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statistical model-Based Face Pose Estimation

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Transactions of Tianjin University 2007年第2期13卷 152-156页

作者：戈新良杨杰李冯王华华 Institute of Image Processing and Pattern Recognition Shanghai Jiaotong University

A robust face pose estimation approach is proposed by using face shape statistical model approach and pose parameters are represented by trigonometric functions. The face shape statistical model is firstly built by analyzing the face shapes from different people under varying poses. The shape alignment is vital in the process of building the statistical model. Then, six trigonometric functions are employed to represent the face pose parameters. Lastly, the mapping function is constructed between face image and face pose by linearly relating different parameters. The proposed approach is able to estimate different face poses using a few face training samples. Experimental results are provided to demonstrate its efficiency and accuracy.

关键词： pose estimation face alignment statistical model face recognition

Macroscopic model and statistical model to characterize electromagnetic information of a digital coding metasurface

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National Science Review 2024年第3期11卷 159-171页

作者： Rui Wen Shao Jun Wei Wu Zheng Xing Wang Hui Xu Han Qing Yang Qiang Cheng Tie Jun Cui Institute of Electromagnetic Space Southeast University State Key Laboratory of Millimeter Waves Southeast University Peng Cheng Laboratory Pazhou Laboratory(Huangpu)

A digital coding metasurface is a platform connecting the digital space and electromagnetic wave space, and has therefore gained much attention due to its intriguing value in reshaping wireless channels and realizing new communication architectures. Correspondingly, there is an urgent need for electromagnetic information theory that reveals the upper limit of communication capacity and supports the accurate design of metasurface-based communication systems. To this end, we propose a macroscopic model and a statistical model of the digital coding metasurface. The macroscopic model uniformly accommodates both digital and electromagnetic aspects of the meta-atoms and predicts all possible scattered fields of the digital coding metasurface based on a small number of simulations or measurements. Full-wave simulations and experimental results show that the macroscopic model is feasible and accurate. A statistical model is further proposed to correlate the mutual coupling between meta-atoms with covariance and to calculate the entropy of the equivalent currents of digital coding metasurface. These two models can help reconfigurable intelligent surfaces achieve more accurate beamforming and channel estimation, and thus improve signal power and coverage. Moreover, the models will encourage the creation of a precoding codebook in metasurface-based direct digital modulation systems, with the aim of approaching the upper limit of channel capacity. With these two models, the concepts of current space and current entropy, as well as the analysis of information loss from the coding space to wave space, is established for the first time, helping to bridge the gap between the digital world and the physical world, and advancing developments of electromagnetic information theory and new-architecture wireless systems.

关键词： electromagnetic information theory current entropy current space digital coding metasurface macroscopic model statistical model

statistical model of the 3-D Braided Composites Strength

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Wuhan University Journal of Natural Sciences 2007年第6期12卷 1077-1082页

作者： XIAO Laiyuan ZUO Weiwei CAI Ganwei LIAO Daoxun School of Software Engineering Huazhong University ofScience and Technology Wuhan 430074 Hubei China

Based on the statistical model for the tensile statistical strength of unidirectional composite materials and the stress analysis of 3-D braided composites, a new method is proposed to calculate the tensile statistical strength of the 3-D braided compos- ites. With this method, the strength of 3-D braided composites can be calculated with very large accuracy, and the statistical parameters of 3-D braided composites can be determined. The numerical result shows that the tensile statistical strength of 3-D braided composites can be predicted using this method.

关键词： 3-D braided composites strength calculation statistical model

Large Signal statistical model Oriented Parameter Extraction Method for GaN High Electron Mobility Transistors

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Chinese Journal of Electronics 2017年第6期26卷 1319-1324页

作者： YU Xuming XU Yuehang WEN Zhang CHEN Zhikai HONG Wei State Key Laboratory of Millimeter Wave Southeast Univeristy School of Electronic Engineering University of Electronic Science and Technology of China

Efficient parameter extraction method is essential to establish large signal statistical model. This paper presents an automatic parameter extraction method of I-V model for Gallium nitride(GaN) High electron mobility transistors(HEMTs) large signal statistical model. To accurate modeling the statistical characterization, all of 53 parameters in an I-V model are considered. In order to realize automatic parameter extraction, the model parameters are divided into blocks according to their physical meaning to reduce the complexity of the I-V model. Different parameter blocks are extracted separately by fitting the pulsed I-V transfer characteristic curves of the device at different quiescent bias points. A large signal statistical model for 0.25μm GaN HEMTs process has been established by using the proposed method after measuring 34 GaN HEMTs from 10 batches. The results show that the large-signal performances(Output power and Power added efficiency) can be reproduced with high accuracy by the proposed statistical model.

