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研究设计中样本量的确定 被引量:9
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作者 鲍贵 《外国语文》 北大核心 2014年第5期115-121,共7页
样本量的确定是研究设计的重要环节,因为它直接影响到统计效力和统计结论效度。鉴于外语教学研究者对确定合适样本量的重要性缺乏充分的认识,以方差分析为例介绍决定研究所需样本量的三个参数——第一类错误率、统计效力和效应量(或非... 样本量的确定是研究设计的重要环节,因为它直接影响到统计效力和统计结论效度。鉴于外语教学研究者对确定合适样本量的重要性缺乏充分的认识,以方差分析为例介绍决定研究所需样本量的三个参数——第一类错误率、统计效力和效应量(或非中心参数),同时探讨这些参数之间的关系及其对样本量的影响,并进一步讨论估计总体效应量的常用手段和计算研究所需样本量的常用方法。 展开更多
关键词 统计效力 样本量 效应量 第一类错误率 第二类错误率
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Construction of improved rigid blocks failure mechanism for ultimate bearing capacity calculation based on slip-line field theory 被引量:5
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作者 赵炼恒 杨峰 《Journal of Central South University》 SCIE EI CAS 2013年第4期1047-1057,共11页
Based on the slip-line field theory, a two-dimensional slip failure mechanism with mesh-like rigid block system was constructed to analyze the ultimate bearing capacity problems of rough foundation within the framewor... Based on the slip-line field theory, a two-dimensional slip failure mechanism with mesh-like rigid block system was constructed to analyze the ultimate bearing capacity problems of rough foundation within the framework of the upper bound limit analysis theorem. In the velocity discontinuities in transition area, the velocity changes in radial and tangent directions are allowed. The objective functions of the stability problems of geotechnical structures are obtained by equating the work rate of external force to internal dissipation along the velocity discontinuities, and then the objective functions are transformed as an upper-bound mathematic optimization model. The upper bound solutions for the objective functions are obtained by use of the nonlinear sequential quadratic programming and interior point method. From the numerical results and comparative analysis, it can be seen that the method presented in this work gives better calculation results than existing upper bound methods and can be used to establish the more accurate plastic collapse load for the ultimate bearing capacity of rough foundation. 展开更多
关键词 ultimate bearing capacity rough foundation slip-line field theory upper bound limit analysis theorem slip failure mechanism nonlinear programming method
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