This paper is a study of the quantitative evaluation on the cost-effectiveness of air defense surveillance radars. The composition of life cycle cost of the radar is analysed at first. Then the radar performance and e...This paper is a study of the quantitative evaluation on the cost-effectiveness of air defense surveillance radars. The composition of life cycle cost of the radar is analysed at first. Then the radar performance and effectiveness formulas are derived. By calculating the values of many radars' cost, performance and effectiveness, tendency curves are plotted. The application of cost-effectiveness calculation and the tendency curves in radar system analysis is discussed at last.展开更多
This survey was designed to assess the sanitation status of hospitals and the compliance of hospital staff to disinfection strategies within the past 11 years.A total of 199 provincial affiliated tertiary or secondary...This survey was designed to assess the sanitation status of hospitals and the compliance of hospital staff to disinfection strategies within the past 11 years.A total of 199 provincial affiliated tertiary or secondary public hospitals from 2007 to 2017 were investigated and seven critical categories,namely indoor air,work surface,hand hygiene,ultraviolet(UV)irradiation intensity,use of disinfectants,sterilization of medical items,and effects of steam sterilizer,were monitored.The average qualified rates were(94.74±3.54)%(810/855),(97.25±1.65)%(1876/1929),(87.57±4.60)%(2508/2864),(95.00±4.50)%(1196/1259),and(98.76±1.14)%(1599/1619)for indoor air,work surface,hand hygiene,UV irradiation intensity,and sterilization of medical items,respectively.In terms of other categories,few samples were not qualified:3/1575 for use of disinfectants and 1/243 for effects of steam sterilizer.The hospital disinfection monitoring and supervision program effectively improved the effectiveness of disinfection.Routine monitoring and supervision must be conducted to ensure a safe hospital treatment environment.展开更多
The primary technique used for air traffic surveillance is radar.However,nowadays,its role in surveillance is gradually being replaced by the recently adopted Automatic Dependent Surveillance-Broadcast(ADS-B).ADS-B of...The primary technique used for air traffic surveillance is radar.However,nowadays,its role in surveillance is gradually being replaced by the recently adopted Automatic Dependent Surveillance-Broadcast(ADS-B).ADS-B offers a higher accuracy,lower power consumption,and longer range than radar,thus providing more safety to aircraft.The coverage of terrestrial radar and ADS-B is confined to continental parts of the globe,leaving oceans and poles uncovered by real-time surveillance measures.This study presents an optimized Low-Earth Orbit(LEO)-based ADS-B constellation for global air traffic surveillance over intercontinental trans-oceanic flight routes.The optimization algorithm is based on performance evaluation parameters,i.e.,coverage time,satellite availability,and orbit stability(precession and perigee rotation),and communication analysis.The results indicate that the constellation provides ample coverage in the simulated global oceanic regions.The constellation is a feasible and cost-effective solution for global air supervision,which can supplement terrestrial ADS-B and radar systems.展开更多
At present, most of the passive radar system researches utilize FM radios, TV broadcasts, navigation satellites,etc. as illuminators. The transmitted signals are not specifically designed radar waveforms. In this work...At present, most of the passive radar system researches utilize FM radios, TV broadcasts, navigation satellites,etc. as illuminators. The transmitted signals are not specifically designed radar waveforms. In this work, the frequency agile, phased array air surveillance radar(ASR) is used as the illuminator of opportunity to detect the weak target. The phased array technology can help realize beam agility to track targets from different aspects simultaneously. The frequency agility technology is widely employed in radar system design to increase the ability of anti-jamming and increase the detection probability. While the frequency bandwidth of radar signals is usually wide and the range resolution is high, the range cell migration effect is obvious during the long time integration of non-cooperative bistatic radar. In this context, coherent integration methods are not applicable. In this work, a parametric non-coherent integration algorithm based on task de-interweaving is proposed. Numerical experiments verify that this is effective in weak target detection.展开更多
文摘This paper is a study of the quantitative evaluation on the cost-effectiveness of air defense surveillance radars. The composition of life cycle cost of the radar is analysed at first. Then the radar performance and effectiveness formulas are derived. By calculating the values of many radars' cost, performance and effectiveness, tendency curves are plotted. The application of cost-effectiveness calculation and the tendency curves in radar system analysis is discussed at last.
文摘This survey was designed to assess the sanitation status of hospitals and the compliance of hospital staff to disinfection strategies within the past 11 years.A total of 199 provincial affiliated tertiary or secondary public hospitals from 2007 to 2017 were investigated and seven critical categories,namely indoor air,work surface,hand hygiene,ultraviolet(UV)irradiation intensity,use of disinfectants,sterilization of medical items,and effects of steam sterilizer,were monitored.The average qualified rates were(94.74±3.54)%(810/855),(97.25±1.65)%(1876/1929),(87.57±4.60)%(2508/2864),(95.00±4.50)%(1196/1259),and(98.76±1.14)%(1599/1619)for indoor air,work surface,hand hygiene,UV irradiation intensity,and sterilization of medical items,respectively.In terms of other categories,few samples were not qualified:3/1575 for use of disinfectants and 1/243 for effects of steam sterilizer.The hospital disinfection monitoring and supervision program effectively improved the effectiveness of disinfection.Routine monitoring and supervision must be conducted to ensure a safe hospital treatment environment.
文摘The primary technique used for air traffic surveillance is radar.However,nowadays,its role in surveillance is gradually being replaced by the recently adopted Automatic Dependent Surveillance-Broadcast(ADS-B).ADS-B offers a higher accuracy,lower power consumption,and longer range than radar,thus providing more safety to aircraft.The coverage of terrestrial radar and ADS-B is confined to continental parts of the globe,leaving oceans and poles uncovered by real-time surveillance measures.This study presents an optimized Low-Earth Orbit(LEO)-based ADS-B constellation for global air traffic surveillance over intercontinental trans-oceanic flight routes.The optimization algorithm is based on performance evaluation parameters,i.e.,coverage time,satellite availability,and orbit stability(precession and perigee rotation),and communication analysis.The results indicate that the constellation provides ample coverage in the simulated global oceanic regions.The constellation is a feasible and cost-effective solution for global air supervision,which can supplement terrestrial ADS-B and radar systems.
基金supported by the National Natural Science Foundation of China(61401489)
文摘At present, most of the passive radar system researches utilize FM radios, TV broadcasts, navigation satellites,etc. as illuminators. The transmitted signals are not specifically designed radar waveforms. In this work, the frequency agile, phased array air surveillance radar(ASR) is used as the illuminator of opportunity to detect the weak target. The phased array technology can help realize beam agility to track targets from different aspects simultaneously. The frequency agility technology is widely employed in radar system design to increase the ability of anti-jamming and increase the detection probability. While the frequency bandwidth of radar signals is usually wide and the range resolution is high, the range cell migration effect is obvious during the long time integration of non-cooperative bistatic radar. In this context, coherent integration methods are not applicable. In this work, a parametric non-coherent integration algorithm based on task de-interweaving is proposed. Numerical experiments verify that this is effective in weak target detection.
