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IEEE Annual Joint Conference: INFOCOM, IEEE computer and Communications Societies

作者： D. Guo J. Wu H. Chen X. Luo Key Laboratory of CISR Technology College of Information Systems and Management National University of Defense Technology Changsha Hunan China Department of Computer Science and Engineering Florida Atlantic University Boca Raton FL USA

The topological properties of peer-to-peer overlay networks are critical factors that dominate the performance of these systems. Several non-constant and constant degree interconnection networks have been used as topologies of many peer-to-peer networks. One of these has many desirable properties: the Kautz digraph. Unlike interconnection networks, peer-to-peer networks need a topology with an arbitrary size and degree, but the complete Kautz digraph does not possess these properties. In this paper, we propose Moore: the first effective and practical peer-to-peer network based on the incomplete Kautz digraph with O (log d N ) diameter and constant degree under a dynamic environment. The diameter and average routing path length are [log d ( N ) - log d (1 + 1/ d )] and log d N , respectively, and are shorter than that of CAN, butterfly, and cube-connected-cycle. They are close to that of complete de Bruijn and Kautz digraphs. The message cost of node joining and departing operations are at most 2.5 d log d N and (2.5 d + 1) log d N , and only d and 2 d nodes need to update their routing tables. Moore can achieve optimal diameter, high performance, good connectivity and low congestion evaluated by formal proofs and simulations.

关键词： Peer to peer computing Network topology Routing Multiprocessor interconnection networks Costs Hypercubes Communications Society Laboratories Educational institutions Management information systems

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Quadratic Trigonometric Spline Curves with Multiple Shape Parameters

Quadratic Trigonometric Spline Curves with Multiple Shape Pa...

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10th IEEE International Conference on computer Aided Design and computer Graphics(第十届CAO/Graphics国际会议)

作者： Xiaoqin Wu Xuli Han Shanmin Luo School of Mathematical Science & Computing Technology Central South UniversityChangsha 410083P.R.C School of Mathematical Science & Computing Technology Central South UniversityChangsha 410083P.R.C School of Mechanical Engineering Hunan University of Science & TechnologyXiangtan 411201P.R.China

Quadratic trigonometric spline curves with multiple shape parameters are presented in this *** to the cubic B-spline curves, each trigonometric spline curve segment is generated by four consecutive control points. The trigonometric spline curves with a non -uniform knot vector are C1 continuous. With a uniform knot vector, the trigonometric spline curves are C3 continuous when all shape parameter λ1 =I. Taking different values of the shape parameters,one can globally or locally adjust the shapes of the curves,so that the trigonometric spline curves can be close to the cubic B-spline curves or closer to the given control polygon than the cubic B-spline curves. The trigonometric spline curves also can represent ellipse and generate a family of ellipse with the same control points. A quadratic trigonometric B閦ier curves are also introduced as a special case of the given trigonometric spline curves.

关键词： Spline Polynomials Shape control computers Mathematics Mechanical engineering Solid modeling Bismuth

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New Boost matrix converter and its control strategy

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Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South university (science and technology) 2007年第3期38卷 517-522页

作者： Zhang, Xiao-Ping Tang, Hua-Ping Zhu, Jian-Lin Yue, Zhou Liu, Sha-Sha School of Mechanical and Electrical Engineering Central South University Changsha 410083 China College of Information and Electrical Engineering Hunan University of Science and Technology Xiangtan 411201 China College of Information Engineering Xiangtan University Xiangtan 411105 China

Based on the low voltage transfer ratio of conventional matrix converter, a new matrix converter referred to as a Boost matrix converter was proposed. The basic configuration of this new topology and its fundamental were introduced, the analytic expression concerning functions relation of voltage transfer ratio to duty cycle was deduced, the two effective control strategies, i.e., sliding mode control and double-loop control, were expounded particularly and their different attributes were compared. The validity and feasibility of the new topology were tested by simulation. The results show that the modulation of voltage transfer ratio and output frequency can be achieved optionally through this new converter by means of the two control strategies and an ideal sine output wave with less distortion can be gotten, so the inherent problem of conventional matrix converter with low voltage transfer ratio is solved effectively.

