• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.5
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• pp.62-72
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• 1995

공학분야에 널리 사용되고 있는 신뢰도 분석 방법 중에서 Monte Carlo simulation (MC), Mean-value First-Order Second-Moment Method(MFOSM), and Advanced First-Order Second-Moment(AFOSM) method들을 강물의 오염물질 농도와 수질기준치사이의 신뢰도 분석에 적용하였다. 미 환경 보건국에서 개발 보급한 QUAL2E를 이용하여 Mew Jersey에 위치한 Passaic강의 수질예측에서 4가지 주요인자(용존산소, 생물학적 산소요구량, 암모니아 그리고 조류)들이 정해진 수질기준치를 유지 할 수 있는 확률을 세가지 방법에 의해 추정한 후에 상호 비교하였다. MC방법에 의해 2,000회 simulation시켜서 그 결과가 시스템의 추계학적 성질을 잘 반영한 것으로 판단하여 비교기준으로 삼고 MFOSM과 AFOSM에 의해 추정한 결과와 비교하였다. MFOSM의 결과보다는 AFOSM의 결과가 전체적으로 MC의 결과에 더 근접하였으며, 이유는 AFOSM의 계산방법이 MFOSM의 선형근사로 인한 오차를 줄일 수 있었기 때문인 것으로 판단된다. MC방법의 결과와 다른 방법들의 결과사이의 차이가 입력 변수들이 평균값에서 멀어질 때가 많았는데 이는 MC의 경우 입력 변수들이 일정범위를 벗어나서 비현실적인 상황이면 model이 정지하는데, 다른 방법들은 simulation에 의한 것이 아니고 수학적인 계산에 의해서 신뢰도가 추정되기 때문에 이러한 상황이 반영될 수 없기 때문이다. 강물의 수질을 취급하는 공학적인 측면에서 보면, 이중에 가장 간편한 MFOSM이 많은 simulation이 필요한 MC나 계산방법이 상대적으로 복잡한 AFOSM에 비해 오차가 크지 않아서 이들을 대시하여 사용될 수 있다고 판단된다. 유래의 PAF가 분비된다는 것을 알 수 있었으며, 이러한 인자는 동결처리에서도 그 기능은 전혀 변하지 않는다고 본다. 이후에 있어서 mouse LIF의 첨가는 돼지의 수정란을 배반포 이후의 단계에까지 발달시킬 수 있었다. 있어서 더 적합한 것으로 판단되었다. 5. 개발된 모형은 논 관개의 물리적 측면과 관리목표 모두를 고려한 것으로 계산된 효율은 벼, 생육 각 단계에서의 효율 비교에 양호한 방법임을 알 수 있다.은 Sharpsburg 점질양토에 대한 S.C.S 한계허용치 10ton/ha/year 이내로 나타났다. 비처리구에서의 토양유실량은 평균 2.56ton/ha/year로 높게 나타난 반면 3개의 서로 다른 추리구인 비수구, 초생수로구 및 Bromegrass구에서는 각각 0.152, 0.192 및 0.290ton/ha/year로 낮은 결과를 가져왔다. 6. 평균 침전량에 대한 L.S.D. 검정 걸과 전시험구중 비처리구가 고도의 유의차를 나타낸 반면 비수구, 초생수로구 및 Bromegrass 목초구 간에는 아무런 유의차가 인정되지 않았다. 7. 농지보전 처리구인 배수구와 초생수로구는 비처리구에 비해 낮은 침두 유출량과 낮은 토양유실량을 나타내었다.구보다 14% 절감되는 것으로 나타났다.작용하는 것으로 사료된다.된다.정량 분석한 결과이다. 시편의 조성은 33.6 at% U, 66.4 at% O의 결과를 얻었다. 산화물 핵연료의 표면 관찰 및 정량 분석 시험시 시편 표면을 전도성 물질로 증착시키지 않고, Silver Paint 에 시편을 접착하는 방법으로도 만족한 시험 결과를 얻을 수 있었다.째, 회복기 중에 일어나는 입자들의 유입은 자기폭풍의 지속시간을 연장시키는 경향을 보이며 큰 자기폭풍일수록 현저했다. 주상에서 관측된 이러한 특성은 서브스톰 확장기 활동이 자기폭풍의 발달과 밀접한 관계가

