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Investigation on the skewness for independent component analysis

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Science china(information Sciences) 2011年第4期54卷 849-860页

作者： LIU ZhiYong & QIAO Hong institute of Automation,chinese academy of Sciences,beijing 100190,china 1. institute of Automation Chinese Academy of Sciences Beijing 100190 China

Skewness has received much less attention than kurtosis in the independent component analysis (ICA).In particular,the skewness seems to become a useless statistics after the kurtosis related one-bit-matching theorem was ***,as the non-Gaussianity of one signal comes mainly from skewness,it is intuitively understandable that its recovery should not rely on *** this paper we discuss the skewness based ICA,and show that any probability density function (pdf) with non-zero skewness can be employed by ICA for the recovery of the source with non-zero skewness,without needing to consider the skewness *** observation together with the one-bit-matching theorem provides a basic guideline for the model pdf design in ICA algorithm.

关键词： independent component analysis skewness kurtosis one-bit-matching theorem

The roles of a decision support system in applying forest ecosystem management in Northeast china

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Science china(Technological Sciences) 2006年第z1期49卷 9-18页

作者： DAI Limin, ZHENG Bofu, Guofan Shao & ZHOU Li State Key Lab of Systems Ecology, Research Center for Eco-Environmental Sciences, chinese academy of Sciences, beijing 100085, china institute of Applied Ecology, chinese academy of Sciences, Shenyang 110016, china Department of forestry and Natural resources, Purdue University, West Lafayette, IN 47907, USA Graduate University of chinese academy of Sciences, beijing 100101, china 1. State Key Lab of Systems Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China2. Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China3. Department of Forestry and Natural Resources Purdue University West Lafayette IN 47907 USA4. Graduate University of Chinese Academy of Sciences Beijing 100101 China

forest ecosystems provide a variety of services and forest ecosystem management (FEM) is an effective approach to maximize the services. Because of the complexity of forest ecosystems, the applications of FEM can be facilitated with decision support systems (DSS) that recognize and incorporate ecological and socio-economic variables. With the rapid development of computation and information technologies, DSS have been advanced in many ways. Traditional forest management within a forestry unit in china is planned on a yearly basis. The planning itself remains primarily a verbal concept as there are no quantitative decision-support tools available to translate the concept into forest management actions. For the purposes of FEM at the management level, a forest management DFF, forestAR, has been developed under a framework of geographic information system (GIS) and forest models. The paper explained the intelligent modeling mechanisms and demonstrated how the applications of FEM can be strengthened with the applications of forestAR.

关键词： forest functions, forested landscapes, forest services, forest models, geographic information systems.

The correspondence between the concepts in description logics for contexts and formal concept analysis

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Science china(information Sciences) 2012年第5期55卷 1106-1122页

作者： MA Yue 1,2,SUI YueFei 1 & CAO CunGen 1 1 Key Laboratory of Intelligent information Processing,institute of Computing Technology,chinese academy of Sciences,beijing 100190,china 2 Graduate University of chinese academy of Sciences,beijing,china 1. Key Laboratory of Intelligent information Processing Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China

Formal concept analysis (FCA) and description logic (DL) are meant to be formalizations of concepts.A formal concept in the former consists of its intent and extent,where the intent is the set of all the attributes shared by each object in the extent of the concept,and the extent is the set of all the objects sharing each property in the intent of the concept.A concept in the latter formalization is simply a concept name,the interpretation of which is a subset of a *** consider the correspondence between concepts in both formalizations,a multi-valued formal context must be represented both as a knowledge base and as a model of the DL for contexts,where concepts are decomposed into tuple concepts C,interpreted as a set of tuples and value concepts V,interpreted as a set of attribute-value *** show that there is a difference between the interpretation of concepts R.V /R.C and the Galois connection between the extent/intent of formal concepts in *** to the Galois connection,there should be concepts of the form + R.V and + R.C inter-preted in FCA,and hence the logical language L for DL is extended to be L + together with + as a constructor so that + R.V and + R.C are well-defined ***,according to the interpretation in DL there should be pseudo concepts in FCA so that the interpretation of concepts R.V /R.C is the extent/intent of pseudo *** correspondence between formal concepts and concepts in L +,and between pseudo concepts and concepts in L are presented in this paper.

