中央控制系统(CCS,Central Control System)是卫星电气地面支持设备(EGSE,Electrical GroundSupport Equipment)的核心,其性能的优劣对卫星的地面测试有重要影响.针对设计的CCS提出了影响其性能的主要技术指标——网络连接响应时间、测...中央控制系统(CCS,Central Control System)是卫星电气地面支持设备(EGSE,Electrical GroundSupport Equipment)的核心,其性能的优劣对卫星的地面测试有重要影响.针对设计的CCS提出了影响其性能的主要技术指标——网络连接响应时间、测试序列执行能力和数据处理能力,提出了CCS性能测试方案,设计了性能测试用例,进行了CCS性能测试并给出了测试结论.结果表明,该CCS具有较好的性能,满足当前卫星地面测试的要求.展开更多
This study used time-series of global inventory modeling and mapping studies （GIMMS） normalized difference vegetation index （NDVI） datasets at a spatial resolution of 8 km and 15-d interval to investigate the spat...This study used time-series of global inventory modeling and mapping studies （GIMMS） normalized difference vegetation index （NDVI） datasets at a spatial resolution of 8 km and 15-d interval to investigate the spatial patterns of cropland phenology in China. A smoothing algorithm based on an asymmetric Gaussian function was first performed on NDVI dataset to minimize the effects of anomalous values caused by atmospheric haze and cloud contamination. Subsequent processing for identifying cropping systems and extracting phenological parameters, the starting date of growing season （SGS） and the ending date of growing season （EGS） was based on the smoothed NVDI time-series data. The results showed that the cropping systems in China became complex as moving from north to south of China. Under these cropping systems, the SGS and EGS for the first growing season varied largely over space, and those regions with multiple cropping systems generally presented a significant advanced SGS and EGS than the regions with single cropping patterns. On the contrary, the phenological events of the second growing season including both the SGS and EGS showed little difference between regions. The spatial patterns of cropping systems and phenology in Chinese cropland were highly related to the geophysical environmental factors. Several anthropogenic factors, such as crop variety, cultivation levels, irrigation, and fertilizers, could profoundly influence crop phenological status. How to discriminate the impacts of biophysical forces and anthropogenic drivers on phenological events of cultivation remains a great challenge for further studies.展开更多
文摘中央控制系统(CCS,Central Control System)是卫星电气地面支持设备(EGSE,Electrical GroundSupport Equipment)的核心,其性能的优劣对卫星的地面测试有重要影响.针对设计的CCS提出了影响其性能的主要技术指标——网络连接响应时间、测试序列执行能力和数据处理能力,提出了CCS性能测试方案,设计了性能测试用例,进行了CCS性能测试并给出了测试结论.结果表明,该CCS具有较好的性能,满足当前卫星地面测试的要求.
基金supported by the National Natural Science Foundation of China (40930101,40971218)the 948 Program,Ministry of Agriculture of China (2009-Z31)the Foundation for National Non-Profit Scientific Institution,Ministry of Finance of China (IARRP-2010-2)
文摘This study used time-series of global inventory modeling and mapping studies （GIMMS） normalized difference vegetation index （NDVI） datasets at a spatial resolution of 8 km and 15-d interval to investigate the spatial patterns of cropland phenology in China. A smoothing algorithm based on an asymmetric Gaussian function was first performed on NDVI dataset to minimize the effects of anomalous values caused by atmospheric haze and cloud contamination. Subsequent processing for identifying cropping systems and extracting phenological parameters, the starting date of growing season （SGS） and the ending date of growing season （EGS） was based on the smoothed NVDI time-series data. The results showed that the cropping systems in China became complex as moving from north to south of China. Under these cropping systems, the SGS and EGS for the first growing season varied largely over space, and those regions with multiple cropping systems generally presented a significant advanced SGS and EGS than the regions with single cropping patterns. On the contrary, the phenological events of the second growing season including both the SGS and EGS showed little difference between regions. The spatial patterns of cropping systems and phenology in Chinese cropland were highly related to the geophysical environmental factors. Several anthropogenic factors, such as crop variety, cultivation levels, irrigation, and fertilizers, could profoundly influence crop phenological status. How to discriminate the impacts of biophysical forces and anthropogenic drivers on phenological events of cultivation remains a great challenge for further studies.
