Natural disaster or large-scale unexpected events easily make the terrestrial network overloaded,paralyzed, or totally destroyed. It is highly demanded to build an emergency network which can be deployed rapidly, offe...Natural disaster or large-scale unexpected events easily make the terrestrial network overloaded,paralyzed, or totally destroyed. It is highly demanded to build an emergency network which can be deployed rapidly, offer high data rate and wide coverage. The emergence of aerial platforms especially the low altitude platforms(LAPs) indicates a stable and reliable direction for the development of emergency network. Hybrid satellite-aerial-terrestrial(HSAT) networks have the ability to provide effective services rather than traditional infrastructures during the emergency situation. In this paper, the aerial platforms and the HSAT networks are surveyed and the key technologies are discussed from several aspects. The challenges of the HSAT networks are also outlined finally.展开更多
In this study,the authors introduce a new bogus data assimilation method based on the dimension-reduced projection 4-DVar,which can resolve the cost function directly in low-dimensional space.The authors also try a ne...In this study,the authors introduce a new bogus data assimilation method based on the dimension-reduced projection 4-DVar,which can resolve the cost function directly in low-dimensional space.The authors also try a new method to improve the quality of samples,which are the base of dimension-reduced space projection bogus data assimilation (DRP-BDA).By running a number of numerical weather models with different model parameterization combinations on the typhoon Sinlaku,the authors obtained two groups of samples with different spreads and similarities.After DRP-BDA,the results show that,compared with the control runs,the simulated typhoon center pressure can be deepened by more than 20 hPa to 30 hPa and that the intensity can last as long as 60 hours.The mean track error is improved after DRP-BDA,and the structure of the typhoon is also improved.The wind near the typhoon center is enhanced dramatically,while the warm core is moderate.展开更多
Based on the analysis of different requirements of energy management center construction and the data acquisition of various industries in wide area network, as well as the practices of real-lime online system, the pa...Based on the analysis of different requirements of energy management center construction and the data acquisition of various industries in wide area network, as well as the practices of real-lime online system, the paper puts forward the construction scheme of regional energy management center （REMC） which can achieve real time online monitoring of organizations＇ energy consumption via data collection, and also proposes the design idea of energy data acquisition based on national standards.展开更多
The temporal and spatial distribution characteristics of earthquakes in the Ordos block are studied by using historical earthquake data,instrument data of the regional seismic network around the Ordos block and the hi...The temporal and spatial distribution characteristics of earthquakes in the Ordos block are studied by using historical earthquake data,instrument data of the regional seismic network around the Ordos block and the historical felt earthquake data,and the relationship between seismicity in the Ordos block and seismicity around the Ordos block is discussed. The result shows that the Ordos block is a typical moderate-strong earthquake active region where many M_S≥5.0 destructive earthquakes have occurred. The temporal and spatial distribution of earthquakes in the Ordos block is asymmetrical. The temporal distribution of earthquakes shows a periodic characteristic and the activity of earthquakes in the southeastern Ordos block is higher than in the northwest Ordos block. The M_S≥5.0 moderate size earthquakes in the Ordos block are controlled by the M_S≥6.0 earthquake around the Ordos block.展开更多
We present two efficient approaches,namely the epoch-differenced(ED) and satellite-and epoch-differenced(SDED) approaches,for the estimation of IFCBs of the two Block IIF satellites.For the analysis,data from 18 stati...We present two efficient approaches,namely the epoch-differenced(ED) and satellite-and epoch-differenced(SDED) approaches,for the estimation of IFCBs of the two Block IIF satellites.For the analysis,data from 18 stations from the IGS network spanning 96 d is processed.Results show that the IFCBs of PRN25 and PRN01 exhibit periodical signal of one orbit revolution with a magnitude up to 18 cm.The periodical variation of the IFCBs is modeled by a sinusoidal function of the included angle between the sun,earth and the satellite.The presented model enables a consistent use of L1/L2 clock products in L1/L5-based positioning.The algorithm is incorporated into the MGPSS software at SHAO(Shanghai Astronomical Observatory,Chinese Academy of Sciences) and is used to monitor the IFCB variation in near real-time.展开更多
基金supported by the National 863 Project under Grant No.2015AA015701National Nature Science Foundation of China under Grant No. 61421061
文摘Natural disaster or large-scale unexpected events easily make the terrestrial network overloaded,paralyzed, or totally destroyed. It is highly demanded to build an emergency network which can be deployed rapidly, offer high data rate and wide coverage. The emergence of aerial platforms especially the low altitude platforms(LAPs) indicates a stable and reliable direction for the development of emergency network. Hybrid satellite-aerial-terrestrial(HSAT) networks have the ability to provide effective services rather than traditional infrastructures during the emergency situation. In this paper, the aerial platforms and the HSAT networks are surveyed and the key technologies are discussed from several aspects. The challenges of the HSAT networks are also outlined finally.
