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Spray and forward:Efficient routing based on the Markov location prediction model for DTNs

Science China(information sciences) 2012年第2期55卷 433-440页

作者： DANG Fei1,YANG XiaoLong1,2.& LONG KePing2.1 research center for Optical Internet and Mobile {2. Networks(COIMIN),University of Electronic Science and {3. of China,Chengdu 61173.,China 2.School of Computer and Communications Engineering,University of Science and {3. beijing,beijing 100083.China research center for Optical Internet and Mobile {2. Networks (COIMIN) University of Electronic Science and Technology of China Chengdu China School of Computer and Communications Engineering University of Science and Technology Beijing Beijing China

Typical delay tolerant networks(DTNs)often suffer from long and variable delays,frequent connectivity disruptions,and high bit error *** DTNs,the design of an efficient routing algorithm is one of the key *** existing methods improve the accessibility probability of the data transmission by transmitting many copies of the packet to the network,but they may cause a high network *** address the tradeoff between a successful delivery ratio and the network overhead,we propose a DTN routing algorithm based on the Markov location prediction model,called the spray and forward routing algorithm(SFR).Based on historical information of the nodes,the algorithm uses the second-order Markov forecasting mechanism to predict the location of the destination node,and then forwards the data by greedy routing,which reduces the copies of packets by spraying the packets in a particular *** contrast to a fixed mode where a successful-delivery ratio and routing overhead are contradictory,a hybrid strategy with multi-copy forwarding is able to reduce the copies of the packets efficiently and at the same time maintain an acceptable successful-delivery *** simulation results show that the proposed SFR is efficient enough to provide better network performance than the spray and wait routing algorithm,in scenarios with sparse node density and fast mobility of the nodes.

关键词： delay tolerant networks spray and forward Markov position prediction routing algorithm

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Conjugate adjoining problem in braid groups and new design of braid-based signatures

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Science China(information sciences) 2010年第3期53卷 524-536页

作者： WANG LiCheng1,2. WANG LiHua2. CAO ZhenFu3. YANG YiXian1 & NIU XinXin1 information {2. {2., State Key Laboratory of Networking and Switching {3., beijing University of Posts and Telecommunications, beijing 100876, China 2.ational Institute of information and Communications {3., Tokyo 184-8795, Japan 3.rusted Digital {3. Laboratory, Shanghai Jiao Tong University, Shanghai 2.02.0, China information security {2. State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing China National Institute of information and Communications technology Tokyo Japan Trusted Digital technology Laboratory Shanghai Jiao Tong University Shanghai China

The development of quantum computation casts serious threats to the securities of most existing public-key cryptosystems. Braid-based cryptography is one of the alternatives that have potential advantages in resisting quantum attacks. In this paper, the state of the art of braid cryptography is surveyed, and then a new cryptographic problem-conjugate adjoining problem related to braid groups is proposed. Based on this problem, we design a new braid-based signature scheme. This scheme is efficient and provably secure in the random oracle model. Further, we present the comparison between braid-based signatures and RSA-based ones. The signing process of the braid-based schemes is more efficient than that of RSA-based ones, while the verifying process of the braid-based ones is observably slow. Hence, braid-based signatures are suitable for scenarios where the signing process has to be as quick as possible but delays are permitted in the verifying process, for example, in off-line e-cash systems. The key sizes in braid-based schemes are considerably large-about 2. bits in the case of secret keys and 12. bits in the case of public keys. However, braid operations are much simpler and more efficient than modular exponential operations. Therefore, braid-based schemes can be embedded into devices with low computational ability and large memory space. The capability of braid cryptosystems to resist currently known quantum attacks is also discussed from the perspective of hidden subgroup problems.

关键词： braid group conjugate adjoining problem digital signature provable security resistance to quantum attack

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Multi-scale sparse feature point correspondence by graph cuts

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Science China(information sciences) 2010年第6期53卷 1224-1232页

作者： ZHANG Hong 1 , MU Ying 1 , YOU YuHu 2.& LI JunWei 3.1 Image Processing center, Beihang University, {2. 100191, China 2.{2. {3. Institute of Special Electromechanical technology, {2. 100012. China 3.National Key Laboratory on Optical Features of Environment and Target, {2. 100854, China Image Processing center Beihang University Beijing China beijing research Institute of Special Electromechanical {2. Beijing China National Key Laboratory on Optical Features of Environment and Target Beijing China

This paper presents a global stereo sparse matching technique based on graph cut theory to obtain accurate correspondence of stereo point pair in vision measurement ***, in order to obtain accurate location of feature points, a new multi-scale corner detection algorithm is proposed where wavelet coefficients are used to determine feature points by calculating an auto-correlation matrix.A sparse graph is constructed based on the feature points according to the graph cut ***, the feature point correspondence problem is transformed into a labeling problem in the sparse graph which can be solved by energy ***-scale analysis is utilized to improve the precision of matching *** was found that the use of sparse feature points in the construction of the graph can lead to both a simple graph structure and a reduced computational *** was also found that node labeling in the graph can be performed using fewer disparity values instead of all disparity *** experimental results show that the new global stereo sparse matching technique can obtain more accurate results than the existing techniques.

