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

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 Security Center, State Key Laboratory of Networking and Switching technology, Beijing university of posts and {3., Beijing 100876, china 2National Institute of Information and Communications technology, Tokyo 184-8795, Japan 3.rusted Digital technology Laboratory, Shanghai Jiao Tong university, Shanghai 200240, china 1. Information Security Center State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China2. National Institute of Information and Communications Technology Tokyo 184-8795 Japan3. Trusted Digital Technology Laboratory Shanghai Jiao Tong University Shanghai 200240 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 2K bits in the case of secret keys and 12K 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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P2P traffic optimization

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science china(Information sciences) 2012年第7期55卷 1475-1492页

作者： ZHANG GuoQiang 1,2 ,TANG MingDong 3.,CHENG SuQi 2,4 ,ZHANG GuoQing 2 ,SONG HaiBin 5 ,CAO JiGuang 6 & YANG Jing 7 1 school of computer science and {3.,Nanjing Normal university,Nanjing 210046,china 2 Institute of Computing {3.,Chinese Academy of sciences,Beijing 100190,china 3.school of computer science and Engineering,Hunan university of science and {3.,Xiangtan 411201,china 4 Graduate university of Chinese Academy of sciences,Beijing 100190,china 5 Nanjing R&D Center,Huawei Technologies,Nanjing 210012,china 6 china Academy of Telecommunication Research of MIIT,Beijing 100191,china 7 china Mobile Research Institute,Beijing 100053.china 1. school of computer science and {3. Nanjing Normal University Nanjing 210046 China2. Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China3. School of Computer Science and Engineering Hunan University of Science and Technology Xiangtan 411201 China4. Graduate University of Chinese Academy of Sciences Beijing 100190 China5. Nanjing R&D Center Huawei Technologies Nanjing 210012 China6. China Academy of Telecommunication Research of MIIT Beijing 100191 China7. China Mobile Research Institute Beijing 100053 China

Peer-to-peer (P2P) based content distribution systems have emerged as the main form for content distribution on the Internet,which can greatly reduce the distribution cost of content providers and improve the overall system ***,the mismatch between the overlay and underlay networks causes large volume of redundant traffic,which intensifies the tension between P2P content providers and ***,how to efficiently use network resources to reduce the traffic burden on the ISPs is crucial for the sustainable development of P2P *** paper surveys the state-of-art P2P traffic optimization technologies from three perspectives:P2P cache,locality-awareness and data *** details,comparison between these technologies and their applicabilities are presented,followed by a discussion of the issues that remain to be addressed and the direction of future content distribution research.

关键词： P2P traffic localization P2P traffic optimization P2P cache locality-awareness network coding content-centric network

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The optimization of replica distribution in the unstructured overlays

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science china(Information sciences) 2012年第3期55卷 714-722页

作者： FENG GuoFu1,2 , LI WenZhong2, LU SangLu2, CHEN DaoXu2 & BUYYA Rajkumar3.1school of Information science, Nanjing Audit university, Nanjing 210029,{3. 2State Key Laboratory of Novel Software technology, Nanjing university, Nanjing 210093.{3. 3.epartment of computer science and Software Engineering, The university of Melbourne, Victoria 3.10, Australia 1. school of Information science Nanjing Audit University Nanjing 210029 China2. State Key Laboratory of Novel Software Technology Nanjing University Nanjing 210093 China3. Department of Computer Science and Software Engineering The University of Melbourne Victoria 3010 Australia

Replication is a widely used technique in unstructured overlays to improve content availability or system performance. A fundamental question often addressed by previous work focused on: how many replicas ought to be allocated for each data item given the fixed query rates and limited storage capability? In this paper, we have put forth two optimal replica distributions to achieve the highest success rate and the lowest message consumption. Especially, we have investigated the influence of item size on replica distribution. Our results show that Square-Root Replication, which is traditionally considered to be optimal, is not always the best choice. Our study offers a new deep understanding of resource managment in self-organized unstructured overlays.

关键词： unstructured overlay item size distribution query rate success rate expected search size

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Key technologies of new malicious code developments and defensive measures in communication networks

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The Journal of china Universities of posts and telecommunications 2010年第4期17卷 69-73页

作者： LI Peng,WANG Ru-chuan ,ZHANG Wei College of computer,Nanjing university of posts and {3.,Nanjing 210003.china [a] College of computer Nanjing University of Posts telecommunications Nanjing 210003 China

This article is focused on analyzing the key technologies of new malicious code and corresponding defensive measures in the large-scale communication networks. Based on description of the concepts and development of the malicious code, the article introduces the anti-analysis technology, splitting and inserting technology, hiding technology, polymorph virus technology, and auto production technology of the malicious code trends with intelligence, diversity and integration. Following that, it summarizes the security vulnerabilities of communication networks from four related layers aspects, according to the mechanisms of malicious code in the communication networks. Finally, it proposes rapid response disposition of malicious code attacks from four correlated steps： building up the network node monitoring system, suspicious code feature automation analysis and extraction, rapid active malicious code response technique for unknown malicious code, and malicious code attack immunity technique. As a result, it actively defenses against the unknown malicious code attacks and enhances the security performance of communication networks.

