Lanzhou Zhongchuan International Airport[International Civil Aviation Organization(ICAO)code ZLLL]is located in a wind shear prone area in China,where most low-level wind shear events occur in dry weather conditions.W...Lanzhou Zhongchuan International Airport[International Civil Aviation Organization(ICAO)code ZLLL]is located in a wind shear prone area in China,where most low-level wind shear events occur in dry weather conditions.We analyzed temporal distribution and synoptic circulation background for 18 dry wind shear events reported by pilots at ZLLL by using the NCEP final(FNL)operational global analysis data,and then proposed a lidar-based regional divergence algorithm(RDA)to determine wind shear intensity and location.Low-level wind shear at ZLLL usually occurs in the afternoon and evening in dry conditions.Most wind shear events occur in an unstable atmosphere over ZLLL,with changes in wind speed or direction generally found at 700 hPa and 10-m height.Based on synoptic circulations at 700 hPa,wind shear events could be classified as strong northerly,convergence,southerly,and weak wind types.The proposed RDA successfully identified low-level wind shear except one southerly case,achieving94%alerting rate compared with 82%for the operational system at ZLLL and 88%for the ramp detection algorithm(widely used in some operational alert systems)based on the same dataset.The RDA-unidentified southerly case occurred in a near neutral atmosphere,and wind speed change could not be captured by the Doppler lidar.展开更多
A large part of our daily lives is spent with audio information. Massive obstacles are frequently presented by the colossal amounts of acoustic information and the incredibly quick processing times. This results in th...A large part of our daily lives is spent with audio information. Massive obstacles are frequently presented by the colossal amounts of acoustic information and the incredibly quick processing times. This results in the need for applications and methodologies that are capable of automatically analyzing these contents. These technologies can be applied in automatic contentanalysis and emergency response systems. Breaks in manual communication usually occur in emergencies leading to accidents and equipment damage. The audio signal does a good job by sending a signal underground, which warrants action from an emergency management team at the surface. This paper, therefore, seeks to design and simulate an audio signal alerting and automatic control system using Unity Pro XL to substitute manual communication of emergencies and manual control of equipment. Sound data were trained using the neural network technique of machine learning. The metrics used are Fast Fourier transform magnitude, zero crossing rate, root mean square, and percentage error. Sounds were detected with an error of approximately 17%;thus, the system can detect sounds with an accuracy of 83%. With more data training, the system can detect sounds with minimal or no error. The paper, therefore, has critical policy implications about communication, safety, and health for underground mine.展开更多
Background Selective attention is considered one of the main components of cognitive functioning.A number of studies have demonstrated gender differences in cognition.This study aimed to investigate the gender differe...Background Selective attention is considered one of the main components of cognitive functioning.A number of studies have demonstrated gender differences in cognition.This study aimed to investigate the gender differences in selective attention in healthy subjects.Methods The present experiment examined the gender differences associated with the efficiency of three attentional networks：alerting,orienting,and executive control attention in 73 healthy subjects （38 males）.All participants performed a modified version of the Attention Network Test （ANT）.Results Females had higher orienting scores than males （t=2.172,P 〈0.05）.Specifically,females were faster at covert orienting of attention to a spatially cued location.There were no gender differences between males and females in alerting （t=0.813,P 〉0.05） and executive control （t=0.945,P 〉0.05） attention networks.Conclusions There was a significant gender difference between males and females associated with the orienting network.Enhanced orienting attention in females may function to motivate females to direct their attention to a spatially cued location.展开更多
