• Computational Structural Engineering
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• v.3 no.3
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• pp.62-65
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• 1990

RISC System/6000은 유닉스 시스템인 AIX를 오퍼레이팅 시스템으로 채택하였고, 기존의 RISC기술에 혁신적인 진보를 이룩하여 가격 대 성능비를 크게 높임과 동시에 시스템의 기능을 극도로 최적화 시킨 새로운 차원의 아이비엠의 고성능 시스템패밀리이다. 이 시스템은 새로운 RISC 시스템 구조인 POWER(Performance Optimization With Enhanced RISC) 개념과 제2세대 수퍼스칼라 기법 및 마이크로 채널 아키텍쳐로 설계되어 있다. 특히 하나의 사이클에서 4개 이상의 명령어를 병렬처리 하도록 설계된 수퍼스칼라 기능을 통하여 복잡한 그래픽 또는 이미지 처리 및 고도의 수치해석 기능이 뛰어나다. RISC시스템/6000은 과학기술계산업무나 멀티사용자의 일반 비즈니스용으로도 모두 뛰어난 범용 컴퓨터로 그래픽 프로세서의 선택과 함께 CAD/CAM이나 그래픽/애니메이션전용 시스템을 구성할 수 있으며, 최고 512 사용자에 이르는 멀티 사용자 시스템을 구성하여 사용할 수 있다. 이전의 유닉스 시스템에 있어서 큰 약점이었던 사용자 인터페이스와 멀티 사용자 및 테스킹이 크게 강화 되었으며, 기존의 IBM 시스템 및 타 기종과도 네트워크 구성이 용이하고 수백여종의 과학기술 적용업무를 이용할 수 있다.

• International Journal of Highway Engineering
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• v.13 no.1
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• pp.185-195
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• 2011

Aircraft-related accidents cause mass casualties and major material damages. At present, runway-related accidents in our country account for 28% of all air accidents. Furthermore, internationally 33% of all air accidents is connected with runway. To prevent these accidents, FAA mandates the installation of aircraft rapid arresting system(ARAS) at the runway end safety areas which do not meet the FAA requirements. Even if the areas satisfy the conditions, FAA recommends the installation of ARAS to ensure the safety. In accordance of the international affairs, the domestic studies for ARAS are in progress and the legal formalities for domestic adoption of ARAS is under way. In this study, we analyzed the stopping distance, drag force, vertical force and tire penetration of runway overrun to assess the performance of ARAS reasonably by using two different kinds of analysis programs. The first is ARRESTOR program adopted by FAA, and the second is LS-DYNA which is available for 3-dimensional nonlineal dynamic analysis. As a result, analytically the stopping distances between two programs are similar. The drag force is rather different, but the tendencies are similar. Later on, the 3-dimensional simulation analysis considering various air-craft condition and properties of packaging materials is necessary. In addition, ongoing development of simulation analysis program is required for more accurate analistic results.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.2
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• pp.11-21
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• 2005

A three-dimensional parallel Euler flow solver has been developed for the simulation of unsteady rotor-fuselage interaction aerodynamics on unstructured meshes. In order to handle the relative motion between the rotor and the fuselage, the flow field was divided into two zones, a moving zone rotating with the blades and a stationary zone containing the fuselage. A sliding mesh algorithm was developed for the convection of the flow variables across the cutting boundary between the two zones. A quasi-unsteady mesh adaptation technique was adopted to enhance the spatial accuracy of the solution and to better resolve the wake. A low Mach number pre-conditioning method was implemented to relieve the numerical difficulty associated with the low-speed forward flight. Validations were made by simulating the flows around the Georgia Tech configuration and the ROBIN fuselage. It was shown that the present method is efficient and robust for the prediction of complicated unsteady rotor-fuselage aerodynamic interaction phenomena.

• Journal of Korean Society of Steel Construction
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• v.20 no.1
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• pp.151-163
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• 2008

A formulation of three-dimensional model of articulated train-b ridge dynamic interaction has been made for the Korean eXpress Train (KTX). Semi-periodic profiles of rail irregularities consisting of elevation, alignment, cross and gauge irregularities have also been proposed using FRA maximum tolerable rail deviations. The effects of rail joints and sleeper step were also included. The resulting system matrices of train and bridge are very spare, and thus, are stored in one-dimensional arrays, yielding a time-efficient solution. A numerical algorithm for computing bridge-train response including an iterative scheme is also formulated. A program simulating train-bridge interaction and solving this problem using the new algorithm is implemented as new modules for the f inite element analysis software named XFINAS. Computed results using the new program are then checked by that of the validated 2-D bridge-train interaction model. This new 3D analysis provides more detailed train responses such as swaying, bouncing, rolling, pitching and yawing accelerations, which are useful inevaluating passenger riding comfort. Train operation safety and derailment could also be directly investigated by relative wheel displacements computed from this program.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.1
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• pp.55-62
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• 2015

