• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.7
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• pp.893-901
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• 2017

In order to understand the fluctuation characteristics of water temperature in August, water temperature, tide level, air temperature and wind data were analyzed using a power spectrum and coherence analysis for a region off the southern coast of Korea. Spectrum analysis showed that the water temperature and tide level in Wando, Goheung, Yeosu, Tongyeong and Masan have peaks over a semi-diurnal period. Coherence showed that water temperature was affected by tide in Wando, Goheung, Yeosu and Tongyeong where tidal range is relatively high. In Masan and Busan, where tidal range is relatively low, however, the tide did not affect water temperature significantly. In particular, wind was the most important factor in relation to water temperature in Masan. Time lags were calculated from phase. In Wando, water temperature decreased 1.5 hrs after a flood tide began. Water temperature decreased 0.3 hrs after a flood tide began in Goheung and Tongyeong. In Masan, water temperature increased 3 hrs after a south wind began. Water temperature in Yeosu was affected by tide, but air temperature, tide and wind in Busan affected water temperature very little.

• Convergence Security Journal
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• v.18 no.3
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• pp.105-112
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• 2018

South Korea and Vietnam have been engaged in extensive political, economic and cultural exchanges since the establishment of diplomaticties in 1992. In March 2018, Moon Jae-in, President of South Korea, made an official visit to Vietnam, a key partner of the New Southern Policy and discussed comprehensive cooperation measures, including expanding trade volume and measures to establish peace on the Korean Peninsula. At the defense ministers' meeting held in April 2018, the two countries signed a joint defense and defense cooperation statement, which included promotion of maritime security, defense cooperation, UN PKO activities, excavation of remains, and joint military cooperation. Currently, Vietnam is facing territorial disputes with China over the South China Sea, and is stepping up military modernization and military buildup to counter this. In particular, Vietnam is strengthening its external military cooperation beyond ideology with the U.S., Russia, India and France to strengthen its maritime power. Against this backdrop, the bilateral cooperation between South Korea and Vietnam needs to expand beyond the traditional economic and cultural exchanges to military cooperation. The study aims to review the relationship between South Korea and Vietnam on the 26th anniversary of the normalization of diplomaticties and seek ways to develop military cooperation with Vietnam, which has grown to the next China. To that end, it analyzed Vietnam's security environment and military strategy and presented strategies for promoting military cooperation focusing on defense areas.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.3
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• pp.133-139
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• 2010

Marine algal flora and community structure were investigated at four sites in Kijang area on the southern east coast of Korea in August 2006 and August 2009, respectively. A total of 54 seaweeds including 6 green, 10 brown, 38 red were collected and identified. Of 54 seaweeds, 35 species were found throughout the survey period. Mean biomass in wet weight was from $616.0\;g\;m^{-2}$ to $1,462.4\;g\;m^{-2}$2 in 2006, and $354.8\;g\;m^{-2}$ to $965.6\;g\;m^{-2}$ in 2009. Maximum biomass was recorded at Mundong site, and minimum was recorded at Seoam (2006) and Dongbaek (2009) sites. The flora investigated (2006, 2009) could be classified into six functional groups such as coarsely branched form (58.7%, 58.1%), thick leathery form (10.9%, 11.6%), filamentous form (13.0%, 9.3%), crustose form (6.5%, 9.3%), sheet form (6.5%, 7.0%) and jointed calcareous form (4.3%, 4.7%) during survey period. The R/P, C/P and (R+C)/P values reflecting flora characteristics were 4.00, 0.75 and 4.75 at 2006, and 5.17, 1.00 and 6.17 at 2009, respectively. Therefore, the number of marine algae species and biomass in Kijang area were similar when they were comparing with the previous data. It suggest that any changes of seaweed diversity have not been observed in Kijang coastal area before and after the anthropogenic construction between 2006 and 2009.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.3
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• pp.219-224
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• 2007

Two monitoring buoys equipped with ADCP were deployed at the deepest positions along the trough of the central Gwangyang Bay in spring 2006 in order to study the circulation in the bay. Northward velocity is commonly dominant at both stations located in the eastern part of the channel, which supports the cyclonic circulation accompanied by the southward flow in the western part. The southern station has a distinct two-layer structure with current reversal at 14 m depth and increasing northward velocity in the lower layer to 36 m depth close to the bottom. At the northern station the northward flow becomes accelerated due to the decrease in the cross-sectional area and this northward current is dominant even in the upper layer. In the modal structure from the EOF analysis, the first mode has 74% of total variance at the northern station whereas it is 67% but the baroclinic portion increases at the southern station. The typical northward velocity is about 10 cm/s which is associated with the cyclonic circulation. Subtidal variability due to the local wind effect is negligible, but the nonlocal response associated with offshore Ekman flux by the zonal wind is found during strong wind events.

