• 산업기술연구
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• 제9권
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• pp.109-117
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• 1989

In the finite element analysis of semiconductor devices analysis, the solution often be diverged due to the numerical instability of discretized equations. To overcome this problems, a noble finite element code which guarantees a successful convergence is developed. The factor of divergence in the current continuity equation of semiconductor governing equations is derived using stability test and an adaptive mesh refine scheme is introduced to eliminates the divergence properties. A test calculation of GaAs MESFET model reveals that the proposed scheme has a robust self-convergence property and is suitable for the semiconductor devices analysis.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제7권2호
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• pp.95-111
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• 2003

BDM mixed methods are obtained for a good approximation of velocity for flow equations. In this paper, we study an implementation issue of solving the algebraic system arising from the BDM mixed finite elements. First we discuss post-processing based on the use of Lagrange multipliers to enforce interelement continuity. Furthermore, we establish an equivalence between given mixed methods and projection finite element methods developed by Chen. Finally, we present the implementation of the first order BDM on rectangular grids and show it is as simple as solving the pressure equation.

• Kyungpook Mathematical Journal
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• 제62권4호
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• pp.615-640
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• 2022

In this paper, we investigate a time-dependent double obstacle problem associated with the model of European call option pricing with transaction costs. We prove the existence and uniqueness of a W^2,1_p,loc solution to the problem. We then characterize the behavior of the free boundaries in terms of continuity and values of limit points.

• 한국유통학회지:유통연구
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• 제15권1호
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• pp.73-101
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• 2010

본 연구는 유대강도, 공유된 목표, 신뢰와 같은 사회자본이 경제적 성과와 비경제적 성과인 관계지속의도에 미치는 영향에 대하여 부산지역 프랜차이즈 가맹점을 대상으로 공변량 구조방정식모형을 통하여 실증분석하였다. 그 결과 첫째, 유대강도는 관계지속의도에 직접적인 영향을 미치지는 못하지만 신뢰와 경제적 성과를 매개로 간접적으로 긍정적인 영향을 미치는 것으로 나타났다. 둘째, 공유된 가치는 관계지속의도에 직접적인 영향은 물론 신뢰를 매개로 간접적으로 긍정적인 영향을 미치는 것으로 나타났다. 하지만 공유된 목표가 경제적 성과를 매개로 하여 관계지속의도에 영향을 미치지 않는 것으로 나타났다. 마지막으로 이러한 결과들을 토대로 본 연구의 이론적 실무적 시사점을 제시하였다.

• 한국기계연구소 소보
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• 통권9호
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• pp.141-151
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• 1982

An iterative procedure for the calculation of the thick axisymmetric boundary layer and wake near the stern of a body of revolution is presented. Procedure consists of the potential flow calculation by a method of the integral equation of first kind and the calculation of boundary layer and wake by a differential me¬thod of the boundary layer theory. Additionally, higher order terms are included in the conventional momentum equations and continuity equation for the consider¬ation of the characteristics of axisymmetric flow different from the one of two dimentional flow and the thick boundary layer. These solutions are matched at the edge of boundary layer and wake. The results obtained by the present me¬thod are compared with the experimental data and it is found that the nominal wake distribution at the propeller plane of a axisymmetric body is in good agree¬ment with the experiment.

• 한국해양공학회지
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• 제13권4호통권35호
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• pp.1-9
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• 1999

일차원 및 이차원의 단순한 문제에 대하여 계층 요소를 사용한 혼합 차수 유한 요소해의 정확성 및 수렴성을 조사하였다. 이러한 작업은 임의의 차수를 가진 블록들을 조합하여 요소를 구성함으로서 이루어질 수 있다. 블록간의 연결성이 유지될 수 있는 블록의 구성과 요소 생성에 대하여는 코드개발과 관련하여 설명하고 있으며, 서로 다른 차수를 가진 인접 블록간의 해의 연속성에 대하여는 계층 요소의 구성과 관련하여 서술되었다. 수치적 결과는 블록의 차수를 잘 선택함으로서 유한 요소해의 수렴성과 정확성을 증가시킬 수 있음을 보여주고 있으며, 고차 요소 영역을 너무 많이 할당하여 선형 요소의 영역이 너무 적을 경우에는 경계 조건에 따라 오차가 내부로 전파됨을 보여준다. 또한 세분화된 요소에 대한 고차 보간의 경우, 해의 수렴성이 저해될 수 있음이 발견되었다.

• 한국전산유체공학회지
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• 제13권3호
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• pp.51-61
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• 2008

The SMAC (Simplified Marker And Cell) algorithm is extended for an application to thermal non-equilibrium two-phase flows in light water nuclear reactors (LWRs). A two-fluid three-field model is adopted and a multi-dimensional unstructured grid is used for complicated geometries. The phase change and the time derivative terms appearing in the continuity equations are implemented implicitly in a pressure correction equation. The energy equations are decoupled from the momentum equations for faster convergence. The verification of the present numerical method was carried out against a set of test problems which includes the single and the two-phase flows. The results are also compared to those of the semi-implicit ICE method, where the energy equations are coupled with the momentum equation for pressure correction.

• Journal of Advanced Marine Engineering and Technology
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• 제29권7호
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• pp.729-735
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• 2005

This paper has dealt with the characteristics of mass and heat transfer of vertical flat plate with free convection. The theory of similarity transformations applied to the momentum and energy equations for free convection. To derive the similarity equation of mass transfer. the equation for conservation of species was added to the continuity. momentum and energy equations. The momentum, energy and species equations set numerically to obtain the velocity, temperature and mass fraction of species as dimensionless. For cases where momentum transport dominates, the thermal boundary layers are shorter than the momentum boundary layer. The relationships between momentum, energy and species were clarified from this study.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.401-406
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• 2008

This paper proposes a method to calculate the static characteristics of the FDBs with the curved surface. The general Reynolds equations are derived for the curved surfaces in the ${\theta}s$ plane. And the Reynolds equation is transformed to the finite element equations by considering the continuity of pressure and flow at the interface between the curved, journal and the thrust bearings. It also includes the Reynolds boundary condition in the numerical analysis to simulate the cavitation phenomenon. The static characteristics of the coupled journal and conical bearings were investigated due to the variation of conical angle. It shows that the conical angle is one of the important design parameters affecting the static and dynamic characteristics of FBBs.

• 한국해양공학회지
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• 제10권3호
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• pp.96-104
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• 1996

Hamilton's principle is used to derive Euler-Lagrange equations for free surface flow problems of incompressible ideal fluid. The velocity field is chosen to satisfy the continuity equation a priori. This approach results in a hierarchial set of governing equations consist of two evolution equations with respect to two canonical variables and corresponding boundary value problems. The free surface elevation and the Lagrange's multiplier are the canonical variables in Hamilton's sense. This Lagrange's multiplier is a velocity potential defined on the free surface. Energy is conserved as a consequence of the Hamiltonian structure. These equations can be applied to waves in water of finite depth including generalization of Hamilton's equations given by Miles and Salmon.