• 대한조선학회논문집
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• 제61권2호
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• pp.125-134
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• 2024

The Safe Operating Envelope (SOE) combined with Short-Take-Off and Vertical Landing (STOVL) performance is an essential consideration of a light aircraft carrier for design of hull shape with excellent seakeeping performance in terms of naval air operations as well as traditional naval ship missions such as Transit and Patrol (TAP), and Replenishment at Sea (RAS) and so on. A variety of procedures are systematically combined to determine SOE considering rather complicated missions associated with operation of aircraft onboard. The evaluation of take-off and landing safety missions onboard should consider wind effect on deck and severer seakeeping indices and standards compared with conventional naval ships. In order to support take-off and landing missions, various support activities of the crews are required. So, additional evaluation is needed for indicators such as MSI(Motion sickness Index) and MII(Motion Induced Interruptions), which are quantitative indicators of work ability that appear as a result of motion response. In this study, a standard procedure is developed including the seaworthiness performance indicators, standards, and evaluation procedures that should be considered during design of STOVL aircraft carrier. Analysis results are discussed in terns of air-wake on deck as well as seakeeping indices associated with design parameter changes in view of conceptual design of a light aircraft carrier.

• 한국산업보건학회지
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• 제26권4호
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• pp.445-453
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• 2016

Objectives: The objective of this study is to assess relative safety level of the decompression tables in Ministry of Employment and Labor Public Notice No. 2014-28 in comparison with overseas decompression tables. Methods: Decompression tables in the Public Notice No. 2014-28 were compared with examples from Japan, the USA, Canada, and France in terms of ascent rate, surface intervals after exceptional exposures, oxygen decompression and allowable partial pressure, depth limits in air diving, no-decompression limits, and decompression time and methods. Results: Public Notice No. 2014-28 does not include air diving depth limits, exceptional exposure limits, mandatory surface intervals after exceptional exposures, oxygen decompression, and surface decompression schedules. Its decompression time was found to be the shortest among the five decompression tables. Conclusions: Public Notice No. 2014-28 has the lowest safety level in comparison with overseas decompression tables. Deck decompression chambers are not applicable due to no regulations on surface interval and oxygen use in the chamber for decompression.

• 한국음향학회지
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• 제43권1호
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• pp.60-71
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• 2024

본 연구는 일반적인 평평한 에틸렌 비닐 아세테이트(Ethylen Vinyl Acetate, EVA) 완충재의 형상을 변화시켜 다양한 차음소재와 조합하여 복합구조의 바닥충격음 변화를 조사하는 데에 목적이 있다. 바닥충격음 저감에 효과적인 완충재를 선정하기 위해 Flat, Deck, Cavity type의 EVA, EPS, PET 흡음재, PP판넬, 고무발판 등 다양한 완충재를 조합하여 뱅머신을 이용한 1차 실험을 진행하였다. 1차 실험 데이터에 대해 통계분석한 결과 완충재 두께가 40 mm에 가까울수록 바닥충격음 저감효과가 증가하였으며 PET 흡음재, PP시트, 고무발판 등을 조합한 복합완충재에서 바닥충격음 효과가 증가하는 것을 알 수 있었다. 이에따라 2차 실험에서 모든 복합완충재의 두께는 40 mm로 통일하였으며, 1차 실험에 사용된 Flat, Deck, Cavity type 및 EVA를 발판형태로 가공한 Mount type 등 4가지 형태의 복합완충재를 설계하였다. 또한, Mount type을 제외한 3가지 기본 형태에서 각각 PET 흡음재(7 mm)를 추가했을 시 바닥충격음 변화를 살펴보았으며, Mount type의 경우 EVA발판 개수에 따른 바닥충격음 변화에 대해 고무공 충격원을 이용한 2차 실험을 진행하였다. 모든 실험은 공인인증시험기관의 목업실험실에서 진행하였다. 실험 결과, 기본형태의 Flat, Deck, Cavity type에서 PET를 추가할 경우 통계적으로 경량 5 dB ~ 9 dB, 중량 1 dB ~ 5 dB의 저감효과가 나타난 것을 알 수 있었다. 특히, Mount type의 경우 발판 수가 36개 이상일 때 경량 및 중량충격음에서 우수한 것으로 나타났다. 또한, 4가지 기본형태에 따라 동탄성계수가 높아질수록 바닥충격음의 저감이 증가하는 것으로 나타났다.

