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Combined Novel Gate Level Model and Critical Primary Input Sharing for Genetic Algorithm Based Maximum Power Supply Noise Estimation
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作者 田志新 刘勇攀 杨华中 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第9期1375-1380,共6页
A gate level maximum power supply noise (PSN) model is defined that captures both IR drop and di/dt noise effects. Experimental results show that this model improves PSN estimation by 5.3% on average and reduces com... A gate level maximum power supply noise (PSN) model is defined that captures both IR drop and di/dt noise effects. Experimental results show that this model improves PSN estimation by 5.3% on average and reduces computation time by 10.7% compared with previous methods. Furthermore,a primary input critical factor model that captures the extent of primary inputs' PSN contribution is formulated. Based on these models,a novel niche genetic algorithm is proposed to estimate PSN more effectively. Compared with general genetic algorithms, this novel method can achieve up to 19.0% improvement on PSN estimation with a much higher convergence speed. 展开更多
关键词 power supply noise gate level model niche genetic algorithm
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Impacts of the Lowest Model Level Height on Tropical Cyclone Intensity and Structure 被引量:3
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作者 MA Zhanhong FEI Jianfang +1 位作者 HUANG Xiaogang CHENG Xiaoping 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2014年第2期421-434,共14页
Variable thicknesses in the lowest half-ηmodel level (LML) are often used in atmospheric models to compute surface diagnostic fields such as surface latent and sensible heat fluxes.The effects of the LML on simulat... Variable thicknesses in the lowest half-ηmodel level (LML) are often used in atmospheric models to compute surface diagnostic fields such as surface latent and sensible heat fluxes.The effects of the LML on simulated tropical cyclone (TC)evolution were investigated in this study using the Weather Research and Forecasting (WRF) model.The results demonstrated notable influences of the LML on TC evolution when the LML was placed below 12 m.The TC intensification rate decreased progressively with a lowering of the LML,but its ultimate intensity change was relatively small.The maximum 10-m winds showed different behavior to minimum sea level pressure and azimuthally-averaged tangential winds,and thus the windpressure relationship was changed accordingly by varying the LML.The TC circulation was more contracted in association with a higher LML.Surface latent heat fluxes were enhanced greatly by elevating the LML,wherein the wind speed at the LML played a dominant role.The changes in the wind speed at the LML were dependent not only on their profile differences,but also the different heights they were taken from.Due to the enhanced surface heat fluxes,more intense latent heat release occurred in the eyewall,which boosted the storm's intensification.A higher LML tended to produce a stronger storm,and therefore the surface friction was reinforced,which in turn induced stronger boundary layer inflow together with increased diabatic heating. 展开更多
关键词 tropical cyclone lowest model level simulation
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A simulation of winter wheat crop responses to irrigation management using CERES-Wheat model in the North China Plain 被引量:2
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作者 ZHOU Li-li LIAO Shu-hua +8 位作者 WANG Zhi-min WANG Pu ZHANG Ying-hua YAN Hai-jun GAO Zhen SHEN Si LIANG Xiao-gui WANG Jia-hui ZHOU Shun-li 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2018年第5期1181-1193,共13页
To improve efficiency in the use of water resources in water-limited environments such as the North China Plain(NCP), where winter wheat is a major and groundwater-consuming crop, the application of water-saving irr... To improve efficiency in the use of water resources in water-limited environments such as the North China Plain(NCP), where winter wheat is a major and groundwater-consuming crop, the application of water-saving irrigation strategies must be considered as a method for the sustainable development of water resources. The initial objective of this study was to evaluate and validate the ability of the CERES-Wheat model simulation to predict the winter wheat grain yield, biomass yield and water use efficiency(WUE) responses to different irrigation management methods in the NCP. The results from evaluation and validation analyses were compared to observed data from 8 field experiments, and the results indicated that the model can accurately predict these parameters. The modified CERES-Wheat model was then used to simulate the development and growth of winter wheat under different irrigation treatments ranging from rainfed to four irrigation applications(full irrigation) using historical weather data from crop