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Partition of GB-InSAR deformation map based on dynamic time warping and k-means

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Journal of Systems Engineering and Electronics 2022年第4期33卷 907-915页

作者： TIAN Weiming DU Lin DENG Yunkai dong xichao Radar Research Lab School of Information and ElectronicsBeijing Institute of TechnologyBeijing 100081China Key Laboratory of Electronic and Information Technology in Satellite Navigation(Beijing Institute of Technology) Ministry of EducationBeijing 100081China School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Centre Chongqing 401120China Advanced Technology Research Institute Beijing Institute of TechnologyJi'nan 250300China

Ground-based interferometric synthetic aperture radar(GB-InSAR)can take deformation measurement with a high *** of the GB-InSAR deformation map benefits analyzing the deformation state of the monitoring scene *** partition methods rely on labelled datasets or single deformation feature,and they cannot be effectively utilized in GBInSAR *** paper proposes an improved partition method of the GB-InSAR deformation map based on dynamic time warping(DTW)and *** DTW similarities between a reference point and all the measurement points are calculated based on their time-series *** the DTW similarity and cumulative deformation are taken as two partition *** the k-means algorithm and the score based on multi evaluation indexes,a deformation map can be partitioned into an appropriate number of *** datasets of West Copper Mine are processed to validate the effectiveness of the proposed method,whose measurement points are divided into seven classes with a score of 0.3151.

关键词： ground-based interferometric synthetic aperture radar(GB-InSAR) deformation map partition dynamic time warping(DTW) k-means

超早期经脑沟裂入路与经脑回皮质入路显微手术治疗基底节区脑出血的疗效分析

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中华脑科疾病与康复杂志（电子版） 2024年第2期14卷 100-105页

作者：董西朝王林林袁致海高文文西安医学院第二附属医院神经外科西安710038

目的比较超早期经脑沟裂入路与经脑回皮质入路显微手术治疗基底节区脑出血的疗效。方法选择西安医学院第二附属医院神经外科自2021年1月至2022年12月收治的122例基底节区脑出血患者进行回顾性分析。所有患者均在发病后7 h进行手术,并根... 详细信息

目的比较超早期经脑沟裂入路与经脑回皮质入路显微手术治疗基底节区脑出血的疗效。方法选择西安医学院第二附属医院神经外科自2021年1月至2022年12月收治的122例基底节区脑出血患者进行回顾性分析。所有患者均在发病后7 h进行手术,并根据手术方法分为2组,其中脑沟裂入路组68例,脑回皮质入路组54例。比较2组患者的手术相关指标、并发症发生率,术前、术后7 d血清NE和5-HT水平,术前、术后30 d美国国立卫生研究院卒中量表(NIHSS)、斯堪的纳维亚卒中量表(SSS)评分,以及术后30 d预后情况。结果2组患者手术时间、血肿清除率、术中出血量、住院时间及再出血发生率比较,差异均无统计学意义(P>0.05)。术后7 d,2组患者血清5-HT、NE水平较术前明显升高,且脑沟裂入路组高于脑回皮质入路组,差异均有统计学意义(P<0.05)。术后30 d,2组患者NIHSS评分较术前明显降低,SSS评分较术前明显升高,且脑沟裂入路组NIHSS评分低于脑回皮质入路组,SSS评分高于脑回皮质入路组,差异均有统计学意义(P<0.05)。脑沟裂入路组的预后良好率(94.12%)高于脑回皮质入路组(66.66%),差异有统计学意义(P<0.05)。结论超早期经脑沟裂入路显微手术治疗基底节区脑出血的疗效优于经脑回皮质入路显微手术,可减轻对5-HT、NE的抑制,有助于神经功能的恢复。

关键词：经脑沟裂入路经脑回皮质入路显微手术基底节区脑出血 5-羟色胺去甲肾上腺素神经功能

Lateral root elongation in maize is related to auxin synthesis and transportation mediated by N metabolism under a mixed NO_(3)^(–) and NH_(4)^(+) supply

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Journal of Integrative Agriculture 2024年第3期23卷 1048-1060页

作者： Peng Wang Lan Yang xichao Sun Wenjun Shi Rui dong Yuanhua Wu Guohua Mi Key Laboratory of Tobacco Biology and Processing of Ministry of Agriculture and Rural Affairs Tobacco Research InstituteChineseAcademy of Agricultural SciencesQingdao 266101China Department of Plant Nutrition College of Resources and Environmental SciencesChina Agricultural UniversityBeijing 100193China College of Resources Hunan Agricultural UniversityChangsha 410128China Agro-Environmental Protection Institute Ministry of Agriculture and Rural AffairsTianjin 300191China