根据Supervisory Control and Data Acquisition(SCADA)系统异常监测值能及时预警供水管网爆管,但由于用水周期变化、随机波动及监测误差,导致实际中很难预警较小爆管.针对该难题,开展了基于自适应卡尔曼滤波的供水管网爆管信号识别研究...根据Supervisory Control and Data Acquisition(SCADA)系统异常监测值能及时预警供水管网爆管,但由于用水周期变化、随机波动及监测误差,导致实际中很难预警较小爆管.针对该难题,开展了基于自适应卡尔曼滤波的供水管网爆管信号识别研究,提出将历史监测数据按用水周期分解,采用自适应卡尔曼滤波结合平均低通滤波对管网供水量进行实时估计,根据监测值与估计值的差,预警爆管、估算爆管流量.分别采用仿真数据与实测数据验证所提出方法,结果表明,所提出方法可用于实际供水管网爆管预警;对所采用实测数据,爆管预警精度约为最大时水量的9%;此外,实际爆管预警精度主要取决于用水量本身的随机波动,同时与监测数据采样频率相关.展开更多
The World Meteorological Organization(WMO) is planning to implement a Global Multi-hazard Alert System(GMAS) to aggregate official warning^1 information issued by authorities around the world and to serve as a one-sto...The World Meteorological Organization(WMO) is planning to implement a Global Multi-hazard Alert System(GMAS) to aggregate official warning^1 information issued by authorities around the world and to serve as a one-stop shop to support the humanitarian organizations of the United Nations(UN), National Meteorological and Hydrological Services(NMHSs) and other global users including the media. It aims to enhance the authority and visibility of NMHSs and other alerting authorities. To aid effective dissemination of warnings to GMAS, the Common Alerting Protocol(CAP) was considered as a standard and robust format to use. In respect of GMAS infrastructure, the World Weather Information(WWIS) and the Severe Weather Information Centre(SWIC) of WMO as well as the WMO Alert Hub now being implemented are identified as core components, among others. The SWIC is being upgraded with GIS capability for displaying authoritative warnings and tropical cyclone(TC) information, and for use as a display platform of GMAS. Apart from warnings from NMHSs, authoritative TC warnings and advisories issued by Regional Specialized Meteorological Centres(RSMCs) and Tropical Cyclone Warning Centres(TCWCs) are also indispensable information for GMAS. As the existing TC warnings and advisories, now more or less in free text format, are mainly targeted for human users and are not intended for automatic parsing by computer software, it is proposed to make available the TC advisories in a machine-readable format so that TC information can be effectively ingested into GMAS and made available to the UN humanitarian organizations, NMHSs and other global users. In this respect, some enhancement measures to TC advisories are proposed. This calls for active collaboration of Members of the Typhoon Committee in the GMAS project.展开更多
基金Supported by the National Natural Science Foundation of China(41275102)Science and Technology Project of the Northwest Air Traffic Management Bureau of Civil Aviation of China in 2017Special Fund for National Science and Technology Basic Research Program of China(2017FY100900).
文摘Lanzhou Zhongchuan International Airport[International Civil Aviation Organization(ICAO)code ZLLL]is located in a wind shear prone area in China,where most low-level wind shear events occur in dry weather conditions.We analyzed temporal distribution and synoptic circulation background for 18 dry wind shear events reported by pilots at ZLLL by using the NCEP final(FNL)operational global analysis data,and then proposed a lidar-based regional divergence algorithm(RDA)to determine wind shear intensity and location.Low-level wind shear at ZLLL usually occurs in the afternoon and evening in dry conditions.Most wind shear events occur in an unstable atmosphere over ZLLL,with changes in wind speed or direction generally found at 700 hPa and 10-m height.Based on synoptic circulations at 700 hPa,wind shear events could be classified as strong northerly,convergence,southerly,and weak wind types.The proposed RDA successfully identified low-level wind shear except one southerly case,achieving94%alerting rate compared with 82%for the operational system at ZLLL and 88%for the ramp detection algorithm(widely used in some operational alert systems)based on the same dataset.The RDA-unidentified southerly case occurred in a near neutral atmosphere,and wind speed change could not be captured by the Doppler lidar.
