检索结果-南通市图书馆

Improving the spaceborne GNSS-R altimetric precision based on the novel multilayer feedforw.rd neural netw.rk w.ighted joint prediction model

引用

Defence Technology（防务技术） 2024年第2期32卷 271-284页

作者： Yiw.n Zhang w.i zheng Zongqiang Liu Qian Xuesen Laboratory of Space Technology China Academy of Space TechnologyBeijing 100094China China Academy of Aerospace Science and Innovation Beijing 100176China State Key Laboratory of Space-Ground Integrated Information Technology Beijing Institute of Satellite Information EngineeringBeijing 100194China

Global navigation satellite system-reflection(GNSS-R)sea surface altimetry based on satellite constellation platforms has become a new.research direction and inevitable trend,w.ich can meet the altimetric precision at the global scale required for underw.ter *** present,there are still research gaps for GNSS-R altimetry under this mode,and its altimetric capability cannot be specifically ***,GNSS-R satellite constellations that meet the global altimetry needs to be ***,the matching precision prediction model needs to be established to quantitatively predict the GNSS-R constellation altimetric ***,the GNSS-R constellations altimetric precision under different configuration parameters is calculated,and the mechanism of the influence of orbital altitude,orbital inclination,number of satellites and simulation period on the precision is analyzed,and a new.multilayer feedforw.rd neural netw.rk w.ighted joint prediction model is ***,the fit of the prediction model is verified and the performance capability of the model is tested by calculating the R2 value of the model as 0.9972 and the root mean square error(RMSE)as 0.0022,w.ich indicates that the prediction capability of the model is ***,using the novel multilayer feedforw.rd neural netw.rk w.ighted joint prediction model,and considering the research results and realistic costs,it is proposed that w.en the constellation is set to an orbital altitude of 500 km,orbital inclination of 75and the number of satellites is 6,the altimetry precision can reach 0.0732 m w.thin one year simulation period,w.ich can meet the requirements of underw.ter navigation precision,and thus can provide a reference basis for subsequent research on spaceborne GNSS-R sea surface altimetry.

关键词： GNSS-R satellite constellations Sea surface altimetric precision Underw.ter navigation Multilayer feedforw.rd neural netw.rk

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Bayesian Optimized LightGBM model for predicting the fundamental vibrational period of masonry infilled RC frames

引用

Frontiers of Structural and Civil Engineering 2024年第7期18卷 1084-1102页

作者： Taimur RAHMAN Pengfei zheng Shamima SULTANA Department of Civil Engineering World University of BangladeshDhaka 1230Bangladesh School of Civil Engineering Zhengzhou UniversityZhengzhou 450001China Department of Computer Science&Engineering University of Asia PacificDhaka 1205Bangladesh

The precise prediction of the fundamental vibrational period for reinforced concrete(RC)buildings w.th infilled w.lls is essential for structural design,especially earthquake-resistant *** learning models from previous studies,w.ile boasting commendable accuracy in predicting the fundamental period,exhibit vulnerabilities due to lengthy training times and inherent dependence on pre-trained models,especially w.en engaging w.th continually evolving data *** predicament emphasizes the necessity for a model that adeptly balances predictive accuracy w.th robust adaptability and sw.ft data *** latter should include consistent re-training ability as demanded by realtime,continuously updated data *** research implements an optimized Light Gradient Boosting Machine(LightGBM)model,highlighting its augmented predictive capabilities,realized through the astute use of Bayesian Optimization for hyperparameter tuning on the FP4026 research data set,and illuminating its adaptability and efficiency in predictive *** results show.that the R^(2) score of LightGBM model is 0.9995 and RMSE is 0.0178,w.ile training speed is 23.2 times faster than that offered by XGBoost and 45.5 times faster than for Gradient ***,this study introduces a practical application through a streamlit-pow.red,w.b-based dashboard,enabling engineers to effortlessly utilize and augment the model,contributing data and ensuring precise fundamental period predictions,effectively bridging scholarly research and practical applications.

关键词： masonry-infilled RC frame fundamental period LightGBM FP4026 research dataset machine learning data-driven approach Bayesian Optimization

来源：

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

Preliminary discussion on the ignition mechanism of exploding foil initiators igniting boron potassium nitrate

引用

Defence Technology（防务技术） 2024年第2期32卷 222-231页

作者： Haotian Jian Guoqiang zheng Lejian Chen zheng Ning Guofu Yin Peng Zhu Ruiqi Shen School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China Micro-Nano Energetic Devices Key Laboratory of MIIT Nanjing University of Science and TechnologyNanjing 210094China Anhui Province Key Laboratory of Microsystem the 43rd Research Institute of CETCHefei 230088China Science and Technology on Applied Physical and Chemistry Laboratory Shanxi Applied Physics and Chemistry Research Institute Xi'an 710061China

Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable w.en it comes to directly igniting *** solve the problem,this research aims to reveal the ignition mechanism of EFIs directly igniting *** oscilloscope,a photon Doppler velocimetry,and a plasma spectrum measurement system w.re employed to obtain information of electric characteristics,impact pressure,and plasma *** results of the electric characteristics and the impact pressure w.re inconsistent w.th ignition *** only thing that the ignition success tests had in common w.s that their plasma all had a relatively long period of high-temperature duration(HTD).It eventually concludes that the ignition mechanism in this research is the microconvection heat transfer rather than the shock initiation,w.ich differs from that of exploding foil initiators detonating ***,the methods for evaluating the ignition success of semiconductor bridge initiators are not entirely applicable to the tests mentioned in this *** HTD is the critical parameter for judging the ignition success,and it is influenced by tw. factors:the late time discharge and the energy of the electric *** longer time of the late time discharge and the more energy of the electric explosion,the easier it is to expand the HTD,w.ich improves the probability of the ignition success.

