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Credit Determination of Fibre Channel in Avionics Environment

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Chinese Journal of Aeronautics 2007年第3期20卷 247-252页

作者： LIN Qiang XIONG hua-gang zhang Qi-shan School of Electronic and Information Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China

Fibre channel （FC） is the main candidate architecture for ＂unified network＂. Flow control deals with the problem in which a device receives frames faster than it can process them. Credit is an important service parameter for fibre channel flow control. Configuring the credit reasonably can avoid buffer overflow in nodes. This paper derives the mathematic relationships among credit, bandwidth and message sets under real-time condition according as three main topologies of fibre channel, and proposes the credit determination and the optimal credit for typical message sets. This study is based on the features of hard real-time communications in avionics environment.

关键词： fibre channel topology login credit hard real-time condition

Design of Robot Welding Seam Tracking System with Structured Light Vision

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Chinese Journal of Mechanical Engineering 2010年第4期23卷 436-442页

作者： LIU Suyi WANG Guorong zhang hua JIA Jianping Provincial Key Lab of Robot and Weld Automation Nanchang University Nanchang 330031 China School of Mechanical andAutomotive Engineering South China University of Technology Guangzhou 510640 China

Robot welding is an important developing direction of welding automation and intelligentization, and automatic seam tracking technology is one of principal research domains. Nowadays, seam tracking system with structured light vision becomes a hot research. Structured light vision seam tracking products abroad are generally very expensive and can only be applied on special occasions. In China, the research of structured light vision seam tracking system is still just on the stage of experiments. A robot real-time seam tracking system with line structured light vision is designed. The hardware system is set up, a filtering method for line structure seam image is improved, and compared with common filtering, it has better effect and characteristic of real time. Two methods, fast template matching and fast Hough transform, to recognize the image coordinates of seam center are improved. Two new image recognition methods, structure element matching and comer detecting, are proposed. The comparison of seam image recognition shows that fast template matching and comer detecting are more precise and stable than the other two methods, and comer detecting is the best in real time. A simultaneous calibration for camera parameters and robot hand-eye is also proposed, and calculation shows that the calibration is effective and feasible. The robot seam tracking tests for linear and folded lap-joint are performed, which are based on the above four image recognition methods, and the results indicate that four image recognition methods are all applicable to real-time seam tracking, and the whole system sufficed for the requirements of real-time seam tracking. Automatic seam tracking with line structured light vision is feasible and has good versatility.

关键词： laser vision robot seam tracking image recognition

A novel pairing-free certificateless authenticated key agreement protocol with provable security

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Frontiers of Computer Science 2013年第4期7卷 544-557页

作者： Haiyan SUN Qiaoyan WEN hua zhang Zhengping JIN State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China

Recently, He et al. （Computers and Mathematics with Applications, 2012） proposed an efficient pairing-free certificateless authenticated key agreement （CL-AKA） protocol and claimed their protocol was provably secure in the extended Canetti-Krawczyk （eCK） model. By giving concrete attacks, we indicate that their protocol is not secure in the eCK model. We propose an improved protocol and show our improvement is secure in the eCK model under the gap DiffieHellman （GDH） assumption. Furthermore, the proposed protocol is very efficient.

关键词： attacks pairings eCK model provable security,certificateless authenticated key agreement

Pseudospectral method for optimal propellantless rendezvous using geomagnetic Lorentz force

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Applied Mathematics and Mechanics(English Edition) 2015年第5期36卷 609-618页

作者： Xu huaNG Ye YAN Yang ZHOU hua zhang College of Aerospace Science and Engineering National University of Defense Technology Department of Communication Beijing Aerospace Control Center

A charged spacecraft is subject to the Lorentz force when it orbits a central body with a magnetic field. The induced Lorentz force provides a new mean of propellantless electromagnetic propulsion for orbital control. Modeling the Earth magnetic field as a tilted dipole that co-rotates with the Earth, this paper develops a nonlinear dynamical model that describes the relative motion of the Lorentz spacecraft about an arbitrary reference orbit. Based on the proposed dynamical model, feasibility of Lorentz-propelled rendezvous with no restrictions on the initial states is investigated. The rendezvous problem is then formulated as an optimal control problem, and solved with the Gauss pseudospectral method（GPM）. Numerical simulations substantiate the validity of proposed model and method, and results show that the propellantless rendezvous is achieved at both fixed and free final time.