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.2
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• pp.160-167
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• 2013

The influences of inland pollution sources nearJeokyang and Jangpoports following rainfall events on the bacteriological water quality and safety of commercial shellfish were investigated in the Changseon area, Korea. Stream flow rates exhibited 1.9- to 5.7-fold increases after rainfall events and then fell to 68~81% of that level after 24 h. The calculated impact area of inland pollution sources was 0.47 $km^2$ in the Jeokyangport area and 0.27 $km^2$ in the Jangpoport area at 24 h following 11 mm of rainfall. When the flow rate of inland pollution increased, the level of male-specific bacteriophage (MSB) decreased, and no MSB could be detected in seawater samples, whereas 30 PFU/100 g was detected in shellfish samples. Fecal coliform levels in seawater and shellfish samples did not exceed their respective tolerance levels (4.5 MPN/100 mL) and 130 MPN/100 g, respectively and thus complied with the standard for approved shellfish growing area. The sanitary conditions of areas adjacent to Jeokyang and Jangpoports under conditions of rainfall below 29 mm met the criteria for approved growing area under the United States National Shellfish Sanitation Program and the EC Regulations.

• Korean Journal of Environmental Biology
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• v.37 no.2
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• pp.204-216
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• 2019

To evaluate the biological integrity of aquatic ecosystems, we developed Korean multimetric diatom index (KMDI) using metrics that many researchers have been previously described, and compared to single-metric diatom index such as trophic diatom index (TDI) and diatom assemblage index to organic pollution (DAIpo). For the biological and environmental data, we investigated the epilithic diatoms, water quality and the land-use for 923 sites in Korean streams between 2013-2017, and estuaries between 2010-2017, respectively. Five appropriate metrics were selected according to the following steps; 1) extraction of 300 potential metrics (biological, chemical, physical, and geographical) based on previous references, of these, 2) 46 samples having high separation power were selected, 3) the selected metrics were each tested for variability, redundancy, and sensitivity to the environments, finally 4) construction of multi-metric diatom index comprising single type metrics such as TDI, DAIpo, % motile diatoms, % Achnanthes / (Achnanthes+Navicula), and % number of Gomphonema species. The biological integrity of the 233 sites from the Geum River basin were independently investigated using KMDI. Collectively, the new KMDI showed high sensitivity and explanatory power for environmental factors such as land-use, biochemical oxygen demand, total nitrogen, and electric conductivity. However, it had slightly higher biological integrity for the same sites as compared to single type diatom metrics. Finally, more data accumulation from all over Korea and the development of acceptable diatom metrics were required.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.4
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• pp.210-218
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• 2016

The pollutant removal efficiencies of stormwater runoff by settling were analyzed using field samples collected in 4 different raining events in a test bed installed in the Gwanpyung-Cheon stream in Daejeon. A 1.8 m high with 30 cm diameter cylindrical settling device was used for the settling test by measuring concentration of TSS, TP and TN for time and height. The pollutants removal rate was relatively high in the first 4 hours while 24 hours seem to be necessary to reach steady state in pollutant concentrations. However, there were no considerable differences in concentrations for height at a given time. This indicates most of particulate pollutant in the test seems to show independent settling with no interference to each other. Much part of particle sizes were distributed in the range of $10{\sim}100{\mu}m$. Average particulate fractions of TP and TN were estimated as 52.4% and 23.5%, respectively. This results explain why TN is difficult to remove by simple settling. This study indicates that a simple settling can provide effective method to remove significant amount of TSS and TP effectively and this can be used to protect urban river water quality.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.3
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• pp.177-188
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• 2012

