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Biomass crops on marginal lands:Increasing precipitation and mitigating extreme precipitation events
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作者 LU Chunyan HE Yufeng +1 位作者 WANG Suichan LI Zhouyuan 《水利水电技术(中英文)》 北大核心 2026年第4期58-80,共23页
[Objective]With increasing energy demand and growing concerns about climate change,the rational utilization of marginal lands for cultivating biomass energy crops has emerged as a research focus in recent years.Previo... [Objective]With increasing energy demand and growing concerns about climate change,the rational utilization of marginal lands for cultivating biomass energy crops has emerged as a research focus in recent years.Previous studies have demonstrated that cultivating perennial biomass crops on marginal lands significantly impacts regional climate change and food production.However,these investigations did not fully consider the interactive feedback between plant growth and climate change,leading to slightly insufficient reliability of the result.[Methods]To address the limitations of earlier studies,the coupled model CWRF-BioCro was employed to comprehensively consider the interactive feedback between plant growth and climate change,and to analyze changes in regional precipitation patterns and their physical mechanisms under two scenarios in the United States:cultivation of perennial biomass crops on marginal lands and maintenance of existing vegetation cover.[Results]The result showed that after cultivating perennial biomass crops on marginal lands,the regional total average daily precipitation increased by 6.33 mm/day(0.01%),with most of the increase occurring during spring,summer,and autumn in the central and western regions and during autumn and winter in the eastern region.This was primarily due to the significant enhancement of water vapor transport and latent heat flux in the region.The regional maximum daily precipitation decreased by 2.1 mm(4.39%),mainly in the central and eastern regions,Resulting from a significant decrease in sensible heat flux in these regions.Meanwhile,the frequency of precipitation events with an average daily precipitation greater than 50 mm/d decreased in the central and eastern regions,with the most pronounced reduction of 31 days(0.24%)observed in events in the range of 50.0~99.9 mm/day.[Conclusion]In summary,planting perennial biomass crops on marginal lands can increase regional precipitation and reduce extreme precipitation.These findings highlight the critical role of biophysical feedback mechanisms in regulating regional climate and provide a scientific foundation for developing climate-adaptive land management strategies. 展开更多
关键词 biomass crops PRECIPITATION extreme events land use changes climate change grain production vegetation coverage influencing factors
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Analysis of characteristics of heavy rainfall events induced by landfalling tropical cyclones in China from 1980 to 2020
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作者 JI Jie WANG Yanjun +3 位作者 JIANG Tong ZHAI Jianqing SANG Wenwen WU Hailan 《水利水电技术(中英文)》 北大核心 2026年第3期79-90,共12页
