• 한국물환경학회지
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• 제33권4호
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• pp.394-402
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• 2017

In korea, TMDL is being implemented to manage nonpoint pollution sources as well as point pollution sources. LDC is being used for the planning of TMDL. In order to analyze the water quality using LDC, it is necessary to prepare FDC using the daily flow data. However, only the daily flow data is measured at the WAMIS branch, and 8days flow data and water quality data are measured at the monitoring Networks. So, in many researches, the water quality is being grasped by deriving the LDC using the 8days flow or the daily flow obtained by various methods. These fluctuations may lead to differences in determining whether the target load is achieved. In this study, each LDC was prepared using the 8day flow and the related daily flow. Then, the effect using different flow data on the achievement of target load was compared according to flow conditions. As a result, the difference ratio in the number of overloads under flow condition was showed 19% in high flows, 42% in moist conditions, 49% in mid-range flows, 41% in dry conditions, and 104% in low flows. In the top ten watershed with the highest difference ratio, the flow became lower the difference ration increases. These differences can cause uncertainty in assessing the achievement of target load using LDC. Therefore, in order to evaluate the water quality accurately and reliably using LDC, accurate daily flow data and water quality data should be secured through the installation of national nonpoint measurement network.

• ALGAE
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• 제20권2호
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• pp.127-132
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• 2005

Algal growth potentials were probed by algal growth rates, maximal PSII quantum yields and ATP amount as well as dry weights of algae to evaluate the water fertility due to the algal growth in the stream (CT) and stagnant watershed (WW). Oscillatoria agardhii (CY) and Coelastrum reticulatum (CH) were cultured in nitrogen (N) and phosphorus (P) starvation media (CH-10 medium) and re-inoculated in CT and WW for 7 days. Cell division rates of CY were the highest (k = 7.5) in WW after N starvation, while those of CH were the hight (k = 2.97) in WW after P starvation. The growth of CY was limited by P, while that of CH was by N. Conversely, maximal PSII quantum yields of CH were generally higher than those of CY in CT and WW according to culture time. CY was much more sensibly adapted than CH according to the variations of nutrient amounts in WW. The water fertility was much higher in WW than in CT. The potential assessment tool for water fertility will be able to compensate for the limit of physio-chemical analyses and to be applied as a monitoring system to forecast red-tide.

• 한국정보통신학회논문지
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• 제12권11호
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• pp.1980-1986
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• 2008

디지털 워터마크 기법은 음악, 영상, 동영상에 대한 저작권과 재산권의 보호 및 인증, 데이터 손실 여부 판단, 복사 방지 및 추적 등을 목적으로 한 사후 재산권의 보호 기술로 제안되었다. 본 연구에서는 워터마크의 기하학적인 왜곡에 대한 공격에 견고하게 하도록 영상의 전 처리 과정을 거친다. 그리고 선택된 기하학적인 불변 점을 골라 여러가지 영상처리에 강인하며 일정 기간 압축 저장되는 영상에서도 워터마킹이 유지되도록 워터 쉐드(watershed) 분할 기법을 이용한 의료 영상 보안 알고리즘을 제안한다. 본 논문에서 제안한 워터마킹 알고리즘은 의료 영상에 대한 RST공격, JPEG 압축 공격 그리고 필터링 공격보다 강인함을 확인하였다.

• 한국환경농학회지
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• 제27권2호
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• pp.111-119
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• 2008

