• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(2)
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• pp.945-946
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• 2005

• Safety and Health at Work
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• 제9권1호
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• pp.42-52
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• 2018

Background: Maintenance operations on-board ships are highly demanding. Maintenance operations are intensive activities requiring high man-machine interactions in challenging and evolving conditions. The evolving conditions are weather conditions, workplace temperature, ship motion, noise and vibration, and workload and stress. For example, extreme weather condition affects seafarers' performance, increasing the chances of error, and, consequently, can cause injuries or fatalities to personnel. An effective human error probability model is required to better manage maintenance on-board ships. The developed model would assist in developing and maintaining effective risk management protocols. Thus, the objective of this study is to develop a human error probability model considering various internal and external factors affecting seafarers' performance. Methods: The human error probability model is developed using probability theory applied to Bayesian network. The model is tested using the data received through the developed questionnaire survey of >200 experienced seafarers with >5 years of experience. The model developed in this study is used to find out the reliability of human performance on particular maintenance activities. Results: The developed methodology is tested on the maintenance of marine engine's cooling water pump for engine department and anchor windlass for deck department. In the considered case studies, human error probabilities are estimated in various scenarios and the results are compared between the scenarios and the different seafarer categories. The results of the case studies for both departments are also compared. Conclusion: The developed model is effective in assessing human error probabilities. These probabilities would get dynamically updated as and when new information is available on changes in either internal (i.e., training, experience, and fatigue) or external (i.e., environmental and operational conditions such as weather conditions, workplace temperature, ship motion, noise and vibration, and workload and stress) factors.

• 한국가시화정보학회지
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• 제13권3호
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• pp.3-9
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• 2015

• 해양환경안전학회지
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• 제29권5호
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• pp.427-434
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• 2023

굴은 패류 양식생산량 중 가장 큰 비율(평균 76%)을 차지하는 중요한 양식생물이다. 본 연구에서는 자란만의 굴 양식장에 대해, 수온, 염분, 해수 유동, DO, SS, Chl.a를 어장적지평가 인자로 활용한 서식지 적합 지수(Habitat Suitability Index, HSI)를 산정하여 최적 서식지를 탐색하였다. 조사결과 만 입구가 넓고 해수 유속이 빠르게 나타난 대상해역 남동쪽에서 만 내측으로 갈수록 적합한 서식지로 나타났고, 굴의 생산량과 본 연구의 HSI는 0.710(p<0.05)의 유의한 상관성을 보였다. 만 내의 원활한 해수 교환으로 먹이공급 등 양식생물 성장에 도움을 주는 해수 유동은 굴 생산량과 높은 상관성(0.709, p<0.05)을 보여 Chl.a보다 서식 적합도에 더 큰 영향을 미치는 것으로 나타났다. 본 연구 결과는 양식장 재배치 등 효율적인 연안어장 보전, 이용과 관리에 도움이 될 수 있을 것으로 판단된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2817-2822
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• 2007

The purpose of this paper is to study the influence of operating condition and ejector geometries on the hydrodynamics and on the mass transfer characteristic of ejector. The CFD results were validated with available experimental data. Flow field analyses and predictions of ejector performance were also carried out. Variation on the operating conditions was made by varying the gas-liquid flow rate ratio in the range of 0.2 to 1.2. The ejector configuration was also varied on the length to diameter ratio of mixing tube ($L_M/D_M$) in the range of 4 to 10. CFD studies show that at $L_M/D_M$ 5.5, the volumetric mass transfer coefficient increases with respect to gas flow rates. Meanwhile, at $L_M/D_M$ 4, the plot of volumetric mass transfer coefficient to gas-liquid flow rates ratio reach maximum at gas-liquid flow rates ratio of 0.6. This study also shows that volumetric mass transfer coefficient decrease with respect to the increase of mixing tube length.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2708-2713
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• 2007

The aim of this paper is further studies to achieve deeper understanding in this field. First investigate the influence of operating conditions and design parameters on the hydrodynamics and the mass transfer properties of a loop reactor. This paper provides a literature review on the ejectors applications in the mixing system. A number of studies are grouped and discussed in several topics such as the background, theory of ejector, mixing characteristics, optimization of the system. Since the high efficiencies reactor using ejector widely used in gas-liquid system, especially in a number of chemical and biochemical processes. This is due to their high efficiency in gas dispersion resulting in high mass transfer rate and low power requirements. Thus ejector has been applied to the mixing system. An investigation on hydrodynamics and mass transfer characteristics of gas-liquid ejector has been carried out using three-dimensional CFD modeling.

