This paper presents a neighborhood optimal trajectory online correction algorithm considering terminal time variation,and investigates its application range.Firstly,the motion model of midcourse guidance is establishe...This paper presents a neighborhood optimal trajectory online correction algorithm considering terminal time variation,and investigates its application range.Firstly,the motion model of midcourse guidance is established,and the online trajectory correction-regenerating strategy is introduced.Secondly,based on the neighborhood optimal control theory,a neighborhood optimal trajectory online correction algorithm considering the terminal time variation is proposed by adding the consideration of terminal time variation to the traditional neighborhood optimal trajectory correction method.Thirdly,the Monte Carlo simulation method is used to analyze the application range of the algorithm,which provides a basis for the division of application domain of the online correction algorithm and the online regeneration algorithm of midcourse guidance trajectory.Finally,the simulation results show that the algorithm has high real-time performance,and the online correction trajectory can meet the requirements of terminal constraint change.The application range of the algorithm is obtained through Monte Carlo simulation.展开更多
Based on the characteristics of large flow rate , low head , short annual operation time , and high reliability of the city flood-control pumping stations , a new-type shaft tubular pumping system featuring a shaft su...Based on the characteristics of large flow rate , low head , short annual operation time , and high reliability of the city flood-control pumping stations , a new-type shaft tubular pumping system featuring a shaft suction box and a siphon-type discharge passage with a vacuum breaker as the cutoff device was developed , which possesses such advantages as simple structure , reliable cutoff , and high energy performance.Taking some pumping stations as the case studies , in the light of the specified operation conditions , the hydraulic optimal design of the shaft-type tubular pumping system was determined and the optimized shape of the system was recommended.The performance prediction based on the computational fluid dynamics methodology was determined and the model test verification was conducted.The results show that the predicted data agree with the experimental head and efficiency so that both methods can be used to determine the performance of a real pumping station.Finally , the in-situ measurements of a pumping station during the commissioning period further verified that the shaft-type tubular pumping station with a siphon discharge passage is of higher efficiency , more reliable and stable.展开更多
A spectral match optimization based on grey incidence matrix was put forward to evaluate camouflage painting design.A synthetic degree of incidence (SDI) was defined to comprehensively reflect the spectrum similarity ...A spectral match optimization based on grey incidence matrix was put forward to evaluate camouflage painting design.A synthetic degree of incidence (SDI) was defined to comprehensively reflect the spectrum similarity based on theory of grey incidence analysis.A grey optimization model for camouflage painting sheme was constructed on the basis of SDI and grey incidence matrix.Its weight values were determined according to area percentages of all components in the camouflage scene,and a quantitative ordering for various schemes could be obtained according to the evaluation coefficients.Experiment results show that the method mentioned in this paper can provide a quantitative basis for the camouflage decision-making,and it can also be used in other camouflage scheme selection.展开更多
