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基于向量自回归模型的微博隐式话题流行度预测 被引量:1
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作者 段东圣 李鹏霄 +1 位作者 李玉华 李瑞轩 《模式识别与人工智能》 EI CSCD 北大核心 2016年第7期616-624,共9页
现有话题流行度预测方法仅基于话题本身的特征进行流行度预测,未考虑不同话题间的相关性.然而在微博上下文不同的话题之间存在一定的相关性,特别是在同一个事件的不同话题之间.因此,文中利用动态话题模型探测微博中的隐式话题及其流行... 现有话题流行度预测方法仅基于话题本身的特征进行流行度预测,未考虑不同话题间的相关性.然而在微博上下文不同的话题之间存在一定的相关性,特别是在同一个事件的不同话题之间.因此,文中利用动态话题模型探测微博中的隐式话题及其流行度时间序列,通过Jensen-Shannon散度和皮尔逊相关系数分别分析话题间的内容和时序相关度,然后在预测模型中引入话题时序相关性,提出基于向量自回归模型的微博隐式话题流行度预测算法.通过在真实微博数据上的实验分析可知,相比未考虑话题相关性的算法,文中算法具有更高的预测准确率和更好的模型拟合效果. 展开更多
关键词 流行度预测 向量自回归(VAR) 微博隐式话题 时序相关度 动态话题模型(DTM)
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MULTIVARIATE ABSOLUTE DEGREE OF GREY INCIDENCE BASED ON DISTRIBUTION CHARACTERISTICS OF POINTS
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作者 张可 王岩 +1 位作者 辛江慧 许叶军 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2012年第2期145-151,共7页
The analysis result of absolute degree of grey incidence for multivariate time series is often inconsistent with the qualitative analysis. To overcome this shortage, a multivariate absolute degree of grey incidence ba... The analysis result of absolute degree of grey incidence for multivariate time series is often inconsistent with the qualitative analysis. To overcome this shortage, a multivariate absolute degree of grey incidence based on distribution characteristics of points is proposed. Based on the geometric description of multivariate time se- ries, the neighborhood extrema are extracted in the different regions, and a characteristic point set is constructed. Then according to the distribution of the characteristic point set, a characteristic point sequence reflecting the ge- ometric features of multivariate time series is obtained. The incidence analysis between multivariate time series is transformed into the relational analysis between characteristic point sequences, and a grey incidence model is established. The model possesses the properties of translational invariance, transpose and rank transform invari- ance, and satisfies the grey incidence analysis axioms. Finally, two cases are studied and the results prove the ef- fectiveness of the model. 展开更多
关键词 grey system absolute degree of grey incidences multivariate time series similarity measure
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Effects of Colored Noise on Periodic Orbits in a One-Dimensional Map
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作者 李丰果 艾保全 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第6期1001-1006,共6页
Noise can induce inverse period-doubling transition and chaos. The effects of the colored noise on periodic orbits, of the different periodic sequences in the logistic map, are investigated. It is found that the dynam... Noise can induce inverse period-doubling transition and chaos. The effects of the colored noise on periodic orbits, of the different periodic sequences in the logistic map, are investigated. It is found that the dynamical behaviors of the orbits, induced by an exponentially correlated colored noise, are different in the mergence of transition, and the effects of the noise intensity on their dynamical behaviors are different from the effects of the correlation time of noise. Remarkably, the noise can induce new periodic orbits, namely, two new orbits emerge in the period-four sequence at the bifurcation parameter value μ = 3.5, four new orbits in the period-eight sequence at μ= 3.55, and three new orbits in the period-six sequence at μ = 3.846, respectively. Moreover, the dynamical behaviors of the new orbits clearly show the resonancelike response to the colored noise. 展开更多
关键词 a one-dimensional map colored noise periodic sequences stochastic resonance
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