• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.6
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• pp.517-525
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• 2011

Differential Vibrating Accelerometer(DVA) is a small and accurate resonant device to sense the change in natural frequency in presence of acceleration input. Both mathematical modeling for the electromechanical dynamics and experimental investigation on the structural characteristics are necessary for effective designs of precision controller and high Q-factor structure. In this paper, electromechanical modeling of the resonator of DVA, electrode module, and pre-amplifier is presented. The presented method is experimentally verified by measuring the resonance frequency, effective mass, effective stiffness and Q-factor. The direct comparison of the calculated displacement and the actual pre-amplifier of DVA also indicates the effectiveness of this study.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06c
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• pp.382-384
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• 2012

뉴럴 네트워크 구조를 이용하여 새로운 햅틱 질감 모델링 방법을 제시하고, 실제 측정한 데이터를 이용해 이 방법을 검증하였다. 제시된 방법은 높은 주파수의 가속도 성분까지 성공적으로 모델링 하기 위해서 여러 개의 뉴럴 네트워크를 병렬적으로 이용하여 구현되었으며, 기존 방법에 비해서 새로운 물체의 질감을 모델링 하기가 간편하였다. 실제로 측정한 데이터로 교차 검증을 실시한 결과 물체의 표면에서 생성되는 가속도를 약 75 %의 correlation으로 재생하는 결과를 얻을 수 있었다.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.624-630
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• 2006

This paper studies a modeling to demonstrate predicted reliability of the train control system components by performing an accelerated stress test. There are two tests for demonstrating predicted reliability; test run at the whole system level, and accelerated life test and accelerated stress test at the component level. In this paper, we imposed accelerated stress on the system and studied the train control system modeling for the accelerated stress test, which demonstrates predicted reliability according to whether or not the equipment is operating. Reliability of train control system consisting of electronic components varies drastically according to temperature so we considered the Arrhenius equation and the activation energy of electronic components. We also used reliability modeling with weighted average and calculated time necessary to complete the accelerated stress test on train control system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.2
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• pp.75-83
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• 2005

NASA/DLR Gravity Recovery and Climate Experiment (GRACE) mission, which consists of two co-orbiting low altitude satellites, is to measure the Earth gravity field with unprecedented accuracy. Its key instruments include inter-satellite ranging systems and three-axis accelerometers. For the preliminary design and requirements analysis, extensive instrument simulation models are developed. These modeling techniques and orbit-gravity field estimation techniques are described.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.29-32
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• 2004

In this study, we had modelled Siemens type MLC using BEAM Monte Carlo code and tested the feasibility of the modelling. To model the Primus linac MLC, we had measured the actual dimensions of MLC and each leaves, then approximated the leaf shape. VARMLC component module was used for the modelling and leakage, tongue-and-groove effect were also considered. Simulation result showed the good agreement with the film measurement.

• Journal of the Korean Geotechnical Society
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• v.34 no.8
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• pp.15-26
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• 2018

Recently, as the seismic performance based design methods have been introduced, dynamic numerical analyses need to be performed to evaluate the actual performance of structures under earthquakes. The verification of the numerical modeling is the most important for the performance based design. Therefore, 2-dimensional numerical analyses were performed to simulate the seismic behavior of a pile-supported structure, to provide the proper numerical modeling and to determine of input parameters. A dynamic centrifuge test of a pile group in dry loose sand was simulated to verify the applicability of the numerical model. The numerical modeling was carefully made to reflect the actual condition of the centrifuge test including dynamic soil properties, soil-pile interaction, boundary condition, the modeling of the group pile and structure and so on. The predicted behavior of the numerical analyses successfully simulated the acceleration variation in ground, the moment and displacement of the pile, and the displacement and acceleration of the structure. Therefore, the adopted numerical modeling and the input parameters can be used to evaluate the seismic performance of pile groups.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.336-338
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• 2023

Sparse한 데이터가 딥러닝에 자주 사용됨에 따라 다양한 sparse 텐서 가속기들이 연구되고 있다. 하지만 이런 sparse 텐서 가속기들은 특수 하드웨어 모듈을 채용하고 있고, 다양한 구조로 되어 있다. 또한, 가속기들의 효율성이 데이터의 sparsity에 따라 달라지기 때문에 서로의 직접적인 비교도 힘들다. 따라서 이 문제들을 해결하기 위해, sparse 텐서 가속기들을 모델링하여 서로를 비교하려는 연구들이 존재하며, 이 논문에서는 이에 관한 연구 동향을 서술하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.254-260
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• 1995

본 연구에서는 제어 알고리듬 적용면에서 가속도 계측이 보다 용이한 점을 고려하여 가속도가 포함된 가속도-속도-변위 되먹임 제어 알고리듬을 개발하고, 이를 유압식 능동 질량구동장치에 적용하여 능동제어시스템의 성능을 실증적으로 검토한다. 이 때 능동제어시스템의 구성요소들의 동특성을 시스템 모델링에 포함하여 제어력을 산정함으로써 시간 지연의 영향을 효과적으로 보상하는 방안을 제시한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.10a
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• pp.215-216
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• 2009

By growing the capacity of container in the world, main container terminal in countries introduces the automated container equipments and try to improve the productivity for handling the container. ARMC(Automated Rail Mounted Crane) is installed in automated container terminal and expected the high efficiency of productivity by using minimum-time control method. However recently by the GREEN Port policy, high energy efficiency method for container equipments is importance issue in ports. In this paper, the 3-dimensional modelling of AMRC is discussed and the acceleration characteristics for ARMC is analyzed By using the results of this paper, the advanced controller for the crane will be developed in future.

• Journal of the Korean Vacuum Society
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• v.2 no.3
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• pp.282-287
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• 1993

PLS 2GeV 선형가속기 진공계는 K6 가속단위까지 성공적으로 조립, 설치되어 있다. K3 가속단위까지는 이미 E3712형 클라이스트론에서 공급되는 70MW 극초단파 전력으로 진공계 길들이기 과정을 완료하였다. 약 50MW의 극초단파 전력을 인가한 상태에서, 현재 진공도는 L-형 가속관 중심에서 6.2$\times$10-8torr, 클라이스트론 출력창에서 7.3$\times$10-9torr를 각각 유지하고 있으며, 최종 도달압력은 점차적으로 향상되고 있는 중이다. 본 논문에서는 PLS 2 GeV 선형가속기 진공계에 대한 전기회로적 변환에 의한 모델링과 해석, 그리고 가속기 전반부에 관한 초기 성능 검증결과를 논의하고자 한다.