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Level Set interface treatment and its application in Euler method

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science china(Physics,Mechanics & Astronomy) 2010年第2期53卷 227-236页

作者： WU KaiTeng1,2,HAO Li3.WANG Cheng4 & ZHANG Li1,2 1 Numerical Simulation Sichuan Higher School Key Laboratory,Neijiang normal university,Neijiang 641112,china 2 {3. of Mathematics and information science,Neijiang normal university,Neijiang 641112,china 3.{3. of science,beijing university of Civil Engineering and Architecture,beijing 100044,china 4 State Key Laboratory of Explosion science and technology,beijing Institute of technology,beijing 100081,china 1. Numerical Simulation Sichuan Higher School Key Laboratory Neijiang Normal University Neijiang 641112 China2. College of Mathematics and Information Science Neijiang Normal University Neijiang 641112 China3. College of Science Beijing University of Civil Engineering and Architecture Beijing 100044 China4. State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing 100081 China

Level Set interface treatment method is introduced into Euler method,which is employed for interface treatment method for multi-materials. Combined with the ghost fluid method,the moving interface is tracked. Fifth-order WENO spatial discretization and third-order TVD Runge-Kutta time discretization methods are used. Shock-wave action on bubble,implosion and velocity field Shock effect bubbles; implosion and velocity field are simulated by means of LS-MMIC3. programmed by C++. Nu-merical results show that the Level Set interface treatment method is effective and feasible for multi-material interface treatment in comparison with the WENO method.

关键词： Euler method Level Set method shock-wave action on bubble implosion numerical simulation

Scenario simulation and forecast of land use/cover in northern china

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Chinese science Bulletin 2008年第9期53卷 1401-1412页

作者： LI YueChen 1,2,3.& HE ChunYang 3.1 college of Geographical science, Chongqing normal {3., Chongqing 400047, china 2 college of Resources and Environmental science, Chongqing {3., Chongqing 400044, china 3.college of Resources science & technology, beijing normal university, {13. 100875, china college of Geographical science Chongqing Normal University Chongqing 400047 China college of Resources and Environmental science Chongqing University Chongqing 400044 China college of Resources science & technology Beijing Normal University Beijing 100875 China

Modeling land use/cover scenario changes and its potential impacts on structure and functions of ecosystem in typical regions are helpful to understanding the interactive mechanism between land use/cover system and ecosystem. Based on the analysis of the existing land use/cover simulation and forecast models, a land use/cover scenario dynamics model by the integration of System Dynamics (SD) model, Back Propagation Neural Network (BPNN) and Cellular Automata (CA) model is developed with land use/cover scenario changes in northern china in the next 3. years and simulated in this paper. The model is to simulate the land use/cover scenario demands by using a SD model at first, and then allocating the land use scenario patterns at the local scale with the considerations of land use/cover suitability, inheritance ability and neighborhood effect by using BPNN-CA model to satisfy the balance between land use/cover scenario demands and supplies. It integrates the advantages of SD, BPNN and CA. Macro-driving factors and the micro-spatial pattern are also fully taken into account. The BPNN simplifies the identification of the factors’ weights used in CA model and improves the reliability of the simulation results. The simulation accuracy of the model developed in this paper was found to be about 74%. It suggests that the model has the ability to reflect the complexity of land use/cover system at different scales to some extent and it is a useful tool for assessing the potential impacts of land use system on ecosystem. The simulated results also indicate that the urban land, water area and forest will increase significantly, and farmland and unable land will decrease gradually. Obvious land use/cover changes will take place in the farming-pastoral zone and the southeast area of northern china.

关键词：土地利用中国北方细胞自动机系统动力学

Fuzzy tolerance quotient spaces and fuzzy subsets

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science china(information sciences) 2010年第4期53卷 704-714页

作者： ZHANG Ling1 & ZHANG Bo2,3.4* 1Computer science & technology college, Anhui {3., Anhui 23.03., china 2State Key Laboratory of Intelligent technology and Systems, beijing 100084, china 3.singhua National Laboratory of information science & technology, beijing 100084, china 4information science & technology college, Computer science & technology Department, Tsinghua {3., beijing 100084, china 1. Computer science & technology college Anhui University Anhui 230039 China2. State Key Laboratory of Intelligent Technology and Systems Beijing 100084 China3. Tsinghua National Laboratory of Information Science & Technology Beijing 100084 China4. Information Science & Technology College Computer Science & Technology Department Tsinghua University Beijing 100084 China

The structure and characteristic of fuzzy subsets are discussed by using the concepts of granulation and hierarchy in quotient space theory. First, the equivalence relation based quotient space theory is extended to the fuzzy tolerance relation. Second, the isomorphism and its discriminant of fuzzy tolerance relations are discussed. Finally, by using the fuzzy tolerance relation to define the fuzzy subset, its properties are addressed. The main results are given below: (1) several equivalent statements of fuzzy tolerance relations; (2) the definition of isomorphism of fuzzy tolerance relations; (3. the isomorphic discriminant of fuzzy tolerance relations; (4) the definition and properties of fuzzy subsets based on the fuzzy tolerance relations; and (5) the necessary and sufficient condition of the isomorphism of fuzzy subsets. These results will help us further comprehend the concepts of fuzzy tolerance relations and fuzzy subsets.

