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Segmentation of thermal infrared images of cucumber leaves using K-means clustering for estimating leaf wetness duration

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International Journal of Agricultural and Biological Engineering 2020年第3期13卷 161-167页

作者： Dongmei Wen Aixin Ren Tao Ji Isabel Maria Flores-Parra Xinting Yang Ming Li Beijing Research Center for information Technology in Agriculture/National Engineering Research Center for information Technology in Agriculture/National Engineering laboratory for Agri-product Quality Traceability/National meteorological Service Center of Urban Agriculture Beijing 100097China College of Plant Protection China Agricultural UniversityBeijing 100193China department of Sustainable Crop Production UniversitàCattolica del Sacro Cuore29122 PiacenzaItaly department of Informatics University of AlmeriaAlmeriaCP04120Spain

Leaf wetness duration(LWD)is a critical parameter used to predict plant disease,but its determination under actual field conditions is a major *** this study,a method for determining LWD using thermal infrared imaging was developed and applied to cucumber plants grown in a solar *** images of the plant leaves were captured using an infrared scanning camera,and a leaf wetness area segmentation method consisting of two procedures was ***,a color space conversion was performed automatically by an image-processing ***,the K-means clustering algorithm was applied to enable the segmentation of the wetness area on the thermal ***,to enable overall thermal image analysis,an initial leaf wetness threshold(LWT)of 5%was defined(where wetness values higher than 5%indicated that the leaf was in a wet state).The results of comparative experiments conducted using thermal images of plant leaves captured using an infrared scanning camera and human visual observation indicated that the estimated LWD values were generally higher than the observed LWD values,because slight leaf wetness condensations were overlooked by the human eye but detected by the infrared scanning *** these differences were not found to be statistically significant in this study,the proposed method for determining LWD using thermal infrared imaging may provide a new LWD detection method for cucumber and other plants grown in solar greenhouses.

关键词： thermal imaging K-means clustering algorithm leaf wetness duration cucumber

Downscaling inversion of GRACE-derived groundwater storage changes based on ensemble learning

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International Journal of Digital Earth 2023年第1期16卷 2998-3022页

作者： Pengao Li Haiyang Yu Peng Zhou Ping Zhang Ruili Wang School of Surveying and Land information Engineering Henan Polytechnic UniversityJiao ZuoPeople’s Republic of China key laboratory of Mine Spatio-Temporal information and Ecological Restoration Ministry of Natural ResourcesHenan Polytechnic UniversityJiao ZuoPeople’s Republic of China

Gravity Recovery and Climate Experiment(GRACE)satellite data monitors changes in terrestrial water storage,including groundwater,at a regional ***,the coarse spatial resolution limits its applicability to small watershed *** study introduces a novel ensemble learning-based model using meteorological and topographical data to enhance spatial *** effectiveness was evaluated using groundwater-level observation data from the Henan rainstorm-affected area in July *** factors influencing Groundwater Storage Anomalies(GWSA)were explored using Permutation Importance(Pi)and other *** results demonstrate that feature engineering and Blender ensemble learning improve downscaling accuracy;the Root Mean Square Error(RMSE)can be reduced by up to 18.95%.Furthermore,Blender ensemble learning decreased the RMSE by 3.58%,achieving an R-Square(R3)value of *** the downscaling inversion to June-August data greatly enhanced the accuracy,as evidenced by a holdout dataset test with an R2 value of *** overall GWSA variation from January to August exhibited'slow rise,slow fall,sharp fall,and sharp ***,heavy rain exhibits a lag effect on the groundwater *** and topographical factors drive fluctuations in GwSA values and changes in spatial *** activities also have a significant impact.

关键词： GRACE gravity satellites ensemble learning model groundwaterreserve '7.20'Henan rainstorm

Non-Exchangeable Error Compensation for Strapdown Inertial Navigation System in High Dynamic Environment

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Computers, Materials & Continua 2020年第8期64卷 973-986页

作者： Qi Wang Changsong Yang Shao’en Wu School of Computer and Software Nanjing University of Information Science and TechnologyNanjing210044China jiangsu Engineering Center of Network Monitoring Nanjing University of Information Science and TechnologyNanjing210044China School of Automation Nanjing University of Information Science and TechnologyNanjing210044China department of Computer Science Ball State UniversityMuncie47306USA