关键词： Lorentz dynamical dipole spacecraft propulsion validity orbital integer formulated constraints

Design and motion testing of a Multiple SMA fin driven BIUV

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Journal of Hydrodynamics 2019年第1期31卷 124-136页

作者： Yong-hua zhang Jian-hui He Kinhuat Low Department of Mechatronics Engineering Taizhou Vocational and Technical CollegeTaizhou 318000China School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore

Fishes interact with the fluid environment using various *** multiple control surfaces work in combination to produce the thrust and the balance torques in a steady swimming,to maneuver and to position themselves accurately even in turbulent *** motivate us to embark on a research program designed to develop an agile biologically inspired robotic fish based on the performance of multiple *** accomplish this goal,a mechanical ray-like fin actuated by the shape memory alloy (SMA) is developed,which can realize the oscillating motion,the undulating motion or even the complex three dimensional *** basic unit is the two opposite side SMA-driven plate,namely the fin *** a result,a lightweight bio-inspired fin is constructed by placing radially multiple SMA fin rays.A biologically inspired underwater vehicle (BIUV) is later built using the above multiple lightweight bio-inspired *** common arrangement styles of multiple fins on the BIUV are considered here:one is the posterior fin (for the oscillating motion) that is parallel to the anterior fins (for the undulating motion),another one is the posterior fin that perpendicular to the anterior *** kinematic modeling,the deformation modeling and the detecting of the SMA fin are *** thrust generation is also ***,an experiment is conducted to test the performance of the proposed two arrangement styles,including the comparison of the averaged propulsion velocity and the averaged thrust under certain kinematic ***,the influence of the frequency and the amplitude of the SMA fin ray on the propulsion performance is also investigated.

关键词： Oscillating undulating shape memory alloy (SMA) biologically inspired underwater vehicle (BIUV) fin ray

Hierarchical porous carbon derived from one-step self-activation of zinc gluconate for symmetric supercapacitors with high energy density

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Frontiers of Chemical Science and Engineering 2023年第4期17卷 387-394页

作者： Junlei Xiao hua zhang Yifan Wang Chunmei zhang Shuijian He Shaohua Jiang Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources International Innovation Center for Forest Chemicals and MaterialsCollege of Materials Science and EngineeringNanjing Forestry UniversityNanjing 210037China College of Chemistry and Chemical Engineering Jiangxi Normal UniversityNanchang 330022China Institute of Materials Science and Devices School of Materials Science and EngineeringSuzhou University of Science and TechnologySuzhou 215009China

Porous carbons with high specific area surfaces are promising electrode materials for ***,their production usually involves complex,time-consuming,and corrosive ***,a straightforward and effective strategy is presented for producing highly porous carbons via a self-activation procedure utilizing zinc gluconate as the *** volatile nature of zinc at high temperatures gives the carbons a large specific surface area and an abundance of mesopores,which avoids the use of additional activators and ***,the obtained porous carbon electrode delivers a satisfactory specific capacitance and outstanding cycling durability of 90.9%after 50000 cycles at 10 A·g^(-1).The symmetric supercapacitors assembled by the optimal electrodes exhibit an acceptable rate capability and a distinguished cycling stability in both aqueous and ionic liquid ***,capacitance retention rates of 77.8%and 85.7%are achieved after 50000 cycles in aqueous alkaline electrolyte and 10000 cycles in ionic liquid ***,the symmetric supercapacitors deliver high energy/power densities of 49.8 W·h·kg^(-1)/2477.8 W·kg^(-1) in the Et4NBF4 electrolyte,outperforming the majority of previously reported porous carbon-based symmetric supercapacitors in ionic liquid electrolytes.

