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Dynamic modeling and parameter identification of a gun saddle ring

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Defence Technology（防务技术） 2020年第2期16卷 325-333页

作者： Tong Lin Lin-fang Qian Qiang Yin Shi-yu Chen Tai-su Liu School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing210094China

In this study,a theoretical nonlinear dynamic model was established for a saddle ring based on a dynamic force analysis of the launching process and the structure according to contact-impact *** ADAMS software was used to build a parameterized dynamic model of the saddle ring.A parameter identification method for the ring was proposed based on the particle swarm optimization algorithm.A loading test was designed and performed several times at different elevation *** response histories of the saddle ring with different loads were then *** parameters of the saddle ring dynamic model were identified from statistics generated at a 500 elevation angle to verify the feasibility and accuracy of the proposed *** actual loading history of the ring at a 70°elevation angle was taken as the model *** response histories of the ring under these working conditions were obtained through a *** simulation results agreed with the actual ***,the effectiveness and applicability of the proposed dynamic model were verified,and it provides an effective method for modeling saddle rings.

关键词： Gun saddle ring Dynamic response Parameter identification Particle swarm optimization

IMPROVED RELAXED POSITIVE-DEFINITE AND SKEW-HERMITIAN SPLITTING PRECONDITIONERS FOR saddle POINT PROBLEMS

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Journal of Computational Mathematics 2019年第1期37卷 95-111页

作者： Yang Cao Zhiru Ren Linquan Yao School of Transportation Nantong UniversityNantong 226019China School of Statistics and Mathematics Central University of Finance and Economics Beijing 100081China School of Urban Rail Transportation Soochow UniversitySuzhou 215006China

We establish a class of improved relaxed positive-definite and skew-Hermitian splitting (IRPSS)preconditioners for saddle point *** preconditioners are easier to be implemented than the relaxed positive-definite and skew-Hermitian splitting (RPSS) preconditioner at each step for solving the saddle point *** study spectral properties and the minimal polynomial of the IRPSS preconditioned saddle point matrix.A theoretical optimal IRPSS preconditioner is also obtained,Numerical results show that our proposed IRPSS preconditioners are convergence rate of the GMRES method superior to the existing ones in accelerating the for solving saddle point problems.

关键词： saddle point problems Preconditioning RPSS preconditioner Eigenvalues Krylov subspace method

Lagrangian duality and saddle points for sparse linear programming

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Science China Mathematics 2019年第10期62卷 2015-2032页

作者： Chen Zhao Ziyan Luo Weiyue Li Houduo Qi Naihua Xiu Department of Mathematics Beijing Jiaotong UniversityBeijing100044China State Key Lab of Rail Trac Control and Safety Beijing Jiaotong UniversityBeijing100044China School of Mathematics University of SouthamptonSouthampton SO171BJUK

The sparse linear programming(SLP) is a linear programming problem equipped with a sparsity constraint, which is nonconvex, discontinuous and generally NP-hard due to the combinatorial property *** this paper, by rewriting the sparsity constraint into a disjunctive form, we present an explicit formula of the Lagrangian dual problem for the SLP, in terms of an unconstrained piecewise-linear convex programming problem which admits a strong duality under bi-dual sparsity consistency. Furthermore, we show a saddle point theorem based on the strong duality and analyze two classes of stationary points for the saddle point problem. At last,we extend these results to SLP with the lower bound zero replaced by a certain negative constant.

关键词： sparse linear programming Lagrangian dual problem strong duality saddle point theorem optimality condition

Coherence-Resonance-Induced Neuronal Firing near a saddle-Node and Homoclinic Bifurcation Corresponding to Type-I Excitability

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Chinese Physics Letters 2011年第9期28卷 62-65页

作者： JIA Bing GU Hua-Guang LI Yu-Ye School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092 College of Life Science Shaanxi Normal UniversityXi'an 710062

Excitability is an essential characteristic of excitable media such as nervous and cardiac *** types of neuronal excitability are related to different bifurcation *** simulate the coherence resonance effect near a saddle-node and homoclinic bifurcation corresponding to type-I excitability in a theoretical neuron model,and recognize the obvious features of the corresponding firing *** firing patterns are discovered in rat hippocampal CA1 pyramidal *** results are not only helpful for understanding the dynamics of the saddle-node bifurcation and type-I excitability in a realistic nervous system,but also provide a practical indicator to identify types of excitability and bifurcation.

