西北太平洋副热带高压(简称西太副高)是影响东亚夏季天气气候的关键环流系统。本文利用CMIP5的历史气候模拟试验和RCP8.5路径下的未来气候变化预估试验数据,采用扰动位势高度,流函数等多种变量描述西太副高,分析了西太副高在6个全球变...西北太平洋副热带高压(简称西太副高)是影响东亚夏季天气气候的关键环流系统。本文利用CMIP5的历史气候模拟试验和RCP8.5路径下的未来气候变化预估试验数据,采用扰动位势高度,流函数等多种变量描述西太副高,分析了西太副高在6个全球变暖阈值(1.5℃, 2.0℃, 2.5℃,3.0℃, 3.5℃和4.0℃)下相对于当代气候的变化情况。在对流层中层(500 h Pa),西太副高在1.5℃阈值下几乎没有变化,而在2.0℃阈值下迅速减弱并东退约2.5°。当升温大于2.5℃时,西太副高呈线性减弱趋势,在4.0℃阈值下将东退约6.0°。在对流层低层(850 h Pa),西太副高在1.5℃阈值下增强西伸,但在升温到2.0℃的过程中变化不大。当变暖达到4.0℃阈值时,西太副高将西伸约2.0°。展开更多
Mid-high latitude Northern Asia is one of the most vulnerable and sensitive areas to global warming,but relatively less studied previously.We used an ensemble of a regional climate model(RegCM4)projections to assess f...Mid-high latitude Northern Asia is one of the most vulnerable and sensitive areas to global warming,but relatively less studied previously.We used an ensemble of a regional climate model(RegCM4)projections to assess future changes in surface air temperature,precipitation and Köppen-Trewartha(K-T)climate types in Northern Asia under the 1.5-4℃global warming targets.RegCM4 is driven by five CMIP5 global models over an East Asia domain at a grid spacing of 25 km.Validation of the present day(1986-2005)simulations shows that the ensembles of RegCM4(ensR)and driving GCMs(ensG)reproduce the major characters of the observed temperature,precipitation and K-T climate zones reasonably well.Greater and more realistic spatial detail is found in RegCM4 compared to the driving GCMs.A general warming and overall increases in precipitation are projected over the region,with these changes being more pronounced at higher warming levels.The projected warming by ensR shows different spatial patterns,and is in general lower,compared to ensG in most months of the year,while the percentage increases of precipitation are maximum during the cold months.The future changes in K-T climate zones are characterized by a substantial expansion of Dc(temperature oceanic)and retreat of Ec(sub-arctic continental)over the region,reaching∼20%under the 4℃warming level.The most notable change in climate types in ensR is found over Japan(∼60%),followed by Southern Siberia,Mongolia,and the Korean Peninsula(∼40%).The largest change in the K-T climate types is found when increasing from 2 to 3℃.The results will help to better assess the impacts of climate change and in implementation of appropriate adaptation measures over the region.展开更多
The acute effect of acupuncture on Alzheimer's disease,i.e.,on brain activation during treatment,has been reported.However,the effect of long-term acupuncture on brain activation in Alzheimer's disease is unclear.Th...The acute effect of acupuncture on Alzheimer's disease,i.e.,on brain activation during treatment,has been reported.However,the effect of long-term acupuncture on brain activation in Alzheimer's disease is unclear.Therefore,in this study,we performed long-term needling at Zusanli(ST36)or a sham point(1.5 mm lateral to ST36)in a rat Alzheimer's disease model,for 30 minutes,once per day,for 30 days.The rats underwent 18F-fluorodeoxyglucose positron emission tomography scanning.Positron emission tomography images were processed with SPM2.The brain areas activated after needling at ST36 included the left hippocampus,the left orbital cortex,the left infralimbic cortex,the left olfactory cortex,the left cerebellum and the left pons.In the sham-point group,the activated regions were similar to those in the ST36 group.However,the ST36 group showed greater activation in the cerebellum and pons than the sham-point group.These findings suggest that long-term acupuncture treatment has targeted regulatory effects on multiple brain regions in rats with Alzheimer's disease.展开更多
For target detection algorithm under global motion scene, this paper suggests a target detection algorithm based on motion attention fusion model. Firstly, the motion vector field is pre-processed by accumulation and ...For target detection algorithm under global motion scene, this paper suggests a target detection algorithm based on motion attention fusion model. Firstly, the motion vector field is pre-processed by accumulation and median filter;Then, according to the temporal and spatial character of motion vector, the attention fusion model is defined, which is used to detect moving target;Lastly, the edge of video moving target is made exactly by morphologic operation and edge tracking algorithm. The experimental results of different global motion video sequences show the proposed algorithm has a better veracity and speedup than other algorithm.展开更多
