• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.3
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• pp.137-145
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• 2004

Long-term wave distribution at Jeju sea is investigated by a numerical simulation based on the thirdgeneration wave model SWAN (Simulating WAves Nearshore). The Jeju sea which retains relatively high wave energy density among Korean coastal regions is considered to be a suitable site for wave power generation and the efficiency of wave power generation is closely related to local wave characteristics. The monthly mean of a large-scale long-term wave data from 1979 to 2002, which is provided by Korea Ocean Research & Development Institute. is used as the boundary condition of SWAN model simulation with 1km grid. An analysis of wave distribution concentrates on the seasonal variation and spatial distribution of significant wave heights, mean wave directions and mean wave periods. Significant wave heights are higher in winter and summer and the west sea of Jeju appears relatively higher than east's. The highest significant wave height occurs at the northeast sea in winter and the second highest significant wave height appears at the southeast sea in summer, while the significant wave heights in spring and autumn are relatively low but homogeneous. The distribution of wave directions reveals that except the rear region influenced by wave refraction, the northwest wave direction is dominant in summer and the southeast in winter. Wave periods are longer in summer and winter and the west sea of Jeju appears relatively longer than east's. The longest wave period occurs at the west sea in winter, and in summer it appears relatively homogeneous with a little longer period at the south sea.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.4
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• pp.227-231
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• 2008

The purpose of this study is to clarify the behavior of stranded crude oil and to estimate the restoration of seawater infiltration by application of dispersant as one of cleaning techniques. We made visualization of infiltration process of seawater and stranded crude oil on the sandy beach sediments by using of a model sandy beach. Major conclusions derived from this study are as follows. The seawater infiltration volume was reduced by the stranded crude oil. However, thirty percentage of the sweater infiltration into the sediments was restored by dispersant application to the penetrated oil in sandy beach. The penetration depth of stranded oil were dropped at first falling tide, but were not significantly fluctuated after that. Moreover, oil concentration was most high within the upper 2 cm. The stranded crude oil was broken into small size droplets and dispersed into the sediments by the dispersant application. Therefore, dispersant applications play an important roles in the large increase of surface area of given volume of oil, and it resulted in promoting to biological degradation process at the oil/water interface, dispersing the stranded oil into the water column and restoration of the supplement of the dissolved oxygen and nutrients to the benthic organisms.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.4
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• pp.310-321
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• 2016

This study describes the spatial distribution of dinoflagellate cyst assemblages from the fishing ports along Jeju Island. Surface sediment samples from 22 stations revealed the occurrence of 29 species involving the Groups Protoperidinioid (44.8%), Gonyaulacoid (31.0%), Calciodineloid (10.3%), Gymnodinioid (6.9%), Diplosalid (3.5%) and Tuberculodinioid (3.5%). The cyst abundance recorded here is very low ($13{\sim}220cysts\;g-dry^{-1}$) as compared to Korean coastal regions. The abundance of heterothophic cysts increased in several fishing pots with fine sediments and anthropogenic tidal pools. And cyst abundance was well correlated with the grain-size composition of surface sediments. The dinoflagellate cyst assemblages in Jeju fishing ports were characterized by the dominant species, cyst of Gymnodinium sp., cyst of Pyrodinium bahamense and cyst of Scrippsiella trochoidea in 2012, Protoperidinium sp. (Brigantedinium sp.), cyst of Scrippsiella sp./trochoidea and cyst of Gymnodinium sp. in 2014, and Protoperidinium sp. (Echinidinium sp. and Brigantedinium sp.) in 2016. The advent of the toxic dinoflagellate, Pyrodinium bahamense were recorded for the first time in Jeju coastal waters. As a results, we are determined should be to monitoring and management measures for new toxic dinoflegallates from tropical or subtropical reigions and anthropogenic tidal pools by industrial activities.

