• 제목/요약/키워드: sea

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Optimal growth conditions and economic analysis of sea cucumber releasing

  • Lee, Cheol;Choi, Sang Duk
    • Fisheries and Aquatic Sciences
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    • 제23권4호
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    • pp.11.1-11.11
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    • 2020
  • We tried to find the optimal growth conditions of sea cucumber and to analyze the economic effectiveness of the sea cucumber seedling release project in Korea. We first examined the optimal growth conditions of sea cucumber in the relating literatures. Then, we analyzed the economic effectiveness of the sea cucumber seedling release project of the Woncheon fishing village union of Gyeongnam Province in 2016-2018 by using the cost benefit analysis method. The net income of the release project of the Woncheon fishing village union was 69,850 Korean won. The benefit to cost ratio of the sea cucumber seedling release project of the Woncheon fishing village union was estimated to be 1.7, indicating that the project was economically feasible. In order to improve the economic feasibility of the sea cucumber release project, as we see in the case of the Woncheon fishing village union, it is necessary to manage the purchase of the sea cucumber seedling, to improve the recapture rate of sea cucumber, and to manage marketing of sea cucumber.

Relationship between Spring Bloom and Sea Ice in the Northern East Sea

  • Park, Kyung-Ae;Choi, Hwa-Jeong
    • 한국지구과학회:학술대회논문집
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    • 한국지구과학회 2010년도 춘계학술발표회 논문집
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    • pp.134-134
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    • 2010
  • Sea ices at the Tatarskiy Straitin the East/Japan Sea appear from November to April. Cold and fresh water, melted from the sea ices, may contain nutrients which are indispensable to spring bloom of phytoplankton and may provide a preferable condition to the spring bloom through changes in vertical structure of water column and stratification. Relation between the spring bloom along the Primorye coast and sea ices in the Tatarskiy Strait were investigated using multi-satellite multi-sensor data; ten-year SeaWiFS chlorophyll-a concentration data and PAR data, sea surface temperatures from NOAA/AVHRR, sea ice concentration and near-surface wind speed data from DMSP/SSMI, near-surface wind vectors from QuikSCAT, and others. We provided evidences of southwestward flowing cold water masses from sea ice and its relation of chlorophyll-a concentration. This study showed that year-to-year variations of chlorophyll-a concentration in spring were positively correlated with those of sea ice concentrations at the Tatarskiy Strait.

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Larval Anisakid Infections in Marine Fish from Three Sea Areas of the Republic of Korea

  • Cho, Shin-Hyeong;Lee, Sang-Eun;Park, Ok-Hee;Na, Byoung-Kuk;Sohn, Woon-Mok
    • Parasites, Hosts and Diseases
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    • 제50권4호
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    • pp.295-299
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    • 2012
  • The present study was performed to determine the infection status of anisakid larvae in marine fish collected from 3 sea areas of the Republic of Korea. Total 86 marine fish (8 species) collected from the East Sea (Goseong-gun, Gangwon-do), 171 fish (10 species) from the South Sea (Sacheon-si, Gyeongsangnam-do), and 92 fish (7 species) from the Yellow Sea (Incheon Metropolitan City) were examined by both naked eyes and artificial digestion method. Among the total of 349 fish examined, 213 (61.0%) were infected with 8 species of anisakid larvae, i.e., Anisakis simplex, 6 types of Contracaecum spp., and Raphidascaris sp., and the mean larval density was 13.8 per infected fish. Anisakid larvae were detected in 45 fish (52.3%) from the East Sea, 131 fish (76.6%) from the South Sea, and 37 fish (40.2%) from the Yellow Sea. The average numbers of larvae detected were 4.0, 16.6, and 15.9, respectively. Anisakis simplex larvae were detected in 149 fish (42.7%), and the mean larval density was 9.0 per infected fish. They were found in 26 fish (30.2%) collected from the East Sea, 96 fish (56.1%) from the South Sea, and 27 fish (29.3%) from the Yellow Sea. The average numbers of larvae detected were 2.9, 10.3, and 10.5, respectively. Conclusively, the present study suggests that the infection rate and density of anisakid larvae are more or less higher in the fish from the South Sea than those from the East Sea or the Yellow Sea.

