• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.53-56
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• 2007

Computer simulation of microstructure evolution during hot forging process is of great interest in recent years. Recrystallization model and grain growth model which use a phenomenological approach were summarized. For the waspaloy, upsetting process and cogging process were simulated using $DEFORM^{TM}$ and the change in grain size were investigated in each deformation procedure.

• 한국시스템다이내믹스연구
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• 제3권1호
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• pp.5-42
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• 2002

The main purpose of this paper is analyzing long-term growth possibility of a telecommunication Company (Telco) H. First of all, to achieve this purpose, the precise understanding about causal relations among growth and decay factors of Telco H is required. Based upon the causal analysis, a basic computer simulation model is developed. Finally, several predictive examinations about growth possibility and pattern of the Telco H are conducted using three scenarios. From simulation results, the most important policy leverages are capabilities of market share sustenance, improvement of service quality and squeezing current network facility to elevate profitability and efficiency. Recently, telecommunication industry has become more and more competitive due to introduction of Internet and deregulation. Internet has brought about global competition as well as confusion between telecommunication and broadcasting industries. At the almost same time, deregulation is a universal tendency and a catalyst of unlimited competition. Telco H has been a dominant company in Korea for last century. However, the dominant position of Telco H has been threatened by the change of competition environment. The competitive environment has many elements and keeps changing dynamically. Therefore, System Dynamics simulation methodology is adopted to examine the problem.

• 한국시스템다이내믹스연구
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• 제17권2호
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• pp.5-32
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• 2016

Purpose of this paper is to review series of Limits to Growth studies from its original Rome Club Report published in 1972 to the most recent one in 2012 by Jorgen Randers and finds its implications on concept and strategy of sustainable development. For this purpose first, this paper reviewed series of Limits to Growth studies in details with focus on scenarios used in simulation of world model. Second, response to the original Limit to Growth was reviewed and to see validity of its scenario based simulations, simulated results of interest variables and actual historical data up to the year 2010 was compared. Third, structure and key arguments in both studies, Limit to Growth studies and Our Common Future was explained and compared. Finally, implications of the Limit to Growth studies on concept and strategy for sustainable development was discussed. Based on the comparison, this paper argued that even if the term sustainable development was not used in the Limit to Growth at all, concept and strategies for sustainable development implied in the Limit to Growth are more clear and specific than those of Our Common Future. Since Limit to Growth studies were simulation based ones that produce detailed behaviors on interest variables, it clarifies more clearly the abstract concept of sustainable development and thus, provides specific guidelines for the direction of sustainable policy which has been suffering long from vagueness of concept of sustainable development.

• ETRI Journal
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• 제36권3호
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• pp.450-459
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• 2014

In this paper, we present a new, easy-to-generate system that is capable of creating virtual 3D tree models and simulating a variety of growth processes of a tree from a single, real tree image. We not only construct various tree models with the same trunk through our proposed digital image matting method and skeleton-based abstraction of branches, but we also animate the visual growth of the constructed 3D tree model through usage of the branch age information combined with a scaling factor. To control the simulation of a tree growth process, we consider tree-growing attributes, such as branching orders, branch width, tree size, and branch self-bending effect, at the same time. Other invisible branches and leaves are automatically attached to the tree by employing parametric branch libraries under the conventional procedural assumption of structure having a local self-similarity. Simulations with a real image confirm that our system makes it possible to achieve realistic tree models and growth processes with ease.

• Journal of Korean Vacuum Science & Technology
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• 제6권1호
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• pp.22-29
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• 2002

The process of energetic deposition has been simulated by using molecular dynamics (W) simulation and kinetic Monte Carlo (KMC) simulation. The atomistic mechanisms of film growth in energetic deposition are discussed.

• 한국결정성장학회지
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• 제16권1호
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• pp.38-42
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• 2006

본 1부 연구에서는 스파크 플라스마 열에 의한 그린 세라믹의 소결에서 열전달 및 가압력으로 인한 상대밀도의 변화를 유한요소법(FEM)으로 해석하고 그 결과에 따른 입자성장을 몬테카를로법(MCM)을 이용하여 전산모사하는 방법을 제시하기 위하여 SPS의 FEH 해석과 MCM 해석의 이론적 배경을 기술한다.

