• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.4
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• pp.365-375
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• 2017

Approximately 250 marine pollution accidents involving oil and HNS spills are reported every year in the Republic of Korea. It is necessary that a strengthen of specialization of marine pollution response personnel on marine pollution response due to a diminution of damage when a major oil and HNS spill incident occurred, as in the case of the M/V Heibei Spirit and the M/V Maritime Maisie. In regard to this, the International Maritime Organization (IMO) has planned to revise the OPRC Model Training Course to strengthen expertise for oil spill incident responses. Through a comparison of curriculum with the Korea Coast Guard Academy (KCGA) program, a revised IMO Model Course and the OSRL training institute, this study recommends the following improvements for the education program of the KCGA in response to oil spills. This study suggests several options in line with this approach to revise the oil spill response education curriculum, exercise, discussions and making materials. Accreditation of the KCGA as an institute that provides an IMO Model training course developed according to the revised IMO Model Course material is proposed.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.3
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• pp.706-717
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• 2015

Marine casualties and environmental pollution have increased recently. Especially, the rate of incident of Coastal tankers is higher, but the assessment tool for safety management system is lack in this fields. However Oil Major Vetting System being professional assessment tool for tanker is widely applied in ocean going tanker by the worldwide Oil Majors. According to the analysis of the marine tankers' incidents which applied Oil Major Vetting System, the incidents were reduced rapidly for recent about 5 years. Using Oil Major Vetting System is helped to improve safety management and to prevent marine incidents. Therefore if applying a parts of the Oil Major Vetting Systems to the coastal tankers' Safety Management System, the Coastal tankers incidents would be reduced and improved gradually.

• Journal of Ocean Engineering and Technology
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• v.22 no.6
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• pp.7-12
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• 2008

The present study numerically investigates the effect of the shape of absorbing revetment on wave overtopping rate under regular and irregular incident waves. At first, the numerical model developed by Hur and Choi(2008), which considers the flow through a porous medium with inertial, laminar and turbulent resistance terms, directly simulates Wave-Structure-Sandy seabed interaction and can determine the eddy viscosity with LES turbulent model in 2-Dimensional wave field (LES-WASS-2D), is validated when compared to experimental data. Numerical simulations are then performed to examine the effect of the shape of absorbing revetment and incident wave conditions on wave overtopping rate. The numerical result shows that the wave overtopping rate decreases with the slope gradient of absorbing revetment under both regular and irregular waves. In addition, the effects of mean grain size and porosity of absorbing revetment, incident wave period and crest height on wave overtopping rate are discussed.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.401-406
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• 2011

In this study, generation methods of oblique incident wave are newly proposed and examined using the fully non-linear numerical model with non-reflected wave generation system(LES-WASS-3D). In order to verify, free surface elevation and horizontal velocities are compared with $3^{rd}$ -order Stokes wave theory in 3-D oblique incident wave field. As a results, it is revealed that the numerical results by newly proposed technique are in good agreement with the theory.

• The Journal of the Acoustical Society of Korea
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• v.22 no.3E
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• pp.133-140
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• 2003

A time series simulation is presented by a ray approach for the simulating the received waveform of a broadband acoustical signals interacting with the ocean boundaries. The environment is assumed to be horizontally stratified, and the seafloor is described in terms of homogeneous fluid half-space. The ray approach includes the effects of reflection from the air-water, water-sediment interface and phase shifts due to boundaries interaction. To generate time series, we assume that the acoustic energy propagates from source to receiver along eigenrays and represent the action of the bottom on the incident wave by a linear filter and characterized in the frequency domain by the transfer function. As example application, the time series for an explosive source in a shallow water environment is calculated and analyzed in terms of acoustical process. good agreement with measured time series is demonstrated.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.3
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• pp.141-147
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• 2006

A newly designed floating breakwater made of Polyethylene with considering the introduction of new material for being harmony with environment and stability of the floater is developed for a marine ranching. In this study, the new concept in which incident wave dissipates its energy due to the vortex shedding by passing through the pipes and sheets is selected for wave breaking mechanism. Model experiment in order to te st its capability is performed for the regular and irregular waves in ocean engineering basin. Good capability to break the incident wave within the 6 seconds of period and 1 m of height is shown. Breaking efficiency for long period wave is not so good in regular and irregular wave. The results of this study will contribute to the design and construction of the floating breakwater.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.8
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• pp.743-749
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• 2015

In this paper, we describe the dynamic tumble-stability analysis of a seabed-walking robot named Crabster (CR200) in forward-incident currents. CR200 is designed to be operated in tidal-current conditions, and its body shape is also designed to minimize hydrodynamic resistances considering hydrodynamics. To analyze its tumble stability, we adopt the dynamic stability margin of a ground-legged robot and modify the definition of the margin to consider tidal-current effects. To analyze its dynamic tumble stability, we use the estimated hydrodynamic forces that act on the robot in various tidal-current conditions, and analyze the dynamic tumble-stability margin of the robot using the estimated results obtained for the various tidal-current conditions. From the analyses, we confirm the improved tumble stability of the robot according to the movement of the tumble axis caused by the supporting points of the legs.