seasons over 33 years(1981–2014). The data were classified into three types according to seasonal precipitation: 〈100 mm, 100–140 mm, and 〉140 mm. Our results showed that the grain and biomass yield, harvest index(HI) and WUE responses to irrigation management were influenced by precipitation among years, whereby yield increased with higher precipitation. Scenario simulation analysis also showed that two irrigation applications of 75 mm each at the jointing stage and anthesis stage(T3) resulted in the highest grain yield and WUE among the irrigation treatments. Meanwhile, productivity in this treatment remained stable through different precipitation levels among years. One irrigation at the jointing stage(T1) improved grain yield compared to the rainfed treatment and resulted in yield values near those of T3, especially when precipitation was higher. These results indicate that T3 is the most suitable irrigation strategy under variable precipitation regimes for stable yield of winter wheat with maximum water savings in the NCP. The application of one irrigation at the jointing stage may also serve as an alternative irrigation strategy for further reducing irrigation for sustainable water resources management in this area. 展开更多
关键词 crop simulation modeling deficit irrigation precipitation level CERES-Wheat model winter wheat North China Plain
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Parsimonious Model for Blood Glucose Level Monitoring in Type 2 Diabetes patients 被引量:2
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作者 ZHAO Fang MA Yan Fen +3 位作者 WEN Jing Xiao DU Yan Fang LI Chun Lin LI Guang Wei 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2014年第7期559-563,共5页
To establish the parsimonious model for blood glucose monitoring in patients with type 2 diabetes receiving oral hypoglycemic agent treatment. One hundred and fifty-nine adult Chinese type 2 diabetes patients were ran... To establish the parsimonious model for blood glucose monitoring in patients with type 2 diabetes receiving oral hypoglycemic agent treatment. One hundred and fifty-nine adult Chinese type 2 diabetes patients were randomized to receive rapid-acting or sustained-release gliclazide therapy for 12 weeks. 展开更多
关键词 SMBG HBALC Parsimonious model for Blood Glucose Level Monitoring in Type 2 Diabetes patients
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The Application of a Grey Markov Model to Forecasting Annual Maximum Water Levels at Hydrological Stations 被引量:12
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作者 DONG Sheng CHI Kun +1 位作者 ZHANG Qiyi ZHANG Xiangdong 《Journal of Ocean University of China》 SCIE CAS 2012年第1期13-17,共5页
Compared with traditional real-time forecasting,this paper proposes a Grey Markov Model(GMM) to forecast the maximum water levels at hydrological stations in the estuary area.The GMM combines the Grey System and Marko... Compared with traditional real-time forecasting,this paper proposes a Grey Markov Model(GMM) to forecast the maximum water levels at hydrological stations in the estuary area.The GMM combines the Grey System and Markov theory into a higher precision model.The GMM takes advantage of the Grey System to predict the trend values and uses the Markov theory to forecast fluctuation values,and thus gives forecast results involving two aspects of information.The procedure for forecasting annul maximum water levels with the GMM contains five main steps:1) establish the GM(1,1) model based on the data series;2) estimate the trend values;3) establish a Markov Model based on relative error series;4) modify the relative errors caused in step 2,and then obtain the relative errors of the second order estimation;5) compare the results with measured data and estimate the accuracy.The historical water level records(from 1960 to 1992) at Yuqiao Hydrological Station in the estuary area of the Haihe River near Tianjin,China are utilized to calibrate and verify the proposed model according to the above steps.Every 25 years' data are regarded as a hydro-sequence.Eight groups of simulated results show reasonable agreement between the predicted values and the measured data.The GMM is also applied to the 10 other hydrological stations in the same estuary.The forecast results for all of the hydrological stations are good or acceptable.The feasibility and effectiveness of this new forecasting model have been proved in this paper. 展开更多
关键词 Grey Markov model forecasting estuary disaster prevention maximum water level
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Water level updating model for flow calculation of river networks
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作者 Xiao-ling WU Xiao-hua XIANG +1 位作者 Li LI Chuan-hai WANG 《Water Science and Engineering》 EI CAS CSCD 2014年第1期60-69,共10页