• 한국식품영양과학회지
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• 제26권4호
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• pp.704-713
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• 1997

Simulation의 결과와 PAF식으로 계산된 성장기의 단백질 축적량과의 상대적 차이는 8.8%를 보여 본 연구의 타당성이 확인되었다. 성장률을 나타내는 총 체단백질량에 대한 단백질 축적량은 양질의 단백질을 섭취 할 경우 성장함에 따라 parabolic 형태를 띄나, 사료단백질의 질이 낮아짐에 따라 150일 simulation 기간내에 이러한 형태는 사라졌다. 성장하는 동안 단백질 회전의 두요소가 항상 병행하여 증가하였다 단백질 합성량과 분해량은 서로 병행하여 단백질 질에 따라 차이를 보였는데, 질이 높은 단백질을 섭취하였을 때 단백질 축적의 증가는 높은 단백질 합성량과 분해량에 의해 일어남 을 보여 주었다. 이는 근육단백질의 대사형태(5)를 반영하며, 그리하여 돼지의 총 단백질대사는 근육단백질에 의해 결정됨을 확인해 주었다. 그리고 단백질 질이 낮을 경우 매일의 단백질 대사율과 성장률이 저하할 뿐 아니라 성장지연도 일어남을 보여 주었다 본 연구에서 추정된 필수아미노산의 총 필요량은 28.1g이며, 일반적으로 돼지 사료의 제1 제한 아미노산인 lysine의 필요량은 4.2g이다. 이러한 아미노산 필요량은 NRC에서 권장하는 균형잡힌 아미노산 조성과 유사하다. 이와 같이 본 연구는 동위원소를 사용한 실험을 시행할 필요없이 simulation을 통해 다양한 질의 사료단백질에 따른 단백질 축적량에 대한 자료만으로 성장기의 단백질 회전률과 단백질대사의 동적행위를 나타내어 식이의 단백질 질의 변화에 적응하는 기전을 나타낼 수 있음을 보여주었다.

• 대한화학회지
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• 제56권4호
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• pp.431-439
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• 2012

Dissipative particle dynamics (DPD) was carried out to study the nucleation and crystal growth process of $CeO_2$ nanoparticles in different alcohol aqueous solutions. The results showed that the nucleation and crystal growth process of $CeO_2$ can be classified into three stages: nuclei growth, crystal stabilization and crystal aggregation except the initial induction stage, which could be reproduced by collecting simulation results after different simulation time. Properly selecting the sizes of $CeO_2$ and water bead was crucial in the simulation system. The influence of alcohol type and content in solutions, and precipitation temperature on the particle dimension were investigated in detail and compared with the experimental results. The consistency between simulation results and experimental data verify that the simulation can reproduce the macroscopic particle aggregation process. The effect of solvent on the nucleation and crystal growth of $CeO_2$ nanoparticles are different at three stages and can not be simply described by Derjaguin-Landau-Verwey-Overbeek (DLVO) theory or nucleation thermodynamics theory. Our work demonstrated that DPD methods can be applied to study nanoparticle forming process.

• 한국결정성장학회지
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• 제1권1호
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• pp.74-81
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• 1991

Czochralski 단결정 성장계에서 유체동의 표면 복사열전달을 고려하여 온도분포를 모사하였다. 복사열전달 고려시 표면요소들의 view factor를 고려하였다. 고-액의 2상은 고상에 가상적으로 매우 큰 점성을 부여하여 연속의 단상으로 처리하였으며 응고시 잠열은 반복열량 방출법을 개발하여 처리하였다. 본 연구에서 개발한 응고 모델을 증명하기 위하여 Ca 금속의 용융에 적용하여 실험결과와 비교한 결과 잘 맞는다는 것을 알아낸 후 본 모사 프로그램을 Cz계에서 Al금속의 단결정 성장에 적용하였다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 춘계학술대회 논문집
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• pp.40-45
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• 2000

Presented are the estimation of the probability distribution of fatigue crack growth life and reliability assessment of structures by simulating material resistance to fatigue crack growth along a crack path. The material resistance is treated as a Weibull stochastic process. A non-Gaussian stochastic fields simulation method proposed by Shimozuka, et al is applied with the statistical data obtained experimentally. Test results are obtained for $\Delta$K constant amplitude load in tension with stress ratio of R=0.2 and three specimen thicknesses of 6, 12 and 18mm. This simulation method is useful to estimate the probability distribution of fatigue crack growth life and the smallest life.