In this paper, it is discussed that two tests for varying dispersion of binomial data in the framework of nonlinear logistic models with random effects, which are widely used in analyzing longitudinal binomial data. O...In this paper, it is discussed that two tests for varying dispersion of binomial data in the framework of nonlinear logistic models with random effects, which are widely used in analyzing longitudinal binomial data. One is the individual test and power calculation for varying dispersion through testing the randomness of cluster effects, which is extensions of Dean(1992) and Commenges et al (1994). The second test is the composite test for varying dispersion through simultaneously testing the randomness of cluster effects and the equality of random-effect means. The score test statistics are constructed and expressed in simple, easy to use, matrix formulas. The authors illustrate their test methods using the insecticide data (Giltinan, Capizzi & Malani (1988)).展开更多
Mixed models provide a wide range of applications including hierarchical modeling and longitudinal studies. The tests of variance component in mixed models have long been a methodological challenge because of its boun...Mixed models provide a wide range of applications including hierarchical modeling and longitudinal studies. The tests of variance component in mixed models have long been a methodological challenge because of its boundary conditions. It is well documented in literature that the traditional first-order methods: likelihood ratio statistic, Wald statistic and score statistic, provide an excessively conservative approximation to the null distribution. However, the magnitude of the conservativeness has not been thoroughly explored. In this paper, we propose a likelihood-based third-order method to the mixed models for testing the null hypothesis of zero and non-zero variance component. The proposed method dramatically improved the accuracy of the tests. Extensive simulations were carried out to demonstrate the accuracy of the proposed method in comparison with the standard first-order methods. The results show the conservativeness of the first order methods and the accuracy of the proposed method in approximating the p-values and confidence intervals even when the sample size is small.展开更多
测试数据自动生成方法是软件测试领域研究的热点。基于遗传算法的启发式搜索算法是一种路径覆盖生成测试数据的方法。文中提出了一种基于自适应随机测试(Adaptive Random Testing,ART)算法更新种群的方法,将ART融入遗传算法,优化选择操...测试数据自动生成方法是软件测试领域研究的热点。基于遗传算法的启发式搜索算法是一种路径覆盖生成测试数据的方法。文中提出了一种基于自适应随机测试(Adaptive Random Testing,ART)算法更新种群的方法,将ART融入遗传算法,优化选择操作,动态更新种群,从而增加种群进化过程中的个体多样性,提高了收敛速度,有效地减少了陷入局部最优。实验结果显示,与传统遗传算法生成测试数据的方法相比,改进的算法明显提高了路径覆盖率,减少了种群平均进化代数。展开更多
基金The project supported by NNSFC (19631040), NSSFC (04BTJ002) and the grant for post-doctor fellows in SELF.
文摘In this paper, it is discussed that two tests for varying dispersion of binomial data in the framework of nonlinear logistic models with random effects, which are widely used in analyzing longitudinal binomial data. One is the individual test and power calculation for varying dispersion through testing the randomness of cluster effects, which is extensions of Dean(1992) and Commenges et al (1994). The second test is the composite test for varying dispersion through simultaneously testing the randomness of cluster effects and the equality of random-effect means. The score test statistics are constructed and expressed in simple, easy to use, matrix formulas. The authors illustrate their test methods using the insecticide data (Giltinan, Capizzi & Malani (1988)).
文摘Mixed models provide a wide range of applications including hierarchical modeling and longitudinal studies. The tests of variance component in mixed models have long been a methodological challenge because of its boundary conditions. It is well documented in literature that the traditional first-order methods: likelihood ratio statistic, Wald statistic and score statistic, provide an excessively conservative approximation to the null distribution. However, the magnitude of the conservativeness has not been thoroughly explored. In this paper, we propose a likelihood-based third-order method to the mixed models for testing the null hypothesis of zero and non-zero variance component. The proposed method dramatically improved the accuracy of the tests. Extensive simulations were carried out to demonstrate the accuracy of the proposed method in comparison with the standard first-order methods. The results show the conservativeness of the first order methods and the accuracy of the proposed method in approximating the p-values and confidence intervals even when the sample size is small.
文摘测试数据自动生成方法是软件测试领域研究的热点。基于遗传算法的启发式搜索算法是一种路径覆盖生成测试数据的方法。文中提出了一种基于自适应随机测试(Adaptive Random Testing,ART)算法更新种群的方法,将ART融入遗传算法,优化选择操作,动态更新种群,从而增加种群进化过程中的个体多样性,提高了收敛速度,有效地减少了陷入局部最优。实验结果显示,与传统遗传算法生成测试数据的方法相比,改进的算法明显提高了路径覆盖率,减少了种群平均进化代数。
