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progress in Natural Science:Materials International 2007年第10期17卷 1147-1151页

作者： Liu Dan1,2 , Zhang Yong3.and Long Guilu1,2(1. Key Laboratory for Atomic and Molecular NanoSciences, and Department of physics, Tsinghua University, beijing 100084, china 2. Center of Quantum Information Science and technology, Tsinghua National Laboratory for information Science and technology, beijing 100084, china 3. institute of physics, School of Sciences, beijing University of posts and telecommunications, beijing 100876, china) Key Laboratory for Atomic and Molecular NanoSciences and Department of Physics Tsinghua University Beijing 100084 China Center of Quantum Information Science and technology Tsinghua National Laboratory for information Science and Technology Beijing 100084 China institute of physics School of Sciences Beijing University of Posts and Telecommunications Beijing 100876 China

We study the ground state entanglement in a three-qubit XY chain under the influence of a magnetization current. It is found that the ground state changes from a W state to a disentangled state as the magnetic field varies. When the Lagrange multiplier λ>3. namely under a strong magnetic current, the ground state holds onto a W state for a large range of the magnetic field strength. A phase transition to the magnetization-current phase occurs under a certain condition.

关键词： Heisenberg-XY chain magnetic-current phase transition.

Multiparty simultaneous quantum identity authentication with secret sharing

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Science china(physics,Mechanics & Astronomy) 2008年第3期51卷 321-327页

作者： YANG YuGuang1,2,WEN QiaoYan3.& ZHANG Xing4,5 1 College of Computer Science and technology,beijing University of technology,beijing 100022,china 2 State Key Laboratory of Information Security (Graduate University of the Chinese Academy of Sciences),beijing 100049,china 3.School of Science,beijing University of posts and telecommunications,beijing 100876,china 4 institute of Electronic technology,Information Engineering University,Zhengzhou 450004,china 5 Trusted Computing Laboratory,beijing University of technology,beijing 100022,china College of Computer Science technology Beijing University of Technology Beijing 100022 China State Key Laboratory of Information Security [Graduate University of the Chinese Academy of Sciences] Beijing 100049 China School of Science Beijing University of Posts telecommunications Beijing 100876 China institute of Electronic technology Information Engineering University Zhengzhou 450004 China Trusted Computing Laboratory Beijing University of Technology Beijing 100022 China

Two multiparty simultaneous quantum identity authentication (MSQIA) protocols based on secret sharing are presented. All the users can be authenticated by a trusted third party (TTp) simultaneously. In the first protocol,the TTp shares a random key K with all the users using quantum secret sharing. The ith share acts as the authentication key of the ith user. When it is necessary to perform MSQIA,the TTp generates a random number r secretly and sends a sequence of single photons encoded with K and r to all the users. According to his share,each user performs the corresponding unitary operations on the single photon sequence sequentially. At last,the TTp can judge whether the impersonator exists. The sec-ond protocol is a modified version with a circular structure. The two protocols can be efficiently used for MSQIA in a network. They are feasible with current technol-ogy.

关键词： quantum identity authentication secret sharing quantum cryptography

Jet formation and penetration mechanism of W typed shaped charge

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Acta Mechanica Sinica 2009年第1期25卷 107-120页

作者： Cheng Wang Fenglei Huang Jianguo Ning State Key Laboratory of Explosion Science and technology,beijing institute of technology, 100081 beijing, china State Key Laboratory of Explosion Science and technology Beijing Institute of Technology 100081 Beijing China

Existing classical shaped charges are well known for their longer jets capable of achieving large hole depth to hole diameter ratios in metallic targets. However, in some situations, there arises demand to obtain 1：1 ratio for hole depth to hole diameter which is beyond normal shaped charges capability. A new variant of shape charge, named W typed shape charge （WSC）, is proposed in this paper, which can meet the demand of 1：1 ratio, and is based on the geometry that can produce annular jets upon proper initiation scheme. In this paper, we present formation and penetration results of WSC based on three different schemes. We also show that not all WSC designs can form annular jets, only annularly initiated WSC, which also fulfils the ＂Internal-External Liners Equal-Impulse＂ criterion, has the capability to form annular jet. The experimental and numerical results show that when the ratio between annular initiation ring diameter and the charge diameter is 0.75, an annular jet is formed, which was also supported by high speed photographs performed in vacuum. 2D numerical simulations are performed with indigenously developed simulation software, where Eulerian approach with multi-material interface tracking algorithm is utilized, to find various mechanisms involved during jet formation process. The calculation results are found in good agreement with the experimental results, indicating that the interface treatment algorithm proposed in this paper can not only deal with large deformation problem, but also depict clearly the variation of materials interface. It is especially suitable for simulation of the process from liner collapse to formation of shaped charge jet.