[Objective]China is one of the countries most severely affected by heavy rainfall from tropical cyclones,incurring annual economic losses amounting to hundreds of billions of yuan.Understanding the variation character... [Objective]China is one of the countries most severely affected by heavy rainfall from tropical cyclones,incurring annual economic losses amounting to hundreds of billions of yuan.Understanding the variation characteristics of these events is crucial for flood prevention and disaster mitigation efforts.[Methods]Based on hourly rainfall data from 1185 meteorological stations in China and the best track dataset of tropical cyclones,heavy rainfall events were defined using an absolute threshold method.Linear regression was employed to analyze the characteristics of hourly-scale heavy rainfall events induced by landfalling tropical cyclones in China from 1980 to 2020.The analysis focused on the spatiotemporal distribution of these events and the interannual variation trends in frequency,intensity,and duration of events with different durations(short-duration:1~6 h,medium-duration:7~12 h,and long-duration:>12 h).[Results](1)Heavy rainfall events induced by landfalling tropical cyclones mainly occurred in Hainan Island and the southeastern coastal areas of China,with their intensity weakening toward inland and northern areas.The overall intensity of such events showed an increasing trend.The duration of heavy rainfall events tended to decrease from south to north and from coastal to inland areas,with Hainan exhibiting the longest duration(6.22 h/a).Areas with increasing trends in event frequency,intensity,and duration were mainly located along the southern coast,the lower reaches of the Yangtze River,and Shandong Province.(2)In rainfall events induced by landfalling tropical cyclones with different durations,long-duration events accounted for the highest proportion(39.75%)and showed an increasing trend in frequency along with short-duration events.The rainfall intensity of both types was increasing,but the duration of long-duration events continued to rise,while that of short-and medium-duration events was decreasing.[Conclusion]From 1980 to 2020,the intensity of heavy rainfall events induced by landfalling tropical cyclones has increased,and event durations have been prolonged,exerting profound impacts on the socioeconomic development and ecological security in some regions of China.The increasing frequency,intensity,and duration of long-duration heavy rainfall events pose significant challenges for disaster prevention in both coastal and inland areas of the country. 展开更多
关键词 landfalling tropical cyclone rainfall event spatiotemporal distribution temporal trend DURATION precipitation intensity influencing factors
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Discrimination of mining microseismic events and blasts using convolutional neural networks and original waveform 被引量:26
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作者 DONG Long-jun TANG Zheng +2 位作者 LI Xi-bing CHEN Yong-chao XUE Jin-chun 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第10期3078-3089,共12页
Microseismic monitoring system is one of the effective methods for deep mining geo-stress monitoring.The principle of microseismic monitoring system is to analyze the mechanical parameters contained in microseismic ev... Microseismic monitoring system is one of the effective methods for deep mining geo-stress monitoring.The principle of microseismic monitoring system is to analyze the mechanical parameters contained in microseismic events for providing accurate information of rockmass.The accurate identification of microseismic events and blasts determines the timeliness and accuracy of early warning of microseismic monitoring technology.An image identification model based on Convolutional Neural Network(CNN)is established in this paper for the seismic waveforms of microseismic events and blasts.Firstly,the training set,test set,and