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A Novel Model for Describing Rail Weld Irregularities and Predicting Wheel-Rail Forces Using a Machine Learning Approach

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 555-577页

作者： Linlin Sun Zihui Wang Shukun Cui Ziquan Yan Weiping Hu Qingchun Meng State Key Laboratory of High-Speed Railway Track system China Academy of Railway Sciences Corporation LimitedBeijing100081China Railway Engineering research Institute China Academy of Railway Sciences Corporation LimitedBeijing100081China School of Aeronautic Science and Engineering Beihang UniversityBeijing100191China

Rail weld irregularities are one of the primary excitation sources for vehicle-track interaction dynamics in modern high-speed *** can cause significant wheel-rail dynamic interactions,leading to wheel-rail noise,component damage,and *** researchers have employed the vehicle-track interaction dynamic model to study the dynamic interactions between wheel and rail induced by rail weld geometry ***,the cosine wave model used to simulate rail weld irregularities mainly focuses on the maximum value and neglects the geometric *** this study,novel theoretical models were developed for three categories of rail weld irregularities,based on measurements of the high-speed railway from Beijing to *** vertical dynamic forces in the time and frequency domains were compared under different running *** forces generated by the rail weld irregularities that were measured and modeled,respectively,were compared to validate the accuracy of the proposed ***,based on the numerical study,the impact force due to rail weld irrregularity is modeled using an Artificial Neural Network(ANN),and the optimum combination of parameters for this model is *** results showed that the proposed model provided a more accurate wheel/rail dynamic evaluation caused by rail weld irregularities than that established in the *** ANN model used in this paper can effectively predict the impact force due to rail weld irrregularity while reducing the computation time.

关键词： Rail weld irregularity high-speed railway vehicle-track coupled dynamics wheel/rail dynamic vertical force artificial neural networks

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Comparative simulation study of effects of eddy-topography interaction in the East/Japan Sea deep circulation

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Acta Oceanologica Sinica 2015年第7期34卷 1-18页

作者： CHOI Youngjin Center for Earth Information Science and Technology Japan Agency for Marine-Earth Science and Technology geo system research corporation

In this study the structure and seasonal variations of deep mean circulation in the East/lapan Sea （E/S） were numerically simulated using a mid-resolution ocean general circulation model with two different parameterizations for the eddy-topography interaction （ETI）. The strong deep mean circulations observed in the EIS are well reproduced when using the ETI parameterizations. The seasonal variability in the EIS deep layer is shown by using ETI parameterization based on the potential vorticity approach, while it is not shown in the statistical dynamical parameterization. The driving mechanism of the strong deep mean currents in the E/S are discussed by investigating the effects of model grids and parameterizations. The deep mean circulation is more closely related to the baroclinic process and potential vorticity than it is to the wind driven circulation.

关键词： East/Iapan Sea deep mean current seasonal variability ocean general circulation model eddy- topography interaction

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Non-negative matrix factorization based unmixing for principal component transformed hyperspectral data

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Frontiers of Information Technology & Electronic Engineering 2016年第5期17卷 403-412页

作者： Xiu-rui GENG Lu-yan JI Kang SUN Key Laboratory of Technology in geo-spatial Information Processing and Application system Institute of Electronics Chinese Academy of Sciences Beijing 100190 China MOE Key Laboratory for Earth system Modeling Center for Earth System Science Tsinghua University Beijing 100084 China The 54th research Institute of China Electronics Technology Group corporation Shijiazhuang 050000 China

Non-negative matrix factorization(NMF) has been widely used in mixture analysis for hyperspectral remote sensing. When used for spectral unmixing analysis, however, it has two main shortcomings:(1) since the dimensionality of hyperspectral data is usually very large, NMF tends to suffer from large computational complexity for the popular multiplicative iteration rule;(2) NMF is sensitive to noise(outliers), and thus the corrupted data will make the results of NMF meaningless. Although principal component analysis(PCA) can be used to mitigate these two problems, the transformed data will contain negative numbers, hindering the direct use of the multiplicative iteration rule of NMF. In this paper, we analyze the impact of PCA on NMF, and find that multiplicative NMF can also be applicable to data after principal component transformation. Based on this conclusion, we present a method to perform NMF in the principal component space, named ‘principal component NMF'(PCNMF). Experimental results show that PCNMF is both accurate and time-saving.

