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A distribution space for Hilbert transform and its applications

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science china {2. 2008年第12期51卷 2217-2230页

作者： YANG LiHua school of mathematics and Computing {2., sun yat-sen University, guangzhou 5102.5, china school of mathematics and Computing {2. Sun Yat-Sen University Guangzhou 510275 China

In this paper, a new distribution space is constructed and the definition of the classical Hilbert transform is extended to it. It is shown that is the biggest subspace of on which the extended Hilbert transform is a homeomorphism and both the classical Hilbert transform for L p functions and the circular Hilbert transform for periodic functions are special cases of the extension. Some characterizations of the space are given and a class of useful nonlinear phase signals is shown to be in . Finally, the applications of the extended Hilbert transform are discussed.

关键词： Hilbert transform distribution time-frequency analysis 44A15 46F12

Secure multi-party computation protocol for sequencing problem

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science china(Information sciences) 2011年第8期54卷 1654-1662页

作者： TANG ChunMing 1,2.SHI GuiHua 1 & YAO ZhengAn 3 1 school of mathematics and Information {2.,guangzhou University,guangzhou 510006, china 2.tate Key Laboratory of Information Security, Institute of Software {2.,Chinese Academy of {2.s,Beijing 100080,china 3 school of mathematics and computational {2.,sun yat-sen University,guangzhou 5102.5,china 1. school of mathematics and Information {2. Guangzhou University Guangzhou 510006 China2. State Key Laboratory of Information Security Institute of Software Science Chinese Academy of Sciences Beijing 100080 China3. School of Mathematics and Computational Science Sun Yat-Sen University Guangzhou 510275 China

In the field of multi-party computation,an important problem is how to construct an efficient and secure multi-party computation protocol for certain specific *** the present study,we make use of a secret sharing scheme to construct an efficient and secure multi-party computation protocol for sequencing *** protocols are perfectly secure against both a passive adversary that can corrupt at most t (n-1)/2.participants, and an active adversary that can corrupt at most t < n/3 *** simplest sequencing problem is the Millionaires' problem.

关键词： secure multi-party computation sequencing problem secret sharing

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,{2. yat-sen University,guangzhou 5102.5,china 2.Guangdong Province Information Security Key Laboratory,{2. yat-sen University,guangzhou 5102.5,china 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

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, {2. yat-sen University, guangzhou 5102.5, china 2. Guangdong Province Key Laboratory of Information Security, guangzhou 5102.5, china 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.

Calibration based universal JPEG steganalysis

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science in china(Series F) 2009年第2期52卷 260-268页

作者： HUANG FangJun1,2.& HUANG JiWu1,2.1 school of Information science and Technology,{2. yat-sen University,guangzhou 5102.5,china 2.Guangdong Key Lab. of Information Security Technology,{2. yat-sen University,guangzhou 5102.5,china school of Information science and Technology Sun Yat-Sen University Guangzhou 510275 China Guangdong Key Lab. of Information Security Technology Sun Yat-Sen University Guangzhou 510275 China

For steganalysis of JPEG images, features derived in the embedding domain appear to achieve a preferable performance. However, with the existing JPEG steganography, the minor changes due to the hidden secret data are not easy to be explored directly from the quantized block DCT （BDCT） coefficients in that the energy of the carrier image is much larger than that of the hidden signal. In this paper, we present an improved calibration-based universal JPEG steganalysis, where the microscopic and macroscopic calibrations are combined to calibrate the local and global distribution of the quantized BDCT coefficients of the test image. All features in our method are generated from the difference signal be- tween the quantized BDCT coefficients of the test image and its corresponding microscopic calibrated image, or calculated as the difference between the signal extracted from test image and its corresponding macroscopic calibrated image. The extracted features will be more effective for our classification. Moreover, through using the Markov empirical transition matrices, both magnitude and sign dependencies along row scanning and column scanning patterns existed in intra-block and inter-block quantized BDCT coefficients are employed in our method. Experimental results demonstrate that our proposed scheme outperforms the best effective JPEG steganalyzers having been presented.

