On the basis of Space-Wise Least Square method, three numerical methods including Cholesky de- composition, pre-conditioned conjugate gradient and Open Multi-Processing parallel algorithm are applied into the determin...On the basis of Space-Wise Least Square method, three numerical methods including Cholesky de- composition, pre-conditioned conjugate gradient and Open Multi-Processing parallel algorithm are applied into the determination of gravity field with satellite gravity gradiometry data. The results show that, Cholesky de- composition method has been unable to meet the requirements of computation efficiency when the computer hardware is limited. Pre-conditioned conjugate gradient method can improve the computation efficiency of huge matrix inversion, but it also brings a certain loss of precision. The application of Open Multi-Processing parallel algorithm could achieve a good compromise between accuracy and computation efficiency.展开更多
随着碳捕集、利用与封存(carbon capture,utilization and storage,CCUS)技术的快速发展,CO_(2)管道运输规模不断扩大,其管道泄漏风险的研究也备受关注。为了保障CO_(2)管道的安全运行和管理,为全球CCUS项目的安全实施提供更有力的支持...随着碳捕集、利用与封存(carbon capture,utilization and storage,CCUS)技术的快速发展,CO_(2)管道运输规模不断扩大,其管道泄漏风险的研究也备受关注。为了保障CO_(2)管道的安全运行和管理,为全球CCUS项目的安全实施提供更有力的支持,本文系统梳理了CO_(2)的管道泄漏危害、暴露浓度规定、管道失效概率、泄漏扩散浓度及距离和管道泄漏风险评估方法等方面的研究现状。研究现状表明,与CO_(2)管道泄漏引起的低温冻伤、噪声污染和杂质危害相关的研究缺乏;管道泄漏导致的CO_(2)泄漏扩散,其浓度的安全阈值规定不统一;在计算CO_(2)管道失效概率时,大部分采用天然气管道失效概率,且未根据管道实际情况进行失效概率修正;目前对工业规模CO_(2)管道的实验研究不足,且很难整合分析不同实验环境下CO_(2)管道泄漏造成的后果;CO_(2)泄漏扩散浓度的研究主要是基于商业软件模拟,可以用于浓度风险后果分析,但软件的适用性和准确性有待提高;对基于理论模型分析的CO_(2)泄漏扩散浓度模型研究不足;目前CO_(2)管道泄漏的风险评估主要采用的是定量风险评价(quantitative risk assessment,QRA)方法,风险评估方法比较单一;机器学习的引入可以为CO_(2)管道泄漏风险评估带来新的活力和更高的准确性。展开更多
GNSS的快速发展使得GNSS终端能够同时观测多达几十颗卫星.小型移动终端的计算资源无法满足对所有观测卫星进行定位解算的性能要求.针对该问题,提出了一种多策略融合的灰狼优化(multi-strategy grey wolf optimization,MSGWO)算法的快速...GNSS的快速发展使得GNSS终端能够同时观测多达几十颗卫星.小型移动终端的计算资源无法满足对所有观测卫星进行定位解算的性能要求.针对该问题,提出了一种多策略融合的灰狼优化(multi-strategy grey wolf optimization,MSGWO)算法的快速选星方法.MSGWO算法在灰狼优化(grey wolf optimizer,GWO)算法的基础上,融入变邻域搜索(variable neighborhood search,VNS)的交叉策略以及遗传算法(genetic algorithm,GA)的变异机制,以缓解GWO算法中易陷入局部最优解以及种群多样性少的问题.通过实测数据对MSGWO算法进行了验证与对比分析.结果表明,在多系统环境下,MSGWO算法的计算效率相较于遍历法提升92.38%.该算法适用于处理多星座系统中复杂的选星数目问题.展开更多
基金supproted by the National Natural Science Foundation of China(40874012,40904003,40974016,41004007)
文摘On the basis of Space-Wise Least Square method, three numerical methods including Cholesky de- composition, pre-conditioned conjugate gradient and Open Multi-Processing parallel algorithm are applied into the determination of gravity field with satellite gravity gradiometry data. The results show that, Cholesky de- composition method has been unable to meet the requirements of computation efficiency when the computer hardware is limited. Pre-conditioned conjugate gradient method can improve the computation efficiency of huge matrix inversion, but it also brings a certain loss of precision. The application of Open Multi-Processing parallel algorithm could achieve a good compromise between accuracy and computation efficiency.
文摘GNSS的快速发展使得GNSS终端能够同时观测多达几十颗卫星.小型移动终端的计算资源无法满足对所有观测卫星进行定位解算的性能要求.针对该问题,提出了一种多策略融合的灰狼优化(multi-strategy grey wolf optimization,MSGWO)算法的快速选星方法.MSGWO算法在灰狼优化(grey wolf optimizer,GWO)算法的基础上,融入变邻域搜索(variable neighborhood search,VNS)的交叉策略以及遗传算法(genetic algorithm,GA)的变异机制,以缓解GWO算法中易陷入局部最优解以及种群多样性少的问题.通过实测数据对MSGWO算法进行了验证与对比分析.结果表明,在多系统环境下,MSGWO算法的计算效率相较于遍历法提升92.38%.该算法适用于处理多星座系统中复杂的选星数目问题.
