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Transport network and flow mechanism of shallow ore-bearing magma in Tongling ore cluster area

Science china Earth Sciences 2006年第4期49卷 397-407页

作者： DENG Jun1,2. WANG Qingfei1,2., HUANG Dinghua3 , WAN Li4. YANG Liqiang1,2.& GAO Bangfei1,2.1. State Key Laboratory of Geological Processes and Mineral Resources, china {2. of Geosciences, Beijing 100083, china 2. Key Laboratory of Lithosphere Tectonics and Lithoprobing Technology of Ministry of Education, china {2. of Geo- sciences, Beijing 100083, china 3. Faculty of Earth Sciences, china {2. of Geosciences, Wuhan 4.0074. china 4. school of Mathematics and information Science, guangzhou university,{12., china 1. State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083 China 2. Key Laboratory of Lithosphere Tectonics and Lithoprobing Technology of Ministry of Education China University of Geosciences Beijing 100083 China 3. Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China 4. school of Mathematics and {2. Science Guangzhou University Guangzhou 510405 China

Abundant studies revealed that shallow intrusions of the Yanshanian epoch resulted in the mass mineralization of the Tongling region. Various evidences showed there existed a concealed magma chamber at ?10 km depth in the middle part of this region during Yanshanian epoch, from which the ore-forming magma was generated and then transported to the superficial layer. Yet the transport network and flow mechanism of the shallow ore-bearing magma, the key problem associ- ated with ore-forming process, was relatively little focused on. Integrate analysis of structural me- chanics, statistical fractal and geological facts suggested that NE trending high-angle fold-related thrust faults and the tessellated basement ones served as the main pathways for the shallow magma’s transporting, moreover, the saddle void spaces among adjacent strata in the folds upon this fault system provided the place for magma’s emplacement. So the folds in the upper part and faults in the lower part of the upper crust constituted the fluid’s transport and emplacement network. During the deformation of geologic body with multi-layer structure, the layers in the upper part tended to fold when received the jacking stress from the lower part, while the lower one inclined to fault undergoing loads of the upper part. And the producing probability of this structure assemblage was highly in- creased in the condition, such as in the Tongling area, that the mechanic rigidity of the lower layers was stronger than that of the upper ones. For the pre-existence of fluid-conducting network, the top magma with high volatile in the magma chamber transported rapidly to the superficial layer in dyking pattern, located in the void spaces of folds, filled and reconstructed them. The sudden drop of pres- sure caused the fluid unmixing from the magma and mass ore-forming elements concentration. Pulse activity of the dyking may be the principal reason why magmatic bodies in the Tongling area were spatially-temporally con

关键词： Tongling, structural network, magma intrusion, fractal, dyke.

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Construction of Boolean functions with maximum algebraic immunity and count of their annihilators at lowest degree

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Science china(information Sciences) 2010年第4期53卷 780-787页

作者： DU YuSong* & PEI DingYi school of Mathematics and information Sciences,{2., guangzhou 510006,{4. 1. school of Mathematics and information Sciences Guangzhou University Guangzhou 510006 China

Boolean functions used in stream ciphers against algebraic attacks are required to have a necessary cryptographic property-high algebraic immunity (AI). In this paper, Boolean functions of even variables with the maximum AI are investigated. The number of independent annihilators at the lowest degree of Boolean functions of even variables with the maximum AI is determined. It is shown that when n is even, one can get an (n + 1)-variable Boolean function with the maximum AI from two n-variable Boolean functions with the maximum AI only if the Hamming weights of the two functions satisfy the given conditions. The nonlinearity of the Boolean functions obtained in this way is computed. Similarly, one can get an (n + 2.-variable Boolean function with the maximum AI from four n-variable Boolean functions with the maximum AI. The nonlinearity of a class of Boolean functions with the maximum AI is determined such that their Hamming weights are either the maximum or the minimum.

关键词： Boolean function algebraic attack algebraic immunity annihilator nonlinearity

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Steganalysis of stochastic modulation steganography

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Science in china(Series F) 2006年第3期49卷 273-285页

作者： HE Junhui1,2.& HUANG Jiwu1,2.1. school of information Science and Technology, Sun Yat-sen {2., guangzhou 5102.5,{4. 2. Guangdong Province Key Laboratory of information Security, guangzhou 5102.5,{4. 1. school of information Science and Technology Sun Yat-sen University Guangzhou 510275 China 2. Guangdong Province Key Laboratory of information Security Guangzhou 510275 China