Strapdown non-exchangeable error compensation technology in high dynamic environment is one of the key technologies of strapdown inertial navigation *** platform is used in strapdown inertial navigation system instead of physical platform in traditional platform inertial navigation system,which improves reliability and reduces cost and volume of *** maximum error source of attitude matrix solution is the non-exchangeable error of rotation due to the non-exchangeable of finite rotation of rigid *** rotation non-exchangeable error reaches the maximum in coning motion,although it can be reduced by shortening the correction period and increasing the real-time *** equivalent rotation vector method is used to modify the attitude to reduce the coning error in this *** experiments show that the equivalent rotation vector method can effectively suppress the non-exchangeable error and improve the accuracy of attitude calculation.

关键词： Strapdown error compensation coning motion equivalent rotation vector simulation experiments

Computer vision-based method for monitoring grain quantity change in warehouses

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Grain & Oil Science and Technology 2020年第3期3卷 87-99页

作者： Lei Li Xuan Fei Zhuoli Dong Tiejun Yang key laboratory of Grain information processing and Control(Henan University of Technology) Ministry of EducationZhengzhou 450001China College of information Science and Engineering Henan University of TechnologyZhengzhou 450001China

Regularly checking the quantity of stored grain in warehouses is essential for the grain safety of a ***,current manual inspection ways fail to get real-time measurement results and require spending a lot of manpower and *** this paper,we proposed a computer vision-based method to automatically monitor the change in grain quantity of a *** proposed method was motivated from the observation that warehouse managers can use a camera to remotely monitor the grain security of a granary,which determines whether grain quantity is reduced by checking the distance between the grain surface and the grain loading line at the outlet of a *** this end,images were first captured by a camera,and a two-level spatial constraints-based SVM classifier was learned to detect the grain surface and the grain loading line of the *** the test phase,the detected result of a test image obtained by SVM was further refined by Grab Cut with higher order potentials to get the more accurate segmentation ***,the area between the grain surface and the grain loading line was calculated,and then compared with the previous measured one to determine whether the grain surface had *** experiment results validate the effectiveness of the two-level spatial constraints SVM and the strategy for monitoring the change in grain quantity.

关键词： Image segmentation Grain safety SVM Spatial constraints Computer vision

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Comparison of Extrapolation and Interpolation Methods for Estimating Daily Photosynthetically Active Radiation(PAR)——A Case Study of the Poyang Lake National Nature Reserve,China

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Geo-Spatial information Science 2010年第4期13卷 235-242页

作者： WU Guofeng Jan de Leeuw Andrew K. Skidmore LIU Yaolin Herbert H. T. Prins School of Resource and Environmental Science Wuhan University 129 Luoyu Road Wuhan 430079 China key laboratory of Geographic information System of the Ministry of Education Wuhan University 129 Luoyu Road Wuhan 430079 China International Livestock Research Institute (ILRI) P. O. Box 30709 Nairobi 00100 Kenya department of Natural Resources International Institute for Geo-Information Science and Earth Observation P. O. Box 6 Hengelosestraat 99 7500 AA Enschede the Netherlands Resource Ecology Group Department of Environmental Sciences Wageningen University Droevendaalsesteeg 3A 6708 PB Wageningen the Netherlands

Measurements of photosynthetically active radiation （PAR）, which are indispensable for simulating plant growth and productivity, are generally very scarce. This study aimed to compare two extrapolation and one interpolation methods for estimating daily PAR reaching the earth surface within the Poyang Lake national nature reserve, China. The daily global solar radiation records at Nanchang meteorological station and daily sunshine duration measurements at nine meteorological stations around Poyang Lake were obtained to achieve the objective. Two extrapolation methods of PARs using recorded and estimated global solar radiation at Nanchang station and three stations （Yongxiu, Xingzi and Duchang） near the nature reserve were carried out, respectively, and a spatial interpolation method combining triangulated irregular network （TIN） and inverse distance weighting （IDW） was imple- mented to estimate daily PAR. The performance evaluation of the three methods using the PARs measured at Dahuchi Conservation Station （day number of measurement = 105 days） revealed that：（1） the spatial interpolation method achieved the best PAR estima- tion （R2 - 0.89, s.c. = 0.99, F= 830.02, P 〈 0.001 ）; （2） the extrapolation method from Nanchang station obtained an unbiased result （R2 = 0.88, s.c. = 0.99, F = 745.29, P 〈 0.001）; however, （3） the extrapolation methods from Yongxiu, Xingzi and Duchang stations were not suitable for this specific site for their biased estimations. Considering the assumptions and principles supporting the extrapolation and interpolation methods, the authors conclude that the spatial interpolation method produces more reliable results than the extrapolation methods and holds the greatest potential in all tested methods, and more PAR measurements should be recorded to evaluate the seasonal, yearly and spatial stabilities of these models for their application to the whole nature reserve of Poyang Lake.

