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Hyperbolic Tangent Support Vector Machine

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Journal of Donghua University(English Edition) 2010年第5期27卷 705-708页

作者：刘叶青刘三阳谷明涛 School of Science Xidian University School of Science Henan University of Science & Technology 96251 PLA troops

By utilizing hyperbolic tangent function,we constructed a novel hyperbolic tangent loss function to reduce the influences of outliers on support vector machine(SVM)classification *** new loss function not only limits the maximal loss value of outliers but also is *** tangent SVM(HTSVM)is then proposed based on the new loss *** experimental results show that HTSVM reduces the effects of outliers and gives better generalization performance than the classical SVM on both artificial data and UCI data ***,the proposed hyperbolic tangent loss function and HTSVM are both effective.

关键词： support vector machine(SVM) classification pattern recognition

A BDSPHERE Solar Radiation Pressure Model for BDS GEO Satellites

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A BDSPHERE Solar Radiation Pressure Model for BDS GEO Satell...

Flight Dynamic Analysis of Hypersonic Vehicle Considering Liquid-Solid Coupling

第十一届中国卫星导航年会

作者： Rui Guo Xiaojie Li Jie Xin Shan Wu Shuai Liu 32021 troops

The precision of BDS navigation message based on global satellite laser ranging(SLR) analysis is about 60 cm for geostationary earth orbit(GEO) *** is an obvious gap between the POD accur

关键词： BDS GEO SRP model Precise orbit determination Dynamic smoothing Fourier series

来源： cnki会议 cnki会议 cnki会议评论

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Transactions of Nanjing University of Aeronautics and Astronautics 2015年第1期32卷 81-88页

作者：徐晓东黄一敏蔡晓斌 College of Automation Engineering Nanjing University of Aeronautics and Astronautic Research Institute of UAV Nanjing University of Aeronautics and Astronautic 95835 PLA troops

With the liquid propellant making up 60%—70% of the takeoff weight of the hypersonic vehicle,the dynamic load caused by great propellant sloshing interacts with the flexible structure of the ***,the dynamic model displays characteristics of strong coupling with structure/control and *** on the sloshing mass dynamic simplified as a spring-mass-damping model,a rigid-flexible-sloshing model is ***,the effect on the dynamic performance of the coupled model is analyzed with changing frequency and *** results show that propellant sloshing dynamics significantly affects the rigid body motion modes,especially flexible mode and short *** right half plane pole(RHP)moves far from the imaginary axis with the consumption of the *** flexible mode attenuates with the increase of the sloshing damping,and the coupling becomes stronger when sloshing frequency is close to the short mode frequency or the flexible frequency of the beam.

关键词： hypersonic vehicles liquid propellant sloshing coupling model structure vibration

Simulation and analysis of node throughput using smart antenna in wireless mesh networks

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The Journal of China Universities of Posts and Telecommunications 2007年第2期14卷 28-32,50页

作者： ZHANG Yong WEI Yi-fei ZHANG Li-kun SONG Jun-de School of Electronic Engineedng Beijing University of Posts and Beijing 100876 China The Translation Department of the Second Artillery troops of PLA Beijing 100820 China

Smart antenna technology is introduced to wireless mesh networks. Smart antennas based wider-range access medium access control （MAC） protocol （SWAMP） is used as MAC protocol for IEEE 802.11 mesh networks in this study. The calculation method of node throughput in chain and arbitrary topology is proposed under nodes fairness guarantee. Network scale and interference among nodes are key factors that influence node throughput. Node distribution pattern near the gateway also affects the node throughput. Experiment based on network simulator-2 （NS-2） simulation platform compares node throughput between smart antenna scenario and omni-antenna scenario. As smart antenna technology reduces the bottle collision domain, node throughput increases observably.