A mixed nitrate (NO_(3)^(–)) and ammonium (NH_(4)^(+)) supply can promote root growth in maize (Zea mays),however,the changes in root morphology and the related physiological mechanism under different N forms are still ***,maize seedlings were grown hydroponically with three N supplied in three different forms (NO_(3)^(–)only,75/25 NO_(3)^(–)/NH_(4)^(+)and NH_(4)^(+)only).Compared with sole NO_(3)^(–)or NH_(4)^(+),the mixed N supply increased the total root length of maize but did not affect the number of axial *** main reason was the increased total lateral root length,while the average lateral root (LR) length in each axle was only slightly *** addition,the average LR density of 2nd whorl crown root under mixed N was also *** with sole nitrate,mixed N could improve the N metabolism of roots (such as the N influx rate,nitrate reductase (NR) and glutamine synthase (GS)enzyme activities and total amino content of the roots).Experiments with exogenously added NR and GS inhibitors suggested that the increase in the average LR length under mixed N was related to the process of N assimilation,and whether the NR mediated NO synthesis participates in this process needs further ***,an investigation of the changes in root-shoot ratio and carbon (C) concentration showed that C transportation from shoots to roots may not be the key factor in mediating lateral root elongation,and the changes in the sugar concentration in roots further proved this ***,the synthesis and transportation of auxin in axial roots may play a key role in lateral root elongation,in which the expression of ZmPIN1B and ZmPIN9 may be involved in this *** study preliminarily clarified the changes in root morphology and explored the possible physiological mechanism under a mixed N supply in maize,which may provide some theoretical basis for the cultivation of crop varieties with high N efficiency.

关键词： maize NO_(3)^(–)/NH_(4)^(+)ratio lateral root elongation N assimilation indole-3-acetic acid

Optimal 3D deformation measuring in inclined geosynchronous orbit SAR differential interferometry

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Science China(Information Sciences) 2017年第6期60卷 33-47页

作者： Cheng HU Yuanhao LI xichao dong Rui WANG Chang CUI School of Information and Electronics Beijing Institute of Technology Key Laboratory of Electronic and Information Technology in Satellite Navigation (Beijing Institute of Technology) Ministry of Education

Three dimensional(3D) deformation can be obtained by using differential interferometric synthetic aperture radar(D-In SAR) technique with the cross-heading tracks data of low earth orbit(LEO) SAR. However,this method has drawbacks of the low temporal sampling rate and the limited area and accuracy for 3D deformation retrieval. To address the aforementioned problems, by virtue of a geosynchronous(GEO) SAR platform,this paper firstly demonstrates the expressions of 3D deformation and the corresponding errors in GEO SAR multi-angle processing. An optimal multi-angle data selection method based on minimizing position dilution of precision(PDOP) is proposed to obtain a good 3D deformation retrieval accuracy. Moreover, neural network is utilized for analyzing the accuracy of the retrieved 3D deformation under different orbit configurations and geo-locations. Finally, the proposed methods and the theoretical analysis are verified by simulation experiments.A 3D deformation retrieval accuracy of the order of centimeter-level or even millimeter-level can be obtained by using the selected optimal multi-angle data.

关键词： geosynchronous synthetic aperture radar(GEO SAR) three dimensional(3D) deformation mea surement multi-angle processing differential SAR(D-InSAR) neural network

Simulation and Analysis of the Impacts of Anisotropic Ionospheric Scintallition on Geosynchronous Synthetic Aperture Radar

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Journal of Beijing Institute of Technology 2017年第1期26卷 115-120页

作者： Yinhui Xu xichao dong Cheng Hu Yuanhao Li School of Information and Electronics Beijing Institute of Technology Beijing 100081 China Beijing Key Laboratory of Embedded Real-time Information Processing Technology Beijing 100081 China

The impacts of ionospheric scintillation on geosynchronous synthetic aperture radar（GEO SAR）focusing is studied based on the multiple phase screen（MPS）*** power spectrum density of electron irregularities is first modified according to the ionospheric *** propagation wave equations in random medium are deduced in the case of oblique incidence in GEO *** amplitude and phase errors induced by the random electron fluctuations are generated by the iterated MPS simulations and are superimposed into the GEO SAR *** the following imaging and evaluation,the effects of the anisotropic ionospheric scintallition on GEO SAR are *** last,the optimized integration time under different ionospheric scintillation conditions are recommended through Monte Carlo *** is concluded that,greater ionospheric fluctuations and longer integration time will result in more severe deterioration,even no focus at all in the worst case.