This study was mainly focused on the development of GIS based decision support system to easily make mitigation scenarios and to conveniently simulate water quality for TMDL. The study area was the 31km section of upper Sapgyo stream in Geum river basin, and QUAL2E model was adopted. GIS DB was built through the collection of the data which includes point/non-point source attributes and various thematic maps. The amounts of discharged loads of BOD, T-N and T-P from unit watershed were estimated respectively. Finally, the system, which can operate water quality simulation through simply modifying their values, was developed. The hypothetical three mitigation scenarios were applied, thereby the most efficient mitigation scenario could be chosen by comparison of the results based on GIS. Therefore, it is expected that the developed system can facilitate the decision makers to select the best alternative through the analysis of the available BMPs. Also, it can be used to develop new scenarios using different methods and algorithms. In the future, more study need to be made to enhance its applicability in the perspective of developing mitigation scenarios through the management of individual pollutant sources and extending study areas.

• Korean Journal of Ecology and Environment
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• v.39 no.1 s.115
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• pp.100-109
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• 2006

This study evaluated the effects of water velocity, substrates, and phosphorus concentrations on the growth of filamentous periphytic algae (FPA) in the two types of artificial channel systems using treated wastewater. Controlled parameters included 5 ${\sim}$ 15 cm $s^{-1}$ for the water velocity; 10 and 20 mm wire meshes, natural fiber net, gravel and tile for the substrates: and 0.05 ${\sim}$ 1.0 mgP $L^{-1}$ for the P concentration. Algal growth rate of FPA was compared using both chi. a and dry weight change with time. Under the controlled water velocity range, the growth of FPA increased with the velocity, but the maximum growth rate was shown in the velocity of 10 cm $s^{-1}$. The substrate that showed the maximum growth of FPA differed between the artificial channel and indoor channel, due to the influence of suspended matters which caused the clogging of the meshed substrates. Under the controled range of P concentration, the growth rates of all three FPA species (Spirogyra turfosa, Oedogonium fovelatum, Rhizoclonium riparium) increased with the P increase, but they showed the differential growth rates among different P concentrations. The results of this study suggest that under the circumstance having an large amount of nutrients FPA develop the biomass rapidly and that even a little increase over the threshold velocity causes the detachment of filamentous periphytic algae. Thus, FPA dynamics in eutrophic streams, such as those receiving treated wastewater, seem to be sensitive to the water velocity. On the other hand, detached algal filaments could deteriorate water quality and ecosystem function in receiving streams or down-stream, and thus they need to be recognized as an important factor in water quality management in eutrophic streams.

• Korean Journal of Environmental Agriculture
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• v.19 no.4
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• pp.276-283
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• 2000

This study was carried out to investigate distribution of epilithic algal and chemical contents of irrigation water influencing in the Seomjin River from March to October in 1996 and 1997. In the water quality of the Seomjin River, the monthly average contents of $NH^+\;_4-N,\;SO_4\;^{2-}$ and $Cl^-$ showed the lowest peak in July and August while that of $NO_3-N$ showed the highest peak in June. The water quality of the Seomjin River was deteriorated by inflow of Yo-cheon and Sosi-cheon in the middle stream. The concentration of anions and cations of the Seomjin River was $Cl^->SO_4\;^{2-}>NO_3\;^->PO_4\;^{3-}\;and\;Ca^{2+}>Na^+>Mg^{2+}>K^+>NH_4\;^+$, respectively. The epilithic algal community identified 339 taxa consisting of 7 forma, 42 varieties and 290 species in 6 classes. In species composition, green algae and diatoms were heavily dominated which were evaluated 50.4% and 31.3% of total classification, respectively. In seasonal distribution, 219 species presented in summer but, 147 species were in winter. In this study, dominant species were Cocconeis placentula var. euglypta and Cosmarium furcatospermum in spering. Cyclotella meneghinasa and Synedra ulna, Scenedesmus ecornis in summer. Melosira varians, Achnathes minutissima in autumn and Gomphonema parvulum in winter were dominated. Finally, the dominant indices in this study have ranged 0.10-0.43.