文摘A large part of our daily lives is spent with audio information. Massive obstacles are frequently presented by the colossal amounts of acoustic information and the incredibly quick processing times. This results in the need for applications and methodologies that are capable of automatically analyzing these contents. These technologies can be applied in automatic contentanalysis and emergency response systems. Breaks in manual communication usually occur in emergencies leading to accidents and equipment damage. The audio signal does a good job by sending a signal underground, which warrants action from an emergency management team at the surface. This paper, therefore, seeks to design and simulate an audio signal alerting and automatic control system using Unity Pro XL to substitute manual communication of emergencies and manual control of equipment. Sound data were trained using the neural network technique of machine learning. The metrics used are Fast Fourier transform magnitude, zero crossing rate, root mean square, and percentage error. Sounds were detected with an error of approximately 17%;thus, the system can detect sounds with an accuracy of 83%. With more data training, the system can detect sounds with minimal or no error. The paper, therefore, has critical policy implications about communication, safety, and health for underground mine.
基金This work was supported by grants from the National Natural Science Foundation of China （No. 30870766）, the National Basic Research Program of China （973 Program） （No. 2011CB707805）, and International Program of Anhui Province （No. 10080703040）. Conflict of interest： None.
文摘Background Selective attention is considered one of the main components of cognitive functioning.A number of studies have demonstrated gender differences in cognition.This study aimed to investigate the gender differences in selective attention in healthy subjects.Methods The present experiment examined the gender differences associated with the efficiency of three attentional networks：alerting,orienting,and executive control attention in 73 healthy subjects （38 males）.All participants performed a modified version of the Attention Network Test （ANT）.Results Females had higher orienting scores than males （t=2.172,P 〈0.05）.Specifically,females were faster at covert orienting of attention to a spatially cued location.There were no gender differences between males and females in alerting （t=0.813,P 〉0.05） and executive control （t=0.945,P 〉0.05） attention networks.Conclusions There was a significant gender difference between males and females associated with the orienting network.Enhanced orienting attention in females may function to motivate females to direct their attention to a spatially cued location.
文摘根据Supervisory Control and Data Acquisition(SCADA)系统异常监测值能及时预警供水管网爆管,但由于用水周期变化、随机波动及监测误差,导致实际中很难预警较小爆管.针对该难题,开展了基于自适应卡尔曼滤波的供水管网爆管信号识别研究,提出将历史监测数据按用水周期分解,采用自适应卡尔曼滤波结合平均低通滤波对管网供水量进行实时估计,根据监测值与估计值的差,预警爆管、估算爆管流量.分别采用仿真数据与实测数据验证所提出方法,结果表明,所提出方法可用于实际供水管网爆管预警;对所采用实测数据,爆管预警精度约为最大时水量的9%;此外,实际爆管预警精度主要取决于用水量本身的随机波动,同时与监测数据采样频率相关.
文摘The World Meteorological Organization(WMO) is planning to implement a Global Multi-hazard Alert System(GMAS) to aggregate official warning^1 information issued by authorities around the world and to serve as a one-stop shop to support the humanitarian organizations of the United Nations(UN), National Meteorological and Hydrological Services(NMHSs) and other global users including the media. It aims to enhance the authority and visibility of NMHSs and other alerting authorities. To aid effective dissemination of warnings to GMAS, the Common Alerting Protocol(CAP) was considered as a standard and robust format to use. In respect of GMAS infrastructure, the World Weather Information(WWIS) and the Severe Weather Information Centre(SWIC) of WMO as well as the WMO Alert Hub now being implemented are identified as core components, among others. The SWIC is being upgraded with GIS capability for displaying authoritative warnings and tropical cyclone(TC) information, and for use as a display platform of GMAS. Apart from warnings from NMHSs, authoritative TC warnings and advisories issued by Regional Specialized Meteorological Centres(RSMCs) and Tropical Cyclone Warning Centres(TCWCs) are also indispensable information for GMAS. As the existing TC warnings and advisories, now more or less in free text format, are mainly targeted for human users and are not intended for automatic parsing by computer software, it is proposed to make available the TC advisories in a machine-readable format so that TC information can be effectively ingested into GMAS and made available to the UN humanitarian organizations, NMHSs and other global users. In this respect, some enhancement measures to TC advisories are proposed. This calls for active collaboration of Members of the Typhoon Committee in the GMAS project.
