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CHINESE JOURNAL OF AERONAUTICS 2024年第12期37卷 212-230页

作者： Huang, Ying Zhang, Jianguo Fan, Xiaoduo Gong, Qi Song, Lukai Beihang Univ Sch Reliabil & Syst Engn Beijing 100191 Peoples R China AVIC Aero polytechnol Estab Beijing 100028 Peoples R China hong kong polytech Univ Dept Mech Engn Hong Kong 100872 Peoples R China Beihang Univ Res Inst Aeroengine Beijing 102206 Peoples R China

Estimating the failure probability of highly reliable structures in practice engineering, such as aeronautical components, is challenging because of the strong-coupling and the small failure probability traits. In this paper, an Expanded Learning Intelligent Back Propagation (EL-IBP) neural network approach is developed: firstly, to accurately characterize the engineering response coupling relationships, a high-fidelity Intelligent-optimized Back Propagation (IBP) neural network metamodel is developed;furthermore, to elevate the analysis efficacy for small failure assessment, a novel expanded learning strategy for adaptive IBP metamodeling is proposed. Three numerical examples and one typical practice engineering case are analyzed, to validate the effectiveness and engineering application value of the proposed method. Methods comparison shows that the ELIBP method holds significant efficiency and accuracy superiorities in engineering issues. The current study may shed a light on pushing the adaptive metamodeling technique deeply toward complex engineering reliability analysis. (c) 2024 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics. This is an open access article under the CC BY-NC-ND license (http://***/ licenses/by-nc-nd/4.0/).

关键词： Reliability analysis Back propagation neural network Adaptive metamodel Variance expansion Small failure probability Strong-coupling

Low C/N_0 Carrier Tracking Loop Based on Optimal Estimation Algorithm in GPS Software Receivers

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Chinese Journal of Aeronautics 2010年第1期23卷 109-116页

作者： Miao Jianfeng Chen Wu Sun Yongrong Liu Jianye Navigation Research Center College of Automation Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016 China Department of Land Surveying and Geo-informatics Hong Kong Polytechnic UniversityHong Kong China

Suppressing jitter noises in a phase locked loop（ PLL） is of great importance in order to keep precise and continuous track of global positioning system （GPS）signals characterized by low carrier-to-noise ratio（ C/No ）. This article proposes and analyzes an improved Kalman-filter-based PLL to process weak carrier signals in GPS software receivers. After reviewing the optimal-bandwidth-based traditional second-order PLL, a Kalman-filter-based estimation algorithm is implemented for the new PLL by decorrelating the model error noises and the measurement noises. Finally,the efficiency of this new Kalman-filter-based PLL is verified by experimental data. Compared to the traditional second-order PLL, this new PLL is in position to make correct estimation of the carrier phase differences and Doppler shifts with less overshoots and noise disturbances and keeps an effective check on the disturbances out of jitter noises in PLL. The results show that during processing normal signals,this improved PLL reduces the standard deviation from 0. 010 69 cycle to 0. 007 63 cycle, and for weak signal processing,the phase jitter range and the Doppler shifts can be controlled within ± 17° and ±5 Hz as against ±25° and ＋ 15 Hz by the traditional PLL.

关键词： global positioning system signal processing Kalman filters software radio phase locked loop

Integral ear elimination and virtual point-based updating algorithms for constrained Delaunay TIN

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Science China(Technological Sciences) 2008年第S1期51卷 135-144页

作者： WU LiXin1,2,WANG YanBing2,3 & SHI WenZhong2,4 1 Institute for Geo-informatics & Digital Mine Research,Northeastern University,Shenyang 110004,China 2 Institute for GIS/RS/GPS & Subsidence Engineering Research,China University of Mining & Technology,Beijing 100085,China 3 Laboratory of 3D Information Acquisition & Application,Capital Normal University,Beijing 100037,China 4 Center for Advanced GIS Research,LSGI,polytechnic University hong kong,hong kong,China Northeastern Univ Inst Geoinformat & Digital Mine Res Shenyang 110004 Peoples R China China Univ Mining & Technol Inst GIS RS GPS & Subsidence Engn Res Beijing 100085 Peoples R China Capital Normal Univ Lab Informat Acquisit & Applicat Beijing 100037 Peoples R China hong kong polytech Univ LSGI Ctr Adv GIS Res Hong Kong Hong Kong Peoples R China

