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基于改进保守凸可分近似的高超声速飞行器轨迹规划方法
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作者 祝静娴 王剑颖 +1 位作者 罗云皓 王永海 《宇航学报》 EI CAS CSCD 北大核心 2024年第6期935-947,共13页
面向高超声速飞行器轨迹在线规划需求,提出一种改进的保守凸可分近似规划方法,以解决当前序列凸优化的振荡不收敛问题。首先,基于序列凸化、松弛变量、罚函数等方法将高超声速飞行器轨迹规划这一非凸原问题转化为凸的子问题。其次,针对... 面向高超声速飞行器轨迹在线规划需求,提出一种改进的保守凸可分近似规划方法,以解决当前序列凸优化的振荡不收敛问题。首先,基于序列凸化、松弛变量、罚函数等方法将高超声速飞行器轨迹规划这一非凸原问题转化为凸的子问题。其次,针对凸优化中的振荡不收敛问题,设计一种使迭代序列趋于聚点的信赖域更新策略,并验证该策略能有效避免迭代中后期进程缓慢的“振荡现象”。进一步地,结合改进的信赖域更新策略,提出基于改进保守凸可分近似的轨迹规划方法,并对算法进行等效性和收敛性分析,证明该算法能够收敛到原问题的一个驻点。最后,以复杂约束条件下的高超声速飞行器轨迹规划问题为例,对随机初始猜测值和随机终点两种工况进行仿真验证,并与序列二次规划方法的规划结果进行对比,结果表明本文算法在满足求解精度的要求下,具有较快的求解速度、以及较好的收敛性和鲁棒性。 展开更多
关键词 在线轨迹规划 序列凸优化 保守凸可分近似 信赖域
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地震偏移的最优可分近似算法实现 被引量:14
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作者 张致付 刘洪 +1 位作者 陈景波 李幼铭 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2005年第6期1422-1427,共6页
针对地震偏移算法中单程波算子的特征函数近似,采用最优可分表示法将该特征函数展开为空间变量(g)和水平波数(k)的可分表达式,以此可分近似表达式为基础,运用正反Fourier变换重新构造单程波算子.为了克服特征函数最优可分近似计算在奇... 针对地震偏移算法中单程波算子的特征函数近似,采用最优可分表示法将该特征函数展开为空间变量(g)和水平波数(k)的可分表达式,以此可分近似表达式为基础,运用正反Fourier变换重新构造单程波算子.为了克服特征函数最优可分近似计算在奇点及其领域产生的数值振荡,引入等价黏性技巧以增强算法的数值计算稳定性,并采用分频最优可分及对空间变量(g)线性插值的方法,不仅提高了计算精度,也节约计算机时.文中具体研究了单程波算子的脉冲响应和二维叠前深度偏移.结果表明,在不甚大步长情况下,本文构造的算子具有适应横向强变速的能力,运用Marmousi模型验证了本文方法适合复杂构造的成像. 展开更多
关键词 最优可分近似 单程波算子 特征函数 偏移
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EFFICIENT METHOD FOR MULTIDISCIPLINARY DESIGN OPTIMIZATION BY CONSIDERING UNCERTAINTY
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作者 贺谦 李元生 +2 位作者 敖良波 温志勋 岳珠峰 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2010年第3期213-218,共6页
A new reliability-based multidisciplinary design optimization (RBMDO) framework is proposed by combining the single-loop-based reliability analysis (SLBRA) method with multidisciplinary feasible (MDF) method. Th... A new reliability-based multidisciplinary design optimization (RBMDO) framework is proposed by combining the single-loop-based reliability analysis (SLBRA) method with multidisciplinary feasible (MDF) method. The Kriging approximate model with updating is introduced to reduce the computational cost of MDF caused by the complex structure. The computational efficiency is remarkably improved as the lack of iterative process during reliability analysis. Special attention is paid to a turbine blade design optimization by adopting the proposed method. Results show that the method is much more efficient than the commonly used double-loop based RBMDO method. It is feasible and efficient to apply the method to the engineering design. 展开更多
关键词 multidisciplinary design optimization multidisciplinary feasible method single loop method reliability analysis Kriging approximate model
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Accuracy analysis of the optimal separable approximation method of one-way wave migration
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作者 杜淑媛 陈景波 刘洪 《Applied Geophysics》 SCIE CSCD 2011年第4期328-336,371,372,共11页
An approximation for the one-way wave operator takes the form of separated space and wave-number variables and makes it possible to use the FFT, which results in a great improvement in the computational efficiency. Fr... An approximation for the one-way wave operator takes the form of separated space and wave-number variables and makes it possible to use the FFT, which results in a great improvement in the computational efficiency. From the function approximation perspective, the OSA method shares the same separable approximation format to the one-way wave operator as other separable approximation methods but it is the only global function approximation among these methods. This leads to a difference in the phase error curve, impulse response, and migration result from other separable approximation methods. The difference is that the OSA method has higher accuracy, and the sensitivity to the velocity variation declines with increasing order. 展开更多
关键词 one-way wave operator MIGRATION separable approximation optimal separable approximation
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Variable Separation Approach to Solve a (2+1)-Dimensional Integrable System
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作者 SHENShou-Feng PANZu-Liang ZHANGJun 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第4期497-498,共2页
In this letter, starting from a B?cklund transformation, a general solution of a (2+1)-dimensional integrable system is obtained by using the new variable separation approach.
关键词 variable separation approach (2+1)-dimensional integrable system localized coherent structure
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An approach for approximate solution of fractional-order smoking model with relapse class 被引量:1
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作者 Anwar Zeb Vedat Suat Erturk +2 位作者 Umar Khan Gul Zaman Shaher Momani 《International Journal of Biomathematics》 SCIE 2018年第6期31-57,共27页
In this paper, we develop a fractional-order smoking model by considering relapse class. First, we formulate the model and find the unique positive solution for the proposed model. Then we apply the Griinwald-Letnikov... In this paper, we develop a fractional-order smoking model by considering relapse class. First, we formulate the model and find the unique positive solution for the proposed model. Then we apply the Griinwald-Letnikov approximation in the place of maintaining a general quadrature formula approach to the Riemann-Liouville integral definition of the fractional derivative. Building on this foundation avoids the need for domain trans-formations, contour integration or involved theory to compute accurate approximate solutions of fractional-order giving up smoking model A comparative study between Griinwald-Letnikov method and Runge-Kutta method is presented in the case of integer-order derivative. Finally, we present the obtained results graphically. 展开更多
关键词 Mathematical model reproductive number next generation matrix method stability analysis Griinwald-Letnikov method numerical simulation.
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