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In-line response of vertical cylinders in regular and random waves

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Acta Oceanologica Sinica 2007年第6期26卷 124-138页

作者： LI Yok-sheung SU Wei ZHAN Jiemin ZHAN Sheng department of Civil ＆ Structural Engineering The Hong Kong Polytechnic UniversityHong Kong China department of applied Mechanics and Engineering Zhongshan University Guangzhou 510275 China

The in-line response of a vertical flexibly mounted cylinder in regular and random waves is reported. Both theoretical analyses and experimental measurements have been performed. The theoretical predictions are based on the Morison equation which is solved by the incremental harmonic balance method. Experiments are then performed in a wave flume to determine the accuracy of the Morison equation in predicting the in-line response of the cylinder in regular and random waves. The interaction between waves and vibrating cylinders are investigated.

关键词： in-line response cylinder waves IHB method

Environmental records of lacustrine sediments in different time scales:Sediment grain size as an example

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Science china Earth Sciences 2004年第10期47卷 954-960页

作者： CHEN Jing’an1, WAN Guojiang1, David Dian Zhang2, ZHANG Feng1 & HUANG Ronggui1 1. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, china 2. department of Geography and Geology, university of hong kong, Pokfulam Road, hong kong, china State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang China department of Geography and Geology University of Hong Kong Hong Kong China

Sediment grain size is a conventional proxy of climatic changes. Larger sediment grain size is often interpreted to indicate dry climate during lower lake level while smaller sedi- ment grain size implies wet climate during higher lake level. Through detailed study on sediment grain sizes in Lake Erhai and Lake Chenghai, this paper reveals the different indication signifi- cances of sediment grain sizes in different time scales, different resolution investigations. For long time-scale and low resolution (102a or 103a) studies, larger sediment grain size indicates lower lake level, smaller lake area and drier climate while smaller sediment grain size indicates higher lake level, larger lake area and wetter climate. For short time-scale and high resolution (a or 10a) studies, larger sediment grain size reflects more rainfall and wetter climate while smaller sediment grain size reflects less rainfall and drier climate. Environmental information revealed by lacustrine sediment records is often different in different time scales because of the variance of sedimentation resolution, sampling resolution and dating precision. Therefore, paleoclimate im- plications of environmental proxies in long time-scale and low resolution investigations could not be mechanically applied to short time-scale and high resolution studies. Only after synthetically analyzing the influence manner and extent of all factors on the sediment records in different time scales, can credible conclusions be obtained.

关键词： lacustrine sediment, environmental record, grain size, time scale.

THREE-DIMENSIONAL LARGE EDDY SIMULATION OF FREE SURFACE TURBULENT FLOW IN OPEN CHANNEL WITHIN SUBMERGED VEGETATION DOMAIN

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Journal of Hydrodynamics 2003年第3期15卷 35-43页

作者： SuXiao-hui LiC.W ChenBi-hong CollegeofCivilandHydraulicEngineering DalianUniversityofTechnologyDalian116024China departmentofCivilandStructuralEngineering HongKongPolytechnicUniversityHongKongChina

A three-dimensional Large Eddy Simulation (LES) has been performed ofhydrodynamic behavior of turbulent flow in open channel that the lower part of the domain isoccupied by a drag force layer to represent vegetation. One equation model is used to closing theresolvable scale equations. The turbulent characteristic length is parameterized by a k-l model. Aphenomenal model is employed to express the performance of vegetation in the open channel. Theresult reveals that the present model has the capacity of describing three-dimensional structure oflarge eddy appearing in turbulent flow in open channel with vegetation region and has the capacityof tracing the development of large eddies.

关键词： LES turbulent flow open channel vegetation

An Improved Golden Jackal Optimization Algorithm Based on Multi-strategy Mixing for Solving Engineering Optimization Problems

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Journal of Bionic Engineering 2024年第2期21卷 1092-1115页

作者： Jun Wang Wen-chuan Wang Kwok-wing Chau Lin Qiu Xiao-xue Hu hong-fei Zang Dong-mei Xu College of Water Resources North China University of Water Resources and Electric PowerZhengzhou450046People’s Republic of China department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong KongPeople’s Republic of China

