• 해양환경안전학회지
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• 제2권1호
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• pp.89-95
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• 1996

This paper describes a fuzzy controlled pre-chlorination technique for purifying the pulluted raw water in water purification lants. For the purpose of obtaining the high quality water, the appropriate pre-chlorine dosage rate has to be continuously adjusted according to a change in quality of a intake raw water, weather, solar nergy mount, temperature and etc. Therefore, the method of expressing an expert's empirical knowledge cumulated from his past carrier by fuzzy reasoning and the fuzzy controller design technique is necessary.In this paper fuzzy membership functions and rules accordingto emprircal knowledge and experimental field data were obtained, And also fuzzy cintriller design using four feedforward components for the determination of pre-chlorine dosage rate and four feedback ones for the compensation of its dosage rate with residual chlorine and its change rate, was executed.

• 한국수산과학회지
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• 제31권5호
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• pp.685-694
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• 1998

To evaluate the water quality characteristic after construction of Keum river estuary barrage, water quality analysis were conducted on August October in 1995 and January, May in 1996 respectively. The results were summarized as follows. The concentrations of COD were in the range of 1.01~5.10 (mean 2.50)mg/$\ell$ for surface water and 0.51$\~$6.68 (1.88)mg/$\ell$ for bottom water. The concentrations of dissolved inorganic nitrogen (DIN) were in the range of 1.26$\~$105.91 (29.66)$\mu$g-at/$\ell$ for surface water and 1.42$\~$68.38 (19.12)$\mu$g-at/$\ell$ for bottom water. The concentrations of phosphate phosphorus were in the range of ND$\~$0.99 (0.34)$\mu$g-at/$\ell$ for surface water and 0.17$\~$1.04 (0.49)$\mu$g-at/$\ell$ for bottom water. The nitrogen ratio to the phosphorus were as high as 3.5$\~$849.5 (146.5). Therefore, Phosphate phosphorus was playing an important role in phytoplankton growth as limiting factor in Keum river estuary. The correlation coefficient of salinity and DIN according to COD was shown to -0.757 and -0.874 respectivity. Mean values of eutrophicaton indies were calculated to 9.7, 7.2 for surface and bottom water, these values were exceeding 1, the value of eutrophication criteria. Especially station 1$\~$3 were shown over 10 as eutrophication indices. Therefore, Keum river estuary could be evaluate to possibility area for breakout of red tides.

• 수산해양교육연구
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• 제25권4호
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• pp.819-827
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• 2013

Water quality has been considered to be one of sanitation standard operating procedures (SSOP) for hazard analysis critical control points (HACCP) application in aquaculture farms. This study was conducted to evaluate a hazard caused by water used in aquaculture farm of rainbow trout. The water quality was analyzed to investigate both physiochemical and bacteriological level in water samples collected from aquaculture farm of rainbow trout, Oncorhynchus mykiss. No significant difference were observed on water temperature and pH from season to season. However, the levels of dissolved oxygen were decreased as the outside temperature was increased, even if the levels were adequate for aquaculture. Also, other physiochemical analysis including biochemical oxygen demand (BOD), chemical oxygen demand (COD) and suspended solid (SS) revealed that the waters for aquaculture analyzed in this study was suitable for rainbow trout aquaculture. The bacterial analyses were also revealed that the waters for aquaculture were met to both coliform group (<18 MPN/100mL) and viable cell count (<100 CFU/mL). However, some of waste waters from aquaculture farms showed higher levels of BOD and COD than those of waste water standard (<2 ppm), suggesting that regular cleaning of fish tank and precipitation tank is needed.

• 한국해양환경ㆍ에너지학회지
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• 제14권1호
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• pp.1-10
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• 2011

전남 서해 갯벌 연안경계부 수질특성을 파악하기 위하여 5개 해역(무안만, 탄도만, 함평만, 신안지도 및 영광해역)을 대상으로 2008년에서 2009년까지 2년 동안 한 달에 두 번씩 현장조사를 실시하였다. 수온은 $1.3{\sim}31.1^{\circ}C$로 연교차가 컸다. 염분은 비교적 32 내외로 균일하였으나 강우가 집중되는 시기에 염분 함량이 20 이하로 저염화가 나타났으며, 수온 변화에 따라 용존산소는 하계에 낮고 동계에 높았다. 수소이온농도는 용존산소와 비슷한 분포경향을 보였다. 부유물질의 경우 영광해역에서 100 mg/l 이상으로 높은 함량을 보였다. 화학적 산소요구량은 1 mg/l 내외로 큰 변화가 없었으며, 용존무기질소와 용존무기인은 담수유입이 증가하는 시기에 높은 함량을 보였다. 용존무기질소는 겨울과 초봄에 낮은 반면에 용존 무기인은 월별 변화 없이 균일한 분포를 보이다가 2009년 7월 이후 다소 증가하는 경향을 보였다. 엽록소a는 봄철에 $10\;{\mu}g/l$내외로 나타났으며 이후 대부분 비슷한 분포 경향을 보이나 특히 타 해역에 비하여 여름철에 영광해역에서 높게 나타났다. 해역별 수질특성을 비교하기 위하여 실시한 주성분분석 결과는 다음과 같이 뚜렷한 특징을 보였다. 무안만과 탄도만에서 제 1 주성분 요인은 담수유입 변동이었으며, 신안지도 해역과 영광해역에서는 수온의 변화로 나타났다. 함평만에서는 담수유입 변동과 수온변화의 영향이 제 1 주성분 요인으로 복합되어 나타났다.

