• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1393-1397
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• 2005

홍수유출을 저감시키기 위해서 유역의 저류기능을 강화시킬 수 있는 댐 건설은 이수적인 측면에서 안정적인 용수공급을 보장해주는 수단으로 겸용되어 왔으며, 특히 다목적댐이 건설되면서 하도의 첨두홍수유출량을 줄이는데 크게 기여해 왔다. 하지만 그로 인해 물의 흐름이 막히는 정체수역이 증가하고 있으며, 생활오수, 산업폐수의 발생은 정체수역에서의 영양염류 부하량을 증가시켜 부영양화를 초래하고 있다. 수생식물은 태양빛을 받아 광합성 작용을 하여 수중에서 성장하면서 수중의 유$\cdot$무기물질을 영양소로 섭취함으로써 수질을 정화시키는 작용을 하게 된다. 영양염류 부하량이 큰 정체수역의 오염된 물은 식물의 성장활동에 의해서 어느 정도 정화시킬 수 있으며, 이와 같이 수중에 식물을 식재하기 위해서는 식물이 하상에 쉽게 그리고 지속적으로 성장하고 번식활동을 할 수 있는 여건이 필요하다. 따라서 본 연구에서는 Mattress/Filter를 정체수역에 설치함으로써 이러한 식물의 성장과 번식을 도와줄 수 있는 환경조건을 제안하였다. 연구결과, Mattress에 식재한 갈대, 줄 및 애기부들의 피도는 $60-80\%$ 정도로 나타났다. 각 Mattress의 식물군집에는 초기 식재한 식물의 우점도가 가장 높았으나 갈대와 줄 군락의 경우 다른 종이 많이 출현하는 것으로 나타났다. 갈대 군락에서는 갈대가 크게 우점하였으나 그 외에 돌피, 하늘지기, 여뀌바늘 등이 우점하는 것으로 나타났다. 또한 줄 군락에서는 역시 줄이 크게 우점하였으나 방동사니, 돌피, 조개풀 등이 출현하였다. 애기부들 군락에서는 애기부들외에 세모고랭이와 미국가막사리 두가지 종만 출현한 것으로 나타났다. 갈대와 줄 군락의 출현 종수는 각각 7과 11이었으며, 다양도지수가 1.67, 2.18로 식물다양성이 크게 증가한 것으로 나타났다. 수질은 BOD 10mg/L, TN 15mg/L, TP 2.0mg/L이하로 이를 유등천 상류부에 공급할 경우 유등천의 수질은 BOD 6.7mg/L, TN 9.80mg/L, TP 0.90mg/L를 나타낼 것으로 예측된다. 고도처리시설의 도입 후 금강 합류점에서 갑천의 예측 BOD는 7.4mg/L로 현재 9.0mg/L에 비하여 개선되지만 이는 금강수계 오염총량 관리계획의 시$\cdot$도 경계지점 목표수질인 5.9mg/L를 만족시키지 못하므로, 이를 만족시키기 위해서는 방류수 BOD 7.2mg/L이하로 처리해야 할 것으로 판단된다.which support only concepts or image features.방하는 것이 선계기준에 적합한 것으로 나타났다. 밸브 개폐에 따른 수압 변화를 모의한 결과 밸브 개폐도를 적절히 유지하여 필요수량의 확보 및 누수방지대책에 활용할 수 있을 것으로 판단된다.8R(mm)(r^2=0.84)$로 지수적으로 증가하는 경향을 나타내었다. 유거수량은 토성별로 양토를 1.0으로 기준할 때 사양토가 0.86으로 가장 작았고, 식양토 1.09, 식토 1.15로 평가되어 침투수에 비해 토성별 차이가 크게 나타났다. 이는 토성이 세립질일 수록 유거수의 저항이 작기 때문으로 생각된다. 경사에 따라서는 경사도가 증가할수록 증가하였으며 $10\% 경사일 때를 기준으로 $Ro(mm)=Ro_{10}{\times}0.797{\times}e^{-0.021s(\%)}$로 나타났다.천성 승모판 폐쇄 부전등을 초래하는 심각한 선천성 심질환이다. 그러나 진단 즉시 직접 좌관상동맥-대동맥 이식술로 수술적 교정을 해줌으로써 좋은 성적을 기대할 수 있음을 보여주었다.특히 교사들이 중요하게 인식하는 해방적 행동에 대한 목표를 강조하여 적용할 필요가 있음을 시사하고