Stochastic modulation steganography embeds secret message within the cover image by adding stego-noise with a specific probabilistic distribution. No method is known to be applicable to the estimation of stochastic modulation steganography. By analyzing the distributions of the horizontal pixel difference of images before and after stochastic modulation embedding, we present a new steganalytic approach to accurately estimate the length of secret message in stochastic modulation steganography. The pro- posed method first establishes a model describing the statistical relationship among the differences of the cover image, stego-image and stego-noise. In the case of stegoimage-only steganalysis, rough estimate of the distributional parameters of the cover image＇s pixel difference is obtained with the use of the provided stego-image. And grid search and Chi-square goodness of fit test are exploited to estimate the length of the secret message embedded with stochastic modulation steganography. The experimental results demonstrate that our new approach is effective for steganalyzing stochastic modulation steganography and accurately estimating the length of the secret message.

关键词： information hiding steganography steganalysis stochastic modulation statistical distribution models of difference.

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Twisted Ate pairing on hyperelliptic curves and applications

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Science china(information Sciences) 2010年第8期53卷 1528-1538页

作者： ZHANG FangGuo 1,2.1 school of information Science and Technology, Sun Yat-Sen {2., guangzhou 5102.5,{4. 2.Guangdong Key Laboratory of information Security Technology, guangzhou 5102.5,{4. 1. school of information Science and Technology Sun Yat-Sen University Guangzhou 510275 China2. Guangdong Key Laboratory of Information Security Technology Guangzhou 510275 China

In this paper we show that the twisted Ate pairing on elliptic curves can be generalized to hyperelliptic curves, and give a series of variations of the hyperelliptic Ate and twisted Ate pairings. Using the hyperelliptic Ate pairing and twisted Ate pairing, we propose a new approach to speeding up the Weil pairing computation. For some hyperelliptic curves with high degree twist, computing Weil pairing by our approach may be faster than Tate pairing, Ate pairing, and all other known pairings.

关键词： Ate pairing Weil pairing hyperelliptic curves pairing-based cryptosystems twisted curves

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A provable secure fuzzy identity based signature scheme

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Science china(information Sciences) 2012年第9期55卷 2139-2148页

作者： WANG ChangJi 1,2.1 school of information Science and Technology,Sun Yat-sen {2.,guangzhou 5102.5,{4. 2.Guangdong Province information Security Key Laboratory,Sun Yat-sen {2.,guangzhou 5102.5,{4. 1. school of information Science and Technology Sun Yat-sen University Guangzhou 510275 China2. Guangdong Province Information Security Key Laboratory Sun Yat-sen University Guangzhou 510275 China

To use biometrics identities in an identity based encryption system,Sahai and Waters first introduced the notion of fuzzy identity based encryption(FIBE) in *** et *** it to digital signature and introduced the concept of fuzzy identity based signature(FIBS) in 2.08,and constructed an FIBS scheme based on Sahai and Waters's FIBE *** this paper,we further formalize the notion and security model of FIBS scheme and propose a new construction of FIBS scheme based on bilinear *** proposed scheme not only provides shorter public parameters,private key and signature,but also have useful structures which result in more efficient verification than that of Yang et al.'s FIBS *** proposed FIBS scheme is proved to be existentially unforgeable under a chosen message attack and selective fuzzy identity attack in the random oracle model under the discrete logarithm assumption.

关键词： identity based cryptosystem fuzzy identity based encryption fuzzy identity based signature

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Efficient CRT-based residue-to-binary converter for the arbitrary moduli set

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Science china(information Sciences) 2011年第1期54卷 70-78页

作者： CHEN JianWen & YAO RuoHe school of Electronic and information Engineering,South{2. university of Technology, {4. 51064.,china 1. school of Electronic and information Engineering South China University of Technology Guangzhou 510640 China

The conversion from residue to weighted binary representation plays an important role in the residue number *** on Chinese Remainder Theorem,a new residue-to-binary converter using arbitrary moduli set is *** new converter uses the difference-correction algorithm for the conversion output and eliminates the modulo M operation,where M is the dynamic range of the residue number *** sizes of the multipliers and modular multipliers in the new converter are small,thereby reducing the area and delay of the proposed *** and synthesis results indicate that the new converter is more area-time effcient than the published converters based on Chinese Remainder Theorem.

