Classical survival analysis assumes all subjects will experience the event of interest, but in some cases, a portion of the population may never encounter the event. These survival methods further assume independent s...Classical survival analysis assumes all subjects will experience the event of interest, but in some cases, a portion of the population may never encounter the event. These survival methods further assume independent survival times, which is not valid for honey bees, which live in nests. The study introduces a semi-parametric marginal proportional hazards mixture cure (PHMC) model with exchangeable correlation structure, using generalized estimating equations for survival data analysis. The model was tested on clustered right-censored bees survival data with a cured fraction, where two bee species were subjected to different entomopathogens to test the effect of the entomopathogens on the survival of the bee species. The Expectation-Solution algorithm is used to estimate the parameters. The study notes a weak positive association between cure statuses (ρ1=0.0007) and survival times for uncured bees (ρ2=0.0890), emphasizing their importance. The odds of being uncured for A. mellifera is higher than the odds for species M. ferruginea. The bee species, A. mellifera are more susceptible to entomopathogens icipe 7, icipe 20, and icipe 69. The Cox-Snell residuals show that the proposed semiparametric PH model generally fits the data well as compared to model that assume independent correlation structure. Thus, the semi parametric marginal proportional hazards mixture cure is parsimonious model for correlated bees survival data.展开更多
针对现有基于聚类算法的滑坡敏感性评价模型存在难以设置参数等问题,采用CURE(Clustering using representative)聚类算法建立区域滑坡敏感性评价模型,并对延安宝塔区进行评价.实验结果表明,评价结果与实际一致,并且准确度比KPSO(K-mean...针对现有基于聚类算法的滑坡敏感性评价模型存在难以设置参数等问题,采用CURE(Clustering using representative)聚类算法建立区域滑坡敏感性评价模型,并对延安宝塔区进行评价.实验结果表明,评价结果与实际一致,并且准确度比KPSO(K-means+particle swam opimization)模型高出17.2%,证明该模型的有效性,可为防灾减灾提供理论支撑.展开更多
The measures of steam curing and early-strengthening agents to promote the precast components to reach the target strength quickly can bring different degrees of damage to the concrete.Based on this,the new nanomateri...The measures of steam curing and early-strengthening agents to promote the precast components to reach the target strength quickly can bring different degrees of damage to the concrete.Based on this,the new nanomaterial CSH-the hydration product of cement effectively solves these measures’disadvantages,such as excessive energy consumption,thermal stress damage,and the introduction of external ions.In this paper,the effect of CSH on the early strength of precast fly ash concrete components was investigated in terms of setting time,workability,and mechanical properties and analyzed at the microscopic level using hydration temperature,XRD,and SEM.The results showed that under the same workability,CSH could significantly reduce the amount of admixture,shorten the final setting time,almost not affect the initial setting time,and accelerate the hydration of cement.At the optimum dose of 5%,the mechanical properties of the specimens were improved by more than 98%within 12 h of hydration,resulting in an earlier release time of 12 h and no risk of strength inversion later.The results of this paper give theoretical support to the behavior of precast components under steam-free curing.展开更多
为了提高传统CURE(clustering using representatives)聚类算法的质量,引入信息熵对其进行改进。该算法使用K-means算法对样本数据集进行预聚类;采用基于信息熵的相似性度量,利用簇中元素提供的信息度量不同簇之间的相互关系,并描述数...为了提高传统CURE(clustering using representatives)聚类算法的质量,引入信息熵对其进行改进。该算法使用K-means算法对样本数据集进行预聚类;采用基于信息熵的相似性度量,利用簇中元素提供的信息度量不同簇之间的相互关系,并描述数据的分布;在高、低层聚类阶段,采取不同的选取策略,分别选取相应的代表点。在UCI和人造数据集上的实验结果表明,提出的算法在一定程度上提高了聚类的准确率,且在大型数据集上比传统CURE算法有着更高的聚类效率。展开更多
