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Different Impacts of Madden–Julian Oscillation on Winter Rainfall over Southern China

Journal of Meteorological Research 2021年第2期35卷 271-281页

作者： Xiong CHEN Jian LING Chongyin LI Lifeng LI minghao yang College of Meteorology and Oceanography National University of Defense TechnologyNanjing 211101 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100049

Winter rainfall over southern China is usually enhanced when Madden–Julian oscillation(MJO) is active over the Indian Ocean, but it can be weakened under certain conditions. Here, the diversity of MJO impacts on winter rainfall and its mechanisms are explored by using scenarios of enhanced and suppressed rainfall anomalies over southern China when MJO is active over the Indian Ocean. The combined effects of low-frequency background moisture and intraseasonal winds are the major contributors to the different rainfall anomalies. Anomalous circulation in mid–high latitudes, especially on intraseasonal timescales, is almost opposite in the two scenarios, which can modulate the response of extratropical atmosphere to MJO heating and then induces the different circulations over southern China. In the enhanced scenario, mid–high latitudes of Eurasia and southern China are dominated by positive and negative sea level pressure anomalies, respectively. The southerly over southern China and the South China Sea induced by MJO heating promotes the anomalous moisture convergence and ascending motion over southern China, resulting in the enhanced rainfall. In the suppressed scenario, however, the circulation in mid–high latitudes does not favor rainfall over southern China and leads to the northerly response to MJO heating over southern China, which enhances moisture divergence and weakens rainfall over southern China.

关键词： Madden–Julian oscillation(MJO) winter rainfall southern China moisture diagnoses

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The Linkage between Midwinter Suppression of the North Pacific Storm Track and Atmospheric Circulation Features in the Northern Hemisphere

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Advances in Atmospheric Sciences 2022年第3期39卷 502-518页

作者： minghao yang Chongyin LI Xin LI Xiong CHEN Lifeng LI College of Meteorology and Oceanography National University of Defense TechnologyChangsha 410073China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

The midwinter suppression(MWS) of the North Pacific storm track(NPST) has been an active research topic for decades. Based on the daily-mean NCEP/NCAR reanalysis from 1948 to 2018, this study investigates the MWS-related atmospheric circulation characteristics in the Northern Hemisphere by regression analysis with respect to a new MWS index, which may shed more light on this difficult issue. The occurrence frequency of the MWS of the upper-tropospheric NPST is more than 0.8 after the mid-1980 s. The MWS is accompanied by significantly positive sea-level pressure anomalies in Eurasia and negative anomalies over the North Pacific, which correspond to a strengthened East Asian winter monsoon. The intensified East Asian trough and atmospheric blocking in the North Pacific as well as the significantly negative low-level air temperature anomalies, lying upstream of the MNPST, are expected to be distinctly associated with the MWS. However, the relationship between the MWS and low-level atmospheric baroclinicity is somewhat *** the diagnostics of the eddy energy budget, it is identified that the inefficiency of the barotropic energy conversion related to the barotropic governor mechanism does not favor the occurrence of the MWS. In contrast, weakened baroclinic energy conversion, buoyancy conversion, and generation of eddy available potential energy by diabatic heating are conducive to the occurrence of the MWS. In addition, Ural blocking in the upstream region of the MNPST may be another candidate mechanism associated with the MWS.

关键词： midwinter suppression North Pacific storm track anomalous atmospheric circulation eddy energy budget

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Response of the North Pacific Storm Track Activity in the Cold Season to Multi-scale Oceanic Variations of Kuroshio Extension System: A Statistical Assessment

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Advances in Atmospheric Sciences 2023年第3期40卷 514-530页

作者： Peilong YU minghao yang Chao ZHANG Yi LI Lifeng ZHANG Shiyao CHEN Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment ChangeNanjing University of Information Science and TechnologyNanjing 210044China College of Meteorology and Oceanography National University of Defense TechnologyChangsha 410073China

In this paper,a statistical method called Generalized Equilibrium Feedback Analysis(GEFA)is used to investigate the responses of the North Pacific Storm Track(NPST)in the cold season to the multi-scale oceanic variations of the Kuroshio Extension(KE)system,including its large-scale variation,oceanic front meridional shift,and mesoscale eddy *** show that in the cold season from the lower to the upper troposphere,the KE large-scale variation significantly weakens the storm track activity over the central North Pacific south of 30°*** northward shift of the KE front significantly strengthens the storm track activity over the western and central North Pacific south of 40°N,resulting in a southward shift of the *** contrast,the NPST response to KE mesoscale eddy activity is not so significant and relatively shallow,which only shows some significant positive signals near the dateline in the lower and middle ***,it is found that baroclinicity and baroclinic energy conversion play an important role in the formation of the NPST response to the KE multi-scale oceanic variations.

