• 한국수자원학회논문집
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• 제55권12호
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• pp.991-998
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• 2022

본 연구의 목적은 넓은 지역의 고해상도 홍수모의를 위해서 2차원 모형의 GPU (Graphics Processing Unit) 가속 모의기법을 개발하고 이에 대한 효과를 평가하는 것이다. 음해법을 적용하고 있는 정형 사각형 격자 기반의 2차원 모형인 G2D (Grid based 2-Dimensional land surface flood model) 모형에서 CUDA를 이용하여 GPU 가속 모의 기법을 개발하였다. 개발된 기법을 진주시 홍수모의에 적용하였다. 모의 도메인의 공간해상도는 10 m × 10 m이고, 계산되는 격자의 개수는 총 5,090,611개이다. 홍수모의는 2019년 10월 태풍 미탁에 의한 홍수 기간에 대해서 수행하였다. 강우레이더 자료를 생성항으로 적용하였으며, 남강댐 일류문 계측 방류량과 진주시(옥산교) 계측 유량을 경계조건으로 적용하였다. 연구결과 진주시 남강에서의 관측수위를 재현할 수 있는 광역 2차원 홍수 모형을 구축할 수 있었다. 또한 GPU 가속 기법의 적용 결과, CPU (Central Processing Unit)를 이용한 순차계산 및 병렬계산에 비해서 빠른 홍수모의가 가능하였다. 본 연구의 결과는 음해법을 적용하고 있는 2차원 범람모형의 GPU 가속 기법의 개발과 광역 지표면 홍수해석에 대한 연구에 기여할 수 있을 것이다.

• 한국해양공학회지
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• 제23권1호
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• pp.38-42
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• 2009

Recently, various particle based simulation techniques, which solve the Navier Stokes and continuity equations, have been developed and applied to complicated engineering problems. However, although progress is being made on their visualization or rendering techniques, these are still insufficient. In this study, to render a smooth configuration for a free surface, a rendering technique was developed that included the generation of density fields from the location information for simulated particles and the creation model for a polygonal surface. The developed rendering technique was applied to the visualization of a dynamic free surface flow interacting with a structure using a particle based simulation technique.

• Water Engineering Research
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• 제2권2호
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• pp.75-87
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• 2001

A new moving boundary technique for leap-frog finite difference numerical mode is proposed for the resonable simulation of coastal inundation over discontinuous topography. The new scheme improves the moving boundary technique developed by Imamura(1996). The present scheme is tested using the analytical solution of Thacker(1981) for the case of free oscillation with moving boundary in a parabolic bowl. Finally, a numerical simulation is conducted for the flooding over a tidal barrier constructed on a simple concave geometry. A general feature of inundation over a discontinuous topography is well described by the numerical model.

• Journal of International Society for Simulation Surgery
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• 제2권2호
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• pp.87-89
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• 2015

Closed reduction using acrylic splints with circummandibular fixation has been known to be useful techniques in pediatric mandibular fractures. However, this technique has some shortcomings, including needs for impression taking or additional laboratory process, which can increase the exposure time of general anesthesia or make an additional sedation visit. Recently, the advancement of computer-aided maxillofacial surgery offers to clinicians to expansion of its application. This case report represents a technique of computer-assisted virtual reconstruction and computer-aided designed splint fabrication in a 2-year-old boy with mandibular body fracture.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2002년도 추계학술대회 논문집
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• pp.115-121
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• 2002

The growth of semiconductor industry attracted to researchers like design, facility technique and making small size chip areas. But nowadays, cause of technology extension and oversupply and price down, yield improvement is the most important point on growth. This paper describes the computer mode]ing technique as the solutions to analyze the problem, to formalize the semiconductor manufacturing process and to build advanced manufacturing environments. The computer models are built referring an existing 8' wafer production line in Korea.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.171-173
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• 2002

This paper presents a power system decomposition technique for digital simulation of large power system. To decompose power system, distributed transmission line model is used. But this model can be used only for long transmission lines. In this paper, capacitor compensation method is proposed to use distributed transmission line model for short transmission line. And case study shows proposed method can be used for effective power system decompositon in digital simulation of large power system.

