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constrained QUADRILATERAL NONCONFORMING ROTATED Q1 ELEMENT

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Journal of Computational Mathematics 2005年第6期23卷 561-586页

作者： Jun Hu Zhong-ci Shi LSEC ICMSEC Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing 100080 China

In this paper, we define a new nonconforming quadrilateral finite element based on the nonconforming rotated Q1 element by enforcing a constraint on each element, which has only three degrees of freedom. We investigate the consistency, approximation, superclose property, discrete Green＇s function and superconvergence of this element. Moreover, we propose a new postprocessing technique and apply it to this element. It is proved that the postprocessed discrete solution is superconvergent under a mild assumption on the mesh.

关键词： constrained Nonconforming Rotated Q1 element Superconvergence Postprocess

constrained auxiliary particle filtering for bearings-only maneuvering target tracking

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Journal of Systems Engineering and Electronics 2019年第4期30卷 684-695页

作者： ZHANG Hongwei XIE Weixin Automatic Target Recognition Key Laboratory Shenzhen University

To track the nonlinear,non-Gaussian bearings-only maneuvering target accurately online,the constrained auxiliary particle filtering(CAPF)algorithm is *** restrict the samples into the feasible area,the soft measurement constraints are implemented into the update routine via the1 ***,to enhance the sampling diversity and efficiency,the target kinetic features and the latest observations are involved into the *** take advantage of the past and the current measurement information simultaneously,the sub-optimal importance distribution is constructed as a Gaussian mixture consisting of the original and modified priors with the fuzzy weighted *** a result,the corresponding weights are more evenly distributed,and the posterior distribution of interest is approximated well with a heavier *** results demonstrate the validity and superiority of the CAPF algorithm in terms of efficiency and robustness.

关键词： bearings-only maneuvering target tracking soft measurement constraints constrained auxiliary particle filtering(CAPF)

constrained tolerance rough set in incomplete information systems

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CAAI Transactions on Intelligence Technology 2021年第4期6卷 440-449页

作者： Renxia Wan Duoqian Miao Witold Pedrycz School of Mathematics and Inforrmation Scicncc North Minzu UniversityYinchuanNingxiaChina Hongyang Institute for Big Data in Health FuzhouFujianChina Department of Computer Science and Technology Tongi UniversityShanghaiChina Department of Electrical and Computer Engineering University of AlbertaEdmontonCanada

The tolerance rough set is developed as one of the outstanding extensions of the Pawlak's rough set model under incomplete information,and the limited tolerance relation is developed to overcome the problem that objects leniently satisfy the tolerance ***,the classification based on the limited tolerance relationship cannot reflect the matching degree of uncertain information of *** this article,we explore the influence of null values in an incomplete system,and propose the constrained tolerance relation based on the matching degree of uncertain information of *** proposed rough set based on the constrained tolerance relation can provide a more detailed structure of an object class through *** and example analyses further show the rationality and superiority of the proposed model.

关键词： incomplete matching constrained

constrained Brownian Motion of a Single Ellipsoid in a Narrow Channel

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Chinese Physics Letters 2019年第3期36卷 57-60页

作者： Han-Hai Li Zhong-Yu Zheng Yu-Ren Wang National Microgravity Laboratory Institute of Mechanics Chinese Academy of Sciences School of Engineering Sciences University of Chinese Academy of Sciences

We study the Brownian motion of a single ellipsoidal particle diffusing in a narrow channel by video-microscopy measurement. The experiments allow us to obtain the trajectories of ellipsoids and measure the diffusion coefficients. It is found that the channel constraints lead to suppression of the particle motion, especially the perpendicular motion to the channel, and the long axis of the particle tends to be parallel to the channel. A stable stratification phenomenon is observed, which is rarely discussed in studies of spherical particles. We also derive an approximate solution of theoretical prediction with the method of reflections, and obtain numerical simulation results using finite element software. They are proven to be effective by comparing them with the experimental results. All of these indicate that the aspect ratio and size of ellipsoid, the width of channel, and the transverse position distinctly affect the Brownian motion of ellipsoids.

关键词： constrained Brownian Single

constrained instanton and black hole creation

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Science China(Physics,Mechanics & Astronomy) 2004年第3期47卷 293-309页

作者： WU Zhongchao XU Donghui Department of Applied Physics Zhejiang University of Technology Hangzhou 310032 China Department of Applied Physics Zhejiang University of Technology Hangzhou 310032 China

A gravitational instanton is considered as the seed for the creation of a universe. However, there exist too few instantons. To include many interesting phenomena in the framework of quantum cosmology, the concept of constrained gravitational instanton is inevitable. In this paper we show how a primordial black hole is created from a constrained instanton. The quantum creation of a generic black hole in the closed or open background is completely resolved. The relation of the creation scenario with gravitational thermodynamics and topology is discussed.

关键词： quantum cosmology, constrained gravitational instanton, black hole creation, primordial black hole.