• Journal of Ocean Engineering and Technology
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• v.33 no.1
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• pp.68-75
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• 2019

A low-crested structure (LCS) is an excellent feature not only because it provides shore protection but also because it is fully submerged. However, in order to properly control waves, it is necessary to maintain a certain range of crest height and width in consideration of the wave dimensions at the installation area. According to previous studies, an LCS has some wave breaking effect when the crest width is more than a fourth of the incident wavelength and the crest depth is less than a third of the incident wave height. In other words, if the crest width of the LCS is small or the crest depth is large, it cannot control the wave. Therefore, when an LCS is installed in a large sea area with a great tidal range in consideration of the landscape, waves cannot be blocked at high tide. In this study, the hydraulic performances of a typical trapezoidal LCS with a constant crest height and a low-crested structure with an adjustable crest height, which was called a tide-adapting low-crested structure (TA-LCS) in this study, were compared and evaluated under various wave conditions through hydraulic experiments. It was found that the wave transmission coefficients of the TA-LCS at high tide were lower than the values for the typical LCS based on empirical formulas. In addition, the hydraulic performances of the TA-LCS for wave reflection control were 12.9?30.4% lower than that of the typical LCS. Therefore, the TA-LCS is expected to be highly effective in controlling the energy of incoming waves during high tide even in a macro-tidal area.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.1
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• pp.61-65
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• 2012

Once oil has spilled, oil spill responders use a variety of countermeasures to reduce the adverse effects of spilled oil on the environment. Mechanical methods of containment and recovery are preferred as the first response when the use of other methods fail or are ineffective. In these cases, the application of oil dispersants shall be use only as a last resort. While effectiveness of dispersants in removing oil form the sea surface is proven, the use of dispersants is controlled in almost all countries due to the toxicity of their active agents and the dispersed oil on the marine environment. However, according to reports, after dispersant application, no significant toxicity to fish or shrimp was observed in the field-collected samples. Moreover, the results also indicate that dispersant-oil mixtures are generally no more toxic to the aquatic test species than oil alone. During the Deepwater Horizon Incident, dispersants were applied to floating oil and injected into the oil plume at depth. These decisions were carefully considered by state and federal agencies, as well as BP, to prevent as much oil as possible from reaching sensitive shoreline habitats. Net Environmental Benefit Analysis for dispersant use assumed that dispersants appear to prevent long-term contamination resulting absence of oil in the substrate and will benefit marine wildlife by decreasing the risk of significant contamination to feathers or fur. Further study to use dispersants with scientific baseline is needed for our maritime environment which consistently threaten huge oil spill incidents occurrence.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.7
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• pp.846-853
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• 2016

This study prioritizes Noxious Liquid Substances (NLS) transported by sea via a risk-based database containing 596 chemicals to prepare against NLS incidents. There were 158 chemicals transported in Korean waters during 2014 and 2015, which were prioritized, and then chemicals were grouped into four categories (with rankings of 0-3) based on measures for preparedness against incident. In order to establish an effective preparedness system against NLS spill incidents on a national scale, a compiling process for NLS chemicals ranked 2~3 should be carried out and managed together with an initiative for NLS chemicals ranked 0-1. Also, it is advisable to manage NLS chemicals ranked 0-1 after considering the characteristics of NLS specifically transported through a given port since the types and characteristics of NLS chemicals relevant differ depending on the port. In addition, three designated regions are suggested: 1) the southern sector of the East Sea (Ulsan and Busan); 2) the central sector of the South Sea (Gwangyang and Yeosu); and 3) the northern sector of the West Sea (Pyeongtaek, Daesan and Incheon). These regions should be considered special management sectors, with strengthened surveillance and the equipment, materials and chemicals used for pollution response management schemes prepared in advance at NLS spill incident response facilities. In the near future, the risk database should be supplemented with specific information on chronic toxicity and updated on a regular basis. Furthermore, scientific ecotoxicological data for marine organisms should be collated and expanded in a systematic way. A system allowing for the identification Hazardous and Noxious Substances (HNS) should also be established, noting the relevant volumes transported in Korean waters as soon as possible to allow for better management of HNS spill incidents at sea.