• 해양환경안전학회지
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• 제23권5호
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• pp.524-531
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• 2017

본 연구는 생태계 모델을 이용하여 부산연안으로 유입되는 부하량 삭감에 따른 해역의 수질개선 정도를 예측하였다. 모델링 결과에 의하면 COD, T-N, T-P 모두 수영만 연안과 낙동강 하구에서 뚜렷한 개선을 나타냈으며, 수영만을 제외한 만 중부에서 만 동쪽까지는 수질개선이 거의 나타나지 않았다. 이는, 부산연안이 남해에 위치한 다른 해역에 비해 개방형경계를 가지고 있어서, 물질교환이 빠르기 때문으로 판단된다. 수질개선을 위한 본 해역의 삭감 COD 부하량은 타 해역에 비해 적었고, 총 유입부하량에 대한 삭감비율 또한 작게 나타났다. 본 연구에 적용한 부하삭감량을 적용하면 수영만, 낙동강 하구부근에서 뚜렷한 수질개선효과를 얻을 수 있을 것으로 판단된다.

• 해양환경안전학회지
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• 제5권2호
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• pp.57-65
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• 1999

The in situ observations and the seawater analyses were conducted at all seasons from July 1996 to April 1999 for the purpose of describing the characteristics of seasonal variations of water quality in Mokpo harbour, Korea. Vertical stratification started to be formed in water column in spring, developed in summer and disappeared in fall. In summer, vertical density distribution of water column was found to be in stable structure with lower temperature and higher salinity of bottom water, and the vertical mixing of water between surface and bottom layers was restricted. In winter, however, surface water was found to be similar to bottom water in temperature and salinity, and water column was in unstable structure and in well-mixed condition between surface and bottom waters. The saturation percentage of dissolved oxygen(DO) in bottom water of inner part of Mokpo harbour at all seasons was shown to be decreased to the third grade or under the third grade of Korean standards of seawater quality. In particular, dissolved oxygen was oversaturated in surface water and undersaturated in bottom water in summer, due to stratification and organic pollution. The difference of DO concentration between surface and bottom waters was found to be greater in spring and summer than in fall and winter, due to stratification and photosynthesis of phytoplankton. The concentrations of chemical oxygen demand(COD) over the entire waters of Mokpo harbour were found to fluctuate from below the third grade to the first grade of Korean standards through all seasons and COD concentrations of same seasons were shown to be different year after year. In particular, in view of COD, the annual average seawater quality of Mokpo harbour was evaluated to be in third grade of Korean standards, due to organic pollution. The average COD of surface water was greater than that of bottom water in spring and summer, due to the autochthonous COD caused by production of phytoplankton in surface waters, while the average COD of surface water was similar to that of bottom water in fall and winter, due to the vertical mixing of water between surface and bottom layers.

• 한국해양환경ㆍ에너지학회지
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• 제7권4호
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• pp.159-163
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• 2004

본 연구는 한국의 서남해 연안의 새우 양식장을 대상으로 pH, 염분, 용존산소, 암모니아질소 및 황화수소와 같은 새우 양식장의 수질과 저질을 조사한 후, 새우 양식장의 수질과 저질을 개선할 수 있는 방안을 모색하고자 하였다. 즉, 맑은 날씨와 흐린 날씨로 구분하여 현장의 새우 양식장에서의 용존산소의 일 변화를 측정한 결과, 정도의 차이는 있었으나 정오부터 오후 6시까지 증가하다가 점점 감소한 후 새벽 6시 경에 최소값을 보인 후 다시 점점 증가하는 경향을 보였다. 이와 같은 결과는 새우 양식장의 관리가 취약한 새벽녘에 용존산소의 부족으로 인해 새우가 질식사 학 수 있으며, 계속적인 저 산소는 저질을 악화시켜 암모니아질소나 황화수소의 농도를 증가시킬 수 있음을 시사하므로 지나치게 용존산소가 낮은 경우와 용존산소가 지나치게 높은 경우에는 인위적 또는 자동적으로 용존산소를 조전할 필요가 있는 것으로 판단되었다. 또한, 현장의 새우 양식장에서의 암모니아 질소는 새우 양식장의 수질 기준을 초과하는 0.172-2.298 ppm으로 높게 나타나고 있었고, 황화수소 농도도 새우 양식장의 농도 기준을 훨씬 상회하는 0.075 ppm까지 나타나고 있어 암모니아질소의 생성 억제와 황화수소의 발생 억제가 새우 양식장의 수질관리에 있어 중요한 요인임을 알 수 있었다.