关键词： network security malicious code network attack and defense malicious code defense

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A novel evolutionary algorithm for global numerical optimization with continuous variables

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Progress in Natural science:Materials International 2008年第3期18卷 345-351页

作者： Wenhong Zhaoa,b, Wei Wang a, Yuping Wang a, a school of computer science and {3., Xidian university, Xi’an 710071, china b Faculty of science, Xidian university, Xi’an 710071, china school of computer science and {3. Xidian University Xi’an 710071 China Faculty of science Xidian University Xi’an 710071 China

Evolutionary algorithms (EAs) are a class of general optimization algorithms which are applicable to functions that are multimodal, non-differentiable, or even discontinuous. In this paper, a novel evolutionary algorithm is proposed to solve global numerical optimiza- tion with continuous variables. In order to make the algorithm more robust, the initial population is generated by combining determinate factors with random ones, and a decent scale function is designed to tailor the crossover operator so that it can not only find the decent direction quickly but also keep scanning evenly in the whole feasible space. In addition, to improve the performance of the algorithm, a mutation operator which increases the convergence-rate and ensures the convergence of the proposed algorithm is designed. Then, the global convergence of the presented algorithm is proved in detail. Finally, the presented algorithm is executed to solve 24 benchmark problems, and the results show that the convergence-rate of the proposed algorithm is much faster than that of the compared algorithms.

关键词： Evolutionary algorithm Decent scale function Global numerical optimization Global convergence

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Study of Cross-Media Topic Analysis Based on Visual Topic Model

Study of Cross-Media Topic Analysis Based on Visual Topic Mo...

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第24届中国控制与决策会议

作者： Yipeng Zhou 1,2 , Meiyu Liang 3., Junping Du 3.1. school of computer science and Information Engineering, Beijing {3. and Business university, Beijing, 100048, china2. school of Information, Renmin university of china, Beijing, 100872, china 3. Beijing Key Laboratory of Intelligent telecommunications Software and Multimedia, Beijing university of posts and telecommunications, Beijing, 100876, china

Research on cross-media topic analysis methods, which utilize semantic of multimedia data to describe topics of cross-media documents. As the emerge of food safety related multimedia data, topic analysis based on single media data can’t obtain full topics, causing the problem of inadequacy of semantic. A cross-media topic analysis framework is proposed in this paper. Firstly, generative methods are used to get semantic of text and image data respectively. Then a visual topic learning algorithm is presented to construct visual topic model and map visual data to text topics. This method can solve the problem of consistent semantic description of cross-media data. On this basis, food safety topic tracking is achieved and experiment results also show its effectiveness.

关键词： Cross-media Topic analysis Visual topic Food safety

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EXIT analysis of M-algorithm based MIMO detectors and LDPC code design optimization

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science in china(Series F) 2009年第12期52卷 2248-2258页

作者： YOU MingHou1,2, TAO XiaoFeng1,2, CUI QiMei1,2 & ZHANG Ping1,2 1 Wireless technology Innovation Institute, Beijing university of posts and {3., Beijing 100876, china 2 Key Laboratory of Universal Wireless Communications, (Beijing university of posts and {3.), Ministry of Education, Beijing 100876, china Wireless technology Innovation Institute Beijing University of Posts and Telecommunications Beijing 100876 China Key Laboratory of Universal Wireless Communications (Beijing University of Posts and Telecommunications) Ministry of Education Beijing 100876 China

This paper investigates joint design and optimization of both low density parity check （LDPC） codes and M-algorithm based detectors including iterative tree search （ITS） and soft-output M-algorithm （SOMA） in multiple-input multiple-output （MIMO） systems via the tool of extrinsic information transfer （EXIT） charts. First, we present EXIT analysis for ITS and SOMA. We indicate that the extrinsic information transfer curves of ITS obtained by Monte Carlo simulations based on output log-likelihood rations are not true EXIT curves, and the explanation for such a phenomenon is given, while for SOMA, the true EXIT curves can be computed, enabling the code design. Then, we propose a new design rule and method for LDPC code degree profile optimization in MIMO systems. The algorithm can make the EXIT curves of the inner decoder and outer decoder match each other properly, and can easily attain the desired code with the target rate. Also, it can transform the optimization problem into a linear one, which is computationally simple. The significance of the proposed optimization approach is validated by the simulation results that the optimized codes perform much better than standard non-optimized ones when used together with SOMA detector.

