• 한국물환경학회지
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• 제31권3호
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• pp.262-271
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• 2015

Laboratory study was undertaken to pursue the filter performance of a micro-filter module employing highly porous fiber media under a high filtration rate (over 1,500 m/day), faster than that of any conventional filter process. The effects of filtration rate, head loss, raw water turbidity, and filter aid chemicals on filter performance were analyzed. In spite of the extremely high filtration rate, the filter achieved an attractive efficiency, reducing the raw water turbidity by over 80%. As with other filter systems, the filter aid used (PAC in this study) greatly affected the performance of this particular fiber filter. Long term repetitive runs were additionally carried out to confirm the reproducibility of the filter performance. Finally, a comparison was carried out with other high rate filter systems which are either being tested for use in experimental studies, or are already commercially available.

• 한국작물학회지
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• 제33권4호
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• pp.350-352
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• 1988

This study was carried out to know the influence of turbidity of submerged water on photosynthetic rate of rice plant after water submerging treatment. Rice plants were transplanted in the pot at maximum tillering stage and they were sumberged for 3days at meiotic stage, 20days after transplanting, in the plastic container which had the clear and turbid water temperature adjusted around 24 to $25^{\circ}C$. Photosynthetic rate at 6 hours recovery after submergence was 41.5 to 54.2% compared to the control, but in the case of cultivar 'Nagdongbyeo', it was rapidly increased by 97.3 to 104.6% in the clear water and by 68.6 to 77.5% in the turbid water at 2 to 4 days recovery after submergence. Photosynthetic rates per plants at 6 hours to 4 days recovery after submergence were 128.3 to 245.5 $C_2$ mg.hr.$^{-1}$, in 'Samgamgbyeo' and 71.1 to 162.4 $CO_2$, mgㆍhr.$^{-1}$ in 'Nagdongbyeo' Photosynthetic rate to respiration ratio of rice plant recovery after submergence was lower compared to control plant and it was lower in 'Nagdongbyeo' than that in 'Samgangbyeo'.ngbyeo' than that in 'Samgangbyeo'.gangbyeo'.pos;.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2004년도 GIS/RS 공동 춘계학술대회 논문집
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• pp.241-246
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• 2004

The ocean signal that reaches the detector of an imaging system after multiple interactions with the atmospheric molecules and aerosols was retrieved from the total signal recorded at the top of the atmosphere (TOA). A simple method referred to as 'Path Extraction' applied to the Landsat-TM ocean imagery of turbid coastal water was compared with the conventional dark-pixel subtraction technique. The shape of the path-extracted water-leaving radiance spectrum resembled the radiance spectrum measured in-situ. The path-extraction was also extended to the SeaWiFS ocean color imagery and compared with the standard SeaWiFS atmospheric correction algorithm, which relays on the assumption of zero water leaving radiance at the two NIR wavebands (765 and 865nm). The path-extracted water-leaving radiance was good agreement with the measured radiance spectrum. In contrast, the standard SeaWiFS atmospheric correction algorithm led to essential underestimation of the water-leaving radiance in the blue-green part of the spectrum. The reason is that the assumption of zero water-leaving radiance at 755 and 865nm fails due to backscattering by suspended mineral particles. Therefore, the near infrared channels 765 and 865nm used fur deriving the aerosol information are no longer valid for turbid coastal waters. The path-extraction is identified as a simple and efficient method of extracting the path radiance largely introduced due to light interaction through the complex atmosphere carried several aerosol and gaseous components and at the air-sea interface.interface.

• 대한원격탐사학회지
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• 제20권3호
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• pp.153-162
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• 2004

In the summer of 1998-2001, a huge flood occurred in the Yangtze River in the eastern China. Low salinity water less than 28 psu from the river was detected around the southwestern part of the Jeju Island, which is located in the southern part of the Korean Peninsula. We studied how to detect low salinity water from the Yangtze River, that cause a terrible damage to the Korean fisheries. We established a relationships between low salinity at surface, turbid water from the Yangtze River and digital ocean color remotely sensed data of SeaWiFS sensor in the northern East China Sea, in the summer of 1998, 1999, 2000 and 2001. The salinity charts of the northern East China Sea were created by regeneration of the satellite ocean color data using the empirical formula from the relationships between in situ low salinity, in situ measured turbid water with transparency and SeaWiFS ocean color data (normalized water leaving radiance of 490 nm/555 nm).