validation set are collected,which are composed of 5250,1500,and 750 seismic waveforms of microseismic events and blasts,respectively.The classified data sets are preprocessed and input into the constructed CNN in CPU mode for training.Results show that the accuracies of microseismic events and blasts are 99.46%and 99.33%in the test set,respectively.The accuracies of microseismic events and blasts are 100%and 98.13%in the validation set,respectively.The proposed method gives superior performance when compared with existed methods.The accuracies of models using logistic regression and artificial neural network(ANN)based on the same data set are 54.43%and 67.9%in the test set,respectively.Then,the ROC curves of the three models are obtained and compared,which show that the CNN gives an absolute advantage in this classification model when the original seismic waveform are used in training the model.It not only decreases the influence of individual differences in experience,but also removes the errors induced by source and waveform parameters.It is proved that the established discriminant method improves the efficiency and accuracy of microseismic data processing for monitoring rock instability and seismicity. 展开更多
关键词 microseismic monitoring waveform classification microseismic events BLASTS convolutional neural network
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Multi-scale regionalization based mining of spatio-temporal teleconnection patterns between anomalous sea and land climate events
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作者 XU Feng SHI Yan +3 位作者 DENG Min GONG Jian-ya LIU Qi-liang JIN Rui 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第10期2438-2448,共11页
Climate sequences can be applied to defining sensitive climate zones, and then the mining of spatio-temporal teleconnection patterns is useful for learning from the past and preparing for the future. However, scale-de... Climate sequences can be applied to defining sensitive climate zones, and then the mining of spatio-temporal teleconnection patterns is useful for learning from the past and preparing for the future. However, scale-dependency in this kind of pattern is still not well handled by existing work. Therefore, in this study, the multi-scale regionalization is embedded into the spatio-temporal teleconnection pattern mining between anomalous sea and land climatic events. A modified scale-space clustering algorithm is first developed to group climate sequences into multi-scale climate zones. Then, scale variance analysis method is employed to identify climate zones at characteristic scales, indicating the main characteristics of geographical phenomena. Finally, by using the climate zones identified at characteristic scales, a time association rule mining algorithm based on sliding time windows is employed to discover spatio-temporal teleconnection patterns. Experiments on sea surface temperature, sea level pressure, land precipitation and land temperature datasets show that many patterns obtained by the multi-scale approach are coincident with prior knowledge, indicating that this method is effective and reasonable. In addition, some unknown teleconnection patterns discovered from the multi-scale approach can be further used to guide the prediction of land climate. 展开更多
关键词 CLIMATE sequences ANOMALOUS climatic events SPATIO-TEMPORAL teleconnection patterns MULTI-SCALE REGIONALIZATION
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Non-obstructive coronary artery disease and cardiovascular events in patients with angina-like chest pain detected by coronary angiography:a Chinese cohort study