关键词： multi-scale feature point extraction graph cut theory stereo correspondence sparse point matching

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On the number of rotation symmetric Boolean functions

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Science China(information sciences) 2010年第3期53卷 537-545页

作者： FU ShaoJing1, LI Chao1,2.& QU LongJiang1,3.1Science College of National University of Defense technology, Changsha 410073. China 2.tate Key Laboratory of information {2., {3. 10003., China 3.ational Mobile Communications research Laboratory, Southeast University, Nanjing 2.0096, China Science College of National University of Defense technology Changsha China State Key Laboratory of information security Beijing China National Mobile Communications research Laboratory Southeast University Nanjing China

Rotation symmetric Boolean functions (RSBFs) have been used as components of different cryptosystems. This class of functions are invariant under circular translation of indices. In this paper, we investigated balanced RSBFs and 1st order correlation immune RSBFs. Based on constructive techniques, we give an accurate enumeration formula for n-variable balanced RSBFs when n is a power of a prime. Furthermore, an original and efficient method to enumerate all n-variable (n prime) 1st order correlationimmune functions is presented. The exact number of 1st order correlation immune RSBFs with 11 variables is 692.04715655047882.2.52.03.412.764511077684773.0552.800 and the number of 13.variables has 189 digits. Then for more variables, we also provide a significant lower bound on the number of 1st order correlation immune RSBFs.

关键词： cryptography rotation symmetry correlation immunity balancedness

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research of the Gas-solid Flow Character Based on the DEM Method

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Journal of Thermal Science 2011年第6期20卷 521-526页

作者： Xueyao Wang and Yunhan Xiao research center for Clean Energy and Power,Chinese {2. of {3. Key Laboratory of Advanced Energy and Power,Chinese {2. of {3. (Institute of Engineering Thermophysics),beijing,100190,China research center for Clean Energy and Power Chinese Academy of Sciences Beijing China Key Laboratory of Advanced Energy and Power Chinese Academy of Sciences (Institute of Engineering Thermophysics) Beijing China

Numerical simulation of gas-solid flow behaviors in a rectangular fluidized bed is carried out three dimensionally by the discrete element method (DEM).Euler method and Lagrange method are employed to deal with the gas phase and solid phase *** collided force among particles,striking force between particle and wall,drag force,gravity,Magnus lift force and Saffman lift force are considered when establishing the mathematic ***-sphere model is used to describe the collision of *** addition,the Euler method is also used for modeling the solid phase to compare with the results of *** flow patterns,particle mean velocities,particles' diffusion and pressure drop of the bed under typical operating conditions are *** results show that the DEM method can describe the detailed information among particles,while the Euler-Euler method cannot capture the micro-scale *** matter which method is used,the diffusion of particles increases with the increase of gas *** the gathering and crushing of particles cannot be simulated,so the energy loss of particles' collision cannot be calculated and the diffusion by using the Euler-Euler method is *** addition,it is shown by DEM method,with strengthening of the carrying capacity,more and more particles can be schlepped upward and the dense suspension upflow pattern can be ***,the results given by the Euler-Euler method are not consistent with the real situation.

关键词： DEM gas-solid flow numerical simulation

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information content security on the Internet:the control model and its evaluation

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Science China(information sciences) 2010年第1期53卷 30-49页

作者： FANG BinXing1, GUO YunChuan2.3.& ZHOU Yuan4 1School of Computer, beijing University of Posts and Telecommunications, beijing 10002., China 2.nstitute of Computing {2., Chinese {3. of sciences, beijing 100190, China 3.raduate University of Chinese {3. of sciences, beijing 100049, China 4National Computer Network Emergency Response Technical Team/Coordination center of China, beijing 10002., China School of Computer Beijing University of Posts and Telecommunications Beijing China Institute of Computing technology Chinese Academy of Sciences Beijing China Graduate University of Chinese academy of sciences Beijing China National Computer Network Emergency Response Technical Team/Coordination center of China Beijing China

Flooding of harmful information on the Internet seriously endangers the physiological and mental health of teenagers. Due to the user-friendliness of the Internet as well as the difficulty in the authentication for the access of specific categories of information, curbing the transmission of harmful information, i.e., assuring the information content security (ICS), has become a reasonable yet challenging alternative. At present, there is an urgent need to develop a systematic model that can effectively carry out the curbing. In fact, curbing the transmission of harmful information by way of filtering can be modeled by access control. In the paper, based on the three core-elements of communication, namely, "Who communicates with whom", "How do they communicate" and "What is the content of communication", we propose a control model, called ICCON. Unlike the existing access control, the reference monitor (RM) of our model is placed in the transmission channel, and moreover, an evaluation frame is proposed, through which the effectiveness of the RM in controlling information transmission on the Internet can be quantitatively evaluated.

