检索结果-南通市图书馆

Winter wheat identification by integrating spectral and temporal information derived from multi-resolution remote sensing data

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2019年第11期18卷 2628-2643页

作者： ZHANG xi-wang LIU Jian-feng Zhenyue Qin QIN Fen key laboratory of Geospatial Technology for Middle and Lower Yellow River Regions Ministry of EducationKaifeng 475004P.R.China Research School of Computer Science The Australian National UniversityCanberra 2601Australia College of Environment and Planning Henan UniversityKaifeng 475004P.R.China Yellow River Conservancy Technical Institute Kaifeng 475004P.R.China Institute of Urban Big Data Henan UniversityKaifeng 475004P.R.China

Timely crop acreage and distribution information are the basic data which drive many agriculture related *** identifying crop types based on remote sensing,methods using only a single image type have significant *** research that integrates fine and coarser spatial resolution images,using techniques such as unmixing methods,regression models,and others,usually results in coarse resolution abundance without sufficient detail within pixels,and limited attention has been paid to the spatial relationship between the pixels from these two kinds of *** we propose a new solution to identify winter wheat by integrating spectral and temporal information derived from multi-resolution remote sensing data and determine the spatial distribution of sub-pixels within the coarse resolution ***,the membership of pixels which belong to winter wheat is calculated using a 25-m resolution resampled Landsat Thematic Mapper(TM)image based on the Bayesian ***,the winter wheat abundance(acreage fraction in a pixel)is assessed by using a multiple regression model based on the unique temporal change features from moderate resolution imaging spectroradiometer(MODIS)time series ***,winter wheat is identified by the proposed Abundance-Membership(AM)model based on the spatial relationship between the two types of ***,winter wheat is identified by comparing the spatially corresponding 10×10 membership pixels of each abundance *** other words,this method takes advantage of the relative size of membership in a local space,rather than the absolute size in the entire study *** method is tested in the major agricultural area of Yiluo Basin,China,and the results show that acreage accuracy(Aa)is 93.01%and sampling accuracy(As)is 91.40%.Confusion matrix shows that overall accuracy(OA)is 91.4%and the kappa coefficient(Kappa)is *** values are significantly improved compared to the traditional Maximum Likeli

关键词： temporal change characteristics membership abundance winter wheat multi-resolution remote sensing

Time Domain Synchronous OFDM System for Optical Fiber Communications

在线全文

学校读者我要写书评

暂无评论

China Communications 2019年第9期16卷 155-164页

作者： Chenxin Jing xianfeng Tang xiaoguang Zhang Lixia xi Wenbo Zhang State key laboratory of information Photonics and Optical Communications Beijing University of Posts and Telecommunications

A spectrum efficient OFDM scheme named Time Domain Synchronous-OFDM(TDS-OFDM)is introduced into coherent optical transmission system,in which the pseudo noise(PN)sequence is exploited as guard interval to realize frame synchronization,compensate the carrier frequency offset(CFO),and estimate and equalize channel *** there is no pilot signals or training symbols in TDS-OFDM,the proposed scheme can achieve higher spectral efficiency(SE)above 10%improvement comparing with *** proposed method is implemented and verified in a 28GBaud QPSK OFDM system and a 28GBaud 16QAM OFDM *** is demonstrated that the proposed scheme shows high CFO estimation accuracy and synchronous *** CFO and linewidth of laser source set as 100MHz and 100kHz respectively,BER of QPSK OFDM system is below 3.8e-3 at the optical signal-to-noise ratio(OSNR)of 13dB,and BER of 16QAM OFDM system is below 3.8e-3 at the OSNR of 20dB.

