• 대한수학회보
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• 제57권2호
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• pp.393-406
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• 2020

We analyze a posteriori error estimator for the conforming P2 finite element on triangular meshes which is based on the solution of local Neumann problems. This error estimator extends the one for the conforming P1 finite element proposed in [4]. We prove that it is asymptotically exact for the Poisson equation when the underlying triangulations are mildly structured and the solution is smooth enough.

• Steel and Composite Structures
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• 제14권1호
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• pp.1-20
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• 2013

This paper presents the formulation for a novel force-based 1-D compound-element that captures both material and second order P-${\Delta}$ nonlinearities in steel frames. At the nodal points, the element is attached to nonlinear rotational and a translational springs which represent the flexural and axial stiffness of the connections respectively. By decomposing the total strain in the material as well as the generalised displacements of the flexible connections to their elastic and inelastic components, a secant solution strategy based on a direct iterative scheme is introduced and the corresponding solution strategy is outlined. The strain and slope of the deformed element are assumed to be small; however the equilibrium equations are satisfied for the deformed element taking account of P-${\Delta}$ effects. The formulation accuracy and efficiency is verified by some numerical examples on the nonlinear static, cyclic and dynamic analysis of steel frames.

• 대한기계학회논문집B
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• 제25권11호
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• pp.1581-1593
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• 2001

An efficient variable-reordering method for finite element meshes is used and the effect of variable-reordering is investigated. For the element renumbering of unstructured meshes, Cuthill-McKee ordering is adopted. The newsy reordered global matrix has a much narrower bandwidth than the original one, making the ILU preconditioner perform bolter. The effect of variable reordering on the convergence behaviour of saddle point type matrix it studied, which results from P2/P1 element discretization of the Navier-Stokes equations. We also propose and test 'level(0) preconditioner'and 'level(2) ILU preconditioner', which are another versions of the existing 'level(1) ILU preconditioner', for the global matrix generated by P2/P1 finite element method of incompressible Navier-Stokes equations. We show that 'level(2) ILU preconditioner'performs much better than the others only with a little extra computations.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제9권1호
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• pp.17-29
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• 2005

In this paper we consider finite element methods for nonlinear hyperbolic integro-differential problems defined in ${\Omega}\;{\subset}\;R^d(d\;{\leq}\;4)$. A new initial approximation of $u_t(0)$ is taken. Optimal order error estimates in $L_p$ for $2\;{\leq}\;p\;{\leq}\;{\infty}$ are established for arbitrary order finite element. One order superconvergence in $W^{1,p}$ for $2\;{\leq}\;p\;{\leq}\;{\infty}$ are demonstrated as well.

• 대한수학회논문집
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• 제34권4호
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• pp.1069-1078
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• 2019

Let R be a ring with identity and P(R) denote the prime radical of R. An element r of a ring R is called strongly P-clean, if there exists an idempotent e such that $r-e=p{\in}P$(R) with ep = pe. In this paper, we determine necessary and sufficient conditions for an element of a trivial Morita context to be strongly P-clean.

• Korean Journal of Mathematics
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• 제6권1호
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• pp.17-26
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• 1998

In this paper, we briefly study the condition number of stiffness matrix with $h$-version and analyze it with $p$-version of the finite element method.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.631-632
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• 2010

• 전산구조공학
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• 제9권1호
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• pp.33-45
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• 1996

전단변형을 고려한 보강재요소를 p-version 유한요소법을 사용하여 정식화 하였다. 적분형 르장드르 다항식으로부터 유도된 계층적 C/sup 0/-형상함수를 5자유도를 갖는 보강재와 평판요소의 조립강성도 행렬을 정의하는데 사용하였다. 보강재와 평판의 접속부에서 변위의 적합성을 만족시키기 위해 적절한 좌표변환행렬을 사용하여 국부좌표계에서 정의된 보강재의 강성도 행렬을 기준좌표계인 평판의 좌표계로 변환시켰다. 평판의 기준좌표계에 대한 보강재의 방향과 편심효과를 설명할 수 있는 변환행렬이 평판과 보강재의 접속부에서의 국부적인 거동과 합성구조로 된 보강판에서 평판과 보강재가 감당하는 상대적인 강도 분담을 파악하기 위해 사용되었다. p-version 유한요소법에 의한 결과를 기존의 연구결과와 비교하였으며, 특히 h-version유한요소해석 프로그램인 MICROFEAP-II의 결과를 비교하였다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 1995년도 Proceedings of special lectures on Molecular Biological Approaches to Plant Disease National Agricultural Science and Technology Institute Suwon, Korea
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• pp.1-19
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• 1995

The plasmid pJEL 101 contains a highly repetitive element from the genome of Xanthomonas oryae pv. oryzae that has properties of an insertional element. The insertional nature of the element, hereto referred to as IS203, was confirmed by molecular analyses of the element and three related elements that were isolated from X. oryzae. The related sequences were isolated on the basis of transposition to the transposon-trapping vector pL3SAC and hybridization with pJEL101. The trapped elements (IS203a, IS203b, and IS203c) were each composed of 1,055 base pairs with 25 base terminal inverted repeats. The elements caused a three base pair target site duplication at the site of insertion in the sacRB gene. The sequence of pJEL 101 has 96% base pair identity with IS203a and 99% identity with IS203a and IS203c but lacks three nucleotides of the consensus left terminal repeat. IS203b has the same DNA sequences as IS203c but is inserted ito the sacRB gene in the opposite orientation. The longest open reading frame of IS203a could code for a protein of 318 amino acids and molecular weight of 37, 151. A search of the Genbank database revealed that IS203 has 51% identity with 909 nucleotides of IS4551 from Escherichia coli. The predicted protein of ORF1 has 40% and 30% amino acid identity to the ORF1 of Tn4551 and the transposase of IS30, respectively.

• 한국전산구조공학회논문집
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• 제22권1호
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• pp.117-124
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• 2009

2차원 포텐셜 문제를 해석하기 위해 고차의 르장드르 형상함수에 기초를 둔 p-수렴 경계요소법이 제안되었다. p-수렴 경계요소법은 종래의 경계요소법에서 사용되는 형상함수와 성질이 다른 르장드르 다항식을 형상함수로 사용한다. p-수렴 유한요소법과 마찬가지로 고차의 형상함수에 따른 절점의 위치가 경계상에서 정해지지 않는다. 따라서 형상함수가 증가함에 따라 선형방정식을 구성하기 위한 수단으로 선점법을 이용하였다. p-수렴 경계요소법에서 선점법은 비대칭 계층적 선점법과 대칭 비계층적 선점법을 선택하여 수치해석을 수행하였다. 선택점들은 형상함수가 증가함에 따라 증가하는 성질을 나타내며 계층적 또는 대칭적으로 선택될 수 있다. p-수렴 경계요소법에서 나타나는 특이 적분항을 계산하기 위해 special numeric quadrature technique와 semi-analytical integration technique를 사용하였다. 사각모서리부에서 특이성을 가지는 L-형 영역문제를 해석한 결과 적은 수의 자유도에서 기존문헌의 결과와 차이가 거의 없는 정도인 $10^{-2}%$단위 이하의 정확도를 보여주었다. 또한 같은 조건에서는 대칭형 선점의 위치를 이용해 계산한 값이 가장 높은 정확도를 보여주었다.