Nowadays,optimization techniques are required in various engineering domains to find optimal solutions for complex *** a result,there is a growing tendency among scientists to enhance existing nature-inspired algorithms using various evolutionary strategies and to develop new nature-inspired optimization methods that can properly explore the feature *** recently designed nature-inspired meta-heuristic,named the Golden Jackal Optimization(GJO),was inspired by the collaborative hunting actions of the golden jackal in nature to solve various challenging ***,like other approaches,the GJO has the limitations of poor exploitation ability,the ease of getting stuck in a local optimal region,and an improper balancing of exploration and *** overcome these limitations,this paper proposes an improved GJO algorithm based on multi-strategy mixing(LGJO).First,using a chaotic mapping strategy to initialize the population instead of using random parameters,this algorithm can generate initial solutions with good diversity in the search ***,a dynamic inertia weight based on cosine variation is proposed to make the search process more realistic and effectively balance the algorithm's global and local search ***,a position update strategy based on Gaussian mutation was introduced,fully utilizing the guidance role of the optimal individual to improve population diversity,effectively exploring unknown regions,and avoiding the algorithm falling into local *** evaluate the proposed algorithm,23 mathematical benchmark functions,CEC-2019 and CEC2021 tests are *** results are compared to high-quality,well-known optimization *** results of the proposed method are compared from different points of view,including the quality of the results,convergence behavior,and *** superiority and high-quality performance of the proposed method are demonstrated by comparing the ***,to demonstrate

关键词： Golden jackal optimization Chaotic mapping Dynamic inertia weight Dimensional Gaussian variation Muskingum

A kernel learning framework for domain adaptation learning

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Science china(Information Sciences) 2012年第9期55卷 1983-2007页

作者： TAO JianWen 1,3,CHUNG FuLai 2 & WANG ShiTong 1,2 1 School of Digital Media,Jiangnan university,Wuxi 214122,china 2 department of Computing,hong kong polytechnic university,hong kong,china 3 School of Information Engineering,Zhejiang Business Technology Institute,Ningbo 315012,china School of Digital Media Jiangnan University Wuxi China School of Information Engineering Zhejiang Business Technology Institute Ningbo China department of Computing Hong Kong Polytechnic University Hong Kong China

Domain adaptation learning(DAL) methods have shown promising results by utilizing labeled samples from the source(or auxiliary) domain(s) to learn a robust classifier for the target domain which has a few or even no labeled ***,there exist several key issues which need to be addressed in the state-of-theart DAL methods such as sufficient and effective distribution discrepancy metric learning,effective kernel space learning,and multiple source domains transfer learning,*** at the mentioned-above issues,in this paper,we propose a unified kernel learning framework for domain adaptation learning and its effective extension based on multiple kernel learning(MKL) schema,regularized by the proposed new minimum distribution distance metric criterion which minimizes both the distribution mean discrepancy and the distribution scatter discrepancy between source and target domains,into which many existing kernel methods(like support vector machine(SVM),v-SVM,and least-square SVM) can be readily *** framework,referred to as kernel learning for domain adaptation learning(KLDAL),simultaneously learns an optimal kernel space and a robust classifier by minimizing both the structural risk functional and the distribution discrepancy between different ***,we extend the framework KLDAL to multiple kernel learning framework referred to as *** the KLDAL or MKLDAL framework,we also propose three effective formulations called KLDAL-SVM or MKLDAL-SVM with respect to SVM and its variant μ-KLDALSVM or μ-MKLDALSVM with respect to v-SVM,and KLDAL-LSSVM or MKLDAL-LSSVM with respect to the least-square SVM,*** experiments on real-world data sets verify the outperformed or comparable effectiveness of the proposed frameworks.

关键词： domain adaptation learning support vector machine multiple kernel learning maximum mean discrepancy maximum scatter discrepancy

AN IMPROVED EFFICIENT SEMI-IMPLICIT FINITE ELEMENT SCHEME FOR TWO-DIMENSIONAL TIDAL FLOW COMPUTATIONS

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Journal of Hydrodynamics 1991年第1期3卷 56-65页

作者： Chen Chu-ping, department of applied Mechanics and Engineering, Zhongshan university, Guangzhou 510275, P.R. chinaY.S. Li, department of Civil & Structural Engineering, hong kong polytechnic, hong kong

