• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.143-146
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• 1999

특정 플랜트내에 원하지 않는 음이나 진동신호를 능동적으로 제어하기 위해 LMS의 Filtered reference와 Filtered error 방법으로 피드포워드 적응제어 시스템을 사용할 때 오차신호의 수렴특성을 플랜트의 추정 임펄스응답의 정확도로써 나타낼 수 있는 식을 제안하고 수치 시뮬레이션과 실험으로 그 유효성에 대해 기술한다. 플랜트내 음향전달계의 추정 임펄스응답의 안정성 평가식은 이미 W. Ren과 P. R. Kumar에 의해 발표되었으나[1], 그 평가방법은 플랜트내의 실제(True) 임펄스응답을 필요로하고있어 수치 시뮬레이션에서는 가능한 방법이지만 임펄스응답의 측정이 불가능한 실제의 적응제어 시스템에 적용하는 것은 곤란하다. 따라서, 플랜트의 추정 임펄스응답을 크로스스펙트럼법(Cross-Spectrum)으로 추정하여 그 임펄스응답을 피드포워드 적응제어 시스템에 적용했을 때 안정성 여부를 평가하고, 또한 오차신호의 수렴특성을 Filtered reference와 Filtered error 방법에서 각각 확인하였다. 수치 시뮬레이션 결과와 실험 결과가 일치함을 확인하였다.

• Journal of dental hygiene science
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• v.7 no.3
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• pp.167-177
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• 2007

The purpose of this study was to obtain basic data for dental implants prosthetic maintenance care after analysis perceptions of dental implants. A question was used to questionnaire by 210 dental patients at five dental clinics in the Jinju-city. In conclusion, 1. The knowledge level about implant is 'Never'(35.7%). 2. A feeling of unrest during implant surgery is 'pain'(37.6%). 3. The expectation level about dental implants function is 70% of natural teeth(36.2%). 4. The main function of implant teeth is 'mastication'(70.5%). 5. The implant hygiene supplies for the dental implants maintenance is 'proximal brush'(60%). 6. The important maintenance attitude for the dental implants is 'regularly dental examination'(42.9%). 7. The interval regularly for implant examination is 'six monthly'(44.8%).

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2003.06a
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• pp.149-152
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• 2003

플랜트 모델이나 경험에 근거하여 설계된 퍼지제어기를 실제 플랜트에 적용할 경우, 모델링 오차와 플랜트에 대한 관련지식의 부족으로 만족할 만한 제어 결과를 나타내지 못할 경우가 있다. 이 경우 제어성능을 향상시키기 위해 제어기의 제어인자를 다시 조정하여야 하고, 이 조정과정은 시행착오 방법으로 수행되기 때문에 많은 시간과 비용을 필요로 한다. 본 논문에서는 정규화 된 오차와 오차 변화량를 사용하여 플랜트 응답에 따라 입력과 출력의 적절한 스케일 계수를 조정하는 퍼지제어기를 제안한다. 정규화 된 오차를 출력 소속함수의 중심과 폭에 곱해 출력 범위를 재조정하고, 플랜트 응답에 의해 입력의 스케일 계수를 결정한다. 이를 확인하기 위해 2차 플랜트에 적용하여 모의 실험을 수행하였다.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.05a
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• pp.390-395
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• 2003

PMSM 드라이브의 벡터제어를 위한 속도제어기는 일반적으로 PI 알고리즘을 사용한다.［1］PI 알고리즘에서는 플랜트의 동적 특성을 동정하기 위하여 연속적인 측정이 가능한 플랜트 파라미터의 자동동조 또는 적응 알고리즘을 추가하여 사용하기도 한다. 그러나 PI 제어기는 플랜트의 변동이 발생하여 연속적으로 적응추종을 해야할 경우, 계산이 매우 복잡하고 응답특성이 저하된다.(중략)

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.1
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• pp.7-16
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• 2019

