• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제37회 하계학술대회 초록집
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• pp.247-247
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• 2009

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1986년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 17-18 Oct. 1986
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• pp.326-330
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• 1986

Some of computational algorithms for the kinematic control of redundant manipulators are investigated and analyzed by extensive computer simulations.

• 한국컴퓨터그래픽스학회논문지
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• 제14권4호
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• pp.35-39
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• 2008

협업 시스템은 원거리의 다수 사용자들이 시간과 공간의 제약을 받지 않고 공동의 작업을 진행 할 수 있도록 서비스를 제공하는 시스템이다. 하지만 모든 시스템들이 그렇듯이 처음 사용할 때는 여러 가지 시행작오가 생기게 된다. 가상분자모델링 시스템인 VRMMS[1]는 여러 사용자들이 온라인상에서 분자 구조를 관찰하고 시뮬레이션 결과를 확인 할 수 있고 또한 피드백까지 줄 수 있는 협업시스템인데, 분자 모델을 연구하는 사람들에게는 유용한 시스템이지만 익숙하게 분자 구조를 조작하기 위해서는 인터페이스에 대한 학습이 필요하다. 가장 좋은 방법은 직접 만나서 교육을 시켜주는 것이지만 한 장소가 아닌 여러 장소에서 원격으로 실험을 진행하는 상황에서는 사용법에 대한 직접적인 교육이 힘들기 때문에 시행착오 기간이 길어질 수 있다. 본 논문에서는 이러한 시행착오를 줄이기 위해 가상의 현실세계인 세컨드라이프[2]를 통해 분자 구조를 관찰하고 시뮬레이션을 할 수 있는 협업시스템을 제안한다. 각각의 사용자들은 가상세계에서 자신의 아바타를 통해 가상분자모델링 시스템인 VRMMS를 사용하여 현실 세계에서와 같은 방식으로 실험을 진행할 수 있으며, 실험에 익숙하지 않는 사용자들은 실험방법을 직접 보고 따라 해 볼 수 있어서 좋은 학습효과를 기대할 수 있다.

• 천문학회지
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• 제38권2호
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• pp.165-168
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• 2005

We overview the GRAPE (GRAvity piPE) project. The goal of the GRAPE project is to accelerate the astrophysical N-body simulations. Since almost all computing time is spent for the evaluation of the gravitational force between particles, we can greatly accelerate many N-body simulations by developing a specialized hardware for the force calculation. In 1989, the first such hardware, GRAPE-1, was completed, with the peak speed of 120 Mflops. In 2003, GRAPE-6 was completed, with the peak speed of 64 Tflops, which is nearly 106 times faster than GRAPE-l and was the fastest computer at that time. In this paper, we review the basic concept of the GRAPE hardwares, the history of the GRAPE project, and two ongoing projects, GRAPE-DR and Project Milkyway.

• Journal of Mechanical Science and Technology
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• 제16권10호
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• pp.1314-1319
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• 2002

A mathematical model and control laws for an Electronic-Vacuum Booster (EVB) for application to vehicle cruise control will be presented. Also this paper includes performance test result of EVB and vehicle cruise control experiments. The pressure difference between the vacuum chamber and the apply chamber is controlled by a PWM-solenoid-valve. Since the pressure at the vacuum chamber is identical to that of the engine intake manifold, the output of the electronic-vacuum booster Is sensitive to engine speed. The performance characteristics of the electronic-vacuum booster have been investigated via computer simulations and vehicle tests. The mathematical model of the electronic-vacuum booster developed in this study and a two-state dynamic engine model have been used in the simulations. It has been shown by simulations and vehicle tests that the EVB-cruise control system can provide a vehicle with good distance control performance in both high speed and low speed stop and go driving situations.

• 천문학회지
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• 제29권spc1호
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• pp.201-204
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• 1996

Magnetic fields are thought to playa role in a wide variety of important astrophysical processes, from angular momentum transport and jet formation in accretion disks to corona formation in stars. Unfortunately, the dynamics of magnetic fields in astrophysical plasmas are extremely complicated, and the success of current theoretical models and computer simulations seems to be inversely correlated with the amount of observational detail available to us. Here I will discuss some of the more striking conflicts between numerical simulations and observations, and present an explanation for them based on an important dynamical process which is not adequately modeled in current numerical simulations. These processes will lead to the formation of flux tubes in stars and accretion disks, in accordance with observations. I will discuss some of the implications of flux tube formation for stellar and accretion disk dynamos.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.252-257
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• 2001

With the help of newly arrived technology such as PC clustering, molecular dynamics (MD) seems to be promising for large-scale materials simulations. A cost-effective cluster is set up using commodity PCs connected over Ethernet with fast switching devices and free software Linux. Executing MD simulations in the parallel sessions makes it possible to carry out large-scale materials simulations at acceptable computation time and costs. In this study, the MD computer code for fracture simulation is modified to comply with MPI (Message Passing Interface) specification, and runs on the PC cluster in parallel mode flawlessly. It is noted that PC clusters can provide a rather inexpensive high-performance computing environment comparing to supercomputers, if properly arranged.

• International Journal of Fluid Machinery and Systems
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• 제8권4호
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• pp.240-253
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• 2015

The objective of this paper is to evaluate the applicability of mass transfer cavitation models and determine appropriate numerical parameters for cavitating flow simulations. CFD simulations were performed for a NACA66 hydrofoil at cavitation numbers of 1.49 and 1.00, corresponding to steady sheet and unsteady sheet/cloud cavitating regimes using the Kubota and Merkle cavitation models. The Merkle model was implemented into CFX by User Fortran code. The Merkle cavitation model is found to give some improvements for cavitating flow simulation results for these cases. Turbulence modeling is also found to have an important contribution to the prediction quality of the simulations. The relationship between the turbulence viscosity modification, in order to take into account the local compressibility at the vapor/liquid interfaces, and the predicted numerical results is clarified. The limitations of current cavitating flow simulation techniques are discussed throughout the paper.

• Nuclear Engineering and Technology
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• 제36권3호
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• pp.276-284
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• 2004

This paper presents the results of the TEXAS-V computer code simulations of FARO L-14, L-28, and L-33. The old break-up model and new break-up model are tested to compare the respective simulations of each. As these experimental data sets cover a wide range of ambient pressures, sub-cooling of the water pool, and the melt jet diameters, the results of the simulations will be beneficial in assessing the TEXAS-V code's capability to predict the steam explosion phenomena in a prototypical reactor case. The current model was found to have some deficiencies, and the modules for the fragmentation, the equation of state, and the interfacial area for each flow regime in TEXAS-V were improved for the simulation of FARO L28 and FARO L-33.

• 반도체디스플레이기술학회지
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• 제10권4호
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• pp.47-51
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• 2011

We investigated the substrate surface polishing by the spherical rigid abrasive under the compression using classical molecular dynamics modeling. We performed three-dimensional molecular dynamic simulations using the Morse potential functions for the various slide-to-roll ratios, from 0 to 1, and then, the compressive forces acting on the spherical rigid abrasive were calculated as functions of the time and the slide-to-roll ratio. The friction coefficients obtained from the classical molecular dynamics simulations were compared to those obtained from the experiments; and found that the molecular dynamic simulation results with the slide-to-roll ratio of 0 value were in good agreement with the experimental results.