• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.7
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• pp.1058-1064
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• 2003

Noise estimating procedures of oil lubricated journal bearings are presented. Nonlinear analysis of rotor-bearing system including unbalance mass of the rotor is performed in order to obtain acoustical properties of the bearing. Acoustical properties of the bearing are investigated through frequency analysis of the pressure fluctuation of the fluid film calculated from the nonlinear analysis. Noise estimating procedures presented in this paper could aid in the evaluation and understanding of acoustical properties of oil lubricated journal bearings.

• Computational Structural Engineering
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• v.3 no.4
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• pp.10-13
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• 1990

구조물의 동적계수 추정방법과 이에 관련된 몇가지 사항들에 대해서 기술하였다. 여러 문제들중 가장 중요한 것이라고 생각되는 것으 소음에 대한 처리문제라고 여겨진다. 순차적 예측오차법과 같은 비선형 최적화기법을 사용하여 측정오차와 관련된 소음영향은 어느정도 처리되어질 수 있다고 생각되나, 많은 자유도를 가진 실제구조물의 거동을 간단한 모형식으로 나타냄으로써 야기되는 모형화 오차에 대해서는 아직 그 처리방법에 상당한 난점이 있다. 앞으로 이에 대한 많은 연구가 요구되는 실정이다.

• KCID journal
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• v.4 no.1
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• pp.22-33
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• 1997

Seadike construction in order to develope the tidal land is used to significantly affect the water circulation system not only resulting in changes of coastal geometry but causing environmental problems. Therefore it is necessary that resultant effects of

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.160-163
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• 1996

This paper deals with MCMBPC(Multivariable Constrained Model Based Predictive Controller) for nonlinear boiler system with noise and disturbance. MCMBPC is designed by linear state space model obtained from some operating point of nonlinear boiler system and Kalman filter is used to estimate the state with noise and disturbance. The solution of optimization of the cost function constrained on input and/or output variables is achieved using quadratic programming, viz. singular value decomposition (SVD). The controller designed is shown to have excellent tracking performance via simulation applied to nonlinear dynamic drum boiler turbine model for 16OMW unit.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.04a
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• pp.134-147
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• 1994

고차근사가 혼돈응답에 미치는 영향을 조사하기 위하여 비선형문제의 전형인 탄성진자계를 집중적으로 조사하였다. 조화가진력을 가진 탄성진자계는 비자율계(원래계)로 나타나는데 다중시간법을 사용하여 이 계를 이차근사에 의한 자율계 (근사화계)로 변환하였다. 점근해의 초기조건에 대한 민감도의 척도인 Lyapunov 지수를 통하여 비교해 본 결과, 이차근사에 의한 근사화계가 일차근사에 의한 근사화계보다 원래계를 더 잘 반영하고 있음을 확인하였다. 이로써 고차근사가 정상상태 주기응답 뿐만 아니라 혼돈응답을 더 정확하게 예측하는 데도 유용함을 알 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.490-495
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• 1992

A neural model predictive control strategy combining a neural network for plant identification and a nonlinear programming algorithm for solving nonlinear control problems is proposed. A constrained nonlinear optimization approach using successive quadratic programming cooperates with neural identification network is used to generate the optimum control law for the complicate continuous/batch chemical reactor systems that have inherent nonlinear dynamics. Based on our approach, we developed a neural model predictive controller(NMPC) which shows excellent performances on nonlinear, model-plant mismatch cases of chemical reactor systems.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.561-566
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• 2003

In this study, to predict the behavior of RC beam strengthened with Carbon fiber reinforced polymer(CFRP) plate, analytical program considering material non-linearity is developed. Strain compatibility and force equilibrium are applied and internal forces of constitutive material are calculated using nonlinear stress-strain relationship. Also, to certainty the reliability of analytical program, deflection, strain of CFRP plate, change of neutral axis on cross section and crack distribution at failure are compared with those of experiment, and each results are almost coincident.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.313-320
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• 1998

The critical speed of a train running on the straight railway track is investigated by in-house program. The program is developed to find out nonlinear critical speed and it bases on the bifurcation theory. As a result, it is found that nonlinear critical speed exists on the lower speed band than linear critical speed and this fact imply a possibility of induction of a big accident.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.3 s.49
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• pp.65-75
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• 2006

Nonlinear pushover analysis is used to evaluate the earthquake response of building structures. To accurately predict the inelastic response of a structure, the prescribed story load profile should be able to describe the earthquake force profile which actually occurs during the time-history response of the structure. In the present study, a new modal combination method was developed to predict the earthquake load profiles of building structures. In the proposed method, multiple story load profiles are predicted by combining the modal spectrum responses multiplied by the modal combination factors. Parametric studies were performed far moment-resisting frames and walls. Based on the results. the modal combination factors were determined according to the hierarchy of each mode affecting the dynamic responses of structures. The proposed modal combination method was applied to prototype buildings with and without vertical irregularity. The results showed that the proposed method predicts the actual story load profiles which occur during the time-history responses of the structures.

• Journal of the Korean Data and Information Science Society
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• v.20 no.2
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• pp.411-423
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• 2009

In the current paper, by extending Verall (1990)'s work, we propose a new Bayesian model for analyzing run-off triangle data. While Verall's (1990) work only account for the calendar year and evolvement time effects, our model further accounts for the "absolute time" effects. We also suggest a Markov Chain Monte Carlo method that can be used for estimating the proposed model. We apply our proposed method to analyzing three empirical examples. The results demonstrate that our method significantly reduces prediction error when compared with the existing methods.