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Generalized gradient projection neural networks for nonsmooth optimization problems

science china(information sciences) 2010年第5期53卷 990-1005页

作者： LI GuoCheng 1 , SONG ShiJi 2 ? & WU Cheng 2 1 department of Mathematics, beijing information {3. and technology university, beijing 100192, china 2 department of automation, tsinghua university, beijing 100084, china department of Mathematics Beijing Information Science and Technology University Beijing China department of automation Tsinghua University Beijing China

Generalized gradient projection neural network models are proposed to solve nonsmooth convex and nonconvex nonlinear programming problems over a closed convex subset of R n . By using Clarke’s generalized gradient, the neural network modeled by a differential inclusion is developed, and its dynamical behavior and optimization capabilities both for convex and nonconvex problems are rigorously analyzed in the framework of nonsmooth analysis and the differential inclusion theory. First for nonconvex optimization problems, the quasi convergence results similar to those achieved by previous work are proved. For convex optimization problems, the global convergence results are proved, i.e. any trajectory of the neural network converges to an asymptotically stable equilibrium point, which is an optimal solution of the primal problem whenever it exists. This result remains valid even if the initial condition is chosen outside the feasible set. In addition, an asymptotic control result involving a Tykhonov like regularization shows that any trajectory of the revised neural network can be forced to converge toward a particular optimal solution of the primal problem. Finally, two simulation optimization algorithms for solving the optimization and control problems are designed respectively, and three typical simulation experiments are illustrated to present the accuracy and efficiency of theoretical convergence results of this paper.

关键词： nonsmooth optimization problem generalized gradient projection networks differential inclu sions convergence

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A TTCN-3.based protocol testing system and its extension

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science in china(Series F) 2008年第11期51卷 1703-1722页

作者： YIN Xia1,3.WANG ZhiLiang2,3.JING ChuanMing1,3.& SHI XinGang2,3.1 department of Computer science and technology,{3. university,beijing 100084,china 2 Network Research Center,{3. university,beijing 100084,china 3.{3. national Laboratory for {13. science and technology(TNList) ,beijing 100084,china department of Computer science and technology Tsinghua University Beijing China tsinghua national Laboratory for information {3. and technology (TNList) Beijing China Network Research Center Tsinghua University Beijing China

The protocol testing technology used in the next generation Internet should satisfy some new challenges and requirements. This paper focuses on the test suite description and test implementation techniques. TTCN-3.is chosen as the test suite description language and extended in both syntax and semantics to satisfy the requirements of protocol robustness testing. PITSv3. a protocol integrated testing system based on TTCN-3. is developed, and the extensions for robustness testing are implemented. Finally, two practical test applications are presented.

关键词： protocol testing TTCN-3 PITSv3 robustness testing

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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,{3., beijing 100084, china 2State Key Laboratory of Intelligent technology and Systems, beijing 100084, china 3.9} 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 {3. 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

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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 International 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, {3. 100084, china 2. Center of Quantum information science and technology, tsinghua national Laboratory for information science and technology, {3. 100084, china 3. Institute of Physics, School of sciences, {3. university of Posts and Telecommunications, {3. 100876, china) Key Laboratory for Atomic and Molecular Nanosciences Department of Physics Tsinghua University Beijing 100084 China Center of Quantum information science 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.

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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,{3., beijing 100084, china 2 tsinghua national Laboratory for information science and technology,{3., department of Computer science and technology Tsinghua University Beijing China tsinghua national Laboratory for information {3. 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

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Arbitrarily long distance quantum communication using inspection and power insertion

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Chinese science Bulletin 2009年第1期54卷 158-162页

作者： WANG WanYing1,2,WANG Chuan1,2,ZHANG GuangYu1,3.& LONG GuiLu1,2 1 department of Physics,tsinghua university,{3. 100084,china 2 tsinghua national Laboratory for information science and technology,tsinghua university,{3. 100084,china 3.College of Applied science,Harbin university of science and technology,Harbin 150080,china department of Physics Tsinghua University Beijing China tsinghua national Laboratory for information {3. and technology Tsinghua University Beijing China College of Applied science Harbin University of Science and Technology Beijing China

The biggest obstacle for long distance quantum communication is the channel loss and the channel noise on photons. In this paper,a method to solve this problem was analyzed using inspection and power insertion (IPI). It is proved that quantum communication may be established over arbitrarily long distance using this technology. The amount of resources required is a polynomial function of the dis-tance. IPI is proposed as a general technique to prolong quantum secure direct communication where secret messages are transmitted directly over a quantum channel.