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作者 Huiwen Zhang Xi Zhao +3 位作者 Yuanlin Guo Naqiong Wu Chenggang Zhu Jianjun Li 《中国循环杂志》 CSCD 北大核心 2018年第S01期145-145,共1页
Objective The utility of non-obstructive coronary artery diseases(NOCAD) in cardiovascular events (CVE) among Chinese patients has less been evaluated. Our objective was to investigate the prognostic value of NOCAD in... Objective The utility of non-obstructive coronary artery diseases(NOCAD) in cardiovascular events (CVE) among Chinese patients has less been evaluated. Our objective was to investigate the prognostic value of NOCAD in patients with angina-like chest pain detected by coronary angiography (CAG) in a large Chinese cohort study. 展开更多
关键词 NON-OBSTRUCTIVE CORONARY artery diseases cardiovascular events CORONARY ANGIOGRAPHY
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Modeling of unsupervised knowledge graph of events based on mutual information among neighbor domains and sparse representation
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作者 Jing-Tao Sun Jing-Ming Li Qiu-Yu Zhang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2022年第12期2150-2159,共10页
Text event mining,as an indispensable method of text mining processing,has attracted the extensive attention of researchers.A modeling method for knowledge graph of events based on mutual information among neighbor do... Text event mining,as an indispensable method of text mining processing,has attracted the extensive attention of researchers.A modeling method for knowledge graph of events based on mutual information among neighbor domains and sparse representation is proposed in this paper,i.e.UKGE-MS.Specifically,UKGE-MS can improve the existing text mining technology's ability of understanding and discovering high-dimensional unmarked information,and solves the problems of traditional unsupervised feature selection methods,which only focus on selecting features from a global perspective and ignoring the impact of local connection of samples.Firstly,considering the influence of local information of samples in feature correlation evaluation,a feature clustering algorithm based on average neighborhood mutual information is proposed,and the feature clusters with certain event correlation are obtained;Secondly,an unsupervised feature selection method based on the high-order correlation of multi-dimensional statistical data is designed by combining the dimension reduction advantage of local linear embedding algorithm and the feature selection ability of sparse representation,so as to enhance the generalization ability of the selected feature items.Finally,the events knowledge graph is constructed by means of sparse representation and l1 norm.Extensive experiments are carried out on five real datasets and synthetic datasets,and the UKGE-MS are compared with five corresponding algorithms.The experimental results show that UKGE-MS is better than the traditional method in event clustering and feature selection,and has some advantages over other methods in text event recognition and discovery. 展开更多
关键词 Text event mining Knowledge graph of events Mutual information among neighbor domains Sparse representation
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Extreme air pollution events:Modeling and prediction
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作者 周松梅 邓启红 刘蔚巍 《Journal of Central South University》 SCIE EI CAS 2012年第6期1668-1672,共5页