• Journal of Environmental Impact Assessment
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• v.32 no.4
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• pp.251-259
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• 2023

This study was conducted for the purpose of the basic direction for the new regulations and categories of Ruralism changing in the new era. To this end, the results of Delphi analysis and AHP analysis by dividing it into the definition, criteria, scope and component items of Ruralism based on systematic literature review are as follows. First, through studies representing most rural areas, it was found that Ruralism was the most problematic keyword and most of the studies did not cover it as they were studying various ranges of rural areas. Second, the Delphi survey was able to derive keywords that can be used as evidence for item classification and clear concept establishment for the regulation and category setting of Ruralism. Third, through the hierarchical decision-making method, it was found that landscape factors are the most important thing in forming Ruralism as well as deriving priorities that can be a baseline for each item. This study is meaningful in providing a minimum baseline as basic data for establishing the concept of Ruralism, and it is believed that future-oriented Ruralism can be established if reviews are added from various perspectives to overcome limitations dependent on expert groups.

• The Korean Journal of Ecology
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• v.22 no.1
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• pp.1-6
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• 1999

The author studied the soil microarthropoda's fauna, vertical distribution, seasonal fluctuation, and the relationship between the number of soil microarthropoda and environmental factor(pH) in survey area. 3949 soil microarthropoda were collected in survey area. They included Arachnida(48.6%), Collembola(23.5%), Hymenoptera(l9.9%), and Isoptera, etc. Fresh length was the longest(1l3.6 mm) in broad-leaf forest on Mt. Chilgap which is non-industrial complex area, and the shortest(46.8 mm) in pine forest at Yochon industrial complex. The population density of soil microarthropoda was the highest in summer and the lowest in winter. The number of soil microarthropoda was higher in Mt. Keryong and Chilgap, non-industrial complex area, than Yochon and Daesan, industrial complex area. The number of soil microarthropoda increased from spring to summer and decreased from autumn to winter. Vertically, soil microarthropoda were more abundant in the second layer subsoil(0∼5 cm) in spring, in the first layer(5∼10 cm) in summer and autumn, and in the third layer(0∼15 cm) in winter. Diversity index was higher in non-industrial area(1.02) than industrial complex area(0.73). Biodiversity index was the highest in the second soil layer, in pine forest on Mt. Keryong(l.60) and the lowest in the third soil layer, in broad leaf-forest, at Daesan industrial complex(0.24).

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.47-47
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• 2018

붉가시나무는 기후변화에 따라 분포 확산이 예측되고 목재로서의 이용가치가 증가하고 있다. 본 연구는 국내에서 붉가시나무의 자원량 및 생육환경을 파악하기 위하여 국내 분포 및 자생지의 식생구조를 분석하였다. 분포 범위 조사 결과, 제주도를 비롯한 남해안의 도서지역에 주로 분포하는데, 제주도 남부지역 약 200~800m에 분포하며 가거도, 완도, 진도 등에 주로 분포하였다. 지역별 자생지의 입지분석 결과, 교목층의 수고는 제주도에서 17.3m로 가장 높고 가거도의 경우 11.3m로 가장 낮았다. 또한 가거도 자생지의 경우 노출암 비율 70.7%, 평균 경사도 약 $30^{\circ}$로 경사가 매우 급하고 토양층이 가장 빈약하였다. 반면, 제주도에서는 계곡 사면이나 완만한 경사의 산록지대에 주로 분포하였다. 자생지의 식생구조를 파악하기 위하여 수종별 평균중요도지수를 산출한 결과, 교목층에서는 붉가시나무가 가장 높았다. 아교목층의 평균중요도지수는 제주도, 완도, 진도 자생지의 경우 동백나무가 각각 150.93, 83.54, 91.38로 가장 높았는데 이는 동백나무의 밀도가 상대적으로 높았기 때문이다. 반면 가거도 자생지에서는 붉가시나무의 평균중요도지수가 66.55로 가장 높게 산출되었다. 자생지 내 수종의 흉고직경에 따른 수고의 분포는 제주도, 진도, 완도 자생지의 경우 붉가시나무와 기타 수종이 전체 층위에서 고르게 분포하였지만 가거도 자생지에서는 상층일수록 경쟁 종없이 단일종이 분포하는 단순림으로 나타났다. 이 같은 단순림에서는 일시적인 교란에 의해 상층 개체가 없어지면 안정적으로 후대 개체를 생산할 수 없기 때문에 숲 가꾸기와 같은 적극적인 조절이 필요한 것으로 판단된다. 종다양도지수 분석결과, 층위가 높을수록 균재도가 낮게 나타났다. 이와 같은 연구결과는 붉가시나무림의 조성이나 안정적 유지 등 인위적 조절을 위한 기초 자료로 활용 할 수 있을 것으로 판단된다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.2
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• pp.75-82
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• 2009