关键词： JPEG steganography steganalysis microscopic calibration macroscopic calibration

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, {2. yat-sen University, guangzhou 5102.5, china 2.Guangdong Key Laboratory of Information Security Technology, guangzhou 5102.5, china 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

Investigation of thermoluminescence in Li_2._4O_7 phosphors doped with Cu, Ag and Mg

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science china(Physics,Mechanics & Astronomy) 2007年第3期50卷 311-320页

作者： XIONG ZhengYe1,2. TANG Qiang2.& ZHANG ChunXiang2.1 College of science, Guangdong Ocean University, Zhanjiang 52.088, china {2. of Physics science and Engineering, sun yat-sen University, guangzhou 5102.5, china 1. College of science Guangdong Ocean University Zhanjiang 524088 China 2. school of Physics science and Engineering Sun Yat-sen University Guangzhou 510275 China

Li2.4O7 （LBO）:Cu,Ag,Mg phosphors have been prepared by the sintering technique. The roles of the Ag and Mg dopants in the phosphors have been studied using the methods of thermoluminescence （TL） glow curves and TL... 详细信息

Li2./sub>B4O7 （LBO）:Cu,Ag,Mg phosphors have been prepared by the sintering technique. The roles of the Ag and Mg dopants in the phosphors have been studied using the methods of thermoluminescence （TL） glow curves and TL 3D spectra. The results indicated that proper concentrations of Ag and Mg can enhance the TL of LBO:Cu. It was also indicated that the intensity of TL peak at 130℃ is reduced with the in- creasing Ag concentration, and enhanced with the increasing Mg concentration. From the TL 3D spectra, three emission bands （λ1 = 42. nm, λ2.= 380 nm, λ3 = 350 nm） were observed: the intensity of low energy emission band is reduced and that of the high energy is enhanced with the increasing dopant Ag; on the contrary, the intensity of low energy emission band is enhanced and that of the high energy one is reduced with the increasing dopant Mg.

关键词： thermoluminescence spectra borate lithium

High norbornene incorporation in ethylene-norbornene copolymerization with a bis(α-alkyloxoimine) titanium-MAO catalyst

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science china Chemistry 2010年第8期53卷 1634-1640页

作者： GAO HaiYang1,2.HU Hao1 & WU Qing1,2.1Institute of Polymer science,school of Chemistry and Chemical Engineering,{2. yat-sen (Zhongshan) University,guangzhou 5102.5,china 2.ey Laboratory for Polymeric Composite and Functional Materials of Ministry of Education {2. yat-sen (Zhongshan) University,guangzhou 5102.5,china 1. Institute of Polymer science School of Chemistry and Chemical Engineering Sun Yat-Sen (Zhongshan) University Guangzhou 510275 China2. Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education Sun Yat-Sen (Zhongshan) University Guangzhou 510275 China

A novel bis(α-alkyloxoimine) titanium(IV) complex was synthesized and used as a catalyst precursor to catalyze homo-and copolymerization of ethylene and *** titanium complex activated with methylalumoxane exhibits good activities for the homopolymerizations of ethylene and norbornene under high temperature to produce high-molecular-weight linear polyethylene and vinyl-type polynorbornene,***-norbornene copolymers with high molecular weight can also be produced by this *** incorporation of norbornene from 0 to 76 mol% in the copolymers can be controlled by varying the charged norbornene.13C NMR analyses show that the microstructures of the ethylene-norbornene copolymers with low norbornene incorporation are predominantly alternated and isolated norbornene units,while those with high norbornene incorporation are random polymers containing long norbornene sequences.

关键词： catalyst ethylene norbornene polymerization copolymerization

Biorthogonal multiple wavelets generated by vector refinement equation

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science china {2. 2007年第7期50卷 1015-1025页

作者： Song LI~(1+) Jun XIAN~2.1 Department of mathematics,Zhejiang University,Hangzhou 31002.,china 2.Department of mathematics,sun yat-sen University,guangzhou 5102.5,china 1. Department of mathematics Zhejiang University Hangzhou 310027 China 2. Department of mathematics Sun Yat-Sen University Guangzhou 510275 China

Biorthogonal multiple wavelets are generated from refinable function vectors by using the multiresolution analysis. In this paper we provide a general method for the construction of compactly supported biorthogonal multiple wavelets by refinable function vectors which are the solutions of vector refinement equations of the form $$\varphi (x) = \sum\limits_{\alpha \in \mathbb{Z}^s } {a(\alpha )\varphi (Mx - \alpha ), x \in \mathbb{R}^s } ,$$ where the vector of functions ? = (? 1, …, ? r)T is in $(L_2.(\mathbb{R}^s ))^r ,a = :(a(\alpha ))_{\alpha \in \mathbb{Z}^s } $ is a finitely supported sequence of r × r matrices called the refinement mask, and M is an s × s integer matrix such that lim n→∞ M ?n = 0. Our characterizations are in the general setting and the main results of this paper are the real extensions of some known results.

关键词： refinement equation biorthogonal multiple wavelets refinable function vector 42.40 41A10 41A15 41A2.