In this paper, for a seismic analysis of an offshore subsea manifold, Response Spectrum Analysis(RSA) and Time History Analysis(THA) were conducted under a various analysis conditions. Response spectrum and seismic design procedure have followed ISO19901-2 code. In case of THA, The response spectrum were converted into artificial earthquake history and both of Explicit and Implicit solvers were used to examine the characteristics of seismic analysis. For the verification, Various seismic analysis methods were applied on a single degree of freedom beam model and a simplified model of the actual manifold. The difference between the results of RSA and THA on the simplified manyfold model evaluated for the analysis of the actual manifold. Because THA is impossible in case of real complex structure such as a manifold, Safety of the actual manifold structure was accessed by using the RSA and the difference between the results of RSA and THA from the simplified model.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.5
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• pp.125-133
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• 2006

This paper presents comparison results of Step Response Model of Dynamic Matrix Control(DMC) for a drum-type boiler-turbine system of a fossil power plant. Two possible kinds of step response models are investigated in designing the DMC, one is developed with the linearization of theoretical model and the other is developed with the process step-test data. Then, the control performances of each model-based DMC are simulated and evaluated. It is observed that the simulation results with the step-response model based on the test data show satisfactory results, while the linearized model is not suitable for the control of boiler-turbine system.

• Computational Structural Engineering
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• v.10 no.3
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• pp.52-57
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• 1997

본 고에서는 부유구조물의 특징과 설계시 고려사항, 작용하는 하중, 구조응답 추정방법 등을 살펴보았다. 현재 국내에는 해상에 설치된 부유구조물은 아직 없으나 조선소에서 해상 발전 플랜트나 담수화설비 등을 수출한 실적은 있다. 그러나 설계기술의 많은 부분을 외국에 의존하고 있어 부유구조물의 설계 및 동적 구조응답해석 분야에 대한 국내의 많은 연구가 요구된다 하겠다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.5
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• pp.317-324
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• 2022

In this paper, an analysis method that considers the initial static displacement of structural members using an equivalent single-degree-of-freedom system is presented. Newmark's dynamic analysis algorithm was improved to consider the effect of the initial static displacements of structural members. The effect of the initial static displacement on the maximum response according to the assumed duration of the blast load and natural period of the member was investigated. The effects of positive and negative static displacements on the maximum dynamic responses of structural members subjected to a positively applied blast load were also studied. Modified response charts for the shock-type and pressure-type waves are presented so that static displacements can easily be considered. Using a design example, we demonstrate the significance of the modified response chart that considers the static displacement. Based on the results of this study, the maximum response of a the structural member can be easily obtained whilst considering its initial static displacement. The modified response chart presented in this study can be used for the structural design of plants and military facilities.

• Journal of Ocean Engineering and Technology
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• v.33 no.3
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• pp.214-221
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• 2019

A series of model tests was performed to evaluate the survivability of an articulated tower-type buoy structure under harsh environmental conditions. The buoy structure consisted of three long pipes, a buoyancy module, and top equipment. The scale model was made of acrylic pipe and plastic with a scale ratio of 1/22. The experiments were carried out at the ocean engineering basin of KRISO. The performance of the buoy structure was investigated under waves only and under combined environmental conditions from sea state (SS) 5 to 7. A nonlinear time-domain numerical simulation was conducted using the mooring analysis program OrcaFlex. The survivability of the buoy was analyzed based on three factors: the pitch motion, submergence of the top structure, and anchor reaction force. The model test results were directly compared to the results of numerical simulations. The effects of the sea state and combined environment on the performance of the buoy structure were investigated.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.4
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• pp.397-402
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• 2013

In this study, numerical hull form development of a platform supply vessel, a full scale with the overall length of 26.75m, was performed to predict a bare-hull resistance and a large scale of model tests with a 1/10 scaled model were conducted to verify the success of numerical results. Numerical analysis on heave and pitch motion as a function of encounter frequency and ship's speed for the prediction of seakeeping characteristics are also presented. The experiment results of resistance agreed well with numerical analysis. As a result in the motion response characteristics, the heave RAO indicates high values with the range of encounter frequency 1.8~2.0. The Pitch RAO indicates high motion response characteristics at Beaufort scale No. 3 and 4 in rough seas.