关键词： Electric converters

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A Stern-based Collusion-Secure Software Watermarking Algorithm and Its Implementation

A Stern-based Collusion-Secure Software Watermarking Algorit...

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International Conference on Multimedia and Ubiquitous engineering (MUE)

作者： Jieqing Ai Xingming Sun Yunhao Liu Ingemar J. Cox Guang Sun Yi Luo School of Computer and Communication Hunan University Changsha China UCL Adastral Park Campus University College London UK Hong Kong University of Science and Technology Hong Kong China Hunan College of Financial and Economics Changsha China

Stem algorithm is a robust static software watermarking scheme. It can resist many common attacks except collusive attacks. In this paper we propose an improved Stern algorithm, make it has the ability of resisting collusive attacks and simplify its implementation at the same time. Furthermore, we describe the implementation of our algorithm and the issues that arise when targeting MSIL. We then validated it by experiments against a variety of attacks.

关键词： Watermarking Software algorithms Books Frequency Robustness Resists Application software computer aided instruction Educational institutions Protection

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Microstructure and properties of a titanium alloy by metal injection molding

Beijing Keji Daxue Xuebao/Journal of University of Science a...

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Beijing Keji Daxue Xuebao/Journal of university of science and technology Beijing 2007年第7期29卷 721-724页

作者： Guo, Shibo Zhang, Houan Zhang, Rongfa He, Xinbo Qin, Mingli Qu, Xuanhui College of Electromechanical Engineering Hunan University of Science and Engineering Xiangtan 411201 China Jiangxi Key Laboratory of Surface Engineering Jiangxi Science and Technology Normal University Nanchang 330013 China Materials Science and Engineering School University of Science and Technology of Beijing Beijing 100083 China

Titanium alloy parts were prepared by metal injection molding, binder was removed from the parts by solvent debinding process, and the brown parts were densified in vacuum atmosphere. The as-sintered specimens were treated through hot-isostatic pressure at 960°C and 140 MPa, and titanium alloy compacts were annealed at 720-760°C for 1-1.5 h. SEM observations showed that the titanium alloy had a uniform dial microstructure with many equiaxed α grains and a little β grains. XRD results indicated that Ti3Al phase was found in the alloy when the annealing temperature was higher than 800°C.

关键词： Annealing

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RUNTIME SOFTWARE ARCHITECTURE MODEL BASED ON DESIGN HIERARCHY

RUNTIME SOFTWARE ARCHITECTURE MODEL BASED ON DESIGN HIERARCH...

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2007 International Conference on Machine Learning and Cybernetics(IEEE第六届机器学习与控制论国际会议)

作者： CHANG-SHENG LIU CHANG-YUN LI JING-TIAN TANG YING CHENG School of Info-physics and Geomatics Engineering Central South University Hunan ChangSha 410083Ch Department of Computer Science & Technology Zhuzhou Institute of Technology Zhuzhou 412008 China School of Info-physics and Geomatics Engineering Central South University Hunan ChangSha 410083Ch ChangSha Aeronautical Vocational and Technical College Hunan ChangSha 410014China

On line system is hard to evolve dynamically because its runtime SA (Software Architecture) exists implicitly.A model of runtime SA based on design space is put forward, in the model runtime SA is expressed explicitly as first-class *** concept separation between abstract SA (ASA)on meta-layer and physical SA (PSA)on base-layer provides methods to take on SA views at diverse levels of abstraction and manage SA for users, thereby supports the reuse of software framework and component when system is running, and enhances system flexibility and *** we have given an ADL (dynamic architecture description) of runtime software architecture model based on design ***, we discuss dynamic structure reconfiguration issues.