冬油菜越冬期与蕾薹期遭遇低温冻害是影响油菜产量的主要不利因素,增施钾肥是提高冬油菜抗逆性、减少油菜遭遇低温冻害所带来产量损失的有效措施。为明确不同钾肥用量对冻害后油菜产量损失程度的影响,本研究利用2022/2023和2023/2024年...冬油菜越冬期与蕾薹期遭遇低温冻害是影响油菜产量的主要不利因素,增施钾肥是提高冬油菜抗逆性、减少油菜遭遇低温冻害所带来产量损失的有效措施。为明确不同钾肥用量对冻害后油菜产量损失程度的影响,本研究利用2022/2023和2023/2024年在湖北省两地开展钾肥定位田间试验,对比了2023/2024年极端低温天气下钾肥用量(0、60、120、180、240 kg hm^(-2))对冻害后油菜产量及产量构成因子、地上部钾养分含量及分配、钾养分利用效率的影响,明确了低温冻害下油菜适宜的钾肥用量。结果表明,与2022/2023年度相比,2023/2024年的极端低温天气造成武汉和武穴试验点相同处理下的油菜分别减产13.4%~24.1%和35.7%~51.7%,地上部总生物量的降幅分别为32.3%~42.5%和23.9%~38.9%,产量降低分别主要表现在单株角果数(35.5%~56.0%)和千粒重(28.1%~31.6%)的降低。施钾缓解了冻害后油菜产量的降低程度,且在钾肥用量为180 kg hm^(-2)时油菜的减产程度最低。冻害后油菜籽粒钾含量及分配比例增加,地上部钾积累量显著降低,但钾素吸收利用率和钾肥偏生产力降低,施钾提高了油菜籽钾含量的增加幅度,减缓了地上部钾吸收量的降低,促进了非籽粒部分钾养分向籽粒的转移。线性加平台模型的拟合表明,冻害后武汉和武穴试验点的适宜钾肥用量分别为163.1 kg hm^(-2)和147.9 kg hm^(-2),相比2022/2023年适宜施钾量平均增加35.2 kg hm^(-2)。综上所述,在遇到低温冻害天气时,适当追施钾肥有助于改善油菜生长,缓解由于低温冻害对油菜造成的产量损失。展开更多
随着高性能计算体系结构的发展,软件与硬件都具有多层的并行结构。当不同纵向层级与横向分组的计算任务被划分到不同节点的不同处理器时,存在非常多的分配方式。这些分配方式一般在运行时由用户输入的多个并行参数来确定,并对计算效率...随着高性能计算体系结构的发展,软件与硬件都具有多层的并行结构。当不同纵向层级与横向分组的计算任务被划分到不同节点的不同处理器时,存在非常多的分配方式。这些分配方式一般在运行时由用户输入的多个并行参数来确定,并对计算效率影响很大。随着计算规模与复杂度的提升,多个并行参数的可配置空间越来越大,用户越来越难以确定最佳的并行参数值。这类运行时优化问题在科学计算应用中较为普遍,但相关的研究与解决方法比较少见。以VASP(Vienna Ab initio Simulation Package)应用为例,首先分析了该应用的多层并行结构,展示了不同并行参数配置引发的巨大运行速度差异。然后提出了一个基于约化并行效率指标的全自动运行优化方法,其不仅可以帮助用户简单快捷地确定最佳应用并行参数,而且可以帮助用户确定最佳的计算资源使用量,使应用可以高效率地扩展到大规模的并行计算中。最后将该优化方法与计算集群作业调度系统相融合应用于用户提交的真实VASP计算作业。统计结果表明,该方法显著提升了作业运行速度与超算资源的使用效率,具有很好的工程应用前景。展开更多
基金supported by the National Natural Science Foundation of China(61873278,62173339)。
文摘This paper presents a neighborhood optimal trajectory online correction algorithm considering terminal time variation,and investigates its application range.Firstly,the motion model of midcourse guidance is established,and the online trajectory correction-regenerating strategy is introduced.Secondly,based on the neighborhood optimal control theory,a neighborhood optimal trajectory online correction algorithm considering the terminal time variation is proposed by adding the consideration of terminal time variation to the traditional neighborhood optimal trajectory correction method.Thirdly,the Monte Carlo simulation method is used to analyze the application range of the algorithm,which provides a basis for the division of application domain of the online correction algorithm and the online regeneration algorithm of midcourse guidance trajectory.Finally,the simulation results show that the algorithm has high real-time performance,and the online correction trajectory can meet the requirements of terminal constraint change.The application range of the algorithm is obtained through Monte Carlo simulation.
基金support by the 11th Five Year Key Project of China’s National Scientific Supporting Plan(Grant No.2006BAB04A03)the Hydraulic Engineering Project from the Water Resources Department of Jiangsu Province(Grant No.2010023)
文摘Based on the characteristics of large flow rate , low head , short annual operation time , and high reliability of the city flood-control pumping stations , a new-type shaft tubular pumping system featuring a shaft suction box and a siphon-type discharge passage with a vacuum breaker as the cutoff device was developed , which possesses such advantages as simple structure , reliable cutoff , and high energy performance.Taking some pumping stations as the case studies , in the light of the specified operation conditions , the hydraulic optimal design of the shaft-type tubular pumping system was determined and the optimized shape of the system was recommended.The performance prediction based on the computational fluid dynamics methodology was determined and the model test verification was conducted.The results show that the predicted data agree with the experimental head and efficiency so that both methods can be used to determine the performance of a real pumping station.Finally , the in-situ measurements of a pumping station during the commissioning period further verified that the shaft-type tubular pumping station with a siphon discharge passage is of higher efficiency , more reliable and stable.
