP *** also analyze a PCP instance,and prove that this instance has no finite solution using our heuristic ***,we find this instance has a unique in... 详细信息

关键词： PCP Post Correspondence Problem Fibonacci substitution

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Chinese Science Bulletin 1999年第1期44卷 25-35页

作者： YANG LihuaDepartment of Scientific Computing and computer Applications, School of Mathematics and Computing Science, Zhongshan (Sun Yatsen) University, Guangzhou 510275, china institute of Mathematics, Chinese Academy of Sciences, beijing 100080, china Department of Scientific Computing and computer Applications School of Mathematics and Computing Science Zhongshan (Sun Yatsen) University Guangzhou China institute of Mathematics Chinese Academy of Sciences Beijing China

The orthogonality in Hilbert spaces is extended to the general Banach spaces and a concrete shift-invariant orthogonal family in L^1(R) is constructed. The corresponding projection approximation theorems and the algor... 详细信息

关键词： Banach spaces orthogonality approximation multiscale analysis.

Governing Equation and Mathematical Simulation on Ablation and Transpiration Control

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Journal of Systems Engineering and Electronics 1992年第3期3卷 44-58页

作者： Yang Xueshi and Gao Wei beijing institute of Electromechanic System Engineering, P.O. Box 3924, beijing 100854, chinaYuan Zhaoding institute of computer Application and Simulation technology, beijing 100854Xu YanhouDepartment of Modem Mechanics, University of Science and technology of china, Hefei 230026 beijing institute of Electromechanic System Engineering P.O. Box 3924 Beijing 100854 China institute of computer Application and Simulation technology Beijing 100854 Department of Modern Mechanics University of Science and Technology of China Hefei 230026

This paper represents a physical model of two -dimensional transpiration cooling control system with surface heating and ablating. The governing equation is derived and the third boundary conditions are given. They constitute a two -dimensional variable -domain distributed parameter control system in which the control parameter appears in both the governing equation and the boundary conditions. Applying time semi-step alternating direction method to difference this mathematical model, the tridiagonal difference equations are obtained. For a flying shell of electromagnetic railgun, the mathematical simulation results agree with the realistic physical process, and the control parameter not only can control the temperature of heat shield, but also can control the boundary motion effectively.

关键词： Transpiration Variable-boundary Heat transfer Mathematical simulation.