Reduced order models（ROMs） based on the snapshots on the CFD high-fidelity simulations have been paid great attention recently due to their capability of capturing the features of the complex geometries and flow con...Reduced order models（ROMs） based on the snapshots on the CFD high-fidelity simulations have been paid great attention recently due to their capability of capturing the features of the complex geometries and flow configurations. To improve the efficiency and precision of the ROMs, it is indispensable to add extra sampling points to the initial snapshots, since the number of sampling points to achieve an adequately accurate ROM is generally unknown in prior, but a large number of initial sampling points reduces the parsimony of the ROMs. A fuzzy-clustering-based adding-point strategy is proposed and the fuzzy clustering acts an indicator of the region in which the precision of ROMs is relatively low. The proposed method is applied to construct the ROMs for the benchmark mathematical examples and a numerical example of hypersonic aerothermodynamics prediction for a typical control surface. The proposed method can achieve a 34.5% improvement on the efficiency than the estimated mean squared error prediction algorithm and shows same-level prediction accuracy.展开更多
China, as a whole, is about to meet the Millennium Development Goals for reducing the maternal mortality ratio (MMR) and infant mortality rate (IMR), but the disparities between rural area and urban area still exists....China, as a whole, is about to meet the Millennium Development Goals for reducing the maternal mortality ratio (MMR) and infant mortality rate (IMR), but the disparities between rural area and urban area still exists. This study estimated the potential effectiveness of expanding coverage with high impact interventions using the Lives Saved Tool (LiST). It was found that gestational hypertension, antepartum and postpartum hemorrhage, preterm birth, neonatal asphyxia, and neonatal childhood pneumonia and diarrhea are still the major killers of mothers and children in rural area in China. It was estimated that 30% of deaths among 0-59 month old children and 25% of maternal deaths in 2008 could be prevented in 2015 if primary health care intervention coverage expanded to a feasible level. The LiST death cause framework, compared to data from the Maternal and Child Mortality Surveillance System, represents 60%-80% of neonatal deaths, 40%-50% of deaths in 1-59 month old children and 40%-60% of maternal deaths in rural areas of western China.展开更多
针对标准灰狼算法存在的收敛速度慢和容易陷入局部最优的问题,提出一种改进的灰狼优化算法(dynamic approach grey wolf optimization,DAGWO)。该算法采用新的个体位置移动策略,增加狼群攻击的多样性和随机性,提高了收敛速度;同时,引入...针对标准灰狼算法存在的收敛速度慢和容易陷入局部最优的问题,提出一种改进的灰狼优化算法(dynamic approach grey wolf optimization,DAGWO)。该算法采用新的个体位置移动策略,增加狼群攻击的多样性和随机性,提高了收敛速度;同时,引入基于停滞检测的随机初始化策略增加种群多样性,提高了全局搜索能力。通过12个基准测试函数的仿真实验,表明DAGWO算法的收敛速度和求解精度均明显优于其他算法。此外,将DAGWO算法应用于减速器设计问题,证明了其在工程优化问题上的可行性和有效性。展开更多
基金Supported by National Natural Science Foundation of China(Grant No.11372036)
文摘Reduced order models（ROMs） based on the snapshots on the CFD high-fidelity simulations have been paid great attention recently due to their capability of capturing the features of the complex geometries and flow configurations. To improve the efficiency and precision of the ROMs, it is indispensable to add extra sampling points to the initial snapshots, since the number of sampling points to achieve an adequately accurate ROM is generally unknown in prior, but a large number of initial sampling points reduces the parsimony of the ROMs. A fuzzy-clustering-based adding-point strategy is proposed and the fuzzy clustering acts an indicator of the region in which the precision of ROMs is relatively low. The proposed method is applied to construct the ROMs for the benchmark mathematical examples and a numerical example of hypersonic aerothermodynamics prediction for a typical control surface. The proposed method can achieve a 34.5% improvement on the efficiency than the estimated mean squared error prediction algorithm and shows same-level prediction accuracy.
基金supported jointly by WHO(CHN-12-MCN-005007)UNICEF(YH702H&N)Chinese Post-doctoral Foundation(2012M510295)
文摘China, as a whole, is about to meet the Millennium Development Goals for reducing the maternal mortality ratio (MMR) and infant mortality rate (IMR), but the disparities between rural area and urban area still exists. This study estimated the potential effectiveness of expanding coverage with high impact interventions using the Lives Saved Tool (LiST). It was found that gestational hypertension, antepartum and postpartum hemorrhage, preterm birth, neonatal asphyxia, and neonatal childhood pneumonia and diarrhea are still the major killers of mothers and children in rural area in China. It was estimated that 30% of deaths among 0-59 month old children and 25% of maternal deaths in 2008 could be prevented in 2015 if primary health care intervention coverage expanded to a feasible level. The LiST death cause framework, compared to data from the Maternal and Child Mortality Surveillance System, represents 60%-80% of neonatal deaths, 40%-50% of deaths in 1-59 month old children and 40%-60% of maternal deaths in rural areas of western China.
文摘针对标准灰狼算法存在的收敛速度慢和容易陷入局部最优的问题,提出一种改进的灰狼优化算法(dynamic approach grey wolf optimization,DAGWO)。该算法采用新的个体位置移动策略,增加狼群攻击的多样性和随机性,提高了收敛速度;同时,引入基于停滞检测的随机初始化策略增加种群多样性,提高了全局搜索能力。通过12个基准测试函数的仿真实验,表明DAGWO算法的收敛速度和求解精度均明显优于其他算法。此外,将DAGWO算法应用于减速器设计问题,证明了其在工程优化问题上的可行性和有效性。
