The concept of cointegration is widely used in applied non-stationary time series analysis to describe the co-movement of data measured over time. In this paper, we proposed a Bayesian model for cointegration test and...The concept of cointegration is widely used in applied non-stationary time series analysis to describe the co-movement of data measured over time. In this paper, we proposed a Bayesian model for cointegration test and analysis, based on the dynamic latent factor framework. Efficient computational algorithms are also developed based on Markov Chain Monte Carlo (MCMC). Performance and efficiency of the the model and approaches are assessed by simulated and real data analysis.展开更多
To solve the problem of the spatial correlation for adjacent areas in traditional spectral unmixing methods, we propose an area-correlated spectral unmixing method based on Bayesian nonnegative matrix factorization. I...To solve the problem of the spatial correlation for adjacent areas in traditional spectral unmixing methods, we propose an area-correlated spectral unmixing method based on Bayesian nonnegative matrix factorization. In the proposed me-thod, the spatial correlation property between two adjacent areas is expressed by a priori probability density function, and the endmembers extracted from one of the adjacent areas are used to estimate the priori probability density func-tions of the endmembers in the current area, which works as a type of constraint in the iterative spectral unmixing process. Experimental results demonstrate the effectivity and efficiency of the proposed method both for synthetic and real hyperspectral images, and it can provide a useful tool for spatial correlation and comparation analysis between ad-jacent or similar areas.展开更多
A Bayesian network (BN) model was developed to predict susceptibility to PWD(Pine Wilt Disease). The distribution of PWD was identified using QuickBird and unmanned aerial vehicle (UAV) images taken at different times...A Bayesian network (BN) model was developed to predict susceptibility to PWD(Pine Wilt Disease). The distribution of PWD was identified using QuickBird and unmanned aerial vehicle (UAV) images taken at different times. Seven factors that influence the distribution of PWD were extracted from the QuickBird images and were used as the independent variables. The results showed that the BN model predicted PWD with high accuracy. In a sensitivity analysis, elevation (EL), the normal differential vegetation index (NDVI), the distance to settlements (DS) and the distance to roads (DR) were strongly associated with PWD prevalence, and slope (SL) exhibited the weakest association with PWD prevalence. The study showed that BN is an effective tool for modeling PWD prevalence and quantifying the impact of various factors.展开更多
In the multistage reliability growth tests with instant and delayed fix modes, the failure data can be assumed to follow Weibull processes with different parameters at different stages. For the Weibull process within ...In the multistage reliability growth tests with instant and delayed fix modes, the failure data can be assumed to follow Weibull processes with different parameters at different stages. For the Weibull process within a stage, by the proper selection of prior distribution form and the parameters, a concise posterior distribution form is obtained, thus simplifying the Bayesian analysis. In the multistage tests, the improvement factor is used to convert the posterior of one stage to the prior of the subsequent stage. The conversion criterion is carefully analyzed to determine the distribution parameters of the subsequent stage＇s variable reasonably. Based on the mentioned results, a new synthetic Bayesian evaluation program and algorithm framework is put forward to evaluate the multistage reliability growth tests with instant and delayed fix modes. The example shows the effectiveness and flexibility of this method.展开更多
目的分析2010—2020年恩施州手足口病(hand,foot and mouth disease,HFMD)的流行特征,探讨社会经济与气象因素的影响,并评估疫情防控措施对HFMD的干预效果。方法运用ArcGIS 10.8对恩施州88个乡级行政单元的HFMD病例进行时空特征可视化;...目的分析2010—2020年恩施州手足口病(hand,foot and mouth disease,HFMD)的流行特征,探讨社会经济与气象因素的影响,并评估疫情防控措施对HFMD的干预效果。方法运用ArcGIS 10.8对恩施州88个乡级行政单元的HFMD病例进行时空特征可视化;采用贝叶斯时空模型解析社会经济与气象因素对疾病分布的影响;使用SEIR模型估算易感人群人数与比例;构建时间序列模型,预测2020年发病趋势并量化疫情防控措施效果。结果2010—2020年累计报告病例58954例,年均发病率为11.90/10万,死亡率为0.01/10万,≤5岁儿童占发病人数的93.20%;居民储蓄存款每增加1个标准差单位,发病率下降1.1%(P<0.05);医院床位数与发病率呈正相关;气温升高(β=0.182)和降水增多(β=0.229)增加发病风险;疫情防控措施使发病数每月减少415例(P=0.049),但防控放松后,2020年12月发病数较2019年同期增长266.6%,呈现补偿性流行特征。结论本研究揭示了恩施州HFMD的时空分布特征及社会经济气象驱动因素,量化了疫情防控措施效果,为山区传染病精准防控提供了多维度依据。展开更多
文摘The concept of cointegration is widely used in applied non-stationary time series analysis to describe the co-movement of data measured over time. In this paper, we proposed a Bayesian model for cointegration test and analysis, based on the dynamic latent factor framework. Efficient computational algorithms are also developed based on Markov Chain Monte Carlo (MCMC). Performance and efficiency of the the model and approaches are assessed by simulated and real data analysis.
