• Title/Summary/Keyword: Research Environment

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A Study on Efficiency of Water Supply through Conjunctive Operation of Reservoirs and Multi-function Weirs in the Nakdong River (낙동강수계 댐과 다기능보의 연계운영을 통한 용수공급효율화에 관한 연구)

  • Ahn, Jung Min;Im, Toe Hyo;Lee, In Jung;Lee, Kyung-Lak;Jung, Kang Young;Lee, Jae Woon;Cheon, Se Uk;Park, In Hyeok
    • Journal of Korean Society on Water Environment
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    • v.30 no.2
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    • pp.138-147
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    • 2014
  • In order to determine the best operating rules for the Nakdong River, three cases were applied to analyze the simulated results of water supply capacity by HEC-ResSim model. This study discussed to present the best operating rules for conjunctive operating of existing the dams and new constructed the weirs through system network. The system network was constructed considering the water supply, the river environment and the operating facility. The water supply capacities are separately evaluated for each case applying the best rules. It is case1 that the dams are operated individually, case2 that the dams are operated in conjunction with the others dams, and case3 that dams and weirs are operated in conjunction with the others dams-weirs. Comparing the cases, case 3 has shown the best water supply capacity of the Nakdong River.

Comparison of Biochemical Profiles with Biogroups for the Identification of Cronobacter spp. (Enterobacter sakazakii)

  • Kim, Jung-Beom;Park, Yong-Bae;Kim, Woon-Ho;Kim, Ki-Cheol;Jeong, Hong-Rae;Kim, Dae-Hwan;Kang, Suk-Ho;Yong, Kum-Chan;Yoon, Mi-Hye;Park, Yong-Chul
    • Journal of Food Hygiene and Safety
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    • v.24 no.4
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    • pp.307-311
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    • 2009
  • The objectives of this study were to compare the biochemical profiles with biogroups for the identification of Cronobacter spp. (formally known as Enterobacter sakazakii) isolates using biochemical identification kits. A total of 38 Cronobacter spp. contained 5 clinical, 31 food, and 2 environmental isolates were used. All isolates were identified as Cronobacter spp. with the Vitek II system and ID 32E kit. The API 20E kit identified all isolates as Cronobacter spp. but the percentage identification was 51.1% for 16 of 38 isolates. These strains were contained to Biogroup 2, 9, 10, and 11. The utilization of inositol is a factor determining the percentage identification of Cronobacter spp. with the API 20E kit.

Short-Term Water Quality Prediction of the Paldang Reservoir Using Recurrent Neural Network Models (순환신경망 모델을 활용한 팔당호의 단기 수질 예측)

  • Jiwoo Han;Yong-Chul Cho;Soyoung Lee;Sanghun Kim;Taegu Kang
    • Journal of Korean Society on Water Environment
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    • v.39 no.1
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    • pp.46-60
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    • 2023
  • Climate change causes fluctuations in water quality in the aquatic environment, which can cause changes in water circulation patterns and severe adverse effects on aquatic ecosystems in the future. Therefore, research is needed to predict and respond to water quality changes caused by climate change in advance. In this study, we tried to predict the dissolved oxygen (DO), chlorophyll-a, and turbidity of the Paldang reservoir for about two weeks using long short-term memory (LSTM) and gated recurrent units (GRU), which are deep learning algorithms based on recurrent neural networks. The model was built based on real-time water quality data and meteorological data. The observation period was set from July to September in the summer of 2021 (Period 1) and from March to May in the spring of 2022 (Period 2). We tried to select an algorithm with optimal predictive power for each water quality parameter. In addition, to improve the predictive power of the model, an important variable extraction technique using random forest was used to select only the important variables as input variables. In both Periods 1 and 2, the predictive power after extracting important variables was further improved. Except for DO in Period 2, GRU was selected as the best model in all water quality parameters. This methodology can be useful for preventive water quality management by identifying the variability of water quality in advance and predicting water quality in a short period.

Freshwater Habitats of Pectinatella magnifica (Leidy 1851) Living in South Korea (낙동강 본류에 출현하는 담수 태형동물 Pectinatella magnifica (Leidy 1851)의 서식환경 연구)

  • Jeong, Hyungi;Lee, Kyung-Lak;Choi, Byoung-ki;Kwon, Heongak;Park, Hae-Kyung;Jeong, Gang-yong;Yu, Jae Jeong
    • Korean Journal of Environmental Biology
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    • v.33 no.3
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    • pp.352-359
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    • 2015
  • In order to investigate the occurrence of Pectinatella magnifica in Nakdong River, extensive series of sampling was conducted through July to November of 2014. Results revealed that these species show preference to attach themselves on natural substrates over artificial substrates. P. magnifica does not show preference for specified substrates, but itappearthat availability of substrates determines their specific distribution. Considering that most commonly found substrates in Nakdong River were natural substrates such as dead twig, woody plants or aquatic plants, it is possible that high availability of substrates is one of the principal factors which increase the rates of growth and distribution of P. magnifica.