关键词：长距离量子通信量子安全通信量子密匙分布噪声

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Optimal MAC based cooperative spectrum sensing in cognitive radio networks

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science china(information sciences) 2012年第6期55卷 1388-1396页

作者： CHEN Zhong 1,ZHANG XianDa 1 & YANG LanJuan 2 1 State Key Laboratory of Intelligent technology and Systems,tsinghua national Laboratory for {3. science and technology,department of automation,tsinghua university,beijing 100084,china 2 Institute of Command automation,PLA university of science and technology,Nanjing 210007,china State Key Laboratory of Intelligent technology and Systems Tsinghua National Laboratory for Information Science and Technology Department of Automation Tsinghua University Beijing China Institute of Command automation PLA University of Science and Technology Nanjing China

This paper considers a cognitive radio (CR) system in non-ideal fading wireless channels and pro-poses cooperative spectrum sensing schemes based on coherent multiple access channels (MAC),serving as an alternative way to improve the cooperative spectrum sensing performance and provide space diversity for spec-trum *** statistics are transmitted using a common channel from the secondary users (SUs) to a fusion center (FC) where the global decision is *** optimal scaling factors of the proposed schemes are obtained by maximizing the detection probability under a target false alarm probability and a transmit power *** the proposed optimal MAC scheme has high computational complexity,a sub-optimal solu-tion based on maximization of the deflection coefficient (DC) is also *** results show that the proposed algorithms can significantly improve the spectrum sensing performance and approach the detection baseline.

关键词： cognitive radio (CR) spectrum sensing multiple access channel (MAC) deflection coefficient optimization

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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 university, Anhui 23.03.,{3. 2State Key Laboratory of Intelligent technology and Systems, beijing 100084,{3. 3.7} national Laboratory of information science & technology, beijing 100084,{3. 4information science & technology College, Computer science & technology department, tsinghua university, beijing 100084,{3. Computer science & technology College Anhui University Anhui China State Key Laboratory of Intelligent technology and Systems Beijing China tsinghua national Laboratory of information {3. & technology Beijing China information science & technology College Computer Science & Technology Department Tsinghua University Beijing 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

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The structural analysis of fuzzy measures

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science china(information sciences) 2011年第1期54卷 38-50页

作者： ZHANG Ling1,ZHANG Bo2 & ZHANG YanPing1 1 Computer science College,Anhui university,Hefei 23.03.,china 2State Key Lab of Intelligent {3. & Systems tsinghua national Lab for information science & {3. information science & {3. College,Computer science & {3.,tsinghua university,beijing 100084,china Computer science College Anhui University Hefei China State Key Lab of Intelligent technology & Systems tsinghua national Lab for information {3. & technology information science & technology College Computer Science & Technology Tsinghua University Beijing China

From quotient space based granular computing theory we explore the fuzzy measures of fuzzy sets. Based on the structural analysis of fuzzy sets,we present an"isotropism"*** this assumption we achieved the following insights:(1)the uniqueness of a fuzzy measure being isotropic on a finite complete semi-ordered set;(2)the necessary and suffcient condition of the isomorphism for fuzzy measure functions in fuzzy mathematics;(3.the necessary and suffcient condition that fuzzy measures have fuzzy and granular monotonicity;(4)under a certain assumption,the analytic expression for fuzzy *** results clarify the relationship between fuzzy measures and granular computing,reveal the essence of fuzzy measures,and provide a simple way of constructing fuzzy measures.

关键词： quotient space fuzzy set fuzzy measure rough set structural analysis

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Absence of State Collapse and Revival in a Superconducting Charge Qubit

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Communications in Theoretical Physics 2007年第12期48卷 1029-1032页

作者： HUO Wen-Yi~1 and LONG Gui-Lu~(1,2,3.~1 department of Physics amd Key Laboratory for Quantum information and Measurements,tsinghua {3.,beijing100084,china~2 Key Laboratory for Atomic and Molecular Nanosciences,tsinghua {3.,beijing 100084,china~3.national Laboratory for information science and technology,Hsinghua {3.,beijing 100084,china department of Physics amd Key Laboratory for Quantum information and Measurements Tsinghua University Beijing 100084 China Key Laboratory for Atomic and Molecular Nanosciences Tsinghua University Beijing 100084 China national Laboratory for information science and {3. Hsinghua University Beijing 100084 China

The Hamiltonian of a superconducting charge qubit with a configuration of dc SQUID contains an interac-tion between the LC oscillator part and charge *** interaction may leads to quantum state collapse and revivalwhich degrades the charge qubits and leads to serious *** analysis shows that the existing charge qubitparameters do not lead to this phenomenon,which is very good for the superconducting charge

关键词： quantum computer superconducting charge qubit absence and revival

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