关键词： Fuzzy tolerance relation quotient space isomorphism fuzzy subset

Multiparty simultaneous quantum identity authentication with secret sharing

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science china(Physics,Mechanics & Astronomy) 2008年第3期51卷 321-327页

作者： YANG YuGuang1,2,WEN QiaoYan3.& ZHANG Xing4,5 1 college of Computer science and technology,{3. university of technology,{3. 100022,china 2 State Key Laboratory of information Security (Graduate university of the Chinese Academy of sciences),{3. 100049,china 3.School of science,{3. university of Posts and Telecommunications,{3. 100876,china 4 Institute of Electronic technology,information Engineering university,Zhengzhou 450004,china 5 Trusted Computing Laboratory,{3. university of technology,{3. 100022,china college of Computer science technology Beijing University of Technology Beijing 100022 China State Key Laboratory of information Security [Graduate university of the Chinese Academy of sciences] Beijing 100049 China School of science Beijing University of Posts Telecommunications Beijing 100876 China Institute of Electronic technology Information Engineering University Zhengzhou 450004 China Trusted Computing Laboratory Beijing University of Technology Beijing 100022 China

Two multiparty simultaneous quantum identity authentication (MSQIA) protocols based on secret sharing are presented. All the users can be authenticated by a trusted third party (TTP) simultaneously. In the first protocol,the TTP shares a random key K with all the users using quantum secret sharing. The ith share acts as the authentication key of the ith user. When it is necessary to perform MSQIA,the TTP generates a random number R secretly and sends a sequence of single photons encoded with K and R to all the users. According to his share,each user performs the corresponding unitary operations on the single photon sequence sequentially. At last,the TTP can judge whether the impersonator exists. The sec-ond protocol is a modified version with a circular structure. The two protocols can be efficiently used for MSQIA in a network. They are feasible with current technol-ogy.

关键词： quantum identity authentication secret sharing quantum cryptography

Entropy number and non-linear approximations on multivariate Besov space by manifolds of finite pseudo-dimension

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Progress in Natural science:Materials International 2006年第3期16卷 260-265页

作者： LONG Jingfan and FANG Gensun (School of Mathematical sciences, beijing normal university, beijing 100875,{3. Department of Computer science, information technology Institute, beijing 100101,{3.) [a]School of Mathematical sciences Beijing Normal University Beijing China [b]Department of Computer science Information Technology Institute Beijing China

We determine the asymptotic order of entropy number and optimal non -linear approximations of anisotropic periodic Besov class of Bpθr(Td') (1≤p≤∞,1≤0≤∞) by manifolds of finite pseudo-dimension in the metric Lq... 详细信息

关键词： Pseudo-dimension anisotropic Besov class of functions entropy number nonlinear width.

Quantum threshold group signature

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science china(Physics,Mechanics & Astronomy) 2008年第10期51卷 1505-1514页

作者： YANG YuGuang1,2,3.& WEN QiaoYan4 1 college of Computer science and technology, {3. university of technology, {3. 100124, china 2 State Key Laboratory of Integrated Services Network, Xidian university, Xi’an 710071, china 3.State Key Laboratory of information Security (Graduate university of Chinese Academy of sciences), {3. 100049, china 4 State Key Laboratory of Networking and Switching technology, {3. university of Posts and Tele-communications, {3. 100876, china college of Computer science and technology Beijing University of Technology Beijing 100124 China State Key Laboratory of Integrated Services Network Xidian University Xi’an 710071 China State Key Laboratory of information Security Graduate University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Networking and Switching technology Beijing University of Posts and Telecommunications Beijing 100876 China

In most situations, the signer is generally a single person. However, when the message is written on behalf of an organization, a valid message may require the approval or consent of several persons. Threshold signature is a solution to this problem. Generally speaking, as an authority which can be trusted by all members does not exist, a threshold signature scheme without a trusted party appears more attractive. Following some ideas of the classical Shamir’s threshold signature scheme, a quantum threshold group signature one is proposed. In the proposed scheme, only t or more of n persons in the group can generate the group signature and any t-1 or fewer ones cannot do that. In the verification phase, any t or more of n signature receivers can verify the message and any t-1 or fewer receivers cannot verify the validity of the signature.