关键词： anisotropy focusing geosynchronous synthetic aperture radar (GEO SAR) ionospher-ic scintillation multiple phase screen

Feasibility study of inclined geosynchronous SAR focusing using Beidou IGSO signals

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Science China Earth Sciences 2016年第12期59卷 240-242页

作者： xichao dong Cheng HU Weiming TIAN Tian ZHANG Yuanhao LI Beijing Key Laboratory of Embedded Real-time Information Processing Technology Beijing Institute of Technology

Dear editor,Geosynchronous synthetic aperture radar(GEO SAR)[1,2]has an inclined geosynchronous orbit of around 36000 km,which leads to its short revisit time of around 24 hours and a wide coverage of up to approximately one third of the Earth *** long integration time guarantees the fine ***,GEO SAR owns the promising capability of providing images with the high resolution,

关键词：倾斜地球同步轨道 SAR 北斗聚焦信号

Impacts of ionospheric scintillation on geosynchronous SAR focusing: preliminary experiments and analysis

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Science China(Information Sciences) 2015年第10期58卷 191-193页

作者： LI YuanHao HU Cheng dong xichao TIAN WeiMing LONG Teng Beijing Key Laboratory of Embedded Real-time Information Processing Technology Beijing Institute of Technology

Dear editor,Geosynchronous Synthetic Aperture Radar(GEO SAR)has significant potential when applied to hazard and disaster monitoring because of its short revisit time of approximately 24 h and its wide coverage of app... 详细信息

关键词： SAR Impacts of ionospheric scintillation on geosynchronous SAR focusing GEO PSLR Figure preliminary experiments and analysis than

Research progress on geosynchronous synthetic aperture radar

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Fundamental Research 2021年第3期1卷 346-363页

作者： Cheng Hu Zhiyang Chen Yuanhao Li xichao dong Stephen Hobbs The School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China Advanced Technology Research Institute Beijing Institute of TechnologyJinan 250300China The Key Laboratory of Electronic and Information Technology in Satellite Navigation(Beijing Institute of Technology) Ministry of EducationBeijing 100081China Department of Geoscience and Remote Sensing Delft University of Technology2628 Delftthe Netherlands Beijing Institute of Technology Chongqing Innovation Center Chongqing 401120China The School of Aerospace Transport&Manufacturing Cranfield UniversityUK

Based on its ability to obtain two-dimensional(2D)high-resolution images in all-time and all-weather conditions,spaceborne synthetic aperture radar(SAR)has become an important remote sensing technique and the study of such systems has entered a period of vigorous *** imaging modes such as radar interferometry,tomography,and multi-static imaging,have been ***,current in-orbit spaceborne SARs,which all operate in low Earth orbits,have relatively long revisit times ranging from several days to dozens of days,restricting their temporal sampling *** SAR(GEO SAR)is an active research area because it provides significant new capability,especially its much-improved temporal *** paper reviews the research progress of GEO SAR technologies in *** typical orbit schemes are presented,followed by the corresponding key issues,including system design,echo focusing,main disturbance factors,repeat-track interferometry,etc,inherent to these *** analysis and solution research of the above key issues are *** SAR concepts involving multiple platforms are described,including the GEO SAR constellation,GEO-LEO/airborne/unmanned aerial vehicle bistatic SAR,and formation flying GEO SAR(FF-GEO SAR).Due to the high potential of FF-GEO SAR for three-dimensional(3D)deformation retrieval and coherence-based SAR tomography(TomoSAR),we have recently carried out some research related to FF-GEO *** research,which is also discussed in this paper,includes developing a formation design method and an improved TomoSAR processing *** is found that GEO SAR will continue to be an active topic in the aspect of data processing and multi-platform concept in the near future.

关键词： Geosynchronous synthetic aperture radar(GEO SAR) Orbit scheme Disturbance factors Echo focusing Formation flying

时空变背景电离层对GEO TomoSAR成像影响分析

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信号处理 2019年第6期35卷 1018-1024页

作者：张彬董锡超胡程北京理工大学信息与电子学院雷达技术研究所北京100081 卫星导航电子信息技术教育部重点实验室(北京理工大学) 北京100081

地球同步轨道合成孔径雷达层析成像(GEOTomoSAR)是一种将地球同步轨道SAR(GEOSAR)与三维层析成像相结合的技术,它能够克服低轨SAR层析成像中重访时间长、时间去相干严重等缺点,实现对地面场景及时、精确地三维重建。但是由于GEOSAR轨道... 详细信息

地球同步轨道合成孔径雷达层析成像(GEOTomoSAR)是一种将地球同步轨道SAR(GEOSAR)与三维层析成像相结合的技术,它能够克服低轨SAR层析成像中重访时间长、时间去相干严重等缺点,实现对地面场景及时、精确地三维重建。但是由于GEOSAR轨道高,信号能够穿过整个电离层,使得GEOSAR信号时延长,引入严重的相位误差,进而影响GEOTomoSAR三维成像的精度。本文主要从背景电离层对雷达信号传播的影响机理出发,建立了时空变背景电离层影响下的GEOTomoSAR信号模型,进而分析了对三维成像的影响。经过分析,时空变背景电离层对GEOTomoSAR系统的影响主要包括成像目标的相对位置偏移以及高度向成像散焦。最后,通过计算机仿真验证了理论分析的正确性。

关键词：背景电离层时空变地球同步轨道SAR 层析成像