关键词： Non-negative matrix factorization(NMF) Principal component analysis(PCA) Endmember Hyperspectral

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A Dynamic Protocol Stack Structure for Diversified QoS Requirements in Ad Hoc Network

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China Communications 2016年第S1期13卷 43-53页

作者： DONG Fang Li Ou RAN Xiaomin JIN Feicai National Digital Switching system Engineering & Technological research Center Zhongxing Telecommunication Equipment corporation

A dynamic protocol stack(DPS) for ad hoc networks, together with a protocol stack construction scheme that is modeled as a multiconstrained knapsack problem is proposed. Compared to the traditional static protocol stack, DPS operates in a dynamic and adaptive manner and is scalable to network condition changes. In addition, a protocol construction algorithm is proposed to dynamically construct of the protocol stack each network node. Simulation results show that, the processing and forwarding performance of our scheme is close to 1 Gb/s, and the performance of our algorithm is close to that of the classical algorithms with much lower complexity.

关键词： ad hoc network QoS guarantee dynamic protocol stack protocol construction algorithm

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Numerical study on 3D effect and practical design in shield tunneling

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Underground Space 2019年第3期4卷 201-209页

作者： Hossain Md.Shahin Teruo Nakai Tetsuo Okuno Islamic University of Technology GazipurBangladesh geo-research Institute Japan Nagoya Institute of Technology NagoyaJapan Shimizu corporation TokyoJapan

In practice,different design methods are used in solving geotechnical problems depending on the type of issue such as the tunneling,braced excavation,or bearing capacity of a foundation,that is,the basic mechanism of the design method differs depending on the problems even for the same ground.A numerical analysis using the finite element method has recently become familiar owing to an improved computing performance;however,it is not widely used in the design of geotechnical problems including tunnel excavation owing to the reliability of the constitutive model of the ground *** a constitutive model of soils can properly express the properties of the ground material,a numerical analysis will play a vital role in solving the geotechnical *** this paper,the current state of a numerical analysis and its applicability in tunnel design are ***,the simulation of the ground behavior during tunnel excavation is carried out using sandy and clay ground parameters for shallow and deep tunnel *** paper is mainly focused on the effects of tunnel excavation under three-dimensional(3D)conditions,as well as the current design ***-linear 2D and 3D finite element analyses have been conducted,in which the elastoplastic sub-loading tij model has been used as a constitutive model of the *** performance and acceptability of the constitutive model have already been proven to reproduce the results of various model tests on different geotechnical problems such as the tunneling,braced excavation,and bearing capacity of a foundation,as well as the measured field *** was found that a 2D finite element analysis where the rate of stress release is considered,can be used for the prediction of the ground deformation and surface settlement;however,it does not provide rational information in the prediction of tunnel lining forces such as the stress,bending moment,and axial force,which emphasize the necessity of a 3D analysis with a proper cons

关键词： Shield tunneling Finite element analysis 3D effect

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Ozone Profile Retrieval from Satellite Observation Using High Spectral Resolution Infrared Sounding Instrument

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Advances in Atmospheric Sciences 2001年第5期18卷 959-971页

作者： Yanni Qu, Mitchell D. Goldberg and Murty Divakarla research and Data system corporation, 7833 Walker Dr Greenbelt. MD 20770 National Eivironment Satellite Data and Information Service, Office of research and Application, World Weather Building. 5200 Auth research and Data system corporation Greenbelt USA National Environment Satellite Data and Information Service Office of Research and Application Camp Springs USA

This paper presents a preliminary result on the retrieval of atmospheric ozone profiles using an im- proved regression technique and utilizing the data from the Atmospheric InfraRed Sounder (AIRS), a hyper-spectral Instrument expected to be flown on the EOS-AQUA platform in 20D2. Simulated AIRS spectra were used to study the sensitivity of AIRS radiance on the tropospheric and stratospheric ozone changes, and to study the impact of various channel combinations on the ozone profile retrieval. Sensitivity study results indicate that the AIRS high resolution spectral channels between the wavenumber 650- 800 cm-1 provide very useful information to accurately retrieve tropospheric and stratospheric ozone pro- files Eigenvector decomposition of AIRS spectra indicate that no more than 100 eigenvectors are needed to retrieve very accurate ozone profiles. The accuracy of the retrieved atmospheric ozone profile from the pres- ent technique and utilizing the AIRS data was compared with the accuracy obtained from current Advanced TIROS Operational Vertical Sounder (ATOVS) data aboard National Oceanic and Atmospheric Admini- stration (NOAA) satellites As expected, a comparison of retrieval results confirms that the ozone profile re- trieved with the AIRS data is superior to that of ATOVS

