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science china(Information sciences) 2010年第7期53卷 1481-1486页

作者： ZHENG WeiMin1,2 1department of computer science and Technology, tsinghua university, beijing 100084, china 2tsinghua National Laboratory for Information science and Technology, beijing 100084, china department of computer science and Technology Tsinghua University Beijing China tsinghua National Laboratory for Information science and Technology Beijing China

Cloud computing has become a trend that draws attention from both academia and industry all over the world. This paper unveils details of tsinghua Cloud, a comprehensive solution for cloud computing developed by Tsing... 详细信息

关键词： cloud computing distributed file system virtual computing environment data sharing

A user-space file system for on-demand legacy desktop software

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science china(Information sciences) 2011年第6期54卷 1142-1150页

作者： ZHANG youHui 1,2 , SU GeLin 1,2 & ZHENG WeiMin 1,2 1 department of computer science and Technology, tsinghua university, beijing 100084, china 2 tsinghua National Laboratory for Information science and Technology, tsinghua university, beijing 100084, china department of computer science and Technology Tsinghua University Beijing China tsinghua National Laboratory for Information science and Technology Tsinghua University Beijing China

Some user-level virtualization technologies have been used to convert legacy software (like the existing Windows desktop applications) into the on-demand software without any modification. To give the client a friendly and compatible method to access on-demand legacy software across the Internet, this paper presents a clientend file system for this usage case. It is a Windows user-space file system based on the cloud storage (where the on-demand software is stored), which converts the local file system accesses into remote visits. Quite a few optimizations are adopted and adjusted to suit the file-access-pattern of on-demand software, including the local cache, metadata/data/software prefetch and content-addressable storage (CAS), to decrease the number of remote visits and/or to overlap IO (input/output) operations with software execution. Detailed access-pattern analyses are also presented. This file system has been implemented and tests show that it is practical for much daily-used software-a local cache of limited size can provide up to 80% hit ratio and the corresponding overhead of running-time is about 37%. Owing to this method, on any compatible and networked computer, a user can use his/her personalized software conveniently although it does not exist on the local host.

关键词： on-demand software software as a service user-space file system cloud storage

A verifiable low-level concurrent programming model based on colored Petri nets

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science china(Information sciences) 2011年第10期54卷 2013-2027页

作者： WANG ShengYuan & DONG Yuan department of computer science and Technology,tsinghua university,beijing 100084,china department of computer science and Technology Tsinghua University Beijing China

Concurrent programs written in a machine-level language are being used in many areas,but the verification of such programs brings various new challenges to the programming language *** of existing contributions on verifying the safety properties of concurrent programs are for high-level languages,specifications,or calculi in the *** to the lack of abstraction at a low level,additional work is needed to extend these methods to machine-level *** paper describes an approach to integrate Petri nets into low-level concurrent programs to form a new programming model (abstract machine).A program in the programming model is a restricted version of colored Petri net,with transitions colored by assembly codes for machine-level threads,and places colored by shared data consisting of memory locations or *** analysis and verification approaches for usual Petri nets can be applied indirectly for such a low-level concurrent program.

关键词： low-level concurrent programs colored Petri nets abstract machine verification

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 Beijing China State Key Laboratory of Intelligent Technology and Systems Beijing China tsinghua National Laboratory for Information science and Technology Beijing China

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

Aeroservoelastic model based active control for large civil aircraft

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science china(Technological sciences) 2010年第4期53卷 1126-1137页

作者： FAN Yong1,ZHU JiHong1,HU ChunHua2,MENG XianYu1,WANG XiangYang2 & GE AiXue1 1 department of computer science and Technology,tsinghua university,beijing 100084,china 2 School of Astronautics and Aeronautics,tsinghua university,beijing 100084,china department of computer science and Technology Tsinghua University Beijing China School of Astronautics and Aeronautics Tsinghua University Beijing China