基金the Ministry of Finance of China and the China Meteorological Administration for the Special Project of Meteorological Sector (Grant No. GYHY(QX)200906009)the National Natural Science Foundation of China for the innovation group project (Grant No.40821092)
文摘In this study,the authors introduce a new bogus data assimilation method based on the dimension-reduced projection 4-DVar,which can resolve the cost function directly in low-dimensional space.The authors also try a new method to improve the quality of samples,which are the base of dimension-reduced space projection bogus data assimilation (DRP-BDA).By running a number of numerical weather models with different model parameterization combinations on the typhoon Sinlaku,the authors obtained two groups of samples with different spreads and similarities.After DRP-BDA,the results show that,compared with the control runs,the simulated typhoon center pressure can be deepened by more than 20 hPa to 30 hPa and that the intensity can last as long as 60 hours.The mean track error is improved after DRP-BDA,and the structure of the typhoon is also improved.The wind near the typhoon center is enhanced dramatically,while the warm core is moderate.
文摘Based on the analysis of different requirements of energy management center construction and the data acquisition of various industries in wide area network, as well as the practices of real-lime online system, the paper puts forward the construction scheme of regional energy management center （REMC） which can achieve real time online monitoring of organizations＇ energy consumption via data collection, and also proposes the design idea of energy data acquisition based on national standards.
基金funded by the project of"Study on the key techniques of strong earthquake risk zoning"under the National Science and Technology Support Program of China,Grant No.2006BAC13B01
文摘The temporal and spatial distribution characteristics of earthquakes in the Ordos block are studied by using historical earthquake data,instrument data of the regional seismic network around the Ordos block and the historical felt earthquake data,and the relationship between seismicity in the Ordos block and seismicity around the Ordos block is discussed. The result shows that the Ordos block is a typical moderate-strong earthquake active region where many M_S≥5.0 destructive earthquakes have occurred. The temporal and spatial distribution of earthquakes in the Ordos block is asymmetrical. The temporal distribution of earthquakes shows a periodic characteristic and the activity of earthquakes in the southeastern Ordos block is higher than in the northwest Ordos block. The M_S≥5.0 moderate size earthquakes in the Ordos block are controlled by the M_S≥6.0 earthquake around the Ordos block.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41204034,41174023 and 11173049)the Opening Project of Shanghai Key Laboratory of Space Navigation and Position Techniques (Grant No. Y224 353002)
文摘We present two efficient approaches,namely the epoch-differenced(ED) and satellite-and epoch-differenced(SDED) approaches,for the estimation of IFCBs of the two Block IIF satellites.For the analysis,data from 18 stations from the IGS network spanning 96 d is processed.Results show that the IFCBs of PRN25 and PRN01 exhibit periodical signal of one orbit revolution with a magnitude up to 18 cm.The periodical variation of the IFCBs is modeled by a sinusoidal function of the included angle between the sun,earth and the satellite.The presented model enables a consistent use of L1/L2 clock products in L1/L5-based positioning.The algorithm is incorporated into the MGPSS software at SHAO(Shanghai Astronomical Observatory,Chinese Academy of Sciences) and is used to monitor the IFCB variation in near real-time.