• Korean Journal of Environment and Ecology
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• v.28 no.4
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• pp.432-441
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• 2014

April, 2005 to October, 2013. The collected species during the survey period were 17 species belonging to 6 families. Dominant species was Zacco koreanus(Relative abundance 59.9%) and subdominant species Pungtungia herzi(8.5%). Korea endemic species were 12, including Coreoleuciscus splendidus. The species of Hemibarbus mylodon was identified as natural monument, and Pseudopungtungia tenuicorpa and Gobiobotia brevibarba were endangered species. Water quality assessment of Gapyeong Stream, had lately maintained the rating of "very good" for nine years, based on the Ministry of the Environment standards notice. It was found that there was a tendency for populations which is Coreoperca herzi carnivorous species decreases, increases omnivorous species Zacco platypus. As a result of community analysis, dominant index was 0.58~0.86, diversity index was 0.94~1.77 and richness index was 0.99~2.39. As a result of using the Rarefaction curve, were analyzed occurrence species expected each year, number of species is estimated from a sample of 151 individuals, up to 12(2005) was at least 5(2007) species. The regression coefficient (b) in relation to length-weight on Z. koreanus population were annual average $3.29{\pm}1.11$, condition factor slope $0.0034{\pm}0.0021$, which maintained good growth condition and stabilized population.

• Journal of Korean Society of Forest Science
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• v.101 no.4
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• pp.686-694
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• 2012

This study was conducted to investigate that affect benthic macroinvertebrates for installed erosion control works at a mountain torrential stream. The survey was carried out six times from April 2007 to October 2008 at two points where erosion control works were installed and at a control point in the upstream with no such works. Variations in the community structure and cluster of benthic macroinvertebrates and ecological water quality were analyzed in the survey. From the six times survey, the identified benthic macroinvertebrates were 6,922 individuals belonged to 27 species, 24 families, 13 orders, 6 classes and 4 phyla. As the average results of three surveyed sites, the dominant species was Gammarus sobaegensis of Amphipoda. The species diversity index(H') showed the highest as 1.47 at Site 2 of the fourth survey and the lowest as 0.24 at Site 2 of the sixth survey. The evenness Index(EI) showed the highest as 0.823 at Site 2 of the fourth survey and the lowest as 0.194 at Site 1 of the fifth survey. The richness index(RI) showed the highest as 2.794 at Site 1 of the first survey and the lowest as 0.291 at Site 2 of the sixth survey. The ecological score of benthic macroinvertebrate community(ESB) and individual of EPT-group were declined during the survey period. The functional feeding group(FFG) showed the highest SH types during the survey period.

• Ecology and Resilient Infrastructure
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• v.10 no.3
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• pp.73-84
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• 2023

The objective of this study was to evaluate biodiversity and natural habitat environment of freshwater ecosystem. Our aim was therefore to produce a set of biodiversity and habitat indicators based on multi-parameters of water quality and biodiversity by analyzing the characteristics of the results by indicators. We selected four indicators a) anthropogenic disturbance, b) habitat diversity, c) biodiversity, d) ecosystem structure. The fishes cohabiting with Brachymystax lenok tsinlingensis were Rhynchocypris kumgangensis and Zacco koreanus. As a result of the anthropogenic disturbance evaluation, it was analyzed that vegetation embankment showed a more stable environment in the tributary than the main stream, and other disturbance was not confirmed As a result of the habitat diversity evaluation, it was analyzed that habitat evaluation index showed a high score of 200 more on average, showing an optimal habitat condition. As a result of the biodiversity evaluation, it was analyzed as a clean habitat condition with a high proportion of sensitive species, abundant dissolved oxygen, and little pollutants. As a results of the ecosystem structure, the ecological health condition metrics and appearance of endangered species showed large score deviation, but it was analyzed that the stream ecosystem health was generally excellent. There was a slight correlation between the habitat environment and the results of the nature habitat evaluation according to the appearance of the B. lenok tsinlingensis.