关键词： wireless mesh networks throughput smart antenna

Preliminary Calibration of GPS Signals and Its Effects on Soil Moisture Estimation

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Acta meteorologica Sinica 2013年第2期27卷 221-232页

作者：万玮李黄陈秀万罗鹏万家欢 Institute of Remote Sensing and GIS Peking University Meteorological Observation Center of China Meteorological Administration 92292 troops PLA

In recent years, Global Navigation Satellite Systems Reflectometry （GNSS-R） is developed to estimate soil moisture content （SMC） as a new remote sensing tool. Signal error of Global Positioning System （GPS） bistatic radar is an important factor that affects the accuracy of SMC estimation. In this paper, two methods of GPS signal calibration involving both the direct and reflected signals are introduced, and a detailed explanation of the theoretical basis for such methods is given. An improved SMC estimation model utilizing calibrated GPS L-band signals is proposed, and the estimation accuracy is validated using the airborne GPS data from the Soil Moisture Experiment in 2002 （SMEX02）. We choose 21 sites with soybean and corn in the Walnut Creek region of the US for validation. The sites are divided into three categories according to their vegetation cover： bare soil, mid-vegetation cover （Mid-Veg）, and high-vegetation cover （High-Veg）. The accuracy of SMC estimation .is 11.17% for bare soil and 8.12% for Mid-Veg sites, much better than that of the traditional model. For High-Veg sites, the effect of signal attenuation due to vegetation cover is preliminarily taken into consideration and a linear model related to Normalized Difference Vegetation Indices （NDVI） is adopted to obtain a factor for rectifying the ＂over-calibration＂, and the error for High-Veg sites is finally reduced to 3.81%.

关键词： GNSS-R soil moisture signal calibration bistatic radar

The Interdecadal Changes of South Pacific Sea Surface Temperature in the Mid-1990s and Their Connections with ENSO

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Advances in Atmospheric Sciences 2014年第1期31卷 66-84页

作者： LI Gang LI Chongyin TAN Yanke BAI Tao Institute of Meteorology and Oceanography PLA University of Science and Technology LASG Institute of Atmospheric Physics Chinese Academy of Sciences No. 94162 troops of PLA

The characteristic changes of South Pacific sea surface temperature anomalies （SSTAs） for the period January 1979 to December 2011, during which the 1990s Pacific pan-decadal variability （PDV） interdecadal regime shifts occurred, were examined. Empirical Orthogonal Function （EOF） analysis was applied to the monthly mean SSTA for two sub-periods： January 1979 to December 1994 （P 1） and January 1996 to December 2011 （P2）. Both the spatial and temporal features of the leading EOF mode for P1 and P2 showed a remarkable difference. The spatial structure of the leading EOF changed from a tripolar pattern for P 1 （EOF-P 1） to a dipole-like pattern for P2 （EOF-P2）. Besides, EOF-P 1 （EOF-P2） had significant spectral peaks at 4.6 yr （2.7 yr）. EOF-P2 not only had a closer association with E1 Nifio-Southern Oscillation （ENSO）, but also showed a faster response to ENSO than EOF-P1 based on their lead-lag relationships with ENSO. During the development of ENSO, the South Pacific SSTA associated with ENSO for both PI and P2 showed a significant eastward propagation. However, after the peak of ENSO, EOF-P1 showed a stronger persistence than EOF-P2, which still showed eastward propagation. The variability of the SSTA associated with the whole process of ENSO evolution during P1 and the SSTA associated with the development of ENSO during P2 support the existence of ocean-to-atmosphere forcing, but the SSTA associated with the decay of ENSO shows the phenomenon of atmosphere-to-ocean forcing.