• Ocean and Polar Research
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• 제28권4호
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• pp.467-473
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• 2006

The EM 120, a newly installed multibeam echo sounder on RM Onnuri, has several advantages over the previously installed SeaBeam 2000 in performance and thus data quality. The EM 120 system provides a bottom topographic map with high resolution by (1) increasing the number of beams, (2) increasing the across track swath range, (3) measuring the more accurate sound velocity within the water column, and (4) improving stabilization for pitching, rolling, and yawing of the ship. This study compares EM 120 and SeaBeam 2000 echo sounders in terms of the data quality from the same survey area in the Clarion-Clipperton Zone, NE Pacific. Our result shows that the EM 120 provides more precise topographic data than the SeaBeam 2000. Although overall trends of data, such as topographic direction and relief, are similar for both echo sounders, the water depths measured by the EM 120 are shallower than that of SeaBeam 2000 by 80 to 90 meters.

• 생명과학회지
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• 제19권7호
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• pp.943-948
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• 2009

Physical and chemical analyses of water discharged from 4 crowded farms (Sungsan, Pyosun, Wimi and Daejung) in Jeju island were performed from July, 2006 to Dec, 2006, and the result of the analyses showed that hydrogen ion concentrations (pH) for water discharged from Sungsan farm was 7.74, Pyosun was 7.68, Wimi was 7.68 and Daejung was 7.7. Salinity levels for Sungsan, Pyosun and Wimi had an average of 31$\sim$33 $^\circ$/$_\circ$$_\circ$ indicating characteristics of far distance areas, whereas that of Daejung was 28.81 %, which was far lower compared to regular sea water salinity. As the result of measuring dissolved oxygen (DO) for each area, each area showed first graded DO for each discharged water based on water quality level for each sea district. The result of measuring the temperature for discharged water showed that water temperatures for summer were 23$\sim$25$^\circ$C, and those for winter were 16$\sim$ 18$^\circ$C. Nitrogen concentrations for discharged water exceeded each sea area's water quality level in all farms. In the case of phosphate, its average value was 0.48 mg/l for Sungsan, 0.55 mg/I for Pyosun, 0.66 mg/I for Wimi, and 0.44 mg/l for Daejung, and chemical oxygen demand (COD) was shown to be 1.5 mg/l 1.8 mg/I, 1.6 mg/I and 2.3 mg/I for Sungsan, Pyosun, Wimi and Daejung respectively. For suspended solids (SS), the average concentration was 19.3 mg/I, 21.2 mg/I, 21.3 mg/I and 18.5 mg/I for Sungsan, Pyosun, Wimi and Daejung respectively. The results of physical and chemical analyses for discharged water in farms based on time showed that almost all items were shown to increase in the forenoon and decrease, overall, in the afternoon.

• 해양환경안전학회지
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• 제20권3호
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• pp.270-276
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• 2014

Seasonal characteristics of water and sediment qualities and potential effects of the freshwater discharge from a small tide embankment interior in a coastal area in Goheung county were investigated from May to September in 2012. Chemical oxygen demand values (COD) were mostly higher than 2 mg/L in summer ebb tide, which exceed the standard value of water quality criteria II of acceptable level for aquaculture activities. Nitrogen and phosphorus were found as the limiting nutrients for algae growth in summer and fall and in spring, respectively. Nitrogen was the limiting nutrient for diatom growth in the whole studied period. The sudden high values of COD, ammonia, dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) were found in water sample collected from station 5 which located in front of the tide embankment sluice gate during spring ebb tide. The freshwater discharge form the tide embankment interior maybe affected the survey areas during a short time interval. Mean values of eutrophication index of the surveyed coastal region in spring, summer and fall were all bigger than 1. Water quality was mostly considered at level II which acceptable for aquaculture activities. Sediment quality in this study was generally in the range of standard for fisheries environment.