• Korean Journal of Environmental Biology
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• v.36 no.2
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• pp.217-231
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• 2018

Planktonic ciliates play an important role in the food web of marine ecosystem as well as a bio-indicator for invasive species from ballast waters or from changing flow of ocean currents due to climate changes. This study was carried out to find some evidences for introduction of such invasive species using ciliate plankton in four major international ports of Korea. We surveyed the seasonal species composition of planktonic ciliate to find out the evidence for the invasive species at Busan, Ulsan, Gwangyang and Incheon ports from February 2007 to November 2008. A total of 45 ciliates species, belonging to 15 genera, were identified during the study period: 33 species occurred at Busan, 31 at Gwangyang, 30 at Ulsan, 18 at Incheon. The abundance of naked ciliates ranged from 566 to $65,151cells\;L^{-1}$ and that of tintinnids 10 to $5,973cells\;L^{-1}$. Based on vector species of ciliates reported from Coos Bay in Oregon, 13 vector species of tinitinnids were identified as follows, Eutintinnus lususundae, E. tubulosus, Favella ehrenbergii, F. taraikaensis, Helicostomella subulata, Stenosemella nivalis, Tintinnopsis ampla, T. beroidea, T. cylindrica, T. directa, T. lohmanni, T. radix, T. rapa. All vector species occurred at Gwangyang port. Most tintinnids were mainly neritic species throughout the survey, while warm water species occurred only in short period at Busan, Ulsan and Gwangyang ports that might be affected seasonally by Tsushima warm current.

• The Science & Technology
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• no.2 s.405
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• pp.8-9
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• 2003

외계생명체 유입설 증거 발견/ 오래된 종이 보관법 개발/ 우리 은하계 주변에 반지 모양의 성운/ 냄새 맡는 폭발물 탐지 장치 개발/ 해왕성에서 위성 3개 새로 발견/ 지구 생물종 목록 25년 내 완성/ 아인슈타인 가설, 사실로 확인 / 멍게 유전자 지도 완성

• Proceedings of the Malacological Society of Korea Conference
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• 2000.11a
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• pp.8-8
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• 2000

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.1
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• pp.36-40
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• 2010

Ballast water has been known as a major vector for global dispersal of toxic dinoflagellates and other microalgae. In this study, biodiversity in ships’ ballast water was examined using a dinoflagellate-oriented PCR primer set and species-specific real-time PCR. While motile dinoflagellates could be observe at very low cell densities by light microscopy,a wide range of dinoflagellate taxa including parasitic and phototrophic pico-dinoflagellates as well as harmful species to marine fish/shellfish was detected when techniques for cloning/sequencing of SSU rDNA of sample cells were used. Present result suggests that molecular methods including species-specific PCR primers may offer rapid and accurate detection of invasive species in ballast water.

• Korean Journal of Ecology and Environment
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• v.48 no.4
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• pp.219-228
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• 2015

To secure water resources, dams are normally constructed on the upper - middle part of streams, and it generates physical disturbances such as habitat alteration and stream fragmentation. Such construction can restrict movement of aquatic organisms, especially for freshwater fish which is one of top predator in aquatic ecosystem, and cause genetic fragmentation and community change. In this study, to investigate impact of habitat alteration after dam construction on freshwater fish, we monitored fish community changes, and compared fish fauna between dam reservoir and inflows. Additionally, movement characteristics and habitat boundaries of four species were identified by radio telemetry method. The study was conducted in the Gunwi Dam which was constructed in December 2010. Radio telemetry was applied to Pungtungia herzi, Zacco platypus (living lotic and lentic), Silurus asotus (lentic preferred species) and Zacco koreanus (lotic preferred species). The number of species was remarkably decreased (4 family, 10 species) comparing with before the dam construction (7 family, 15 species). Specifically, Coreoleuciscus splendidus, Niwaella multifasciata, Liobagrus mediadiposalis, Coreoperca herzi and Odontobutis platycephala that inhabit in the lotic environment were not collected in the study area. A total of 8 species were caught in both the dam reservoir and tributaries except 2 species (C. auratus and S. asotus). Sorenson's similarity between the reservoir and its tributaries was high (0.842). All of the radio tagged species stayed in the reservoir except S. asotus which moved to the tributary. These species mainly utilized the shallow littoral zone as a habitat. These results could be useful as a baseline data for efficient management of fishes in lakes.

• Korean Journal of Ecology and Environment
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• v.45 no.2
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• pp.232-241
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• 2012

The seasonal changes in phytoplankton species composition, standing crops, dominant species, species diversity and physico-chemical characteristics in the Unmun dam were studied, from August, 2009 to April, 2010. The phytoplanktons of a total of 121 taxa were identified, the composition of phytoplankton community was characterized by a green algae and diatoms, and the quantity composition of standing crops was dominated by diatoms and dinophyceae. The diatoms Aulacoseria granulata and blue-green alga Anabaena planktonica in Summer, Peridinium voltzii in Autumn and Asterionella formosa in Winter to Spring were, especially, prominent. The seasonal changes of the biomass varied from 578 cells $mL^{-1}$ to 12,938 cells $mL^{-1}$, and the maximum algal density was observed in April, Asterionells formosa contributed to 88% of the total cell numbers. The species diversity and richness were highest during autumn, and dominance index was highest in the spring season.