关键词： Exploding foil initiator PDV Plasma spectrum Ignition mechanism Boron potassium nitrate

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A Review.on the Application of Deep Learning Methods in Detection and Identification of Rice Diseases and Pests

引用

Computers, Materials & Continua 2024年第1期78卷 197-225页

作者： Xiaozhong Yu Jinhua zheng College of Computer Science and Technology Hengyang Normal UniversityHengyang421002China Hunan Provincial Key Laboratory of Intelligent Information Processing and Application Hengyang Normal UniversityHengyang421002China

In rice production,the prevention and management of pests and diseases have alw.ys received special *** methods require human experts,w.ich is costly and *** to the complexity of the structure of rice diseases and pests,quickly and reliably recognizing and locating them is ***,deep learning technology has been employed to detect and identify rice diseases and *** paper introduces common publicly available datasets;summarizes the applications on rice diseases and pests from the aspects of image recognition,object detection,image segmentation,attention mechanism,and few.shot learning methods according to the netw.rk structure differences;and compares the performances of existing ***,the current issues and challenges are explored fromthe perspective of data acquisition,data processing,and application,providing possible solutions and *** study aims to review.various DL models and provide improved insight into DL techniques and their cutting-edge progress in the prevention and management of rice diseases and pests.

关键词： Deep learning rice diseases and pests image recognition object detection

来源：

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

A Trust Evaluation Mechanism Based on Autoencoder Clustering Algorithm for Edge Device Access of IoT

引用

Computers, Materials & Continua 2024年第2期78卷 1881-1895页

作者： Xiao Feng zheng Yuan Cyber Security Academy Beijing University of Posts and TelecommunicationsBeijing100876China Department of Cyberspace Security Beijing Electronic Science and Technology InstituteBeijing100070China State Grid Info-Telecom Great Pow.r Science and Technology Co. Ltd.Beijing102211China

First,w. propose a cross-domain authentication architecture based on trust evaluation mechanism,including registration,certificate issuance,and cross-domain authentication processes.A direct trust evaluation mechanism based on the time decay factor is proposed,taking into account the influence of historical interaction *** w.ight the time attenuation factor to each historical interaction record for updating and got the new.historical record *** refer to the beta distribution to enhance the flexibility and adaptability of the direct trust assessment model to better capture time trends in the historical *** w. propose an autoencoder-based trust clustering *** perform feature extraction based on *** leibler(KL)divergence is used to calculate the reconstruction *** constructing a convolutional autoencoder,w. introduce convolutional neural netw.rks to improve training efficiency and introduce sparse constraints into the hidden layer of the *** sparse penalty term in the loss function measures the difference through the KL *** clustering is performed based on the density based spatial clustering of applications w.th noise(DBSCAN)clustering *** the clustering process,edge nodes have a variety of trustw.rthy attribute *** assign different attribute w.ights according to the relative importance of each attribute in the clustering process,and a larger w.ight means that the attribute occupies a greater w.ight in the calculation of ***,w. introduced adaptive w.ights to calculate comprehensive trust *** experiments prove that our trust evaluation mechanism has excellent reliability and accuracy.

关键词： Cross-domain authentication trust evaluation autoencoder

来源：

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

Recent advances in cancer-associated fibroblast:Biomarkers,signaling pathw.ys,and therapeutic opportunities

引用

Chinese Medical Journal 2024年第6期137卷 638-650页

作者： Donger Zhou Lei zheng Department of Hepatobiliary-Pancreatic Surgery The Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang 310009China Sidney Kimmel Comprehensive Cancer Center The Skip Viragh Pancreatic Cancer Center for Clinical Research and Careand The Bloomberg-Kimmel Institute for Immunotherapy at Johns Hopkins University School of MedicineBaltimoreMD 21287USA

Anti-cancer therapies usually focus on tumor cells,but non-tumor stromal components in the tumor microenvironment also play vital roles in tumor initiation and progression,w.ich may be the prognostic factors and potential therapeutic ***-associated fibroblasts(CAFs)are the essential component in the tumor environment,exhibiting high heterogeneity in their cell origin and phenotype w.th diverse functions that influence tumor angiogenesis,immune systems,and ***-cell RNA sequencing and genetically engineered mouse models have increased our understanding of CAF diversity,and many subtypes have been ***,the precise functions of these subtypes need to be studied and *** of signaling pathw.ys and epigenetic changes in CAFs facilitate understanding of the phenotypes of CAFs and the crosstalk betw.en tumor cells and CAFs to provide potential therapeutic *** clinical trials,including phase III trials targeting CAFs,have been performed ***,few.of these trials have generated promising results,w.ich indicates that the complexity of CAFs in the tumor microenvironment remains largely unknow.,and in-depth investigations of CAFs should be *** review.summarizes the research on CAFs,focusing on the heterogeneity of their phenotypes and functions,specific signaling pathw.ys,and the therapeutic strategies involving ***,w. briefly discuss the current technologies commonly used in CAF studies and describe the challenges and future perspectives of CAF research.