关键词： self-activation zinc organic salts abundant mesopores symmetric supercapacitor liquid electrolyte

NewBalance: Efficient Data Space Management and Algorithmic Optimization for Large-Scale Storage Systems

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Chinese Journal of Electronics 2017年第3期26卷 493-501页

作者： XU Guangping LIN Sheng SHI Kai zhang hua Tianjin Key Laboratory of Intelligence Computing and New Software Technology Computer and Communication Engineering School Tianjin University of Technology

Fragmentation usually occurs when data space of original storage nodes has to be reallocated to new added storage nodes during the scale-out evolution of the large-scale storage *** greatly influences its performance and becomes a challenge to manage the whole *** present an efficient space management framework,called New Balance,to reduce fragmentation with the minimum data movement while keeping the storage system load *** space management framework has two phases including the collection phase and the allocation *** the collection phase,we propose a novel algorithm,called the greedy bi-direction collector,which collects enough space for the new storage *** the allocation phase,we formally represent it as a variant of the bin packing problem and then utilize some bin packing heuristics including the first fitting and the best fitting to allocate collected intervals to new added storage *** experimental results show that the amount of intervals can be reduced by 20%;5%and our algorithmic optimization improves the data lookup performance by at least 10%and the scale-out performance by 2X;X.

关键词： Large-scale storage systems Space management Algorithmic optimization Performance evaluation

Estimating source strengths of HCl and SO_2 emissions in the flue gas from waste incineration

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Journal of Environmental Sciences 2019年第1期31卷 370-377页

作者： hua zhang Siyuan Yu Liming Shao Pinjing He State Key Laboratory of Pollution Control and Resource Reuse Tongji University Institute of Waste Treatment & Reclamation College of Environmental Science and Engineering Tongji University Shanghai Institute of Pollution Control and Ecological Security Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area Ministry of Housing and Urban-Rural Development

HCl and SO_2 emission is one of the major concerns related to municipal solid waste incinerator(MSWI). In this study, a material flow analysis model was developed to estimate the HCl and SO_2 concentrations in the MSWI flue gases(FGs), and their concentrations in the full-scale MSWI were monitored. The calculated concentrations of HCl and SO_2 in the FG were 770–1300 mg/Nm^3 and 150–640 mg/Nm^3, respectively, in close agreement with the monitored values. More than 99% of Cl and 92% of S from the FG were captured into solid residues by the air pollution control(APC) systems. Moreover, since only 48.4%–67.5% of Cl and 21.3%–53.4% of S were transferred to the FG from the municipal solid waste(MSW), it was more reliable to estimate the source strengths and release amounts of HCl and SO_2 in the FG based on the amounts of Cl and S in the APC residues(AR) and exhaust gas rather than in the MSW. This simple method is easily applicable and the estimated results could provide scientific basis for the appropriate design and operation of the APC systems as well as corrosion control of heat recovery systems.

关键词： Municipal solid waste incineration Acid gas Hydrogen chloride Sulfur dioxide Source strength

Code acquisition method based on wavelet transform filtering

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Journal of Systems Engineering and Electronics 2015年第6期26卷 1169-1176页

作者： Chao Wu Luping Xu hua zhang Wenbo Zhao School of Aerospace Science and Technology Xidian University

In order to improve the acquisition probability of satellite navigation signals, this paper proposes a novel code acquisition method based on wavelet transform filtering. Firstly, the signal vector based on the signal passing through a set of partial matched filters （PMFs） is built. Then, wavelet domain filtering is performed on the signal vector value. Since the correlation signal is low in frequency and narrow in bandwidth, the noise out-of-band can be filtered out and the most of the useful signal energy is retained. Thus this process greatly improves the signal to noise ratio （SNR）. Finally, the detection variable when the filtered signal goes through the combination process is constructed and the detection based on signal energy is made. Moreover, for the better retaining useful signal energy, the rule of selection of wavelet function has been made. Simulation results show the proposed method has a better detection performance than the normal code acquisition methods under the same false alarm probability.

关键词： code acquisition wavelet transform filtering detection probability.