Complex water movement and insufficient observation stations are the unfavorable factors in improving the accuracy of flow calculation of river networks. A water level updating model for river networks was set up base... Complex water movement and insufficient observation stations are the unfavorable factors in improving the accuracy of flow calculation of river networks. A water level updating model for river networks was set up based on a three-step method at key nodes, and model correction values were collected from gauge stations. To improve the accuracy of water level and discharge forecasts for the entire network, the discrete coefficients of the Saint-Venant equations for river sections were regarded as the media carrying the correction values from observation locations to other cross-sections of the river network system. To examine the applicability, the updating model was applied to flow calculation of an ideal river network and the Chengtong section of the Yangtze River. Comparison of the forecast results with the observed data demonstrates that this updating model can improve the forecast accuracy in both ideal and real river networks. 展开更多
关键词 plain river network cyclic looped channel network water level updating model hydrodynamic model error correction
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Verilog HDL modeling and design of 10Gb/s SerDes full rate CDR in 65nm CMOS
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作者 陈莹梅 Chen Xuehui +1 位作者 Yi Lvfan Wen Guanguo 《High Technology Letters》 EI CAS 2014年第2期140-145,共6页
Phase locked loop(PLL) is a typical analog-digital mixed signal circuit and a method of conducting a top level system verification including PLL with standard digital simulator becomes especially significant.The behav... Phase locked loop(PLL) is a typical analog-digital mixed signal circuit and a method of conducting a top level system verification including PLL with standard digital simulator becomes especially significant.The behavioral level model(BLM) of the PLL in Verilog-HDL for pure digital simulator is innovated in this paper,and the design of PLL based clock and data recovery(CDR)circuit aided with jitter attenuation PLL for SerDes application is also presented.The CDR employs a dual-loop architecture where a frequency-locked loop acts as an acquisition aid to the phase-locked loop.To simultaneously meet jitter tolerance and jitter transfer specifications defined in G.8251 of optical transport network(ITU-T OTN),an additional jitter attenuation PLL is used.Simulation results show that the peak-to-peak jitter of the recovered clock and data is 5.17 ps and 2.3ps respectively.The core of the whole chip consumes 72 mA current from a 1.0V supply. 展开更多
关键词 VERILOG-HDL behavioral level model BLM) phase locked loops PLL) clock and data recovery (CDR)
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Development and Theoretic Validation of Model of Drum Level Sloshing
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作者 曹小玲 刘孝锋 苏明 《Journal of Shanghai Jiaotong university(Science)》 EI 2007年第1期85-90,95,共7页
In order to develop a feasible model of drum level sloshing, the mechanism of drum level sloshing was analyzed, and the model of drum level sloshing was developed on the Easy5 software flat. The thermodynamic property... In order to develop a feasible model of drum level sloshing, the mechanism of drum level sloshing was analyzed, and the model of drum level sloshing was developed on the Easy5 software flat. The thermodynamic property of the model was validated by using the reference model, which was set up by using the method of lump parameter. The results indicate that the model can precisely reflect the phenomena of thermodynamic property inside drum, and the numeric error is within 1%. And the hydraulic property of the model was validated by the analytical theory of liquid sloshing, and the results indicate that the hydraulic property inside drum can also be correctly reflected by the model, and the sloshing period error is within 5%. The important work was done for exploring modeling for drum level sloshing, research of drum level sloshing and precision controlling of drum level. 展开更多
关键词 modularization modeling model of drum level sloshing combined cycle BOILER false level
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REVIEW OF HIGH LEVEL FAULT MODELING APPROACHES FOR MIXED-SIGNAL SYSTEMS
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作者 Xia Likun Ian Bell Antony Wilkinson 《Journal of Electronics(China)》 2010年第4期490-497,共8页
In the modern analogue design, Transistor Level Fault Simulation (TLFS) plays the im-portant part since every fault in the whole circuit has to be simulated at that level. Unfortunately, it is a very CPU intensive tas... In the modern analogue design, Transistor Level Fault Simulation (TLFS) plays the im-portant part since every fault in the whole circuit has to be simulated at that level. Unfortunately, it is a very CPU intensive task even though it maintains the high accuracy. Therefore, High Level Fault Modeling (HLFM) and High Level Fault Simulation (HLFS) are required in order to alleviate the efforts of simulation. In this paper, different HLFM approaches are reviewed at the device level during last two decades. We clarify their domains of application and evaluate their strengths and current limitations. We also analyze causes of faults and introduce various test approaches. 展开更多