• Geophysics and Geophysical Exploration
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• v.11 no.4
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• pp.279-285
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• 2008

Korea Institute of Geoscience & Mineral Resources (KIGAM) carried out 2 dimensional multi-channel seismic surveys for Domi-Basin of east-southern part of Jeju Island, South Sea, Korea in 2007. The purpose of this survey is to investigate the structure of acoustic basement and the potential of energy resources in the Korean shelf. It is essential to produce fine stack and migration section to understand the structure of basement. However a basement can not be clearly defined where multiples exist between sea surface and seafloor. This study aimed at designing the optimal data processing parameter, especially to eliminate the peg-leg multiples. Main data processing procedure is composed of minimum phase predictive deconvolution, velocity analysis and Radon filter. We tested the efficiency of processing parameter from stack sections of each step. Our results confirmed that processing parameters are suitable for the seismic data of Domi-Basin.

• Korean Journal of Environmental Biology
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• v.35 no.3
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• pp.361-372
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• 2017

This study described the spatial distribution of dinoflagellate cyst assemblages in the Ulsan Coastal Waters (UCW). Surface sediment samples from 15 stations revealed the occurrence of 33 species involving the Groups Protoperidinioid (51.5%), Gonyaulacoid (30.4%), Calciodineloid (9.1%), Gymnodinioid (3.0%), Diplopsallid (3.0%) and Tuberculodinioid (3.0%). The recorded cyst abundance in the UCW recorded was low ($260{\sim}1,680cysts\;g-dry^{-1}$) compared to Korean coastal waters. The abundance of heterotrophic cysts is higher in the Ulsan harbour and northwestern parts of UCW with eutrophic areas, however autotrophic species are more prevalent in the southern parts with open sea environments. The dinoflagellate cyst assemblages in the UCW were characterized by the dominance of Gonyaulax scrippsae, Protoperidinium sp. (Brigantedinium sp.), and Gonyaulax spinifera complex. The advent of the toxic dinoflagellate, Pyrodinium bahamense var. bahamense was recorded for the first time in the East-south sea of Korea. Therefore, as a result of ongoing monitoring and management for new toxic dinoflegallates from tropical or subtropical regions, analysis of dinoflagellate cyst assemblages in the UCW has been deemed necessary.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.1
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• pp.69-74
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• 2016

Bathymetric changes were studied in the southern sea off the Jinwoo-do Island, which is one of the deltaic barrier islands surrounding the Nakddong river estuary. In this study, 16 bathymetry data sets were obtained from June 2006 to April 2015. Two narrow channels, the one lying between Jinwoo-do and Shinja-do, and the other one lying between Nulcha-do and Jinwoo-do extended into the eastern and western parts of the study area, respectively. The eastern extension of the channel contained a passage of mixed estuarine waters of seawater and river water discharged from the Nakdong river barrier and the west Nakdong River. The western channel connected the Nakdong River estuary with the Busan New Port via a connecting pier. Total volumetric changes of sediments in study area and discharge flow of the Nakdong river barrier were analyzed. Bottom topographical changes occurred mainly in the eastern extension of the channel. These changes were initially characterized by gradual erosion or deposition followed by rapid restoration. The total volume of sediment gradually increased from June 2006 to March 2013, but experienced a sudden decrease in October 2013 because of typhoon Danas. Few fluctuations were observed from October 2013 to April 2015. Analysis of the cross-sectional bathymetry of the north-south direction showed that the deepest point of the eastern channel moved 100-130 m westward and 200 m northward between June 2006 and April 2015.

• The Journal of Fisheries Business Administration
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• v.39 no.1
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• pp.87-114
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• 2008