关键词： ENSO South Pacific abrupt change of climate air-sea interaction

Feedback Attitude Sliding Mode Regulation Control of Spacecraft Using Arm Motion

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Chinese Journal of Mechanical Engineering 2013年第5期26卷 873-880页

作者： SHI Ye LIANG Bin XU Dong WANG Xueqian XU Wenfu Qian Xuesen Laboratory of Space Technology Dongfanghong Development Ltd Shenzhen Beijing Military Command Area 66240 Troops Shenzhen Graduate School Harbin Institute of Technology

The problem of spacecraft attitude regulation based on the reaction of arm motion has attracted extensive attentions from both engineering and academic *** of the solutions of the manipulator’s motion tracking problem just achieve asymptotical stabilization performance,so that these controllers cannot realize precise attitude regulation because of the existence of non-holonomic ***,sliding mode control algorithms are adopted to stabilize the tracking error with zero transient *** to the switching effects of the variable structure controller,once the tracking error reaches the designed hyper-plane,it will be restricted to this plane permanently even with the existence of external ***,precise attitude regulation can be ***,taking the non-zero initial tracking errors and chattering phenomenon into consideration,saturation functions are used to replace sign functions to smooth the control *** relations between the upper bounds of tracking errors and the controller parameters are derived to reveal physical characteristic of the *** models of free-floating space manipulator are established and simulations are conducted in the *** results show that the spacecraft’s attitude can be regulated to the position as desired by using the proposed algorithm,the steady state error is 0.000 2 *** addition,the joint tracking trajectory is smooth,the joint tracking errors converges to zero quickly with a satisfactory continuous joint control *** proposed research provides a feasible solution for spacecraft attitude regulation by using arm motion,and improves the precision of the spacecraft attitude regulation.

关键词： attitude regulation space robot trajectory tracking sliding mode control

SS-SERA:An improved framework for architectural level soft error reliability analysis

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Journal of Central South University 2012年第11期19卷 3129-3146页

作者：成玉马安国王永文唐遇星张民选 School of Computer Science National University of Defense Technology People's Liberation Army troops 61741

Integrated with an improved architectural vulnerability factor （AVF） computing model, a new architectural level soft error reliability analysis framework, SS-SERA （soft error reliability analysis based on SimpleScalar）, was developed. SS-SERA was used to estimate the AVFs for various on-chip structures accurately. Experimental results show that the AVFs of issue queue （IQ）, register update units （RUU）, load store queue （LSQ） and functional unit （FU） are 38.11%, 22.17%, 23.05% and 24.43%, respectively. For address-based structures, i.e., levell data cache （LID）, DTLB, level2 unified cache （L2U）, levell instruction cache （LII） and ITLB, AVFs of their data arrays are 22.86%, 27.57%, 14.80%, 8.25% and 12.58%, lower than their tag arrays＇ AVFs which are 30.01%, 28.89%, 17.69%, 10.26% and 13.84%, respectively. Furthermore, using the AVF values obtained with SS-SERA, a qualitative and quantitative analysis of the AVF variation and predictability was performed for the structures studied. Experimental results show that the AVF exhibits significant variations across different structures and workloads, and is influenced by multiple microarchitectural metrics and their interactions. Besides, AVFs of SPEC2K floating point programs exhibit better predictability than SPEC2K integer programs.

关键词： soft error architectural vulnerability factor (AVF) AVF estimation model

Simplified Calculation of Flow Resistance of Suspension Bridge Main Cable Dehumidification System

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Fluid Dynamics & Materials Processing 2021年第6期17卷 1195-1211页

作者： Zhiyuan Tu Fusheng Peng Zijie Wei Guo Qian Jie Wang Chunjie Huang College of National Defense Engineering Army Engineering University of PLANanjing210007China 92318 troops Beijing100089China

To calculate the flow resistance of a main cable dehumidification system,this study considers the air flow in the main cable as the flow in a porous medium,and adopts the Hagen–Poiseuille equation by using average hydraulic radius and capillary bundle models.A mathematical derivation is combined with an experimental study to obtain a semi-empirical flow resistance ***,Fluent software is used to simulate the flow resistance across the main cable relative to the experimental *** on the actual measured results for a Yangtze River bridge,this study verifies the semi-empirical formula,and indicates that it can be applied in actual engineering.

关键词： Main cable dehumidification computational fluid dynamics dry air semi-empirical flow resistance formula