关键词： RNS Chinese Remainder Theorem difference correction modular arithmetic residue-to-binary arbitrary moduli set

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An aperiodic phenomenon of the unscented Kalman filter in filtering noisy chaotic signals

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Progress in Natural Science:Materials International 2007年第10期17卷 1235-1240页

作者： Fan Hongjuan1, Feng Jiuchao1,2. Xie Shengli2.and Wang Shiyuan1(1. Faculty of Electronic and information Engineering ,Southwest university, Chongqing {2.0715, china 2. school of Electronic and information Engineering, South china university of Technology, guangzhou 5106{2., china) Faculty of Electronic and information Engineering Southwest University Chongqing 400715 China school of Electronic and information Engineering South China University of Technology Guangzhou 510641 China

A non-periodic oscillatory behavior of the unscented Kalman filter (UKF) when used to filter noisy contaminated chaotic signals is reported. We show both theoretically and experimentally that the gain of the UKF may not converge or diverge but oscillate aperiodically. More precisely, when a nonlinear system is periodic, the Kalman gain and error covariance of the UKF converge to zero. However, when the system being considered is chaotic, the Kalman gain either converges to a fixed point with a magnitude larger than zero or oscillates aperiodically.

关键词： chaos unscented Kalman filter Lyapunov exponents aperiodicity.

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Optical pulse compression using a nonlinear optical loop mirror constructed from dispersion decreasing fiber

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Science china(Technological Sciences) 2004年第1期47卷 33-50页

作者： CAO Wenhua & LIU Songhaoschool of information, Wuyi {2., Jiangmen 52.02., china school for information and Optoelectronic Science and Engineering, South china Normal {2., guangzhou 510631, china 1. school of information Wuyi University 529020 Jiangmen China 2. school for information and Optoelectronic Science and Engineering South China Normal University 510631 Guangzhou China

A novel scheme to compress optical pulses is proposed and demonstrated numerically, which is based on a nonlinear optical loop mirror constructed from dispersion decreasing fiber (DDF). We show that, in contrast to the conventional soliton-effect pulse compression in which compressed pulses are always accompanied by pedestals and frequency chirps owning to nonlinear effects, the proposed scheme can completely suppress pulse pedestals and frequency chirps. Unlike the adiabatic compression technique in which DDF length must increase exponentially with input pulsewidth, the proposed scheme does not require adiabatic condition and therefore can be used to compress long pulses by using reasonable fiber lengths. For input pulses with peak powers higher than a threshold value, the compressed pulses can propagate like fundamental solitons. Furthermore, the scheme is fairly insensitive to small variations in the loop length and is more robust to higher-order nonlinear effects and initial frequency chirps than the adiabatic compression technique.

关键词： dispersion decreasing fiber (DDF), optical pulse compression, optical solitons.

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Estimation of underdetermined mixing matrix based on support vector machine

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Progress in Natural Science:Materials International 2007年第11期17卷 1363-1367页

作者： Yang Zuyuan and Xie Shengli(school of Electrics & information Engineering, South{2. university of Technology, {4. 51064.,{2.) school of Electrics & information Engineering South China University of Technology Guangzhou 510641 China

In underdetermined blind source separation (BSS), a novel algorithm based on extended support vector machine (SVM) is proposed to estimate the mixing matrix in this paper, including the number of the active sources. Instead of traditional clustering algorithms, it mainly takes the modulus of observations and the number in each direction of arrival, without any prior knowledge about the sources except for sparsity, and it is not sensitive to the initial values. Simulations are given to illustrate availability and robustness of our algorithm.

关键词： underdetermined BSS SVM clustering

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Linearly time-varying channel estimation and training power allocation for OFDM/MIMO systems using superimposed training

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Science china(information Sciences) 2011年第7期54卷 1456-1470页

作者： ZHANG Han 1,DAI XianHua 2.& Pan DaRu 1 1 school of Physics and Telecommunication Engineering,South china Normal {2.,guangzhou 510006,{4. 2.Department of information Science and Technology,SUN Yat-sen {2.,guangzhou 51002.,{4. 1. school of Physics and Telecommunication Engineering South China Normal University Guangzhou 510006 China2. Department of Information Science and Technology SUN Yat-sen University Guangzhou 510026 China

We address the problem of estimating the linearly time-varying (LTV) channel of orthogonal frequency division multiplexing (OFDM)/multiple-input multiple-output (MIMO) systems using superimposed training (ST).The LTV channel is modeled by truncated discrete Fourier *** on this model,a two-step approach is adopted to estimate the LTV channel over multiple OFDM *** also present performance analysis of the channel estimation and derive a closed-form expression for the channel estimation *** is shown that the estimation variances,unlike that of the conventional ST-based schemes,approach to a fixed lower-bound as the training length increases,which is directly proportional to information-pilot power *** wireless communication systems with a limited transmission power,we optimize the ST power allocation by maximizing the lower bound of the average channel *** results show that the proposed approach outperforms the frequency-division multiplexed training schemes.

关键词： OFDM/MIMO systems linearly time-varying channel estimation superimposed training training power allocation

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