The cultured tuna production which has suddenly expanded at the short time and the demand for it attract attention. Farming mode, distribution transactions, change of the market (domestic and international) and the price trend are reviewed from the Japan's position which is the biggest consuming country. This paper tries to describe the current status of the food system related to the cultured tuna. Japanese government began the development of the tuna culture technology in 1970. It was by the Fisheries Agency's project. Kinki University which is the large scale private university in Japan participated in the project. After that, 32 years have passed. Kinki University established the full farming of the bluefin tuna in August, 2002. On the other hand, in 1974, one Japanese private enterprise began its tuna farming business in Canada. Kinki University gave this company technical cooperation. Also, in the early stages of the 90s, as for the policy of the overseas fishery cooperation foundation, it supported the tuna farming business in Australia. It is very clear to understand that the long-term technological-development has supported the take-off scene of the tuna culture business not only in foreign countries but also in Japan. The total shipment scale of the cultured tuna expanded very much within about 10 recent years. However, the decrease of the wild tuna catch, the reinforcement of the fisheries regulation and the tuna body to dwarf are remarkable now. Under the condition as the mentioned above, Japan's tuna consumption, especially, in the market at the fatty meat of tuna of the cultured tuna is building up firm status. At present, the Mediterranean Sea coastal countries, Australia, Mexico and Japan have the tuna farming sites. Australia farms the southern bluefin tuna. The others do the bluefin tuna. About for 3 years, Japan farms the juvenile of the tuna. The global production areas are as follows. 8 coastal countries of the Mediterranean Sea; 18,000 tons (61 % of the cultured tuna quantity in foreign countries), Mexico; 4,500 ton (15%), Australia; 7,000 tons (24%). In 2003, Japan has 32 managements and 39 offices for tuna farming. In Japan, Kyushu and Okinawa district, the share shows itself as 80 % of the domestic production quantity. Especially, the share of Amami-oshima Island in Kagoshima Prefecture exceeds 60 %. Therefore, this island has the maximum production scale of Japan. The amount of supply of BT and SBT was 56,000 tons in 2004. In Abroad, the tuna farming business forms a fixed connection between the importer and the wholesaler which have their office in Japan. In the field of the capital composition, the payment in advance, transaction and the way of settlement, each maintains their fixed relation. The market conditions of the cultured tuna are supported by "the decline of price level" and "the expansion of the general public consumption segment". These lead a team merchandising, and it is supported by the fixed business connection of each. This makes the profit of each business which are on the cultured tuna distribution. However, they have competition on the power balance among them.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.1
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• pp.17-24
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• 2009

This study was conducted to find out the effects of relationship between ocean-meteorological factors and snowfall at Incheon, Gunsan and Mokpo when cold and dry continental air mass passed through the West Sea of Korea in winter. Mean snowfall from December to February showed the order of Gunsan (12.7 cm), Mokpo (9.0 cm) and Incheon (7.8 cm). In particular, the snowfall in the three regions showed the regional difference in December and February. It was well consistent with the extension of continental high. Extension of continental high can cause effect on snowfall at the west regions (Inchoen, Gunsan, Mokpo) of the Korean Peninsula. The continental high extended from the southern China to western coastal region of the Korean Peninsula in December, it extended from the northern China to central area of the Korean Peninsula in January. It also extended from the north side of China through Bohai Sea and Yodong Peninsula to central area of the Korean Peninsula in February. Therefore, more snowfall recorded in Incheon is higher in February than December whereas Gunsan and Mokpo is the opposite. The heavy snowfall at the three regions was caused by loss of the heat from the ocean to air when the heat loss was higher than 100 $W/m^2$. The heavy snowfall was also observed when the arrangement of continental high atmospheric pressure and low pressure was high at the west and low at the east, which formed a front in West and when the wind blow from the North or North West at the speed of 4${\sim}$8 m/sec.

• Proceedings of the KSRS Conference
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• v.1
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• pp.174-179
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• 2006

Information on the distribution characteristics of tuna resources in Kiribati EEZ waters in three zones (Zone 1: west Gilbert region, Zone 2: central Phoenix region, and Zone 3: east Line region) as well as their relationship with the ocean environment is critical for sustainable managing the migratory tuna resource and fishing practices in this region. Therefore, this study is designed to investigate the spatial and temporal distribution and concentration of bigeye (BET) and yellowfin tuna (YFT) in Kiribati EEZ waters in relation to sea surface temperature (SST) and thermocline depth so as to better understand the tuna resources management basis in Kiribati waters. The geographic and temporal distribution and concentration were first displayed. Paired t-test was utilized to compare the distribution between the two tuna species based on Catch per Unit Effort (CPUE) derived from the Korean longliners during 1996 to 2004, and also among the three zones of Kiribati EEZ waters. Environmental conditions of the three zones were then compared and correlated with the CPUE of YFT and BET. In addition, the effect of ENSO phenomena on the environmental conditions and the distribution of YFT and BET within the three zones were also examined. The BET was relatively higher in the Zone 3 whereas YFT predominate in the Zone 1 and the Zone 2 due to oceanographic differences among the three zones and the ecological habitats of the two tuna species. It was suggested that El Ni?o/Southern Oscillation (ENSO) phenomena altered the oceanographic conditions of the three zones that in turn change the distribution of the two tuna species. During El Ni?o, the warm phase of ENSO, resulted in having more BET in all the three zones and the opposite observed during La Ni?a (cold phase) replacing by having relatively higher catch rate for YFT, particularly in the Zone 2. Although the results of the study are from short periods (1996 to 2004) in considering oceanographic anomality, these environmental variations should be considered into sustainable fisheries management of tuna fisheries in Kiribati EEZ waters.