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.649-654
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• 2002

In summer season of 1998, a huge flood occurred around the Yangtze River in the eastern China. The low salinity water less than 28 psu from the river was detected around the southeastern part of the Jeju Island which is located in the southern part of the Korean peninsula. We studied how to detect low salinity water from the Yangtze River, which gives terrible damages to the Korean fisheries. We got the relationships between low surface salinity, turbid water from the Yangtze River and digital ocean color using remote sensing of SeaWiFS satellite in the northern East China Sea in summer seanson of 1998, 1999, 2000 and 2001. The charts of salinity in the northern East China Sea were made by the regenerating of the satellite ocean color data with the formula from the relationships between low salinity, in situ turbid water (transparency) and satellite ocean color.

• 대한원격탐사학회지
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• 제15권4호
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• pp.321-327
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• 1999

As an example of many possible applications of OSMI data, we present a method to detect red tides. In Korean waters, red tides usually occur in the South Sea where the turbidity is usually high due to strong tidal mixing in the shallow sea. The conventional case 1 chlorophyll algorithm cannot be applied since it cannot distinguish chlorophyll from SS (suspended sediments). In October 1998, a red tide outbreak occurred off the coast of KunSan. We analyzed the SeaWiFS data of the outbreak. The standard SeaWiFS chlorophyll algorithm OC-2 was poor in identifying the red tides. However, comparison of spectra of normalized water-leaving radiance indicates that red tide pixels can be distinguished from sediment-laden pixels. Channel 443 and 555 were effective in showing the spectral characteristics. We suggest K490 algorithm as an example in summarizing the information of the spectra and thereby in distinguishing the red tide pixels. Further development is desirable.

• 생태와환경
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• 제40권1호
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• pp.130-142
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• 2007

본 연구에서는 용담댐의 탁수 방류로 인한 하류 하천의 영향을 알아보기 위하여 생태계 건강성 평가 모델, 물리적 서식지 평가 모델, 해부학적 건강성 평가 모델을 적용하였다. 건강성 평가 결과 $S1{\sim}S4$의 생태계 건강도는 평균 43으로 최적${\sim}$ 양호 상태였고, 물리적 서식지 건강도는 평균 154로 양호상태로 나타나 건강도가 양호하게 유지되고 있는 것으로 나타났다. 한편 개체의 건강도를 평가하는 해부학적 건강도 평가 결과 10개 메트릭에서 이상증상이 나타나지 않아 어류 건강성에 대한 영향은 없는 것으로 판단되었다. 한편, 부유물의 증가에 따른 어류 아가미의 전자현미경적 영향 분석을 위해 탁도 처리군 및 대조군의 비교분석 결과에 따르면, 어류 아가미에서 많은 부유물 미세 입자가 관찰되어 고탁도에 장기간 노출될 경우 건강성에 영향을 미칠 가능성이 있을 것으로 사료되었다. 또한, 탁도 증가에 따른 부유사 이동에 의한 어류의 물리적 서식지 영향 분석(특히, 하상 매몰도 및 하상특성 분석)을 위해 서식지 건강성 평가모델을 적용 평가한 결과에 따르면, 대상 조사지역$(S1{\sim}S4)$이 대조군 지역(C1, C2)보다 더 좋은 것으로 나타났다. 즉, 부유사의 증가는 현재의 결과로는 서식지 건강도에 영향을 주지 않는 것으로 나타나 어류의 먹이사슬, 산란장 및 서식처에 대한 부정적 영향은 없는 것으로 사료되었다. 한편, 이런 결과는 단기간 연구 결과에 의한 현재 상태의 건강도 평가의 결과이지만 향후 탁수가 지속될 경우 수 환경이 어떻게 변할 것인가에 대해서는 사후 지속적인 모니터링이 이루어져야 하며, 향후 $3{\sim}5$년 후의 지속적인 모니터링을 실시할 경우 용담댐 건설에 의한 생태 건강도가 어떻게 변할 것인지에 대한 정보를 제공하기 때문에 지속적인 모니터링이 요구된다.