关键词： statistical model Parameter extraction GaN HEMTs Large signal model

Using a skillful statistical model to predict September sea ice covering Arctic shipping routes

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Acta Oceanologica Sinica 2020年第5期39卷 11-25页

作者： Sha Li Muyin Wang Wenyu Huang Shiming Xu Bin Wang Yuqi Bai Ministry of Education Key Laboratory for Earth System modeling Department of Earth System ScienceTsinghua UniversityBeijing 100084China Joint Institute for the Study of the Atmosphere and Ocean University of WashingtonSeattle WA98195USA Pacific Marine Environmental Laboratory National Oceanic and Atmospheric AdministrationSeattle WA98115USA State Key Laboratory of Numerical modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

The rapid decrease in Arctic sea ice cover and thickness not only has a linkage with extreme weather in the midlatitudes but also brings more opportunities for Arctic shipping routes and polar resource exploration,both of which motivate us to further understand causes of sea-ice variations and to obtain more accurate estimates of seaice cover in the ***,a novel data-driven method,the causal effect networks algorithm,is applied to identify the direct precursors of September sea-ice extent covering the Northern Sea Route and Transpolar Sea Route at different lead times so that statistical models can be constructed for sea-ice *** whole study area was also divided into two parts:the northern region covered by multiyear ice and the southern region covered by seasonal *** forecast models of September sea-ice extent in the whole study area(TSIE)and southern region(SSIE)at lead times of 1–4 months can explain over 65%and 79%of the variances,respectively,but the forecast skill of sea-ice extent in the northern region(NSIE)is limited at a lead time of 1 *** lead times of 1–4 months,local sea-ice concentration and sea-ice thickness have a larger influence on September TSIE and SSIE than other teleconnection *** the lead time is more than 4 months,the surface meridional wind anomaly from northern Europe in the preceding autumn or early winter is dominant for September TSIE variations but is comparable to thermodynamic factors for NSIE and *** suggest that this study provides a complementary approach for predicting regional sea ice and is helpful in evaluating and improving climate models.

关键词： regional sea ice Arctic shipping routes machine learning statistical model predictions

Optimization Methodology of Empirical Electronic Theory by Employing statistical model

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Journal of Beijing Institute of Technology 2018年第3期27卷 426-432页

作者： Donghu Yang Qunbo Fan Fuchi Wang Lu Wang Tiejian Su School of Material Science and Engineering Beijing Institute of Technology

An optimization methodology of empirical electronic theory(EET)for solids and molecules has been developed by employing a statistical model in this *** current paper calculates the hybridization states of different atoms in some crystal structures and succeeds in predicting valence states of *** prediction ofγ-Fe hybridization states based on statistics is found to be in reasonable agreement with early *** calculating Cr alloy austenite and Cr alloy martensite,the statistical results proved stable for each atom,and it is found that the valence electron structure of an atom depends on its element type and location in the crystal cell;finally,wear resistant steel with1 wt% C is designed by using a statistical model which is consistent with traditional empirical design.

关键词： empirical electronic theory(EET) statistical model valence electron structure(VES) ma-terial design

Prediction and setup of phytoplankton statistical model of Qiandaohu Lake

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Journal of Zhejiang University Science 2004年第10期5卷 1206-1210页

作者：严力蛟全为民赵晓慧 AgroEcologyInstitute LifeScienceCollegeZhejiangUniversityHangzhou310029China EastChinaSeaFisheriesResearchInstitute ChineseAcademyo[FisheriesScienceShanghai200090China

This research considers the mathematical relationship between concentration of Chla and seven environmental factors, i.e. Lake water temperature (T), Secci-depth (SD), pH, DO, CODMn, Total Nitrogen (TN), Total Phosphorus (TP). Stepwise linear regression of 1997 to 1999 monitoring data at each sampling point of Qiandaohu Lake yielded the multivariate regression models presented in this paper. The concentration of Chla as simulation for the year 2000 by the regression model was similar to the observed value. The suggested mathematical relationship could be used to predict changes in the lakewater environment at any point in time. The results showed that SD, TP and pH were the most significant factors affecting Chla concentration.

关键词： Qiandaohu Lake Stepwise linear regression statistical model Chla

Parton distribution functions and nuclear EMC effect in a statistical model

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Chinese Physics C 2010年第9期34卷 1417-1420页

作者：邵立晶张运华马伯强 School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University

A new and simple statistical approach is performed to calculate the parton distribution functions （PDFs） of the nucleon in terms of light-front kinematic *** expressions of x-dependent PDFs are obtained in the whole x *** thereafter,we treat the temperature T as a parameter of the atomic number A to explain the nuclear EMC effect in the region x ∈ [0.2,0.7].We give the predictions of PDF ratios,and they are very different from those by other models,thus experiments aiming at measuring PDF ratios are suggested to provide a discrimination of different models.

关键词： statistical model parton distribution functions EMC effect

A new statistical model of wave heights based on the concept of wave breaking critical zone

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Acta Oceanologica Sinica 2015年第5期34卷 81-85页

作者： YANG Jiaxuan LI Xunqiang ZHU Shouxian ZHANG Wenjing WANG Lei Institute of Noise and Vibration Naval University of Engineering Institute of Meteorology and Marine PLA University of Science and Technology National Key Laboratory on Ship Vibration and Noise College of Harbour Coastal and Offshore EngineeringHohai University

When waves propagate from deep water to shallow water, wave heights and steepness increase and then waves roll back and break. This phenomenon is called surf. Currently, the present statistical calculation model of surf was derived mainly from the wave energy conservation equation and the linear wave dispersion relation, but it cannot reflect accurately the process which is a rapid increasing in wave height near the broken point. So, the concept of a surf breaking critical zone is presented. And the nearshore is divided as deep water zone, shallow water zone, surf breaking critical zone and after breaking zone. Besides, the calculation formula for the height of the surf breaking critical zone has founded based on flume experiments, thereby a new statistical calculation model on the surf has been established. Using the new model, the calculation error of wave height maximum is reduced from 17.62% to 6.43%.

关键词： wave height statistical model surf breaking critical zone flume experiments