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Comparison of Layer-stacking and Dempster-Shafer Theory-based Methods Using Sentinel-1 and Sentinel-2 Data Fusion in Urban Land Cover Mapping

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Geo-Spatial Information Science 2022年第3期25卷 425-438页

作者： dang Hung Bui LászlóMucsi Department of Geoinformatics Physical and Environmental GeographyUniversity of SzegedSzegedHungary Institute for Environmental Science Engineering and ManagementIndustrial University of Ho Chi Minh CityHo Chi Minh CityVietnam

Data fusion has shown potential to improve the accuracy of land cover mapping,and selection of the optimal fusion technique remains a *** study investigated the performance of fusing Sentinel-1(S-1)and Sentinel-2(S-2)data,using layer-stacking method at the pixel level and Dempster-Shafer(D-S)theory-based approach at the decision level,for mapping six land cover classes in Thu Dau Mot City,*** the pixel level,S-1 and S-2 bands and their extracted textures and indices were stacked into the different single-sensor and multi-sensor datasets(*** datasets).The datasets were categorized into two *** group included the datasets containing only spectral and backscattering bands,and the other group included the datasets consisting of these bands and their extracted *** random forest(RF)classifier was then applied to the datasets within each *** the decision level,the RF classification outputs of the single-sensor datasets within each group were fused together based on D-S ***,the accuracy of the mapping results at both levels within each group was *** results showed that fusion at the decision level provided the best mapping accuracy compared to the results from other products within each *** highest overall accuracy(OA)and Kappa coefficient of the map using D-S theory were 92.67%and 0.91,*** decision-level fusion helped increase the OA of the map by 0.75%to 2.07%compared to that of corresponding S-2 products in the ***,the data fusion at the pixel level delivered the mapping results,which yielded an OA of 4.88%to 6.58%lower than that of corresponding S-2 products in the groups.

关键词： Land cover mapping data fusion random forest Dempster-Shafer theory optical data radar data pixel level decision level

Nash-equilibrium strategies of orbital TargetAttacker-Defender game with a non-maneuvering target

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Chinese Journal of Aeronautics 2024年第10期37卷 365-379页

作者： Yifeng LI Xi LIANG Zhaohui dang School of Astronautics Northwestern Polytechnical UniversityXi’an 710072China Beijing Institute of Astronautical Systems Engineering Beijing 100076China

This study investigates the orbital Target-Attacker-Defender(TAD)game problem in the context of space *** this game,the Attacker and the Defender compete for a Target that is unable to maneuver due to its original mission *** paper establishes three TAD game models based on the thrust output capabilities:unconstrained thrust output,thrust constrained by an upper bound,and fixed thrust *** models are then solved using differential game theory to obtain Nash equilibrium solutions for the game problems,and the correctness and effectiveness of the solution methods are verified through ***,an analysis of the winning mechanisms of the game is conducted,identifying key factors that influence the game’s outcomes,including weight coefficients in payoffs,the maximum thrust acceleration limit,and the initial game *** the unique characteristics of space missions,a specific focus is given to the analysis of the Defender’s initial states in the hovering formation and in-plane circling formation,revealing overall success patterns for defense strategies from these two *** summary,this study provides valuable insights into the control strategies and winning mechanisms of orbital TAD games,deepening our understanding of these games and offering practical guidance to improve success rates in real-world scenarios.

关键词： Target-Attacker-Defender problem Differential game TPBVP Continuous thrust Orbital game

Asymmetric Effects of Perceived Quality on Overall Evaluation and Moderating Effect of Sentiment:Evidence from Automobile Reviews

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Journal of Systems Science and Systems Engineering 2023年第1期32卷 16-33页

作者： Tong Yang Yanzhong dang Jiangning Wu Institute of Systems Engineering Dalian University of TechnologyDalian116024China

Perceived quality is consumers’subjective perceptions of a product’s attributes,which directly influences the overall evaluation of the *** research has suggested that the perceived quality of attributes has an asymmetric effect on the overall evaluation,but limited research has been conducted on this asymmetric effect in the automobile industry and the moderating effect of *** paper investigates the asymmetric effect of perceived quality on overall evaluation using social media data from the automobile ***,the asymmetric effect of perceived quality on overall evaluation was identified for different attributes using penalty-reward contrast analysis(PRCA),and attribute classification was realized by calculating the IA index,i.e.,Appearance is an excitement attribute and the remaining attributes are basic ***,the differences in the asymmetric effects of each attribute category were analyzed,and the basic attributes were found to have a greater effect on the overall evaluation,with a positive moderating effect of sentiment on the *** study contributes to perceived quality research as well as consumer evaluation research and provides manufacturers with a prioritization method for attribute improvement.

