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粗糙有限状态机的可恢复性与连通性 被引量:1
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作者 杨京开 《数学的实践与认识》 CSCD 北大核心 2014年第3期255-261,共7页
利用代数的方法研究了粗糙有限状态机的可恢复性与连通性,通过前驱与后继的关系,给出了粗糙有限状态机的可恢复性、连通性与可分离性的一些刻画,讨论了粗糙有限状态机的一些基本性质.
关键词 粗糙有限状态机 可恢复性 连通性 可分离性
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Identification of Cognitive Dysfunction in Patients with T2DM Using Whole Brain Functional Connectivity 被引量:6
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作者 Zhenyu Liu Jiangang Liu +7 位作者 Huijuan Yuan Taiyuan Liu Xingwei Cui Zhenchao Tang Yang Du Meiyun Wang Yusong Lin Jie Tian 《Genomics, Proteomics & Bioinformatics》 SCIE CAS CSCD 2019年第4期441-452,共12页
Majority of type 2 diabetes mellitus(T2DM)patients are highly susceptible to several forms of cognitive impairments,particularly dementia.However,the underlying neural mechanism of these cognitive impairments remains ... Majority of type 2 diabetes mellitus(T2DM)patients are highly susceptible to several forms of cognitive impairments,particularly dementia.However,the underlying neural mechanism of these cognitive impairments remains unclear.We aimed to investigate the correlation between whole brain resting state functional connections(RSFCs)and the cognitive status in 95 patients with T2DM.We constructed an elastic net model to estimate the Montreal Cognitive Assessment(MoCA)scores,which served as an index of the cognitive status of the patients,and to select the RSFCs for further prediction.Subsequently,we utilized a machine learning technique to evaluate the discriminative ability of the connectivity pattern associated with the selected RSFCs.The estimated and chronological MoCA scores were significantly correlated with R=0.81 and the mean absolute error(MAE)=1.20.Additionally,cognitive impairments of patients with T2DM can be identified using the RSFC pattern with classification accuracy of 90.54%and the area under the receiver operating characteristic(ROC)curve(AUC)of 0.9737.This connectivity pattern not only included the connections between regions within the default mode network(DMN),but also the functional connectivity between the task-positive networks and the DMN,as well as those within the task-positive networks.The results suggest that an RSFC pattern could be regarded as a potential biomarker to identify the cognitive status of patients with T2DM. 展开更多
关键词 Type 2 diabetes mellitus Resting state functional connectivity Elastic net Support vector machines MOCA
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基于行业关联网络的中国系统性风险监控防范研究 被引量:12
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作者 李政 刘浩杰 袁晨曦 《国际金融研究》 CSSCI 北大核心 2022年第5期75-86,共12页
本文从行业关联网络视角出发,以中国经济领域中各行业为研究对象,采用基于QVAR模型的溢出指数,捕捉不同冲击规模及方向下的行业间溢出效应,并提出相对溢出指数,考察从正常状态到极端状态下行业间溢出水平及结构变化。研究发现:第一,基于... 本文从行业关联网络视角出发,以中国经济领域中各行业为研究对象,采用基于QVAR模型的溢出指数,捕捉不同冲击规模及方向下的行业间溢出效应,并提出相对溢出指数,考察从正常状态到极端状态下行业间溢出水平及结构变化。研究发现:第一,基于QVAR模型的溢出指数能够较好地捕捉不同冲击规模及方向下行业间的溢出效应,基于条件均值的溢出指数可能错判行业间真实的溢出水平。第二,行业间溢出效应在极端上升和下降状态下呈现非对称性,左尾的总溢出、十个行业的溢入均高于右尾。第三,与正常状态相比,两种极端状态下金融、房地产、能源、医疗保健四个行业的方向性溢出水平显著上升,并且金融的溢入、溢出水平上升幅度最高。第四,在极端上升和下降状态下,金融对医疗保健的定向溢出水平上升幅度最高。 展开更多
关键词 系统性风险 行业关联 基于QVAR模型的溢出指数 极端状态
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Application of Connection in Molecular Dynamics
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作者 Xin Sun 《Communications in Theoretical Physics》 SCIE CAS CSCD 2018年第3期308-310,共3页
The evolution of electronic states in molecule has two origins: dynamical one produced by Schr¨odinger equation and kinematical one caused by base transformation due to nuclear motion.In current theories,the form... The evolution of electronic states in molecule has two origins: dynamical one produced by Schr¨odinger equation and kinematical one caused by base transformation due to nuclear motion.In current theories,the former gets analytic expression; the latter depends on heavy numerical calculation,which contains uncertainty.By using connection of fiber bundles,this paper establishes an analytic formula for the latter,and the numerical work is simplified.It shows the mathematical structure of molecule is fiber bundle. 展开更多
关键词 molecular dynamics electronic state fiber bundle connection
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