关键词 High Level Fault modeling (HLFM) Automated model Generation (AMG)
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A leveling mechanism for the platform based on booms-constraint control of aerial vehicle
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作者 张翠红 Cao Xuepeng +3 位作者 Jiao Shengjie Yang Bin Wang Guanhong Zhou Zhaoqiang 《High Technology Letters》 EI CAS 2017年第3期322-329,共8页
In order to achieve an automatic leveling function for work platforms of aerial vehicles with mixed-booms( MAV) in full elevating domain,an auto-leveling mechanism for the platform is proposed based on a control metho... In order to achieve an automatic leveling function for work platforms of aerial vehicles with mixed-booms( MAV) in full elevating domain,an auto-leveling mechanism for the platform is proposed based on a control method of booms-constraint,where mixed-boom structures and elevating characteristics are considered. Three models of constraint strategies include non-constraint model,elevating constraint model and lowering constraint model,which is designed to meet the leveling requirements in full working extent. Through the hydro-mechatronic unified modeling,a virtual prototype model is set up based on the auto-leveling mechanism,and leveling performances of the platform are studied during booms elevating to the maximum working height and extent. Simulation results show that the control method of booms-constraint can realize auto-leveling of the platform under two typical working conditions,meanwhile a leveling deviation appears at the constrained point,but the platform inclination is adjusted in the permissible range. The control method does not only restrict booms' freedom elevating to a certain extent,but also impacts the booms extending to the maximum working range. Experimental results verify that the auto-leveling mechanism based on booms-constraint control is valid and rational,which provides an effective technology approach for development of the platform leveling of MAV. 展开更多
关键词 mixed-booms aerial vehicle(MAV) platform leveling booms-constraint control model simulating
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Quantum Spin Liquid Phase in the Shastry–Sutherland Model Detected by an Improved Level Spectroscopic Method
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作者 Ling Wang Yalei Zhang Anders W.Sandvik 《Chinese Physics Letters》 SCIE EI CAS CSCD 2022年第7期105-116,共12页
We study the spin-1/2 two-dimensional Shastry–Sutherland spin model by exact diagonalization of clusters with periodic boundary conditions, developing an improved level spectroscopic technique using energy gaps betwe... We study the spin-1/2 two-dimensional Shastry–Sutherland spin model by exact diagonalization of clusters with periodic boundary conditions, developing an improved level spectroscopic technique using energy gaps between states with different quantum numbers. The crossing points of some of the relative(composite) gaps have much weaker finite-size drifts than the normally used gaps defined only with respect to the ground state, thus allowing precise determination of quantum critical points even with small clusters. Our results support the picture of a spin liquid phase intervening between the well-known plaquette-singlet and antiferromagnetic ground states, with phase boundaries in almost perfect agreement with a recent density matrix renormalization group study, where much larger cylindrical lattices were used [J. Yang et al., Phys. Rev. B 105, L060409(2022)]. The method of using composite low-energy gaps to reduce scaling corrections has potentially broad applications in numerical studies of quantum critical phenomena. 展开更多
关键词 red SSM Sutherland model Detected by an Improved Level Spectroscopic Method Quantum Spin Liquid Phase in the Shastry model
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Liver Segmentation in CT Images Based on DRLSE Model
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作者 黄永锋 齐萌 严加勇 《Journal of Donghua University(English Edition)》 EI CAS 2012年第6期493-496,共4页
Liver segmentation in CT images is an important step for liver volumetry and vascular evaluation in liver pre-surgical planning. In this paper, a segmentation method based on distance regularized level set evolution(D... Liver segmentation in CT images is an important step for liver volumetry and vascular evaluation in liver pre-surgical planning. In this paper, a segmentation method based on distance regularized level set evolution(DRLSE) model was proposed, which incorporated a distance regularization term into the conventional Chan-Vese (C-V) model. In addition, the region growing method was utilized to generate the initial liver mask for each slice, which could decrease the computation time for level-set propagation. The experimental results show that the method can dramatically decrease the evolving time and keep the accuracy of segmentation. The new method is averagely 15 times faster than the method based on conventional C-V model in segmenting a slice. 展开更多
