• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.4
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• pp.277-286
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• 2012

In the numerical simulation of wave fields using a multi-phase flow model that considers simultaneous flows of materials with different states such as gas, liquid and solid, there is need of an accurate representation of the interface separating the fluids. We adopted an algebraic interface capturing method called tangent of hyperbola for interface-capturing(THINC) method for the capture of the free-surface in computations of multi-phase flow simulations instead of geometrical-type methods such a volume of fluid(VOF) method. The THINC method uses a hyperbolic tangent functions to represent the surface, and compute the numerical flux for the fluid fraction functions. One of the remarkable advantages of THINC method is its easy applicability to incorporate various numerical codes based on Navier-Stokes solver because it does not require the extra geometric reconstruction needed in most of VOF-type methods. Several tests were carried out in order to investigate the advection of interfaces and to verify the applicability of the THINC method to wave fields based on the one-field model for immiscible two-phase flows (TWOPM). The numerical results revealed that the THINC method is able to track the interface between air and water separating the fluids although its algorithm is fairly simple.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.123-129
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• 2012

Cabotage means transportation of cargoes or passengers between two points within same country by vessel or aircraft which registered to foreign country. Cabotage regulation has justified by the protectionism in economic aspect and by national security in the defence of a country, thus most world's major countries including United States of America, Japan and European Union(outside EU) are executing cabotage. Even though Korean's controlled fleet ranked to 5th in the world, shortage and ageing of Korean domestic seafarers came to the restricted factor in the Korean domestic shipping. Resultingly Korean government permitted 530 Myanmarese and Indonesian seafarers to come on board in domestic vessel. In regarding to the Korean law, there are no direct relationship between boarding foreign crew in domestic vessel. However the baxic concept of cabotage will be spoiled by boarding foreign crew under the regulation of cabotage, so special treatment should be needed to cover the problems in coastal shipping arose form them. To minimize the problems derived from foreign crew, following actions are recommended; first, management skills of foreign crew are needed to overcome differences of communication and culture; second foreign crew supporting center should be established to counsel their difficulties; third, high level of manning companies should be promoted; forth, stabilized crew supply should be guaranteed by improving employment condition; finally, memorandum of understanding should be concluded between two countries to prevent seceders.

• Journal of Korean Port Research
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• v.11 no.2
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• pp.231-240
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• 1997

In the United States, a number of ocean outfalls discharge primary treated effluent into deep sea water and contribute for more efficient wastewater treatment. The long multiport diffuser connected by long pipe from a treatment plant discharge wastewater into deep water due to the steep slope of the sea bed. However, Plume discharged from the diffuser can have significant impacts on coastal communities and possibly immediate consequence on public health. Therefore, there have been growing interests about the dynamics of plume in the vicinity of the ocean outfalls. It is expected that the ocean outfall should be considered for more efficient and reliable wastewater treatments as soon as possible around coastal area in South Korea. A number of studies of plume ynamics have used various models to predict plume behavior. However, in many cases, the calculated values of plume behavior are in significantly poor agreement with realistic values. Therefore, in this study, it is recommended that improvements should be made in the application of the plume model to more simulate the actual discharge characteristics and ocean conditions. It should be noted that input parameters in plume models reflect realistic ocean conditions like waves as well as currents. In this study, as one of the new parameters, current and long wave-influenced plume rise and initial dilution have been taken into account by using simple linear wave theory under some specific assumptions for more reliable plume behavior description. Among the improved plume models approved by EPA (Environmental Protection Agency), the RSB(Roberts-Snyder-Baurngartner) and UM(Updated Merge) models were chosen for the calculation of plume behavior, and the variation calculated by both models on the basis of long period wave was compared in terms of plume rise and initial dilution.

• Fisheries and Aquatic Sciences
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• v.25 no.12
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• pp.626-636
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• 2022