关键词： Perceived quality overall evaluation asymmetric effects OLS automobile reviews

Prediction on the relative permittivity of energy storage composite dielectrics using convolutional neural networks:A fast and accurate alternative to finite-element method

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iEnergy 2022年第4期1卷 463-470页

作者： shao-Long Zhong Di-Fan Liu Lei Huang Yong-Xin Zhang Qi Dong Zhi-Min dang State Key Laboratory of Power System Department of Electrical EngineeringTsinghua UniversityBeijing 100084China

The relative permittivity is one of the essential parameters determines the physical polarization behaviors of the nanocomposite dielectrics in many applications,particularly for capacitive energy *** the relative permittivity of particle/polymer nanocomposites from the microstructure is of great ***,the classical effective medium theory and physics-based numerical calculation represented by finite element method are time-consuming and cumbersome for complex structures and nonlinear *** work explores a novel architecture combining the convolutional neural network(ConvNet)and finite element method(FEM)to predict the relative permittivity of nanocomposite dielectrics with incorporated barium titanite(BT)particles in polyvinylidene fluoride(PVDF)*** ConvNet was trained and evaluated on big datasets with 14266 training data and 3514 testing data generated form a programmatic *** numerical experiments,we demonstrate that the trained network can efficiently provide an accurate agreement between the ConvNet model and FEM by virtue of the significant evaluation metrics R2,which reaches as high as 0.9783 and 0.9375 on training and testing data,*** strong universality of the presented method allows for an extension to fast and accurately predict other properties of the nanocomposite dielectrics.

关键词： Relative permittivity nanocomposite dielectrics convolutional neural networks finite element method prediction accuracy

认知因素对陕西省育龄妇女叶酸增补状况影响log-binomial模型分析

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中国公共卫生 2019年第9期35卷 1161-1165页

作者：吴天晨党少农北京大学公共卫生学院妇幼卫生学系北京100191 西安交通大学公共卫生学院流行病与卫生统计学系

目的了解叶酸增补认知对叶酸服用的影响,为妇幼保健部门提高叶酸增补干预效率、改善出生结局提供数据支撑。方法分析2016年7—8月在陕西省10个地级市和杨凌示范区开展的横断面调查数据,采用问卷调查方法对1495名近3年有过生育史或正在... 详细信息

目的了解叶酸增补认知对叶酸服用的影响,为妇幼保健部门提高叶酸增补干预效率、改善出生结局提供数据支撑。方法分析2016年7—8月在陕西省10个地级市和杨凌示范区开展的横断面调查数据,采用问卷调查方法对1495名近3年有过生育史或正在怀孕的育龄妇女围孕期叶酸服用状况和叶酸增补认知情况进行调查,采用log-binomial模型分析叶酸增补认知对叶酸服用状况的影响,估计现患比(prevalence ratio)及其95%CI,衡量叶酸增补认知状况对叶酸服用的影响程度。结果本研究纳入育龄妇女1495人,平均年龄29.27岁,叶酸服用率为84.10%。叶酸增补认知方面,围孕期增补叶酸的知晓率为86.49%,增补叶酸预防神经管畸形(NTDs)的知晓率为57.11%,叶酸免费领取的知晓率为71.35%。随着协变量的引入,认知水平和叶酸服用之间始终呈现正相关。控制了所有可能的因素后,知晓围孕期服用叶酸对叶酸服用影响的PR值为2.97(95%CI=2.33~3.93),知晓叶酸预防NTDs的PR值为1.05(95%CI=1.01~1.10)。敏感性分析显示,知晓围孕期需要服用叶酸和知晓叶酸预防NTDs在不同人群间对叶酸服用均具有显著影响(P<0.05)。结论认知是影响叶酸服用的独立因素,特别是知晓孕期服用叶酸和知晓叶酸预防NTDs对叶酸服用具有显著影响。认知因素在促进叶酸服用方面具有重要价值。

关键词：叶酸服用状况叶酸增补认知 log-binomial模型育龄妇女

Frictional sliding of infilled planar granite fracture under oscillating normal stress

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International Journal of Mining Science and Technology 2023年第6期33卷 687-701页