关键词 liver segmentation distance regularized level set evolution (DRLSE) model Chan-Vese (C-V) model region growing
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Numerical modelling of the sea level under the actions of the tide and strong wind in the Bohai Sea
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作者 Zhang Yanting and Wang Yijiao First Institute of Oceanography, SOA, Qingdao, China 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1989年第4期511-520,共10页
In this paper, the numerical modelling of the tidal level and current in the Bohai Sea was carried out with ADI method, by taking the sum of four main tidal components M2,S2K2,O1 as the open boundary condition. The ca... In this paper, the numerical modelling of the tidal level and current in the Bohai Sea was carried out with ADI method, by taking the sum of four main tidal components M2,S2K2,O1 as the open boundary condition. The calculated values were consistent with the predicted ones (the observed values in the case of calm) in the Tidal Table. On the basis of the modelling of the tide, the sea level and current fields under the effects of strong wind were simulated. The calculated results were also quite satisfactory. 展开更多
关键词 HIGH Numerical modelling of the sea level under the actions of the tide and strong wind in the Bohai Sea
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Transient study of droplet oscillation characteristics driven by an electric field
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作者 高燕飞 何纬峰 +6 位作者 Adam Abdalazeem 施其乐 张继荣 苏鹏飞 俞思涌 姚照辉 韩东 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第12期609-617,共9页
Electrowetting technology,a microfluidic technology,has attracted more and more attention in recent years and has broad prospects in terms of microdroplet drive.In this paper,the dynamic contact angle theory is used t... Electrowetting technology,a microfluidic technology,has attracted more and more attention in recent years and has broad prospects in terms of microdroplet drive.In this paper,the dynamic contact angle theory is used to develop a numerical model to predict the droplet dynamic contact behavior and internal flow field under electrowetting.In particular,based on the established computational model of droplet force balance,the dynamic process of a droplet under electrowetting is analyzed,including the perspective of pressure variation and force balance inside the droplet.The results show that when the alternating current frequency increases from 50 Hz to 500 Hz,the amplitude of the oscillation waveform after droplet stabilization is 0.036 mm,0.016 mm,0.013 mm and 0.002 mm,while the relevant droplet oscillation period T is 11 ms,4 ms,2 ms and 1 ms,respectively.It is also found that the initial phase angle does not affect the droplet oscillation amplitude.In addition,the pressure on the droplet surface under alternating current electrowetting increases rapidly to the maximum value with resonant waveform oscillation,and the droplet will present different resonance modes under voltage stimulation.The higher the resonance mode is,the smaller the droplet oscillation amplitude is and the streamline at the interface will present an eddy current,in which the number of vortices matches the resonance mode.A high resonance mode corresponds to a small droplet amplitude,while there are more vortices with a smaller size. 展开更多
关键词 ELECTROWETTING dynamic contact angle level set model droplet oscillation
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Research and exploration progress on lithium deposits in China 被引量:12
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作者 Deng-hong Wang Hong-zhang Dai +6 位作者 Shan-bao Liu Cheng-hui Wang Yang Yu Jing-jing Dai Li-jun Liu Yue-qing Yang Sheng-chao Ma 《China Geology》 2020年第1期137-152,共16页
Since 2012,some advances have been made through the resource investigation,metallogenesis research,and comprehensive utilizing of lithium deposits in China.Firstly,the progress of lithium exploration has been made in ... Since 2012,some advances have been made through the resource investigation,metallogenesis research,and comprehensive utilizing of lithium deposits in China.Firstly,the progress of lithium exploration has been made in Sichuan,Xinjiang,Qinghai and Jiangxi provinces(autonomous region).Li deposits are not only found within the pegmatite rocks but also within the granitic rocks and sedimentary rocks.Secondly,the methods of geological survey,geochemical and geophysical exploration,remote sensing technology and even drilling technology have been improved,which can be delineating orebodies quickly.Thirdly,the mechanisms of Li mineralization were summarized by analyzing the relationship between the Li contents and kinds of geological phenomena.Based on practice,a new understanding of"multi-cycle,deep circulation,integration of internal and external"metallogenic mechanism or"MDIE"metallogenic mechanism for short has been put forwarded further in this paper,and the"five levels+basement"exploration model has been successfully expanded to guide the prospecting work both in the Jiajika and Keeryin pegmatite ore fields in western Sichuan Province.Besides,new progress has been made in the aspect of amblygonite deposits of granite-type and hydrothermal type in the Mufushan-Jiuling ore district,which points out a new direction for prospecting new types of lithium deposits in China. 展开更多