The electromagnetic force induced by an intense electric current pulse, which generates an electromagnetic field around the metal jet originating from a shaped charge, can disperse and scatter the high-speed metal jet. An electric device consisting of an RLC circuit applies an intense electric current pulse that flows in the circuit while the metal jet passes between two electrodes. In this study, the metal jet formation was simulated using the ALE technique in 2-D, and a 3-D finite element model was mapped using 2-D simulation results to induce the electric current directly. The deformed shapes of the metal jet and the electromagnetic force were calculated using a finite element analysis by inducing the electric current directly, and the major parameters of the intense electric current pulse for breaking up the metal jet were examined.

• Journal of the Korean Geotechnical Society
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• v.24 no.8
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• pp.35-41
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• 2008

Laminar-shear-boxes are widely used to simulate free-field seismic ground response by using a l-g shaking table or geo centrifuge in geotechnical earthquake engineering. This study numerically modeled and compared the ground responses in the free field, rigid box, and laminar shear box by using a 3-D FEM program. It is found from the numerical simulations that the laminar shear box can simulate the free field ground movement more precisely than the rigid box. However, the laminar shear box underestimated the surface acceleration of the free field ground. It also showed low-frequency characteristics probably because the stiffness and inertia effect of surrounding ground are neglected.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.15 no.1
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• pp.97-105
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• 1997

In order to conserve architecture accurately as original feature, we need to get the data which is measured in detail about the information of size, position, type, shape, and other terms for architectures. Recently, we need to get data fast and correctly, to compose and to update the database of geographic information system, but using existing method. it is difficult to update the data effectively in the rapid development of information industry. In this study, therefore, It is measured precisely architecture using accurate close-range photogrammetry The aims of this study are real-measured plan by processing acquired image through multi-image matching method if photogrammetry, suggesting the method which is able to draw in detail front plane and plane of well-established architecture, and giving data to obtain accurate size and 3-D coordinate using analytical method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.4
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• pp.204-211
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• 2011

A dynamic analysis procedure is developed to provide a better estimation of the dynamic responses of bridge during the passage of high speed railway vehicles. Particularly, a three dimensional numerical model including the structural interaction between high speed vehicles, bridges and railway endures to analyse accurately and evaluate with in-depth parametric studies for dynamic responses of various bridge span lengths running KTX railway locomotive up to increasing maximum speed(450km/h). Three dimensional frame element is used to model the simply supported pre-stressed concrete (PSC) box bridges for four span lengths(40~25m). Track irregularity employed as a stationary random process from the given spectral density functions and irregularities of both sides of the track are assumed to have high correlation. The high-speed railway vehicle (KTX) is used as 38-degree of freedom system. Three displacements (Vertical, lateral, and longitudinal) as well as three rotational components (Pitching, rolling, and yawing) are considered in the 38-degree of freedom model. The dynamic amplification factors are evaluated by the developed procedure under various traveling conditions, such as track irregularity camber, train speed and ballast. The dynamic analysis such as Newmark-${\beta}$ and Runge-Kutta methods which are able to analyse considering the dynamic impact factors are compared and contrasted.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.141-149
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• 2009

In this paper, quasi-static FDTD method is implemented by FORTRAN programming, and it is used for analysis of body induced current in middle frequencies. The quasi-static FDTD program is validated by comparing the calculation result with analytic solution of the test model, to which it is difficult to apply conventional FDTD. It is confirmed that the time-step is reduced by $5.68{\times}10^6$ times. Using validated numerical technique, body induced current distribution in high resolution 3-D human model is calculated for 20[kHz] magnetic field exposure and 1[MHz] electric field exposure. Also, the effect of grounding condition of both feet on the distribution and amplitude of the induced current is analyzed. It is expected that this research can be applied to various fields including safety assessment of body induced current and development of diagnosis devices using bio-electricity.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.3
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• pp.247-252
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• 2008

Recently, the virtual construction system in which project participants efficiently share and control the information throughout the life-cycle of construction project using 3D object models is being developed all over the world. In this paper, a design of interface between 3D object model of structures and structural analysis system that is essential for the analysis and design of civil structures in the virtual space is treated. The relation parametric modeling technique that is needed to make the 3D object models and the construction method of product breakdown structure(PBS) that considers the several parameters for the structural analysis are presented. PBS is built so that it is possible to extract needed attribute information from 3D object model and to apply it to the structural analysis. Design methodology for interface program is proposed that several numerical values determined by the cooperative work same as structural analysis are delivered to 3D object models without additional work. An interface program between 3D object models and structural analysis system developed based on the proposed method would be effectively used to develop virtual construction system.