This article reports on and analyzes long-term projections of world food requirements compared with observed 2000 data reported by the United Nations’ Food and Agriculture Organization. The importance of this “post-...This article reports on and analyzes long-term projections of world food requirements compared with observed 2000 data reported by the United Nations’ Food and Agriculture Organization. The importance of this “post-mortem” is to strengthen the case for carrying out long-term projections of essential resources—food, energy, and non-fuel minerals— because of the long-lead times needed to insure that adequate global output levels of these basic ingredients of living standards will be met. This study should prove useful to those preparing today’s long-term projections, with world population projected to rise to over 9bn by mid-century.展开更多
The"Ninth Five-Year Plan for theNational Economy and SocialDevelopment and the Long-TermTarget by the Year 2010" adopted at theFourth Session of the Eighth National People’sCongress have opened up a vast ne...The"Ninth Five-Year Plan for theNational Economy and SocialDevelopment and the Long-TermTarget by the Year 2010" adopted at theFourth Session of the Eighth National People’sCongress have opened up a vast new worldfor the development of China’s food industry.The food industry should seize the opportunityto strengthen itself and speed up itsdevelopment for meeting the needs ofimproving the people’s living standards andperform well in modernized socialistconstruction.展开更多
Global Navigation Satellite System(GNSS)-based passive radar(GBPR)has been widely used in remote sensing applications.However,for moving target detection(MTD),the quadratic phase error(QPE)introduced by the non-cooper...Global Navigation Satellite System(GNSS)-based passive radar(GBPR)has been widely used in remote sensing applications.However,for moving target detection(MTD),the quadratic phase error(QPE)introduced by the non-cooperative target motion is usually difficult to be compensated,as the low power level of the GBPR echo signal renders the estimation of the Doppler rate less effective.Consequently,the moving target in GBPR image is usually defocused,which aggravates the difficulty of target detection even further.In this paper,a spawning particle filter(SPF)is proposed for defocused MTD.Firstly,the measurement model and the likelihood ratio function(LRF)of the defocused point-like target image are deduced.Then,a spawning particle set is generated for subsequent target detection,with reference to traditional particles in particle filter(PF)as their parent.After that,based on the PF estimator,the SPF algorithm and its sequential Monte Carlo(SMC)implementation are proposed with a novel amplitude estimation method to decrease the target state dimension.Finally,the effectiveness of the proposed SPF is demonstrated by numerical simulations and pre-liminary experimental results,showing that the target range and Doppler can be estimated accurately.展开更多
针对AGV(Automated Guided Vehicle)叉车处于环境信息未知或环境动态变化情况下的路径规划及导航问题,文中提出了一种由YOLOv5(You Only Look Once version 5)目标检测算法获取目标位置。根据目标位置规划出全局基础路径,再融合DWA(Dyna...针对AGV(Automated Guided Vehicle)叉车处于环境信息未知或环境动态变化情况下的路径规划及导航问题,文中提出了一种由YOLOv5(You Only Look Once version 5)目标检测算法获取目标位置。根据目标位置规划出全局基础路径,再融合DWA(Dynamic Window Approach)局部动态路径规划算法进行AGV路径规划与导航,使AGV叉车在未知环境或局部环境信息未知的环境中能快速识别目标位置并完成路径规划到达目标位置。实验结果表明,相较于改进前方法,文中所提方法在路径长度、耗费时间以及AGV叉车航向误差方面均有良好表现,路径长度平均减少12%,耗费时间平均减少约5%且AGV航向与目标航向的平均误差在5°以内。所提方法提高了AGV叉车在未知环境中的工作效率以及工作灵活性。展开更多
Airborne LIDAR can flexibly obtain point cloud data with three-dimensional structural information,which can improve its effectiveness of automatic target recognition in the complex environment.Compared with 2D informa...Airborne LIDAR can flexibly obtain point cloud data with three-dimensional structural information,which can improve its effectiveness of automatic target recognition in the complex environment.Compared with 2D information,3D information performs better in separating objects and background.However,an aircraft platform can have a negative influence on LIDAR obtained data because of various flight attitudes,flight heights and atmospheric disturbances.A structure of global feature based 3D automatic target recognition method for airborne LIDAR is proposed,which is composed of offline phase and online phase.The performance of four global feature descriptors is compared.Considering the summed volume region(SVR) discrepancy in real objects,SVR selection is added into the pre-processing operations to eliminate mismatching clusters compared with the interested target.Highly reliable simulated data are obtained under various sensor’s altitudes,detection distances and atmospheric disturbances.The final experiments results show that the added step increases the recognition rate by above 2.4% and decreases the execution time by about 33%.展开更多
基金This research was supported by the National Key R&D Program of China[grant number 2017YFA0603802]the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA2006040102]the National Natural Science Foundation of China[grant number 41675084].
