• Journal of computational fluids engineering
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• v.5 no.1
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• pp.43-59
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• 2000

Characteristic boundary conditions are discussed in conjunction with a flux-difference splitting formulation as modified from Roe's linearization. Details of how one can implement the characteristic boundary conditions which are made compatible with the interior point formulation are described for different types of boundaries including subsonic outflow and adiabatic wall. The validity of boundary conditions are demonstrated through computation of transonic airfoil, supersonic ogive-cylinder, hypersonic cylinder, and S-duct internal flows. The computed wall pressure distributions are compared with published experimental and computed data. Objectives of this paper are thus to give insight of formulation procedure of a flux-difference splitting method and to pave ways for other users to adopt present boundary procedure on their numerical methods.

• Proceedings of the Korea Society for Simulation Conference
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• 1997.04a
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• pp.115-119
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• 1997

본 논문은 해상에서 발생될 수 있는 기름 유출 사고시 효과적 방제의 지원을 위한 오염원 확산 예측 시스템의 개발을 주목적으로 한다. 이를 위하여, 격자형 공간 DEVS 모델 링 방법론을 이용한 SOS(Save Our Sea) 시스템을 개발하였다. 기존의 해양오염 예측 시스 템들이 대부분 해석적 기법에 의존하는데 비해 제안된 시스템은 격자형 공간 모델링을 이용 한 시뮬레이션 기법으로서 전체 해양을 Cell 단위의 공간으로 분할하고, Cellrks의 결합관계 는 Name-Directed Coupling을 적용함으로서 시스템 설계상의 효율성과 유연성을 제공한 다. 제안된 시스템은 기름유출사고의 발생시 오염원 확산에 영향을 주는 각종 벡터 변수값 들에 따른 해양 오염 물질의 확산 분포를 예측함과 동시에 확산에 영향을 주는 많은 벡터 값들이 모니터링 정보를 함께 제공함으로서 해양 오염 방제 및 환경 보존에 효과적으로 적 용될 수 있을 것으로 기대된다.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.3
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• pp.290-297
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• 2004

The control laws for cart-pole system are studied to see the schemes on which the control laws are made. Also, the odd symmetry of the relation between the output of the control laws and the system state vector is observed. Utilizing the symmetry in quantizing the system state variables and implementing the control laws into look-up table is discussed. Then, a CMAC is trained for a nonlinear control law for a cart-pole system such that the symmetry is conserved and its learning performance is evaluated. It is found that utilizing the symmetry is to reduce the memory requirement as well as the training period while improving the learning quality in terms of preserving the symmetry.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.1
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• pp.31-40
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• 2017

Absolute nodal coordinate formulation was developed in the mid-1990s, and is used in the flexible dynamic analysis. In the process of deriving the equation of motion, if the order of polynomial referring to the displacement field increases, then the degrees of freedom increase, as well as the analysis time increases. Therefore, in this study, the primary objective was to reduce the analysis time by transforming the dimensional equation of motion to a non-dimensional equation of motion. After the shape function was rearranged to be non-dimensional and the nodal coordinate was rearranged to be in length dimension, the non-dimensional mass matrix, stiffness matrix, and conservative force was derived from the non-dimensional variables. The verification and efficiency of this non-dimensional equation of motion was performed using two examples; cantilever beam which has the exact solution about static deflection and flexible pendulum.