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Decentralized Cooperation Strategies in Two-Dimensional Traffic of Cellular Automata

Communications in Theoretical Physics 2012年第12期58卷 883-890页

作者：方峻覃征陈喜群冷彪徐朝晖江子能 Department of Computer Science and Technology Tsinghua University Key Laboratory for Information System Security Ministry of Education Department of Civil Engineering Tsinghua University School of Computer Science & Engineering Beihang University School of Software Tsinghua University

We study the two-dimensional traffic of cellular automata using computer simulation. We propose two type of decentralized cooperation strategies, which are called stepping aside (CS-SA) and choosing alternative routes (CS-CAR) respectively. We introduce them into an existing two-dimensional cellular automata (CA) model. CS-SA is designed to prohibit a kind of ping-pong jump when two objects standing together try to move in opposite directions. CS-CAR is designed to change the solution of conflict in parallel update. CS-CAR encourages the objects involved in parallel conflicts choose their alternative routes instead of waiting. We also combine the two cooperation strategies (CS-SA-CAR) to test their combined effects. It is found that the system keeps on a partial jam phase with nonzero velocity and flow until the density reaches one. The ratios of the ping-pong jump and the waiting objects involved in conflict are decreased obviously, especially at the free phase. And the average flow is improved by the three cooperation strategies. Although the average travel time is lengthened a bit by CS-CAR, it is shorten by CS-SA and CS-SA-CAR. In addition, we discuss the advantage and applicability of decentralized cooperation modeling.

关键词： two-dimensional traffic model phase transition decentralized cooperation strategy cellular automata

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Outsourcing large matrix inversion computation to a public Cloud

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IEEE Transactions on Cloud Computing 2013年第1期1卷 78-87页

作者： Lei, Xinyu Liao, Xiaofeng Huang, Tingwen Li, Huaqing Hu, Chunqiang State Key Laboratory of Power Transmission Equipment and System Security and New Technology College of Computer Science Chongqing University Chongqing400044 China Texas A and M University at Qatar PO Box 23874 Doha Qatar Department of Computer Science George Washington University WashingtonDC20052 United States

Cloud computing enables resource-constrained clients to economically outsource their huge computation workloads to a cloud server with massive computational power. This promising computing paradigm inevitably brings in new security concerns and challenges, such as input/output privacy and result verifiability. Since matrix inversion computation (MIC) is a quite common scientific and engineering computational task, we are motivated to design a protocol to enable secure, robust cheating resistant, and efficient outsourcing of MIC to a malicious cloud in this paper. The main idea to protect the privacy is employing some transformations on the original matrix to get an encrypted matrix which is sent to the cloud, and then transforming the result returned from the cloud to get the correct inversion of the original matrix. Next, a randomized Monte Carlo verification algorithm with one-sided error is employed to successfully handle result verification. In this paper, the superiority of this novel technique in designing inexpensive result verification algorithm for secure outsourcing is well demonstrated. We analytically show that the proposed protocol simultaneously fulfills the goals of correctness, security, robust cheating resistance, and high efficiency. Extensive theoretical analysis and experimental evaluation also show its high efficiency and immediate practicability. © 2013 IEEE.

关键词： Outsourcing

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A Game Theoretic Method to Model and Evaluate Attack-Defense Strategy in Cloud Computing

A Game Theoretic Method to Model and Evaluate Attack-Defense...

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IEEE International Conference on Services Computing (SCC)

作者： Guisheng Fan Huiqun Yu Liqiong Chen Dongmei Liu State Key Laboratory for Novel Software Technology Nanjing University China Department of Computer Science and Engineering East China University of Science and Technology Shanghai China Department of Computer Science and Information Engineering Shanghai Institute of Technology Shanghai China

Cloud computing has attracted much interest recently from both industry and academic. However, it is difficult to construct perfectly secure mechanisms, in face of complex and various attack behaviors in cloud computing. In this paper, a stochastic game model (SGM) is proposed to describe the attack-defense behavior in cloud computing, the physical machine, attack-defense behavior and their attributes are modeled by using SGM, thus forming the attack-defense game model of cloud computing. On this basis, the Nash equilibrium of attack-defense process of physical machine is computed in order to get the best defense strategy. The related theories of Petri net are used to verify the correctness of proposed method. The computation formula and the actual meaning of performance index are given. The enforcement algorithm is also proposed. Both case study and simulation results show that the proposed method can adapt quickly to the changes in cloud application, thus improving the security of cloud computing.

关键词： Computational modeling Cloud computing Games Analytical models Stochastic processes security Nash equilibrium

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An in-depth measurement and analysis of popular private tracker systems in China

An in-depth measurement and analysis of popular private trac...