• The Korean Journal of Pesticide Science
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• v.4 no.1
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• pp.19-25
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• 2000

The adsorption and leaching of organophosphorus pesticide, EPN (O-ethyl-O-4 -nitrophenyl phenyl phosphonothioate) were investigated in Namwon soil(black volcanic soil), Aewol soil(very dark brown volcanic soil) and Mureung soil(dark brown nonvolcanic soil) in Cheju Island. The residue of EPN was surveyed on coastal environment of Cheju in Aug. 1996. The organic matter of Namwon soil, Aewol soil and Mureung soil was 19.8, 6.2 and 2.4%, respectively. The cation exchange capacity of Namwon soil, Aewol soil and Mureung soil was 24.8, 13.0 and 9.5 meq/100 g, respectively. The Freundlich constant, k value, was 89.4, 26.9 and 9.25 for Namwon soil, Aewol soil and Mureung soil, respectively. The k value of Namwon soil with very high organic matter content and cation exchange capacity was the highest for Aewol soil and Mureung soil. The Freundlich constant, 1/n, show a high correlation with organic matter content, i.e. it is less than unity for organic matter rich soil of Namwon soil and greater than unity for organic matter poor soil of Mureung soil. The leaching of EPN was slower for Namwon soil with high k values, and faster for Mureung soil with low k values. The results of the study was demonstrated the potential of pollution for EPN have little leached into soil environment. EPN was not detected in seawater and sediment in the coastal environment in Cheju Island. EPN used in the farm on tile Cheju island were not residued in the coastal environment.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2003.11a
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• pp.91-97
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• 2003

본 연구는 온라인 게임공간에서 게이머들이 어떻게 서로 다른 가치관과 행동 패턴을 드러내는지를 확인하고 이를 통해 온라인 게임세계의 문화를 이해하고 분석하기 위해 실시되었다. 전 세계에서 가장 많은 게이머들이 활동하고 있고, 한국과 일본에서 동시에 서비스되고 있는 온라인 게임인 〈리니지〉의 게이머들을 대상으로 온라인 설문조사를 실시하여 '라이프 스타일' 분석틀을 이용해서 이들이 게임공간에서 보이는 행동을 분류하였다. 글 결과 한국과 일본의 리니지 사용자들에게서 거의 유사한 세 가지 라이프스타일 패턴이 추출되었으며 한국과 일본에서 라이프스타일에 따른 행동 패턴이 일관적으로 나타나고 있음을 확인하였다. 도한 한국과 일본의 문화적 차이는 각 라이프스타일 프로파일의 극단성과 분포비율에 의해 반영되는 것으로 확인되었다. 일본의 탈사회적 게이머는 한국의 그것에 비해 더 극단적인 반면 전체 응답자 중에서 차지하는 비율이 적었고 게임 세계에서의 사회 경제적 위치도 낮았으며 한국에서는 비교적 적은 비율을 차지하던 싱글 플레이어 유형이 일본에서는 가장 많은 비중을 차지하는 것으로 나타났다. 또한 일본의 게이머들은 라이프스타일에 상관없이 대부분이 게임 공동체에 가입하는 반면 한국의 게이머들은 라이프스타일에 따라 공동체 참여율이 달랐지만 전체적인 참여율은 일본에 비해 높았다. 이러한 차이는 일본 게임세계에서 공동체 참여는 기본적인 의무인 반면 한국에서는 현실적인 이익과 직결된 활동임을 시사한다. 또한 게임몰입수준은 한국보다 일본의 리니지 게이머들이 높았다. 아시아 각 국에 한국에서 개발한 동일한 온라인 게임이 확산되어 있는 현황을 고려할 때, 온라인 게이머의 라이프스타일 척도는 한국과 일본뿐만 아니라 대만과 중국, 홍콩, 그리고 미국과 같은 리니지 게임이 서비스되는 모든 국가의 문화적 차이를 이해하고 과학적으로 분석할 수 있는 방법이 될 수 있을 것으로 기대된다. 의미를 되새기는 것으로 짧은 연구를 시작하겠다. 등은 활성 값이 70% 이상으로 퇴적물 독성이 상대적으로 낮았다. 이중나선 DNA 함량은 28.4 % - 49%로 대조군에 비해서 감소가 크다. 대부분의 정점이 대조군의 30% 내외로 정점 간의 차이는 크지는 않다. 그러나 다른 측정자료와 같이 정점 22에서 18%로 최소치를 나타내고, 정점 2, 12에서 20% 내외의 값을 보인다. 종합적으로 볼 때 오염물질의 유입이 크고, 광양제철 인근 정점 들이 모두 다른 정점에 비해서 낮아서, 퇴적물 독성이 높은 정점으로 조사되었다.hiwo의 광합성 능력은 낮은 농도들에서는 대조구와 유사하였으나, 5 $\mu\textrm{g}$/l의 높은 농도에서는 초기에 매우 낮은 광합성 능력을 보이다가 시간이 경과하면서 대조군보다 더 높은 경향을 나타냈다. 이러한 결과는 식물플랑크톤이 benso[a]pyrene의 낮은 농도에서 노출될 때는 이 물질을 탄소원으로 사용할 가능성이 있음을 시사한다. 본 연구의 결과들은 연안해역에 benso[a]pyrene과 같은 지속성 유기오염물질이 유입되었을 때 내정여부에 따라 식물플랑크톤 군집내 종 천이와 일차생산력에 크게 영향을 미칠 수 있음을 시사한다.TEX>5.2개)였으며, 등급별 회수율은 각각 GI(8.5%), GII(13.4%), GIII(43.9%), GIV(34.2%)로 나타났다.ments of that period left both in Japan and Korea. "Hyojedo" in Korea is supposed to have been influenced by the letter design. Asite- is also considered to have been "Japanese Letter Jobcheso." Therefore, the purpose of this study is to look into