关键词： photosynthetically active radiation (PAR) extrapolation interpolation triangulated irregular network (TIN) inverse distance weighting (IDW)

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Spatial character of the gaseous and particulate state compound correlation of urban atmospheric pollution in winter and summer

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Science China Earth Sciences 2005年第S2期48卷 64-79页

作者： XU Xiangde, SHI Xiaohui, XIE Lian, DING Guoan, MIAO Qiuju, MA Jianzhong & ZHENG Xiangdong State key laboratory of Severe Weather, Chinese Academy of meteorological Sciences, Beijing 100081, China Nanjing University of information Science and Technology, Nanjing 210044, China department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC27695-8208, USA National Climate Center, China meteorological Administration, Beijing 100081, China State key laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081 China State key laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081 China Nanjing University of information Science and Technology Nanjing 210044 China department of Marine Earth and Atmospheric Sciences North Carolina State University Raleigh NC27695-8208 USA National Climate Center China Meteorological Administration Beijing 100081 China

The spatial/temporal variation information of atmospheric dynamic-chemical processes at observation site points of the "canopy" boundary of Beijing urban building ensemble and over urban area "surface", as well as the seasonal correlation structure of the gaseous and par-ticulate states of urban atmospheric pollution (UAP) and its seasonal conversion feature at observation points are investigated, using the comprehensive observation data of the Beijing City Air Pollution observation Experiment (BECAPEX) in winter and summer 2003 with a "point-surface" combined research approach. By using "one dimension spatial empirical orthogonal function (EOF)" principal component analysis (PCA) mode, the seasonal change of gaseous and particulate states of atmospheric aerosols and the association feature of pollutant species under the background of the complicated structure of urban boundary layer (UBL) are analyzed. The comprehensive analyses of the principal components of particle concentrations, gaseous pollutant species, and meteorological conditions reveal the seasonal changes of the complex constituent and structure features of the gaseous and particulate states of UAP to further trace the impact feature of urban aerosol pollution surface sources and the seasonal difference of the component structure of UAP. Research results suggest that in the temporal evolution of the gaseous and particulate states of winter/summer UAP, NOx, CO, and SO2 showed an "in-phase" evolution feature, however, O3 showed an "inverse-phase" relation with other species, all possessing distinctive dependent feature. On the whole, summer concentrations of gaseous pollutants CO, SO2, and NOx were obviously lower than winter ones, especially, the reduction in CO concentration was most distinctive, and ones in SO2 and NOx were next. However, the summer O3 concentration was more than twice winter one. Winter/summer differences in PM10 and PM2.5 particle concentrations were relatively not obvious, which ind

关键词： aerosol correlation structure principal component analysis.

Overview and preliminary idea for building Digital Earth with Grid computing technology

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International Journal of Digital Earth 2008年第2期1卷 240-245页

作者： Yong Xue Huadong Guo Wei Wan Jianqin Wang Ying Luo Centre for Earth observation and Digital Earth Sciences Chinese Academy of SciencesBeijingChina department of Computing London Metropolitan UniversityLondonUK State key laboratory of Remote Sensing Science Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal UniversityInstitute of Remote Sensing ApplicationsChinese Academy of SciencesBeijingChina Graduate School Chinese Academy of SciencesBeijingChina

Digital Earth is an important field of information technology and a research frontier of geosciences in the 21st *** far,the Grid computing technique is one of the best solutions for Digital Earth *** Earth can only be realised through the interaction of people,heterogeneous computing resources,information systems,and instruments,all of which are geographically and organisationally *** observation(EO)includes information acquisition,processing and *** acquisition provides a vast amount of spatial data for building the fabric resource *** processing means that spatial information processing middleware is used with large amounts of secure Grid computing resources for real-time processing of all kinds of spatial *** are currently working on the development of coremiddleware for EO data processing and applications for the Digital Earth Prototype System,which is available in the Institute of Remote Sensing Applications(IRSA),Chinese Academy of Sciences(CAS)The further results will be available soon.