Shellfish are exoskeleton-bearing aquatic invertebrates that consume various organic and inorganic substances floating in seawater through filter feeding. Heavy metals are known as absorbed and accumulated in seawater. Some of the toxic heavy metals are highly accumulated in seawater, and exposure to them can cause a variety of risks to the human body. Since Koreans like to eat seafood, they are more likely to be exposed to contaminated seafood with heavy metals. In this study, nine types of heavy metals were analyzed on ten different shellfish species in the coastal area of South Korea. The risk assessment was also done on shellfish in which heavy metals were detected. Zinc (Zn) and copper (Cu) were identified at an average of 56.7 mg/kg (6.70 to 466 mg/kg) and 13.2 mg/kg (0.064 to 143 mg/kg), respectively. Lead (Pb) average of 0.208 mg/kg (0.000750 to 1.02 mg/kg), cadmium (Cd) average of 0.454 mg/kg (0.0388 to 1.56 mg/kg) and mercury (Hg) average of 0.0266 mg/kg (0.00548 to 0.174 mg/kg) were identified. Additionally, arsenic (As), chromium (Cr), nickel (Ni), and silver (Ag) were also identified as average concentrations of 4.02 (0.460 to 15.0 mg/kg), 0.167 (< limit of quantification [LOQ] to 0.820 mg/kg), 0.281 (< LOQ to 1.46 mg/kg), and 0.158 mg/kg (< LOQ to 1.15 mg/kg). The result indicates that the monitoring results of heavy metals in most shellfish satisfied the Korean standard. However, Pb and Cd have exceeded some foreign standards, such as the United States and the EU. The permissible human exposure calculated using the heavy metal intake and detection amount was lower than the Joint FAO/WHO Expert Committee on Food Additives human safety standard, and the risk of heavy metals from shellfish consumption was at an acceptable level.

• Journal of Wetlands Research
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• v.26 no.1
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• pp.82-91
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• 2024

In this study, research cases related to blue carbon storage were collected and analyzed, and various definitions of blue carbon were considered in terms of spatiotemporal scope and scientific aspect. 444 papers were selected as research cases related to blue carbon storage, and analysis of the number of papers published by year/country and keywords was performed. Publication of papers related to blue carbon storage has continued to increase since 2011, and more than 50 papers have been published annually since 2018. The most publications by country were in Australia with more than 100 papers, and the United States and China also published more than 60 papers. Key terms related to "natural environment" and "storage characteristics" were analyzed in the sentences defined in the 23 papers that presented the definition of blue carbon. The natural environments where blue carbon was stored were mostly mangroves, salt marshes, and seagrass beds, and blue carbon repository included sediments and even plants themselves. The existing definition of blue carbon focused on the vegetation environment as the storage environment for blue carbon. However, since blue carbon is stored in the sediments of coastal wetlands, it would be appropriate to define the coastal ecosystem, including non-vegetated mudflats, as the storage environment for blue carbon.

• Journal of Fisheries and Marine Sciences Education
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• v.4 no.1
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• pp.30-46
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• 1992

Korea's first exploratory tuna fishing was done with a used longliner in 1957. Then the commercial fishing has been made steady headway since the 1960's and grown up to one of major tuna fishing countries in 1970's. The tuna fishing aimed primarily at acquiring foreign currency, then tuna was exported directly from the overseas fishing base. Tuna, however, has been gradually favored by Koreans as high-proteined foods according to the growth of GNP since the 1970's. In 1980, the canned tuna began to be produced and sold at home. And so the demand of raw tuna for cannaries has steeply increased not only for home but also for abroad, and stimulated the development of tuna purse seine fishery. The author carried out a study on the development of tuna purse seine fishery in Korea and countries concerned-the United States and Japan-because it is recognized to be significant for the further development of this fishery. Just as purse seining was originated in the United States, so tuna purse seining was also pioneered by Californian fishermen in the west coastal waters of the United States (Eastern Pacific Ocean). They started to produce the canned tuna in the early 1900's, and the demand for raw tuna began to be increased rapidly. In those days, tuna was mostly caught by pole-and-line, but the catch amount was far away from the demand. To satisfy this demand, they began to try out fishing tuna by the use of purse seine which had been born in the eastern waters in the 1820's and applied to catch white fishes in the western waters of the United States in those days. Even though their trial was technically successful through severe trial and error, a new problem was raised on the management of tuna resource and the preservation of porpoise which was occassionally caught with tuna. Then the Inter-American Tropical Tuna Commission (IATTC) was established by countries neighboring to the United States in 1950 and they set up the Commission's Yellowfin Regulatory Area (CYRA) and regulated the annual quota for yellowfin. Then, American owners tried to send their seiners to the Western African waters to expand the fishing ground in 1967 and to the Centeral-Western Pacfic in 1974, and the fishing ground was widely expanded. The number of the United States' purse seiners amounted to about 150 in 1980, but the enthusiasm was gradually cooled thereafter and the number of seiner was decreased to 67 in 1986. The landing of tuna by purse seiners in the United States after 1980 maintains 200 thousands M/T or so with a little increase despite the decreasing of domestic seiners. This shows that the landing by foreign seiners are increasing, compared with the landing by domestic seiners are decreasing. In Japan, even though purse seining was introduced in 1880, they had fished tuna by longline and pole-and -line until the tuna purse seining was introduced from the United States again. In the 1960's, Japanese tuna seiners made the exploratory fishing in the South-western Pacific and West African waters with a limited success. In 1971, the government-funded research center "JARMRAC" conducted the exploratory fishing which extended to the Central American waters, the Asia-Pacific Region and the South-western Pacific. It had also much difficulties, till they improved the fishing gear adaptable to the new fishing condition in the South-western Pacific. Japanese government has begun to licence 32 single seiners and 7 group seiners since 1980 and their standard has lasted up to now. The catch in the Pacific Islands Region amounted to 160 thousands M/T in 1986. Korea's tuna purse seine fishery was originated in 1971 by Jedong Industrial Co., Ltd. with three used tuna purse seiners purchased from the United States, and they began to fish in the Eastern Pacific, but failed owing to the superannuation of vessel and the infancy of fishing technique. The second challenge was done by Dongwon Industrial Co., Ltd. in 1979, with one used seiner purchased from the United States, and started to fish in the Eastern Pacific. Even though the first trial was almost unsuccessful but they could obtain the noticeable success by removing the vessel to the South-western Pacific in 1980. This success stimulated the Korean entherprisers to take part in this fishery, and the number of Korean tuna purse seiners has been increased rapidly in accordance with the increased demand for raw tuna. The number of vessels actually at work amounted to 36 in 1990 and they operate in the South-western Pacific. The annual catch of tuna by purse seiners amounted to 170 thousands M/T in 1990 and ranked to one of the major tuna purse seining countries in the world.