In a recent paper, an efficient semi-implicit finite element scheme for 2-dimensional tidal flow computations is proposed. In that scheme, each term of the governing equations, rather than each dependent variable, is ex- panded in terms of the unknown nodal values. Simpson's rule ix used for numerical integration to make the mass matrix diagonal. The friction terms are represented semi-implicitly to improve stability, but no additional compu- tational effort is required. The shortcomings of this scheme are that the time-stepping scheme is only first-order ae- curate and artificial smoothing is required to control the numerical noise. In this paper, the previous scheme is im- proved by including the eddy viscosity terms in the governing equations to replace artificial smoothing in noise con- trol and the time-stepping scheme is modified to make it second-order accurate. These improvements can be achieved with only a slight increase in computational effort. The test cases used previously to validate the former scheme are again employed to test the present scheme.

关键词： Flow AN IMPROVED EFFICIENT SEMI-IMPLICIT FINITE ELEMENT SCHEME FOR TWO-DIMENSIONAL TIDAL FLOW COMPUTATIONS SEMI

Equivalent distributed capacitance model of oxide traps on frequency dispersion of C-V curve for MOS capacitors

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Chinese Physics B 2016年第11期25卷 645-651页

作者：卢汉汉徐静平刘璐黎沛涛邓咏雯 School of Optical and Electronic Information Huazhong University of Science and Technology department of Electrical and Electronic Engineering The University of Hong Kong department of applied Physics The Hong Kong Polytechnic University

An equivalent distributed capacitance model is established by considering only the gate oxide-trap capacitance to explain the frequency dispersion in the C-V curve of MOS capacitors measured for a frequency range from 1 kHz to1 *** proposed model is based on the Fermi-Dirac statistics and the charging/discharging effects of the oxide traps induced by a small ac *** validity of the proposed model is confirmed by the good agreement between the simulated results and experimental *** indicate thatthe capacitance dispersion of an MOS capacitor under accumulation and near flatband is mainly caused by traps adjacent to the oxide/semiconductor interface,with negligible effects from the traps far from the interface,and the relevant distance from the interface at which the traps can still contribute to the gate capacitance is also *** addition,by excluding the negligible effect of oxide-trap conductance,the model avoids the use of imaginary numbers and complex calculations,and thus is simple and intuitive.

关键词： capacitance conductance intuitive negligible imaginary validity explain capacitor biased leakage

PARTITION PROPERLY OF DOMAIN DECOMPOSITION WITHOUT ELLIPTICITY

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Journal of Computational mathematics 2001年第4期19卷 423-432页

作者： Mo Mu (Deportment of mathematics, The hong kong university of Science and Technology, Clear Water Bay, Kowloon, hong kong) Yun-qing Huang (department of mathematics, Xiangtan university, Xiangtan 411105, china) 香港科技大学香港湘潭大学湖南湘潭 411105

Partition property plays a central role in domain decomposition methods. Existing theory essentially assumes certain ellipticity. We prove the partition property for prod lems without ellipticity which are of practical importance. Example applications include implicit schemes applied to degenerate parabolic partial differential equations arising from superconductors, superfluids and liquid crystals. With this partition property, Schwarz algorithms can be applied to general non-elliptic problems with an h-independent optimal convergence rate. Application to the time-dependent Ginzburg-Landau model of superconductivity is illustrated and numerical results are presented.

关键词： Partition property Domain decomposition Non-ellipticity Degenerate parabolic problems Time-dependent Ginzburg-Landau model Superconductivity Preconditioning Schwarz algorithms.

Spectrum characteristics and pump wavelengths of Nd_(3+) -doped double-clad fiber

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Chinese Science Bulletin 1997年第11期42卷 897-900页

作者： MING Hai, YANG Bao, DONG Xiaopeng, A. Fedotov, Xudong Xiao and M. M. T. Loy1. department of Physics, university of Science and Technology of china, Hefei 230026, china 2. department of Physics, university of Science and Technology of hong kong, hong kong, china department of Physics University of Science and Technology of China Hefei China department of Physics University of Science and Technology of Hong Kong Hong Kong China

Nd3+ -doped double-clad fiber is a new type of fiber that has large *** large receivingarea compared with single-clad rare-earth-doped *** Nd3+-doped double-clad fiberpumped directly by laser-diode arrays can be manufactured into high-power fiber lasers,high-power superfluorescence sources and high-gain fiber amplifiers,and they will be applied

关键词： double-clad fiber optimum pump wavelength optical spectrum.