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

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science{1.(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 {1., Tsinghua University, beijing 1.0084, china 2 Tsinghua national laboratory for information science and {1., Tsinghua University, beijing 1.0084, china 1. Department of Computer science and {1. Tsinghua University Beijing 100084 China2. Tsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing 100084 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

Density functional theory study of the reaction paths of reactions of CH3C（O）O2 radicals with HO2 in the gas phase

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Progress in Natural science:Materials Inter{1. 2006年第12期16卷 1269-1274页

作者： ZHOU Yuzhi~ 1.2 , ZHANG Shaowen~1.and LI Qianshu~1.*(1. State Key laboratory of Explosion {1. and technology, beijing Institute of technology, beijing 1.0081. china 2. beijing Institute of Education, beijing 1.0044, china) [a]State Key laboratory of Explosion {1. and technology Beijing Institute of Technology Beijing China [b]beijing Institute of Education Beijing China

A DFT study on the reactions between CH_3C（O）O_2and HO_2radicals has been carried out. It is suggested that both the triplet and singlet potential surfaces involve a complex mechanism with the formation of loosely bound intermediate complexes of reactants and products. The reaction prefers to occur on the triplet surface to produce peracetic acid (CH_3C（O）O_2H) and triplet O_2molecule. The CH_3C（O）O_2H can further convert into CH_3C（O）O and HO radicals.

关键词： acetyl peroxy radicals HO2 radicals reaction mechanism DFT.

Experimental study on fire smoke movement in a multi-floor and multi-room building

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science{1.(Technological sciences) 2005年第3期48卷 292-304页

作者： ZHONG Maohua 1. 2 , LI Peide 2 , LIU Tiemin 1., WEI Xing 1. 2 & LIAO Guangxuan 2 1. national Center of Safety {1. and technology, State Administration of Work Safety, beijing 1.0029, china 2. State Key laboratory of Fire {1., University of {1. and technology of china, Hefei 230026, china 1. national Center of Safety {1. and technology State Administration of Work Safety 100029 Beijing China 2. State Key laboratory of Fire {1. University of Science and Technology of China 230026 Hefei China

Fire smoke movement of multi-floor and multi-room (MFMR) fire was studied at the model test building in State Key laboratory of Fire {1. (SKLFS). The ingredient, temperature, air pressure difference and air velocity of smoke were measured and analyzed. Meanwhile, the hazard of smoke ingredient to exposed occupants was analyzed based on the national standard, Occupational Exposure Limit for Hazardous Agents in the Workplace (GBZ2-2002). The experimental results showed that the maximum temperature difference in MFMR fire was located along the vertical height from the fire source. With the spreading and diffusion of smoke, the temperature of smoke layer would tend to be no difference. In the fire of woodpile and kerosene, the main smoke ingredients such as SO 2 , CO and CO 2 would first exceed human’s average physiological limit, while smoke ingredients such as NO and NO 2 would come behind. Because of the higher fluctuation range and frequency of air pressure difference of smoke in multi-layer building fire, the fire smoke would spread around everywhere of the passageway and made the human evacuation more difficult.

关键词： multi-floor and multi-room,fire experiment,smoke spread,smoke toxicity.

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Influence of magnetic current on the ground state entanglement in an isotropic transverse XY chain

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Progress in Natural science:Materials Inter{1. 2007年第10期17卷 1147-1151页

作者： Liu Dan1,2 , Zhang Yong3 and Long Guilu1,2(1. Key laboratory for Atomic and Molecular Nanosciences, and Department of Physics, Tsinghua University, beijing 1.0084, china 2. Center of Quantum information science and technology, Tsinghua national laboratory for information science and technology, beijing 1.0084, china 3. Institute of Physics, School of sciences, beijing University of Posts and Telecommunications, beijing 100876, china) Key laboratory for Atomic and Molecular Nano{1.s and Department of Physics Tsinghua University Beijing 100084 China Center of Quantum information {1. and technology Tsinghua National Laboratory for information Science and Technology Beijing 100084 China Institute of Physics School of Sciences Beijing University of Posts and Telecommunications Beijing 100876 China

We study the ground state entanglement in a three-qubit XY chain under the influence of a magnetization current. It is found that the ground state changes from a W state to a disentangled state as the magnetic field varies. When the Lagrange multiplier λ>3, namely under a strong magnetic current, the ground state holds onto a W state for a large range of the magnetic field strength. A phase transition to the magnetization-current phase occurs under a certain condition.

