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Stability of multiquadric quasi-interpolation to approximate high order derivatives

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science china Mathematics 2010年第4期53卷 985-992页

作者： MA LiMin 1,2 & WU ZongMin 1,1 Shanghai Key Laboratory for Contemporary Applied Mathematics,School of Mathematical sciences,Fudan university,Shanghai 200433,china 2 department of Information and computer science,zhejiang Gongshang university,hangzhou 310018,china 1. Shanghai Key Laboratory for Contemporary Applied Mathematics School of Mathematical Sciences Fudan University Shanghai 200433 China2. Department of Information and Computer Science Zhejiang Gongshang University Hangzhou 310018 China

Numerical simulation of the high order derivatives based on the sampling data is an important and basic problem in numerical approximation,especially for solving the differential equations *** classical method is the divided difference ***,it has been shown strongly unstable in ***,it can only be used to simulate the lower order derivatives in *** simulate the high order derivatives,this paper suggests a new method using multiquadric *** stability of the multiquadric quasi-interpolation method is compared with the classical divided difference ***,some numerical examples are presented to confirm the theoretical *** theoretical results and numerical examples show that the multiquadric quasi-interpolation method is much stabler than the divided difference *** property shows that multiquadric quasi-interpolation method is an efficient tool to construct an approximation of high order derivatives based on scattered sampling data even with noise.

关键词： numerical differential radial basis functions (RBFs) Hardy’s multiquadric (MQ) quasiinterpolation divided difference method white noise expectation variance

Effect of Transition Metal on the Electrochemical Performances of Some Intermetallic Anodes for Lithium Ion Batteries

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Journal of Materials science & technology 2004年第3期20卷 344-346页

作者： Jian XIE Xinbing ZHAO Gaoshao CAO Mingjian ZHAO Yaodong ZHONG department of Materials science and Engineering, zhejiang university hangzhou 310027,china department of Materials science and Engineering Zhejiang University Hangzhou310027 China

Some transition metal antimonides were prepared by levitation melting and subsequent ball-milling. The electrochem-ical behaviors of these materials as new candidate negative electrode materials in lithium ion secondary batteries wereinvestigated. It was found that they exhibited significantly larger volumetric capacity than carbon-based materi-als. The formation and composition of solid electrolyte interface (SEI) film were characterized by electrochemicalimpedance spectroscopy (EIS) and Fourier transform infra-red (FTIR) spectroscopy.

关键词： Antimonide Lithium ion batteries Anode materials Levitation melting

Loop reduction techniques for reachability analysis of linear hybrid automata

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science china(Information sciences) 2012年第12期55卷 2663-2674页

作者： PAN MinXue,LI You,BU Lei & LI XuanDong State Key Laboratory for Novel Software technology,department of computer science and technology,Nanjing university,Nanjing 210093,china 1. State Key Laboratory for Novel Software technology Department of Computer Science and Technology Nanjing University Nanjing 210093 China

The problem of reachability analysis of linear hybrid automata(LHA) is very *** paper considers to improve the efficiency of the reachability analysis by optimizing the structures of *** identify two types of loops called the flexible loops and the zero loops,and present the techniques to replace the repetitions of those loops in the behavior of LHA with finite sequences of locations and in the meantime simplify the associated *** techniques work not only for the polyhedral computing based algorithms but also for the bounded model checkers.

关键词： real-time and hybrid systems linear hybrid automata reachability analysis

Retransmission or redundancy:Transmission reliability study in wireless sensor networks

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science china(Information sciences) 2012年第4期55卷 737-746页

作者： WEN Hao 1,LIN Chuang 1,REN FengYuan 1,ZHOU Jia 1,YUE Yao 2 & HUANG XiaoMeng 1 1 department of computer science and technology,Tsinghua university,Beijing 100084,china 2 department of computer science,Cornell university,Upson Hall 4161,NY,USA 1. department of computer science and technology Tsinghua University Beijing 100084 China2. Department of Computer Science Cornell University Upson Hall NY 4161 USA

As an application-driven network,wireless sensor network generally requires data reliability to maintain detection and response *** two approaches,namely,retransmission and redundancy,have been proposed to enhance data reliability,the theoretical work is required to evaluate their impact on transmission reliability and energy *** this paper,we offer a comprehensive theoretical study on packet arrival probability and average energy consumption for both *** analysis and simulations indicate that when loss probabilities remain low or moderate,erasure coding,a typical redundancy-based scheme,is more energy efficient than *** also demonstrate that the resistance capability of erasure coding against packet loss weakens as the hop number increases,which motivates us to propose two improved mechanism based on the idea of the loss detection and the loss ***,the simulation results carried out using TOSSIM verify the performance of different mechanisms both in the chain topology and the tree topology.

关键词： reliability energy efficiency retransmission redundancy erasure coding

Computing the Intersection of a Plane and Geometric Primitives in VRML Model for Rapid Prototyping Software

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武汉理工大学学报 2006年第S3期28卷 918-923页

作者： LI Zhanli SUN Xiuying department of computer science & technology,Xi’an university of science and technology,Xi’an 710054,china, department of computer science & technology Xi'an University of Science and TechnologyXi'an 710054China

VRML(Virtual Reality Modeling Language)format as an international standard for virtual reality,has al- ready been widely adopted for graphical representation of 3D objects over the *** VRML model in RP(Rapid Prototyp- ing)can reduce the precision loss which is caused by triangulation in generating STL *** exploring a slicing method and de- veloping a slicing software for VRML model is important and significant to improve the accuracy of RP *** inter- sections of a plane and VRML model is the key operation in slicing *** paper presents a method for calculating the in- tersections between a set of parallel planes and VRML geometric *** on the analysis of the relative position between a plane and a geometric primitive,intersection conditions in all cases were obtained,and the geometric parameters and corresponding equations of intersections were *** algorithm had been tested,and applications show that it is robust and effective.

