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Research on applying physical chaos generator to spacecraft information security

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science china(Technological sciences) 2009年第5期52卷 1463-1470页

作者： ZHAO HePing State Key laboratory of information Security,Graduate University of Chinese Academy of sciences,Beijing 100049,{3. {3. Academy of Space technology,Beijing 100094,{3. State Key laboratory of information Security Graduate University of Chinese Academy of Sciences Beijing China china Academy of Space technology Beijing China

The effectiveness of a short-length message extension method based on physical chaos generator was analyzed and the entropy of the extended message was calculated in this *** analysis demon-strated that with the mentioned method the entropy of short-length messages,which are repeatedly used in spacecraft data systems,is obviously increased,and the security of transmission is enhanced as *** paper also presented an improvement of the protocol for secret key agreement presented by *** and *** of depending on characteristics of communication channel,this method takes advantage of the random data produced by physical chaos generator to preset the initial parameters of the procedure on both sides of communication,so that the procedure and quantity of cipher key can be precisely *** method can be used to cipher key management of se-cure communication between long life-span spacecraft and ground system.

关键词： physical chaos generator spacecraft information security message extension cipher key management

Vision navigation algorithm for mine agent based on quaternion

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中国有色金属学会会刊：英文版 2011年第S3期21卷 610-615页

作者： LI Ke-zhao1, 4, LEI Wei-wei1, 2, GUO Zeng-zhang1, 2, WU Li-xin3. ZHANG Qin4 1. School of Survey and Land information Engineering, Henan Polytechnic University, Jiaozuo 454003. china 2. Key laboratory of Mine Spatial information Technologies of State Bureau of Surveying and Mapping, Henan Polytechnic University, Jiaozuo 454003. china 3. College of Resources and Civil Engineering, Northeastern University, Shenyang 110819, china 4. College of Geology Engineering and Geomatics, Chang’an University, Xi’an 710054, china School of Survey and Land information Engineering Henan Polytechnic University Jiaozuo 454003 China College of Geology Engineering and Geomatics Chang'an University Xi'an 710054 China Key laboratory of Mine Spatial information Technologies of State Bureau of Surveying and Mapping Henan Polytechnic University Jiaozuo 454003 China College of Resources and Civil Engineering Northeastern University Shenyang 110819 China

Autonomous relative navigation is the key technology in mining or rescuing. On the basis of mine requirement and the theories of machine vision, an autonomous relative navigation algorithm for mine agent based on quaternion was proposed. In rotation transformation, this algorithm was represented by using quaternion. Because the Jacobi matrix of this method is lower than that of Hall algorithm, the calculation efficiency is improved by using this algorithm. The results of these experiments show that the computation burden of this algorithm based on quaternion is about half that of Hall algorithm. This algorithm based on quaternion is improved as a valid way to solve the problem of mine real-time navigation.

关键词： quaternion mine agent vision navigation

Geophysical methods for the study of sedimentary cycles

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Petroleum science 2009年第3期6卷 259-265页

作者： Xu Jingling Liu Luofu Wang Guiwen Shen Jinsong Zhang Chunhua School of Resources and information technology China University of Petroleum Beijing 102249 China State Key laboratory of Petroleum Resource and Prospecting China University of Petroleum Beijing 102249 China Department of Computer science and technology China University of Petroleum Beijing 102249 China

We present the wavelet depth-frequency analysis and variable-scale frequency cycle analysis methods to study sedimentary cycles. The spectrum analysis, variable-scale frequency cycle analysis, and wavelet depth-frequency analysis methods are mainly discussed to distinguish sedimentary cycles of different levels. The spectrum analysis method established the relationship between the spectrum characteristics and the thickness and number of sedimentary cycles. Both the variable-scale frequency cycle analysis and the wavelet depth-frequency analysis are based on the wavelet transform. The variable-scale frequency cycle analysis is used to obtain the relationship between the periodic changes of frequency in different scales and sedimentary cycles, and the wavelet depth-frequency analysis is used to obtain the relationship between migration changes of frequency energy clusters and sedimentary cycles. We designed a soft-ware system to process actual logging data from the Changqing Oilfield to analyze the sedimentary cycles, which verified the effectiveness of the three methods, and good results were obtained.