Constrained Delaunay Triangular Irregular Networks (CD-TIN),a kind of special data structure,have many practical applications in Geoinformatics,especially in the representation of linear constrained triangulation for DTM and DSM,such as in digital city and digital mine. Past researches on D-TIN mainly focused on point in-sertion and deletion without consideration of constraint,and that on CD-TIN usu-ally paid more attention to the insertion algorithms for points and edges,but little to the deletion algorithms. The presented algorithms are far insufficient for the dy-namic updating of CD-TIN. In this paper,the constraint edge in CD-TIN is consid-ered to be any set of broken lines,i.e.,polygon edges,broken lines and simple segments. The constraint edge may be composed of one or more constraint seg-ments,and it is allowed to be in any form: Open or close,intersection or self-in-tersection. By improving to present insertion and deletion algorithms for D-TIN,two new algorithms for CD-TIN updating are presented. According to the polymorphism of the constraints in CD-TIN,virtual point is adopted to represent the crossing node between constraint edges when a constraint edge is inserted in CD-TIN. Two new algorithms named as Integral Ear Elimination (IEE) and Influence Domain Retrian-gulation for Virtual Point (IDRVP) are presented,the former is for constraint point deletion,while the later is for the insertion and deletion of constraint edge. The principle of IDRVP is that to divide the influence domain of a virtual point into some parts by the constraint-keeping edges,and to retriangulate each part of the influ-ence domain individually referring to the constraint visible property and constraint empty circle (CEC) criterion. Finally,a prototype system is developed with VC++,one case on the integration of 3D terrain and buildings is demonstrated to test the correctness of new algorithms. It shows that the new algorithms are effective for the updating of CD-TIN.

关键词： Delaunay TIN spatial constraint data updating spatial modeling polymorphism digital mine

A Review on Signal Compression of Spectroscopic Data in Analytical Chemistry

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物理化学学报 1997年第9期13卷 857-864页

作者： Leung Kai-man Chau Foo-tim(Department of Applied Biology and Chemical Technology The hong kong polytechnic University Hung Hom, Kowloon, hong kong) Dept. Appl. Biol. and Chem. Technol. Hong Kong Polytech. Univ. Hung Hom Kowloon Hong Kong

Abstract:Chedrical instruments are widely used in modern analytical chedristry for chedrical analysis. However, modern chemical instruments especially the hyphenated instruments generate huge anount of data in each measurement. Data compression techniques are required to reduce the data for storage and further analysis. In this paper, data compression techniques commonly applied to analytical chemistry are reviewed.

关键词： Chemical instruments Analytical chemistry Data compression techniques

Fuzzy Adaptive State Estimation of Distributed Drive Electric Vehicles with Random Missing Measurements and Unknown Process Noise

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CHINESE JOURNAL OF MECHANICAL ENGINEERING 2024年第1期37卷 1-12页

作者： Zhang, Zhiguo Yin, Guodong Huang, Chao Hu, Jingyu Xu, Xing Jiang, Chengyue Wang, Yan Southeast Univ Sch Mech Engn Nanjing 211189 Peoples R China hong kong polytech Univ Dept Ind & Syst Engn Hong Kong Peoples R China Jiangsu Univ Dept Automot Engn Res Inst Zhenjiang 225009 Peoples R China Chongqing Univ Technol Coll Vehicle Engn Chongqing 400054 Peoples R China

Accurate estimation of sideslip angle and vehicle velocity is crucial for effective control of distributed drive electric vehicles. However, as these states are not directly measured, Kalman-based approaches utilizing in-vehicle sensors have been developed to estimate them. Unfortunately, existing methods tend to ignore the impact of data loss on estimation performance. Furthermore, the process noise, which changes dynamically due to varying driving conditions, is not adequately considered. In response to these constraints, we propose a novel method called the fuzzy adaptive fault-tolerant extended Kalman filter (FAFTEKF). Initially, a fault-tolerant EKF is devised to handle missing measurements. Additionally, a fuzzy logic system that dynamically updates the process noise matrix, is built to improve estimation accuracy under different driving conditions. Extensive experimental results validate the superiority of the FAFTEKF over the traditional EKF across various scenarios with different degrees of data loss.

