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Quorum systems for intrusion-tolerance based on trusted timely computing base

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Journal of Systems Engineering and Electronics 2010年第1期21卷 168-174页

作者： hua Zhou Xiangru Meng Li Zhang Xiangdong qiao The Telecommunication Engineering Institute Air Force Engineering University Xi'an 710077 E R. China

Quorum systems have been used to solve the problem of data consistency in distributed fault-tolerance systems. But when intrusions occur, traditional quorum systems have some disadvantages. For example, synchronous quorum systems are subject to DOS attacks, while asynchronous quorum systems need a larger system size （at least 3f＋1 for generic data, and f fewer for self-verifying data）. In order to solve the problems above, an intrusion-tolerance quorum system （ITQS） of hybrid time model based on trust timely computing base is presented （TTCB）. The TTCB is a trust secure real-time component inside the server with a well defined interface and separated from the operation system. It is in the synchronous communication environment while the application layer in the server deals with read-write requests and executes update-copy protocols asynchronously. The architectural hybridization of synchrony and asynchrony can achieve the data consistency and availability correctly. We also build two kinds of ITQSes based on TTCB, i.e., the symmetrical and the asymmetrical TTCB quorum systems. In the performance evaluations, we show that TTCB quorum systems are of smaller size, lower load and higher availability.

关键词： network security intrusion-tolerance quorum system trusted timely computing base (TTCB) consistency availability.

Quantum information-holding single-photon router based on spontaneous emission

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Science China(Physics,Mechanics & Astronomy) 2017年第9期60卷 1-6页

作者： GuoAn Yan HaoXue qiao hua Lu AiXi Chen School of Physics and Technology Wuhan University State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics Wuhan Institute of Physics and MathematicsChinese Academy of Sciences School of Science Hubei University of Technology Key Laboratory of Quantum Information Chinese Academy of SciencesUniversity of Science and Technology of China Department of Applied Physics Zhejiang Sci-Tech University Institute for Quantum Computing University of Waterloo

In this paper, we propose a single-photon router via the use of a four-level atom system coupled with two one-dimensional coupled-resonator waveguides. A single photon can be directed from one quantum channel into another by atomic spontaneous emission. The coherent resonance and the photonic bound states lead to the perfect reflection appearing in the incident *** fidelity of the atom is related to the magnitude of the coupling strength and can reach unit when the coupling strength matches g_a = g_b. This shows that the transfer of a single photon into another quantum channel has no influence on the fidelity at special points.

关键词： quantum router quantum information quantum network couple-resonator waveguides

Clinical outcomes of COVID-19 in elderly male patients

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Journal of Geriatric Cardiology 2020年第5期17卷 243-245页

作者： zhong-hua SUN Department of Medical Radiation Sciences Curtin UniversityPerth6845Western AustraliaAustralia

Coronavirus disease 2019(COVID-19),caused by severe acute respiratory syndrome coronavirus 2(SARS-Co V-2)has spread throughout the world involving more than 200 countries with more than 3 million confirmed cases and over 200,000 deaths worldwide.[1]COVID-19 patients primarily present with respiratory symptoms showing abnormal lung changes on chest X-ray or computed tomography(CT)with typical imaging appearances of ground glass opacities and consolidation.

关键词： Clinical features COVID-19 Male patients

Transient stochastic response of quasi integerable Hamiltonian systems

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Acta Mechanica Sinica 2013年第4期29卷 602-611页

作者： zhong-hua Liu Jian-hua Geng Wei-Qiu Zhu Department of Civil Engineering Xiamen University Department of Mechanics State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

The approximate transient response of quasi in- tegrable Hamiltonian systems under Gaussian white noise excitations is investigated. First, the averaged It6 equa- tions for independent motion integrals and the associated Fokker-Planck-Kolmogorov （FPK） equation governing the transient probability density of independent motion integrals of the system are derived by applying the stochastic averag- ing method for quasi integrable Hamiltonian systems. Then, approximate solution of the transient probability density of independent motion integrals is obtained by applying the Galerkin method to solve the FPK equation. The approxi- mate transient solution is expressed as a series in terms of properly selected base functions with time-dependent coeffi- cients. The transient probability densities of displacements and velocities can be derived from that of independent mo- tion integrals. Three examples are given to illustrate the ap- plication of the proposed procedure. It is shown that the re- suits for the three examples obtained by using the proposed procedure agree well with those from Monte Carlo simula- tion of the original systems.

关键词： Transient response ~ Stochastic averagingmethod ~ Galerkin method ~ Quasi integrable Hamiltoniansystem

Humanoid Design of Mechanical Fingers Using a Motion Coupling and Shape-adaptive Linkage Mechanism

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Journal of Bionic Engineering 2018年第1期15卷 94-105页

作者： Yi Zhang hua Deng Guoliang zhong College of Mechanical & Electrical Engineering Changsha University Changsha 410022 China State Key Laboratory of High-Performance Complex Manufacturing Central South University Changsha 410083 China School of Mechanical and Electrical Engineering Central South University Changsha 410083 China

This paper proposes a novel underactuated finger mechanism based on a motion coupling and shape-adaptive linkage design that combines anthropomorphic free motion and adaptive grasping. The proposed three-joint finger mechanism with one active Degree of Freedom （DOF） consists of a five-linkage meehanism in the proximal phalanx and a mechanism comprising two parallel planar four-bar linkages in the middle phalanx. The respective mechanism allows the simultaneously rotation of their corresponding pha- langes in the plane before making contact with an object, and can fully envelop an object, even if certain phalanges are blocked. The duel parallel four-bar linkage mechanism is adopted to improve the grasping capacity of the distal phalanx. An optimal design of the finger is presented according to anthropomorphic phalanx trajectories and maximized grasping forces obtained with consideration for the angular velocity relationships of the three phalanges and their force transmission performances. The functionality of the proposed finger mechanism is verified through multiple simulations and grasping experiments using a prototype finger.