关键词： generalized equilibrium feedback analysis Kuroshio Extension multi-scale oceanic variations North Pacific storm track

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Review of micro-expression spotting and recognition in video sequences

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Virtual Reality & Intelligent Hardware 2021年第1期3卷 1-17页

作者： Hang PAN Lun XIE Zhiliang WANG Bin LIU minghao yang Jianhua TAO School of Computer and Communication Engineering University of Science and Technology BeijingBeijing 100083China National Laboratory of Pattern Recognition Institute of AutomationChinese Academy of SciencesBeijing 100190China

Facial micro-expressions are short and imperceptible expressions that involuntarily reveal the true emotions that a person may be attempting to suppress,hide,disguise,or *** expressions can reflect a person's real emotions and have a wide range of application in public safety and clinical *** analysis of facial micro-expressions in video sequences through computer vision is still relatively *** this research,a comprehensive review on the topic of spotting and recognition used in micro expression analysis databases and methods,is conducted,and advanced technologies in this area are *** addition,we discuss challenges that remain unresolved alongside future work to be completed in the field of micro-expression analysis.

关键词： Facial expression Micro-expression spotting Micro-expression recognition Database Review

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PEGA:probabilistic environmental gradient-driven genetic algorithm considering epigenetic traits to balance global and local optimizations

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Frontiers of Information Technology & Electronic Engineering 2024年第6期25卷 839-855页

作者： Zhiyu DUAN Shunkun yang Qi SHAO minghao yang School of Reliability and Systems Engineering Beihang UniversityBeijing 100191China

Epigenetics’flexibility in terms of finer manipulation of genes renders unprecedented levels of refined and diverse evolutionary mechanisms *** the epigenetic perspective,the main limitations to improving the stability and accuracy of genetic algorithms are as follows:(1)the unchangeable nature of the external environment,which leads to excessive disorders in the changed phenotype after mutation and crossover;(2)the premature convergence due to the limited types of epigenetic *** this paper,a probabilistic environmental gradientdriven genetic algorithm(PEGA)considering epigenetic traits is *** enhance the local convergence efficiency and acquire stable local search,a probabilistic environmental gradient(PEG)descent strategy together with a multi-dimensional heterogeneous exponential environmental vector tendentiously generates more offsprings along the gradient in the solution ***,to balance exploration and exploitation at different evolutionary stages,a variable nucleosome reorganization(VNR)operator is realized by dynamically adjusting the number of genes involved in mutation and *** on the above-mentioned operators,three epigenetic operators are further introduced to weaken the possible premature problem by enriching genetic *** experimental results on the open Congress on Evolutionary Computation-2017(CEC’17)benchmark over 10-,30-,50-,and 100-dimensional tests indicate that the proposed method outperforms 10 state-of-the-art evolutionary and swarm algorithms in terms of accuracy and stability on comprehensive *** ablation analysis demonstrates that for accuracy and stability,the fusion strategy of PEG and VNR are effective on 96.55%of the test functions and can improve the indicators by up to four orders of ***,the performance of PEGA on the real-world spacecraft trajectory optimization problem is the best in terms of quality of the solution.

关键词： Evolutionary algorithm Epigenetics Epigenetic algorithm Probabilistic environmental vector Variable nucleosome reorganization

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Individual aortic baroreceptors are sensitive to different ranges of blood pressures

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Science China(Life Sciences) 2014年第7期57卷 502-509页

作者： CHEN MengJiao yang minghao HAN WenJuan AN ShuCheng LIU YiHui LIU ZhiQiang REN Wei MOE Key Laboratory for Modern Teaching Technology and College of Life Sciences Shaanxi Normal University

Many receptors,including thermal receptors and mechanical receptors,are only activated by stimuli within a clearly defined range of *** in the receptive ranges enable individual receptors and their sensory centers to precisely detect the intensity of the stimulus and changes in *** are the sensory terminals of the *** is well understood that an increasing number of baroreceptors are recruited to produce afferent action potentials as the blood pressure increases,indicating that individual baroreceptors have different pressure *** present study revealed that individual baroreceptors could stop their afferent signals when the blood pressure exceeds a certain level,indicating that individual baroreceptors are sensitive to a specific range of blood *** receptive ranges of individual baroreceptors differ in terms of the total range,the lower threshold,and the upper *** 85 baroreceptors examined in this study,the upper thresholds for about half were within the physiological blood pressure *** results indicate that supraphysiological blood pressure is unlikely to be encoded by the recruitment of more ***,supraphysiological blood pressure levels might be signaled by an increase in the frequency of action potentials or by other *** conclusion,our results indicate that rabbit baroreceptors are activated by blood pressure levels within specific receptive *** findings should encourage further studies to examine the role of population coding of blood pressure by baroreceptors in the baroreflex.