关键词： description logic formal concept analysis concept attribute/role

A novel logic-based automatic approach to constructing compliant security policies

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Science china(information Sciences) 2012年第1期55卷 149-164页

作者： BAO YiBao1,2,4,YIN LiHua1,FANG BinXing 1,3&GUO Li 1 1institute of Computing Technology,chinese academy of Sciences,beijing 100190,china 2institute of Electronic Technology,information Engineering University,Zhengzhou 450004,china 3beijing University of Posts and Telecommunications,beijing 100190,china 4Graduate University,the chinese academy of Science,beijing 100049,china 1. institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China2. Institute of Electronic Technology Information Engineering University Zhengzhou 450004 China4. Graduate University the Chinese Academy of Science Beijing 100049 China3. Beijing University of Posts and Telecommunications Beijing 100190 China

It is significant to automatically detect and resolve the incompliance in security *** existing works in this field focus on compliance verification,and few of them provide approaches to automatically correct the incompliant security *** paper proposes a novel approach to automatically transform a given security policy into a compliant *** security policy Π and delegation policy M declared by logic programs,the approach automatically rewrites Π into a new one ΠM which is compliant with M and is readable by the *** prove that the algorithm is sound and complete under noninterference ***,we show that the security policy query evaluation algorithm with conflict and unsettlement resolution still works very well on Π*** approach is automatic,so it doesn't require a administrator with excess *** this sense,our proposal can help us to save much manpower resource in security management and improves the security assurance abilities.

关键词： security policy rewriting logic program compliance

Positive Darwinian selection in human population:A review

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chinese Science Bulletin 2008年第10期53卷 1457-1467页

作者： WU DongDong1,3 & ZHANG YaPing1,2 1 State Key Laboratory of Genetic resources and Evolution, Kunming institute of Zoology, chinese academy of Sciences, Kunming 650223, china 2 Laboratory for Conservation and Utilization of Bio-resource, Yunnan University, Kunming 650091, china 3 Graduate University of chinese academy of Sciences, beijing 100049, china State Key Laboratory of Genetic resources and Evolution Kunming Institute of Zoology Chinese Academy of Sciences Kunming 650223 China Laboratory for Conservation and Utilization of Bio-resource Yunnan University Kunming 650091 China Graduate University of chinese academy of Sciences Beijing 100049 China

This paper reviews a large number of genes under positive Darwinian selection in modern human populations, such as brain development genes, immunity genes, reproductive related genes, perception receptors. The research on the evolutionary property of these genes will provide important insight into human evolution and disease mechanisms. With the increase of population genetics and comparative genomics data, more and more evidences indicate that positive Darwinian selection plays an indispensable role in the origin and evolution of human beings. This paper will also summarize the methods to detect positive selection, analyze the interference factors faced and make suggestions for further research on positive selection.

关键词：自然选择积极选择达尔文进化论人类学种群遗传

Characterization of plastic flow in two Zr-based bulk metallic glasses

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Science china(Technological Sciences) 2006年第4期49卷 414-424页

作者： XING Dongmei1,2, ZHANG Taihua1, LI Weihuo3 & WEI Bingchen3 1. State Key Laboratory of Nonlinear Mechanics (LNM), institute of Mechanics, chinese academy of Sci- ences, beijing 100080, china 2. College of Physics and Electronic information Science, Tianjin Normal University, Tianjin 300074, china 3. National Microgravity Laboratory, institute of Mechanics, chinese academy of Sciences, beijing 100080, china 1. State Key Laboratory of Nonlinear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China 2. College of Physics and Electronic information Science Tianjin Normal University Tianjin 300074 China 3. National Microgravity Laboratory Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

Plastic deformation behaviors of Zr65Al10Ni10Cu15 and Zr52.5Al10Ni10Cu15Be12.5 bulk metallic glasses (BMGs) are studied by using the depth-sensing nanoindentation, microindentation and uniaxial compression. The Be-containing BMG exhibits a signifi- cantly improved overall plastic strain compared with the Be-free alloy during compressive tests. Both BMGs show a loading-rate-dependent serrated flow during nanoindentation measurements, but the Be-containing alloy exhibits a much lower critical loading rate for the disappearance of the serration than the Be-free BMG. The shear band patterns de- veloped during plastic deformation are investigated by microindentation technique, wherein much higher shear band density is found in the Be-containing alloy than in the Be-free alloy, indicating an easier nucleation of shear bands in the former BMG. The dif- ference in the plastic deformation behavior of the two BMGs can be explained by a free volume model.