• 한국시뮬레이션학회논문지
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• 제6권1호
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• pp.61-69
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• 1997

In 3D computer graphics, fractal techniques have been applied to terrain models. Even though fractal models are convenient way to get the data of terrain models, it is not easy to gain the final results by manipulating the data of terrain model. However, by using the object oriented programming techniques, we could reduce the effort of programming job to find the final result. In this paper, a set of classes made by object oriented programming technique is presented. To show the results, the data of a terrain model were made by a fractal technique, namely, the midpoint displacement methods with square lattices of points.

• 한국정보과학회논문지:소프트웨어및응용
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• 제36권6호
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• pp.443-450
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• 2009

시스템 개발 초기 단계에 시스템의 기능적 요구사항이 제대로 반영되었는지를 검사하기 위해 시뮬레이션 기법을 이용한다. 일반적으로 시뮬레이션은 순차도에 나타난 추상적 시나리오를 바탕으로 상태머신을 직접 또는 랜덤으로 수행하는 행태로 진행된다. 시뮬레이션은 분석자가 직접 수행해야 하므로 많은 시간과 노력이 소요된다. 이 논문에서는 순차도 기반의 상태 머신의 시뮬레이션의 자동화 기법을 제공한다. 일반적으로 순차도와 상태머신의 추상화 레벨이 달라서 순차도에서 상세 시뮬레이션 트레이스를 추출하기가 쉽지 않다. 이 연구에서는 상태 머신을 LTS 모델로 변환하여 합성적 분석, 트랜지션 축약 등의 분석 방법을 적용하여 순차도와 동일한 추상화 레벨로 변환한 다음, 시나리오 포함여부를 검사한 후 해당 시나리오의 상세 시뮬레이션 트레이스를 생성한다. 이러한 시뮬레이션 트레이스는 순차도에 기술된 시나리오를 기반으로 시뮬레이션을 자동으로 수행할 뿐만 아니라, 특정 시스템 상태까지 자동 시뮬레이션할 수 있으므로 시뮬레이션을 효율적으로 진행할 수 있다.

• Korea-Australia Rheology Journal
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• 제14권4호
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• pp.161-174
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• 2002

A new technique for numerical calculation of viscoelastic flow based on the combination of Neural Net-works (NN) and Brownian Dynamics simulation or Stochastic Simulation Technique (SST) is presented in this paper. This method uses a "universal approximator" based on neural network methodology in combination with the kinetic theory of polymeric liquid in which the stress is computed from the molecular configuration rather than from closed form constitutive equations. Thus the new method obviates not only the need for a rheological constitutive equation to describe the fluid (as in the original Calculation Of Non-Newtonian Flows: Finite Elements St Stochastic Simulation Techniques (CONNFFESSIT) idea) but also any kind of finite element-type discretisation of the domain and its boundary for numerical solution of the governing PDE's. As an illustration of the method, the time development of the planar Couette flow is studied for two molecular kinetic models with finite extensibility, namely the Finitely Extensible Nonlinear Elastic (FENE) and FENE-Peterlin (FENE-P) models.P) models.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1999년도 춘계학술대회 논문집
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• pp.70-79
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• 1999

Importance Sampling (IS) has been applied to accelerate the occurrence of rare events. However, it has a drawback of effective biasing scheme to make the estimator from IS unbiased. Adaptive Importance Sampling (AIS) employs an estimated sampling distribution of IS to the systems of interest during the course of simulation. We propose Nonparametric Adaptive Importance Sampling (NAIS) technique which is nonparametrically modified version of AIS and test it to estimate a probability of rare event in M/M/1 queueing model. Comparing with classical Monte Carlo simulation, the computational efficiency and variance reductions gained via NAIS are substantial. A possible extension of NAIS regarding with random number generation is also discussed.