关键词： AIRS ATOVS Regression Eigenvector Principal component

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A voltage-mode DC–DC buck converter with fast output voltage-tracking speed and wide output voltage range

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Journal of Semiconductors 2014年第5期35卷 93-97页

作者：杨淼张白雪曹允孙锋锋孙伟锋 The 55th research Institute of China Electronic Technology Group corporation National ASIC System Engineering Research Center Southeast University

A high switching frequency voltage-mode buck converter with fast voltage-tracking speed and wide output voltage range has been proposed. A novel error amplifier （EA） is presented to achieve a high DC gain and get high phase margin, including a resistor and capacitor net, a unit gain block and a high gain block. The investigated converter has been fabricated with GF 0.35 μm CMOS process and can operate at 6 MHz with the output voltage range from 0.6 to 3.4 V. The experimental results show that the voltage-tracking speed can achieve 8.8 μs/V for up-tracking and 6 μs/V for down-tracking. Besides, the recovery time is less than 8 μs while the load current suddenly changes 400 mA.

关键词： DC-DC buck converter voltage-mode voltage-tracking speed

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Anomalous Channel Length Dependence of Hot-Carrier-Induced Saturation Drain Current Degradation in n-Type MOSFETs

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Chinese Physics Letters 2015年第8期32卷 193-195页

作者：张春伟刘斯扬孙伟锋周雷雷张艺苏巍张爱军刘玉伟胡久利何骁伟 National ASIC system Engineering Technology research Center Southeast University Nanjing 210096 CSMC Technologies corporation Wuxi 214028

The dependencies of hot-carrier-induced degradations on the effective channel length Lch,eff are investigated for n-type metal-oxide-semiconductor field effect transistor （MOSFETs）. Our experiments find that, with decreasing Lch,eff, the saturation drain current （Iasat ） degradation is unexpectedly alleviated. The further study demonstrates that the anomalous Lch,eff dependence of Idsat degradation is induced by the increasing influence of the substrate current degradation on the lazar degradation with Lch,eff reducing.

关键词： Anomalous Channel Length Dependence of Hot-Carrier-Induced Saturation Drain Current Degradation in n-Type MOSFETs

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Robust design and analysis of a conformal expansion nozzle with inverse-design idea

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Chinese Journal of Aeronautics 2018年第1期31卷 79-88页

作者： Wenbiao GAN Xiaocui ZHANG Tielin MA Qinling ZHANG Wu YUAN research Institute of Unmanned system Beihang University The First Aircraft Institute Aviation Industry Corporation of China Computer Network Information Center Chinese Academy of Sciences

This paper examines robust optimization design and analysis of a conformal expansion nozzle of flying wing Unmanned Aerial Vehicle （UAV） with the inverse-design idea. In view of flow features and stealth constraints, the inverse-design idea is described and the uncertainty-based robust design model is presented. A robust design system employs this model to combine deterministic optimization and robust optimization and is applied into design of a conformal expansion nozzle. The results indicate that design optimization can conform to the anticipation of the inversedesign idea and significantly improve the aerodynamic performance that meet the requirement of 6σ. The present method is a feasible nozzle design strategy that integrates robust optimization and inverse-design.

关键词： Aerodynamic analysis Inverse-design Nozzle Off-design Robust optimization

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Admission Control of VL in AFDX Under HRT Constraints

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Chinese Journal of Aeronautics 2011年第2期24卷 195-201页

作者： ZHOU Qiang QU Zhenliang LIN Hengqing School of Electronics and Information Engineering Beihang University Beijing 100191 China system Engineering research Institute China State Shipbuilding Corporation Beijing 100036 China

Avionics full duplex switched ethernet（AFDX） is a switched interconnection technology developed to provide reliable data exchange with strong data transmission time guarantees in internal communication of the spacecraft or *** link（VL） is an important concept of AFDX to meet quality of service（QoS） requirements in terms of end-to-end message deadlines.A VL admission control algorithm in AFDX network under hard real-time（HRT） constraints is *** on the scheduling prin-ciple of AFDX protocol,a packet scheduling scheme under HRT constraints is proposed,and after that an efficient VL admission control algorithm is *** proof that the algorithm can effectively determine whether VL should be admitted is *** simulative examples are presented to promote the conclusion.

关键词： avionics avionics full duplex switched ethernet virtual link switch hard real-time admission control

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