전북도내에서 농업용수원으로 사용되고 있는 소규모 하천들의 수질 및 오염부하량 조사를 통해 효율적인 수질개선을 위한 기초자료를 얻고자 본 시험을 수행하였다. 24개 하천의 수질은 EC가 $0.07{\sim}0.52$ dS/m, BOD가 $0.1{\sim}5.0$ mg/L, $COD_{Cr}$이 $0.6{\sim}17.7$ mg/L 등 이었으며, 범위는 다양하였으나 연도에 따른 평균값은 큰 차이를 보이지 않았다. 또한 ${SO_4}^{2-}$은 $5.7{\sim}52.7$ mg/L, $Cl^-$함량은 $0.9{\sim}57.5$ mg/L, $Na^+$함량은 $2.5{\sim}48.9$ mg/L의 범위를 보여 관개용수 수질로는 양호한 상태였다. 조사하천 대부분의T-N 함량은 5.0 mg/L 이하, T-P함량은 0.10 mg/L이하였으나 일부 하천에서 5.0 mg/L 이상의 질소를 함유하고 있는 경우가 있어 관개수질을 고려한 합리적인 시비가 필요한 것으로 나타났다. 강우기의 EC, $Ca^{2+},\;Mg^{2+},\;K^+$ 및 $Na^+$ 등의 함량은 감소하였지만, BOD, $COD_{Cr},\;COD_{Mn}$, T-N 및 T-P의 농도는 뚜렷한 차이를 보이지 않았으며, 높은 농도의 SS가 하천 유량의 증가와 함께 유출되고 있어 강우기의 지표면 유출이 수계에 영향을 주는 것으로 나타났다. 조사하천의 오염부하량은 BOD가 $9.6{\sim}757.9$ kg/day, T-N이 $51.2{\sim}1418.5$ kg/day, T-P가 $0.3{\sim}44.7$ kg/day로 유역 및 성분에 따라 많은 차이를 보이고 있었다. 갈수기에 비하여 강우기에 BOD는 $3.0{\sim}4.4$배, T-N는 $3.0{\sim}4.0$배, T-P는 $4.1{\sim}5.6$배의 부하량 증가를 보여 강우기에 주변 유역에서의 유기물을 비롯한 각종 영양염류의 유출이 많아지고 있었다. 논 면적비율이 30%이상인 하천유역(A그룹)이 30%이하인 하천(B그룹)유역이 비하여 영농기였던 7월의 강우기에 유량과 영양물질의 유달부하량이 상대적으로 적게 나타났으며, 갈수기 대비 강우기의 부하량 증가도 B그룹에서 유량이 5.7배 증가한 것에 비교하여 A그룹의 유량 증가는 2.3배로 적게 나타났다. BOD, T-N, T-P의 부하량과 유량과의 회귀식 결정계수($R^2$)는 BOD가 $0.8025^{**}$, T-N이 $0.9229^{**}$, T-P가 $0.7612^{**}$으로 유량과 T-N 부하량과의 상관이 가장 높게 나타났다.

• 생태와환경
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• 제51권4호
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• pp.354-364
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• 2018

본 연구는 2008년부터 2016년까지 한강 지류 중랑천을 대상으로 수환경 변화에 따른 어류 군집 양상을 파악하고자 실시하였다. 조사결과, 중랑천에서 서식하는 어류는 총 9과 37종 8,421개체로 나타났으며 과별 출현 종수는 잉어과에서 23종(62.2%)으로 가장 많은 종이 출현하였고, 생태계교란종 및 외래종은 모두 강우기 후 출현하는 특성을 보였다. 수질변화에 따르면, BOD, EC, TN, TP의 변화는 강우량의 증가에 따라 감소하는 양상을 보이는 반면, SS 변화는 증가하는 양상을 보였다. 지점간 CA결과 한강 본류와 인접한 St. 7과 St. 1, 3, 5가 어류의 출현양상 차이를 보였으며, PCA 분석결과 상류에서 하류, 강우기 전과 후의 어류출현양상과 유기오염지표의 변화 양상을 보였다.

• 한국물환경학회지
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• 제26권4호
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• pp.648-653
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• 2010

Discharged pollution load for the management of Total Maximum Daily Loads (TMDLs) is calculated on the basis of rainfall data for reference year. Rainfall has an influence on discharged pollution load in unit watershed with combined sewer system. This study reviewed the status of discharged pollution load and rainfall conditions. We also investigated rainfall effects on discharged pollution load by analyzing change of the load in accordance with increase of rainfall. The change ratio of discharged pollution load was 18.6% while inflow load only 5.8% for 5 years from 2004 to 2008 in Daejeon district. The greatest rainfall and rain days were over 2 times than the least during the period. This change in rainfall could have great effect on discharged pollution load. The analysis showed that discharged pollution load increased 2.1 times in case rainfall increased 2 times and 1.2 times in case rain days increased 2 times. Rainfall effects, therefore, should be considered to make resonable evaluation of discharged pollution load in the assessment of annual performances.