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.1
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• pp.54-62
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• 1995

In order to telemeter the behavior and distribution of fishes. the telesounder was manufactured and it was examined to verify its performance and effects in the gape nets with wings located around Gokunsan islands. Yellow Sea. on August 8. 18~19 and September 8~9, 1994. The behavior of fish entering the net was observed with the buoy station at sea which was installed at the entrance of the gape nets with wing and its echosignal was transmitted remotely to the base station on ship at distance of about 1 km away from the buoy station at sea. The fishes catched by the gape nets with wings were 12 species and Anchovy(Engraulis japonica), Beka squid(Loligo beka), Herring(Harengula zunasi) was 95% of total catches. The images of color display monitor at the base station on ship were very well coincident with the records of fish finder from the buoy station located at sea. When the current velocity was less than 0.6 kt and slight fluctuation, the fishes entered into the gape net were much more in comparision with over 1.0kt and heavy fluctuation, and then the average swimming depth was about 4 m. The catches per one hauling was about 10~30 kg and when the current velocity was too weak and the current direction did not coincident with the direction of net or the current velocity was too strong, the catches was a few. It is concluded that telesounder system is very useful for investigating the distribution and the swimming behavior of fishes entering in the gape nets with wings.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.3
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• pp.189-195
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• 2001

The characteristics of echolocation signals of the Common Dolphin, Delphinus Delphis was observed by the hydrophone in order to detect exactly distribution and migration on whales and dolphins in Korean Coastal waters. It's observation was carried out at the position of 13 mm off Gam-Po of Korean east-southern sea at 3rd-5th. April and 13th-15th. October, 1999. The results obtained are summarized as follows: (1) The frequency range of ship's noise and ambient noise in the observed station was 0.5-0.3 kHz, that ones could be influenced to the behavior of common dolphins which carry out echolocation using low-frequency. (2) The common dolphin was radiated single click of 8.6 ms and double click of 4.8 ms pulse width during these observation (3) The high click frequencies of common dolphin were 5.10 kHz, 7.22 kHz, 10.60 kHz with the click pulse width of 4.0 ms, 2.6 ms, 1.0 ms, respectively. In case of low-frequency 1-2 kHz, that is, 1.12 kHz, 1.38 kHz, 1.82 kHz, pulse width were 22.4 ms, 2.05 ms, 11.9 ms, respectively and they showed a tendency using triple click signal. (4) The pulse width, pulse recurrence interval and frequency range of the observed echolocation signals were 2.4-8.4 ms, 9.0-40.0 ms, 0.60-10.63 kHz respectively, and frequency spectrum level was 100-125 dB for single, double, triple click signals.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.3
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• pp.241-248
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• 2002