关键词： WSC Annular jet Interface tracking Numerical simulation

An Application of Optimal preview Control in Terrain Following System

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Journal of Systems Engineering and Electronics 2002年第1期13卷 21-26页

作者： Li Dongmei Dept. of precision Instrument and Mechanics, Tsinghua University, beijing 100084, p.r.china Zhou Di, Hu Zhenkun & Hu Hengzhang Dept. of Control Science and Engineering, Harbin institute of {3., Harbin 150001, p.r.china Dept. of precision Instrument and Mechanics Tsinghua University Beijing 100084 P. R. China Dept. of Control Science and Engineering Harbin Institute of Technology Harbin 150001 P. R. China

An optimal preview method is applied to the design of terrain following controller for cruise missile. In this method, tracking errors and control increments are both considered in the quadratic cost function. Integrating the general optimal servo system with a preview feedforward compensation that feeds forward future command and future disturbance produces an optimal preview servo system. In the terrain following system, the flight altitude of the cruise missile is a command signal, and its future information can be known apriori. Hence, we have designed a terrain following controller with a basic state feedback and a feedforward compensation for future altitude information. Simulation results show that the performance of the terrain following system with such an optimal preview controller has been improved dramatically.

关键词： Cruise missile Terrain following preview control Optimal control Feedforward compensation.

Design of secure operating systems with high security levels

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Science in china(Series F) 2007年第3期50卷 399-418页

作者： QING SiHan1,2 & SHEN ChangXiang3.1 institute of Software, Chinese Academy of Sciences, beijing 100080, china 2 School of Software and Microelectronics, peking University, beijing 102600, china 3.institute of Computing technology, Navy, beijing 100841, china 1. institute of Software Chinese Academy of Sciences Beijing 100080 China 2. School of Software and Microelectronics Peking University Beijing 102600 China 3. institute of Computing technology Navy Beijing 100841 China

Numerous Internet security incidents have shown that support from secure operating systems is paramount to fighting threats posed by modern computing environments. Based on the requirements of the relevant national and international standards and criteria, in combination with our experience in the design and development of the ANSHENG v4.0 secure operating system with high security level （hereafter simply referred to as ANSHENG OS）, this paper addresses the following key issues in the design of secure operating systems with high security levels： security architecture, security policy models, and covert channel analysis. The design principles of security architecture and three basic security models： confidentiality, integrity, and privilege control models are discussed, respectively. Three novel security models and new security architecture are proposed. The prominent features of these proposals, as well as their applications to the ANSHENG OS, are elaborated. Cover channel analysis （CCA） is a well-known hard problem in the design of secure operating systems with high security levels since to date it lacks a sound theoretical basis and systematic analysis approach. In order to resolve the fundamental difficulties of CCA, we have set up a sound theoretical basis for completeness of covert channel identification and have proposed a unified framework for covert channel identification and an efficient backward tracking search method. The successful application of our new proposals to the ANSHENG OS has shown that it can help ease and speedup the entire CCA process.

关键词： secure operating systems with high security levels architecture security model covert channel analysis

Local segment-shared protection based on source egress gateway selection for multi-domain optical mesh networks

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Science china(Information Sciences) 2011年第2期54卷 227-235页

作者： ZHANG ShengFeng1,3. pENG YunFeng1,2, DU Shu1, YANG XiaoLong1,2 & LONG Keping1,2 1research Center for Optical Internet and Mobile Information Networks, University of Electronic Science and technology of china, Chengdu 61173., china 2{3. of Advanced Network technology and New Serives (ANTS), University of Science and technology beijing, beijing 100083. china 3.esearch Center for Optical Internet Networks, Chongqing University of posts and telecommunications, Chongqing 400065, china 1. research Center for Optical Internet and Mobile Information Networks University of Electronic Science and Technology of China Chengdu 611731 China3. Research Center for Optical Internet Networks Chongqing University of Posts and Telecommunications Chongqing 400065 China2. Institute of Advanced Network Technology and New Serives (ANTS) University of Science and Technology Beijing Beijing 100083 China