文摘To solve the problem of the spatial correlation for adjacent areas in traditional spectral unmixing methods, we propose an area-correlated spectral unmixing method based on Bayesian nonnegative matrix factorization. In the proposed me-thod, the spatial correlation property between two adjacent areas is expressed by a priori probability density function, and the endmembers extracted from one of the adjacent areas are used to estimate the priori probability density func-tions of the endmembers in the current area, which works as a type of constraint in the iterative spectral unmixing process. Experimental results demonstrate the effectivity and efficiency of the proposed method both for synthetic and real hyperspectral images, and it can provide a useful tool for spatial correlation and comparation analysis between ad-jacent or similar areas.
文摘A Bayesian network (BN) model was developed to predict susceptibility to PWD(Pine Wilt Disease). The distribution of PWD was identified using QuickBird and unmanned aerial vehicle (UAV) images taken at different times. Seven factors that influence the distribution of PWD were extracted from the QuickBird images and were used as the independent variables. The results showed that the BN model predicted PWD with high accuracy. In a sensitivity analysis, elevation (EL), the normal differential vegetation index (NDVI), the distance to settlements (DS) and the distance to roads (DR) were strongly associated with PWD prevalence, and slope (SL) exhibited the weakest association with PWD prevalence. The study showed that BN is an effective tool for modeling PWD prevalence and quantifying the impact of various factors.
基金supported by Pre-research Foundation of General Armament Department of China(xxxxxxxxxxxx06KG0164)and the National Doctoral Foundation of China (2005999807).
文摘In the multistage reliability growth tests with instant and delayed fix modes, the failure data can be assumed to follow Weibull processes with different parameters at different stages. For the Weibull process within a stage, by the proper selection of prior distribution form and the parameters, a concise posterior distribution form is obtained, thus simplifying the Bayesian analysis. In the multistage tests, the improvement factor is used to convert the posterior of one stage to the prior of the subsequent stage. The conversion criterion is carefully analyzed to determine the distribution parameters of the subsequent stage＇s variable reasonably. Based on the mentioned results, a new synthetic Bayesian evaluation program and algorithm framework is put forward to evaluate the multistage reliability growth tests with instant and delayed fix modes. The example shows the effectiveness and flexibility of this method.
文摘目的分析2010—2020年恩施州手足口病(hand,foot and mouth disease,HFMD)的流行特征,探讨社会经济与气象因素的影响,并评估疫情防控措施对HFMD的干预效果。方法运用ArcGIS 10.8对恩施州88个乡级行政单元的HFMD病例进行时空特征可视化;采用贝叶斯时空模型解析社会经济与气象因素对疾病分布的影响;使用SEIR模型估算易感人群人数与比例;构建时间序列模型,预测2020年发病趋势并量化疫情防控措施效果。结果2010—2020年累计报告病例58954例,年均发病率为11.90/10万,死亡率为0.01/10万,≤5岁儿童占发病人数的93.20%;居民储蓄存款每增加1个标准差单位,发病率下降1.1%(P<0.05);医院床位数与发病率呈正相关;气温升高(β=0.182)和降水增多(β=0.229)增加发病风险;疫情防控措施使发病数每月减少415例(P=0.049),但防控放松后,2020年12月发病数较2019年同期增长266.6%,呈现补偿性流行特征。结论本研究揭示了恩施州HFMD的时空分布特征及社会经济气象驱动因素,量化了疫情防控措施效果,为山区传染病精准防控提供了多维度依据。