关键词： channel estimation carrier frequencyoffset (CFO) compensation pseudonoise (PN) sequence synchronization timedomain synchronous OFDM (TDS-OFDM)

Development and Future Challenges of Bio-Syncretic Robots

在线全文

学校读者我要写书评

暂无评论

Engineering 2018年第4期4卷 452-463页

作者： Chuang Zhang Wenxue Wang Ning xi Yuechao Wang Lianqing Liu Stute key laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Shenyang 110016 China University of Chinese Academy of Sciences Beijing 100049 China Emerging Technologies Institute Department of Industrial and Manufacturing Systems Engineering University of Hong Kong Pokfulam Hong Kong China

Bio-syncretic robots consisting of both living biological materials and non-living systems possess desirable attributes such as high energy efficiency, intrinsic safety, high sensitivity, and self-repairing capabilities. Compared with living biological materials or non-living traditional robots based on elec- tromechanical systems, the combined system of a bio-syncretic robot holds many advantages. Therefore, developing bio-syncretic robots has been a topic of great interest, and significant progress has been achieved in this area over the past decade. This review systematically summarizes the development of bio-syncretic robots. First, potential trends in the development of bio-syncretic robots are discussed. Next, the current performance of bio-syncretic robots, including simple movement and controllability of velocity and direction, is reviewed. The living biological materials and non-living materials that are used in bio-syncretic robots, and the corresponding fabrication methods, are then discussed. In addition, recently developed control methods for bio-syncretic robots, including physical and chemical control methods, are described. Finally, challenges in the development of bio-syncretic robots are discussed from multiple viewpoints, including sensing and intelligence, living and non-living materials, control approaches, and information technology.

关键词： Bio-syncretic robot Hybrid robot Bio-actuator Cardiomyocyte Muscle cells

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

基于改进YOLOv5车辆检测方法

计算机工程与设计 2024年第6期45卷 1705-1712页

作者：吕宏泽李继财杨乔楠陈学永李西兵福建农林大学机电工程学院福建福州350100 福建农林大学福建省农业信息感知技术重点实验室福建福州350100 山东劳动职业技术学院智能制造系山东济南250022

针对现有目标检测在智能交通系统和自动驾驶等领域存在车辆目标检测精度低、鲁棒性较差等问题,提出一种基于YOLOv5的车辆目标检测算法。在YOLOv5s网络模型框架中,添加注意力机制增强特征,提取重要特征;添加小目标检测层提升对遮挡重叠... 详细信息

针对现有目标检测在智能交通系统和自动驾驶等领域存在车辆目标检测精度低、鲁棒性较差等问题,提出一种基于YOLOv5的车辆目标检测算法。在YOLOv5s网络模型框架中,添加注意力机制增强特征,提取重要特征;添加小目标检测层提升对遮挡重叠弱小目标识别的准确率;引入金字塔池化(SPPFCSPC),提高网络空间特征提取能力;引入损失函数(SIoU_Loss)加快边界框回归速率,提高定位精度,消除重叠检测。基于自制车辆检测数据集进行实验,其结果表明,改进网络模型与原YOLOv5s网络模型相比,不同目标类的平均准确率均有明显提高,平均准确率均值提升3.25%,查准率提高4.14%,召回率提高3.05%,检测速度满足实时性要求。

关键词：车辆检测深度学习损失函数特征增强图像处理神经网络智能交通

Recent Advances in Nanopore sensing

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2021年第7期39卷 2035-2043页

作者： Mengjie Cui Yaxian Ge xiao Zhuge xin Zhou Dongmei xi Shusheng Zhang Shandong Provincial key laboratory of Detection Technology for Tumor Markers College of Chemistry and Chemical EngineeringLinyi UniversityLinyiShandong 276005China

Nanopore sensing is developing into a powerful label-free approach to investigate the features of biomolecules at the single-molecule *** a charged molecule is captured within a nanopore,it modulates the ionic current,which can be recorded in real time to reveal the properties of the target *** date,nanopores have been used to sense a variety of analytes,including DNA,RNA,proteins,enzymes,small molecules,cancer cells,and metal ions,and can also provide information on biomolecular *** this review,we highlight the progress made in nanopore sensing over the past five years(2016-2020),and provide an outlook on future developments and directions in the field.