The combined hydroacoustic and demersal trawl surveys to investigate the distribution characteristics of fish schools in the Yellow Sea and the East China Sea were carried out during the spring of 1997 by the training ship "Nagasaki Maru" of Nagasaki University. Fish samples were collected by bottom trawling from 9 trawl stations randomly selected in the survey area, and the species and length compositions of trawl catches are examined. Hydroacoustic data were collected by using a Furuno FQ-50 scientific echo sounder operating at 50KHz and the data stored in field were later processed in the laboratory. The results obtained can be summarized as follows ：1. In the 9 trawl surveys conducted in the Yellow Sea and the East China Sea, 78 species including 80 species of fishes, 4 species of Cephalopoda and 6 species of Crustacea, were identified. The most abundant species in these stations were swimming crab(Portunus trituberculatus), Japanese horse mackere(Trachurus japonicus), redlip croaker(Larimichthys polyactis) and the catch per one hour in each station ranged 7.7 to 182.5 kg/hour. 2. The mean volume backscattering strength for the entire water column and the bottom layer of the 0-10 m from bottom friction were -74.6 ㏈ and -68.2 ㏈, respectively. That is, the mean volume backscattering strength for the bottom layer was 6.4 ㏈ higher than that for the entire water column 3. In the surveys during the spring of 1997, the geographical distribution characteristics of fish schools suggests a trend of decreasing fish abundance toward the coast area of Korea and the highest demersal concentrations appeared in waters between the Cheju Island and the Tsushima Island 4. The distribution density of fish school in the East China Sea and Yellow Sea during the 1997 acoustic survey were estimated to be 6.65$\times$10$^{-5}$ kg/㎥ in the entire water column and 2.86$\times$l0$^{-4}$ kg/㎥ in the bottom layer, respectively.pectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.3
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• pp.202-208
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• 2002

Test fishing was carried out utilizing a coastal pot-fishing boat from IS March to 7 April 2002 and the results obtained are summarized as follows ; 1. Mean catches(Number of sea eels) according to the soak time of 3 hours, 6 hours and 12 hours were 44.6, 60.0 and 83.3, and CPUE(Number of catch / 10pots·hour) were 2.5, 1.7 and 1.1 respectively 2. Catch difference between over 24 hours and 48 hours was 11.3% and 3.3% between over 48 hours and 72 hours. 3. In the test fishing, by-catches were so low(1.5∼3%) until 12 hours of soaking time passed By-catches were increased according to the soaking time addition on the over 24 hours of soaking time. The bait effect for sea-eel seems to be diminished as soon as the casting started and there was big difference in proportion to bait size and freshness.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.2
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• pp.140-148
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• 2002

The primary goal of this study is to determine the distribution characteristics using a scientific echo sounder in the Yellow Sea west of South Korea. The survey was carried out between 33$^{\circ}$00'N~37$^{\circ}$00'N latitude and 124$^{\circ}$00'E~126$^{\circ}$00'E longitude during the months of May and August, 1999 and April, 2000. The ships used in this survey were the R/V Chung-kyeong(G/T 300) and R/V Dong-baek(G/T 1,050) of Yeosu National University. The results obtained are as follows : 1. From the oceanographic data the Yellow Sea were divided into three sea areas which were the western waters of Chejudo, Mokpo and Kunsan. The oceanographic conditions were different in each of these three areas and the western waters of Chejudo were higher about 1~5$^{\circ}C$ more than the western waters of Gunsan. Generally, thermoclines were presented clearly in all three areas, but more so in August than in May according to seasons. 2. The horizontal distribution of S$_{A}$(area backscattering coefficient per unit area) value is that the western sea waters of Chejudo area are higher than that of the western sea waters of Mokpo and Gunsan. 3. The vortical distribution of S$_{A}$ value varies with thermocline that the harder thermocline is, the higher the S$_{A}$ value is. 4. The S$_{A}$ values on the types of biomass distribution are different with frequency. At the 38kHz, the demersal schools have higher values than the pelagic schools. At the 120kHz, the pelagic schools have higher values than the demersal schools.