关键词 Lithium deposits Amblygonite "MDIE"metallogenic mechanism "Five levels+basement"exploration model Mineral exploration engineering China
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Evaluation of the geopotential value W_0^(LVD) of China 被引量:1
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作者 Lin He Yonghai Chu Nan Yu 《Geodesy and Geodynamics》 2017年第6期408-412,共5页
Estimation of the zero-height geopotential value W_0^(LVD) for the CVD(China Vertical Datum) plays a fundamental role in the connection of traditional height reference systems into a global height system.Estimatio... Estimation of the zero-height geopotential value W_0^(LVD) for the CVD(China Vertical Datum) plays a fundamental role in the connection of traditional height reference systems into a global height system.Estimation the W_0^(LVD) of China is based on the computation of the mean geopotential offset between the value W_0= 62636856.0 m^2 s^(-2), selected as reference in this study, and the unknown geopotential value W_0^(LVD). This estimation is based on the combination of ellipsoidal heights, levelled heights(referring to the CVD), and some physical parameters, such as geopotential values, gravity values, and geoid undulations.The geoid undulations derived from the GGM(Global Geopotential Models). This combination is performed through three approaches: The first one is based on the theory of Molodensky, and the second one compares levelled heights and geopotential values derived from the GGMs, while the third one analyses the differences between GPS/Levelling and GGMs geoid undulations. The approaches are evaluated at 65 benchmarks(BMs) covered around Qingdao where the tide gauge is used to observe the local mean sea level of China. The results from three approaches are very similar. Furthermore, the W_0^(LVD)determined for the China local vertical datum was 62636852.9462 m^2 s^(-2), indicates a bias of about3.0538 m^2/s^(-2) compared to the conventional value of 62636856.0 m^2 s^(-2). 展开更多
关键词 Global geopotential models GPS/Levelling BMs hina vertical datum Local vertical datum Zero-height geopotential
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Dynamic simulation of drum level sloshing of heat recovery steam generator
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作者 曹小玲 皮正仁 +2 位作者 蒋绍坚 杨卫宏 B.Wlodzimerz 《Journal of Central South University》 SCIE EI CAS 2013年第2期413-423,共11页
Drum level sloshing is the latest discovery in the application of heat recovery steam generator (HRSG) in combined cycle, and shows certain negative influence on drum level controlling. In order to improve drum level ... Drum level sloshing is the latest discovery in the application of heat recovery steam generator (HRSG) in combined cycle, and shows certain negative influence on drum level controlling. In order to improve drum level controlling, influence factors on the drum level sloshing were investigated. Firstly, drum sub-modules were developed using the method of modularization modeling, and then the model of drum level sloshing was set up as well. Experiments were carried out on the experimental rig, and the model was validated using the obtained experimental results. Dynamic simulation was made based on the model to get a 3-D graph of drum level sloshing, which shows a vivid procedure of drum level sloshing. The effect of feed-water flow rate, main-steam flow rate and heating quantity on the drum level sloshing was analyzed. The simulation results indicate that the signals with frequency higher than 0.05 Hz are that of drum level sloshing, the signals with frequency of 0.0-0.05 Hz are that of drum level trendy and "false water level", and variation of the feed-water flow rates, main-steam flow rates and heating quantities can change the frequency of drum level sloshing, i.e., the frequency of sloshing increases with the increase of feed-water flow rate, or the decrease of the main-steam flow rate and the heating quantity. This research work is fundamental to improve signal-to-noise ratio of drum level signal and precise controlling of drum level. 展开更多
关键词 combined cycle heat recovery steam generator false level drum level sloshing model modularization modeling
