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Application of Genetic Algorithms in Identification ofLinear Time-Varying System

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International Journal of Minerals,Metallurgy and Materials 2000年第1期14卷 58-62页

作者： Zhichun Mu KeLiu Zichao Wang Datai Yu D. Koshal D. Pearce Information engineering school, University of Science & Technology Beijing, Beijing 100083, China school of engineering, University of brighton, brighton, uk Univ Sci & Technol Beijing Informat Engn Sch Beijing 100083 Peoples R China brighton Univ Sch Engn Brighton E Sussex England

By applying genetic algorithms (GA) to on-line identification of linear time-varying systems; a number of modifications are made to the Simple Genetic Algorithm to improve the performance of the algorithm in identification applications. The simulation results indicate that the method is not only capable of following the changing parameters of the system, but also has improved the identification accuracy compared with that using the least square method.

关键词： genetic algorithm, system identification linear system

Cross-Domain Bilateral Access Control on Blockchain-Cloud Based Data Trading System

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Computer Modeling in engineering & Sciences 2024年第10期141卷 671-688页

作者： Youngho Park Su Jin Shin Sang uk Shin Electronics and Information Communications Research Center Pukyong National UniversityBusan48513Republic of Korea Department of Information Security Graduate SchoolPukyong National UniversityBusan48513Republic of Korea Division of Computer engineering Pukyong National UniversityBusan48513Republic of Korea

Data trading enables data owners and data requesters to sell and purchase *** the emergence of blockchain technology,research on blockchain-based data trading systems is receiving a lot of ***,to reduce the on-chain storage cost,a novel paradigm of blockchain and cloud fusion has been widely considered as a promising data trading ***,the fact that data can be used for commercial purposes will encourage users and organizations from various fields to participate in the data *** the data marketplace,it is a challenge how to trade the data securely outsourced to the external cloud in a way that restricts access to the data only to authorized users across multiple *** this paper,we propose a cross-domain bilateral access control protocol for blockchain-cloud based data trading *** consider a system model that consists of domain authorities,data senders,data receivers,a blockchain layer,and a cloud *** proposed protocol enables access control and source identification of the outsourced data by leveraging identity-based cryptographic *** the proposed protocol,the outsourced data of the sender is encrypted under the target receiver’s identity,and the cloud provider performs policy-match verification on the authorization tags of the sender and receiver generated by the identity-based signature ***,data trading can be achieved only if the identities of the data sender and receiver simultaneously meet the policies specified by each *** demonstrate efficiency,we evaluate the performance of the proposed protocol and compare it with existing studies.

关键词： Bilateral access control blockchain data sharing policy-match

MXene-based hybrid materials for electrochemical and photoelectrochemical H_(2) generation

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Journal of Energy Chemistry 2024年第6期93卷 111-125,I0004页

作者： Jun Young Kim Seung Hun Roh Chengkai Xia uk Sim Jung Kyu Kim school of Material Science and engineering North University of ChinaTaiyuan 030051China school of Chemical engineering Sungkyunkwan University(SKKU)2066Seobu-roJangan-guSuwon 16419Republic of Korea Hydrogen Energy Technology Laboratory Korea Institute of Energy Technology(KENTECH)NajuJeollanamdo 58330Republic of Korea SKKU Advanced Institute of Nano Technology(SAINT) Sungkyunkwan University(SKKU)2066Seobu-roJangan-guSuwon 16419Republic of Korea

The conversion of solar energy to produce clean hydrogen fuel through water splitting is an emerging strategy for efficiently storing solar energy in the form of solar *** aligns with the increasing global demand for the development of an ideal energy alternative to fossil fuels that does not emit greenhouse ***(EC) and photoelectrochemical(PEC) water splitting technologies have garnered significant attention worldwide for advanced hydrogen solar fuel production in recent *** achieve sustainable green H_(2) production,it is essential to create efficient catalyst materials that are low-cost and can replace expensive noble metal-based *** characteristics make them an ideal catalyst material for the ***-dimensional MXenes with M_(n+1)X_(n) structure have been identified as a promising option for EC and PEC water splitting due to their superior hydrophilicity,metal-like conductivity,large surface area,and adjustable surface ***,we present a summary of recent advancements in the synthesis and performance enhancement methods for MXene hybrid materials in hydrogen production through EC and PEC water ***,we examine the challenges and insights associated with the rational design of MXene-based hybrid materials to facilitate efficient water splitting for sustainable solar fuel production.

