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新技术在北极星天文方位角测量中的应用 被引量:2
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作者 赵珞成 熊瑛 《测绘信息与工程》 2003年第3期37-39,共3页
使用GPS接收机的UTC作为北极星天文方位角测量的时间比对的标准时间 ,利用推估UT1与UTC的差值 ,将时间归算到UT1的方法 ,可满足各等级天文方位角测量的要求 ,现场计算零点恒星时和北极星坐标的精度满足北极星天文方位角测量的要求 ,实... 使用GPS接收机的UTC作为北极星天文方位角测量的时间比对的标准时间 ,利用推估UT1与UTC的差值 ,将时间归算到UT1的方法 ,可满足各等级天文方位角测量的要求 ,现场计算零点恒星时和北极星坐标的精度满足北极星天文方位角测量的要求 ,实现了现场评估测量精度。 展开更多
关键词 北极星 天文方位角测量 GPS接收机 UTC 时间归算 全球定位系统
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Rainfall and Obtaining Information Regarding Earthquake Development Processes from Groundwater Level
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作者 Li Yong Fang Wei Ma Li 《Earthquake Research in China》 2008年第1期52-61,共10页
Many factors can cause changes of groundwater level,such as the development process of an earthquake,rainfall,solid earth tides etc.Among these we are interested in information regarding earthquake development process... Many factors can cause changes of groundwater level,such as the development process of an earthquake,rainfall,solid earth tides etc.Among these we are interested in information regarding earthquake development processes.Eliminating the influence of various disturbance factors is an effective way to obtain seismic development process information contained in the groundwater level.This paper provides two different ways to remove the rainfall effect,and compares the two methods by means of correlation analysis.Furthermore,based on these a logistic regression model is established to describe the seismicity level. 展开更多
关键词 SEISMICITY Groundwater level Time series Logistic regression models
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Modified Recursive Least Squares Algorithm with Variable Parameters and Resetting for Time-Varying System
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作者 薛云灿 钱积新 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2002年第3期298-303,共6页
Based on the idea of the set-membership identification, a modified recursive least squares algorithm with variable gain, variable forgetting factor and resetting is presented. The concept of the error tolerance level ... Based on the idea of the set-membership identification, a modified recursive least squares algorithm with variable gain, variable forgetting factor and resetting is presented. The concept of the error tolerance level is proposed. The selection criteria of the error tolerance level are also given according to the min-max principle. The algorithm is particularly suitable for tracing time-varying systems and is similar in computational complexity to the standard recursive least squares algorithm. The superior performance of the algorithm is verified ma simulation studies on a dynamic fermentation process. 展开更多
关键词 least-squares algorithm dynamic fermentation process parameter estimation IDENTIFICATION
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