SeaSign에 대한 효율적인 서명 방법 및 최적 파라미터 제안 연구 (A Study on Efficient Signing Methods and Optimal Parameters Proposal for SeaSign Implementation)

  • 김수리
    • 정보보호학회논문지
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    • 제34권2호
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    • pp.167-177
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    • 2024
  • 본 논문은 isogeny 기반 전자 서명 알고리즘인 SeaSign의 최적화 방안을 제안한다. SeaSign은 CSIDH의 class group action에 Fiat-Shamir with abort를 결합한 전자서명 알고리즘이다. CSIDH 기반 암호는 SIDH 기반 암호가 다항시간안에 공격됨에 따라 다시 주목받고 있지만, 이를 기반한 전자서명인 SeaSign은 비효율적인 속도로 많은 최적화가 진행되지 않았다. 본 논문에서는 SeaSign에 대한 효율적인 서명 방법을 제안한다. 제안하는 서명 방법은 간단하지만 강력하며, 알고리즘 내에서 rejection sampling의 위치 변경을 통해 이루어진다. 추가로, 본 논문에서는 제안하는 알고리즘이 최적 성능을 제공할 수 있는 파라미터를 제시한다. 제시한 결과, 기존 SeaSign의 파라미터를 사용할 경우, 본 논문에서 제안한 서명방법은 기존 SeaSign 대비 3배 빠른 성능을 보인다. 추가로 신규 제시된 파라미터와 본 논문의 서명 방법을 결합한 경우, 기존 SeaSign 대비 290배 빠른 성능과 Decru 등이 제안한 방법 대비 7.47배 빠른 성능을 제공한다.

황해 동부 연안의 홀로세 해수면 변화: 대리기록과 관측자료를 통한 재검토 (Holocene Sea Level Changes in the Eastern Yellow Sea: A Brief Review using Proxy Records and Measurement Data)

  • 이은일;장태수
    • 한국지구과학회지
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    • 제36권6호
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    • pp.520-532
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    • 2015
  • 황해 동부 해안의 홀로세 해수면 변동 특성을 이해하고 시기 별 상승추세를 비교하기 위하여 지질학적 대리기록과 기기관측 자료를 통합하여 분석하였다. 홀로세 동안 황해의 해수면은 초기에 약 10 mm/yr의 속도로 빠르게 상승하고 중기를 거쳐 후기로 갈수록 해수면 상승률은 1 mm/yr 정도로 둔화되며, 20세기 해수면은 홀로세 후기보다 다소 빠르게 상승하였다. 빠른 상승으로 알려진 현재 해수면 상승률은 홀로세 초기와 중기의 상승추세와 비교할 때 사실 훨씬 낮거나 비슷하게 나타난다. 최근 조위계 자료는 황해 해수면이 21세기로 갈수록 상승률이 높아지고 있음을 나타낸다. 이러한 상승 추세는 전 지구적 해수면 변화와 일치한다. 추가적으로, 연구지역에서 현재의 해수면 상승 추세는 이산화탄소 농도와 해수표층온도의 증가율과 대비되며, 이는 인간활동에 수반된 지구온난화의 신호이다. 그러므로 황해 동부와 전세계의 해양에서 관찰되는 현 지구온난화에 의해 야기된 해수면 변화를 '인류세' 해수면 변화라고 제안한다. 이 해수면변화는 조위계와 인공위성 고도계 같은 기기관측을 기반으로 하며, 계측시대를 의미한다. 이와 같이, 황해의 홀로세 해수면 변동은 대리기록으로, '인류세' 해수면은 기기관측을 기반으로 한다.