关键词： Sedimentary cycles spectrum analysis wavelet depth-frequency analysis variable-scale frequency cycle analysis

The characteristic properties of PEDOT nano-particle based on reversed micelle method

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science china(Technological sciences) 2010年第9期53卷 2355-2362页

作者： ZHENG HuaJing,JIANG YaDong,XU JianHua & YANG YaJie State Key laboratory of Electronic Thin Films & Integrated Devices,School of Optoelectronic information,University of Electronic science and {3. of china,Chengdu 610054,china State Key laboratory of Electronic Thin Films & Integrated Devices School of Optoelectronic Information University of Electronic Science and Technology of China Chengdu China

Based on the study of a new type of conducting polymer poly (3.4-ethylenedioxythiophene) (PEDOT),this paper focuses on the preparation and the materials properties of PEDOT nanoparticles made by reversed micelle *** on optical,electrical and the thermal stability of PEDOT nanoparticles were carried *** main results were as follows: The small-sized PEDOT nanoparticles were prepared by different methods,such as ultraviolet/visible (UV-Vis) spectroscopy,fourier-transform infrared (FT-IR) spectrum,scanning electron microscopy (SEM) and so *** Bragg peaks of nanoparticles at 6.7°,12.7°,25° were observed by XRD and the good orientation of molecular chain was attributed to the effective doping of toluene-p-sulfonic acid,which also resulted in an enhancement of thermal stability of nanoparticles compared with the conventional ***,the gas sensitivity of nanoparticles deposited on quartz crystal microbalance (QCM) was studied and the nanopartices deposited device exhibited excellent sensitivity to HCl gas at low *** sensitivity of the nanoparticles by the reverse micelle was better than that of the common PEDOT particles.

关键词： poly (3 4-ethylenedioxythiophene) conducting polymer reversed micelle n-particle photoelectric properties thermal stability

Numerical study of the auroral particle transport in the polar upper atmosphere

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science china(Technological sciences) 2008年第10期51卷 1759-1771页

作者： CAI HongTao1,2, MA ShuYing1,2 & PU ZuYin3.1 School of Electronic information, Wuhan University, Wuhan 43.079, china 2 Key laboratory of Geospace Environment and Geodesy, Ministry of Education of PRC, Wuhan 43.079, china 3.School of Earth and Space sciences, Peking University, Beijing 100871, china School of Electronic information Wuhan University Wuhan China Key laboratory of Geospace Environment and Geodesy Ministry of Education of PRC Wuhan China School of Earth and Space sciences Peking University Beijing China

Starting from the Boltzmann equation and with some reasonable assumptions, a one-dimensional transport equation of charged energetic particles is derived by taking account of major interactions with neutral species in the upper atmosphere, including the processes of elastic scattering, the excitation, the ionization and the secondary electron production. The transport equation is numerically solved, for a simplified atmosphere consisting only of nitrogen molecules (N2), to obtain the variations of incident electron fluxes as a function of altitude, energy and pitch angle. The model results can describe fairly the transport characteristics of pre-cipitating auroral electron spectra in the polar upper atmosphere; meanwhile the N2 ionization rates calculated from the modeled differential flux spectra also exhibit good agreements with existing empirical models in terms of several key parameters. Taking the energy flux spectra of precipitating electrons observed by FAST satellite flying over EISCAT site on May 15, 1997 as model inputs, the model-calculated ionization rate profile of neutral atmosphere consists reasonably with that recon-structed from electron density measurements by the radar.

关键词： aurora particle precipitation polar upper atmosphere electron transport equation numerical simulation

A software cascading faults model

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science china(information sciences) 2011年第11期54卷 2454-2458页

作者： LIU YanHeng 1,2,LIU XueLian 3.& WANG Jian 1,2 1 Key laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education,Jilin University,Changchun 13.012,china 2 College of Computer science and {3.,Jilin University,Changchun 13.012,china 3.College of Software,Jilin University,Changchun 13.012,china Key laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education Jilin University Changchun China College of Computer science and technology Jilin University Changchun China College of Software Jilin University Changchun China

Functions and call relations are extracted into nodes and edges,respectively,by which a novel topological model is *** directional edges and the corresponding weight values express the call relations and tightness *** introducing two concepts of function fault-tolerant capability and software fault intensity and by designing a allocation rule on fault-tolerant capability,a cascading fault model is built to explore fault propagation *** on practical software networks show that a weak fault intensity,a small number of initial faults,and a strong fault-tolerant capability can slow down the spreading *** functions with more call relations and more closer tightness contribute more to the stability of the whole system.

