检索结果-南通市图书馆

基于COSMIC掩星数据探测汶川M_S8.0地震震前电离层异常

在线全文

学校读者我要写书评

暂无评论

地震学报 2013年第6期35卷 848-855,938页

作者：马新欣林湛陈化然金红林李大虎焦立果刘晓灿中国地震局地球物理研究所中国北京100081 中国地震局地震预测研究所中国北京100036 四川省地震局工程地震研究院中国成都610041

获取COSMIC掩星2级数据,基于球谐函数使用最小二乘拟合法计算模型值,为2008年5月12日汶川MS8.0地震前电离层电子密度变化提供背景依据.同时应用主成分分析法研究最大电子密度,得到各主成分所占能量百分比随时间的变化.研究结果发现,震... 详细信息

获取COSMIC掩星2级数据,基于球谐函数使用最小二乘拟合法计算模型值,为2008年5月12日汶川MS8.0地震前电离层电子密度变化提供背景依据.同时应用主成分分析法研究最大电子密度,得到各主成分所占能量百分比随时间的变化.研究结果发现,震前在震中邻近区域出现电离层扰动增强现象,且随高度不同存在一定差异,主要集中在F2层300—450km.主成分分析结果显示,4月15日—29日19:00—24:00(地方时)第三主成分能量百分比显著增加.上述结果表明,震前电离层存在异常扰动现象.这一研究结果有助于加强地震电离层耦合机理方面的研究.

关键词： COSMIC 球谐函数最小二乘拟合法电离层扰动

利用块体-位错模型反演华北地区块体运动和断裂活动

在线全文

学校读者我要写书评

暂无评论

大地测量与地球动力学 2014年第4期34卷 39-42,48页

作者：朱泽孟国杰苏小宁金红林胡新康 Ge Linlin 中国地震局地震预测重点实验室(中国地震局地震预测研究所) 北京100036 浙江省地震局杭州310013 中国地震局第一监测中心天津300180 澳大利亚新南威尔士大学

对华北地区1999以来的GPS观测数据进行处理,得到统一的GPS速度场。建立华北地区块体-位错模型,利用模拟退火方法,反演主要块体的运动速率和断裂的活动性参数。研究表明,相对华南块体,研究区内各块体的欧拉角速度较小,且都为顺时针运动,... 详细信息

对华北地区1999以来的GPS观测数据进行处理,得到统一的GPS速度场。建立华北地区块体-位错模型,利用模拟退火方法,反演主要块体的运动速率和断裂的活动性参数。研究表明,相对华南块体,研究区内各块体的欧拉角速度较小,且都为顺时针运动,断裂活动性相对较弱。整体上张家口-蓬莱构造带处于左旋运动,运动速率约为1 mm/a,西段和东段表现出不同的性质,闭锁深度分别为40 km和30 km。山西断裂带具有一定程度的右旋走滑,走滑速率约为1 mm/a,断裂锁定深度为30 km。郯庐断裂带表现为右旋走滑,走滑速率在1 mm/a左右,断裂锁定深度为40 km。

关键词：活动块体位错 GPS 断裂活动

GPS高频数据处理方法及其在地震学中的应用研究进展

在线全文

学校读者我要写书评

暂无评论

国际地震动态 2007年第7期28卷 26-31页

作者：孟国杰任金卫金红林李鹏中国地震局地震预测研究所北京100036

本文简要介绍了GPS高频观测数据处理方法的特征,阐述了GPS高频观测数据在地震动态位移分析、震源破裂反演方面的应用研究进展。并对今后的发展趋势提出了自己的看法,认为在我国及时开展GPS高频数据处理方法和相关的应用研究是十分必要的。

关键词： GPS 高频观测数据处理地震动态位移

基于高斯距离加权格网法研究华北地区地壳形变特征

在线全文

学校读者我要写书评

暂无评论

大地测量与地球动力学 2015年第1期35卷 7-12页

作者：吴伟伟孟国杰苏小宁伍吉仓胡新康金红林中国地震局地震预测研究所北京市复兴路63号100036 同济大学测绘与地理信息学院上海市四平路1239号200092 中国地震局第一监测中心天津市河东区耐火路7号300180