关键词： Ion channels Biosensors Nanopore Biomolecule Single-molecule studies

Experimental research on oil fi lm thickness and its microwave scattering during emulsifi cation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Oceanology and Limnology 2022年第4期40卷 1361-1376页

作者： Jie GUO Chenqi XU Genwang LIU xi ZHANG Junmin MENG Guangbo REN Yantai Institute of Coastal Zone Research Chinese Academy of Sciences(CAS)CAS Key Laboratory of Coastal Environmental Processes and Ecological RemediationYantai 264003China Shandong key laboratory of Coastal Environmental Processes Yantai Institute of Coastal Zone ResearchCASYantai 264003China Center for Ocean Mega-Science CASQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China First Institute of Oceanography Ministry of Natural ResourcesQingdao 266061China

Synthetic Aperture Radar(SAR) plays a major role in identifying oil spills on the sea ***,obtaining information of oil spill thickness(volume) is still a *** is an important process affecting the thickness and normalized radar cross section(NRCS) of oil *** of crude oil emulsification with C-band fully-polarized scatterometer were conducted combining airborne hyperspectral imaging spectrometer and 3 D laser scanner observation data,to provide experimental parameters and method to support accurate remote sensing monitoring on marine oil *** is further proved that through quantitative homogeneous emulsified oil spill experiments,to a certain extent,the NRCS of oil film increased during the emulsification process of crude *** backscattering mechanism of crude oil emulsification was explored using a semi-empirical model(SEM);the change of oil film NRCS was modulated by its dielectric constant and surface roughness,in which the dielectric constant showed a dominant *** relationship between thickness and NRCS of oil film was studied under two experimental *** differences of NRCS between oil film and adjacent seawater(Δσ~0) and the damping ratio(DR) were found to have a linear relationship with oil thickness,which were best in the vertical polarization mode(VV) at 45° incident angle during the quantitative crude oil homogeneous emulsification *** the natural emulsification process of continuous oil spill in which oil film was mixed with both crude oil and emulsified oil,an empirical equation of oil film thickness is preliminarily *** Δσ~0,DR,and the empirical equation of oil film thickness were applied to the marine continuous oil spill incident on a 19-3 oil platform with spaceborne SAR image and successfully explained the distribution of the relative thickness of the oil film.

关键词： crude oil emulsifi cation normalized radar cross section(NRCS) moisture content oil fi lm thickness damping ratio 1

Influence of voxel size on forest canopy height estimates using full-waveform airborne LiDAR data

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2020年第3期7卷 392-403页

作者： Cheng Wang Shezhou Luo xiaohuan xi Sheng Nie Dan Ma Youju Huang College of Resources and Environment Fujian Agriculture and Forestry UniversityFuzhou350002China key laboratory of Digital Earth Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijing100094China Guangxi Zhuang Autonomous Region Institute of Natural Resources remote sensing Nanning530023China

Background: Forest canopy height is a key forest structure parameter. Precisely estimating forest canopy height is vital to improve forest management and ecological modelling. Compared with discrete-return LiDAR(Light Detection and Ranging), small-footprint full-waveform airborne LiDAR(FWL) techniques have the capability to acquire precise forest structural information. This research mainly focused on the influence of voxel size on forest canopy height ***: A range of voxel sizes(from 10.0 m to 40.0 m interval of 2 m) were tested to obtain estimation accuracies of forest canopy height with different voxel sizes. In this study, all the waveforms within a voxel size were aggregated into a voxel-based LiDAR waveform, and a range of waveform metrics were calculated using the voxelbased LiDAR waveforms. Then, we established estimation model of forest canopy height using the voxel-based waveform metrics through Random Forest(RF) regression *** and conclusions: The results showed the voxel-based method could reliably estimate forest canopy height using FWL data. In addition, the voxel sizes had an important influence on the estimation accuracies(R2 ranged from 0.625 to 0.832) of forest canopy height. However, the R2 values did not monotonically increase or decrease with the increase of voxel size in this study. The best estimation accuracy produced when the voxel size was 18 m(R2= 0.832, RMSE = 2.57 m, RMSE% = 20.6%). Compared with the lowest estimation accuracy, the R2 value had a significant improvement(33.1%) when using the optimal voxel size. Finally, through the optimal voxel size, we produced the forest canopy height distribution map for this study area using RF regression model. Our findings demonstrate that the optimal voxel size need to be determined for improving estimation accuracy of forest parameter using small-footprint FWL data.