关键词： bifurcation bifurcation saddle

Finite element method based on combination of "saddle point" variational formulations

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Science China(Technological Sciences) 1997年第3期40卷 285-300页

作者：周天孝 Aeronautical Computing Technology Research Institute Xi'an 710068 China

A modified mixed/hybrid finite element method, which is no longer required to satisfy the Babuska-Brezzi condition, is referred to as a stabilized method Based on the duality of vanational principles in solid mechanics, a new type of stabilized method, called the combinatorially stabilized mixed/hybrid finite element method, is presented by weight-averaging both the primal and the dual "saddle-point" schemes. Through a general analysis of stability and convergence under an abstract framework, it is shown that for the methods only an inf-sup inequality much weaker than Babuska-Brezzi condition needs to be satisfied. As a concrete application, it is concluded that the combinatorially stabilized Raviart and Thomas mixed methods permit the C -elements to replace the H(div; Ω)-elements.

关键词： mixed/hybrid finite element stabilized method error estimates saddle point problem.

THE CHARACTERIZATION OF EFFICIENCY AND saddle POINT CRITERIA FOR MULTIOBJECTIVE OPTIMIZATION PROBLEM WITH VANISHING CONSTRAINTS

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Acta Mathematica Scientia 2019年第2期39卷 382-394页

作者： Anurag JAYSWAL Vivek SINGH Department of Applied Mathematics Indian Institute of Technology (Indian School of Mines)

In this article, we focus to study about modified objective function approach for multiobjective optimization problem with vanishing constraints. An equivalent η-approximated multiobjective optimization problem is constructed by a modification of the objective function in the original considered optimization problem. Furthermore, we discuss saddle point criteria for the aforesaid problem. Moreover, we present some examples to verify the established results.

关键词： multiobjective optimization problem with vanishing constraints efficient solution invexity η-Lagrange function saddle point

ON THE STRUCTURE OF THE INTEGRAL SURFACES NEAR A HIGH ORDER FOCUS AND saddle

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Chinese Science Bulletin 1991年第13期36卷 1139-1140页

作者：赵怀忠 Institute of Applied Mathematics Academia Sinica Beijing 100080 PRC

First we consider the singular point (0, 0) of a complex analytic system with real

关键词： analytic singular FOCUS formulae saddle

THE MORSE INDEX OF A saddle POINT

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Systems Science and Mathematical Sciences 1989年第1期2卷 32-39页

作者：刘嘉荃 Graduate School University of Science and Technology of ChinaBeijingChina

This paper is devoted to clarifying the relationship between the classical Morse theory andthe Mountain Pass Lemma via the local linking *** is shown that for a C^1-function f with alocal linking,the m-thcritical group is nontrivial,where m is the Morse *** with thebehavior of f at infinity,this result can be used to offer the existence of nontrivial critical points.

关键词： saddle point Morse theory Mountain Pass Lemma local linking

CHARACTERIZATIONS OF PROPER EFFICIENT SOLUTIONS IN TERMS OF saddle POINTS AND DUALITY

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Systems Science and Mathematical Sciences 1992年第1期5卷 9-18页

作者： LI Shizheng (Shandong Normal University,Jinan 250014,China) 山东师范大学山东济南

In this paper we characterize the proper efficient solution of a mul-tiobjective programming problem(P)in terms of the saddle point criterion of anew problem(S)and establish a pair of dual problems(S_α)and(D_α)in order todecide the proper efficient solution by the strong *** also give methodof characterization in terms of the saddle point criterion of(P).Finally,we provethat every efficient solution of the matrix linear programming problem is a properefficient solution.

关键词： Efficient solution proper efficient solution saddle point criterion duality perturbation function matrix linear programming problem