• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.1
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• pp.91-104
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• 2008

In tunnels, safety factor concept has been suggested to estimate their stability quantitatively. It is merely limited in the framework of mechanical analysis. However safety factor concept has not been applied in hydro-mechanical coupled analyses due to their modelling complexity. Recently studies on this topic are being actively made. In this study, induced drainage modelling methods for hydro-mechanical coupled analyses are compared and analyzed to estimate safety factor of a subsea tunnel exactly. To this end, methods both controlling hydraulic characteristic of shotcrete and using a drainage well are considered. Sensitivity analysis were carried out on rock class, thickness of shotcrete, and hydraulic properties of rock mass. As the results of this study, it turned out that the induced drainage modelling using a drainage well would give more reliable results than that of controlling hydraulic characteristic of shotcrete in estimating tunnel stability in hydro-mechanical coupled analyses.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.2
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• pp.131-136
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• 2023

Nanocomposites have been considered innovative composite materials that have multi-functionality and high performance. Because the incorporation of nanoscale fillers may significantly improve the electrical, mechanical, and thermal properties of composites, numerous extensive studies on the characterization of nanocomposites with nanoscale fillers have been performed. In particular, the development of nanocomposites using carbon-based nanoscale fillers (e.g., carbon nanotubes, carbon black, graphene nanoplates) have attracted much interest in the composite field. This paper provides a review of recent advances in the electrical/mechanical characteristics of nanocomposites, which are essential for their practical applications. Furthermore, this paper revisits the recent research on multi-scale modeling, which is a promising approach for predicting the characteristics of nanocomposites. The current challenges and future development potentials for multi-scale modeling are also discussed.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.171-174
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• 2004

본 논문은 Hspice 를 사용한 달팽이관 생역학의 능동적이며 선형적인 1 차 그리고 2 차원 모델링을 보여준다. Hspice 모델링의 장점은 달팽이관 생역학을 아날로그 IC 칩으로 구현할 수 있다는 점이다. 즉 Biochip 으로 설계하는데 활용된다. 본 논문은 달팽이관 생역학을 어떻게 전기회로 모델화한 뒤, 다시 어떻게 Hspice 코드로 표현하는 가를 보여준다. 달팽이관 회로가 Hspice 코드 실행을 위해 변형되어야만 하는 과정을 상세히 보여준다. 1 차원의 결과와 2 차원의 결과를 비교하고 있다.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2009.05a
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• pp.157-160
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• 2009

자동차는 지난 한 세기의 짧은 역사를 가지고 현재에 이르기까지 급속한 발전을 이루어왔다. 초기의 기능은 단순히 운송수단과 부의 상징이었지만 최근에는 소비자의 감성과 문화적인 흐름을 반영하는 모습이다. 그리하여 소비자의 감성 분석이 자동차 내장의 가장 중요한 부분으로 여기게 되었다. 자동차에 대한 새로운 감성요구를 실현하기 위해서는 인체와 오랜 시간 접촉해 있는 시트 표피재의 분석이 반드시 필요하다. 본 연구에서는 자동차 시트 표피재의 역학적 특성과 감성을 고려한 고급감을 예측하여 고감성 내장 표피재 개발에 기여하고자 한다. 감성용어는 Softness(유연한), Elasticity(탱글탱글한), Volume(풍성한), Stickiness(끈끈한)를 설정하였으며, 이와 대응하는 표피재의 역학적 특성 치를 측정하였다. 감성 평가에서는 현재까지 알려진 가장 확실하고 재현성 있는 측정법인 일대일 비교법을 통해 고급감에 대해 평가하였다. 이를 통하여 역학적 특성 치와 인간의 감성 평가 치와의 회귀 분석을 실시하여 평가 예측을 가능케 하였다. 즉, 자동차 표피재 중 피혁의 4 가지 물리량으로 인간의 감성인 표피재의 고급감을 예측하여 고감성 자동차 시트 표피재의 개발을 위한 평가 모델링을 구축하였다.

• Explosives and Blasting
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• v.34 no.2
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• pp.31-38
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• 2016

The hydrodynamics code is a numerical tool developed for modeling high velocity impacts where the materials are assumed to behave like fluids. The hydrodynamics code is widely used for solving impact problems, such as rock blasting using explosives. For a realistic simulation of rock blasting, it is necessary to model explosives numerically so that the interaction problem between rock and explosives can be solved in a fully coupled manner. The equation of state of explosives, which describes the state of the material under given physical conditions, should be established. In this paper, we introduced the hydrodynamics code used for explosion process modeling, the equation of state of explosives, and the determination of associated parameters.

• KIISE Transactions on Computing Practices
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• v.20 no.10
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• pp.534-542
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• 2014

Multiscale modeling is a new simulation approach which can manage different spatial and temporal scales of system. In this study, as part of multiscale modeling research, we propose the way of combining two different simulation methods, molecular dynamics(MD) and stochastic rotation dynamics(SRD). Our conceptual implementations are based on LAMMPS, one of the well-known molecular dynamics programs. Our prototype of multiscale modeling follows the form of the third party implementation of LAMMPS. It added MD to SRD in order to simulate the boundary area of the simulation box. Because it is important to guarantee the seamless simulation, we also designed the overlap zones and communication zones. The preliminary experimental results showed that our proposed scheme is properly worked out and the execution time is also reduced.

• Journal of Korea Foundry Society
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• v.41 no.5
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• pp.445-453
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• 2021

Computational thermodynamics for various alloy systems is well known as the CALPHAD technique. Gibbs energy model parameters for each phase are obtained from experimentally measured thermodynamic properties and are mainly used to predict areas not experimentally measured and to analyze experimental results thermodynamically. In this study, the thermodynamic modeling of the Ni-Cr-Nb-C quaternary system is conducted for a thermodynamic analysis of the phenomena by which heat-resistant cast alloys (IN-657) are destroyed in certain areas after long-term use. The stable phases in the system according to the Cr content, phase fraction depending on the temperature, and long-range ordering parameters for the Ni₂Cr phase are calculated and compared to results obtained experimentally. The calculated thermodynamic properties suitably explain the experimentally reported fracture temperature range and the results of stable phases formed in the fractured areas. Thermodynamic modeling through the CALPHD method is expected to be useful for analyzing and predicting the thermodynamic behaviors of various cast alloys.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2002.03a
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• pp.9-18
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• 2002

• 순환기질환의공학회:학술대회논문집
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• 2004.11a
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• pp.48-49
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• 2004

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.200-203
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• 2012

슈퍼 컴퓨터 시스템의 가용 계산 자원이 증가하면서 시뮬레이션 대상의 길이와 시뮬레이션 시간의 스케일을 확장할 수 있는 멀티스케일 모델링에 대한 관심이 높아지고 있다. 본 논문에서는 분자동역학과 전산 유체 역학을 결합하는 멀티스케일 모델링을 대상으로 두 분야의 대표적인 시뮬레이션 소프트웨어를 하나로 조합한 프로토타입의 개발 과정과 고려 사항을 소개한다.