• 대한조선학회논문집
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• 제52권1호
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• pp.8-18
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• 2015

Reduction of the fuel oil consumption and corresponding greenhouse gas exhausted from ships is an important issue for today's ship design and shipping. Several concepts and devices on the superstructure of a container ship were suggested and tested in the wind tunnel to estimate the air drag reduction. As a preliminary performance evaluation, air drag contributions of each part of the superstructure and containers were estimated based on RANS simulation respectively. Air drag reduction efficiency of shape modification and add-on devices on the superstructure and containers was also estimated. Gap-protectors between containers and a visor in front of upper deck were found to be most effective for drag reduction. Wind tunnel tests had been carried out to confirm the drag reduction performance between the baseline(without any modification) configuration and two modified superstructure configurations which were designed and chosen based on the computation results. The test results with the modified configurations show considerable aerodynamic drag reduction, especially the gap-protectors between containers show the largest reduction for the wide range of heading angles. RANS computations for three configurations were performed and compared with the wind tunnel tests. Computation result shows the similar drag reduction trend with experiment for small heading angles. However, the computation result becomes less accurate as heading angle is increasing where the massively separated flow is spread over the leeward side.

• 설비공학논문집
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• 제29권6호
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• pp.289-296
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• 2017

This study aimed to analyze the deck floor heating system of an outdoor swimming pool in terms of the thermal capacity/output and the surface temperature distribution based on the outdoor temperature, to design for anti-freezing during winter. Through the transient heat transfer simulation with PHYSIBEL and theoretical equations, the surface temperature distribution of the floor heating system at two outdoor conditions in Jeju, were calculated and evaluated. The results indicate that the specific thermal output required for maintaining $4^{\circ}C$ surface temperature at the design outdoor temperature of $0.1^{\circ}C$, was about $90W/m^2$. This performance analysis can be applied for future design criteria, including optimizations of system capacity and size.

• 대한조선학회 특별논문집
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• 대한조선학회 2011년도 특별논문집
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• pp.43-46
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• 2011

The noise characteristics of multi-purpose dive support vessel show the different patterns such as types of noise sources, accommodation arrangement and etc due to its operation. Especially, the tunnel and retractable thruster for the dynamic positioning should be considered at the noise analysis. The floating floor is selected as the main measure of noise reduction and is constructed at the deck near the noise sources. In this paper, the noise analysis of dive support vessel is based on the estimation of noise sources and floating floor and SEA (Statistical Energy Analysis) is used for analysis of the air-born noise and structure-borne noise. The noise analysis of air conditioning system is also carried out and the noise results of cabin room are reviewed.

• Nuclear Engineering and Technology
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• 제55권7호
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• pp.2504-2515
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• 2023

In past years the Paul Scherrer Institute (PSI, Switzerland) and the Karlsruhe Institue of Technology (KIT, Germany)) collaborated to develop a model to account for the active role of nitrogen in the air oxidation of a Zircalloy cladding. The "PSI-KIT Nitriding Model for Zirconium based Fuel Cladding" model was implemented at PSI into PSI-MELCOR 1.8.6. In order to make a preliminary evaluation of the effect of the new model on the evolution of full-scale spent fuel pool accidents, one spent fuel pool event was analyzed using the PSI research version of PSI-MELCOR 1.8.6, which includes the nitriding model. To adapt an existing input deck for the calculations, a sensitivity study was conducted to find an optimal nodalization for the analyses. The nitriding model results were compared to those calculated with the MELCOR 1.8.6-PSI without the new nitriding model. The results demonstrate the effect of the nitriding reactions in spent fuel pool accident progression. Moreover, they confirm the impact of ZrN formation during cladding oxidation in air when the oxidation reactions lead to oxygen starvation inside the fuel assemblies. The nitriding reaction led to higher chemical heat generation during the accident and to an earlier failure of the cladding than when the effect of nitrogen reactions was not considered. It should be noted that the nitriding model, as implemented in the PSI version of MELCOR 1.8.6 has not yet been conclusively validated. Thereby the results presented in this paper should be treated as a preliminary demonstration of the capabilities of the model.