In order to get prepared for the coming extreme pollution events and minimize their harmful impacts, the first and most important step is to predict their possible intensity in the future. Firstly, the generalized Par... In order to get prepared for the coming extreme pollution events and minimize their harmful impacts, the first and most important step is to predict their possible intensity in the future. Firstly, the generalized Pareto distribution (GPD) in extreme value theory was used to fit the extreme pollution concentrations of three main pollutants: PM10, NO2 and SO:, from 2005 to 2010 in Changsha, China. Secondly, the prediction results were compared with actual data by a scatter plot. Four statistical indicators: EMA (mean absolute error), ERMS (root mean square error), IA (index of agreement) and R2 (coefficient of determination) were used to evaluate the goodness-of-fit as well. Thirdly, the return levels corresponding to different return periods were calculated by the fitted distributions. The fitting results show that the distribution of PM10 and SO2 belongs to exponential distribution with a short tail while that of the NOe belongs to beta distribution with a bounded tail. The scatter plot and four statistical indicators suggest that GPD agrees well with the actual data. Therefore, the fitted distribution is reliable to predict the return levels corresponding to different return periods. The predicted return levels suggest that the intensity of coming pollution events for PM10 and SO2 will be even worse in the future, which means people have to get enough preparation for them. 展开更多
关键词 extreme pollution event generalized Pareto distribution return level return period
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Association of ITGA2 dual site variants with recurrent ischemic events in patients undergoing stenting for symptomatic intracranial atherosclerotic stenosis
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作者 Dong Yiwen Ye Jiadan +6 位作者 Cheng Sheng Yang Hongge Li Ze Di Xuan Lou Xin Li Xingang Ma Ning 《首都医科大学学报》 2026年第3期408-416,共9页
Objective To investigate the correlation between gene polymorphisms and the occurrence of adverse clinical events following dual antiplatelet therapy in patients with symptomatic intracranial atherosclerotic stenosis.... Objective To investigate the correlation between gene polymorphisms and the occurrence of adverse clinical events following dual antiplatelet therapy in patients with symptomatic intracranial atherosclerotic stenosis.Methods A total of 195 patients were enrolled and categorized into 32 cases(those with clinical adverse events)and 163 controls(without events).Genotyping of 20 single nucleotide polymorphism(SNP)from 17 genes was executed.To address the imbalance in sample size between cases(n=32)and controls(n=163),weighted Logistic regression analysis was performed using frequency weights based on the reciprocal of group proportions.Weights were calculated to account for the unequal case-control ratio and improve the stability and reliability of regression estimates.Results The ITGA2 rs1126643(C807T)and rs1062535(G873A)polymorphisms were significantly correlated with adverse clinical events.Specifically,the mutant frequency of allele C(ITGA2 rs1126643)and allele G(ITGA2 rs1062535)was significantly higher in cases compared to controls(OR=2.97,95%CI:1.702-5.172,P=0.0001;OR=3.27,95%CI:1.762-6.066,P=0.0002,respectively).Other genotypes showed no significant differences between the groups.Conclusion The ITGA2 C807T and G873A polymorphisms are associated with an increased risk of recurrent ischemic events in Chinese patients with symptomatic intracranial atherosclerotic stenosis after stenting.Detection of these variants may help identify individuals at high risk of recurrent ischemic events in this specific population. 展开更多