关键词： humanoid finger underactuated mechanism linkage mechanism adaptive grasp

MODIFIED BERNOULLI ITERATION METHODS FOR QUADRATIC MATRIX EQUATION

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Journal of Computational Mathematics 2007年第5期25卷 498-511页

作者： zhong-Zhi Bai Yong-hua Gao LSEC ICMSEC Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing 100080 China

We construct a modified Bernoulli iteration method for solving the quadratic matrix equation AX^2 ＋ BX ＋ C = 0, where A, B and C are square matrices. This method is motivated from the Gauss-Seidel iteration for solving linear systems and the ShermanMorrison-Woodbury formula for updating matrices. Under suitable conditions, we prove the local linear convergence of the new method. An algorithm is presented to find the solution of the quadratic matrix equation and some numerical results are given to show the feasibility and the effectiveness of the algorithm. In addition, we also describe and analyze the block version of the modified Bernoulli iteration method.

关键词： Quadratic matrix equation Quadratic eigenvalue problem Solvent Bernoulli's iteration Newton's method Local convergence.

Nanoparticle nucleation and coagulation in a mixing layer

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Acta Mechanica Sinica 2010年第4期26卷 521-529页

作者： Jian-zhong Lin Yan-hua Liu China Jiliang University 310018 Hangzhou China Department of Mechanics Zhejiang University310027 Hangzhou China

Numerical simulation of nanoparticle nucleation and coagulation in a mixing layer with sulfuric acid vapor binary system is performed using the large eddy simulation and the direct quadrature method of moment. The distributions of number concentration, volume concentration, and average diameter of nanoparticles are obtained. The results show that the coherent structures have an important effect on the distributions of number concentration, volume concentration and average diameter of nanoparticles via continuously transporting and diffusing the nanoparticles to the area of low particle concentration. In the streamwise direction, the number concentration of nanoparticles decreases, while the volume concentration and the average diameter increase. The distributions of number concentration, volume concentration and average diameter of nanoparticles are spatially inhomogeneous. The characteristic time of nucleation is shorter than that of coagulation. The nucleation takes place more easily in the area of low temperature because where the number concentration of nanoparticles is high, while the intensity of coagulation is mainly affected by the number concentration. Both nucleation and coagulation result in the variation of average diameter of nanoparticles.

关键词： Nanoparticles Nucleation - Coagulation Mixing layer Direct quadrature method of moment

An algorithm for identifying symmetric variables based on the order eigenvalue matrix

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Frontiers of Information Technology & Electronic Engineering 2017年第10期18卷 1644-1653页

作者： Xiao-hua LI Ji-zhong SHEN Campus Information Center Zhejiang University Hangzhou 310027 China College of lnformation Science & Electronic Engineering Zhejiang University Hangzhou 310027 China

To simplify the process for identifying 12 types of symmetric variables in Boolean functions, we propose a new symmetry detection algorithm based on minterm expansion or the truth table. First, the order eigenvalue matrix based on a truth table is defined according to the symmetry definition of a logic variable. By analyzing the constraint conditions of the order eigenvalue matrix for 12 types of symmetric variables, an algorithm is proposed for identifying symmetric variables of the Boolean function. This algorithm can be applied to identify the symmetric variables of Boolean functions with or without don't-care terms. The proposed method avoids the restriction by the number of logic variables of the graphical method, spectral coefficient methods, and AND-XOR expansion coefficient methods, and solves the problem of completeness in the fast computation method. The algorithm has been implemented in C language and tested on MCNC91 benchmarks. The application results show that, compared with the traditional methods, the new algorithm is an optimal detection method in terms of the applicability of the number of logic variables, the Boolean function including don't-care terms, detection type, and complexity of the identification process.

关键词： Boolean function Symmetric variable Boolean logic algebra system Order eigenvalue matrix Truth table

On the Drinfeld-Sokolov hierarchy of type E_(6)^((1))and its topological solution

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Science China Mathematics 2021年第6期64卷 1245-1262页

作者： Weiqiang He hua-zhong Ke Chao-zhong Wu School of Mathematics Sun Yat-sen UniversityGuangzhou 510275China

In this paper we report some explicit evolutionary PDEs of the Drinfeld-Sokolov hierarchy of type E_(6)^((1)),and show how the unknown functions in these PDEs are related to the tau ***,for this hierarchy we compute its topological solution of formal series up to a certain degree,whose coefficients of monomials give the Fan-Jarvis-Ruan-Witten invariants for the E_(6) simple *** on such results we also derive several explicit evolutionary PDEs and some low-degree terms of the topological solution for the Drinfeld-Sokolov hierarchy of type F_(4)^((1)).

关键词： Drinfeld-Sokolov hierarchy tau function topological solution