Blind adaptive constrained constant modulus algorithms based on unscented Kalman filter for beamforming

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Journal of Central South University 2017年第10期24卷 2342-2352页

作者： QIAN Hua-ming LIU Ke JIAO Zhi-bo MA Jun-da College of Automation Harbin Engineering UniversityHarbin 150001China Hainengda Communication Co. Ltd.Shenzhen 518000China

This work proposes constrained constant modulus unscented Kalman filter(CCM-UKF) algorithm and its low-complexity version called reduced-rank constrained constant modulus unscented Kalman filter(RR-CCM-UKF) algorithm for blind adaptive beamforming. In the generalized sidelobe canceller(GSC) structure, the proposed algorithms are devised according to the CCM criterion. Firstly, the cost function of the constrained optimization problem is transformed to suit the Kalman filter-style state space model. Then, the optimum weight vector of the beamformer can be estimated by using the recursive formulas of UKF. In addition, the a priori parameters of UKF(system and measurement noises) are processed adaptively in the implementation. Simulation results demonstrate that the proposed algorithms outperform the existing methods in terms of convergence speeds, output signal-tointerference-plus-noise ratios(SINRs), mean-square deviations(MSDs) and robustness against steering mismatch.

关键词： constrained constant modulus criterion blind beamforming unscented Kalman filter generalized sidelobe canceller

Unfolding the structural stability of nanoalloys via symmetry-constrained genetic algorithm and neural network potential

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npj Computational Materials 2022年第1期8卷 1135-1145页

作者： Shuang Han Giovanni Barcaro Alessandro Fortunelli Steen Lysgaard Tejs Vegge Heine Anton Hansen Department of Energy Conversion and Storage Technical University of DenmarkFysikvej2800Kgs.LyngbyDenmark CNR-ICCOM&IPCF Consiglio Nazionale delle Ricerchevia G.Moruzzi 156124PisaItaly

The structural stability of nanoalloys is a challenging research subject due to the complexity of size,shape,composition,and chemical *** genetic algorithm is a popular global optimization method that can efficiently search for the ground-state nanoalloy ***,the algorithm suffers from three significant limitations:the efficiency and accuracy of the energy evaluator and the algorithm’s *** we describe the construction of a neural network potential intended for rapid and accurate energy predictions of Pt-Ni nanoalloys of various sizes,shapes,and *** further introduce a symmetry-constrained genetic algorithm that significantly improves the efficiency and viability of the algorithm for realistic size *** combination of the two allows us to explore the space of homotops and compositions of Pt-Ni nanoalloys consisting of up to 4033 atoms and quantitatively report the interplay of shape,size,and composition on the dominant chemical ordering patterns.

关键词： structure symmetry constrained

Hohmann transfer via constrained optimization

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Frontiers of Information Technology & Electronic Engineering 2018年第11期19卷 1444-1458页

作者： Li XIE Yi-qun ZHANG Jun-yan XU State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources School of Control and Computer EngineeringNorth China Electric Power UniversityBeijing 102206China Beijing Institute of Electronic Systems Engineering Beijing 100854China

Inspired by the geometric method proposed by Jean-Pierre MAREC, we first consider the Hohmann transfer problem between two coplanar circular orbits as a static nonlinear programming problem with an inequality constraint. By the Kuhn-Tucker theorem and a second-order sufficient condition for minima, we analytically prove the global minimum of the Hohmann transfer. Two sets of feasible solutions are found: one corresponding to the Hohmann transfer is the global minimum and the other is a local minimum. We next formulate the Hohmann transfer problem as boundary value problems, which are solved by the calculus of variations. The two sets of feasible solutions are also found by numerical examples. Via static and dynamic constrained optimizations, the solution to the Hohmann transfer problem is re-discovered, and its global minimum is analytically verified using nonlinear programming.

关键词： Hohmann transfer Nonlinear programming constrained optimization Calculus of variations

A 3D Nonhydrostatic Compressible Atmospheric Dynamic Core by Multi-moment constrained Finite Volume Method

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Advances in Atmospheric Sciences 2019年第10期36卷 1129-1142页

作者： Qingchang QIN Xueshun SHEN Chungang CHEN Feng XIAO Yongjiu DAI Xingliang LI College of Global Change and Earth System Science Beijing Normal University Beijing 100875 China Center of Numerical Weather Predication China Meteorological Administration Beijing 100081 China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi’an Jiaotong University Xi’an 710049 China Department of Mechanical Engineering Tokyo Institute of Technology Tokyo 226-8502 Japan School of Atmospheric Sciences Sun Yat-Sen University Guangzhou 510275 China Beijing Meteorological Observatory Beijing 100089 China

A 3D compressible nonhydrostatic dynamic core based on a three-point multi-moment constrained finite-volume (MCV) method is developed by extending the previous 2D nonhydrostatic atmospheric dynamics to 3D on a terrainfollowing grid. The MCV algorithm defines two types of moments: the point-wise value (PV) and the volume-integrated average (VIA). The unknowns (PV values) are defined at the solution points within each cell and are updated through the time evolution formulations derived from the governing equations. Rigorous numerical conservation is ensured by a constraint on the VIA moment through the flux form formulation. The 3D atmospheric dynamic core reported in this paper is based on a three-point MCV method and has some advantages in comparison with other existing methods, such as uniform third-order accuracy, a compact stencil, and algorithmic simplicity. To check the performance of the 3D nonhydrostatic dynamic core, various benchmark test cases are performed. All the numerical results show that the present dynamic core is very competitive when compared to other existing advanced models, and thus lays the foundation for further developing global atmospheric models in the near future.

关键词： multi-moment constrained finite-volume method nonhydrostatic dynamic core topography height-based terrain-following coordinate