基金This research was supported by the National Key R&D Program of China[grant number 2017YFA0603802]the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA2006040102]the National Natural Science Foundation of China[grant number 41675084].
文摘西北太平洋副热带高压(简称西太副高)是影响东亚夏季天气气候的关键环流系统。本文利用CMIP5的历史气候模拟试验和RCP8.5路径下的未来气候变化预估试验数据,采用扰动位势高度,流函数等多种变量描述西太副高,分析了西太副高在6个全球变暖阈值(1.5℃, 2.0℃, 2.5℃,3.0℃, 3.5℃和4.0℃)下相对于当代气候的变化情况。在对流层中层(500 h Pa),西太副高在1.5℃阈值下几乎没有变化,而在2.0℃阈值下迅速减弱并东退约2.5°。当升温大于2.5℃时,西太副高呈线性减弱趋势,在4.0℃阈值下将东退约6.0°。在对流层低层(850 h Pa),西太副高在1.5℃阈值下增强西伸,但在升温到2.0℃的过程中变化不大。当变暖达到4.0℃阈值时,西太副高将西伸约2.0°。
基金This research was jointly supported by the National Natural Science Foundation of China(41991284)the Science and Technology Project of Education Department of Jiangxi province(GJJ2201249).
文摘Mid-high latitude Northern Asia is one of the most vulnerable and sensitive areas to global warming,but relatively less studied previously.We used an ensemble of a regional climate model(RegCM4)projections to assess future changes in surface air temperature,precipitation and Köppen-Trewartha(K-T)climate types in Northern Asia under the 1.5-4℃global warming targets.RegCM4 is driven by five CMIP5 global models over an East Asia domain at a grid spacing of 25 km.Validation of the present day(1986-2005)simulations shows that the ensembles of RegCM4(ensR)and driving GCMs(ensG)reproduce the major characters of the observed temperature,precipitation and K-T climate zones reasonably well.Greater and more realistic spatial detail is found in RegCM4 compared to the driving GCMs.A general warming and overall increases in precipitation are projected over the region,with these changes being more pronounced at higher warming levels.The projected warming by ensR shows different spatial patterns,and is in general lower,compared to ensG in most months of the year,while the percentage increases of precipitation are maximum during the cold months.The future changes in K-T climate zones are characterized by a substantial expansion of Dc(temperature oceanic)and retreat of Ec(sub-arctic continental)over the region,reaching∼20%under the 4℃warming level.The most notable change in climate types in ensR is found over Japan(∼60%),followed by Southern Siberia,Mongolia,and the Korean Peninsula(∼40%).The largest change in the K-T climate types is found when increasing from 2 to 3℃.The results will help to better assess the impacts of climate change and in implementation of appropriate adaptation measures over the region.
基金supported by the National Basic Research Program of China(973 Program),No.2006CB504505,2012CB518504the National Natural Science Foundation of China,No.90709027+1 种基金the Student's Platform for Innovation and Entrepreneurship Training Program of Southern Medical University of China,No.201512121165the Doctoral Foundation of Guangdong Medical University of China,No.2XB13058
文摘The acute effect of acupuncture on Alzheimer's disease,i.e.,on brain activation during treatment,has been reported.However,the effect of long-term acupuncture on brain activation in Alzheimer's disease is unclear.Therefore,in this study,we performed long-term needling at Zusanli(ST36)or a sham point(1.5 mm lateral to ST36)in a rat Alzheimer's disease model,for 30 minutes,once per day,for 30 days.The rats underwent 18F-fluorodeoxyglucose positron emission tomography scanning.Positron emission tomography images were processed with SPM2.The brain areas activated after needling at ST36 included the left hippocampus,the left orbital cortex,the left infralimbic cortex,the left olfactory cortex,the left cerebellum and the left pons.In the sham-point group,the activated regions were similar to those in the ST36 group.However,the ST36 group showed greater activation in the cerebellum and pons than the sham-point group.These findings suggest that long-term acupuncture treatment has targeted regulatory effects on multiple brain regions in rats with Alzheimer's disease.
基金Acknowledgments This research was jointly supported by the National Key Research and Development Program of China (2016YFA0600701), the National Natural Science Foundation of China (41675069), and the Climate Change Specific Fund of China (CCSF201731).