分析了高斯距离加权格网法计算应变率的原理和特征,研制了相应的计算程序,并用于华北地区现今地壳应变特征研究。基于华北地区1999-2009年的GPS观测结果,研究了确定高斯平滑半径的原则和方法,并给出华北地区地壳形变多个应变率物理量的... 详细信息

分析了高斯距离加权格网法计算应变率的原理和特征,研制了相应的计算程序,并用于华北地区现今地壳应变特征研究。基于华北地区1999-2009年的GPS观测结果,研究了确定高斯平滑半径的原则和方法,并给出华北地区地壳形变多个应变率物理量的分布。结果表明,基于150km高斯平滑半径计算水平速度梯度能够较好地分辨华北地区的应变率空间变化特征,首都圈地区地壳以张渤带上的左旋剪切为主,其中唐山-秦皇岛地区同时存在南北向的拉张变形;山西带整体表现为沿断裂的右旋剪切变形,同时兼具＂南挤北张＂特性;郯庐断裂带整体形变特征不显著,在南北两端局部区域存在较小的剪切形变;鄂尔多斯块体内部比较稳定,北缘以拉张和左旋剪切变形为主,西缘表现为左旋剪切以及EW向的挤压特征,南缘的秦岭块体南北两侧分别具有左旋剪切和右旋剪切的特性,东西两侧分别表现为正断拉张与逆断挤压特征。

关键词：华北地区 GPS 高斯加权主应变率剪切应变率

Improved Particle Filter for Non-Gaussian Forecasting-aided State Estimation

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2023年第4期11卷 1075-1085页

作者： Lyuzerui Yuan Jie Gu honglin Wen Zhijian jin School of Electronic Information and Electrical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Gaussian assumptions of non-Gaussian noises hinder the improvement of state estimation *** this paper,an asymmetric generalized Gaussian distribution(AGGD),as a unified representation of various unimodal distributions,is applied to formulate the non-Gaussian forecasting-aided state estimation *** address the problem,an improved particle filter is proposed,which integrates a near-optimal AGGD proposal function and an AGGD sampling method into the typical particle *** AGGD proposal function can approximate the target distribution of state variables to greatly alleviate particle degeneracy and promote precise estimation,through considering both state transitions and latest *** rapid particle generation from the AGGD proposal function,an efficient inverse cumulative distribution function(CDF)sampling method is employed based on the derived approximation of inverse CDF of *** simulations are carried out on a modified balanced IEEE 123-bus test *** results validate that the proposed method outperforms other popular state estimation methods in terms of accuracy and robustness,whether in Gaussian,non-Gaussian,or abnormal measurement errors.

关键词： State estimation particle filter asymmetric generalized Gaussian distribution non-Gaussian noise

Optimal Network Partition and Edge Server Placement for Distributed State Estimation

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2022年第6期10卷 1637-1647页

作者： Lyuzerui Yuan Jie Gu jinghuan Ma honglin Wen Zhijian jin School of Electronic Information and Electrical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

This paper investigates network partition and edge server placement problem to exploit the benefit of edge computing for distributed state estimation.A constrained many-objective optimization problem is formulated to minimize the cost of edge server deployment,operation,and maintenance,avoid the difference in the partition sizes,reduce the level of coupling between connected partitions,and maximize the inner cohesion of each *** of edge server are constrained against underload and *** efficiently solve the problem,an improved non-dominated sorting genetic algorithm III(NSGA-III)is developed,with a specifically designed directed mutation operator based on topological characteristics of the partitions to accelerate *** study validates that the proposed formulations effectively characterize the practical concerns and reveal their trade-offs,and the improved algorithm outperforms existing representative ones for large-scale networks in converging to a near-optimal *** optimized result contributes significantly to real-time distributed state estimation.