• Strategy21
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• s.43
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• pp.29-55
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• 2018

Arctic sea ice has been retreating as a result of the global warming. Arctic sea ice extent for April 2018 averaged 13.71 million square kilometers. This figure shows far less sea ice compared to the average extent from 1981 to 2010. Meanwhile, 287 times of maritime transits through the Northwest Passage have been made during the 2017 and the first ship traversed the Northern Sea Route without the assistant of ice-breaker in August 2017. Commercialization of the Arctic Passage means significant economic and strategic advantages by shortening the distance. In this article, 'Arctic Passage' means Northern Sea Route along the Arctic coast of Russia and Northwest Passage crossing Canadian Arctic Ocean. As climate changes, the potential feasibility of the Arctic Passage has been drawing international attention. Since navigation in this area remains hazardous in some aspects, IMO adopted Polar Code to promote safe, secure and sustainable shipping through the Arctic Passage. Futhermore, Russia and Canada regulate foreign vessels over the maritime zones with the authority to unilaterally exercise jurisdiction pursuant to the Article 234 of UNCLOS. The dispute over the navigation regime of the arctic passage materialized with Russia proclaimed Dmitrii Laptev and Sannikov Straits as historically belong to U.S.S.R. in the mid 1960s and Canada declared that the waters of the passage are historic internal waters in 1973 for the first time. So as to support their claims, In 1985, Russia and Canada established straight baseline including Northern Sea Route and Northwest Passage. The United States has consistently protested that the Northern Sea Route and Northwest Passage are straits used for international navigation which are subject to the regime of transit passage. Firstly, it seems that Russia and Canada do not meet the basic requirements for acquiring a historic title. Secondly, since the Law of the Sea had adopted before the establishment of straight baseline over the Russian Arctic Archipelago and the Canadian Arctic Archipelago, Ships can exercise at least the right of innocent passage. Lastly, Northern Sea Route and Northwest Passage have fulfilled the both geographical and functional criteria pertaining to the strait used for international navigation under the international law. Especially, should the arctic passage become commercially viable, it can be expected to accumulate the functional criterion. Russia and Canada regulate the ships navigate in their maritime zones by adopting the higher degree of an environmental standard than generally accepted international rules and standard mainly under the Article 234 of UNCLOS. However, the Article 234 must be interpreted restrictively as this contains constraint on the freedom of navigation. Thus, it is reasonable to consider that the Article 234 is limited only to the EEZ of coastal states. Therefore, ships navigating in the Arctic Passage with the legal status of the territorial sea and the international straits under the law of the sea have the right of innocent passage and transit passage as usual.

• Strategy21
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• s.46
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• pp.123-157
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• 2020

This research focuses on one important type of non-traditional threat, maritime piracy, and tries to supplement previous research from the perspective of military power, especially naval power. When considering the elements of military power, naval power is a core independent variable to explain piracy incidents. Indeed, naval power can play a key role in solving piracy problems, since naval power is the only legitimate force to respond to piracy in the sea. It is natural that well equipped and trained naval power in the sea increases the probability of capturing pirates, which leads to increasing the costs of piracy and decreasing its occurrences. In addition, since naval combatant ships have more impressive weapons than those of pirate boats, just the presence of naval combatant ships could serve to deter piracy incidents in the sea. The main purpose of this research is finding the effectiveness of large multinational naval efforts to deter piracy incidents in Africa. With this research purpose, I analyze 771 piracy incidents that occurred in African states from 2009 to 2014. Furthermore, I include all 33 coastal states in Africa regardless of the experiences of piracy incidents in order to avoid selection bias, which is very common in quantitative-based piracy incidents research. The dependent variable of this research is frequency of maritime piracy incidents for a country-year and the independent variable is the number of multi-national naval warships that operate near Somalia. With this analysis, I find the large number of multi-state naval combatant ships are negatively related to piracy incidents. In other words, as a main means to counteract piracy incidents, multi-state naval combatant ships are conducive to reduce piracy incidents near Somalia, since it increases costs (being captured) of conducting piracy.