关键词： threshold quantum signature trusted party quantum cryptography

Threshold proxy quantum signature scheme with threshold shared verification

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science china(Physics,Mechanics & Astronomy) 2008年第8期51卷 1079-1088页

作者： YANG YuGuang1,3.4 & WEN QiaoYan2 1 college of Computer science and technology,{3. university of technology,{3. 100124,china 2 State Key Laboratory of Networking and Switching technology,{3. university of Posts and Tele-communications,{3. 100876,china 3.State Key Laboratory of Integrated Services Network,Xidian university,Xi’an 710071,china 4 State Key Laboratory of information Security(Graduate university of Chinese Academy of sciences) ,{3. 100049,china 1. college of Computer science and technology Beijing University of Technology Beijing 100124 China 3. State Key Laboratory of Integrated Services Network Xidian University Xi’an 710071 China 4. State Key Laboratory of information Security (Graduate university of Chinese Academy of sciences) Beijing 100049 China 2. State Key Laboratory of Networking and Switching technology Beijing University of Posts and Telecommunications Beijing 100876 China

A threshold proxy quantum signature scheme with threshold shared verification is proposed. An original signer could authorize a group as its proxy signers. Then only t or more of n persons in the proxy group can generate the proxy signature on behalf of the original signer and any t-1 or fewer ones cannot do that. When the proxy signature needs to be verified,any t or more of n persons belonging to the verification group can verify the message and any t-1 or fewer ones cannot verify the validity of the proxy signature.

关键词： quantum signature threshold proxy quantum group signature threshold shared verification

Threshold quantum secret sharing between multi-party and multi-party

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science china(Physics,Mechanics & Astronomy) 2008年第9期51卷 1308-1315页

作者： YANG YuGuang1,2,3.& WEN QiaoYan4 1 college of Computer science and technology,{3. university of technology,{3. 100124,china 2 State Key Laboratory of Integrated Services Network,Xidian university,Xi’an 710071,china 3.State Key Laboratory of information Security (Graduate university of Chinese Academy of sciences),{3. 100049,china 4 State Key Laboratory of Networking and Switching technology,{3. university of Posts and Tele-communications,{3. 100876,china college of Computer science and technology Beijing University of Technology Beijing 100124 China State Key Laboratory of Integrated Services Network Xidian University Xi’an 710071 China State Key Laboratory of information Security (Graduate university of Chinese Academy of sciences) Beijing 100049 China State Key Laboratory of Networking and Switching technology Beijing University of Posts and Telecommunications Beijing 100876 China

A threshold quantum secret sharing (TQSS) scheme between multi-party and multi-party was proposed using a sequence of single photons,which is useful and efficient when the parties of communication are not all present. We described the process of this TQSS scheme and discussed its security. It was shown that entan-glement is not necessary for quantum secret sharing. Moreover,the theoretic effi-ciency was improved to approach 100% as almost all the instances can be used for generating the private key,and each photon can carry one bit of information. This protocol is feasible with the present-day technique.

关键词： threshold quantum secret sharing quantum cryptography single photon multi-party and multi-party

Threshold quantum secure direct communication without entanglement

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science china(Physics,Mechanics & Astronomy) 2008年第2期51卷 176-183页

作者： YANG YuGuang1,3.& WEN QiaoYan2 1 college of Computer science and technology, {3. university of technology, {3. 100022, china 2 School of science, {3. university of Posts and Telecommunications, {3. 100876, china 3.State Key Laboratory of {13. Security (Graduate School of Chinese Academy of sciences), {3. 100049, china 1. college of Computer science and technology Beijing University of Technology Beijing 100022 China 3. State Key Laboratory of information Security (Graduate School of Chinese Academy of sciences) Beijing 100049 China 2. School of science Beijing University of Posts and Telecommunications Beijing 100876 China

For the first time, a threshold quantum secure direct communication (TQSDC) scheme is presented. Similar to the classical Shamir's secret sharing scheme, the sender makes n shares, S1, …, Sn of secret key K and each receiver keeps a share secretly. If the sender wants to send a secret message M to the receivers, he en-codes the information of K and M on a single photon sequence and sends it to one of the receivers. According to the secret shares, the t receivers sequentially per-form the corresponding unitary operations on the single photon sequence and ob-tain the secret message M. The shared shares may be reusable if it can be judged that there is no eavesdropper in line. We discuss that our protocol is feasible with current technology.

关键词： quantum secure direct communication threshold secure direct communication quantum secret sharing