关键词： MXene Hybrid materials EC PEC HER OER Water splitting

Fractal image compression based on fuzzy theory

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Journal of University of Science and Technology Beijing 2002年第3期9卷 228-232页

作者： Berthe Kya and Yang YangInformation engineering school, University of Science and Technology Beijing, Beijing 100083, China (Received 2001-11-13. Information engineering school University of Science and Technology Beijing Beijing 10083 China ***

Though progress has been made in fractal compression techniques, the longencoding times still remain the main drawback of this technique, which results from the need ofperforming a large number of range-domain matches. The total encoding time is the sum of the timerequired to perform each match. In order to make this method more efficient in practical use, thefuzzy theory based on feature extraction of the projection and normalized codebook method has beenprovided to optimize the encoding time, based on the c-means clustering approach. The results of theimplementation of Rate Mean Square (RMS), Peak signal noise ratio (PSNR) and the encoding time ofthis proposed method have been compared to other methods like the Feature Extraction andSelf-orgarnization methods to show its efficiency.

关键词： fractal compression fractal optimization fuzzy logic c-mean clusteringalgorithm hybrid fractal-fuzzy compression

Surface engineering of ZnO electrocatalyst by N doping towards electrochemical CO_(2) reduction

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Journal of Energy Chemistry 2024年第1期88卷 71-81,I0002页

作者： Rohini Subhash Kanase Getasew Mulualem Zewdie Maheswari Arunachalam Jyoti Badiger Suzan Abdelfattah Sayed Kwang-Soon Ahn Jun-Seok Ha uk Sim Hyeyoung Shin Soon Hyung Kang Department of Interdisciplinary Program for Photonic engineering Chonnam National UniversityGwangju 61186Republic of Korea Graduate school of Energy Science and Technology(GEST) Chungnam National University99 Daehak-roYuseong-guDaejeon 34134Republic of Korea Department of Chemistry Education and Optoelectronic Convergence Research Center Chonnam National UniversityGwangju 61186Republic of Korea Department of Advanced Chemicals and engineering Chonnam National UniversityGwangju 61186Republic of Korea school of Chemical engineering Yeungnam UniversityGyeongsan 38541Republic of Korea Department of Energy engineering Korea Institute of Energy Technology(KENTECH)Naju 58217Republic of Korea

The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-based electrocatalyst was developed for use in gas-diffusion electrodes(GDE),and the effect of nitrogen(N)doping on the ECR activity of ZnO electrocatalysts was ***,a ZnO nanosheet was prepared via the hydrothermal method,and nitridation was performed at different times to control the N-doping *** an increase in the N-doping content,the morphological properties of the nanosheet changed significantly,namely,the 2D nanosheets transformed into irregularly shaped ***,the ECR performance of Zn O electrocatalysts with different N-doping content was assessed in 1.0 M KHCO_(3) electrolyte using a gas-diffusion electrode-based ECR *** the ECR activity increased after a small amount of N doping,it decreased for higher N doping *** them,the N:ZnO-1 h electrocatalysts showed the best CO selectivity,with a faradaic efficiency(FE_(CO))of 92.7%at-0.73 V *** hydrogen electrode(RHE),which was greater than that of an undoped Zn O electrocatalyst(FE_(CO)of 63.4%at-0.78 V_(RHE)).Also,the N:ZnO-1 h electrocatalyst exhibited outstanding durability for 16 h,with a partial current density of-92.1 mA cm^(-2).This improvement of N:ZnO-1 h electrocatalyst can be explained by density functional theory calculations,demonstrating that this improvement of N:ZnO-1 h electrocatalyst comes from(ⅰ)the optimized active sites lowering the free energy barrier for the rate-determining step(RDS),and(ⅱ)the modification of electronic structure enhancing the electron transfer rate by N doping.