CURE(the Clopidogres in Unstable angina to prevent Recurrent Events)试验的主要目的是观察氯吡格雷合用阿司匹林的长、短期疗效,确定是否优于单独使用阿司匹林.该试验采用多中心(28个国家,482家医院)随机双盲方法,1998年12月开始...CURE(the Clopidogres in Unstable angina to prevent Recurrent Events)试验的主要目的是观察氯吡格雷合用阿司匹林的长、短期疗效,确定是否优于单独使用阿司匹林.该试验采用多中心(28个国家,482家医院)随机双盲方法,1998年12月开始入组病人,共收集了12562例ST段抬高＜1 mm,缺血发作24小时以内的急性冠脉综合征病人,其中32.0%的患者即往有心肌梗死病史,22.5%有糖尿病史,58.0%有高血压史,11.0%有即往冠状动脉移植术史.展开更多
文摘Classical survival analysis assumes all subjects will experience the event of interest, but in some cases, a portion of the population may never encounter the event. These survival methods further assume independent survival times, which is not valid for honey bees, which live in nests. The study introduces a semi-parametric marginal proportional hazards mixture cure (PHMC) model with exchangeable correlation structure, using generalized estimating equations for survival data analysis. The model was tested on clustered right-censored bees survival data with a cured fraction, where two bee species were subjected to different entomopathogens to test the effect of the entomopathogens on the survival of the bee species. The Expectation-Solution algorithm is used to estimate the parameters. The study notes a weak positive association between cure statuses (ρ1=0.0007) and survival times for uncured bees (ρ2=0.0890), emphasizing their importance. The odds of being uncured for A. mellifera is higher than the odds for species M. ferruginea. The bee species, A. mellifera are more susceptible to entomopathogens icipe 7, icipe 20, and icipe 69. The Cox-Snell residuals show that the proposed semiparametric PH model generally fits the data well as compared to model that assume independent correlation structure. Thus, the semi parametric marginal proportional hazards mixture cure is parsimonious model for correlated bees survival data.
文摘针对现有基于聚类算法的滑坡敏感性评价模型存在难以设置参数等问题,采用CURE(Clustering using representative)聚类算法建立区域滑坡敏感性评价模型,并对延安宝塔区进行评价.实验结果表明,评价结果与实际一致,并且准确度比KPSO(K-means+particle swam opimization)模型高出17.2%,证明该模型的有效性,可为防灾减灾提供理论支撑.
文摘The measures of steam curing and early-strengthening agents to promote the precast components to reach the target strength quickly can bring different degrees of damage to the concrete.Based on this,the new nanomaterial CSH-the hydration product of cement effectively solves these measures’disadvantages,such as excessive energy consumption,thermal stress damage,and the introduction of external ions.In this paper,the effect of CSH on the early strength of precast fly ash concrete components was investigated in terms of setting time,workability,and mechanical properties and analyzed at the microscopic level using hydration temperature,XRD,and SEM.The results showed that under the same workability,CSH could significantly reduce the amount of admixture,shorten the final setting time,almost not affect the initial setting time,and accelerate the hydration of cement.At the optimum dose of 5%,the mechanical properties of the specimens were improved by more than 98%within 12 h of hydration,resulting in an earlier release time of 12 h and no risk of strength inversion later.The results of this paper give theoretical support to the behavior of precast components under steam-free curing.
文摘为了提高传统CURE(clustering using representatives)聚类算法的质量,引入信息熵对其进行改进。该算法使用K-means算法对样本数据集进行预聚类;采用基于信息熵的相似性度量,利用簇中元素提供的信息度量不同簇之间的相互关系,并描述数据的分布;在高、低层聚类阶段,采取不同的选取策略,分别选取相应的代表点。在UCI和人造数据集上的实验结果表明,提出的算法在一定程度上提高了聚类的准确率,且在大型数据集上比传统CURE算法有着更高的聚类效率。
文摘CURE(the Clopidogres in Unstable angina to prevent Recurrent Events)试验的主要目的是观察氯吡格雷合用阿司匹林的长、短期疗效,确定是否优于单独使用阿司匹林.该试验采用多中心(28个国家,482家医院)随机双盲方法,1998年12月开始入组病人,共收集了12562例ST段抬高＜1 mm,缺血发作24小时以内的急性冠脉综合征病人,其中32.0%的患者即往有心肌梗死病史,22.5%有糖尿病史,58.0%有高血压史,11.0%有即往冠状动脉移植术史.