关键词 intracranial atherosclerotic stenosis ischemic events dual antiplatelet therapy single nucleotide polymorphism genetic markers ITGA2
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基于Event模型的城市物流无人机同高度交叉运行间隔研究 被引量:2
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作者 张健 赵嶷飞 +2 位作者 卢飞 黎宗孝 罗鑫悦 《中国安全科学学报》 北大核心 2025年第5期99-105,共7页
为解决城市物流无人机飞行流量加大、隔离航线模式空域利用率低的矛盾,需要实施安全有效的交叉运行。通过研究交叉运行碰撞风险,确定侧向误差、垂直误差、纵向临近率等核心参数,构建同高度交叉运行间隔模型。在此基础上,进一步考虑机载... 为解决城市物流无人机飞行流量加大、隔离航线模式空域利用率低的矛盾,需要实施安全有效的交叉运行。通过研究交叉运行碰撞风险,确定侧向误差、垂直误差、纵向临近率等核心参数,构建同高度交叉运行间隔模型。在此基础上,进一步考虑机载冲突探测与解脱(CDR)系统失效问题,并运用事件树分析方法,提出并构建城市物流无人机交叉间隔综合模型。结果表明:在航线夹角为60°情况下,对标安全目标水平1.5×10^(-8),所需交叉间隔为158 m;对标安全目标水平1×10^(-6),所需交叉间隔155 m。随着交叉角度增大,运行间隔总体呈现上升趋势,当接近180°时,即对头运行时,所需间隔急剧上升,与实际认知一致。 展开更多
关键词 Event模型 城市物流无人机(UAV) 同高度 交叉运行 交叉间隔 冲突探测与解脱(CDR)
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基于相似准则的林业无土栽培基质混合分析 被引量:1
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作者 沈嵘枫 钟文斌 +3 位作者 王沅栋 黄俊疆 张文悦 杨诗嘉 《森林工程》 北大核心 2025年第5期1034-1041,共8页
针对无土栽培基质生产过程中基质混合不充分和采用离散元法时因模型过大、颗粒数过多而导致仿真结果不精确的问题,通过建立相似理论搅拌模型,利用赫兹-明德林(无滑移)模型(Hertz-Mindlin(no slip))建立肥料与土壤颗粒仿真模型,对影响混... 针对无土栽培基质生产过程中基质混合不充分和采用离散元法时因模型过大、颗粒数过多而导致仿真结果不精确的问题,通过建立相似理论搅拌模型,利用赫兹-明德林(无滑移)模型(Hertz-Mindlin(no slip))建立肥料与土壤颗粒仿真模型,对影响混合器搅拌均匀性和效率的放料方式、搅拌式混合器叶片间距和搅拌器转速3个变量因素进行离散元仿真分析。结果表明,相似理论搅拌模型可用于仿真模型的缩放,达到减少计算量,提高仿真精度的效果;采用平铺的放料方式,由于上层颗粒会在重力的作用下加速颗粒间的混合,混合效果更佳;相似模型中叶片间较佳间距为20 mm;叶片转速在50 r/min时搅拌混合效果和经济性最佳;与人工搅拌相比,搅拌式混合器大大提高了混合效率和效果,且可以避免出现盲区。仿真分析结果可为搅拌式混合器的设计与优化提供理论参考。 展开更多
关键词 育苗基质 搅拌装置 相似准则 离散元分析 Event driven execution manager(EDEM)离散元仿真软件
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奥陶纪-志留纪边界附近火山活动记录:来华南周缘钾质斑脱岩的信息 被引量:55
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作者 胡艳华 孙卫东 +3 位作者 丁兴 汪方跃 凌明星 刘健 《岩石学报》 SCIE EI CAS CSCD 北大核心 2009年第12期3298-3308,共11页
扬子地台内奥陶纪顶部的五峰组到志留纪底部的龙马溪组间存在着多个粘土岩层。前人研究结果认为这些粘土岩层为钾质斑脱岩,是火山喷发的凝灰质物质在海相环境沉积、蚀变的产物。这些斑脱岩广泛分布于扬子地台周缘,对理解奥陶纪-志留纪... 扬子地台内奥陶纪顶部的五峰组到志留纪底部的龙马溪组间存在着多个粘土岩层。前人研究结果认为这些粘土岩层为钾质斑脱岩,是火山喷发的凝灰质物质在海相环境沉积、蚀变的产物。这些斑脱岩广泛分布于扬子地台周缘,对理解奥陶纪-志留纪时华南所处的大地构造位置和相应的构造事件具有重要的意义。本文对采自扬子地台内湖北宜昌地区和贵州桐梓地区奥陶纪-志留纪界线剖面的斑脱岩层进行了矿物学及地球化学工作,旨在判定其形成的构造环境。矿物学研究表明上述岩石除了含有粘土矿物外,还含有石英、长石、黑云母、磷灰石、锆石等中酸性岩浆岩中的常见矿物,属典型的钾质斑脱岩。本文利用在风化过程中不活动元素对斑脱岩的原岩进行了恢复,结果也表明其原岩为中酸性火山岩,包括安山岩-英安岩-及流绞岩等。微量元素特征显示多数样品具有典型的岛弧火山岩的特征,很可能与北面早古生代秦岭洋的闭合过程中的板块俯冲有关,也可能是早古生代在华南板块东南缘外侧存在的一古老洋壳向华南板块的俯冲。有一个样品(YC0711)没有Nb的负异常,但是具有明显的Ti负异常,在Th/Yb-Nb/Yb判别图上落在岛弧区附近,其原岩可能是富铌玄武岩之类的特殊岛弧岩石。火山活动的峰期为晚奥陶世赫南特阶时代,与地质历史上第二大的生物大灭绝事件同时。前人认为该生物灭绝事件与冈瓦纳冰川有关。考虑到华南以及欧洲、北美等地均出现大规模晚奥陶世-早侏罗纪钾质斑脱岩,奥陶纪-志留纪边界的火山事件是具有全球规模的,所喷发的岩石多是富含挥发份的中酸性岩,对大气圈和生物圈具有十分重要的影响,本文认为火山活动很可能是造成晚奥陶世的生物大灭绝事件和冈瓦纳冰川的主要诱导因素。 展开更多
关键词 奥陶纪 志留纪 边界 火山活动 活动记录 华南板块 钾质斑脱岩 信息 Yangtze Block mass extinction VOLCANIC rocks 扬子地台 晚奥陶世 typical characteristics South China plate tectonic setting 事件 生物大灭绝 VOLCANIC activity geological events
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山西代县金红石矿床中锆石的内部特征和矿物包裹体研究及其地质意义 被引量:6
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作者 徐永婧 庞尔成 +4 位作者 施光海 刘成林 刘琰 吴振 李孔亮 《岩石学报》 SCIE EI CAS CSCD 北大核心 2009年第12期3422-3430,共9页
对山西代县洪塘矿区富含红色和黑色两种金红石的直闪岩进行岩相观察和矿物成分分析,并就其中锆石在阴极发光下的外部形态、内部结构及矿物包裹体进行研究。所分选出的锆石按其颗粒上的相对位置、形态、阴极发光图像、SHRIMP年龄值以及... 对山西代县洪塘矿区富含红色和黑色两种金红石的直闪岩进行岩相观察和矿物成分分析,并就其中锆石在阴极发光下的外部形态、内部结构及矿物包裹体进行研究。所分选出的锆石按其颗粒上的相对位置、形态、阴极发光图像、SHRIMP年龄值以及内部矿物包裹体划分为复杂锆石和单成因锆石,其中复杂锆石由核部、幔部和边部锆石三类锆石组成。第Ⅰ类锆石无环带,部分边缘可见溶蚀痕迹,为继承锆石。内部包裹富镁矿物组合顽火辉石+金云母,与寄主岩石的组合明显不同,反映其可能是寄主岩石形成之前保留于锆石中的原岩矿物并源于地幔。第Ⅱ类锆石为半自形-自形晶,环带较宽且清晰,推测为高级变质锆石。其内矿物包裹体主要为直闪石,其次为钙铁辉石(?),反映其形成于角闪岩相,与寄主岩石的矿物组合可能一致。第Ⅲ类锆石主要位于增生边,阴极发光亮度高,推测为流体改造的变质锆石。第Ⅳ类单成因锆石多呈自形,阴极发光下较暗,生长环带规则且较窄。矿物包裹体有钠长石+石英+白云母,对应中压绿片岩相,其形成温度和压力低于寄主岩石,它与第Ⅲ类锆石可能是在同一期后期事件中形成。结合岩相学研究结果,认为该区金红石矿床之原岩可能是岩浆岩,后期经历了至少两期构造热事件,早期热事件可能导致了锆石内U-Th-Pb体系的重置。以上研究结果表明经历复杂变质作用的变质岩中锆石内部矿物包裹体的研究分析还是探讨寄主岩石成因及所经历地质事件的有效手段。 展开更多