关键词： Bulk metallic glass, plastic deformation, shear band, nanoindentation.

On designated-weight Boolean functions with highest algebraic immunity

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Science china Mathematics 2010年第11期53卷 2847-2854页

作者： LIU MeiCheng1,3, DU YuSong2, PEI DingYi2 & LIN DongDai1 1The State Key Laboratory of information Security, institute of Software of chinese academy of Sciences, beijing 100190, china 2College of Mathematics and information Sciences, Guangzhou University, Guangzhou 510006, china 3Graduate University of chinese academy of Sciences, beijing 100049, china 1. The State Key Laboratory of information Security Institute of Software of Chinese Academy of Sciences Beijing 100190 China3. Graduate University of Chinese Academy of Sciences Beijing 100049 China2. College of Mathematics and Information Sciences Guangzhou University Guangzhou 510006 China

Algebraic immunity has been considered as one of cryptographically significant properties for Boolean functions. In this paper, we study ∑d-1 i=0 (ni)-weight Boolean functions with algebraic immunity achiev-ing the minimum of d and n - d + 1, which is highest for the functions. We present a simpler sufficient and necessary condition for these functions to achieve highest algebraic immunity. In addition, we prove that their algebraic degrees are not less than the maximum of d and n - d + 1, and for d = n1 +2 their nonlinearities equalthe minimum of ∑d-1 i=0 (ni) and ∑ d-1 i=0 (ni). Lastly, we identify two classes of such functions, one having algebraic degree of n or n-1.

关键词： cryptography Boolean function algebraic immunity algebraic degree nonlinearity

EXPONENTIAL STABILITY OF A REPARABLE MULTI-STATE DEVICE

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Journal of Systems Science & Complexity 2007年第3期20卷 437-443页

作者： Weiwei HU Houbao XU Jingyuan YU Guangtian ZHU beijing institute of information and Control Beijing 100037 China. Department of Mathematics Beijing Institute of Technology Beijing 100081 China. academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China.

The exponential stability of a multi-state device is discussed in this paper. We present that the Co-semigroup generated by the system operator is quasi-compact and irreducible. It is known that 0 is a simple eigenvalue of the system operator. In combination with this, we obtain that the time-dependent solution exponentially converges to the steady-state solution, which is the positive eigenfuction corresponding to the simple eigenvalue O.

关键词： C0-semigroup exponential stability irreducibility quasi-compact.

An improved imaging algorithm for fixed-receiver bistatic SAR

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Science china(information Sciences) 2010年第7期53卷 1461-1469页

作者： GENG XuPu1,2,3, HU YingHui1,2, YAN HongHui2 & WANG YanFei2 1Graduate School of the chinese academy of Sciences, beijing 100039, china 2institute of Electronics, chinese academy of Sciences, beijing 100190, china 3beijing institute of Environment Features, beijing 100854, china 1. Graduate School of the chinese academy of Sciences Beijing 100039 China2. Institute of Electronics Chinese Academy of Sciences Beijing 100190 China3. Beijing Institute of Environment Features Beijing 100854 China

Based on the signal model of fixed-receiver bistatic SAR, this paper analyzes the characteristics of azimuth-variant, which includes variation of range migration curve and variation of Doppler rate caused by different azimuth position of targets. Then, an extended nonlinear chirp scaling (NLCS) algorithm is proposed, with its flowchart and phase compensation functions being provided. Simulation results show that the algorithm is available for the characteristics of azimuth-variant of fixed-receiver bistatic SAR, and good focused radar images could be acquired.

关键词： synthetic aperture radar (SAR) bistatic SAR fixed-receiver characteristics of azimuth-variant range cell migration correction (RCMC)