随着人们对人数统计需求的不断增长,基于信道状态信息(channel state information,CSI)的人流量监测技术因其易于部署、保护隐私和适用性强等优势而备受关注.然而,在现有的人流量监测工作中,人数识别的准确率容易受到人群密集程度的影响...随着人们对人数统计需求的不断增长,基于信道状态信息(channel state information,CSI)的人流量监测技术因其易于部署、保护隐私和适用性强等优势而备受关注.然而,在现有的人流量监测工作中,人数识别的准确率容易受到人群密集程度的影响.为了保证监测精度,通常只能在人群稀疏的情况下进行监测,这导致了基于CSI的人流量监测技术缺乏实用性.为了解决这一问题,提出了一种能够识别连续性人流的监测方法.该方法首先利用解卷绕和线性相位校正算法,对原始数据进行相位补偿并消除随机相位偏移;然后通过标准差和方差提取连续性人流数据中的有效数据包;最后将时域上的相位差信息作为特征信号输入到深度学习的CLDNN(convolutional,long short-term memory,deep neural network)中进行人数识别.经过实验测试,该方法在前后排行人距离不小于1 m的情况下,分别实现了室外96.7%和室内94.1%的准确率,优于现有的人流量监测方法.展开更多
To investigate chemical profiles and formation mechanisms of aerosol particles in winter haze events,comprehensive measurements including hourly concentrations of PM2.5 and water-soluble inorganic ions and related gas...To investigate chemical profiles and formation mechanisms of aerosol particles in winter haze events,comprehensive measurements including hourly concentrations of PM2.5 and water-soluble inorganic ions and related gasphase precursors were conducted via an online monitoring system from January to March of 2016 in Shenzhen,a coastal mega-city in south China.In this study,high concentrations of PM2.5,NO2 and lower levels of O3 were observed during haze periods in comparison with clear days(Visibility>15 km).The major secondary ionic species were NH+4、NO-3 and SO2-4,which varied significantly on haze and clear days.The ratio of NO-3/SO2-4 in haze days was greater than that on clear days and tended to be larger when air pollution became more serious.At the same time,compared with previous studies,it has been found that the ratio has been increasing gradually in Shenzhen,indicating that the motor vehicle exhaust emissions have a more and more important impact on air quality in Shenzhen.Sulfur oxidation rate(SOR)and nitrogen oxidation rate(NOR)was higher during the haze period than that in clean days,indicating efficient gas to particle conversion.Further analysis shows that high concentrations of sulfate might be explained by aqueous oxidation,but gas-phase reactions might dominate nitrate formation.This study also highlights that wintertime nitrate formation can be an important contributor to aerosol particles,especially during haze periods.展开更多
The sea potato Acaudina spp.is a species of sea cucumber,belonging to the class Holothuroidea under Phylum Echino-dermata.It becomes blooming recently in the East Sea of China,causing serious ecological problems.Howev...The sea potato Acaudina spp.is a species of sea cucumber,belonging to the class Holothuroidea under Phylum Echino-dermata.It becomes blooming recently in the East Sea of China,causing serious ecological problems.However,until now there are no molecular data for its larval identification and population genetic analysis.In this study,we firstly screened a mtDNA fragment and demonstrated that it was the species-specific molecular marker for the identification of Acaudina spp.We then developed a quantitative polymerase chain reaction(PCR)method to evaluate the larval density of Acaudina spp.based on this molecular probe.Utilizing this method,we examined 116 plankton samples collected in four seasons from 13 stations along the coastal region in Fu-jian province,China.The results showed that the high larval density was presented at stations 1,2,and 3,which were near a quay in the coast.The larval density increased from April and reached the highest value in June and July,suggesting temperature might be the main environmental factor on the effects of its population distribution and density.Our work provides an important molecular tool for species identification and risk evaluation of a potentially invasive species.展开更多
基金National Key Research and Development Program(2016YFC0203603)Guangdong Basic and Applied Basic Research Foundation(2019A1515012008)Youth Fund of National Natural Science s(41605002)
文摘To investigate chemical profiles and formation mechanisms of aerosol particles in winter haze events,comprehensive measurements including hourly concentrations of PM2.5 and water-soluble inorganic ions and related gasphase precursors were conducted via an online monitoring system from January to March of 2016 in Shenzhen,a coastal mega-city in south China.In this study,high concentrations of PM2.5,NO2 and lower levels of O3 were observed during haze periods in comparison with clear days(Visibility>15 km).The major secondary ionic species were NH+4、NO-3 and SO2-4,which varied significantly on haze and clear days.The ratio of NO-3/SO2-4 in haze days was greater than that on clear days and tended to be larger when air pollution became more serious.At the same time,compared with previous studies,it has been found that the ratio has been increasing gradually in Shenzhen,indicating that the motor vehicle exhaust emissions have a more and more important impact on air quality in Shenzhen.Sulfur oxidation rate(SOR)and nitrogen oxidation rate(NOR)was higher during the haze period than that in clean days,indicating efficient gas to particle conversion.Further analysis shows that high concentrations of sulfate might be explained by aqueous oxidation,but gas-phase reactions might dominate nitrate formation.This study also highlights that wintertime nitrate formation can be an important contributor to aerosol particles,especially during haze periods.
基金This work was supported by the National Key Research and Development Program of China(No.2018YFD0900705)the Key Laboratory of Integrated Marine Monitor-ing and Applied Technologies for Harmful Algal Blooms Funds(No.MATHAB201706)the Fundamental Re-search Funds for the Central Universities(No.201822016).
文摘The sea potato Acaudina spp.is a species of sea cucumber,belonging to the class Holothuroidea under Phylum Echino-dermata.It becomes blooming recently in the East Sea of China,causing serious ecological problems.However,until now there are no molecular data for its larval identification and population genetic analysis.In this study,we firstly screened a mtDNA fragment and demonstrated that it was the species-specific molecular marker for the identification of Acaudina spp.We then developed a quantitative polymerase chain reaction(PCR)method to evaluate the larval density of Acaudina spp.based on this molecular probe.Utilizing this method,we examined 116 plankton samples collected in four seasons from 13 stations along the coastal region in Fu-jian province,China.The results showed that the high larval density was presented at stations 1,2,and 3,which were near a quay in the coast.The larval density increased from April and reached the highest value in June and July,suggesting temperature might be the main environmental factor on the effects of its population distribution and density.Our work provides an important molecular tool for species identification and risk evaluation of a potentially invasive species.
