Accurate estimation of disease prevalence is crucial for effective public health intervention and resource allocation.Generating data by individual testing methods is often impractical and expensive for large populati...Accurate estimation of disease prevalence is crucial for effective public health intervention and resource allocation.Generating data by individual testing methods is often impractical and expensive for large populations,particularly when disease prevalence is low.Pool testing involves combining samples from multiple individuals into a pool and performing a single test,and offers a costeffective and efficient alternative.In pool testing strategy with retesting,if a pool tests negative,it is classified as non-defective,whereas if it is positive,then a retest is needed.The retesting strategy mitigates the effects of initial test errors,thereby enhancing the accuracy of the estimation of the prevalence rate.Evidence in the literature indicates that the traditional Wald method has been used to construct approximate confidence intervals for the prevalence rate.However,this interval estimation method is based on the normality ap-proximation and hence may not be accurate when the true prevalence rate is close to zero.In this paper,we propose a Bayesian interval estimation ap-proach which is not affected by extreme values of the prevalence rate and al-lows for incorporating prior information about the prevalence rate.We as-sumed that the prior distribution for the unknown prevalence rate p is a Beta distribution with parameters α_(0) and β_(0) and based on pool testing outcomes for the n pools each of size k,100(1-α)% credible intervals were constructed from the resulting posterior distribution.Simulation studies were carried out to compare the efficiencies of the Bayesian and Wald interval estimation methods for various values of p.展开更多
针对爆炸实验水池强度设计问题,利用非线性动力学程序LS-DYNA对10 kg TNT爆炸后的水中冲击波传播规律及爆炸水池结构动态响应情况进行了数值模拟,对空气桶和气泡帷幕削弱水中冲击波的能力进行了定量计算,结果表明:空气桶对冲击波峰值压...针对爆炸实验水池强度设计问题,利用非线性动力学程序LS-DYNA对10 kg TNT爆炸后的水中冲击波传播规律及爆炸水池结构动态响应情况进行了数值模拟,对空气桶和气泡帷幕削弱水中冲击波的能力进行了定量计算,结果表明:空气桶对冲击波峰值压力削弱作用接近50%,对比冲量削弱作用达到16.2%;气泡帷幕对壁面反射冲击波的削弱作用高达86.2%,对比冲量削弱作用达到75.6%。在此基础上进一步分析了冲击载荷作用以及结构响应机理,指出了内衬钢板和混凝土围堰的危险区域,对爆炸能量在各物质间的分配和传递规律进行了初步探索,为相关爆炸水池的工程设计提供参考。展开更多
文摘Accurate estimation of disease prevalence is crucial for effective public health intervention and resource allocation.Generating data by individual testing methods is often impractical and expensive for large populations,particularly when disease prevalence is low.Pool testing involves combining samples from multiple individuals into a pool and performing a single test,and offers a costeffective and efficient alternative.In pool testing strategy with retesting,if a pool tests negative,it is classified as non-defective,whereas if it is positive,then a retest is needed.The retesting strategy mitigates the effects of initial test errors,thereby enhancing the accuracy of the estimation of the prevalence rate.Evidence in the literature indicates that the traditional Wald method has been used to construct approximate confidence intervals for the prevalence rate.However,this interval estimation method is based on the normality ap-proximation and hence may not be accurate when the true prevalence rate is close to zero.In this paper,we propose a Bayesian interval estimation ap-proach which is not affected by extreme values of the prevalence rate and al-lows for incorporating prior information about the prevalence rate.We as-sumed that the prior distribution for the unknown prevalence rate p is a Beta distribution with parameters α_(0) and β_(0) and based on pool testing outcomes for the n pools each of size k,100(1-α)% credible intervals were constructed from the resulting posterior distribution.Simulation studies were carried out to compare the efficiencies of the Bayesian and Wald interval estimation methods for various values of p.
文摘针对爆炸实验水池强度设计问题,利用非线性动力学程序LS-DYNA对10 kg TNT爆炸后的水中冲击波传播规律及爆炸水池结构动态响应情况进行了数值模拟,对空气桶和气泡帷幕削弱水中冲击波的能力进行了定量计算,结果表明:空气桶对冲击波峰值压力削弱作用接近50%,对比冲量削弱作用达到16.2%;气泡帷幕对壁面反射冲击波的削弱作用高达86.2%,对比冲量削弱作用达到75.6%。在此基础上进一步分析了冲击载荷作用以及结构响应机理,指出了内衬钢板和混凝土围堰的危险区域,对爆炸能量在各物质间的分配和传递规律进行了初步探索,为相关爆炸水池的工程设计提供参考。
