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AN L^(∞) SECOND ORDER CARTESIAN METHOD FOR 3D ANISOTROPIC INTERFACE PROBLEMS

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Journal of Computational Mathematics 2022年第6期40卷 882-912页

作者： baiying dong Xiufeng Feng Zhilin Li School of Mathematics and Statistics NingXia UniversityYinchuan 750021China School of Mathematics and Computer Science NingXia Normal UniversityGuyuan 756000China Department of Mathematics North Carolina State UniversityRaleighNC 27695-8205USA

A second order accurate method in the infinity norm is proposed for general three dimensional anisotropic elliptic interface problems in which the solution and its derivatives,the coefficients,and source terms all can have finite jumps across one or several arbitrary smooth *** method is based on the 2D finite element-finite difference(FEFD)method but with substantial differences in method derivation,implementation,and convergence *** of challenges is to derive 3D interface relations since there is no invariance anymore under coordinate system transforms for the partial differential equations and the jump conditions.A finite element discretization whose coefficient matrix is a symmetric semi-positive definite is used away from the interface;and the maximum preserving finite difference discretization whose coefficient matrix part is an M-matrix is constructed at irregular elements where the interface cuts *** aim to get a sharp interface method that can have second order accuracy in the point-wise *** show the convergence analysis by splitting errors into several *** numerical examples are presented to confirm the convergence analysis.

关键词： 3D anisotropic PDE Cartesian meshes Finite element method Finite difference method Maximum preserving IIM Convergence analysis

An Augmented IB Method&Analysis for Elliptic BVP on Irregular Domains

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Computer Modeling in Engineering & Sciences 2019年第4期119卷 63-72页

作者： Zhilin Li baiying dong Fenghua Tong Weilong Wang CRSC&Department of Mathematics North Carolina State UniversityRaleighNC 27695-8205USA School of Mathematics and Statistics Ningxia UniversityYinchuan750021China College of Mathematics and System Sciences Xinjiang UniversityUrumqi830046China

The immersed boundary method is well-known,popular,and has had vast areas of applications due to its simplicity and robustness even though it is only first order accurate near the *** this paper,an immersed boundary-augmented method has been developed for linear elliptic boundary value problems on arbitrary domains(exterior or interior)with a Dirichlet boundary *** new method inherits the simplicity,robustness,and first order convergence of the IB method but also provides asymptotic first order convergence of partial *** examples are provided to confirm the analysis.

关键词： Immersed boundary method augmented approach convergence derivative computing

一类均匀介质腔体模型电磁散射问题的快速求解算法

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宁夏师范学院学报 2014年第6期35卷 24-30页

作者：董白英宁夏师范学院数学与计算机科学学院宁夏固原756000

针对矩形腔体模型的散射问题,基于双线性元离散,提出了一种有效的快速求解算法.通过傅里叶变换和高斯消去法将离散方程简化为维数较低的界面方程,对界面方程给出了一个有效的预处理子空间迭代法,数值试验说明了算法的有效性.

关键词：电磁散射问题双线性元预处理

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二维椭圆界面问题的瀑布型多重网格方法

宁夏师范学院学报 2017年第6期38卷 13-20页

作者：董白英宁夏师范学院数学与计算机科学学院宁夏固原756000

对于二维椭圆界面问题,基于浸入界面有限元方法离散,提出了一类瀑布型多重网格方法.对界面曲线附近的节点,结合界面曲线信息和跳跃条件构造了一类新的高精度插值算子,并基于新插值算子建立瀑布型多重网格法.数值实验说明了新瀑布型多重... 详细信息

对于二维椭圆界面问题,基于浸入界面有限元方法离散,提出了一类瀑布型多重网格方法.对界面曲线附近的节点,结合界面曲线信息和跳跃条件构造了一类新的高精度插值算子,并基于新插值算子建立瀑布型多重网格法.数值实验说明了新瀑布型多重网格法的稳健性和有效性,并且在相同的迭代终止条件、光滑算子和粗网格算子的条件下,比较了基于四类插值算子的瀑布型多重网格法的收敛速度.