关键词： slicing VRML rapid prototyping intersection cylinder cone

Effect of interfacial reactions on solid erosion of Al_(18) B_4O_(33) whisker-reinforced AC4C Al alloy matrix composites

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中国有色金属学会会刊：英文版 2000年第3期10卷 332-336页

作者： TU Jiang ping(涂江平) 1, 3 , ZHU Li ping(朱丽萍) 2, MENG Liang(孟亮) 1, LIU Mao sen(刘茂森) 1, M. Matsumura 3 1. department of Materials science and Engineering, zhejiang university, hangzhou 310027, P.R.china 2. zhejiang technology Sc zhejiang Univ Dept Mat Sci & Engn Hangzhou 310027 Peoples R China zhejiang Technol Sch Bldg Mat Hangzhou 310014 Peoples R China Hiroshima Univ Dept Chem Engn Higashihiroshima 7398527 Japan

Solid erosion of as cast and treated 19.5%(volume fraction) Al 18 B 4O 33 whisker/AC4C Al composites was investigated at room temperature under steady state conditions. The results indicated that the interfacial reaction between the whisker and matrix alloy have an effect on the erosion characteristics of the composites. The erosion resistance of the composites with a strongly bonded whisker matrix interface and the higher whisker strength resulted from suitable reaction treatment can be improved at high impact angles and is the same as the as cast composites at low angle. For the composites after excessive reaction treatment, the weak and brittle interface fractures easily at small strains, and the whiskers with relative low strength and low hardness at the specimen surface can not effectively resist the microcutting or microploughing action, thus the composites exhibit reduced erosion resistance.

关键词： interfacial reactions solid erosion metal matrix composites

A formal method to real-time protocol interoperability testing

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science in china(Series F) 2008年第11期51卷 1723-1744页

作者： WANG ZhiLiang1,3,YIN Xia2,3 & JING ChuanMing2,3 1 Network Research Center,Tsinghua university,Beijing 100084,china 2 department of computer science and technology,Tsinghua university,Beijing 100084,china 3 Tsinghua National Laboratory for Information science and technology(TNList) ,Beijing 100084,china 1. Network Research Center Tsinghua University Beijing 100084 China 3. Tsinghua National Laboratory for Information science and technology (TNList) Beijing 100084 China 2. department of computer science and technology Tsinghua University Beijing 100084 China

Interoperability testing is an important technique to ensure the quality of implementations of network communication protocol. In the next generation Internet protocol, real-time applications should be supported effectively. However, time constraints were not considered in the related studies of protocol interoperability testing, so existing interoperability testing methods are difficult to be applied in real-time protocol interoperability testing. In this paper, a formal method to real-time protocol interoperability testing is proposed. Firstly, a formal model CMpTIOA （communicating multi-port timed input output automata） is defined to specify the system under test （SUT） in real-time protocol interoperability testing; based on this model, timed interoperability relation is then defined. In order to check this relation, a test generation method is presented to generate a parameterized test behavior tree from SUT model; a mechanism of executability pre-determination is also integrated in the test generation method to alleviate state space explosion problem to some extent. The proposed theory and method are then applied in interoperability testing of IPv6 neighbor discovery protocol to show the feasibility of this method.

关键词： protocol testing interoperability testing real-time testing test generation timed input output automata(TIOA)

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高温下金属薄膜生长初期的模拟研究

物理学报 2001年第8期50卷 1555-1559页

作者：吴锋民施建青吴自勤浙江工业大学科学研究中心杭州310014 浙江工业大学应用物理系杭州310014 中国科学技术大学天文与应用物理系合肥230026

采用实际的生长模型和物理参量 ,用MonteCarlo方法对高温下金属薄膜的生长过程进行了模拟研究 .综合考虑了原子沉积、扩散、成核、生长和扩散原子的再蒸发、原子沿岛周界扩散和岛的合并等众多过程后 ,模拟得到与实验结果相当一致的薄膜... 详细信息

采用实际的生长模型和物理参量 ,用MonteCarlo方法对高温下金属薄膜的生长过程进行了模拟研究 .综合考虑了原子沉积、扩散、成核、生长和扩散原子的再蒸发、原子沿岛周界扩散和岛的合并等众多过程后 ,模拟得到与实验结果相当一致的薄膜生长形貌及其相应的定量结果 .通过动态统计薄膜生长过程中的岛数目及薄膜生长率 ,得到实验中不易直接获得的高温下薄膜生长的许多细节 ,如岛数目和薄膜生长率随表面温度。

关键词：薄膜成核岛密度薄膜生长率金属蒙特卡罗模拟

Generalized Group Signature Scheme

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Wuhan university Journal of Natural sciences 2001年第Z1期6卷 500-504页

作者： Li Zi chen 1, Wu Xu dong 2, Dai Yi qi 1 1 department of computer science and technology, Tsinghua university, Beijing 100084, china 2 department of computer science,Jiaozuo university, Jiaozuo 454003, china department of computer science and technology Tsinghua University Beijing China department of computer science Jiaozuo University Jiaozuo China

The concept of generalized group signature scheme will be present. Based on the generalized secret sharing scheme proposed by Lin and Harn, a non interactive approach is designed for realizing such generalized group signature scheme. Using the new scheme, the authorized subsets of the group in which the group member can cooperate to produce the valid signature for any message can be randomly specified.

关键词： digital signature group signature secret sharing