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SUPERCONVERGENCES OF THE ADINI'S ELEMENT FORSECOND ORDER EQUATION

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Journal of Computational Mathematics 1999年第6期17卷 569-574页

作者： Ping Luo(department of computer science and technology, Qinghua university, beijing 100084,china)Qun Lin(Institute of Systems science, Academia Sinica, beijing, 100080, china) 清华大学计算机系北京 100084 中科院系统科学所北京 100080

n this papers the asymptotic error expansions of Adini's element for the secondorder imhomogeneous Neumann problem are given and the superconvergence estimations are obtained. Moreover, a numerical example to support ... 详细信息

关键词： Adini's element Superconvergence estimation Asymptotic expansion.

TEXTURE DETERMINATION OF THIN FILM ZrO_2 BY ELECTRON DIFFRACTION

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Acta Metallurgica Sinica(English Letters) 1993年第12期6卷 472-473页

作者： WANG Yinghua tsinghua university,beijing,china department of Materials science and Engineering,tsinghua university,beijing 100084,china tsinghua Univ Beijing China

A method for semi-quantitative determination of thin film texture using electron diffrac- tion is *** texture state of a zirconia thin film with a cubic structure has been determined in this way and is presented as an... 详细信息

关键词： texture thin film electron diffraction ZrO_2

Optimizing write operation on replica in data grid

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science china(Information sciences) 2011年第1期54卷 1-11页

作者： XU PengZhi,WU YongWei,HUANG XiaoMeng, YANG GuangWen & ZHENG WeiMin department of computer science and technology,tsinghua university,beijing 100084,china department of computer science and technology Tsinghua University

Replication technique can improve access performance and data availability of data grid systems. So far,most related work on data replication in data grid systems focuses on read-only *** write operations have been widely used in practice,its optimization problem has not been suciently *** this paper,we show that write requests from users can be processed by a nearest site,regardless of the location of latest written *** policy of write nearby instead of write to the latest replica can improve the performance of write operations,while inconsistency is caused between multiple ***,we propose two metadata management algorithms to make sure that users can retrieve up-to-date datasets at any *** extend OptorSim to support the implementation and evaluation of our *** results of simulation show that our scheme achieves performance gains up to 3.3 compared with WriteMaster scheme.

关键词： replication data grid simulation access latency

Fuzzy tracking control design for hypersonic vehicles via T-S model

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science china(Information sciences) 2011年第3期54卷 521-528页

作者： GAO DaoXiang 1 & SUN ZengQi 2 1 School of technology, beijing Forestry university, beijing 100083, china 2 State Key Laboratory of Intelligent technology and System, department of computer science and technology, tsinghua university, beijing 100084, china School of technology Beijing Forestry University State Key Laboratory of Intelligent technology and System Department of Computer Science and Technology Tsinghua University

The main focus of this paper is on designing a T-S fuzzy controller for the hypersonic vehicle. The longitudinal dynamics of the vehicle are studied using time-scale decomposition to reduce the complexity of T-S modeling. The dynamic inversion with PI control technique is applied for the slow dynamics to derive the flight path angle command and throttle setting by taking the pilot altitude and velocity command as its inputs. The T-S fuzzy controller is designed for the fast dynamics to derive the elevator deflection to track the flight path angle command. The discrepancy between the T-S model and real vehicle model is considered by using sliding mode control for the system stability. Simulation results are included to show the effectiveness of the controller.

关键词： fuzzy control T-S model sliding mode control hypersonic vehicle

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 Network Research Center Tsinghua University department of computer science and technology Tsinghua University tsinghua National Laboratory for Information science and technology (TNList)

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)

Multi secret image color visual cryptography schemes for general access structures

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Progress in Natural science:Materials International 2006年第4期16卷 431-436页

作者： YI Feng, WANG Daoshun , LUO Ping, HUANG Liansheng and DAI Yiqi department of computer science and technology, tsinghua university, beijing 100084, china department of computer science and technology Tsinghua University Beijing 100084 China

In the proposed visual cryptography schemes for general access structures, the single secret image black-and-white visual cryptography schemes with meaningful shares have been constructed, in which the shares are innocent looking images. The meaningful shares have not been realized in single secret image color schemes; neither have the multi secret images color schemes. In this paper, the multi secret images color visual cryptography schemes for general access structures with meaningful shares are constructed by the method of matrix concatenation, the pixel expansion is obtained, and the validity of the scheme is proven. In our scheme, the different combination of meaningful color shares can be used to recover distinct color secret images. The multi secret images black-and-white visual cryptography scheme is a special case of our color scheme.