This paper proposes a method which increases the linearity using an improvement mechanism of Doherty power amplifier and compensates the decrement of efficiency due to improvement of linearity. To verify the method, a 20W power amplifier is designed and implemented. Compared with 2-way Doherty power amplifier, the implemented 3-way Doherty power amplifier with class F shows improved linearity about 10dBc and efficiency about 1.5%. Also, efficiency characteristic has been improved about 3.5% compared with the 2-way Doherty power amplifier while maintaining linearity. This results show that the proposed 3-way Doherty power amplifier with class F is shown to be adequate for improvement of efficiency and linearity. It is expected that the proposed amplifier can be used for various wireless communication system amplifiers.

• Korean Journal of Environment and Ecology
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• v.25 no.3
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• pp.378-388
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• 2011

This study was done to classify the vegetation structure and ecological characteristics in Nakdong-jeongmaek. Therefore, we set up 34 plots($100m^2$) in 9km range. As a result of vegetation analysis, the vegetation of Seongsi valley was classified into the type of 6 communities i.e. Pinus densiflora community, Quercus variabilis community, Q. mongolica community, Q. serrata community, Betula schmidtii community, Larix leptolepis community. The average number of species and individuals were ranged from 8.5~10.5 and 27.5~75.6 respectively. Species diversity index(H') of groups were ranged from 0.6061~0.8736 per units, and it was highest and lowest in B. schmidtii and P. densiflora communities respectively. Similarity index of groups were slightly low. It was low in P. densiflora community, Q. mongolica community and L. leptolepis community, and lowest in Q. variabilis-Q. mongolica community.

• Korean Journal of Environment and Ecology
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• v.22 no.5
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• pp.521-529
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• 2008

This research conducted a survey on waterbirds visiting this area four times by season from February to October in 2007 to look into the habitat use of waterbirds, to do a value and grade testing of the tidal flat by dividing the foreshore on Muan Bay located in Jeollanam-do into four areas (Dongam, Guro, Bokryong and Wangsan tidal flats). The survey results revealed that there existed a total of 15,755 individuals of 54 species including 2 species of grebes, 7 species of herons, 7 species of dabbling ducks, 6 species of diving ducks, 20 species of waders, 3 species of gulls and 9 other species and this survey also observed 9,291 individuals of the wading birds as a dominant group on Muan Bay. In these classified groups, the gulls and waders were observed to mostly use Dongam tidal flat as their habitat, while the group using Guro tidal flat as their habitat was mostly grebes, dabbling and diving ducks. As a result of UPGMA clustering analysis in consideration of the species and number of individuals, there appear the close similarities between Dongam and Bokryong tidal flats and so do Guro and Wangsan tidal flats. Taking a look at the grading of tidal flats by setting up ecological indexes, such as diversity index, abundance index, and dominance index, etc. legally reserved species and maximum number of individuals as a standard, the rank for the value and importance degree of Bokryong tidal flat appeared higher than that of the other three tidal flats. Like this, the gradation of tidal flats according to waterbirds are judged to able to suggest objective data on the issue of proper judgment and designation of valuable tidal flat areas and its subsequent effective preservation and management.