关键词 山西代县 金红石矿床 变质锆石 特征和 矿物包裹体 地质意义 mineral Study host rock 阴极发光 Type 岩石 寄主 high grade metamorphic rocks geological events 岩相 热事件 矿物组合 thermal events
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终端区有人/无人融合运行进场排序调度方法
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作者 周千容 邵荃 郭曹卓尔 《科学技术与工程》 北大核心 2025年第26期11388-11397,共10页
为研究无人驾驶航空器与有人驾驶航空器终端区融合运行的问题,针对无人机的数据链路延迟特性,结合尾流因素、通信、导航和监视误差,建立了改进的Event空中碰撞模型计算有人/无人运行间隔,以延误和效率为目标建立终端区进场航班排序与调... 为研究无人驾驶航空器与有人驾驶航空器终端区融合运行的问题,针对无人机的数据链路延迟特性,结合尾流因素、通信、导航和监视误差,建立了改进的Event空中碰撞模型计算有人/无人运行间隔,以延误和效率为目标建立终端区进场航班排序与调度的模型,设计基于滑动时间窗的精英保留策略的自适应快速非支配排序遗传算法(RHC-NSGA-Ⅱ),计算进场航班排序与调度的最优解。研究对象选取轻型、中型和重型机作为组合,求解满足ICAO提出的安全目标水平的纵向安全运行间隔,通过某机场的实际运行数据采用改进的算法对进场航班排序与调度模型进行验证。仿真结果表明,改进的NSGA-Ⅱ方法相较于NSGA-Ⅱ算法,算法性能更优越,求解的效率更高;针对大规模数据集,对比25%混合度的有人/无人运行和50%混合度的有人/无人运行,总延误时间和平均延误时间相对于传统有人机运行都提高了0.6%,总飞行时间和最大飞行时间则分别降低了1.32%、0.96%。 展开更多
关键词 空中交通管理 多目标优化 融合运行 Event模型 终端区
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公民意识的觉醒——《穹顶之下》引发的热议 被引量:2
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作者 张祖群 《电影评介》 北大核心 2015年第4期1-6,共6页
一、环保纪录片的里程碑关于环保的纪录片多是欧美发达国家拍摄的,例如:《可爱的动物(Animals Are Beautiful People)》(1974,南非)、《野鸟世界(The Life of Birds)》(1998,英国)、《地球公民(Earthlings)》(2005,美国)、《地球脉动(Pl... 一、环保纪录片的里程碑关于环保的纪录片多是欧美发达国家拍摄的,例如:《可爱的动物(Animals Are Beautiful People)》(1974,南非)、《野鸟世界(The Life of Birds)》(1998,英国)、《地球公民(Earthlings)》(2005,美国)、《地球脉动(Planet Earth)》(2006,英国)、《难以忽视的真相(An Inconvenient Truth)》(2006,美国)、《危险中的星球(Planet in Peril)》(2007,美国)、《自然界大事件(Nature’s Great Events)》(2009,英国)、《人类星球(Human Planet)》(2011,英国)、《家园(Home)》(2011, 展开更多
关键词 地球脉动 大事件 柴静 TRUTH events 公众利益 污染治理 公众媒体 全国环境保护 大排量
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浅地层剖面交互拾取解释技术研究 被引量:10
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作者 丁维凤 罗进华 +2 位作者 来向华 苟铮慷 傅晓明 《海洋科学》 CAS CSCD 北大核心 2008年第9期1-6,共6页
浅地层剖面探测在海洋学研究与海洋工程调查中使用愈来愈频繁,剖面资料的解释工作变得越来越繁重、因浅地层剖面实际解释工作的需要,结合浅地层剖面资料的特点,研究并实现了剖面反射层位的自动拾取、利用 Event 号交互拾取特征点、等 Pi... 浅地层剖面探测在海洋学研究与海洋工程调查中使用愈来愈频繁,剖面资料的解释工作变得越来越繁重、因浅地层剖面实际解释工作的需要,结合浅地层剖面资料的特点,研究并实现了剖面反射层位的自动拾取、利用 Event 号交互拾取特征点、等 Ping 间隔拾取、求取海底下反射层位厚度等解释功能,这些解释功能的实现加快了剖面解释工作的进度,提高了解释结果的精度,并在实际浅地层剖面资料解释工作中取得了良好的应用效果。 展开更多
关键词 浅地层剖面 交互拾取 Event定位号 等Ping间隔拾取 反射层厚度
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自由飞行下改进的Event碰撞风险计算模型 被引量:14
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作者 张兆宁 时瑞军 《中国安全科学学报》 CAS CSCD 北大核心 2015年第7期35-40,共6页
为确保航空器在自由飞行空域中安全飞行,需要建立自由飞行下的碰撞风险计算模型,评估其碰撞风险。借鉴非自由飞行下的Event碰撞风险评估模型构想,根据自由飞行的特点,将碰撞模版由长方体改为球体。在自由飞行环境下,碰撞风险由航空器航... 为确保航空器在自由飞行空域中安全飞行,需要建立自由飞行下的碰撞风险计算模型,评估其碰撞风险。借鉴非自由飞行下的Event碰撞风险评估模型构想,根据自由飞行的特点,将碰撞模版由长方体改为球体。在自由飞行环境下,碰撞风险由航空器航向关系及航空器间距共同确定,并考虑通信、导航、监视(CNS)技术因素对航空器定位误差的影响;分析航向解脱和高度解脱2种冲突解脱方式,建立碰撞风险模型;利用Matlab对模型进行求解,最后依据碰撞风险计算结果确定最小安全间距。算例结果表明,目标安全水平(TSL)为1.5×10^(-8)(次/飞行小时)时,航空器间最小安全间距为10 096 m,与实际相符。 展开更多
关键词 自由飞行 目标安全水平(TSL) 冲突解脱 碰撞风险 最小安全间距 Event模型
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典型通用事件语义模型比较分析研究 被引量:9
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作者 陈金菊 欧石燕 林泽斐 《现代情报》 CSSCI 2021年第2期55-64,77,共11页
[目的/意义]事件语义模型是描述和组织事件内容的语义框架。对事件语义模型进行总结和剖析,可为相关研究提供参考。[方法/过程]文章梳理总结了7个典型通用事件语义模型(Event、SEM、LODE、ABC、LODE、EBSTDM和刘宗田等提出的事件语义模... [目的/意义]事件语义模型是描述和组织事件内容的语义框架。对事件语义模型进行总结和剖析,可为相关研究提供参考。[方法/过程]文章梳理总结了7个典型通用事件语义模型(Event、SEM、LODE、ABC、LODE、EBSTDM和刘宗田等提出的事件语义模型),并从其特点和应用领域等方面进行详细比较分析。[结果/结论]展望了事件语义模型的发展趋势,包括开发新的语义表示维度和建模视角;事件语义模型的横向连续性和纵向层次化相结合的研究;事件语义模型动态特征的语义组织研究。 展开更多
