Focused on the non-statlonarity and real-time analysis of signal in flutter test with progression variable speed （FTPVS）, a new method of recursive time-frequency analysis is presented. The time-varying system is tr...Focused on the non-statlonarity and real-time analysis of signal in flutter test with progression variable speed （FTPVS）, a new method of recursive time-frequency analysis is presented. The time-varying system is tracked on-line by building a time-varying parameter model, and then the relevant parameter spectrum can be obtained. The feasibility and advantages of the method are examined by digital simulation. The results of FTPVS at low-speed wind-tunnel promise the engineering application perspective of the method.展开更多
A method is proposed to fuse the velocity data of the global navigation satellite system(GNSS) and leveling height via combined adjustment with constraints. First, stable GNSS-leveling points are uniformly selected, a...A method is proposed to fuse the velocity data of the global navigation satellite system(GNSS) and leveling height via combined adjustment with constraints. First, stable GNSS-leveling points are uniformly selected, and the constraints of the geodetic height change velocity and normal height change velocity are given. Then, the GNSS vertical velocities and leveling height difference are used as observations of combined adjustment, and robust least-squares estimation are used to estimate the velocities of the unknown points. Finally, a vertical movement model is established with the GNSS vertical velocities and leveling vertical velocities obtained via combined adjustment. Data from the second-order leveling network and GNSS control points in Shandong Province are taken as test data, and eight calculation schemes are used for discussion. One of the schemes, the bifactor robust combined adjustment method based on variance component estimation with two kinds of vertical velocity constraints achieves the optimal results. The method applied in the scheme can be recommended for data fusion of GNSS and leveling, further improving the reliability of vertical crustal movement in Shandong Province.展开更多
The quality of altimeter data and ocean tide model is critical to the recovery of coastal gravity anomalies. In this contribution, three retracking methods (threshold, improved threshold and Beta-5) are investigated w...The quality of altimeter data and ocean tide model is critical to the recovery of coastal gravity anomalies. In this contribution, three retracking methods (threshold, improved threshold and Beta-5) are investigated with the aim of improving the altimeter data over a shallow water area. Comparison indicates that the improved threshold is the best retracking method over China Sea. Two ocean tide models, NAO99b and CSR4.0, are analyzed. Results show that different tide models used in the processing of altimeter data may result in differences more than 10 mGal in recovered coastal gravity anomalies. Also, NAO99b is more suitable than CSR4.0 over the shallow water area of China Sea. Finally, gravity anomalies over China Sea are calculated from retracked Geosat/GM and ERS-1/GM data by least squares collocation. Comparison with shipborne gravimetry data demonstrates that gravity anomalies from retracked data are significantly superior to those from non-retracked data. Our results have the same order as the other two altimeter-derived gravity models: Sandwell&Smith(V16) and DNSC08.展开更多
The contribution presents the representative research progress on global static gravity field modeling,regional geoid/quasigeoid determination,vertical datum study,as well as the theory,algorithm and software for grav...The contribution presents the representative research progress on global static gravity field modeling,regional geoid/quasigeoid determination,vertical datum study,as well as the theory,algorithm and software for gravity field study in China from 2019 to 2023,which are the highlights of the chapter 6“Progress in Earth Gravity Model and Vertical Datum”in the“2019—2023 China National Report on Geodesy”that submitted to the International Association of Geodesy(IAG).In addition,suggestions are proposed to promote the research in the fields of earth gravity field,geoid/quasigeoid and vertical datumin China according to trends of international geodesy and related disciplines.展开更多
We have investigated the Nu Calm Transcutaneous Vagus Nerve Stimulation device of the NuCalm Solace Lifesciences founding that it gives a multifractal output. A diminishing fractal/multifractal HRV is consistently rep...We have investigated the Nu Calm Transcutaneous Vagus Nerve Stimulation device of the NuCalm Solace Lifesciences founding that it gives a multifractal output. A diminishing fractal/multifractal HRV is consistently reported in literature as related to a serious Autonomic Nervous System (ANS) dysfunction that of course we observe in several psychological and psychiatric disorders. Therefore, we suggest the investigators to apply such a device in subjects affected from anxiety, depression and stress using the method of inducing tVNS stimulation.展开更多
By using precise leveling data observed between 1985 and 2010 across the south section of the Longmenshan fault zone,and eliminating the coseismic displacements caused by the Wenchuan Ms 8.0 earthquake,the interseismi...By using precise leveling data observed between 1985 and 2010 across the south section of the Longmenshan fault zone,and eliminating the coseismic displacements caused by the Wenchuan Ms 8.0 earthquake,the interseismic vertical deformation field was obtained.The result shows that the Lushan region,located between the Shuangshi–Dachuan fault(front range of the Longmenshan fault) and the Xinkaidian fault(south section of the Dayi fault),is situated in the intersection zone of positive and negative vertical deformation gradient zones,indicating that this zone was locked within 25 years before the Lushan earthquake.Based on leveling data across the rupture zone surveyed between 2010 and 2013,and by eliminating the vertical deformation within 3 years before the earthquake,the coseismic vertical displacement was derived.The coseismic vertical displacement for the benchmark DD35,which is closest to the epicenter,is up to198.4 mm(with respect to MY165A).The coseismic displacement field revealed that the northwest region(hanging wall) moved upwards in comparison with the southeastern region(foot wall),suggesting that the seismogenic fault mainly underwent thrust faulting.By comparing the coseismic and interseismic vertical deformation fields,it was found that the mechanisms of this earthquake are consistent with the elastic rebound theory; the elastic strain energy(displacement deficit) accumulated before the Lushan earthquake was released during this quake.展开更多
文摘Focused on the non-statlonarity and real-time analysis of signal in flutter test with progression variable speed （FTPVS）, a new method of recursive time-frequency analysis is presented. The time-varying system is tracked on-line by building a time-varying parameter model, and then the relevant parameter spectrum can be obtained. The feasibility and advantages of the method are examined by digital simulation. The results of FTPVS at low-speed wind-tunnel promise the engineering application perspective of the method.
