许多系统把数据访问请求当作是独立的事件。实际上,数据请求并非完全随机,而是由用户或程序的行为驱动的,不同的用户或程序存在不同的访问模式。LS(Last Successor)模型简单,但非常有效,然而它的预测结果严重依赖于用户或程序的访问顺...许多系统把数据访问请求当作是独立的事件。实际上,数据请求并非完全随机,而是由用户或程序的行为驱动的,不同的用户或程序存在不同的访问模式。LS(Last Successor)模型简单,但非常有效,然而它的预测结果严重依赖于用户或程序的访问顺序。提出了ULNS(User-based Last N Successors)文件预测模型,利用用户信息来提高预测精确度,并综合LS模型来改进算法的可适用度。实验结果表明,该预测模型具有较好的整体性能。展开更多
Background: Hyperthyroidism is a major cause of paroxysmal atrial fibrillation(AF). The purpose of this study was to evaluate the predictors of AF in the patients with clinical and subclinical hyperthyroidism. Methods...Background: Hyperthyroidism is a major cause of paroxysmal atrial fibrillation(AF). The purpose of this study was to evaluate the predictors of AF in the patients with clinical and subclinical hyperthyroidism. Methods and Results: The study population consisted of four groups: group I(57 euthyroid healthy persons), group II(33 patients with subclinical hyperthyroidism), group III(69 patients with overt hyperthyroidism) and group IV(31 patients with overt hyperthyroidism and documented paroxysmal AF). The maximum P wave duration(P maximum) in group IV(114±8 ms) was significantly higher than group I(102±7 ms, p< 0.001), group II(106±7 ms, p< 0,001)-and group III(108±9 ms, p< 0.005). The P wave dispersion(PWD) was measured as 46±9 ms in group IV and this was significantly higher than group I(29±8 ms, p< 0.001), group II(36±9 ms, p< 0.001) and grup III(38±8 ms, p=0.001). The P maximum and PWD were higher in the patients with subclinical hyperthyroidism compared to healthy individuals. Univariate regression analysis revealed that age, P maximum and PWD, multivariate analysis showed that P maximum and PWD were significant predictors of paroxysmal AF. A PWD value of 37.5 ms separated group IV from others with a sensitivity of 90%, specificity of 85%, and positive predictive accuracy of 77%. Conclusion: Simply measuring P maximum and PWD values, we could identify the patients with high risk for the development of AF and these simple ECG parameters may help in clinical judgement to determine the requirement for treatment in the patients with subclinical hyperthyroidism.展开更多
基金国家自然科学基金( the National Natural Science Foundation of China under Grant No.90412017)
文摘许多系统把数据访问请求当作是独立的事件。实际上,数据请求并非完全随机,而是由用户或程序的行为驱动的,不同的用户或程序存在不同的访问模式。LS(Last Successor)模型简单,但非常有效,然而它的预测结果严重依赖于用户或程序的访问顺序。提出了ULNS(User-based Last N Successors)文件预测模型,利用用户信息来提高预测精确度,并综合LS模型来改进算法的可适用度。实验结果表明,该预测模型具有较好的整体性能。
文摘Background: Hyperthyroidism is a major cause of paroxysmal atrial fibrillation(AF). The purpose of this study was to evaluate the predictors of AF in the patients with clinical and subclinical hyperthyroidism. Methods and Results: The study population consisted of four groups: group I(57 euthyroid healthy persons), group II(33 patients with subclinical hyperthyroidism), group III(69 patients with overt hyperthyroidism) and group IV(31 patients with overt hyperthyroidism and documented paroxysmal AF). The maximum P wave duration(P maximum) in group IV(114±8 ms) was significantly higher than group I(102±7 ms, p< 0.001), group II(106±7 ms, p< 0,001)-and group III(108±9 ms, p< 0.005). The P wave dispersion(PWD) was measured as 46±9 ms in group IV and this was significantly higher than group I(29±8 ms, p< 0.001), group II(36±9 ms, p< 0.001) and grup III(38±8 ms, p=0.001). The P maximum and PWD were higher in the patients with subclinical hyperthyroidism compared to healthy individuals. Univariate regression analysis revealed that age, P maximum and PWD, multivariate analysis showed that P maximum and PWD were significant predictors of paroxysmal AF. A PWD value of 37.5 ms separated group IV from others with a sensitivity of 90%, specificity of 85%, and positive predictive accuracy of 77%. Conclusion: Simply measuring P maximum and PWD values, we could identify the patients with high risk for the development of AF and these simple ECG parameters may help in clinical judgement to determine the requirement for treatment in the patients with subclinical hyperthyroidism.