关键词： Network partition edge server placement distributed state estimation edge computing non-dominated sorting genetic algorithm(NSGA)

Synthesis of ZnO by Chemical Bath Deposition in the Presence of Bacterial Cellulose

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2014年第4期27卷 656-662页

作者： Guangyao Xiong honglin Luo jing Zhang Jun jin Yizao Wan School of Mechanical and Electrical Engineering East China Jiaotong University Tianjin Key Laboratory of Composite and Functional Materials School of Materials Science and EngineeringTianjin University

The control of the morphology of zinc oxide（ZnO） crystals is very important in science and *** article reports the influence of bacterial cellulose（BC） on the morphology of ZnO prepared by chemical bath *** nanostructures synthesized with and without adding BC to the aqueous solution of zinc acetate and ammonia were characterized by scanning electron microscopy,transmission electron microscopy,and X-ray *** results reveal that the presence of BC in the aqueous solution changes the morphology from spindle to flower,which is ascribed to the interactions between –OH on BC nanofibers and Zn2？in the *** addition,optical property of the two ZnO nanostructures was compared.

关键词： Zinc oxide Optical property Morphology

Pre-earthquake ionospheric anomalies using ground-based GPS observations

在线全文

学校读者我要写书评

暂无评论

Pre-earthquake ionospheric anomalies using ground-based GPS ...

Fragmental Weight-Conservation Combining Scheme for Statistical Signal Transmissions under Fast Time-Varying Channels

The 19th International Workshop on Electromagnetic Induction in the Earth

作者： MENG Guojie~1 WANG Min~(1,2) MA Xinxin~3 SUO Yucheng~4 jin honglin~1 1 Institute of Earthquake Science,China Earthquake Administration,Beijing,China 2 Beijing National Observatory of Space Environment,Institute of Geology and Geophysics,Chinese Academy of Sciences 3 Chengdu University of Technology,Chengdu,China 4 The 22~(nd) Research Institute of China Electronics Technology Group Corporation

Based on the single layer ionosphere model,we have processed the continuous GPS data from a network of 25 ground-based receivers of the GPS in China and obtained the time series of variations of ionospheric total electron content (TEC).We have studied the TEC anomalies of 12 earthquakes (M≥6.0) which occurred in Chinese mainland during *** results show that the TEC values above the GPS stations located 700 km away from the epicenter have no obvious anomalies before and after earthquakes,andΔTEC variation is within 0.3 *** are 6 times ionospheric anomalies within 9 earthquakes that the distance between the epicenter and GPS station (DEG) is less than 700 *** anomalies appear mainly 1-5 days before earthquakes,and TEC anomalies are proportion to *** a few earthquakes,TEC values were increased *** research results show that it is possible to identify pre-earthquakes ionospheric anomalies from continuous GPS observation data.

关键词： Pre-earthquake anomaly Ionospheric precursor GPS total electron content (TEC)

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

China Communications 2020年第1期17卷 118-128页

作者： Xingwei Wang Ting Zhou Tianheng Xu Songlin Feng honglin Hu Yanliang jin School of Communication and Information Engineering Shanghai UniversityShanghai 200444China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201210China

Statistical Signal Transmission(SST)is a technique based on orthogonal frequency-division multiplexing(OFDM)and adopts cyclostationary features,which can transmit extra information without additional ***,the more complicated environment in 5G communication systems,especially the fast time-varying scenarios,will dramatically degrade the performance of the *** this paper,we propose a fragmental weight-conservation combining(FWCC)scheme for SST,to overcome its performance degradation under fast time-varying *** proposed FWCC scheme consists of three phases:1、incise the received OFDM stream into pieces;2、endue different weights for fine and contaminated pieces,respectively;3、combine cyclic autocorrelation function energies of all the pieces;and 4、compute the final feature and demodulate data of *** these procedures above,the detection accuracy of SST will be theoretically refined under fast time-varying *** an inference is confirmed through numerical results in this *** is demonstrated that the BER performance of proposed scheme outperforms that of the original scheme both in ideal channel estimation conditions and in imperfect channel estimation *** addition,we also find the experiential optimal weight distribution strategy for the proposed FWCC scheme,which facilitates practical applications.

关键词： Cyclostationary features statistical signal transmission(SST) weight conservation time-varying channels