关键词： depolarization block receptive range rabbit depressor nerve single fiber recording

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基于模糊聚类的电力系统载荷能力安全预警方法

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电力系统自动化 2007年第22期31卷 31-35页

作者：张菁杨明皓中国农业大学信息与电气学院北京市100083

针对电力系统静态安全分析工程应用的需要,提出了以节点载荷能力为核心的电压稳定指标预警分析方法。该方法用红、黄、绿3种通用的预警颜色分段标识系统能够承受单一节点负荷增长的能力,并给出各预警色段所允许的节点载荷能力的界域。... 详细信息

针对电力系统静态安全分析工程应用的需要,提出了以节点载荷能力为核心的电压稳定指标预警分析方法。该方法用红、黄、绿3种通用的预警颜色分段标识系统能够承受单一节点负荷增长的能力,并给出各预警色段所允许的节点载荷能力的界域。将能够表征节点载荷能力的相关电压稳定指标定义为聚类特征向量,基于各节点的实时特征向量值对系统中所有带负荷的节点进行模糊聚类,然后按照着色逻辑规则对聚类中心特征向量值和相应的聚类节点集进行着色分析。各预警色段节点集所允许的负荷增长范围可以通过离线仿真获得。IEEE30系统的仿真试验验证了该方法的有效性和实用性。

关键词：静态安全分析电压稳定指标预警模糊聚类电力系统

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农村户用风/光/水互补发电与供电系统的可行性

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农业工程学报 2008年第8期24卷 178-181页

作者：井天军杨明皓中国农业大学信息与电气工程学院北京100083

在分析中国农村用能和供能现状的基础上,从农村经济可持续发展和国家中长期发展战略的角度论证了农村户用风/水/光互补发电技术研究的必要性。提出研究与开发农村户用风水光发电与供电系统,并通过分析国内外现有技术基础论证了其可行性... 详细信息

在分析中国农村用能和供能现状的基础上,从农村经济可持续发展和国家中长期发展战略的角度论证了农村户用风/水/光互补发电技术研究的必要性。提出研究与开发农村户用风水光发电与供电系统,并通过分析国内外现有技术基础论证了其可行性和技术关键,最后分析和预测了该技术的产业前景。

关键词：户用发电互补发电系统农村电力微型电网

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电力市场中分布式发电孤岛模式对配电公司费用的影响

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电力系统自动化 2009年第2期33卷 15-19页

作者：魏玲杨明皓中国农业大学信息与电气工程学院北京市100083

在分布式发电参与的电力市场中,提出了一种考虑可中断负荷及其费用的配电公司最小总费用模型。在对传统运行模式、孤岛运行模式,以及非故障馈线支援模式进行比较的基础上,重点分析了不同负荷水平下分布式发电孤岛运行模式对配电系统的... 详细信息

在分布式发电参与的电力市场中,提出了一种考虑可中断负荷及其费用的配电公司最小总费用模型。在对传统运行模式、孤岛运行模式,以及非故障馈线支援模式进行比较的基础上,重点分析了不同负荷水平下分布式发电孤岛运行模式对配电系统的有功网损、配电网络的节点边际电价和配电公司购电费用的影响。数值计算和算例仿真表明,当配电网出现故障时,利用分布式发电形成的安全孤岛可以减少整个系统的失电负荷量、降低配电公司的购电总费用。同时,可以根据非故障馈线的容量裕度,实施最佳的支援方式。

关键词：分布式发电孤岛模式总费用配电公司容量裕度电力市场

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基于周期性无功电流扰动的孤岛检测新方法

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电工技术学报 2014年第3期29卷 270-276页

作者：钟诚井天军杨明皓中国农业大学信息与电气工程学院北京100083 东北电力大学电气工程学院吉林132012

为实现分布式发电系统的无缝切换和提高可再生能源利用,本文提出了一种无破坏性和无有功功率波动的孤岛检测新方法。该方法通过注入周期性无功电流扰动,迫使公共耦合点电压频率出现相对应周期性波动,采用滑模离散傅里叶变换提取频率波... 详细信息

为实现分布式发电系统的无缝切换和提高可再生能源利用,本文提出了一种无破坏性和无有功功率波动的孤岛检测新方法。该方法通过注入周期性无功电流扰动,迫使公共耦合点电压频率出现相对应周期性波动,采用滑模离散傅里叶变换提取频率波动特征分量,根据孤岛发生前后特征分量的变化进行孤岛判别。依IEEE std 1547孤岛测试标准对该方法进行理论分析和仿真研究,结果验证了该方法的有效性。

关键词：孤岛检测周期性无功电流扰动滑动离散傅里叶变换自适应动态阈值

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