关键词： MIMO systems iterative receiver LDPC codes code optimization EXIT charts M-algorithm

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Parameter identification theory of a complex model based on global optimization method

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science china(Physics,Mechanics & Astronomy) 2008年第11期51卷 1722-1732页

作者： QU Jie1, JIN QuanLin2 & XU BingYe3.1 College of Automotive Engineering, South china university of technology, Guangzhou 510640, china 2 Beijing Research Institute of Mechanical and Electrical technology, Beijing 100083. china 3.Department of Engineering Mechanics, Tsinghua university, Beijing 100084, china 1. College of Automotive Engineering South China University of Technology Guangzhou 510640 China 2. Beijing Research Institute of Mechanical and Electrical technology Beijing 100083 China 3. Department of Engineering Mechanics Tsinghua University Beijing 100084 China

With the development of computer technology and numerical simulation technology, computer aided engineering (CAE) technology has been widely applied to many fields. One of the main obstacles, which hinder the further application of CAE technology, is how to successfully identify the parameters of the selected model. An elementary framework for parameter identification of a complex model is provided in this paper. The framework includes the construction of objective function, the design of the optimization method and the evaluation of the identified results, etc. The parameter identification process is described in this framework, taking the parameter identification of the superplastic constitutive model considering grain growth for Ti-6Al-4V at 927°C as an example. The objective function is the weighted quadratic sums of the difference between the experimental and computational data for the stress-strain relationship and the grain growth relationship; the designed optimization method is a hybrid global optimization method, which is based on the feature of the objective function and incorporates the strengths of genetic algorithm (GA), the Levenberg-Marquardt algorithm and the augmented Gauss-Newton algorithm. The reliability evaluation of parameter identification result is made through the comparison between the calculated and experimental results and between the theoretical values of the parameters and the identified ones.

关键词： constitutive model parameter identification theory inverse analysis global optimization

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SAR image despeckling based on edge detection and nonsubsampled second generation bandelets

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Journal of Systems Engineering and Electronics 2009年第3期20卷 519-526页

作者： Zhang Wenge~(1,2),Liu Fang~(1,2),Jiao Licheng~(2,3.& Gao Xinbo~(2,3. 1.school of computer science and {3.,Xidian Univ.,Xi’an 710071,P.R.china 2.Key Lab.of Intelligent Perception and Image Understanding of Ministry of Education of china,Xi’an 710071,P.R.china 3.Inst,of Intelligent Information Processing,Xidian Univ.,Xi’an 710071,P.R.china school of computer science and {3. Xidian Univ. Xi'an 710071 P. R. China Key Lab. of Intelligent Perception and Image Understanding of Ministry of Education of china Xi'an 710071 P. R. China Key Lab. of Intelligent Perception and Image Understanding of Ministry of Education of china Xi'an 710071 P. R. China Inst. of Intelligent Information Processing Xidian Univ. Xi'an 710071 P. R. China

To preserve the sharp features and details of the synthetic aperture radar （SAR） image effectively when despeckling, a despeckling algorithm with edge detection in nonsubsampled second generation bandelet transform （NSBT） domain is proposed. First, the Canny operator is utilized to detect and remove edges from the SAR image. Then the NSBT which has an optimal approximation to the edges of images and a hard thresholding rule are used to approximate the details while despeckling the edge-removed image. Finally, the removed edges are added to the reconstructed image. As the edges axe detected and protected, and the NSBT is used, the proposed algorithm reaches the state-of-the-art effect which realizes both despeckling and preserving edges and details simultaneously. Experimental results show that both the subjective visual effect and the mainly objective performance indexes of the proposed algorithm outperform that of both Bayesian wavelet shrinkage with edge detection and Bayesian least square-Gaussian scale mixture （BLS-GSM）.

关键词： computer image processing synthetic aperture radar speckle edge detection nonsubsampled second generation bandelet transform Canny operator threshold shrinkage.

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Study of Cross-Media Topic Analysis and Application

Study of Cross-Media Topic Analysis and Application

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第24届中国控制与决策会议

作者： Yipeng Zhou 1,2 , Yuehua Yang 3., Meiyu Liang 3., Junping Du 3.1. school of computer science and Information Engineering, Beijing {3. and Business university, Beijing, 100048, china2. school of Information, Renmin university of china, Beijing, 100872, china 3. Beijing Key Laboratory of Intelligent telecommunications Software and Multimedia, Beijing university of posts and telecommunications, Beijing, 100876, china

As the rapid development of SNS applications, a uniform topic analysis on different media data is very important for emergency management and decision-making. In this paper, a cross-media topic analysis framework is proposed to solve problems of cross-media data modeling, associated topic reasoning and integrated search. On this basis, a food safety emergency monitoring system is established to meet the needs of food safety emergency management in complex decision-making environment.

关键词： topic analysis cross-media food safety emergency

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