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IEEE International Conference on Communications (ICC)

作者： Qiang Li Tao Qin Xiaohong Guan Qinghua Zheng Qiuzhen Huang Department of Automation Tsinghua National Laboratory for Information Science and Technology Beijing China Ministry of Education Key Laboratory for Intelligent Networks and Network Security Xi'an Jiaotong University Xi'an China

In recent years, a novel BitTorrent (BT) technology, Private Tracker (PT), has received extensive attentions in academia. Due to its huge amount of traffic volumes and population, it is essential to understand the characteristics for system management. In this paper, by using the data crawled from a number of well-known PT sites in China, we present an in-depth measurement and analysis on the PT system, in terms of resources characteristics and user behavior characteristics. Our analysis on the activity and age distribution of torrents reveals that the sequence of torrent activities follows a power-law distribution and the sequence of torrent ages follows a linear distribution. By investigating the characteristics of the core users and the resources in different PT sites, two observations have been made. Firstly, every PT site has a number of users with stable levels who contribute to the survivability and popularity of the site. Secondly, a large amount of redundancy exists among the distributed resources and many popular resources are duplicated among these sites, which leads to the quick spread of pirate resources. Based on the measurement results, we analyze the drawbacks of PT mechanisms and propose useful suggestions to promote the healthy development and performance of PT.

关键词： Redundancy Communities Educational institutions Peer-to-peer computing Time measurement Videos Motion pictures

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Mining User Interests in Web Logs of an Online News Service Based on Memory Model

Mining User Interests in Web Logs of an Online News Service ...

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International Conference on Networking, Architecture, and Storage (NAS)

作者： Wei Wang Dongyan Zhao Haining Luo Xin Wang Key Laboratory on Information Security Engineering University of CAPF Xi'an China Institute of Computer Science & Technology Peking University Beijing China Computer Management Center of the Armed Police General Hospital Beijing China

User profiling plays an important role in online news recommendation systems. In this paper, we analyze the relationship between users' clicking behaviors and the category of the news story to model user's interests by mining web log data of an adaptive news system. We train a Memory-based User Profile (MUP), which imitates human being's learning, remembering and forgetting mechanisms, to predict users' potential interests dynamically. We mainly focus on experimental analysis to refine the MUP scheme. Firstly, we materialize the meanings of all parameters of MUP by important factors (i.e., absorbing factor, forgetting factor, timescale and learning strength) in human being's learning and forgetting process. Secondly, we demonstrate how to determine the values of parameters for different users to reflect their distinct learning and forgetting abilities. Thirdly, we derive a threshold from MUP's recursion formula, which can be used to simply distinguish long-term and short-term interests. Our evaluations are carried out on IdoIcan's web log data, results show MUP can model user's profile effectively.

关键词： Computational modeling Adaptation models Entertainment industry Business computers Blogs Conferences

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Quantum hacking of a continuous-variable quantum-key-distribution system using a wavelength attack

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Physical Review A 2013年第6期87卷 062329-062329页

作者： Jing-Zheng Huang Christian Weedbrook Zhen-Qiang Yin Shuang Wang Hong-Wei Li Wei Chen Guang-Can Guo Zheng-Fu Han Key Laboratory of Quantum Information University of Science and Technology of China Hefei 230026 China Center for Quantum Information and Quantum Control Department of Electrical and Computer Engineering and Department of Physics University of Toronto Toronto Ontario M5S 3G4 Canada

The security proofs of continuous-variable quantum key distribution are based on the assumptions that the eavesdropper can neither act on the local oscillator nor control Bob's beam splitter. These assumptions may be invalid in practice due to potential imperfections in the implementations of such protocols. In this paper, we consider the problem of transmitting the local oscillator in a public channel and propose a wavelength attack which allows the eavesdropper to control the intensity transmission of Bob's beam splitter by switching the wavelength of the input light. Specifically we target continuous-variable quantum key distribution systems that use the heterodyne detection protocol using either direct or reverse reconciliation. Our attack is proved to be feasible and renders all of the final keys shared between the legitimate parties insecure, even if they have monitored the intensity of the local oscillator. To prevent our attack on commercial systems, a simple wavelength filter should be randomly added before performing monitoring detection.

关键词： Quantum cryptography

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Network survivability evaluation model based on immune evolution and multiple criteria decision making

Network survivability evaluation model based on immune evolu...