First detailed morphological description of the loggerhead sea turtle (Caretta caretta) caught from the Yellow Sea of Korea

  • Lee, Heon-Joo;Kim, Il-Hun;Kim, Ja-Kyeong;Jeong, Sumin;Park, Daesik
    • Journal of Ecology and Environment
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    • 제37권4호
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    • pp.201-208
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    • 2014
  • To date, no study has reported detailed morphological characteristics of Korean sea turtles. Due to the lack of such basic information on Korean sea turtles, further related studies have been difficult in South Korea. In this report, we determined the species and the sex of the one sea turtle caught from the Yellow Sea of Korea (Taean-gun, Chungcheongnamdo) on July 17, 2013, and described its detailed morphological characteristics. The sea turtle was identified as a loggerhead sea turtle (Caretta caretta) by the presence of an interprefrontal scale on the head. The turtle had three times longer length between the edge of anal scute to the anus than that between the anus to tip of the tail, and the size of a pair of claws on the flippers were distinctively different, suggesting that the turtle was a male. Finally, the assumption that the sea turtle might be sexually mature is based on its body weight (59.95 kg), the maximum straight length of the carapace (72.5 cm), and the worn serrated parts at the edge of supracaudal scutes. The loggerhead sea turtle described in this study is the first record from the Yellow Sea of Korea.

명치시대(明治時代) 일본의 조선(朝鮮) 바다 조사 (On the Japanese Investigations for the Korean Sea during Meiji Period)

  • 이근우
    • 수산경영론집
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    • 제43권3호
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    • pp.1-22
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    • 2012
  • This study is to survey the Japanese investigations for Korean sea during Meiji period. Meiji government was eager to develop new fishing ground to provide the marine products to their people, to offer the job for their people and to accumulate the starting capital. They found that the Korean sea was abundant in shark, sea cucumber and ear shell. These products were valuable for Chinese foods. From 1870's, Japan Navy investigated Korean sea for military purpose and subsequently for fishery. The first investigation for Korean maritime products was The Circumstances for Catching Fish in Korean Sea by Sekizawa Akikiyo in 1893. He was the most famous specialist in fishery and insisted that Japanese fishermen must go to Korean sea and catch fishes. Meiji government accepted his opinion and pushed the policy sending fishermen to Korean sea. Meiji government enlarged the investigations and backed up the activities of fisherman and the organization for fishery in Korean sea. Especially, the investigations by The Association for Korean Sea Fishery were repeated and detailed(1897~1900). The Association intervened the conflicts between Korean and Japanese fishermen. At the same time, The Association investigated the attitudes of Korean people to Japanese. The Guidelines for Fishery in Korean Sea by Kuzuu Syuzo was also very detail, especially in the kinds of fishes in Korean sea. These investigations were supported by Meiji government or organizations helped by government.

연안도시지역 해풍지연이 오존분포에 미치는 영향 (Effects of Late Sea-breeze on Ozone Distributions in the Coastal Urban Area)

  • 오인보;김유근;황미경
    • 한국대기환경학회지
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    • 제20권3호
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    • pp.345-360
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    • 2004
  • The late sea-breeze and its impacts on ozone distributions were investigated during April to September from 1998 to 2002, in the Busan metropolitan area (including surrounding areas) using the surface ozone concentrations (obtained at 9 monitoring sites), local meteorological variables (obtained near the shore), together with synoptic data. The urban scale ozone concentration was also simulated using the MM5/UAM-V to better understand the role of late sea-breeze in Busan. The results from observation study showed that most of the late sea-breeze occurred when weak offshore synoptic flow (northwesterly) suppressed development of sea - breeze, and the ozone concentration level and frequencies exceeding ozone standard increased with the onset time of sea breeze. We also found that the late sea-breeze clearly induces relatively weak wind speed and high temperature during the daytime As a result it enhances the photochemical ozone accumulation and delays the occurrence time of the averaged maximum ozone concentrations. The results of simulation for high ozone episode (24 August, 2001) by MM5/UAM -V revealed that the late sea-breeze interacted with weak offshore synoptic wind can contribute significantly to high ozone concentration in the coastal urban area. The simulated horizontal and vertical distribution of ozone concentration indicated that ozone can be accumulated over the sea under stagnant condition and return to the land in the late afternoon with the sea breeze, suggesting both the relationship between late sea-breeze and recirculation and the importance of late sea -breeze effects influencing severe ozone pollution in Busan.