• 보존과학회지
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• 제38권1호
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• pp.14-32
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• 2022

Underwater photographing and image recording are essential for pre-excavation survey and during excavation in underwater archaeology. Unlike photographing on land, all underwater images suffer various quality degradations such as shape distortions, color shift, blur, low contrast, high noise levels and so on. Outcome is very often heavily photographing equipment and photographer dependent. Excavation schedule, weather conditions, and water conditions can put burdens on divers. Usable images are very limited compared to the efforts. In underwater archaeological study in very turbid water such as in the Yellow Sea (between mainland China and the Korean peninsula), underwater photographing is very challenging. In this study, off-site image distortion and color compensation techniques using an image processing/analysis software is investigated as an alternative image quality enhancement method. As sample images, photographs taken during the excavation of 800-year-old Taean Mado Shipwrecks in the Yellow Sea in 2008-2010 were mainly used. Significant enhancement in distortion and color compensation of archived images were obtained by simple post image processing using image processing/analysis software (PicMan) customized for given view ports, lenses and cameras with and without optical axis offsets. Post image processing is found to be very effective in distortion and color compensation of both recent and archived images from various photographing equipment models and configurations. Merits and demerit of in-situ, distortion and color compensated photographing with sophisticated equipment and conventional photographing equipment, which requires post image processing, are compared.

• 대한토목학회논문집
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• 제26권2D호
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• pp.341-347
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• 2006

임하호는 안동호 유역과 지형학적으로 인접되어 있지만 강우강도에 따른 탁수발생에는 큰 차이를 보이고 있으며 이러한 원인을 밝히는 것은 매우 중요하다. 본 연구에서는 안동호와 임하호 유역을 연구대상지로 선정하여 준경험 토사유실모델인 RUSLE 모델을 이용하여 고탁수 발생에 큰 영향을 미치는 토사유실량을 비교 평가하였다. 먼저, 환경부에서 구축한 토지피복도를 기반으로 토사유실에 가장 민감한 농경지비율을 분석한 결과, 안동호유역은 11.88%, 임하호유역은 14.95%로서 임하호유역이 3.07% 높게 평가되었다. 또한 RUSLE 인자의 분석에서는 경작인자를 제외한 모든 인자들이 임하호유역에서 높게 평가되었으며, 이는 시간적인 변화를 보이는 강우자료를 제외한 토양, 지형 그리고 토지피복상태가 임하호유역이 안동호유역에 비해 토사유실에 취약한 구조를 가지고 있음을 의미한다. 토사유실량 평가에서도 안동호와 임하호유역이 각각 1,275,806 ton과 1,501,608 ton으로서, 임하호유역이 안동호유역에 비해 225,802 ton만큼 높게 평가되었다.

• 한국지반환경공학회 논문집
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• 제11권4호
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• pp.13-18
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• 2010

본 논문은 반변천 상류지류(임하댐 유입지천 유역)의 토양들에 의해 탁수 발생 시 부유된 물질의 특성을 규명하고자 하였다. 토양시료는 탁수유발 지역인 영양 일대 5개 지점과 청정지역인 청송 일대 2개 지점에서 시료를 채취하여 실험을 수행하였다. 청정지역 토양에 비하여 탁수지역 토양을 증류수에 분산 시 pH가 높게 나타나는 경향을 보이고 있었다. 탁수지역 토양의 XRD 분석결과 침전 전에는 모든 시료에서 석영, 일라이트, 장석 등이 확인되었다. 3일간 침전 후 탁수지역의 부유물은 대부분 석영(Quartz)과 일라이트(Illite)가 주로 존재하였다. 청정지역의 신흥교 토양에는 일라이트(Illite)만 조사되었다. 원소 분석결과 모든 지점에서 침전 전 다량의 $SiO_2$로 구성되었던 광물질들이 3일간 침전 후, $SiO_2$의 함량은 줄어든 반면 일라이트의 주요 구성성분인 $K_2O$, MgO, CaO, $Al_2O_3$ 및 $Fe2O_3$의 함량은 상대적으로 증가하는 양상을 보였다. 따라서 탁수를 유발시키는 주요 광물질은 일라이트(Illite)임을 확인하였다.