This paper proposes a novel unmanned aerial vehicle(UAV)-based illegal radio station(IRS) localization scheme, where the transmit power of the IRS, the channel model and the noise model are unknown to the UAV. A direc...This paper proposes a novel unmanned aerial vehicle(UAV)-based illegal radio station(IRS) localization scheme, where the transmit power of the IRS, the channel model and the noise model are unknown to the UAV. A direction-aware Q-learning algorithm is developed to process received signal strength(RSS) values collected by a directional antenna, as well as directions corresponding to the RSS values. This algorithm determines the direction the UAV flies towards and thereby finds the IRS. The proposed scheme is compared to two baseline schemes. One baseline locates the IRS by a UAV equipped with an omnidirectional antenna, where conventional Q-learning is exploited to process the measured RSS and determine the UAV's trajectory. The other baseline locates the IRS by a directional-antenna UAV, where the UAV flies towards the direction with respect to the maximum RSS value. Numerical results show that, especially for a low receive SNR, the proposed scheme can outperform the two baselines in terms of the localization efficiency, providing a smoother trajectory for the UAV.展开更多
Guangdong Province is one of the provinces in China with the best modern agricultural industry and the highest production efficiency.While Jiangmen City,one of the agriculture-based cities in Guangdong Province,has ma...Guangdong Province is one of the provinces in China with the best modern agricultural industry and the highest production efficiency.While Jiangmen City,one of the agriculture-based cities in Guangdong Province,has made active exploration in building a modern agricultural system.China has established cooperation with the four largest agricultural research institutes in China to offer technical support for the development of modern agriculture.In this paper,the status quo and existing problems of agricultural development in Jiangmen,Guangdong are briefly introduced.Then,the cooperation status and prospect of local government with the research institutes are discussed.Finally some suggestions are given on the agricultural development pattern in Jiangmen City.展开更多
We present the results of two ground-based radio-echo-sounding（RES） and GPS surveys performed in the vicinity of new Chinese Taishan station,Princess Elizabeth Land,East Antarctica,obtained in two austral summers du...We present the results of two ground-based radio-echo-sounding（RES） and GPS surveys performed in the vicinity of new Chinese Taishan station,Princess Elizabeth Land,East Antarctica,obtained in two austral summers during CHINARE 21（2004/2005） and CHINARE 29（2012/2013）.The radar surveys measured ice thickness and internal layers using 60- and 150-MHz radar systems,and GPS measurements showed smooth surface slopes around the station with altitudes of 2607-2636 m above sea level（a.s.l.）.Radar profiles indicate an average ice thickness of 1900 m,with a maximum of 1949 m and a minimum of 1856 m,within a square area measuring approximately 2 km × 2 km in the vicinity of the station.The ice thickness beneath the station site is 1870 m.The subglacial landscape beneath the station is quiet sharp and ranges from 662 to 770 m a.s.l.,revealing part of a mountainous topography.The ice volume in the grid is estimated to be 7.6 km^3.Along a 60-MHz radar profile with a length of 17.6 km at the region covering the station site,some disturbed internal layers are identified and traced;the geometry of internal layers within the englacial stratigraphy may imply a complex depositional process in the area.展开更多
针对传统杆状天线在现代化战争应用场景中存在的带宽窄、质地硬以及隐蔽性与便携性较差等问题,提出了一种基于柔性介质材料的可穿戴式天线,该天线采用平面单极子天线的形式,极大地降低天线的剖面。借助电磁仿真软件CST Studio Suite 202...针对传统杆状天线在现代化战争应用场景中存在的带宽窄、质地硬以及隐蔽性与便携性较差等问题,提出了一种基于柔性介质材料的可穿戴式天线,该天线采用平面单极子天线的形式,极大地降低天线的剖面。借助电磁仿真软件CST Studio Suite 2023进行仿真分析,该天线尺寸为270 mm×270 mm×1.1 mm,重量仅有120 g,包含0.37~1.8 GHz的实测宽带频段,在人体加载影响下,实测频段范围超过0.3~1.8 GHz。给出了反射系数S_(11)、辐射方向图的结果,分析了人体对天线的影响,结合通信电台开展实物对比测试。仿真与实测表明,可穿戴式天线在士兵手持电台中具有一定的应用前景。展开更多
基金supported by China NSF Grants(61631020)Fundamental Research Funds for the Central Universities(NP2018103,NE2017103,NC2017003)
文摘This paper proposes a novel unmanned aerial vehicle(UAV)-based illegal radio station(IRS) localization scheme, where the transmit power of the IRS, the channel model and the noise model are unknown to the UAV. A direction-aware Q-learning algorithm is developed to process received signal strength(RSS) values collected by a directional antenna, as well as directions corresponding to the RSS values. This algorithm determines the direction the UAV flies towards and thereby finds the IRS. The proposed scheme is compared to two baseline schemes. One baseline locates the IRS by a UAV equipped with an omnidirectional antenna, where conventional Q-learning is exploited to process the measured RSS and determine the UAV's trajectory. The other baseline locates the IRS by a directional-antenna UAV, where the UAV flies towards the direction with respect to the maximum RSS value. Numerical results show that, especially for a low receive SNR, the proposed scheme can outperform the two baselines in terms of the localization efficiency, providing a smoother trajectory for the UAV.