基金supported by the National Natural Science Foundation of China(41774004,41904040)the Technological Innovation of SHASG(SCK2020-11).
文摘A method is proposed to fuse the velocity data of the global navigation satellite system(GNSS) and leveling height via combined adjustment with constraints. First, stable GNSS-leveling points are uniformly selected, and the constraints of the geodetic height change velocity and normal height change velocity are given. Then, the GNSS vertical velocities and leveling height difference are used as observations of combined adjustment, and robust least-squares estimation are used to estimate the velocities of the unknown points. Finally, a vertical movement model is established with the GNSS vertical velocities and leveling vertical velocities obtained via combined adjustment. Data from the second-order leveling network and GNSS control points in Shandong Province are taken as test data, and eight calculation schemes are used for discussion. One of the schemes, the bifactor robust combined adjustment method based on variance component estimation with two kinds of vertical velocity constraints achieves the optimal results. The method applied in the scheme can be recommended for data fusion of GNSS and leveling, further improving the reliability of vertical crustal movement in Shandong Province.
基金Supported by the National Natural Science Foundation of China(No.40704003)the National 973 Program of China(No.2007CB714405)the Key Laboratory of Surveying and Mapping Technology on Island and Reef,State Bureau of Surveying and Mapping,China(No.2009B04)
文摘The quality of altimeter data and ocean tide model is critical to the recovery of coastal gravity anomalies. In this contribution, three retracking methods (threshold, improved threshold and Beta-5) are investigated with the aim of improving the altimeter data over a shallow water area. Comparison indicates that the improved threshold is the best retracking method over China Sea. Two ocean tide models, NAO99b and CSR4.0, are analyzed. Results show that different tide models used in the processing of altimeter data may result in differences more than 10 mGal in recovered coastal gravity anomalies. Also, NAO99b is more suitable than CSR4.0 over the shallow water area of China Sea. Finally, gravity anomalies over China Sea are calculated from retracked Geosat/GM and ERS-1/GM data by least squares collocation. Comparison with shipborne gravimetry data demonstrates that gravity anomalies from retracked data are significantly superior to those from non-retracked data. Our results have the same order as the other two altimeter-derived gravity models: Sandwell&Smith(V16) and DNSC08.
基金National Key R&D Program of China(Nos.2021YFB3900200,2021YFB3900203)。
文摘The contribution presents the representative research progress on global static gravity field modeling,regional geoid/quasigeoid determination,vertical datum study,as well as the theory,algorithm and software for gravity field study in China from 2019 to 2023,which are the highlights of the chapter 6“Progress in Earth Gravity Model and Vertical Datum”in the“2019—2023 China National Report on Geodesy”that submitted to the International Association of Geodesy(IAG).In addition,suggestions are proposed to promote the research in the fields of earth gravity field,geoid/quasigeoid and vertical datumin China according to trends of international geodesy and related disciplines.
文摘We have investigated the Nu Calm Transcutaneous Vagus Nerve Stimulation device of the NuCalm Solace Lifesciences founding that it gives a multifractal output. A diminishing fractal/multifractal HRV is consistently reported in literature as related to a serious Autonomic Nervous System (ANS) dysfunction that of course we observe in several psychological and psychiatric disorders. Therefore, we suggest the investigators to apply such a device in subjects affected from anxiety, depression and stress using the method of inducing tVNS stimulation.
基金supported by National Special Fund for Earthquake Scientific Research in Public Interest(201408014,201208009)the National Natural Science Foundation of China(41174083)
文摘By using precise leveling data observed between 1985 and 2010 across the south section of the Longmenshan fault zone,and eliminating the coseismic displacements caused by the Wenchuan Ms 8.0 earthquake,the interseismic vertical deformation field was obtained.The result shows that the Lushan region,located between the Shuangshi–Dachuan fault(front range of the Longmenshan fault) and the Xinkaidian fault(south section of the Dayi fault),is situated in the intersection zone of positive and negative vertical deformation gradient zones,indicating that this zone was locked within 25 years before the Lushan earthquake.Based on leveling data across the rupture zone surveyed between 2010 and 2013,and by eliminating the vertical deformation within 3 years before the earthquake,the coseismic vertical displacement was derived.The coseismic vertical displacement for the benchmark DD35,which is closest to the epicenter,is up to198.4 mm(with respect to MY165A).The coseismic displacement field revealed that the northwest region(hanging wall) moved upwards in comparison with the southeastern region(foot wall),suggesting that the seismogenic fault mainly underwent thrust faulting.By comparing the coseismic and interseismic vertical deformation fields,it was found that the mechanisms of this earthquake are consistent with the elastic rebound theory; the elastic strain energy(displacement deficit) accumulated before the Lushan earthquake was released during this quake.