关键词： Software architecture Design hierarchy ADL Dynamic reconfiguration

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A Role-Based Semantic Authorization Framework for Workflow Management Systems

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电子学报(英文版) 2006年第1期15卷 55-59页

作者： LIU Jianxun CHEN Haiyan TANG Mingdong Hunan Knowledge Grid Laboratory Hunan University of Science and Technology Xiangtan 411201 China School of Computer Science and Engineering Hunan University of Science and Technology Xiangtan 411201 China

Authorization is an essential part in Workflow management systems (WfMS) and the role-based authorization model is commonly adopted in most commercial and research workflow systems. However, role-based model alone is not sufficient to meet the authorization requirements when not considering the organization hierarchy. In this paper, we present a role-based semantic authorization framework for WfMS, which combines organizational levels and roles together to construct a 2-tuple atomic authorization term. To implement this framework, an authorization model is introduced. A set of atomic authorization predicates are presented. Based on these predicates, formal authorization expression can be composed to express the assignment of authorization terms to workflow activities.

关键词：工作流管理系统授权管理需求分析活度

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Microstructure and physical properties of Sn-20Bi-X lead-free solders

Hunan Daxue Xuebao/Journal of Hunan University Natural Scien...

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hunan Daxue Xuebao/Journal of hunan university Natural sciences 2007年第3期34卷 49-52页

作者： Yang, Shi-Qiang Lei, Xiao-Juan Li, Yuan-Shan Chen, Zhen-Hua College of Materials Science and Engineering Hunan Univ. Changsha 410082 China School of Computer Science National Defense Univ. of Science and Technology Changsha 410073 China

Sn-20Bi lead-free solders were studied in alloying method. Adding alloy element Ag, In, Ga or Sb into Sn-20Bi, the influences of the change of Ag, In, Ga or Sb contents on their microstructure and physical properties were investigated. The results showed that, when the content of Ag was 0.7%, Ga was 0.5%, or In was 0.1%, the melting points of the solder reduced correspondingly and the segregation of Bi decreased, and the microstructure and physical properties were better. Sb was not suitably added solely, and the microstructure of Sn-Bi-Sb solder was a little worse than that of Sb-free alloys, but the hardness increased.

关键词： Soldering alloys

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Study on statistical analysis attacks and countermeasures in anonymity systems

Hunan Daxue Xuebao/Journal of Hunan University Natural Scien...

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hunan Daxue Xuebao/Journal of hunan university Natural sciences 2007年第7期34卷 73-77页

作者： Xu, Hong-Yun Jiang, Li Peng, Shu-Guang Zhang, Tao College of Computer and Communications Hunan Univ. Changsha 410082 China College of Computer Science and Engineering South China Univ. of Technology Guangzhou 510640 China

This paper focused on the effects of the fixed-rerouting path scheme and the variable-rerouting path scheme upon the anonymity degree in anonymity system based on rerouting. The probability method was adopted to prove that senders sending packets by either fixed-rerouting path or variable-rerouting path were vulnerable to certain attacks, thus degrading the anonymity degree of the sender. The dynamic fixed-rerouting path scheme was presented to resist the attacks efficiently, which were aimed at both the fixed-rerouting path scheme and the variable-rerouting path scheme, thus improving the anonymity degree of the sender. Theoretical analyses have shown that anonymity system adopting the dynamic fixed-rerouting path scheme provides a higher anonymity degree than anonymity system adopting either the fixed-rerouting path scheme or the variable-rerouting path scheme.

关键词： Data privacy

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Novel admission control algorithm for wireless/mobile networks

Hunan Daxue Xuebao/Journal of Hunan University Natural Scien...

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hunan Daxue Xuebao/Journal of hunan university Natural sciences 2007年第3期34卷 71-74页

作者： Duan, Zheng-Hua Wu, Ren-Yong Zhu, Guang-Xi College of Computer and Communication Hunan Univ. Changsha 410082 China Dept. of Electronics and Information Engineering Huazhong Univ. of Science and Technology Wuhan 430074 China

A measurement-based call admission control (CAC) algorithm was presented. The scheme measures the state parameters of cellular system, i.e., the number of handoff-dropping calls and the handoff-dropping probability at each interval, and forecasts the possible number of handoff dropping calls at next interval. Based on the forecasting value and the current handoff-dropping probability, the reservation threshold is updated. Also, a Hopfield neural network (HNN) is used to allocate bandwidth resources adaptively and fairly among the calls. The simulation results show that our CAC algorithm can guarantee the predefined handoff-dropping probability while increasing the statistical multiplexing gain in providing acceptable service grades for every connection.

关键词： Wireless networks

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