基金Supported by the Special Fund for the Construction of Modern Agricultural Technical System(CARS-12-gdqxd)the Special Foundation for the Basic Scientific Research of Central Public Welfare Institute(1630032013033)
文摘Guangdong Province is one of the provinces in China with the best modern agricultural industry and the highest production efficiency.While Jiangmen City,one of the agriculture-based cities in Guangdong Province,has made active exploration in building a modern agricultural system.China has established cooperation with the four largest agricultural research institutes in China to offer technical support for the development of modern agriculture.In this paper,the status quo and existing problems of agricultural development in Jiangmen,Guangdong are briefly introduced.Then,the cooperation status and prospect of local government with the research institutes are discussed.Finally some suggestions are given on the agricultural development pattern in Jiangmen City.
基金financially supported by the National Natural Science Foundation of China(Grant No.41376192,40906101)the National Basic Research Program of China(973 Program)(Grant No.2013CBA01804 and 2012CB957702)+2 种基金the Foreign Cooperation Support Program of Chinese Arctic and Antarctic Administration,SOA,China(Grand No.IC201214)the Natural Science Foundation of Shanghai,China(Grand No.13ZR1445300)the Chinese Polar Environment Comprehensive Investigation&Assessment Programmes(CHINARE2014-01-01)
文摘We present the results of two ground-based radio-echo-sounding（RES） and GPS surveys performed in the vicinity of new Chinese Taishan station,Princess Elizabeth Land,East Antarctica,obtained in two austral summers during CHINARE 21（2004/2005） and CHINARE 29（2012/2013）.The radar surveys measured ice thickness and internal layers using 60- and 150-MHz radar systems,and GPS measurements showed smooth surface slopes around the station with altitudes of 2607-2636 m above sea level（a.s.l.）.Radar profiles indicate an average ice thickness of 1900 m,with a maximum of 1949 m and a minimum of 1856 m,within a square area measuring approximately 2 km × 2 km in the vicinity of the station.The ice thickness beneath the station site is 1870 m.The subglacial landscape beneath the station is quiet sharp and ranges from 662 to 770 m a.s.l.,revealing part of a mountainous topography.The ice volume in the grid is estimated to be 7.6 km^3.Along a 60-MHz radar profile with a length of 17.6 km at the region covering the station site,some disturbed internal layers are identified and traced;the geometry of internal layers within the englacial stratigraphy may imply a complex depositional process in the area.
文摘针对传统杆状天线在现代化战争应用场景中存在的带宽窄、质地硬以及隐蔽性与便携性较差等问题,提出了一种基于柔性介质材料的可穿戴式天线,该天线采用平面单极子天线的形式,极大地降低天线的剖面。借助电磁仿真软件CST Studio Suite 2023进行仿真分析,该天线尺寸为270 mm×270 mm×1.1 mm,重量仅有120 g,包含0.37~1.8 GHz的实测宽带频段,在人体加载影响下,实测频段范围超过0.3~1.8 GHz。给出了反射系数S_(11)、辐射方向图的结果,分析了人体对天线的影响,结合通信电台开展实物对比测试。仿真与实测表明,可穿戴式天线在士兵手持电台中具有一定的应用前景。