关键词： Distributed drive electric vehicles State estimation Fault-tolerant EKF Fuzzy logic system

Synergetic analysis of springtime air pollution episodes over Gwangju,Korea

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Journal of Environmental Sciences 2017年第7期29卷 270-283页

作者： Sung-Kyun Shin Kwon-Ho Lee Seung-Shik Park Man Sing Wong Research Institute for Radiation-Satellite(RIRS) Gangneung-Wonju National University(GWNU)Gangneung 25457Republic of Korea Department of Atmospheric and Environmental Sciences(DAES) Gangneung-Wonju National University(GWNU)Gangneung 25457Republic of Korea Department of Environment and Energy Engineering Chonnam National UniversityGwangju 61186Republic of Korea Department of Land Surveying and Geo-Informatics The Hong Kong Polytech UniversityKowloonHong Kong

The characteristics of springtime aerosols,including their optical and microphysical properties,were analyzed for the months of March to May of 2009 in Gwangju（35.23°N,126.84°E）,Korea.A high Light Detection and Ranging（LIDAR）-derived aerosol depolarization ratio（δ） of 0.25 ± 0.04 was determined on dust particles during the observation ***？ngstr？m exponent values of the 440–870 nm wavelength pair（？_（440–870）） and single-scattering albedo at 675 nm（Ω_（675）） measured by a CIMEL sun/sky radiometer were 0.77 ± 0.19 and 0.95 ±0.01,*** elevated dust layers reached a maximum elevation of 4 km above sea ***/smoke particles that originated from highly populated/industrialized regions could be distinguished by their relatively smaller particle size（？_（440–870） ranged between1.33 and 1.36） and higher light-absorbing（Ω_（675） of 0.92 ± 0.01） *** aerosols are mostly distributed at altitudes 〈 1.2 *** root-mean-square deviation（RMSD） between the aerosol optical depth（AOD,τ） derived from LIDAR_（（τ_（LIDAR））） and from the CIMEL sun/sky radiometer_（（τ_（CIMEL））） varied with respect to the surface PM10 *** RMSD between τ_（LIDAR） and τ_（CIMEL） was as low as 13% under lower PM_（10） concentration levels（〈 100 μg/m^3）.In contrast,the RMSD between τ_（LIDAR） and τ_（CIMEL） increased three times（~31%） under high surface PM_（10） concentration levels（〉100 μg/m^3）.These results suggest that the accuracy of τ_（LIDAR） is influenced by specific atmospheric conditions,regardless of its uncertainty.

关键词： LIDAR Sun/sky radiometer MODIS Optical/microphysical properties Aerosol optical depth

Optical and thermal performance analysis of aerogel glazing technology in a commercial building of hong kong

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Energy and Built Environment 2020年第2期1卷 215-223页

作者： C.K.Leung L.Lu Y.Liu H.S.Cheng Jeff H.Tse Department of Building Services Engineering The Hong Kong Polytechnic UniversityZS850Block ZHung HomKowloonHong KongChina College of Civil Engineering Hunan UniversityChangshaHunan 410082China Electrical and Mechanical Services Department HKSARHong KongChina

Improving the thermal insulation of glazing units is a common strategy of reducing building energy use for spacing *** paper newly examined the application of aerogel glazing technology in hong kong by the means of laboratory testing and *** prototypes of granular aerogel glazing were selected to examine their optical properties,and the measured optical properties of aerogel were used to calculate the total window thermal performance indices.A typical 40-story commercial office building was chosen for energy simulation to compare the thermal performance of aerogel glazing with different glazing technologies in hong *** results showed that aerogel glazing could achieve the promising reduction of window heat gain up to 57%and cooling energy up to 8.5%compared with double *** heat insulation performance of aerogel glazing is even better than the double glazing with low-E coating in hong ***,aerogel glazing can be a good alternative of glazing to comply with the existing local Overall Thermal Transfer Value(OTTV)requirement and to reduce the building energy use for space cooling in hong kong and other regions.

关键词： Glazing technology Aerogel glazing Building energy saving

NUMERICAL STUDY ON THE MIXING OF UNSORTED SEDIMENT PARTICLES DISCHARGED INTO A CROSS-FLOW BY MULTIPHASE PARTICLE-IN-CELL (MP-PIC) METHOD

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International Journal of Sediment Research 2007年第2期22卷 150-159页

作者： Jie GU1, Chiwai LI2, hong YANG1 and Yong ZHAN31 Department of Environmental Engineering, College of Marine Science and Technology, Shanghai Fisheries University, 334 Jungong Road, Shanghai 200090, China2 Department of Civil and Structural Engineering, The hong kong polytechnic University, Hunghom, Kowloon, hong kong, China3 Department of Environmental Engineering, College of Urban Construction and Environment, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093, China Shanghai Fisheries Univ Coll Marine Sci & Technol Dept Environm Engn Shanghai 200090 Peoples R China hong kong polytech Univ Dept Civil & Struct Engn Kowloon Hong Kong Peoples R China Shanghai Univ Sci & Technol Coll Urban Construct & Environm Dept Environm Engn Shanghai 200093 Peoples R China