关键词： Cancer-associated fibroblasts Tumor microenvironment Anti-cancer therapy Targeted therapy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Universal method for designing periodic orbits by homotopy classes in the elliptic restricted three-body problem

引用

Astrodynamics 2024年第1期8卷 175-188页

作者： Yue zheng Min Zhao School of Electronic Engineering Xi’an Aeronautical InstituteXi’an710077China School of Aircraft Engineering Xi’an Aeronautical InstituteXi’an710077China School of Astronautics Northwestern Polytechnical UniversityXi’an710072China

The current methods for designing periodic orbits in the elliptic restricted three-body problem(ERTBP)have the disadvantages of targeting limited orbits and ergodic searches and considering only symmetric orbits.A universal method for designing periodic orbits is proposed in this ***,the homotopy classes of orbits are structured based on their topological ***,a dynamic model based on homotopy classes,ranging from the circular restricted three-body problem(CRTBP)to the ERTBP,can be built using the homotopy ***,a multi-and a single-period orbit w.re selected based on the resonance ***,the corresponding orbit in the ERTBP w.s computed by modifying the initial condition of the orbit in the *** method,w.thout an ergodic search,can extend to any orbit,including an asymmetric orbit in the CRTBP,to the ERTBP model,and the tw. orbits are of the same homotopy *** of the Earth–Moon ERTBP are presented to verify the efficiency of this method.

关键词： periodic orbit elliptic restricted three-body problem(ERTBP) topology homotopy circular restricted three-body problem(CRTBP)

来源：

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

Dopaminergic Remodeling During a Critical Developmental w.ndow.Linking Drug Use to Adult Aggression

引用

Neuroscience Bulletin 2024年第6期40卷 845-848页

作者： Dadao An Lingyan zheng zhengyi Xu Yanrong zheng Zhong Chen Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province Zhejiang Chinese Medical UniversityHangzhou310053China

Behaviors can be shaped and modulated by the dopamine system,w.ich can be remodeled in adolescents due to environmental factors,including pharmacologic exposure,stress,and rew.rding experiences,leading to various adolescentonset neuropsychiatric disorders[1-3].A deficiency of dopamine transporter(DAT),responsible for reuptaking extracellular DA.

关键词： w.ndow shaped Dopamine

来源：

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

An Example of Embedded Singular Continuous Spectrum for Discrete Schrödinger Operators

引用

Acta Mathematica Sinica,English Series 2024年第8期40卷 1837-1849页

作者： zheng Qi FU Xiong LI Laboratory of Mathematics and Complex Systems(Ministry of Education) School of Mathematical SciencesBeijing Normal UniversityBeijing 100875P.R.China

w. present an example of a potential such that the corresponding discrete Schrödinger operator has singular continuous spectrum embedded in the absolutely continuous spectrum.

关键词： Sparse potentials singular continuous spectrum Prüfer variables

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Slow.ng dow. of the summer Southern Hemisphere Annular Mode trend against the background of ozone recovery

引用

Atmospheric and Oceanic Science Letters 2024年第1期17卷 1-8页

作者： Fei zheng School of Atmospheric Sciences Key Laboratory of Tropical Atmosphere-Ocean SystemMinistry of EducationSun Yat-sen UniversityZhuhaiChina Southern Marine Science and Engineering Guangdong Laboratory ZhuhaiChina

20世纪末期,南半球热带外地区经历了显著的气候变化,包括夏季南半球环状模(SAM)的显著上升趋势,伴随着南极半岛的增暖和别林斯高晋海的海冰融化.这些趋势主要是由20世纪末期南极平流层臭氧消耗所驱动的.本文发现,自2001年左右以来,在南... 详细信息

20世纪末期,南半球热带外地区经历了显著的气候变化,包括夏季南半球环状模(SAM)的显著上升趋势,伴随着南极半岛的增暖和别林斯高晋海的海冰融化.这些趋势主要是由20世纪末期南极平流层臭氧消耗所驱动的.本文发现,自2001年左右以来,在南极平流层臭氧恢复的背景下,观测到的夏季SAM的上升趋势已经趋于平缓,验证了前人利用数值模拟预测的夏季SAM上升趋势减缓现象,与SAM在臭氧恢复后趋势只减缓但没有逆转不同,南极地表气温和海冰的趋势发生了逆转.南极半岛由变暖趋势转为降温趋势,别林斯高晋海域的海冰由融化趋势转为增多趋势.

关键词：南半球环状模南极臭氧损耗南极臭氧恢复

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：