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空间双重平衡抽样设计及其应用? 被引量:1
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作者 郝一炜 刘晓宇 金勇进 《调研世界》 CSSCI 2019年第3期26-31,共6页
文章针对抽样调查中目标变量具有空间相关性的问题,提出了一种考虑到总体单元空间信息的空间双重平衡抽样设计方案。其思路是在抽样设计阶段同时利用与总体目标变量高度相关的辅助信息和总体单元的空间位置信息,获取在空间中均匀覆盖的... 文章针对抽样调查中目标变量具有空间相关性的问题,提出了一种考虑到总体单元空间信息的空间双重平衡抽样设计方案。其思路是在抽样设计阶段同时利用与总体目标变量高度相关的辅助信息和总体单元的空间位置信息,获取在空间中均匀覆盖的平衡样本,提升样本代表性。通过对北京市医疗资源调查的案例研究发现,相比传统平衡抽样方法,空间双重平衡抽样下的HT估计量具有更小的相对误差,该种方法在政府调查和商业调查等领域有较为广阔的应用前景。 展开更多
关键词 空间双重平衡抽样 空间抽样 DBSS 分层随机抽样 立方体法抽样
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Multi-objective Optimization Based on Unsteady Analysis Considering the Efficiency and Radial Force of a Single-Channel Pump for Wastewater Treatment 被引量:1
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作者 Jin-Hyuk Kim Bo-Min Cho +1 位作者 Yotmg-Seok Choi Kyotmg-Yong Lee 《Journal of Mechanics Engineering and Automation》 2016年第5期234-245,共12页
A multidisciplinary optimization was conducted to simultaneously improve the efficiency and reduce the radial force of a single-channel pump for wastewater treatment. A hybrid multi-objective evolutionary algorithm wa... A multidisciplinary optimization was conducted to simultaneously improve the efficiency and reduce the radial force of a single-channel pump for wastewater treatment. A hybrid multi-objective evolutionary algorithm was coupled with a surrogate model to optimize the geometry of the single-channel pump volute. Steady and unsteady Reynolds-averaged Navier-Stokes equations with a shear stress transport turbulence model were discretized using finite volume approximations and were then solved on tetrahedral grids to analyze the flow in the single-channel pump. The three objective functions represented the total efficiency, the sweep area of the radial force during one revolution, and the distance of the mass center of sweep area from the origin while the two design variables were related to the cross-sectional area of the internal flow of the volute. Latin hypercube sampling was employed to generate twelve design points within the design space, and response surface approximation models were constructed as surrogate models for the objectives based on the values of the objective function at the given design points. A fast non-dominated sorting genetic algorithm for local search was coupled with the surrogate models to determine the global Pareto-optimal solutions. The trade-off between the objectives was determined and was described in terms of the Pareto-optimal solutions. The results of the multi-objective optimization showed that the optimum design simultaneously improved the efficiency and reduced the radial force relative to those of the reference design. 展开更多
关键词 Single-channel pump EFFICIENCY radial force sweep area unsteady analysis optimization.
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