Survivability for multi-domain optical networks is becoming a key parameter due to expanding network. In order to provide the shared-path-protected lightpath in multi-domain optical mesh networks, we propose a protection solution, called GSLSSp. A new source egress gateway selecting mechanism is adopted in this solution. For each connection request, this mechanism can enable the source node to select a better egress gateway node to the destination domain and compute one inter-domain working path near the optimal path with the cooperating of this gateway node, under scalability and domain privacy constraint of multi-domain networks. And then one intra-domain link-disjoint local segment-backup path for each working-segment path is computed out in each single-domain passed by the working path. Simulation evaluation shows that the proposed scheme can provide 100% protection ability for multiple failures. Besides, it is effective in multi-domain path protection with more efficient resource utilization, lower blocking probabilities and less inter-domain cost than other schemes.

关键词： survivability optical mesh networks multi-domains multiple failures segment-shared protection

Augmented reality registration algorithm based on nature feature recognition

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Science china(Information Sciences) 2010年第8期53卷 1555-1565页

作者： CHEN Jing 1 , WANG YongTian 1,2 , GUO JunWei 1 , LIU Wei 1 , LIN JingDun 1 , XUE Kang 1 , LIU Yue 1 & DING GangYi 3. School of Optoelectronics, beijing institute of technology, beijing 100081, china 2 School of Computer Science and technology, beijing institute of technology, beijing 100081, china 3.School of Software, beijing institute of technology, beijing 100081, china 1. School of Optoelectronics Beijing Institute of Technology Beijing 100081 China2. School of Computer Science and Technology Beijing Institute of Technology Beijing 100081 China3. School of Software Beijing Institute of Technology Beijing 100081 China

This paper presents an improved key frame based augmented reality registration algorithm for real-time motion tracking in outdoor environment. In such applications, wide-baseline feature matching is a critical problem. In this paper, we apply randomized tree method to match key points extracted from the input image to those key frames as a classification problem. Extended Kalman filter is also utilized for jitter correction. A video see-through mobile augmented reality system is built for the on-site digital reconstruction of Yuanmingyuan Garden. Experimental results demonstrate that this algorithm is real-time, robust and effective for outdoor tracking.

关键词： outdoor augmented reality camera tracking randomized tree

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,{3. 2institute of Electronic technology,Information Engineering University,Zhengzhou 450004,{3. 3.2} University of posts and telecommunications,beijing 100190,{3. 4Graduate University,the Chinese Academy of Science,beijing 100049,{3. 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

relative position determination of a lunar rover using high-accuracy multi-frequency same-beam VLBI

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Science china(physics,Mechanics & Astronomy) 2010年第3期53卷 571-578页

作者： LIU QingHui1, CHEN Ming1, XIONG WeiMing2, QIAN ZhiHan1, LI JinLing1, HAO WangHong1,4, WANG GuangLi1, ZHENG WeiMin1, GUAN Di3. ZHU renJie1, WANG WeiHua1, ZHANG XiuZhong1, JIANG Dongrong1, SHU FengChun1, pING JinSong1 & HONG XiaoYu11 Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 20003., china 2 Center for Space Science and Applied research, Chinese Academy of Sciences, beijing 100190, china 3.Lunar Explorer Engineering General Department, Chinese Academy of Sciences, beijing 100012, china 4 beijing institute of tracking and telecommunications technology, beijing 100094, china 1. Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China2. Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100190 China4. Beijing Institute of Tracking and Telecommunications Technology Beijing 100094 China3. Lunar Explorer Engineering General Department Chinese Academy of Sciences Beijing 100012 China

Multi-frequency same-beam VLBI means that two explorers with a small separation angle are simultaneously observed with the main beam of receiving antennas. In the same-beam VLBI, the differential phase delay between two explorers and two receiving telescopes can be obtained with a small error of several picoseconds. The differential phase delay, as the observable of the same-beam VLBI, gives the separation angular information of the two explorers in the celestial sphere. The two-dimensional relative position on the plane-of-sky can thus be precisely determined with an error of less than 1 m for a distance of 3.8×105 km far away from the earth, by using the differential phase delay obtained with the four Chinese VLBI stations. The relative position of a lunar rover on the lunar surface can be determined with an error of 10 m by using the differential phase delay data and the range data for the lander when the lunar topography near the rover and the lander can be determined with an error of 10 m.

关键词： same-beam VLBI differential phase delay relative position determination lunar rover