关键词： visual cryptography secret sharing scheme general access structure.

A MESSAGE-DRIVING FORMALISM FOR MODELING AND SIMULATION OF MULTI-AGENT SUPPLY CHAIN SYSTEMS

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Journal of Systems science and Systems Engineering 2011年第4期20卷 385-399页

作者： Wenzhe TAN1 Yueting CHAI2 Yi LIU3 1department of Automation, tsinghua university, beijing, 100084, china 2department of Automation, tsinghua university, beijing, 100084, china 3department of Automation, tsinghua university, beijing, 100084, china department of Automation Tsinghua University Beijing China

To acquire a competitive advantage in the expanding market, manufacturing enterprises should be able to manage their supply chains as effectively as possible. It is now becoming popular to model supply chains as multi-agent systems and use discrete event simulation to learn more about their behaviors or investigate the implications of alternative configurations. In order to enhance the computational efficiency and keep the simulation credibility, this paper proposes a message-driving formalism for the simulation of multi-agent supply chain systems. Through the message-driving formalism, the problem of shared variables is addressed and the parallel operation of agents is implemented. Simulation experiments with a prototype implementation show that the message-driving formalism is able to provide credible results in significantly less simulation time.

关键词： Supply chain multi-agent system modeling and simulation parallel discrete event simulation message-driving formalism

Fusion tracking in color and infrared images using joint sparse representation

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science china(Information sciences) 2012年第3期55卷 590-599页

作者： LIU HuaPing1,2,3 & SUN FuChun1,2,3 1department of computer science and technology, tsinghua university, beijing 100084, china 2State Key Laboratory of Intelligent technology and Systems, beijing 100084, china 3tsinghua National Laboratory for Information science and technology, beijing 100084, china department of computer science and technology Tsinghua University State Key Laboratory of Intelligent technology and Systems tsinghua National Laboratory for Information science and technology

Currently sparse signal reconstruction gains considerable interest and is applied in many fields. In this paper, a similarity induced by joint sparse representation is designed to construct the likelihood function of particle filter tracker so that the color visual spectrum and thermal spectrum images can be fused for object tracking. The proposed fusion scheme performs joint sparse representation calculation on both modalities and the resultant tracking results are fused using min operation on the sparse representation coefficients. In addition, a co-learning approach is proposed to update the reference templates of both modality and enhance the tracking robustness. The proposed fusion scheme outperforms state-of-the-art approaches, and its effectiveness is verified using OTCBVS database.

关键词： joint sparse representation fusion tracking color image infrared image

Theoretical research progress in new-generation Internet architecture

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science in china(Series F) 2008年第11期51卷 1634-1660页

作者： WU JianPing1,2,3,LIU Ying2,3 & WU Qian2,3 1 department of computer science,tsinghua university,beijing 100084,china 2 Network Research Center,tsinghua university,beijing 100084,china 3 tsinghua National Laboratory for Information science and technology(TNList) ,beijing 100084,china department of computer science Tsinghua University Network Research Center Tsinghua University tsinghua National Laboratory for Information science and technology (TNList)

Internet has become the most important information infrastructure supporting modern socio-economic development, social progress and technological Innovation. Invented 30 years ago, today Internet is facing increasingly severe technical challenges. This paper introduces the progress of the major international newgeneration Internet research plans; analyzes its basic characteristics and the principal contradictions during the development; detsiledly introduces the research carried out by 973 Project ＂Research of Future Internet Architecture＂ on the key scientific issues of new-generation Internet architecture and its latest research results; and looks to the future of the research-focus faced with the new situations of the basic research of new-generation Internet architecture as well as the new demands of innovative applications on Internet architecture.

关键词： new-generation Internet network architecture multi-dimension scalability