• The Korean Journal of Soil Zoology
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• v.6 no.1_2
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• pp.25-31
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• 2001

Oribatid mite communities in the process of litter decomposition were analyzed In Korean pine (Pinus koraiensis) forests of Namsan and Kwangreung, which were supposed to be under different environmental selective pressures. Oribatid mites were collected bimonthly from the litter bags (mesh size 0.4 mm, 1.7 mm) which was set up in the forest floor of study sites. This study had been carried out from Jan., 1997 to Sept., 1998. Species abundance of Kwangreung (mesh size 1.7 mm) was significantly higher than that of Namsan (mesh size 1.7 mm), but total no. of species did not exceed 30 species in all study sites. Concerning body length, medium sized oribatid mites (0.3-0.7mm) were more abundant than small ( < 0.3 mm) and large ( > 0.7 mm) sized mites. In Kwangreung, species whose body lengths were 0.2 mm to 0.5 mm were major group. However, a little larger species than Kwangreung's major group were dominant in Namsan. Sorenson similarity index and cluster analysis suggested that there were qualitative and quantitative differences in species composition in Namsan and Kwangreung. More species were collected in May through September than the other sampling times, but the pattern was rather different between first year and second year. Newly immigrant species were high in May in the first year and many of them regained on next year. Diversity indices suggested that species diversity of Kwangreung was higher than that of Namsan. Nearly 70% of total individual abundance was occupied by several dominant species in Namsan and Kwangreung . In the litter bags of mesh size 1.7 mm, the most dominant species was Trichogalumna nipponica in Namsan and Kwangreung, but in the litter bags of mesh size 0.4 mm in Kwangreung it was Ramusella sengbuschi which is smaller than T. nipponica. And important species related to litter decomposition were selected as follows; T. nipponica, Epidamaeus coreanus, Scheloribates latipes, Ceratozetes japonicus, Ramusella sengbuschi, Eohypochthonius crassisetiger, and Cultroribula lata.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.88.2-88.2
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• 2011

본 연구는 아연/공기전지 설계기술 개발을 위한 기초 연구로서 전산해석을 이용하여 전해질 유동에 따른 아연/공기전지의 성능 예측에 관한 것이다. 전산해석모델은 전기화학 방정식과 유체유동 방정식으로 구성하였으며, 화학종 반응에 관한 지배방정식으로는 Nernst-Planck식을 이용하였고 전극표면의 전기화학반응은 Butler-Volmer식을 이용하였다. 또한 유체유동 방정식은 Navier-Stoke식을 적용하여 전해질 유동에 따른 전기화학적 성능 변화를 모사하였다. 아연/공기전지 성능 평가 실험으로부터 얻은 I-V 곡선과 전산해석결과와의 비교/분석을 통하여 전기화학모델의 타당성을 검증하였으며, 유체 유동 방정식과의 연동해석을 적용하여 전해질 유입 위치 및 유입 속도에 따른 아연/공기전지의 성능 변화를 조사하였다. 아연/공기전지의 성능은 전해질 유입 위치가 아연극에 가까울수록, 유입 속도가 빠를수록 향상되는 것을 확인할 수 있었다.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2011.04a
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• pp.98-103
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• 2011

도심하천에서 채집된 어류는 총 7과 17종 315개체가 확인되었으며, 자연하천에서 채집된 어류는 6과 21종 1,033 개체가 조사되었다. 도심하천에서 출현한 한국 고유종은 치리(Hemiculter eigenmanni)와 얼룩동사리(Odontobutis interrupta) 2종(11.8%)이었으며, 생태계교란야생동물에 속하는 종인 배스(Micropterus salmoides)가 폐쇄형 하도습지에서 출현하였다. 자연하천에서 출현한 한국고유종은 쉬리 (C. splendidus), 배가사리(Microphysogobio longidorsalis) 등 총 13종(61.9%)으로 고유종의 빈도가 높았고, 멸종위기 II급에 속하는 종인 묵납자루(A. signifer)와 가는돌고기(Pseudopungtungia tenuicorpa) 등 2종(9.5%)이 조사되었다. 두 하천의 군집분석을 비교한 결과 도심하천이 자연하천에 비해 우점도와 균등도 지수가 높게 나왔다. 이와 같은 결과는 도심하천과 자연하천이 같은 유형의 서식처이지만 도심하천의 경우 양안 수변대와 제방구축, 하천정비, 고수부지의 시멘트화 등의 원인과 오염원의 유입, 풍부한유기물 때문인 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.226-226
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• 2023

하천유량, 댐유입량 등을 예측하기 위해 다양한 Long Short-Term Memory (LSTM) 방법들이 활발하게 적용 및 개발되고 있다. 최근 연구들은 s2s (sequence-to-sequence), Attention 기법 등을 통해 LSTM의 성능을 개선할 수 있음을 제시하고 있다. 이에 따라 본 연구에서는 LSTM-s2s와 LSTM-s2s에 attention까지 첨가한 모델을 구축하고, 시간 단위 자료를 사용하여 유입량 예측을 수행하여, 이의 실제 댐 운영에 모델들의 활용 가능성을 확인하고자 하였다. 소양강댐 유역을 대상으로 2013년부터 2020년까지의 유입량 시자료와 종관기상관측기온 및 강수량 데이터를 학습, 검증, 평가로 나누어 훈련한 후, 모델의 성능 평가를 진행하였다. 최적 시퀀스 길이를 결정하기 위해 R², RRMSE, CC, NSE, 그리고 PBIAS을 사용하였다. 분석 결과, LSTM-s2s 모델보다 attention까지 첨가한 모델이 전반적으로 성능이 우수했으며, attention 첨가 모델이 첨두값 예측에서도 높은 정확도를 보였다. 두 모델 모두 첨두값 발생 동안 유량 패턴을 잘 반영하였지만 세밀한 시간 단위 변화량 패턴 모의에는 한계가 있었다. 시간 단위 예측의 한계에도 불구하고, LSTM-s2s에 attention까지 추가한 모델은 향후 댐유입량 예측에 활용될 수 있을 것으로 판단한다.