A modeling and control approach for an advanced configured large civil aircraft with aeroservoelasticity via the LQG method and control allocation is *** models and implementation issues for the multi-input/multi-output(MIMO) aeroservoelastic system simulation developed for a flexible wing with multi control surfaces are described.A fuzzy logic based optimization approach is employed to solve the constrained control allocation problem via intelligently adjusting the components of output vector and find a proper vector in the attainable moment set(AMS) *** basic idea is to minimize the L2 norm of error between the desired moment and achievable moment using the designing freedom provided by redundantly allocated actuators and control *** the constraints of control surfaces,in order to obtain acceptable performance of aircraft such as stability and maneuverability,the fuzzy weights are updated by the learning algorithm,which makes the closed-loop system ***,an application example of flight control designing for the advanced civil aircraft is discussed as a *** studies we have performed showed that the advanced configured large civil aircraft has good performance with the proper designed control law designed via the proposed *** gust alleviation and flutter suppression are applied with the synergetic effects of elevator,ailerons,equivalent rudders and *** results show good closed loop performance and meet the requirement of constraint of control surfaces.

关键词： modeling active control aeroelastic flutter suppression control allocation

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(2,n)secret sharing scheme for gray and color images based on Boolean operation

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science china(Information sciences) 2012年第5期55卷 1151-1161页

作者： DONG Lin 1,WANG DaoShun 1,LI ShunDong 2 & DAI YiQi 1 1 department of computer science and Technology,tsinghua university,beijing 100084,china 2 School of computer science,Shaanxi Normal university,Xi'an 710062,china department of computer science and Technology Tsinghua University Beijing China School of computer science Shaanxi Normal University Xi’an China

Traditional secret sharing (SS) schemes can reconstruct the secret precisely,but have high com-putation *** secret sharing (VSS) schemes use human visual system to reconstruct the secret without cryptographic computation,but have pixel expansion and loss of *** et *** a (2,n)-SS scheme for binary images based on Boolean operation,which has low computation complexity,no pixel expansion and the contrast is 1/*** this paper,we first construct an r runs (2,n)-SS scheme to improve the contrast of Wang et al.'s binary (2,n)-SS *** we present two approaches to construct r runs (2,n)-SS schemes for grayscale image and color *** two approaches are both based on Boolean operation,while one approach uses halftone technology and the other uses bit level *** proposed schemes have low computation complexity and almost ideal contrast.

关键词： secret sharing scheme Boolean operation halftone contrast

Multi-dimensional Liu Process,Differential and Integral

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Multi-dimensional Liu Process,Differential and Integral

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

第一届中国智能计算大会

作者： cuilian you department of mathematical sciences,tsinghua university,beijing 100084,china department of mathematics and computer science,hebei university,baoding 071002,china

＜正＞Liu process is a type of fuzzy process and is the counter- part of Brownian motion（Wiener process）in stochastic process,Liu formula in fuzzy process is corresponding to Ito formula in stochastic process,and Liu integral in fuzzy process plays the role of Ito integral in stochastic *** this paper,Liu process,Liu formula and Liu integral were extended to the case of multi-dimensional.

关键词： fuzzy variable fuzzy process Liu process Liu integral

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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 Beijing China State Key Laboratory of Intelligent Technology and System Department of Computer Science and Technology Tsinghua University Beijing China

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

Corslet: A shared storage system keeping your data private

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science china(Information sciences) 2011年第6期54卷 1119-1128页

作者： XUE Wei 1,2 , SHU JiWu 1,2 , LIU Yang 1 & XUE Mao 1 1 department of computer science and Technology, tsinghua university, beijing 100084, china 2 tsinghua National Laboratory for Information science and Technology, tsinghua university, department of computer science and Technology Tsinghua University Beijing China tsinghua National Laboratory for Information science and Technology Tsinghua University Beijing China

With the exponential growth of digital data, it is becoming more and more popular to store data in shared distributed storage systems inside the same organization. In such shared distributed storage systems, an ordinary user usually does not have the control permission over the whole system, and thus cannot secure data storage or data sharing of his own files. To solve this issue, this paper proposes a new system architecture to secure file storing and sharing efficiently over untrusted shared storage and network environments. Based on this architecture, this paper designs and implements a stackable secure storage system called Corslet. Corslet can run directly on deployed underlying storage systems without modification, while bringing end-to-end confidentiality and integrity as well as efficient access control for user data. For individual users, Corslet is easy to use, and does not require users to maintain or manage any keys on their client machines locally. The Bonnie++ and IOzone benchmark results show that the throughput of Corslet over NFS can achieve more than 90% of native NFS throughput in most tests, proving that Corslet can provide enhanced security for user data while maintaining acceptable performance.

关键词： storage security access control key management shared file system