• The Journal of Fisheries Business Administration
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• v.39 no.2
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• pp.81-108
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• 2008

Since the declaration made by UN Convention on the Law of the Sea on EEZs, The open seas of Northeast Asia, considerd as a convention area, needed new agreements in conformity with the changes brought by the introduction of the Exclusive Economic Zone(EEZ) system. The Contracting Parties of these agreements set up their own EEZs, which extend certain ranges from their baselines, Fishing in the other party's EEZ is done based on mutual agreements, which take into account traditional fishing activity in the zones. Seperate fishries management systems, in accordance with the relevant legal status of the waters, are applied to individual overlapping areas: Middle Zone in the Bast Sea and the waters south of jeju Island, Interim Measure Zone in the Yellow Sea and East China Sea, and the Transitional Zone in the Yellow Sea. They decided to conclude fisheries agreements as the provisional agreement under Article 74(3) of the UN Convention before the delimitations of the EEZs to avoid the territorial disputes. China and Japan concluded the Fishries Agreement in the November 1997, allowing each coastal State 52 mile EEZ. it was followed by Korea and Japan in September 1998, reaching a final compromise. And also Korea and China came to a satisfactary settlement in November 1998. Fisheries agreements have been established between the three North-east Asian States, the agreement are all bilateral. That implies inefficient resource management on the overlapping waters of the three states, especially on the East China Sea. The Korea-Japan Fisheries Agreement and the China-Japan Fishery Agreement worked as governing rules in the North-east Asian seas before the establishment of EEZs (Exclusive Economic Zones). However the conclusion of the bilateral fishery agreements, Korea China and Japan have developed EEZs, and these three countries have competed for the exploitation of fisheries resources. Therefore, the issue of fisheries resource management was no longer a single countries' problem and emerged as a common issue facing these three countries. In recognition of the above-mentioned problem, it is needed for the construction of cooperative System fishery management in the North-east Asian seas. Therefore, cooperative measures should be establishied. The final goal of the construction of fisheries management cooperative system is to establish sustainable fisheries in the North-east Asian seas. However, there is a big difference in fisheries management tools, fishing gear, exploitation rate of species, etc. This implies that a careful approach should be taken in order to achieve the cooperative fisheries management among Korea, China and Japan. conclusionly, the Governments of Korea, China and Japan should complement three bilateral agreemens, and which they prepares to 'Fisheries Resource Restore Program' Between Korea, China and Japan in the adjacent waters south of Jeju Island.

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.1
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• pp.30-43
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• 2003

The geography, circulation pattern, and ecology show that the semi-closed seas of Northwest Pacific be managed as one complete system. Ongoing multilateral cooperative efforts relevant to marine environmental protection in the Northwest Pacific area, include the Working Group for the Western Pacific (WESTPAC) established under the auspices of WNESCO's Intergovernmental Oceanographic Commissions, the UNDP/GEF Programme on Prevention and Management of Marine Pollution in East Asian Seas (PEMSEA), the North Pacific Marine Science Organization(PICES), and the United Nations Environment Programme(WNEP)'s Northwest Pacific Action Plan(NOWPAP). The present report firstly describes the current situations on the existing regional cooperative regimes for marine environmental conservation in the Northwest Pacific region, with a special respect to the Northwest Pacific Action Plan(NOWPAP) which was adopted in 1994 by Japan, People's Republic of China, Republic of Korea and Russian Federation. Then, problems of the existing regimes are also discussed, together with the suggestion of the possible solutions, focusing on NOWPAP. Suggestions include: 1) the Northeast Asian countries should understand the importance of legally-binding regional convention, and should build up any legally-binding instrument which can function as a big umbrella for real regional cooperation without prejudice to the rights of the States, 2) At present stage, it will be possible to make a regional convention flexible without prejudice to the sovereign right of the States or territorial issues; 3) taking into account that the region often faces many generic political problems that often inhibit the effective collective actions on environmental issues, the leadership from UNEP or other international organizations is required; 4) strong institutional and financial framework should be made, and 5) multilateral efforts to respond to the new marine environmental threats should be taken at the regional level in order to protect the coastal and marine environments in the Northwest Pacific.