基金This research was supported by the National Key R&D Program of China (2017YFA0603802), the National Natural Science Foundation of China (41661144005 and 41320104007), and the CAS-PKU Joint Research Program. We would like to thanks the IPCC for providing the CMIP5 datasets (http://www.ipccdata.org/sim/gcm_monthly/AR5/Reference-Archive.html).
文摘For target detection algorithm under global motion scene, this paper suggests a target detection algorithm based on motion attention fusion model. Firstly, the motion vector field is pre-processed by accumulation and median filter;Then, according to the temporal and spatial character of motion vector, the attention fusion model is defined, which is used to detect moving target;Lastly, the edge of video moving target is made exactly by morphologic operation and edge tracking algorithm. The experimental results of different global motion video sequences show the proposed algorithm has a better veracity and speedup than other algorithm.
文摘This article reports on and analyzes long-term projections of world food requirements compared with observed 2000 data reported by the United Nations’ Food and Agriculture Organization. The importance of this “post-mortem” is to strengthen the case for carrying out long-term projections of essential resources—food, energy, and non-fuel minerals— because of the long-lead times needed to insure that adequate global output levels of these basic ingredients of living standards will be met. This study should prove useful to those preparing today’s long-term projections, with world population projected to rise to over 9bn by mid-century.
文摘The"Ninth Five-Year Plan for theNational Economy and SocialDevelopment and the Long-TermTarget by the Year 2010" adopted at theFourth Session of the Eighth National People’sCongress have opened up a vast new worldfor the development of China’s food industry.The food industry should seize the opportunityto strengthen itself and speed up itsdevelopment for meeting the needs ofimproving the people’s living standards andperform well in modernized socialistconstruction.
基金supported by the National Natural Science Foundation of China(62101014)the National Key Laboratory of Science and Technology on Space Microwave(6142411203307).
文摘Global Navigation Satellite System(GNSS)-based passive radar(GBPR)has been widely used in remote sensing applications.However,for moving target detection(MTD),the quadratic phase error(QPE)introduced by the non-cooperative target motion is usually difficult to be compensated,as the low power level of the GBPR echo signal renders the estimation of the Doppler rate less effective.Consequently,the moving target in GBPR image is usually defocused,which aggravates the difficulty of target detection even further.In this paper,a spawning particle filter(SPF)is proposed for defocused MTD.Firstly,the measurement model and the likelihood ratio function(LRF)of the defocused point-like target image are deduced.Then,a spawning particle set is generated for subsequent target detection,with reference to traditional particles in particle filter(PF)as their parent.After that,based on the PF estimator,the SPF algorithm and its sequential Monte Carlo(SMC)implementation are proposed with a novel amplitude estimation method to decrease the target state dimension.Finally,the effectiveness of the proposed SPF is demonstrated by numerical simulations and pre-liminary experimental results,showing that the target range and Doppler can be estimated accurately.
文摘针对AGV(Automated Guided Vehicle)叉车处于环境信息未知或环境动态变化情况下的路径规划及导航问题,文中提出了一种由YOLOv5(You Only Look Once version 5)目标检测算法获取目标位置。根据目标位置规划出全局基础路径,再融合DWA(Dynamic Window Approach)局部动态路径规划算法进行AGV路径规划与导航,使AGV叉车在未知环境或局部环境信息未知的环境中能快速识别目标位置并完成路径规划到达目标位置。实验结果表明,相较于改进前方法,文中所提方法在路径长度、耗费时间以及AGV叉车航向误差方面均有良好表现,路径长度平均减少12%,耗费时间平均减少约5%且AGV航向与目标航向的平均误差在5°以内。所提方法提高了AGV叉车在未知环境中的工作效率以及工作灵活性。
基金This research was supported by National Natural Science Foundation of China(No.61271353,61871389)Major Funding Projects of National University of Defense Technology(No.ZK18-01-02)Foundation of State Key Laboratory of Pulsed Power Laser Technology(No.SKL2018ZR09).
文摘Airborne LIDAR can flexibly obtain point cloud data with three-dimensional structural information,which can improve its effectiveness of automatic target recognition in the complex environment.Compared with 2D information,3D information performs better in separating objects and background.However,an aircraft platform can have a negative influence on LIDAR obtained data because of various flight attitudes,flight heights and atmospheric disturbances.A structure of global feature based 3D automatic target recognition method for airborne LIDAR is proposed,which is composed of offline phase and online phase.The performance of four global feature descriptors is compared.Considering the summed volume region(SVR) discrepancy in real objects,SVR selection is added into the pre-processing operations to eliminate mismatching clusters compared with the interested target.Highly reliable simulated data are obtained under various sensor’s altitudes,detection distances and atmospheric disturbances.The final experiments results show that the added step increases the recognition rate by above 2.4% and decreases the execution time by about 33%.