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4th International Conference on Cyber-Enabled Distributed Computing and Knowledge Discovery, CyberC 2012

作者： Wang, Chunlei Fang, Lan Dai, Yiqi Ming, Liang Miao, Qing Wang, Dongxia Department of Computer Science and Technology Tsinghua University Beijing China Nation Key Laboratory of Science and Technology on Information System Security Beijing China

ISBN: (纸本)9780769548104

Network survivability has the characteristics of complexity, dynamic evolution and uncertainty, which has become one of the most important indicators of evaluating network performance. Network survivability evaluation is a process of confirming the degree to which the network survivability technology and mechanism can defend network threats. Firstly, it needs to extract useful information from the actual system and establish the model, then the model is analyzed and necessary information is extracted. Finally, the survivability characteristics of the network can be measured and evaluated based on the model and extracted information. Current network security research lacks of models and methods which guide network survivability evaluation effectively. In this paper, we firstly describe the elements of network survivability evaluation model and their relationships, then propose a network survivability evaluation model based on evolutionary computation which includes the immune evolutionary algorithm for network survivability metric weight solving and network survivability evaluation method based on multiple criteria decision making. Finally, the correctness and effectiveness of the proposed model is validated through experimental analysis. © 2012 IEEE.

关键词： Network security

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TAR~*:an improved process similarity measure based on unfolding of Petri nets

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计算机集成制造系统 2012年第8期18卷 1774-1784页

作者： WANG Wen-xing WANG Jian-min School of Software Tsinghua University Beijing 100084 China Ministry of Education Key Laboratory for Information System Security Tsinghua UniversityBeijing 100084 China Tsinghua National Laboratory for Information Science and Technology Beijing 100084 China

Determining the similarity degree between process models was very important for their management,reuse,and *** approaches either focused on process model's structural aspect,or had inefficiency or imprecision in behavioral *** at these problems,a novel similarity measure which extended an existing method named Transition Adjacent Relation(TAR) with improved precision and efficiency named TAR * was *** ability of measuring similarity was extended by eliminating the duplicate tasks without impacting the *** precision,TARs was classified into repeatable and unrepeatable ones to identify whether a TAR was involved in a *** new kinds of TARs were added,one related to the invisible tasks after the source place and before sink place,and the other representing implicit *** efficiency,all TARs based on unfolding instead of its reach ability graph of a labeled Petri net were calculated to avoid state space *** on artificial and real-world process models showed the effectiveness and efficiency of the proposed method.

关键词： transition adjacent relation unfolding Petri nets behavioral similarity

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Suppress of Substrate-assisted Depletion Effects in Super Junction LDMOS on Thin Film SOI

Suppress of Substrate-assisted Depletion Effects in Super Ju...

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The 2nd International Conference on Materials science and Manufacturing（ICMSM2013）

作者： Chao Xia Xinhong Cheng Zhongjian Wang Dawei He Duo Cao Tingting Jia Yuehui Yu Dashen Shen National State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Micro-system & Information TechnologyChinese Academy of Sciences Electrical Department of Electrical and Computer Engineering University of Alabama in Huntsville

Conventional super-junction lateral double diffused MOSFET （SJ-LDMOS） fabricated on Silicon on Insulator （SOI） substrate suffers from low breakdown voltage under the same on-resistance due to substrate-assisted depletion effect. To suppress this effect, it is important to find the charge density in the inversion layer under buried oxide. In this paper, we propose a charge density equation and its formulation. The results were used in a 3D device simulator to optimize the device structure. The experimental results confirm that the equation is useful to optimize device performance. The breakdown voltage of structure increased 54% and on-state-resistance decreased 58% compared to conventional SJ device. The device fabrication procedure is fully compatible with mainstream SOI CMOS process.

关键词： super-junction LDMOS SOI substrate-assisted depletion effect

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A Generic Construction of Proxy Signatures from Certificateless Signatures

A Generic Construction of Proxy Signatures from Certificatel...

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International Conference on Advanced information Networking and Applications (AINA)

作者： Lei Zhang Qianhong Wu Bo Qin Josep Domingo-Ferrer Peng Zeng Jianwei Liu Ruiying Du Shanghai Key Laboratory of Trustworthy Computing Software Engineering Institute East China Normal University Shanghai China UNESCO Chair in Data Privacy Department of Computer Engineering and Mathematics Universitat Rovira i Virgili Tarragona Spain Key Laboratory of Aerospace Information Security and Trusted Computing Ministry of Education School of Computer Wuhan University China Department of Maths School of Science Xi'an University of Technology China School of Electronic and Information Engineering Beijing University of Aeronautics and Astronautics China

The primitive of proxy signatures allows the original signer to delegate proxy signers to sign on messages on behalf of the original signer. It has found numerous applications in distributed computing scenarios where delegation of signing rights is common. Certificate less public key cryptography eliminates the complicated certificates in traditional public key cryptosystems without suffering from the key escrow problem in identity-based public key cryptography. In this paper, we reveal the relationship between the two important primitives of proxy signatures and certificate less signatures and present a generic conversion from the latter to the former. Following the generic transformation, we propose an efficient proxy signature scheme with a recent certificate less signature scheme.

关键词： Artificial intelligence Bismuth Games Public key cryptography Educational institutions

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