• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7227-7236
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• 2015

The survey revealed that, due to the discharge characteristics of seafood wastewater, irregular inflow loads were caused, making it difficult to treat the wastewater safely. It is crucial for the operation of pressure and floating tanks for the treatment of high-concentration organic wastewater such as seafood wastewater. The survey of operation factors for the pressure and floating tanks revealed this: A/S ratio 0.05 (design criteria 0.01), the pressurized air pressure 8bar(design criteria 6bar), the pressure tank pressure 6bar (design criteria 4.5bar), and HRT 60sec(design criteria: 10sec). Also, the recirculation rate was changed to over 40%(design criteria: 30%), and the surface load rate was changed to under $13.7m^3/m^2{\cdot}hr$(design criteria: under $17.7m^3/m^2{\cdot}hr$); thus, compared to the initial design criteria, the operation factors were changed according to inflow characteristics, thus enhancing the pressure and floating tank performance. The survey of inflow load revealed BOD 140.7%, $COD_{Mn}$ 120.32%, and SS 106.3%, compared to the inflow design criteria, as well as T-N 135.5% and T-P173.3%, higher than the design criteria. The survey of the treatment facility annual operation cost revealed high portions in sludge treatment cost(27.7%) and chemicals costs(26.0%), and the sludge treatment cost will likely further increase due to the ban on ocean dumping. The unit cost for the treatment of seafood wastewater was found to be KRW 3,858 per ton, more than 27 times higher than the sewage treatment cost(KRW 142.6/ton), presumably because the seafood wastewater contains high-concentration organic substances and nutritive salts.

• Journal of the Korean GEO-environmental Society
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• v.13 no.7
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• pp.13-17
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• 2012

Recently, our ocean development paradigm is changing so that the development focus has been moved from the port facility developments to creating useful marine space. This paradigm accords well with the current green technology and helps the growth of service industries and the development from this paradigm can become a national land mark. Accordingly, the concept of creating marine waste landfill by the development of resource recycling technology has been introduced for eco-friendly space as an artificial island in future. Therefore, this study introduces the reactive vertical drainage method that is to pursue the purification of pollutants as well as stabilization of newly deposited soils in marine environments. To install the reactive vertical drainage piles for more effective feasibility and constructability, placements of drainage mid-layer are considered in the geotechnical viewpoint. Consolidation characteristics were evaluated by standard consolidation tests after several types of model test. As s result, the application of mid-layer drainage is strongly recommended in the reactive vertical drainage to quickly stabilize newly deposited soils. And vacuum consolidation method has better consolidation characteristic than vertical loading method in terms of the settlements predicted by additional stress for further use as an artificial island.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.5
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• pp.473-481
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• 2017

Seafarer sea survival training, such as basic safety refresher training and advanced safety refresher training, in accordance with the STCW Convention, is an indispensable program that can increase the crew survival rate during emergency situations at sea. It is important for crew members to carry out theoretical and practical training with various safety equipment in order to effectively train according to IMO model courses. Therefore, this study suggests the following measures to improve safety training facilities for seafarers by reviewing survival training requirements based on the IMO model course and comparing and analyzing related facilities based on operating cases from domestic and overseas training institutes. First, it is necessary to establish a training environment where seafarers can practice utilizing various, updated safety equipment such as marine evacuation equipment (slides, chutes, etc.). Second, it is necessary to construct an educational environment in which learners can directly or indirectly experience realistic emergency situations by installing marine environment simulation facilities with such equipment as a wave generator, rain fall device, wind generating device, etc. Third, it is also necessary to develop and expand customized training using virtual reality equipment in addition to experiential training, audiovisual training and simulation training.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.11a
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• pp.321-331
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• 2005

Recently. three-dimensional models have been used for aquatic dispersion of radioactive effluents in relation to nuclear power plant siting based on the Notice No. 2003-12 'Guideline for investigating and assessing hydrological and aquatic characteristics of nuclear facility site' of the Ministry of Science and Technology (MOST) in Korea. Several nuclear power plants have been under construction or planed. which are Shin-Korl Unit 1 and 2, Shin-Wolsong Unit 1 and 2, and Shln-Ulchin Unit 1 and 2. For assessing the aquatic dispersion of radionuclides released from the above nuclear power plants, it is necessary to know the coastal currents around sites which are affected by circulation of East Sea. In this study, a three dimensional hydrodynamic model for the circulation of the East Sea of Korea has been developed as the first Phase, which Is based on the RIAMOM. The model uses the primitive equation with hydrostatic approximation, and uses Arakawa-B grid system horizontally and Z-coordinate vertically. Model domain is $126.5^{\circ}E\;to\;142.5^{\circ}E$ of east longitude and $33^{\circ}N\;and\;52^{\circ}N$ of the north latitude. The space of the horizontal grid was $1/12^{\circ}$ to longitude and latitude direction and vortical level was divided to 20. This model uses Generalized Arakawa Scheme. Slant Advection, and Mode-Splitting Method. The input data were from JODC, KNFRDI, and ECMWF. The model ing results are in fairly good agreement with schematic patterns of the surface circulation in the East Sea The local current model and aquatic dispersion model of the coastal region will be developed as the second phase. The oceanic dispersion experiments will be also tarried out by using ARGO Drifter around a nuclear pelter plant site.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.262-267
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• 2017

The number of shops needed for the fabrication of a sphere type cargo tank for an LNG carrier is proportional to the size of the tank to be constructed. Due to the limitations of facility investment, it is difficult to fabricate various size tanks with a perfectly spherical shape in the (factory). An efficient method of increasing the capacity of the cargo tank is to extend the conventional sphere type LNG tank vertically by inserting a cylindrical shell structure. In this study, equations for the dynamic pressure distribution due to horizontal acceleration are derived for a sphere type LNG tank with central extension. The derived equations can be easily applied to the design and structural assessment of a sphere type LNG tank with central extension. Furthermore, the results of this study can be combined with the static design loads previously reported by Shin & Ko [9], in order to establish a simplified analysis method which enables a precise initial estimate to be obtained, thereby obviating the need for a time consuming finite element analysis.