• 해양환경안전학회지
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• 제29권7호
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• pp.992-1001
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• 2023

OWEC(Overtopping Wave Energy Converter)는 월파된 파도를 이용한 파력발전시스템이라한다. OWEC의 성능 및 안전성은 파고, 주기 등 파도의 특성에 의해 영향을 받는다. 따라서 해역 특성에 따른 OWEC의 최적 형상과 구조안전성에 관한 연구가 필요하다. 본 연구에서는 울릉읍 연안 해양 환경 데이터를 이용하였으며, SPH(Smoothed Particle Hydrodynamics) 입자법 해석을 통해 기존 케이슨 하부 구조에 변화를 준 모델 4개를 비교하여 월파 효율을 분석하였다. 그 결과, 하부 구조의 변경 및 경량화가 가능함을 확인하였다. 최적화 해석을 통해 설계 하중에 내하력을 가지는 하부 구조인 새로운 트러스형 구조를 제안하였다. 이후 부재 직경 및 두께를 설계변수로 하는 사례 연구를 통해 허용응력조건 하에서 구조 안전성의 확보를 확인하였다. 주기적인 파랑 하중을 받기 때문에 제안하는 구조의 고유 진동수와 해당 해역의 파주기를 비교하였으며, 1년 재현 주기의 파랑을 하중으로 한 조화응답해석을 수행하였다. 제안하는 하부 구조는 동일 가진력에서 기존 설계 대비 응답의 크기가 감소하였으며, 기존 대비 32% 이상의 중량 절감을 수행하였다.

• 수산해양교육연구
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• 제28권1호
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• pp.172-179
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• 2016

The study of Mobile MGIS (Marine Geographic Information System) based on the Android Mobile Platform is mainly performed on effective methodologies which transform real world data to computing world data. Mobile GUI system has its own target on reliable data service by acquisition of geometric information using EFDC (Environmental Fluid Dynamics Code) Model, accurate measurement and graphical visualization. Even simple visualizations can aid in the interpretation of complex hydrodynamic relationships that are frequently encountered in the marine environment. The Mobile MGIS provides an easy way for hydrodynamics geoscientists to construct complex visualizations that can be viewed with free software. This study proposes a Mobile GUI MGIS using EFDC Model result of Seomjin River estuary. Finally, we design a Seomjin River estuarine Coastal Waters Mobile MGIS integrating above data models. It must adds more ecological information and the various service item for approach more easily in order to user.

• 한국해양환경ㆍ에너지학회지
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• 제1권1호
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• pp.66-82
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• 1998

해양오염 사고시 유출유의 수거를 위하여 사용되는 유회수기에 대하여 고찰하였다. 논문의 주요 내용은 (1) 유회수기의 종류, 장단점, 성능지표 및 시장현황에 대한 개괄적인 설명과 (2) 유회수 성능에 영향을 미치는 인자들에 대한 고찰, 그리고 (3) 유회수기 분야에 대하여 현재까지 발표된 논문들에 대한 핵심 아이디어들을 소개하였다. 끝으로 (4) 유체역학적 관점에서 본 유회수기의 특성과 해양, 토목, 기계등 유사관련분야의 연구결과가 유회수기 해석에 어떻게 이용될 수 있는지에 대하여 고찰하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제3권2호
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• pp.136-140
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• 2011

Monitoring of water surfaces through permanent measurement of hydrodynamic and meteorological data is one of the main requirements in safe and sustainable water management. The Caspian Sea, the major surface water body in Iran, significantly affects more than 600 km of urban and industrial coastline. In the present work, an integrated marine monitoring network for the entire southern coastline of the Caspian Sea was developed. The main design concerns centered on the network measuring components and data recording, checking, filtering, gap recognition, and transferring systems. Four coastal monitoring stations were assigned, along with two regional collecting stations and one central data station for gathering, checking and delivering recorded data at different access levels. Applicable guidelines on selection of measuring devices for both shallow and deep water zones are presented herein.