关键词： ZnO N-doped ZnO Gas-diffusion electrode CO Selectivity Electrochemical CO_(2)reduction

Three Dimensional Simulation of Upset Forging by Using Variational Upper Bound Method

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Journal of Materials Science & Technology 1994年第1期10卷 15-22页

作者： Jiang QIN(school of Mechanical engineering, University of Bath, Claverton Down, Bath BA27AY, uk) Univ of Bath Claverton Down Bath United Kingdom

The variation principle is discussed and Rayleigh-Ritz method is proposed for construction of veloci ty field. A kinematically admissible velocity field based on polynomials was appIied to the determina tion of forging load and deformed buIge profile during upset forging of blocks. Simulation of upsetforging of rectangular blocks under various friction condjtions was performed. Comparison of the computed results with experiments and FEM shows good agreement. It is shown that this techniquecan be used for 3D simulation of metal forming process.

关键词： Simulation Three Dimensional Simulation of Upset Forging by Using Variational Upper Bound Method ASME

AN ORDINARY DIFFERENTIAL EQUATION FOR THE 2D TRANSIENT FREE-SURFACE GREEN FUNCTIONS

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Journal of Hydrodynamics 2002年第2期14卷 24-28页

作者： Duan Wen-yang College of Shipbuilding engineering, Harbin engineering University, Harbin 150001, ChinaPrice W.G. school of engineering Sciences, Ship Science, University of Southampton, uk Coll. of Shipbuilding Eng. Harbin Eng. Univ. Harbin 150001 China Sch. of Eng. Sci. Ship Sci. Univ. of Southampton Southampton United Kingdom

Based on the Laplace transform an ordinary differential equation for the two-dimensional time-domain free-surface Green function in ship hydrodynamics is presented. The results for 2D Green function and its horizontal derivative are fifth-order ODEs and the vertical derivative satisfies a fourth-order ODE. All of these results may be used to accelerate the numerical computations for the time-domain BEM in marine hydrodynamics.

关键词： ship hydrodynamics time-domain Green function Laplace transform

Localized Corrosion in Copper Tubes by Volatile Organic Substance

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International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 129-132页

作者： Takenori Notoya(Laboratory of Corrosion engineering, Graduate school of engineering, Hokkaido University, Sapporo, Japan) Laboratory of Corrosion engineering Graduate School of Engineering Hokkaido University Sapporo Japan

An unusual form of localized corrsion in copper tubes was detected early in service and in leakage tests after *** morphology of this corrosion is similar to that of an ant's nest when viewed in cross section. The cor... 详细信息

关键词： copper tubes localized corrosion volatile organic substance heat-transfer units

RESEARCH OF DYNAMIC CHARACTERIATIC FOR TRANSMISSION SYSTEM

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Chinese Journal of Mechanical engineering 2001年第1期14卷 74-77页

作者： Qin Shuren school of Mechanical engineering,Chongqing University 重庆大学机械学院重庆

The kinetic precision of transmission chain is a key problem in the research of gear cutting machine transmission *** traditional point of view is to consider the transmission chain as a geometrical meshing system,thus it is deemed that the kinetic precision of the transmission chain only depends on the manufacturing and assembly errors of its transmission *** further research reveals that the kinetic precision of transmission system is closely related with the system dynamic ***,from the dynamic point of view,it is discerned that not only deems the transmission chain as a geometrical meshing system but also considers it as a dynamic system performing with torsional *** the basis of analyses and processes of measuring data of samples from tests of cutting machine's kinetic precision of transmission chain,the results represent that the influences of dynamic characteristics of the transmission system on its kinetic precision is non *** methods for discerning the transfer function of torsional vibration of gear transmission system and experimental results have been given.

关键词： Dynamic characteristics Gear Transmission system