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基于POD法控制模态选择的大跨屋盖结构风致动力响应分析 被引量:4
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作者 章李刚 楼文娟 黄铭枫 《浙江大学学报(工学版)》 EI CAS CSCD 北大核心 2012年第9期1599-1604,共6页
为了提高大跨度屋盖结构风致动力响应频域分析的计算效率,提出先挑选控制模态再进行风致响应有效计算的"二步法"过程.将本征正交分解(POD)法和模态叠加法相结合,建立风荷载作用下大跨屋盖结构各阶模态响应的快速估算方法,并... 为了提高大跨度屋盖结构风致动力响应频域分析的计算效率,提出先挑选控制模态再进行风致响应有效计算的"二步法"过程.将本征正交分解(POD)法和模态叠加法相结合,建立风荷载作用下大跨屋盖结构各阶模态响应的快速估算方法,并以估算结果作为衡量准则进行控制模态的挑选;在经过挑选得到控制模态后,采用考虑了荷载空间分布相关性和广义风荷载谱中虚部成分的精确完全二次项组合方法(ACQC)进行风致响应的有效计算.将该方法运用于某大型火车站站台屋盖结构,计算表明:在采用相同的模态参与阶数的条件下,本方法得到的风致响应结果具有更高的精确性和更快的收敛性. 展开更多
关键词 大跨度屋盖结构 频域分析 振动模态选择 模态叠加法 本征正交分解 ACQC
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Depression recognition using functional connectivity based on dynamic causal model
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作者 罗国平 刘刚 +2 位作者 赵竟 姚志剑 卢青 《Journal of Southeast University(English Edition)》 EI CAS 2011年第4期367-369,共3页
Dynamic casual modeling of functional magnetic resonance imaging(fMRI) signals is employed to explore critical emotional neurocircuitry under sad stimuli. The intrinsic model of emotional loops is built on the basis... Dynamic casual modeling of functional magnetic resonance imaging(fMRI) signals is employed to explore critical emotional neurocircuitry under sad stimuli. The intrinsic model of emotional loops is built on the basis of Papez's circuit and related prior knowledge, and then three modulatory connection models are established. In these models, stimuli are placed at different points, which represents they affect the neural activities between brain regions, and these activities are modulated in different ways. Then, the optimal model is selected by Bayesian model comparison. From group analysis, patients' intrinsic and modulatory connections from the anterior cingulate cortex (ACC) to the right inferior frontal gyrus (rlFG) are significantly higher than those of the control group. Then the functional connection parameters of the model are selected as classifier features. The classification accuracy rate from the support vector machine(SVM) classifier is 80.73%, which, to some extent, validates the effectiveness of the regional connectivity parameters for depression recognition and provides a new approach for the clinical diagnosis of depression. 展开更多
关键词 depression recognition FMRI dynamic causal model Bayesian model selection
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