• Journal of Mechanical Science and Technology
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• 제19권spc1호
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• pp.395-402
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• 2005

This paper deals with modeling and computer simulation of a full multibody vehicle model for a driving simulator. The multibody vehicle model is based on the recursive formulation and a corresponding simulation code is generated automatically from AUTOCODE, which is a symbolic computation package developed by the authors using MAPLE. The paper describes a procedure for automatically generating a highly efficient simulation code for the full vehicle model, while incorporating realistically modeled components. The following issues have been accounted for in the procedure, including software design for representing a mechanical system in symbolic form as a set of computer data objects, a multibody formulation for systems with various types of connections between bodies, automatic manipulation of symbolic expressions in the multibody formulation, interface design for allowing users to describe unconventional force-and torque-producing components, and a method for accommodating external computer subroutines that may have already been developed. The effectiveness and efficiency of the proposed method have been demonstrated by the simulation code developed and implemented for driving simulation.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3429-3439
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• 2022

The MCS code is a computer code developed by the Ulsan National Institute of Science and Technology (UNIST) for simulation and calculation of nuclear reactor systems based on the Monte Carlo method. The code is currently used to solve two main types of reactor physics problems, namely, criticality problems and radiation shielding problems. In this paper, the radiation shielding capability of the MCS code is validated by simulating some selected SINBAD (Shielding Integral Benchmark Archive and Database) experiments. The whole validation was performed in two ways. Firstly, the functionality and computational rationality of the MCS code was verified by comparing the simulation results with those of MCNP code. Secondly, the validity and computational accuracy of the MCS code was confirmed by comparing the simulation results with the experimental results of SINBAD. The simulation results of the MCS code are highly consistent with the those of the MCNP code, and they are within the 2σ error bound of the experiment results. It shows that the calculation results of the MCS code are reliable when simulating the radiation shielding problems.

• 한국콘텐츠학회논문지
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• 제6권12호
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• pp.155-162
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• 2006

Code Red와 같은 인터넷 웜이 얼마나 심각하게 우리들 일상생활에 영향을 미쳤는지 잘 알려져 있다. 오늘날 인터넷의 고속화와 함께 이러한 웜의 피해는 단기간 내에 발생할 것이 자명하다. 따라서 이러한 웜에 대항하기 위해서 웜의 전파 특성을 분석하는 것이 무엇보다 중요하다. 본 논문에서는 컴퓨터 시뮬레이션을 통해 Code Red 웜의 전파 특성을 분석한다. 특히 Code Red웜 감염 호스트 수에 관한 기존 시뮬레이션 연구 결과가 관측된 자료와 매칭되지 않음을 보이고 이를 해결하기 위해 개선된 시뮬레이션 환경을 제시하였다. 또한 웜에 대한 초기 대응과 감염에 따른 대응이 웜의 전파 속도 변화에 어떠한 영향을 미치는지 그 결과를 보였다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1999년도 학술대회논문집-국제 전기방전 및 플라즈마 심포지엄 Proceedings of 1999 KIIEE Annual Conference-International Symposium of Electrical Discharge and Plasma
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• pp.58-63
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• 1999

In order to analyze the discharge-pumped KrF excimer laser, computer simulation code is developed. On the other hand, the electron velocity distribution in a discharge plasma, measured by the Thomson scattering method, showed the Maxwellian, while the code predicted non-Maxwellian. This disagreement was solved by introducing the electron-electron collision into the simulation code. We also developed a simulation code on the CO2 laser-heated plasma in high-pressure Ar gas, and estimated the formation process of Ar2 excimer. The code predicted the possibility of the Ar2 laser action at 126 nm.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2009년도 춘계학술논문발표회 논문집
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• pp.570-575
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• 2009

본 논문에서는 피난해석에 사용되는 BuildingEXODUS code의 HAZARD에 피난의 환경 조건으로서 화재모사전용 FDS code의 계산결과를 직접 피난의 환경조건으로 생성하는 프로그램 개발 내용을 다루었다. 계산결과의 변환과정에는 수치기법이 적용되었으며, FDS의 Single Block 또는 Multi-Block Meshes에도 적용이 가능하도록 하였다. 본 프로그램의 개발로 피난해석 수행 시 대규모의 화재해석데이터의 입력의 편리성을 높이고, 화재에 대한 피난 해석 과정을 단축하게 되었다.