The mixing characteristics of dredged sediments of variable size discharged into cross-flow are studied by an Eulerian-Lagrangian method. A three-dimensional (3D) numerical model has been developed by using the modified k-ε parameterization for the turbulence in fluid phase/water and a Lagrangian method for the solid phase/sediments. In the model the wake turbulence induced by sediments has been included as additional source and sink terms in the k-ε model; and the trajectories of the sediments are tracked by the Lagrangian method in which the sediment drift velocities in cross-flow are computed by a multiphase particle-in-cell (MP-PIC) method and the diffusion process is approximated by a random walk model. The hydrodynamic behavior of dumped sediment cloud is governed by the total buoyancy on the cloud, the drag force on each particle and velocity of cross-flow. The cross-flow destroys more or less the double vortices occurred in stagnant ambience and dominates the longitudinal movement of sediment cloud. The computed results suggest satisfactory agreement by comparison with the experimental results of laboratory.

关键词： 3D numerical model Two-phase flow Eulerian-Lagrangian method Sediment particle cloud Cross-flow Multiphase particle-in-cell (MP-PIC) method

Flow field analysis and particle erosion of tunnel-slope systems under coupling between runoff and fast (slow) seepage

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DEEP UNDERGROUND SCIENCE AND ENGINEERING 2023年第4期3卷 385-398页

作者： Zhang, Shuai Song, Danqing Zhang, Ruiliang Zhang, Kai Zhao, Qi Sharma, Suraksha Tsinghua Univ Dept Hydraul Engn State Key Lab Hydrosci & Engn Key Lab Hydrosphere SciMinist Water Resources Beijing Peoples R China South China Univ Technol Sch Civil Engn & Transportat State Key Lab Subtrop Bldg Sci Guangzhou 510640 Guangdong Peoples R China Sichuan Univ Dept Geotech Engn State Key Lab Hydraul & Mt River Engn Chengdu Peoples R China Kunming Univ Sci & Technol Fac Civil Engn & Mech Kunming Yunnan Peoples R China hong kong polytech Univ Dept Civil & Environm Engn Hong Kong Peoples R China Norwegian Univ Sci & Technol Trondheim Norway

The presence of particles on the surface of a tunnel slope renders it susceptible to erosion by water flow, which is a major cause of soil and water loss. In this study, a nonlinear mathematical model and a mechanical equilibrium model are developed to investigate the distribution of flow fields and particle motion characteristics of tunnel slopes, respectively. The mathematical model of flow fields comprises three parts: a runoff region, a highly permeable soil layer, and a weakly permeable soil layer. The Navier-Stokes equation controls fluid motion in the runoff region, while the Brinkman-extended Darcy equation governs fast and slow seepage in the highly and weakly permeable soil layers, respectively. Analytical solutions are derived for the velocity profile and shear stress expression of the model flow field under the boundary condition of continuous transition of velocity and stress at the fluid-solid interface. The shear stress distribution shows that the shear stress at the tunnel-slope surface is the largest, followed by the shear stress of the soil interface, indicating that particles in these two locations are most vulnerable to erosion. A mechanical equilibrium model of sliding and rolling of single particles is established at the fluid-solid interface, and the safety factor of particle motion (sliding and rolling) is derived. Sensitivity analysis shows that by increasing the runoff depth, slope angle, and soil permeability, the erosion of soil particles will be aggravated on the tunnel-slope surface, but by increasing the particle diameter, particle-specific gravity, and particle stacking angle, the erosion resistance ability of the tunnel-slope surface particles will be enhanced. This study can serve as a reference for the analysis of surface soil and water loss in tunnel-slope systems. The particles on the tunnel-slope surface can be easily scoured under the action of water flow, which is one of the main causes of soil and water loss. A nonlinear math

关键词： particle erosion particle motion runoff-fast (slow) seepage coupling shear stress profile tunnel-slope system velocity profile

Separation of tryptophan enantiomers with molecularly imprinted polypyrrole electrode column

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Chinese Chemical Letters 2010年第3期21卷 353-356页

作者： Chen, Zhi Dong Wei, Jing Xuan Wang, Wen Chang kong, Yong Jiangsu polytech Univ Fac Chem & Chem Engn Changzhou 213164 Peoples R China

In this study,we have fabricated molecularly imprinted polypyrrole(PPy) packed electrode columns and investigated their effects on separation of tryptophan(Trp) enantiomers by using potential *** results indicate that the imprinted PPy electrode columns could efficiently enhance the L-Trp uptake and separate Trp enantiomers effectively,implying the great potential for the enantioselective recognition of other amino acids enantiomers.

关键词： Polypyrrole Electrode column Molecular imprinting Tryptophan enantiomers