• 한국물환경학회지
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• 제32권6호
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• pp.570-581
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• 2016

A watershed model was constructed using the Hydrological Simulation Program Fortran to predict the water quality, especially chlorophyll-a concentraion, at major tributaries of the Nakdong River basin, Korea. The BOD export loads for each land use in HSPF model were estimated at $1.47{\sim}8.64kg/km^2/day$; these values were similar to the domestic monitoring export loads. The T-N and T-P export loads were estimated at $0.618{\sim}3.942kg/km^2/day$ and $0.047{\sim}0.246kg/km^2/day$, slightly less than the domestic monitoring data but within the range of foreign literature values. The model was calibrated at major tributaries for a three-year period (2008 to 2010). The deviation values ranged from -31.5~1.6% of chlorophyll-a, -24.0~2.2% of T-N, and -5.7~34.8% of T-P. The root mean square error (RMSE) ranged from 4.3~44.4 ug/L for chlorophyll-a, -0.6~1.5 mg/L for T-N, and 0.04~0.18 mg/L for T-P, which indicates good calibration results. The operational water quality forecasting results for chlorophyll-a presented in this study were in good agreement with measured data and had an accuracy similar with model calibration results.

• 한국물환경학회지
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• 제30권6호
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• pp.673-682
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• 2014

A watershed model was constructed using Hydrological Simulation Program Fortran to predict the water temperature at major tributaries of Nakdong River basin, Korea. Water temperature is one of the most fundamental indices used to determine the nature of an aquatic environment. Most processes of an aquatic environment such as saturation level of dissolved oxygen, the decay rate of organic matter, the growth rate of phytoplankton and zooplankton are affected by temperature. The heat flux to major reservoirs and tributaries was analyzed to simulate water temperature accurately using HSPF model. The annual mean heat flux of solar radiation was estimated to $150{\sim}165W/m^2$, longwave radiation to $-48{\sim}-113W/m^2$, evaporative heat loss to $-39{\sim}-115W/m^2$, sensible heat flux to $-13{\sim}-22W/m^2$, precipitation heat flux to $2{\sim}4W/m^2$, bed heat flux to $-24{\sim}22W/m^2$ respectively. The model was calibrated at major reservoir and tributaries for a three-year period (2008 to 2010). The deviation values (Dv) of water temperature ranged from -6.0 to 3.7%, Nash-Sutcliffe efficiency(NSE) of 0.88 to 0.95, root mean square error(RMSE) of $1.7{\sim}2.8^{\circ}C$. The operational water temperature forecasting results presented in this study were in good agreement with measured data and had a similar accuracy with model calibration results.

• 식물분류학회지
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• 제44권2호
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• pp.136-163
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• 2014

본 연구는 강원도 골지천유역의 관속식물을 밝히고 주요 식물들의 분포를 조사하였다. 2012년 5월부터 2013년 10월까지 총 11회에 걸쳐 수행되었다. 그 결과 관속식물은 124과 420속 730종 8아종 78변종 6품종 3교잡종의 총 825분류군이 확인되었다. 이 중 한국고유종 34분류군, IUCN 평가기준에 따른 적색목록식물 34분류군, 식물구계학적 특정식물 165분류군이 조사되었다. 본 조사지에서 다른 지역에 비해 특이적으로 분포하는 식물은 101분류군이며, 이 중 호석회식물은 37분류군, 북방계식물은 64분류군이 확인되었다. 또한 수생식물 34분류군, 귀화식물 69분류군이 발견되었다.

• 생태와환경
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• 제45권2호
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• pp.150-157
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• 2012

Fish communities in river networks provide significant ecosystem services that will likely decline under future land use and climate change. We developed a model that simulates the consequences to multiple populations of one or more fish species-a meta-community-from multiple stressors across a river network. The model is spatially-explicit and age-structured, with three components: habitat suitability; population dynamics, including species interactions; and movement across a spatial network. Although this model is simple, it can form the basis of fisheries assessments and may be incorporated into an integrated modeling system for watershed management and prediction.