• Korean Journal of Environmental Biology
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• v.40 no.2
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• pp.172-186
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• 2022

Benthic macroinvertebrates are important ecological and environmental indicators as primary or secondary consumers, and therefore are widely used in the evaluation of aquatic environments. However, there are no comprehensive river ecosystem monitoring surveys that link the major physicochemical water quality items with benthic macroinvertebrates in urban streams. Therefore, this study investigated the distribution characteristics of benthic macroinvertebrates and physicochemical water quality items (17 items) in Yangjaecheon and Yeouicheon from 2019 to 2020. At the same time, by applying Spearman's rank correlation analysis and nonmetric multidimensional scaling (nMDS) analysis in the water quality data and biotic index, we tried to provide basic data for diagnosing the current status of river ecosystems in major urban rivers in Seoul. Based on the study results, a total of 39 species and 3,787 individuals were identified in Yangjaecheon, the water quality(based on BOD, TOC, and TP) of Yangjaecheon was higher than Grade Ib(good), and the BMI using benthic macroinvertebrates appeared as Grade C(normal) at all the sites. In Yeouicheon, a total of 51 species and 4,199 individuals were identified, the water quality(based on BOD, TOC, TP) was higher than Grade Ib(good) similar to Yangjaecheon, and the BMI of both Upstream and Saewon bridge was Grade B(good), while Yeoui bridge was Grade C(normal). Overall, analysis results for the distribution of benthic macroinvertebrates by a nonmetric multidimensional scaling method showed no significant difference between the two streams (p=0.1491). Also, significant environmental variables related to benthic macroinvertebrates distribution were determined as water temperature and DO. On the other hand, the results of the correlation analysis between biotic index and major water quality items confirmed that R1 and BMI could be used for on-site urban river water quality evaluation.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.103-109
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• 2007

To investigate the effects of artificial vegetation island (AVI) on fish distribution, we compared fish fauna from artificial vegetation island (AVI) area, which installed in 2000, natural vegetation area (NVA) and vegetation-free area (VFA) at Kyungan Stream area of Lake Paldang from Jul. to Nov., 2005. Results showed that 11 families 23 genera 24 fish species were distributed in the AVI and NVA. Squalidus japonicus coreanus, a small-size fish which generally lives at the downstream, dominated absolutely in the individual numbers. However, only 6 families 11 genera 12 species of fishes caught at the VFA, and dominant fishes were Hemibarbus labeo and Erythroculter erythropterus, a medium to large-size migratory fishes which live in mid-depth of water column. The dominance index was high at the AVI (0.778) and NVA (0.868), whereas the diversity index and evenness index were high at the VFA. Fish distribution at AVI was similar to that of the NVA in numbers of species, indicating that the AVI could playa role as spawning and inhabitation zone to a variety of fishes. We believe that AVI may be used for a restoration of the damaged and disturbed littoral ecosystem.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2B
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• pp.193-203
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• 2011

With the recent growth of environmental and ecological interests, various river restoration and habitat environment creation projects are being carried out. For this, the estimation of the habitat flow discharge is important. In U.S. and Europe nations, The instream flow incremental methodology (IFIM) has been used to estimate the habitat discharge. IFIM is the method that can be applied to evaluate the flow discharge for the suitable habitat. To use the IFIM in river, a habitat suitability index(HSI) for the target organism is needed. However, HSIs for only two species of Zacco platypus and Zacco temminckii were proposed from the field monitoring. Thus, for the estimation of the ecological flow rate for a group of fish, the development of the HSIs for various fish are necessary. In this study, physical data such as water level and flow rate, chemical data such as acidity and dissolved oxygen, and life data such as fish types and population are collected in Keum river watershed. Based on the 2,736 field data, HSIs for the following 6 fish are developed: Zacco platypus, Zacco temminckii, Microphysogobio yaluensis, Coreoleuciscus splendidus, Pungtungia herzi, Pseudogobio esocinus. Through the comparison with HSIs in the literature, the developed HSIs are modified. Also, the limits of Froude number, pH, and DO for 6 fish are proposed. The HSIs developed in this study can be utilized as a essential data for performing river project evaluations.