关键词： Digital Earth Grid computing spatial information Grid

A scalable cyberinfrastructure and cloud computing platform for forest aboveground biomass estimation based on the Google Earth Engine

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International Journal of Digital Earth 2019年第9期12卷 995-1012页

作者： Zelong Yang Wenwen Li Qi Chen Sheng Wu Shanjun Liu Jianya Gong The State key laboratory of information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhanPeople’s Republic of China School of Geographical Sciences and Urban Planning Arizona State UniversityTempeAZUSA department of Geography and Environment University of Hawaii at MānoaHonoluluHIUSA School of Computer and information Science Southwest UniversityChongqingPeople’s Republic of China School of Resources and Civil Engineering Northeastern UniversityShenyang

Earth observation(EO)data,such as high-resolution satellite imagery or LiDAR,has become one primary source for forests Aboveground Biomass(AGB)mapping and ***,managing and analyzing the large amount of globally or locally available EO data remains a great *** Google Earth Engine(GEE),which leverages cloud-computing services to provide powerful capabilities on the management and rapid analysis of various types of EO data,has appeared as an inestimable tool to address this *** this paper,we present a scalable cyberinfrastructure for on-the-fly AGB estimation,statistics,and visualization over a large spatial *** cyberinfrastructure integrates state-of-the-art cloud computing applications,including GEE,Fusion Tables,and the Google Cloud Platform(GCP),to establish a scalable,highly extendable,and highperformance analysis *** experiments were designed to demonstrate its superiority in performance over the traditional desktop environment and its scalability in processing complex *** addition,a web portal was developed to integrate the cyberinfrastructure with some visualization tools(*** Maps,Highcharts)to provide a Graphical User Interfaces(GUI)and online visualization for both general public and geospatial researchers.

关键词： Above ground biomass cloud computing Google Earth Engine visualization

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声波超材料中D类拓扑的观测

Science Bulletin 2024年第7期69卷 893-900页

作者：吴世巧程文婷刘啸宇吴柄权 Emil Prodan Camelia Prodan 蒋建华 School of Physical Science and Technology&Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow UniversitySuzhou 215006China School of Physics and Optoelectronic Engineering Foshan UniversityFoshan 528000China Guangdong-Hong Kong-Macao Joint laboratory for Intelligent Micro-Nano Optoelectronic Technology Foshan UniversityFoshan 528000China department of Physics University of MichiganAnn Arbor MI 48109USA department of Physics Yeshiva UniversityNew York NY 10033USA department of Physics and Engineering Physics Fordham UniversityNew York NY 10023USA Suzhou Institute for Advanced Research University of Science and Technology of ChinaSuzhou 215123China

Topological materials and metamaterials opened new paradigms to create and manipulate phases of matter with unconventional *** D-class phases(TDPs)are archetypes of the ten-fold classification of topological phases with particle-hole *** two dimensions,TDPs support propagating topological edge modes that simulate the elusive Majorana elementary ***,a piercing ofπ-flux Dirac-solenoids in TDPs stabilizes localized Majorana excitations that can be braided for the purpose of topological quantum *** two-dimensional(2D)TDPs have been a focus in the research frontier,but their experimental realizations are still under ***,with a novel design scheme,we realize 2D TDPs in an acoustic crystal by synthesizing both the particle-hole and fermion-like time reversal symmetries for a wide range of *** design scheme leverages an enriched unit cell structure with real-valued couplings that emulate the targeted Hamiltonian of TDPs with complex hoppings:A technique that could unlock the realization of all topological classes with passive *** our experiments,we realize a pair of TDPs with opposite Chern numbers in two independent sectors that are connected by an intrinsic fermion-like timereversal symmetry built in the *** measure the acoustic Majorana-like helical edge modes and visualize their robust topological transport,thus revealing the unprecedented D and DIII class topologies with direct *** study opens up a new pathway for the experimental realization of two fundamental classes of topological phases and may offer new insights in fundamental physics,materials science,and phononic information processing.

关键词： D-class topology Chiral symmetry Time-reversal symmetry Particle-hole symmetry Gapless edge states

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