• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1992.08a
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• pp.146-149
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• 1992

The dynamic inelastic analysis is now often performed for the safe structural design against the seismic events or explosions. Several powerful methods of dynamic inelastic analysis such as direct intergration methods and modal superposition methods were developed with the development of computers during the last three decades. This type of analysis generally adopts the step-by-step time-integration procedure and gives a complete time history of the evolution of the structure.(omitted)

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.94-97
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• 1987

An acousto optic correlator system for performing real-time correlation of two signals is constructed. It uses AOD is described. The statistical analysis for correlator's output SNR is presented and experimental procedure for implemention of this technique are result shown. Since the correlation intergration is performed in time rather than space, the SNR of this system can be greatly improved.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.165-169
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• 2000

A Development on integration of Railroad System and Production of Proto multiple type vehicle, which can run without change of vehicle or Bogie under running conditions of every countries, are needed for the transportation between. Asia and Europe. An integration of Railroad System will benefit not only the transportation costs but also the time drastically, which is very meaningful for the modern international trading.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.143-153
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• 1998

In this reaserch, a program for real time simulation of a vehicle is developed. This program uses relative coordinates to save the computation time and BDF(Backward Difference Formula) to integrate system variables. Numerical tests were performed for J-turn and Lane change steering, respectively. The validity of the program is proved by the ADAMS package. Numerical results showed that the proposed implicit method is more stable in carrying out the numerical integration for vehicle dynamics than the explicit method. Hardware requirements for real time simulation are suggested.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.5
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• pp.360-369
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• 1986

An AO TIC system for performing real-time correlation of two signals is constructed. It uses AOD(Acoustooptic Device) and CCD(Charge Coupled Device). An acoustooptic technique for achieving signal correlation isdescribed. The statistical analysis for correlator's output SNR is presented and experimental procedure for implemention of this technique are result shown. Since the correlation intergration is performed in time rather thatn space, the SNR of this system can be greatly improved.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.5
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• pp.1134-1143
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• 1994

A study of adiabatic shear band formation and propagation of 4340 steel was done using the stepped speciment which was subjected to high velocity impact. The high velocity impact was performed on compression Hopkinson bar impact machine. After the controlled impact, the specimen was prepared for visual inspection. Numerical simulation was also performed with same geometrical dimension using explicit time integration finite element code. Experimental results were then compared with the numerical prediction. It was found that the numerical prediction is quite accurate, average thickness of adiabatic shear band is about $10{\mu}m$, the macro crack around shoulder is due to folding, and the deformation control ring is effective to freeze the propagation of adiabatic shear band.

• Journal of KSNVE
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• v.10 no.3
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• pp.531-535
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• 2000

A three-parameter model of viscoelastic damper which has a non-linear spring as an element is incorporated into an oscillator. The behavior of the damper model shows non-linear hysteresis curves which is qualitatively similar to those of real viscoelastic materials. The motion is governed by get analytic solutions of the system. The frequency-response curves show that multiple solutions co-exist and that the jump phenomena can occur. In addition it is shown that separate solution branch exists and that it can merge with the primary response curve. Saddle-node bifurcation sets explain the occurences of such non-linear phenomena. A direct time intergration of the original equation of motion validifies the use of the harmonic balance method to this sort of problem.

• Journal of the Korean Institute of Educational Facilities
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• v.2 no.2
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• pp.51-64
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• 1995

This study investigates possible of linkage between kindergarten infants and the lower level elementary school students so aims to take a triangular position which direction of architectural space plan. The results of the study are as follows: 1) The results of analysis which infants and lower level elementary school students' behavior and activity showed similar play patterns in space attitude, rule of space use, similar to satisfaction and kinds of play, the time required, groups scale and place of play. 2) Architectures of kindergarten and lower level elementary school can classify style of selfhelp-singleness, establishment as an annex-singleness, establishment as an annex-attachment and divides space of education, management, service and analogized kinds of necessary space. 3) Infants of four, five years old and six, seven years old(first, second elementary school students) are similar to physical, intellectual, emotional development and have special characters of successions so kindergarten and lower level elementary school buildings must be necessary for organic linkage and intergration.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.3
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• pp.32-41
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• 1995

In the analysis of metal forming processes by the finite element method, there are many numerical instabilities such as element locking, hourglass mode and shear locking. These instabilities may have a bad effect upon accuracy and convergence. The present work is concerned with improvement of stability and efficiency in two-dimensional rigid-plastic finite element method using various type of elemenmts and numerical intergration schemes. As metal forming examples, upsetting and backward extrusion are taken for comparison among the methods: various element types and numerical integration schemes. Comparison is made in terms of stability and efficiency in element behavior and computational efficiency and a new scheme of adaptive directional reduced integration is introduced. As a result, the finite element computation has been stabilized from the viewpoint of computational time, convergency, and numerical instability.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.112-114
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• 2003

현재 네트워크 시스템 구조는 고정된 호스트에게 실시간 서비스를 제공할 수 있지만, MH(Mobile Host)가 빈번하게 이동하는 이동 컴퓨팅 환경에는 높은 수준의 QoS(Quality of Service)를 제공하지 못한다. 이러한 문제를 해결하기 위해 본 논문은 Mobile IP와 Cellular IP 통할 환경에서 MH의 핸도오프를 내부영역 핸드오프(intra­domain handoff)와 외부영역 핸드오프(inter­domain handoff)로 나누어 실시간 서비스를 제공하기 위한 자원 예약 기법을 제안한다. 이 예약 기법은 MH의 이동에 관계없이 높은 수준의 QoS를 제공할 수 있고, Mobile IP 네트워크 영역의 부하를 줄일 수 있는 장점이 있다.