关键词 事件语义模型 语义维度 动态性 连续性 语义组织 EVENT SEM LODE ABC EB-STDM 刘宗田等提出的事件语义模型
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基于ADS-B监视技术的飞行器纵向最小间隔研究 被引量:6
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作者 吴学礼 霍佳楠 张建华 《河北科技大学学报》 CAS 2017年第1期52-58,共7页
为解决航路飞行安全问题,提高碰撞风险检测的精确度,主要研究飞行器在平行航路飞行过程中纵向安全间隔的问题。对传统的EVENT碰撞模型进行改进,建立以椭圆柱体为碰撞模板的EVENT模型。介绍了广播式自动相关监视(ADS-B)技术的性能及应用... 为解决航路飞行安全问题,提高碰撞风险检测的精确度,主要研究飞行器在平行航路飞行过程中纵向安全间隔的问题。对传统的EVENT碰撞模型进行改进,建立以椭圆柱体为碰撞模板的EVENT模型。介绍了广播式自动相关监视(ADS-B)技术的性能及应用背景,并在改进EVENT模型基础上提出基于ADS-B监视技术下各个参数的计算方法。以中航工业石家庄飞机工业有限责任公司小鹰500机型为模型算例,计算出其最小安全间隔。研究结果符合国际民航组织的飞行安全指标,可为研究基于ADS-B监视技术的风险分级提供一种有效方法。 展开更多
关键词 安全信息工程 ADS-B 椭圆柱体碰撞盒 EVENT模型 碰撞风险 纵向间隔
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MULTI-PERIODIC COLLISIONAL PROCESS BETWEEN INDIAN AND ASIAN CONTINENTS:A CASE OF EASTERN HIMALAYAN SYNTAXIS AND HENGDUAN MOUNTAINS 被引量:6
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作者 Zhong Dalai 1, Ding Lin 1, Zhang Jinjiang 1, Ji Jianqing 2(1 Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 2 Department of Geology, Peking University, Beijing 100871, China) 《地学前缘》 EI CAS CSCD 2000年第S1期47-48,共2页
Our study area covered the Eastern Himalayan Syntaxis (EHS) and its southern extension (Hengduan Mountain or western Sichuan and Yunnan (WSY)) which is located at the orthogonal and oblique collisional front between I... Our study area covered the Eastern Himalayan Syntaxis (EHS) and its southern extension (Hengduan Mountain or western Sichuan and Yunnan (WSY)) which is located at the orthogonal and oblique collisional front between Indian and Asian continents during Cenozoic.Based on geometric and kinematic mapping of the major boundary or regional faults (Dongjug—Mainling(1), Anigiao(2) and Jali(3), Guyu(4) faults in EHS, Ailaoshan—Red River(5), Lancangjiang(6), Gaoligong(7), Binlangjiang(8) and Magok(9) faults in WSY) (see Fig.1), especially on abundant geochronological dating of the mylonitic rocks along these faults, and coupled with magmato\|metamorphic sequences of this region, we try to deal with the temporal and spatial relationships of collisional process to answer questions such as: (1) when did collision start ? (2) is thrusting as a initial and dominant deformation mode to absorb the crustal shortening after suturing, or earlier thrusting usually followed by large\|scale strike\|slip faults? (3) are the two structural patterns coeval at times, or do they occur alternatively during deformation history? (4) are the collisional and associate uplift processes a continuous one or periodic? Insight into such questions is crucial for better understanding of the continental deformation and testing the models available or constraining a new one. 展开更多
关键词 COLLISIONAL PROCESS multi\|period TECTONIC events Eastern HIMALAYA
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基于模型的开发方法在多应用智能卡中的应用 被引量:2
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作者 章玥 郭建 朱晓冉 《信息网络安全》 2013年第12期75-79,共5页
安全性、可靠性是嵌入式软件的重要性质。为了更好地保证开发的嵌入式软件是可靠和安全的,提出了一种基于模型的开发方法学,包括提炼需求、建立抽象模型及逐层精化三个步骤。首先从环境、功能、性质三个主要方面提取需求,同时明确层次... 安全性、可靠性是嵌入式软件的重要性质。为了更好地保证开发的嵌入式软件是可靠和安全的,提出了一种基于模型的开发方法学,包括提炼需求、建立抽象模型及逐层精化三个步骤。首先从环境、功能、性质三个主要方面提取需求,同时明确层次化的精化策略;然后利用形式化方法建立抽象模型并对该模型进行形式化验证,在正确的抽象模型上逐层精化,并对每层模型进行验证;最后,基于满足需求的模型,进一步利用工具完成代码自动生成。该方法从抽象到具体,以逐层递增的方式明确被开发系统的需求及性质,进行形式化建模,通过反馈机制确保模型的正确性及可用性。为了证明该方法学的可行性,文章以多应用智能卡为开发实例,基于Event-B方法及Rodin平台给出了实际建模及证明的过程和结果。 展开更多
关键词 智能卡 Event—B 形式化方法 定理证明
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