关键词：浸入界面有限元法高精度插值算子瀑布型多重网格法

Resonance mechanism of flapping wing based on fluid structure interaction simulation

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Chinese Journal of Aeronautics 2024年第5期37卷 243-262页

作者： Yueyang GUO Wenqing YANG Yuanbo dong dong XUE National Key Laboratory of Science and Technology on Aerodynamic Design and Research School of AeronauticsNorthwestern Polytechnical UniversityXi'an 710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China Yangtze River Delta Research Institute of Northwestern Polytechnical University Taicang 215400China

Certain insect species have been observed to exploit the resonance mechanism of their *** order to achieve resonance and optimize aerodynamic performance,the conventional approach is to set the flapping frequency of flexible wings based on the Traditional Structural Modal(TSM)***,there exists controversy among researchers regarding the relationship between frequency and aerodynamic *** that the structural response of wings can be influenced by the surrounding air vibrations,an analysis known as Acoustic Structure Interaction Modal(ASIM)is introduced to calculate the resonant *** this study,Fluid Structure Interaction(FSI)simulations are employed to investigate the aerodynamic performance of flapping wings at modal frequencies derived from both TSM and ASIM *** performance is evaluated for various mass ratios and frequency ratios,and the findings indicate that the deformation and changes in vortex structure exhibit similarities at mass ratios that yield the highest aerodynamic ***,the flapping frequency associated with the maximum time-averaged vertical force coefficient at each mass ratio closely aligns with the ASIM frequency,as does the frequency corresponding to maximum ***,the ASIM analysis can provide an effective means for predicting the optimal flapping frequency for flexible ***,it enables the prediction that flexible wings with varying mass ratios will exhibit similar deformation and vortex structure *** paper offers a fresh perspective on the ongoing debate concerning the resonance mechanism of Flexible Flapping Wings(FFWs)and proposes an effective methodology for predicting their aerodynamic performance.

关键词： Flexible Flapping Wing(FFW) Acoustic Structure Interaction Modal(ASIM) Fluid Structure Interaction(FSI) Resonance mechanism Aerodynamic performance

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G-h分布下的VaR估计及应用

宁夏师范学院学报 2015年第3期36卷 75-79页

作者：丁芳董白英宁夏师范学院数学与计算机科学学院宁夏固原756000

讨论了基于G-h分布下的VaR计算和分布的一些特性.研究证明,g-h分布下的VaR估计比在极值理论下的VaR能更准确的描述资产收益率的变化,具有很大的柔性.

关键词： VaR G-h分布极值理论阀值

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g-h分布和极值理论下的VaR估计

咸阳师范学院学报 2015年第4期30卷 34-36页

作者：丁芳董白英宁夏师范学院数学与计算机科学学院宁夏固原756000

采用国外学者提出的一种g-h分布,讨论了基于g-h分布下的VaR计算和分布的一些特性,经过研究证明,g-h分布下的VaR估计比在极值理论下的VaR更能准确地描述资产收益率的变化,具有很大的柔性。

关键词： VaR g-h分布极值理论阈值

Finite-time Prescribed Performance Time-Varying Formation Control for Second-Order Multi-Agent Systems With Non-Strict Feedback Based on a Neural Network Observer

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 1039-1050页

作者： Chi Ma Dianbiao dong the School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China

This paper studies the problem of time-varying formation control with finite-time prescribed performance for nonstrict feedback second-order multi-agent systems with unmeasured states and unknown *** eliminate nonlinearities,neural networks are applied to approximate the inherent dynamics of the *** addition,due to the limitations of the actual working conditions,each follower agent can only obtain the locally measurable partial state information of the leader *** address this problem,a neural network state observer based on the leader state information is ***,a finite-time prescribed performance adaptive output feedback control strategy is proposed by restricting the sliding mode surface to a prescribed region,which ensures that the closed-loop system has practical finite-time stability and that formation errors of the multi-agent systems converge to the prescribed performance bound in finite ***,a numerical simulation is provided to demonstrate the practicality and effectiveness of the developed algorithm.

关键词： Finite-time control multi-agent systems neural network prescribed performance control time-varying formation control

Decision and Coordination in a Closed-Loop Supply Chain with Product Recycling Under Different Low-Carbon Regulations

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Journal of the Operations Research Society of China 2024年第3期12卷 695-728页

作者： Qian-dong dong Hai-Wen Xu School of Management and Engineering Nanjing UniversityNanjing210093JiangsuChina School of Science Civil Aviation Flight University of ChinaGuanghan618307SichuanChina

The implementation of recycling activity is of great significance to closed-loop supply chain ***’environmental awareness and governmental subsidy are considered in the two-echelon closed-loop supply *** types of decision-making structures are proposed under different carbon emission *** subsidy sharing mechanism is designed to resolve the channel members’conflict caused by double *** paper provides insight into the effect of environmental awareness and government subsidy under different low-carbon regulations on the supply chain benefit and social welfare via the game *** analysis results display that the government subsidy and subsidy sharing mechanism are profitably beneficial to the whole supply chain and social ***,a noteworthy result reveals that social welfare is not always directly proportional to consumers’environmental *** welfare decreases slightly with the increase in consumers’environmental awareness when consumers’environmental awareness is ***,social welfare will be significantly improved when consumers’environmental awareness increases beyond a certain threshold.

关键词： Closed-loop supply chain Recycling Coordination Social welfare Game theory Carbon emissions