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利用词项语义共现和社团划分发现微博热点事件 被引量:2
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作者 李晓红 孔文文 +1 位作者 马堉垠 马慧芳 《计算机应用研究》 CSCD 北大核心 2020年第5期1336-1339,共4页
针对传统词项之间语义关系抽取难以适用于微博,导致发现微博热点事件不敏感的问题,提出一种基于词项语义共现和社团划分的方法发现热点事件。首先利用热度定义对微博数据进行初次筛选,通过构建共现词项图来模拟词项间的语义相关性,并结... 针对传统词项之间语义关系抽取难以适用于微博,导致发现微博热点事件不敏感的问题,提出一种基于词项语义共现和社团划分的方法发现热点事件。首先利用热度定义对微博数据进行初次筛选,通过构建共现词项图来模拟词项间的语义相关性,并结合修改的TF-IDF公式计算词项间的语义相关度;借助社区划分和模块度的概念对词项图进行划分,完成词项聚类,进而获得热点事件。实验结果表明,与同类方法相比,该方法的准确率较高,发现的热点事件与实时事件基本保持一致,具有较好的热点识别效果。 展开更多
关键词 热度 亲密度 语义相关性 热点事件 共现图 模块度
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Appraisal of arid land status:a holistic assessment pertains to bio-physical indicators and ecosystem values
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作者 Manish Mathur S.Sundaramoorthy 《Ecological Processes》 SCIE EI 2018年第1期487-501,共15页
Background:Appraisal of arid land status is very crucial one to know the extent and factors associated with their degradation.Previous studies from arid regions are mostly qualitative in nature(indicator assessment li... Background:Appraisal of arid land status is very crucial one to know the extent and factors associated with their degradation.Previous studies from arid regions are mostly qualitative in nature(indicator assessment like good,moderate,severe,and very severe)and generally overlooked the significance of temporal fluctuation.Methods:In this study,the temporal status of 12 Indian arid lands was accessed by using a new integrated approach that includes attributes like relative converge score(RCS),herbaceous component score(HCS),soil quality indexModified(SQI),ecosystem monitoring value(EMV),and a modified bare patch index.From each land,data were collected during three seasonal events(pulse,inter-pulse,and non-pulse),and thus,status was evaluated with 36 observations.Data were analyzed by using frequency distribution,principal component analysis(PCA),student t test,and regression technique.Results:RCS and HCS were recorded minimum(0.005,0.65)during non-pulse event and maximum(0.36,1.79)during pulse event respectively.With this approach,multi-directional temporal status of lands identified that were grouped into lower(7),moderate(14),high(12),and very high(3)quality lands.Conclusion:This integrated study suggested that in arid regions,although rainfall triggers plant community composition,however,sole utilization of this parameter is unable to portray the true status of lands,and other physical(soil)and biotic(livestock and other anthropogenic)parameters are equally important and influential during other events. 展开更多
关键词 Vegetation status Relative coverage score Soil quality Land status Ecosystem monitoring value
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