文摘A spectral match optimization based on grey incidence matrix was put forward to evaluate camouflage painting design.A synthetic degree of incidence (SDI) was defined to comprehensively reflect the spectrum similarity based on theory of grey incidence analysis.A grey optimization model for camouflage painting sheme was constructed on the basis of SDI and grey incidence matrix.Its weight values were determined according to area percentages of all components in the camouflage scene,and a quantitative ordering for various schemes could be obtained according to the evaluation coefficients.Experiment results show that the method mentioned in this paper can provide a quantitative basis for the camouflage decision-making,and it can also be used in other camouflage scheme selection.
文摘冬油菜越冬期与蕾薹期遭遇低温冻害是影响油菜产量的主要不利因素,增施钾肥是提高冬油菜抗逆性、减少油菜遭遇低温冻害所带来产量损失的有效措施。为明确不同钾肥用量对冻害后油菜产量损失程度的影响,本研究利用2022/2023和2023/2024年在湖北省两地开展钾肥定位田间试验,对比了2023/2024年极端低温天气下钾肥用量(0、60、120、180、240 kg hm^(-2))对冻害后油菜产量及产量构成因子、地上部钾养分含量及分配、钾养分利用效率的影响,明确了低温冻害下油菜适宜的钾肥用量。结果表明,与2022/2023年度相比,2023/2024年的极端低温天气造成武汉和武穴试验点相同处理下的油菜分别减产13.4%~24.1%和35.7%~51.7%,地上部总生物量的降幅分别为32.3%~42.5%和23.9%~38.9%,产量降低分别主要表现在单株角果数(35.5%~56.0%)和千粒重(28.1%~31.6%)的降低。施钾缓解了冻害后油菜产量的降低程度,且在钾肥用量为180 kg hm^(-2)时油菜的减产程度最低。冻害后油菜籽粒钾含量及分配比例增加,地上部钾积累量显著降低,但钾素吸收利用率和钾肥偏生产力降低,施钾提高了油菜籽钾含量的增加幅度,减缓了地上部钾吸收量的降低,促进了非籽粒部分钾养分向籽粒的转移。线性加平台模型的拟合表明,冻害后武汉和武穴试验点的适宜钾肥用量分别为163.1 kg hm^(-2)和147.9 kg hm^(-2),相比2022/2023年适宜施钾量平均增加35.2 kg hm^(-2)。综上所述,在遇到低温冻害天气时,适当追施钾肥有助于改善油菜生长,缓解由于低温冻害对油菜造成的产量损失。
文摘随着高性能计算体系结构的发展,软件与硬件都具有多层的并行结构。当不同纵向层级与横向分组的计算任务被划分到不同节点的不同处理器时,存在非常多的分配方式。这些分配方式一般在运行时由用户输入的多个并行参数来确定,并对计算效率影响很大。随着计算规模与复杂度的提升,多个并行参数的可配置空间越来越大,用户越来越难以确定最佳的并行参数值。这类运行时优化问题在科学计算应用中较为普遍,但相关的研究与解决方法比较少见。以VASP(Vienna Ab initio Simulation Package)应用为例,首先分析了该应用的多层并行结构,展示了不同并行参数配置引发的巨大运行速度差异。然后提出了一个基于约化并行效率指标的全自动运行优化方法,其不仅可以帮助用户简单快捷地确定最佳应用并行参数,而且可以帮助用户确定最佳的计算资源使用量,使应用可以高效率地扩展到大规模的并行计算中。最后将该优化方法与计算集群作业调度系统相融合应用于用户提交的真实VASP计算作业。统计结果表明,该方法显著提升了作业运行速度与超算资源的使用效率,具有很好的工程应用前景。
