• Title/Summary/Keyword: 동파력

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Dynamic Wave Pressure Study on a Recurved Offshore Structure (곡면 해양구조물에 작용하는 동파력 고찰)

  • Jo, Cheol-Hui
    • Journal of Ocean Engineering and Technology
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    • v.9 no.2
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    • pp.149-155
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    • 1995
  • This study is to investigate the dynamic pressure caused by breaking waves on a recurved offshore structure. A physical modelling was performed in a two-dimensional wave flume. The measuments from the physical modelling were compared with several known equations. The shock and secondary pressures were found to be dependent on water depth, breaking wave height and the size of the air pocket. The maximum pressure was recorded near the still water level and the secondary pressures near the recurved the recurved structure were found to be less than those experienced in a vertical offshore structure.

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Stability Analysis of Honeycomb Slit-Caisson under Dynamic Wave Force using Numerical Simulation (수치 시뮬레이션을 이용한 동파력을 받는 벌집형 유공케이슨의 안정성 해석)

  • Woo, Jin-Ho;Na, Won-Bae;Kang, Yoon-Koo
    • Journal of Ocean Engineering and Technology
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    • v.24 no.1
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    • pp.83-89
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    • 2010
  • This study presents a stability analysis procedure for caisson structures and a case study for a honeycomb slit-caisson. CADMAS-SURF was used to calculate the wave pressures based on an irregular wave with a 50-year period and the data for three regular waves obtained from a target site. Then, the irregular and regular wave pressures were used to obtain the dynamic responses (stresses) of the caisson structure using an explicit time integration program, ANSYS/LS-DYNA. Finally, the DNV code was used for structural and fatigue stability analyses.

An Improvement of Convergence Rate for Direct Model Reference Adaptive Control Systems (직접 모델 규범형 적용 제어계에 대한 수렴 속도 개선)

  • 김도현;최계근
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.20 no.1
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    • pp.37-44
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    • 1983
  • A class of adaptive control algorithms applied to discrete-time single-input single-output deterministic linear systems is analyzed by using direct model reference adaptive control. Controller parameters are identified with weighted least square Method. And computer simulations reveal that proposed weighted least square method in which the value of depends on the identification error can be used regardless of the sufficient condition of reference input signal.

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A Clinical Study of Hypertrophic Pyloric Stenosis (비후성 유문 협착증의 임상적 고찰)

  • Kim, Yoon Hee;Jung, Myung Sup;Byun, Soon Ok
    • Clinical and Experimental Pediatrics
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    • v.45 no.11
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    • pp.1389-1396
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    • 2002
  • Purpose : This study was done to analyze the changes in the clinical conditions and the diagnosis of hypertrophic pyloric stenosis. Methods : We report a retrospective clinical analysis of 39 patients with hypertrophic pyloric stenosis from Jan. 1992 to Aug. 2001. The age and sex distribution, family and birth history, clinical symptoms, the ultrasonographic and the operative sizes of pyloric canals were compared. Results : The body weight was below the 3 percentile at admission in eight cases(20.5%). "Olive like mass" in right upper quadrant was palpated during physical examination in 23 cases(59%) and gastric peristaltic wave observed in six cases(15%). The ultrasonographic measurements showed that the pyloric muscle thickness to be $4.95{\pm}0.99mm$($mean{\pm}SD$), pyloric diameter $14.42{\pm}2.64mm$, and pyloric length $20.17{\pm}3.92mm$. Fredet-Ramstedt pyloromyotomy was employed in all cases. The operative measurements of the pyloric muscle thickness was $5.11{\pm}1.01mm$, pyloric diameter $15.01{\pm}2.47mm$, and pyloric length $22.32{\pm}3.43mm$. Conclusion : There was no significant difference between the ultrasonographic and operative measurements. Currently, the hypertrophic pyloric stenosis patients showed lesser clinical hallmarks of the disease. The earlier diagnosis using imaging studies before development of significant metabolic abnormalities is becoming an important factor that change the future outcomes of hypertrophic pyloric stenosis.