• 한국추진공학회지
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• 제23권5호
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• pp.67-74
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• 2019

본 논문에서는 개방형 사이클 액체로켓엔진의 시동해석을 위해 개발된 해석 코드의 수학적 모델을 제시하였다. 추진제 공급 배관에서의 추진제 충진 과정을 포함하여 엔진을 구성하는 대부분의 요소를 고려하였다. 한국형발사체 시험발사체에 사용된 75톤급 엔진의 시동해석을 수행하였으며, 해석 결과와 실험 결과가 잘 일치함을 보임으로써 시동해석 코드의 타당성을 증명하였다.

• 한국시뮬레이션학회논문지
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• 제5권1호
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• pp.67-79
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• 1996

This paper proposes an intelligent simulation generator, called INSIMS, for manufacturing systems. The INSIMS provides an interactive dialogue interactive dialogue interface and code generation tools for modeling and code genration of manufacturing systems. The interactive dialogue interface helps non-expert simulation modeler specify manufacturing systems with ease. After completing the model construction processes, the modeling specifications are automatically converted into SLAM II codes by code generation tools. To validate the usefulness of INSIMS and to illustrate the modeling processes, an example system has been presented.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3388-3400
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• 2023

Detailed analysis of the neutron pathway through matter inside the nuclear reactor core is exceedingly needed for safety and economic considerations. Due to the constant development of high-performance computing technologies, neutronics analysis using computer codes became more effective and efficient to perform sophisticated neutronics calculations. In this work, a commercial pressurized water reactor (PWR) presented by Virtual Environment for Reactor Applications (VERA) Core Physics Benchmark are modeled and simulated using a high-fidelity simulation of OpenMC code in terms of criticality and fuel pin power distribution. Various problems have been selected from VERA benchmark ranging from a simple two-dimension (2D) pin cell problem to a complex three dimension (3D) full core problem. The development of the code capabilities for reactor physics methods has been implemented to investigate the accuracy and performance of the OpenMC code against VERA SCALE codes. The results of OpenMC code exhibit excellent agreement with VERA results with maximum Root Mean Square Error (RMSE) values of less than 0.04% and 1.3% for the criticality eigenvalues and pin power distributions, respectively. This demonstrates the successful utilization of the OpenMC code as a simulation tool for a whole core analysis. Further works are undergoing on the accuracy of OpenMC simulations for the impact of different fuel types and burnup levels and the analysis of the transient behavior and coupled thermal hydraulic feedback.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.1966-1973
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• 2023

Virtual reality technology has been widely used in the field of nuclear and radiation safety, dose rate computing in virtual environment is essential for optimizing radiation protection and planning the work in radioactive-controlled area. Because the CPU-based gamma dose rate computing takes up a large amount of time and computing power for voxelization of volumetric radioactive source, it is inefficient and limited in its applied scope. This study is to develop an efficient gamma dose rate computing code and apply into fast virtual simulation. To improve the computing efficiency of the point kernel algorithm in the reference (Li et al., 2020), we design a GPU-based computing framework for taking full advantage of computing power of virtual engine, propose a novel voxelization algorithm of volumetric radioactive source. According to the framework, we develop the GPPK(GPU-based point kernel gamma dose rate computing) code using GPU programming, to realize the fast dose rate computing in virtual world. The test results show that the GPPK code is play and plug for different scenarios of virtual simulation, has a better performance than CPU-based gamma dose rate computing code, especially on the voxelization of three-dimensional (3D) model. The accuracy of dose rates from the proposed method is in the acceptable range.

• 신재생에너지
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• 제7권4호
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• pp.50-57
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• 2011

A wind turbine simulation program for the coupled dynamics of aerodynamics, elasticity, multi-body dynamics and controls of turbine is newly developed by combining an aero-elastic code and a multi-body dynamics code. The aero-elastic code, based on the blade momentum theory and generalized dynamic wake theory, is developed by NREL(National Renewable Energy Laboratory, USA). The multi-body dynamics code is commercial one which is capable of accounting for geometric nonlinearity and twist deflection. A turbulent wind load case is simulated for the NREL 5-MW baseline wind turbine model by the developed program and FAST. As a result, the two results agree well enough to verify the reliability of the developed program.