• Journal of Navigation and Port Research
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• v.35 no.8
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• pp.631-636
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• 2011

Stable power supply to a light mounted on a navigational buoy is indispensable factor because unstable power can lead to fatal marine accident. Despite the difference lies between onshore and offshore environment, as well as the power output characteristics, the PV(Photovoltaic) power generation system is designed by the independent onshore power generation system standards. Furthermore, the capacity of PV power generation system does not take into account the structural characteristics of the buoy in the sea. Therefore, the faulty design makes battery over-discharge owing to lack of the power generation and the battery can not supply stable power to the light. This paper introduces a design method for a power system of the PV powered buoy. The data has been acquired for 3 months period, which includes PV-generated electricity, power consumption and battery voltage from experimental buoy. Further, a power management features of the buoy has been analyzed based on the acquired data. From the analysis of the acquired data, it was evident that PV power generation system produces different electric power output depend on its installed environment - land and sea. Based on the analytical result, a design criterion has been proposed for the power system in the navigational buoy.

• Korean Security Journal
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• no.32
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• pp.95-122
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• 2012

The ocean in the 21st century is getting emphasized as a treasury of natural resources and a growth engine for the nation. And nations around the world have entered into the hyper-competition to take the initiative for those marine resources. Under the situation, the Korea Coast Guard is devoting itself with full force to protecting maritime sovereignty, ensuring maritime safety and security and preserving the marine environment. Purpose of this study is to analyze Maritime Policing Act of 2012 and their problems and to suggest improvement measures. Objectives of Maritime Policing Act of 2012 is national Defence, policing for maritime security, protection of marine natural resources and marine facility in territorial waters and exclusive economic zone(EEZ) of Korea. Limits of Maritime Policing Act of 2012 are as follows. First, As organization related rules in Maritime Policing Act of 2012 are not enough, Maritime police agency Act should be revised and enacted in order to cope with future administrative demands and legal ground. Second, Article 22 penal regulation is more severe than regulations of another Act. Third, Article 14 should be made improvement for pre-prevention through the pre-report and the establishment of prohibition boundary in maritime demonstration.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.169-177
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• 2017

Recently, as the size of transportation vessels has increased, there is a growing need for securing the front-water depths of existing port facilities. The method of deepening front-water depth is securing the depth of the port facility, and it is reinforced by grouting after excavating the rubble-mound to the required depth. The purpose of this study is to investigate the reinforcing performance and filling performance of thixotropic grout as a grouting material for reinforcing rubble-mound. Compressive strength tests were carried out for two types of thixotropic grout, and 5 specimens with a diameter of 400 mm and a height of 530 mm were manufactured and evaluated for filling performance. The required strength of reinforced rubble-mound required to ensure the safety of the structure is 6 MPa. All the thixotropic grouts used in this study were found to satisfy the required strength over 9 MPa at 7 days of age. As a result of visual observation of filling state of the filling performance test specimens, it was confirmed that the thixotropic grout was well filled up to the desired fillet height.

• Journal of Navigation and Port Research
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• v.36 no.5
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• pp.401-407
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• 2012

The purpose of this study was to examine the preferences to yacht tourism and perceptions to importance of yacht tourism industry's activation strategies from consumers perspectives. In order to such a purpose, this study employed survey methodology with a total of 300 visitors to yacht facility and beach located in B metropolitan city. With 265 usable questionnaires, data collected were analyzed using descriptive statistics such as frequency, percentage, mean and standard deviation. Accordingly, following findings were derived from current study. First, 32% of participants had yacht tourism experiences and more than 64% of them had willing to purchase yacht tourism products in the future, which indicates optimistic increases in yacht tourism demand. In addition, amount of willingness to pay for yacht tourism was less than 100 thousand Won per day. Second, the most preferred product was a yacht training and experience program, and preferred time for yacht tourism was weekend and or vacation with the period of one day or one night and two days. The main motivation was to spend leisure time and enjoyment with accompanying persons of family or friend members. Third, consumers' restriction factors included high expenditures, time consuming and lack of various yacht tourism products but their selection attributes included low expenditures, associated tourism products and quality of yacht tourism products. Finally, the most important activation strategies included the development of yacht tourism products, building yacht tourism conditions and establishing marketing strategies, but the least important activation strategies from consumers views included policies, experts and facilities.

• Journal of Navigation and Port Research
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• v.34 no.1
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• pp.51-57
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• 2010

When estimating the calmness in a harbor, it is important that diffraction and reflection of irregular waves should be exactly calculated. The basic equation of the numerical model in this study was used Mild-slope equation, which has the advantage of which non-linearity with great influence for the wave behavior can be considered, and a triangular mesh was generated by using finite element method. So as to verify the nonlinear effects, the results of the numerical model developed in this study are compared with the experimental and numerical results by other researchers. As a result, it is shown that the results in case of considering nonlinear wave are more exact for wave analysis than in case of not considering nonlinear wave. In order to apply this model, wave height distributions in Jumunjin fishery port installed a seawater-exchange breakwater are computed. From the results of this numerical analysis, when abnormal waves are intruded through the seawater-exchange breakwater, the results of the wave height distributions in the harbor are highly presented. Therefore, in order to get wave height low in the harbor, it is considered that the facility with the ability to protect the inflow of abnormal waves is needed.