作者： Kang Tao Wengang dang Yingchun Li School of Civil Engineering Sun Yat-sen UniversityZhuhai 519086China State Key Laboratory of Coal Resources and Safe Mining China University of Mining and TechnologyXuzhou 221116China Southern Marine Science and Engineering Guangdong Laboratory Zhuhai 519086China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China

This paper investigates the frictional behavior of the infilled rock fracture under dynamic normal stress.A series of direct shear tests were conducted on saw-cut granite fractures infilled with quartz using a selfdeveloped dynamic shear apparatus,and the effects of normal load oscillation amplitude,normal load oscillation period and sliding velocity were *** test results reveal that the shear response can be divided into three stages over a whole loading-unloading process,characterized by different time spans and stress ***,a smaller oscillation amplitude,a longer oscillation period and a fast shear velocity promote the stability of the friction system,which is also confirmed by the Coulomb failure criterion calculated based on the observed periodic apparent friction *** dynamic strengthening/weakening phenomenon is dependent on the oscillation amplitude and product of sliding velocity and oscillation period(vT).Also,the rate and state friction law incorporating the parameter a that characterizes the normal stress variation is employed to describe the dynamic friction coefficient but exhibits an incompetent performance when handling intensive variation in normal ***,the potential seismicity induced by oscillating normal stress based on the observed stress drop is *** work helps us understand the sliding process and stability evolution of natural faults,and its benefits for relative hazard mitigation.

关键词： Granite fracture Quartz gouge Normal load oscillation Frictional stability Rate and state friction law

A Review on Flow Boiling of the Fluid with Lower Boiling Point in Micro-Channels

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Journal of Thermal Science 2024年第1期33卷 1-17页

作者： ZHANG Zhiqiang JIA Li dang Chao Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China

With the advancement of micro machining technology,the high-heat-flux removal from miniature electronic devices and components has become an attractive *** boiling in micro-channels is an optimal form of heat transfer and has been widely employed in high-heat-flux cooling *** comprehensively-reviewed article focused on the available recent literatures of experimental investigation regarding the flow boiling heat transfer and unstable behaviors of the fluid with lower boiling point in *** thermal-fluid characteristics and potential heat transfer mechanisms of low-boiling-point fluids flow boiling in different narrow passages were summarized and *** literatures regarding the pressure drop and occurrence of the unstable phenomena existing in two-phase flow boiling process were also *** emphasis was given to the heat transfer enhancement methods as well as instability elimination,and various methods such as modification of surface and channel flow geometries were *** future researches in the field of micro-scale flow boiling were suggested.

关键词： flow boiling lower boiling point fluids mini/micro-channels instabilities enhancement suppression

Optimal impulsive rendezvous for highly elliptical orbits using linear primer vector theory

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Chinese Journal of Aeronautics 2024年第3期37卷 194-207页

作者： Maozhang ZHENG Jianjun LUO Zhaohui dang National Key Laboratory of Aerospace Flight Dynamics Northwestern Polytechnical UniversityXi’an 710072China

In this paper,minimum-fuel rendezvous is investigated for the case in which the reference orbit is highly *** this end,the well-known Tschauner-Hempel equations are used to describe the relative motions between rendezvous spacecraft and the ***’s primer vector theory is then applied on this linear but time-varying *** analytical solution of the required primer vector for this problem is then derived by using a recently developed *** the existing non-optimal solutions which don’t satisfy the conditions,the methods are further designed to improve the performance by shifting impulses or adding a new ***,two algorithms are developed for free-impulse time-fixed rendezvous *** first algorithm can determine the globally optimal trajectory with the optimal number of *** second one enables for fast trajectory *** proposed algorithms have been successfully applied to coplanar and three-dimensional rendezvous problems in which the target is flying on highly elliptical orbits.

关键词： Orbital transfer Optimal trajectory Primer vector Tschauner-Hempel equations Globally planning Fast planning

SIRT7 slows down stem cell aging by preserving heterochromatin:a perspective on the new discovery

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Protein & Cell 2020年第7期11卷 469-471页

作者： Luyang Sun Weiwei dang Huffington Center on Aging Baylor College of MedicineHoustonTX 77030USA

Stem cell aging is one of the leading theories of aging and is gaining momentum in recent years with the development of new technologies to study stem cells(Schultz&Sinclair,2016).In the stem cell aging theory,the age-associated physiological changes and functional declines at tissue and organismal levels are atrbuted to changes to various stem cell populations,both in their quantity and ***,one of the pressing questions in the aging research is to understand the molecular mechanisms that preserve stem cell function and delay their aging process.

关键词： aging process. Sinclair