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Contour tracking using weighted structure tensor based variational level set
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作者 胡宏伟 马波 曹淑娟 《Journal of Beijing Institute of Technology》 EI CAS 2014年第2期218-225,共8页
A novel contour tracking method using weighted structure tensor based variational level set is proposed in this paper.The image is first converted to weighted structure tensor field by extracting apositive definite sy... A novel contour tracking method using weighted structure tensor based variational level set is proposed in this paper.The image is first converted to weighted structure tensor field by extracting apositive definite symmetric covariance matrix for each pixel.Then,a level set method is employed to represent object contour implicitly which separates the image domain into two areas each modeled by tensor field based Gaussian mixture model separately.By solving agradient flow equation of energy functional with respect to the level set,the object contour will converge to its real profile in the newly arrived frame.Experimental results on several video sequences demonstrate the better performance of our method than the other two contour tracking algorithms. 展开更多
关键词 contour tracking weighted structure tensor Gaussian mixture model level set
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A new online modelling method for aircraft engine state space model 被引量:1
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作者 Shuwei PANG Qiuhong LI Haibo ZHANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2020年第6期1756-1773,共18页
To overcome the drawbacks of current modelling method for aircraft engine state space model,a new method is introduced.The form of state space model is derived by using Talyor series to expand the nonlinear model that... To overcome the drawbacks of current modelling method for aircraft engine state space model,a new method is introduced.The form of state space model is derived by using Talyor series to expand the nonlinear model that is implicit equations and involves many iterations.A partial derivative calculation method for iterations is developed to handle the influence of iterations on parameters.The derivative calculation and the aerothermodynamics calculations are combined in the component level model with fixed number Newton-Raphson(N-R)iterations.Mathematical derivation and simulations show the convergence ability of proposed method.Simulations show that comparing with the linear parameter varying model and centered difference based state space model,much higher accuracy of proposed online modelling method is achieved.The accuracy of the state space model built by proposed method can be maintained when the step amplitudes of inputs are within 2%,and the responses of the state space model can match those of the component level model when each input steps larger amplitudes.In addition,an online verification was carried out to show the capability of modelling at any operating point and that state space model can predict future outputs accurately.Thus,the effectiveness of the proposed method is demonstrated. 展开更多
关键词 Aircraft engines Component level model Online modelling Partial derivative State space models
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Prediction of the future flood severity in plain river network region based on numerical model: A case study 被引量:7
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作者 胡孜军 王玲玲 +1 位作者 唐洪武 戚晓明 《Journal of Hydrodynamics》 SCIE EI CSCD 2017年第4期586-595,共10页
Suzhou is one of China's most developed regions, located in the eastern part of the Yangtze Delta. Due to its location and river features, it may at a high risk of flood under the climate change background in the fut... Suzhou is one of China's most developed regions, located in the eastern part of the Yangtze Delta. Due to its location and river features, it may at a high risk of flood under the climate change background in the future. In order to investigate the flood response to the extreme scenario in this region, 1-D hydrodynamic model with real-time operations of sluices and pumps is established. The rain-runoff processes of the urban and rural areas are simulated by two lumped hydrologic models, respectively. Indicators for a quantitative assessment of the flood severity in this region are proposed. The results indicate that the existing flood control system could prevent the Suzhou Downtown from inundation in the future. The difficulty of draining the Taihu Lake floods should be given attention to avoid the flood hazard. The modelling approach based on the in-bank model and the evaluation parameters could be effective for the flood severity estimation in the plain river network catchment. The insights from this study of the possible future extreme flood events may assist the policy making and the flood control planning. 展开更多
关键词 Flood control hydrodynamic model sea level rise extreme rain Suzhou District
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