• 콘크리트학회논문집
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• 제14권3호
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• pp.299-306
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• 2002

본 연구에서는 기존 교량의 신속한 유지보수를 위한 교면포장 덧씌우기용 라텍스개질 초속경 콘크리트를 개발하고자 하였다. 실험변수로는 국내 생산 초속경 시멘트를 이용하여 혼화제 인자로 라텍스 및 소포제 혼입률 변화를 선정하여 작업성, 강도발현 및 투수 특성을 고찰하고자 한다. 실험결과 동일 물-시멘트비 조건에서의 라텍스 혼입은 콘크리트의 슬럼프를 증대시켜 작업성을 유지하기 위한 단위수량을 감소시키는 것으로 나타났다. 소포제를 혼입하지 않을 때는 공기량이 8~9%로 나타났으나, 소포제를 1.6~3.2% 혼입함으로써 공기량이 2.0~3.8%로 감소되었으며, 이로 인해 압축강도가 10~20%정도 증진하였다. 라텍스의 양이 증가함에 따라 콘크리트의 휨강도는 증진되나, 압축강도는 다소 저하되었다. 그러나, 소포제의 혼입으로 타설 후 3시간 만에 교통개방을 위한 압축강도와 휨강도를 얻을 수 있었다. 라텍스를 일정량 이상 첨가할 경우 콘크리트를 불투수성의 재료로 평가할 수 있을 정도의 낮은 통과전하량을 나타내었다. 따라서 라텍스 개질 초속경 콘크리트는 구조물, 교량 포장의 덧씌우기 또는 보수재료로서 사용되어 질 수 있을 것으로 사료된다.

• 한국건설순환자원학회논문집
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• 제7권4호
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• pp.445-451
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• 2019

본 연구에서는 콘크리트 교면포장 재료로서 사용되는 라텍스의 단점인 경제성을 보완하고 자원재활용을 위해 괭생이모자반 기반의 자원순환형 폴리머 혼입에 따른 내구성능을 분석하였다. 본 연구 범위의 모든 배합조건에서 슬럼프 및 공기량은 품질기준은 만족하는 것으로 나타났으나, 분말 형태의 자원순환형 바이오 폴리머 적용시 슬럼프가 일부 저하되는 경향을 나타내었다. 압축강도 시험결과, 라텍스 혼입시 강도가 감소되었지만 바이오 폴리머 대체시 혼입율에 따라 6.3~24.4%의 강도 개선효과를 나타내었다. 내구성능 시험결과, 합성 폴리머 혼입시 가장 우수한 내구성능을 나타내었고, 바이오 폴리머 혼입시에는 혼입율이 증가할수록 내구성능이 우수한 경향을 나타내었지만 라텍스보다는 미소하게 낮은 것으로 확인되었다.

• 시스템엔지니어링학술지
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• 제11권1호
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• pp.33-39
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• 2015

This paper describes a development of aircraft carrier aviation support system architecture using DoDAF. The aircraft carrier, a warship performing a role of mobile sea air base in offensive and defense mission, is super system that is comprised of carrier itself and carrier-based airwing. Performing critical role in step with aviation operations in carrier-airwing interactions, the aviation support system of aircraft carrier is also system of systems. It requires a complex and integrated approach based on systems engineering in establishing concept of this complex systems. In this view, this study establishes an operational scenario and derives operational requirements by identifying aviation operations environment on deck of aircraft carrier. The study presents the operational architecture of the carrier aviation support system by using DoDAF and CASE tool CORE.