关键词： Heisenberg-XY chain magnetic-current phase transition.

Fusion tracking in color and infrared images using joint sparse representation

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science{1.(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 1.0084, china 2State Key laboratory of Intelligent technology and Systems, beijing 1.0084, china 3Tsinghua national laboratory for information science and technology, beijing 1.0084, china 1. Department of Computer science and {1. Tsinghua University Beijing 100084 China2. State Key Laboratory of Intelligent Technology and Systems Beijing 100084 China3. Tsinghua National Laboratory for Information Science and Technology Beijing 100084 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

Corslet: A shared storage system keeping your data private

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science{1.(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 {1., Tsinghua University, beijing 1.0084, china 2 Tsinghua national laboratory for information science and {1., Tsinghua University, 1. Department of Computer science and {1. Tsinghua University Beijing 100084 China2. Tsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing 100084 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

RST transforms resistant image watermarking based on centroid and sector-shaped partition

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science{1.(information sciences) 2012年第3期55卷 650-662页

作者： ZHAO Yao1.2*, NI RongRong1.2* & ZHU ZhenFeng1.2* 1.nstitute of information {1., beijing Jiaotong University, beijing 1.0044, china 2beijing Key laboratory of Advanced information {1. and Network technology, beijing 1.0044, china 1. Institute of information {1. Beijing Jiaotong University Beijing 100044 China2. Beijing Key Laboratory of Advanced Information Science and Network Technology Beijing 100044 China

A novel digital watermarking scheme featuring centroid-based sectoring is proposed in this paper. To get higher robustness against geometric attacks, such as rotation, scaling, and translation (RST), a delicate synchronization mechanism was developed and incorporated into the proposed approach. During the process of watermark embedding, the original image was partitioned into sectors based on the image centroid. Synchronization information as well as the message bits is then embedded into these sectors. With the help of the centroid-based sectoring and synchronization information, the proposed approach is capable of restoring the correct sectoring even if it has experienced severe geometric distortion. This attribute ensures the correct recovery of embedded watermarks and contributes to the robustness of the proposed scheme. A series of experiments have been conducted to verify the feasibility and effectiveness of the proposed approach. Experimental results show that the proposed scheme possesses good robustness against RST attacks and considerable robustness against other common image processing attacks.

关键词： digital watermarking geometrical transform attacks RST transforms

Self-healing routing: failure,modeling and analysis

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science{1.(information sciences) 2011年第3期54卷 609-622页

作者： XU MingWei 1.2 , LI Qi 1.2 , YANG Yuan 1.2 , HOU MeiJia 1.2 & PAN LingTao 1.2 1.Department of Computer science, Tsinghua University,{1., china 2 Tsinghua national laboratory for information science and technology (TNList),{1., china 1. Department of Computer science Tsinghua University Beijing 100084 China2. Tsinghua National Laboratory for Information Science and Technology (TNList) Beijing 100084 China

Network failures occur frequently, and self-healing ability of existing routing protocols cannot guarantee fast route convergence under these failures without impacting packet forwarding. During routing convergence, network routes may be incorrect and even routing black holes and loops occur, which will result in extensive packet loss and thus influence network performance. To solve this problem, several improved routing solutions have been proposed. In this paper, we propose the concept and model of self-healing routing and analyze the key problems in current intra-domain and inter-domain self-healing routing protocols after briefly reviewing the characteristics of network failures. We classify the different self-healing solutions into two categories based on their design principles: routing restoration and routing protection, and systematically analyze these different typical solutions. Finally, we discuss several key issues in self-healing routing and propose a hybrid protection and restoration based routing scheme.

关键词： failure intra-domain routing inter-domain routing self-healing routing

Fuzzy tolerance quotient spaces and fuzzy subsets

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science{1.(information sciences) 2010年第4期53卷 704-714页

作者： ZHANG Ling1.& ZHANG Bo2,3,4* 1.omputer science & {1. College, Anhui University, Anhui 230039, china 2State Key laboratory of Intelligent {1. and Systems, beijing 1.0084, china 3Tsinghua national laboratory of information science & {1., beijing 1.0084, china 4information science & {1. College, Computer science & {1. Department, Tsinghua University, beijing 1.0084, china 1. Computer science & {1. 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