关键词： content security access control quantitative evaluation

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Studies and advances on joint source-channel encoding/decoding techniques in flow media communications

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Science China(information sciences) 2010年第1期53卷 1-17页

作者： TU GuoFang1, LIU JianJun1, ZHANG Can1,2. GAO ShaoShuai3.& LI ShiDong4 1School of information Science and Engineering, Graduate University of Chinese {2. of {2., {3. 100049, China 2.tate Key Laboratory of information security, Graduate University of Chinese {2. of {2., {3. 100049, China 3.ational Institute of Standards and technology, Gaithersburg, MD 2.899, USA, 4Department of Mathematics, San Francisco State University, San Francisco, CA 9413., USA School of information Science and Engineering Graduate University of Chinese Academy of Sciences Beijing China State Key Laboratory of information security Graduate University of Chinese Academy of Sciences Beijing China National Institute of Standards and technology Gaithersburg USA Department of Mathematics San Francisco State University San Francisco USA

Joint source-channel coding/decoding (JSCC/JSCD) techniques in flow media communications have become a state-of-the-art and one of the challenging research subjects in the spatial communication area. They have great application prospective and deep impact in various manned space flights, satellite missions, mobile radio communications and deep-space explorations. In the last few years, there have been influential achievements in JSCC/JSCD studies. This paper aims at an introduction to the basic principles of joint source-channel optimal design. A general summarization and classification for various existing JSCC/JSCD methods is addressed. Also presented is a JSCD scheme based on variable-length coding, capable of providing reliable resolutions for flow media data transmission in spatial communications.

关键词： joint source-channel coding/decoding rate allocation variable-length coding/decoding iterative decoding

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Competent predicate abstraction in model checking

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Science China(information sciences) 2011年第2期54卷 258-267页

作者： LI Li1,2.3. SONG XiaoYu4, GU Ming2.3.& LUO XiangYu2.3.1Department of Computer Science & technology, Tsinghua University, beijing 100084, China 2.ey Laboratory for {2. System {3., Ministry of Education of China, beijing 100084, China 3.chool of Software, Tsinghua University, beijing 100084, China 4Department of ECE, Portland State University, Portland, Oregon 972.7, USA Department of Computer Science & technology Tsinghua University Beijing China Key Laboratory for information System security Ministry of Education of China Beijing China School of Software Tsinghua University Beijing China Department of ECE Portland State University Portland USA

The paper presents a new approach to computing the abstract state and a maximum weight heuristic method for finding the shortest counter-example in verification of imperative programs. The strategy is incorporated in a verification system based on the counterexample-guided abstraction refinement method. The proposed method slashes both the size of the abstract state space and the number of invokes of a decision procedure. A number of benchmarks are employed to evaluate the effectiveness of the approach.

关键词： program model checking predicate abstraction weight heuristic

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ON DECORRELATED FAST CIPHER

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Journal of Electronics(China) 2000年第1期17卷 94-96页

作者： Wu Wenling Li Bao Feng Denguo Qing Sihan(Engineering research center for {2. {3. technology,Chinese academy of sciences, beijing 100080)

Decorrelated Fast Cipher(DFC) is a candidate for the Advanced Encryption Standard (AES). It is shown that the cryptographic properties of the confusion permutation of DFC are weak in this paper. With the same F-function of DFC, a Feistel cipher VDFC which has no resistance against differential cryptanalysis is constructed. This demonstrates the importance of the key addition into DFC sufficiently. As a result, DFC may not be qualified candidate for the AES.

关键词： Round function Permutation Differential cryptanalysis Nonlinearity

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research on trusted computing and its development

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Science China(information sciences) 2010年第3期53卷 405-433页

作者： SHEN ChangXiang1, ZHANG HuanGuo1?, WANG HuaiMin3. WANG Ji3. ZHAO Bo2. YAN Fei2. YU FaJiang2. ZHANG LiQiang2.& XU MingDi2.{2. University of technology, {2. 10012., China 2.chool of Computer, Wuhan University, Key Laboratory of Aerospace {3. security and Trusted Computing of Ministry of Education, Wuhan 43.072. China 3.chool of Computer, National University of Defence technology, Changsha 43.074, China beijing University of technology Beijing China School of Computer National University of Defence Technology Changsha China Key Laboratory of Aerospace information security and Trusted Computing of Ministry of Education School of Computer Wuhan University Wuhan China

Trusted computing is a novel technology of information system {2.. It has become a new tide in worldwide information {2. area and achieved inspiring accomplishment. In China, the initiative research of trusted computing is not late, and the achievements are plentiful and substantial. Our country is in the front rank of the world in trusted computing. This paper comprehensively illustrates the recent development in theory and technology of trusted computing, introduces some improvements in trusted computing in our country, and proposes our opinions and viewpoints towards the existing problems in trusted computing and its future development.

关键词： information security trusted computing trusted computing platform trustworthy software trusted network connection

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