关键词： software fault tolerant cascading faults fault-tolerant capability fault intensity

A fast successive over-relaxation algorithm for force-directed network graph drawing

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science china(information sciences) 2012年第3期55卷 677-688页

作者： WANG YongXian & WANG ZhengHua national Key laboratory for Parallel and Distributed Processing, national University of Defense {3., Changsha 410073. china national Key laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha China

Force-directed approach is one of the most widely used methods in graph drawing research. There are two main problems with the traditional force-directed algorithms. First, there is no mature theory to ensure the convergence of iteration sequence used in the algorithm and further, it is hard to estimate the rate of convergence even if the convergence is satisfied. Second, the running time cost is increased intolerablely in drawing largescale graphs, and therefore the advantages of the force-directed approach are limited in practice. This paper is focused on these problems and presents a sufficient condition for ensuring the convergence of iterations. We then develop a practical heuristic algorithm for speeding up the iteration in force-directed approach using a successive over-relaxation (SOR) strategy. The results of computational tests on the several benchmark graph datasets used widely in graph drawing research show that our algorithm can dramatically improve the performance of force-directed approach by decreasing both the number of iterations and running time, and is 1.5 times faster than the latter on average.

关键词： graph drawing graph layout successive over-relaxation force-directed algorithm

Modeling and Control of Welding Flexible Manufacturing Cell Using Petri Net

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Journal of Materials science & technology 2001年第1期17卷 185-186页

作者： Tao QIU Shanben CHEN Yuntao WANG and Lin WU national Key laboratory of Advanced Welding Production technology, Harbin institute of technology, Harbin 150001, china Harbin Inst. of Technol. Harbin 150001 China

A new welding flexible manufacturing cell (WFMC) with intelligent welding sensors was investigated. Based on the analysis of information flow in WFMC, automation Petri net control model has been studied, Which can be... 详细信息

关键词： Petri Net flexible manufacturing system information flow control model Petri net

Generalized gradient projection neural networks for nonsmooth optimization problems

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science china(information sciences) 2010年第5期53卷 990-1005页

作者： LI GuoCheng 1 , SONG ShiJi 2 ? & WU Cheng 2 1 Department of Mathematics, Beijing information science and technology University, Beijing 100192, {3. 2 Department of Automation, tsinghua University, Beijing 100084, {3. Department of Mathematics Beijing Information Science and Technology University Beijing China Department of Automation Tsinghua University Beijing China

Generalized gradient projection neural network models are proposed to solve nonsmooth convex and nonconvex nonlinear programming problems over a closed convex subset of R n . By using Clarke’s generalized gradient, the neural network modeled by a differential inclusion is developed, and its dynamical behavior and optimization capabilities both for convex and nonconvex problems are rigorously analyzed in the framework of nonsmooth analysis and the differential inclusion theory. First for nonconvex optimization problems, the quasi convergence results similar to those achieved by previous work are proved. For convex optimization problems, the global convergence results are proved, i.e. any trajectory of the neural network converges to an asymptotically stable equilibrium point, which is an optimal solution of the primal problem whenever it exists. This result remains valid even if the initial condition is chosen outside the feasible set. In addition, an asymptotic control result involving a Tykhonov like regularization shows that any trajectory of the revised neural network can be forced to converge toward a particular optimal solution of the primal problem. Finally, two simulation optimization algorithms for solving the optimization and control problems are designed respectively, and three typical simulation experiments are illustrated to present the accuracy and efficiency of theoretical convergence results of this paper.

关键词： nonsmooth optimization problem generalized gradient projection networks differential inclu sions convergence