• Title/Summary/Keyword: 동요도

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A Study on the Roll Motion of a Ship in a Transient Irregular Wave (설계불규칙파중에서 선박의 횡동요에 관한 연구)

  • Han, Ju-Chull;Lee, Seung-Keon;Ha, Tae-Phil
    • Journal of Navigation and Port Research
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    • v.28 no.5
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    • pp.353-358
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    • 2004
  • A transient irregular wave was designed based on ISSC spectrum The designed wave was generated in the towing tank and ,the roll motion of a model was measured A method to predict the maximum roll motion, expected in the short-term sea state, was investigated with comparison of the theoretical and experimental results.

DENTAL COMPLICATIONS AND MANAGEMENT OF A PATIENT WITH NEUROBLASTOMA : SPLINT OF MANDIBULAR INCISORS WITH ROOT ANOMALIES USING MINI-SCREW (신경모세포종의 의학적 치료에 따른 치과적 합병증과 관리 : Mini-screw를 이용한 치근이형성 하악 절치의 고정술)

  • Cheon, Min-kyoung;Kim, Jae-hwan;Choi, Nam-ki;Kim, Seon-mi
    • The Journal of Korea Assosiation for Disability and Oral Health
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    • v.11 no.1
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    • pp.5-8
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    • 2015
  • Neuroblastoma is a common malignant tumor of the sympathetic nervous system in childhood, arises from embryonic neural crest cells. The period of tooth development is matched with peak times of diagnosis and treatment of neuroblastoma. The intensive multimodality treatment including radiotherapy and chemotherapy is used in patients with neuroblastoma has been shown to have late adverse effects and disturbances in dental development like tooth agenesis, microdontia, enamel hypoplasia and short roots. A 8-year old girl had been on medication and radiotherapy for neuroblastoma since she was 15 months old at Department Pediatrics, Chonnam National University Hospital. Oligodontia, microdontia, and short root formation was notable in clinical and radiological examination. Mobility of lower permanent incisor was detected and measured at about degree 2. Resin wire splint using mini-screw implantation on buccal alveolar bone was conducted for maintenance of mandibular incisors and alveolar bone. Excessive mobility has been eliminated and maintained well so far. Further treatment is planned for re-evaluation of mobility, preventing dental caries and regular oral hygiene management. Although we need further evaluation, this treatment could be one of alternative therapy for those who have similar dental anomalies.

Estimation of Hydrodynamic Derivatives of Submarine Model by Using VPMM Test (VPMM 시험을 이용한 잠수함 모형의 유체력 미계수 추정)

  • Jung, Jin-Woo;Jeong, Jae-Hun;Kim, In-Gyu;Lee, Seung-Keon
    • Journal of Navigation and Port Research
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    • v.38 no.2
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    • pp.97-103
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    • 2014
  • In these days, the world has been increasing navy forces such as aircraft carriers and high-tech destroyers etc. and the importance of submarines is being emphasized. Therefore, accurate values of the derivatives in equations of motion are required to control motion of the submarines. Hydrodynamic derivatives were measured by the vertical planar motion mechanism(VPMM) model test. VPMM equipment gave pure heave and pitch motion respectively to the submarine model and the forces and moments were acquired by load cells. As a result, the hydrodynamic derivatives of the submarine are provided through the Fourier analysis of the forces and moments in this paper.

Pneumonia due to tooth-like foreign body aspiration in a child with seizure disorder (경련성 질환을 가진 장애 아동에서 치아로 추정되는 이물질 흡인에 의한 폐렴)

  • Park, Minji;Lee, Ko-Eun;Lee, Jae-Ho
    • The Journal of Korea Assosiation for Disability and Oral Health
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    • v.14 no.1
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    • pp.26-30
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    • 2018
  • Aspiration of tooth can occur not only during dental treatment, but also due to factors like trauma or physiologic exfoliation of primary tooth. If this occurs, complications such as fever, cough, dyspnea, pain, and bronchitis can be appeared. 9 years-old girl with Lennox-Gastau syndrome visited the dental clinic for regular checkups. Calcified tooth-like material was observed in the chest PA x-ray, and maxillary left primary first molar was not observed in the patient's oral cavity. She had a history of hospitalization for pneumonia two months ago. Because it was considered that the tooth was likely to be aspirated and caused pneumonia, the extraction of remaining primary teeth with mobility was performed. It is necessary to reduce the risk of aspiration in patient with disabilities by performing active treatment such as removal of primary tooth with mobility or ill-fitting restorations.

Characteristic Analysis of Reduced Motion due to the Shape of Floating Structure (부유구조체 형상에 따른 동요감소 특성분석)

  • Lee, Du Ho;Jeong, Youn Ju;You, Young Jun;Park, Min Su
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.25 no.6
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    • pp.357-364
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    • 2013
  • In previous study, the hybrid floating structure composed of a pontoon and a semi-submersible was suggested to reduce the motions of floating structure. It was reported that the suggested hybrid floating structure could reduce the motions. However, the hybrid floating structure could not support enough buoyancy. In this study, the combination floating structure is newly suggested to resolve the problem. In order to adopt the shape of floating structures reducing the motions, the hydrodynamic analysis of various floating structures such as the pontoon, the hybrid and the combination of floating structure is carried out through hydrodynamic analysis program ANSYS AQWA. It is found that the combination floating structure is remarkably effective to reduce the motions compared to the other cases. Thus, the suggested combination floating structure may be a useful offshore structure for constructing a very large floating structure.

A Study on Development of an Anti-Rolling System for the Ship Stability Improvement (선박안정성 향상을 위한 횡동요 방지 장치 개발에 관한 연구)

  • Kim, Young-Bok;Lee, Kwon-Soon;Kim, Jun-Hyo;Chae, Gyu-Hoon
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.11 no.1 s.22
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    • pp.23-28
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    • 2005
  • We have investigated the usefulness cf active stabilizing system to reduce ship rolling under disturbances, using varying reaction cf the flaps. In the proposed anti-rolling system for a ship, the flaps as the actuator are installed on the stem to reject rolling motion induced by disturbances like wave. The action induced by flaps which depends on power of disturbances am take the ship balance. Especially, in this study we identify the controlled system under the undefined system structure using spectral analysis and experimental studies. Based on these informations, we design the controller to evaluate the usefulness of the proposed system.

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Wave Responses and Ship Motions in a Harbor Excited by Long Waves(I) (항만내 파도응답과 계류선박의 운동해석(I))

  • I.H. Cho;Hang-S. Choi
    • Journal of the Society of Naval Architects of Korea
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    • v.29 no.2
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    • pp.38-47
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    • 1992
  • The motion response of a ship moored in a rectangular harbor excited by long waves has been studied theoretically and experimentally. Within the framework of potential theory, matched asymptotic expansion techniques are exployed to analyze the problem. The fluid domain is divided into the ocean and the harbor regions for the analysis of wave response in a harbor without ship. The wave responses in both the ocean and the harbor sides are solved first independently in terms of Green's functions, which are the solutions of the Helmholtz equation satisfying appropriate boundary conditions. Slender body approximations are used to obtain the velocity jumps across the ship, which are associated with the symmetric motion modes of the ship. Unknowns contained in each solution are finally determined by matching at an intermediate zone between two neighboring regions. Theoretical results predict the ship motion qualitatively well. The main source of quantitative discrepancies is presumably due to real fluid effects such as separation at the harbor entrance and friction on harbor boundaries.

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