关键词： Voxel size Airborne LiDAR Full-waveform Forests Canopy height

From earth observation to human observation:Geocomputation for social science

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2020年第2期30卷 233-250页

作者： LI Deren GUO Wei CHANG xiaomeng LI xi State key laboratory of information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China Collaborative Innovation Center of Geospatial Technology Wuhan 430079China Shenzhen key laboratory of Spatial Smart sensing and Services Shenzhen UniversityShenzhen 518060China

It is possible to obtain vast amounts of spatiotemporal data related to human activities to support the study of human behavior and social *** this context,geography,with the human-nature relationship as its core,is undergoing a transition from strictly earth observations to the observation of human *** for social science is one manifestation *** for social science is an interdisciplinary approach combining remote sensing techniques,social science,and big data *** by the availability of spatially and temporally expansive big data,geocomputation for social science uses spatiotemporal statistical analyses to detect and analyze the interactions between human behavior,the natural environment,and social activities;remote sensing(RS)observations are used as primary *** for social science can be used to investigate major social issues and to assess the impact of major natural and societal events,and will surely be an area of focused development in geography in the near *** briefly review the background of geocomputation in the social sciences,discuss its definition and disciplinary characteristics,and highlight the main research *** key technologies and applications are also illustrated with relevant case studies of the Syrian Civil War,typhoon transits,and traffic patterns.

关键词： geocomputation for social science nighttime light remote sensing social network traffic patterns

First-order approximate analytical expressions of oblique incident elastic wave at an interface of porous media saturated with a nonviscous fluid

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2022年第6期19卷 2720-2740页

作者： Dong-Yong Zhou xing-Yao Yin xiao-Tao Wen xi-Lei He Zhen-Hua He State key laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of TechnologyChengduSichuan610059China key laboratory of Earth Exploration and information Technology of Ministry of Education Chengdu University of TechnologyChengduSichuan610059China College of Geosciences and Technology China University of Petroleum(East China)QingdaoShandong266580China

The analysis technology of Amplitude Variation with Offset(AVO)is one of the important methods for oil and gas reservoir *** equation and its approximations are the theoretical basis of AVO analysis,which assumes that the upper and lower media of a horizontal interface are single-phase *** by this assumption,AVO analysis has limited prediction and identification accuracy for complex porous *** view of this,the first-order approximate analytical expressions of oblique elastic wave at an interface of porous media are ***,the incident and scattering characteristics of various waves at the interface of porous media are analyzed,and the displacement vectors generated by these elastic waves are described by exponential ***,the kinematic and dynamic boundary conditions at the interface of porous media are ***,by substituting the displacement vectors of incident and scattered waves into boundary conditions,the exact analytical equation is ***,considering the symmetry of scattering matrix in the equation,the exact analytical expressions of each scattered wave are ***,under the assumptions of small incident angle,weak elasticity at an interface of porous media,and ignoring the second-and higherorder terms,the first-order approximate analytical expressions are *** a model of sandstone porous media with different porosity in upper and lower media,the correctness of the approximate analytical expressions is verified,and the elastic wave response characteristics of lithology and pore fluids are analyzed.

关键词： First-order approximate expressions Oblique incident wave Elastic plane wave Porous media scattering coefficient