The Effects of Tree Species on Soil Organic Carbon Content in South Korea

Cha, Ji‐,Yeon,Cha, YoonKyung,Oh, Neung‐,Hwan American Geophysical Union 2019 Journal of geophysical research. Biogeosciences Vol.124 No.3

The relative importance of water temperature and residence time in predicting cyanobacteria abundance in regulated rivers

Cha, YoonKyung,Cho, Kyung Hwa,Lee, Hyuk,Kang, Taegu,Kim, Joon Ha Elsevier 2017 Water research Vol.124 No.-

<P><B>Abstract</B></P> <P>Despite a growing awareness of the problems associated with cyanobacterial blooms in rivers, and particularly in regulated rivers, the drivers of bloom formation and abundance in rivers are not well understood. We developed a Bayesian hierarchical model to assess the relative importance of predictors of summer cyanobacteria abundance, and to test whether the relative importance of each predictor varies by site, using monitoring data from 16 sites in the four major rivers of South Korea. The results suggested that temperature and residence time, but not nutrient levels, are important predictors of summer cyanobacteria abundance in rivers. Although the two predictors were of similar significance across the sites, the residence time was marginally better in accounting for the variation in cyanobacteria abundance. The model with spatial hierarchy demonstrated that temperature played a consistently significant role at all sites, and showed no effect from site-specific factors. In contrast, the importance of residence time varied significantly from site to site. This variation was shown to depend on the trophic state, indicated by the chlorophyll-a and total phosphorus levels. Our results also suggested that the magnitude of weir inflow is a key factor determining the cyanobacteria abundance under baseline conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Temperature and residence time were important predictors of cyanobacteria in rivers. </LI> <LI> The importance of temperature was universal, not affected by site-specific factors. </LI> <LI> The importance of residence time was affected by the trophic state of the site. </LI> <LI> Baseline cyanobacteria abundance was positively associated with weir inflow. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

자료기반 물환경 모델의 현황 및 발전 방향

차윤경 ( Yoonkyung Cha ) 한국물환경학회 2020 한국물환경학회·대한상하수도학회 공동 춘계학술발표회 Vol.2020 No.-

The data deluge, increased computing power, and advances in analytical methods have all made data-driven approaches more applicable to various academic disciplines. Accordingly, these approaches have been increasingly adopted in water quality and ecological studies to model freshwater aquatic systems. A systematic review of the literature was performed to analyze the long-term changes in the relative number of data-driven modeling studies (in comparison to process-based modeling studies) and temporal patterns of frequently used methods within the data-driven modeling framework. Also, these trends in South Korea were compared with the global trends. Both advantages and potential challenges involved with data-driven modeling and how these have been addressed by previous studies were discussed. Furthermore, the motivations for exploiting data-driven approaches, which are expected to prosper with the emergence of new sources and types of data, toward the effective management of aquatic systems were highlighted.

인공지능 기반 수생태 예측 모델 해석력 향상 기법 연구

차윤경(YoonKyung Cha),고병건(ByeongGeon Go),김영우(YoungWoo Kim),신지훈(Jihoon Shin),박영석(youngSeuk Park) 대한환경공학회 2020 대한환경공학회 학술발표논문집 Vol.2020 No.11

아미동 산동네의 형성과 문화변화

차철욱(Chulwook Cha),공윤경(yoonkyung Kong),차윤정(Yunjung Cha) 韓國文化歷史地理學會 2010 문화 역사 지리 Vol.22 No.1

본 연구는 아미동 산동네의 형성과정을 통해 공간과 문화의 변화를 고찰하고자 하였다. 이곳은 일본인 공동묘지와 화장장이 있던 곳으로, 산(生)사람의 삶터가 아니라 죽은 자의 공간이었다. 하지만 한국전쟁으로 삶터를 잃은 피난민이나 철거와 화재 등으로 쫓겨 온 이주민들이 죽은 자의 공간으로 모여들어 아미동 산동네를 만들었다. 산복도로보다 높은 해발 100m 이상의 고지대에 위치한 아미동은 천막에서 시작하여 현재 판잣집, 슬레이트집, 조적조(양옥) 주택까지 다양한 주거형태가 공존하고 있다. 가파른 경사지에 주택이 밀집되어 있기 때문에 열악한 주거환경을 보이고 있다. 문화적 변화를 언어를 중심으로 살핀 결과, 출신지의 언어적 특성은 흔적으로만 남아 있고 대부분의 언어는 부산 지역어로 동화되는 현상을 보이고 있었다. 이러한 동화 현상의 원인은 역사.사회.문화적으로 소외되어 공동묘지로 이주할 수밖에 없었던 이주민의 삶과 소통을 단절시킬 수밖에 없었던 공간적 특징, 그리고 서로를 소외시켰던 이주민들 간의 의식 등이다. This study aims to consider changing of space and culture through a formation of Ah-mi dong mountain town community. Where it was a Japanese cemetery and crematory, not only living space for alive people but also death space for dead people. However, the people, evacuees by Korean war and immigrants by demolitions and fires and so on, had come to space of death people and have built UP Ah-mi dong mountain town community. In Ah-mi dong, where it lies in hill side various housing modalities coexist from tents and Plank houses to slate-roofed houses and Masonry houses. As the housing in this area close roof by roof in steep incline, therefore residential environment is inferior. As a result of analysing cultural changes centered on language, linguistic characteristics by one’s native places remain only traces, while most languages assimilate with Pusan area language. The reason the assimilation happen seems like lives of settlers who did not have any other choices, shunned from other socio-culturally and historically, spatial features that could not help shunning with communication from outside and awareness between settlers who were shunned each other.

Production of Urban Debris Flow Hazard Maps: Case study in Daegu, Korea

Yoonkyung Park,Mookwang Sung,Wooyoung Cha,Sangdan Kim 한국방재학회 2017 Journal of Disaster Management Vol.2 No.1

Abstract : This study is classified as a possible indirect and direct damage caused by landslides in Daegu and produces urban debris flow hazard maps. The range of urban debris flow is identified in the spatial scale of census output areas using Flow-R forced by landslide hazard maps. After dividing the type of building in each census output area into two (reinforced concrete structures and non-reinforced concrete structures), the physical hazard is assessed in applying the corresponding vulnerability function. An index-based model is proposed to represent indirect damages, using this model application, the socioeconomic hazard is also assessed. The urban debris flow hazard is finally assessed by integrating two hazard assessments. The assessment maps produced in this study can be used in identifying debris flow risk regions in the Daegu metropolitan and are expected to serve as basic data to prepare debris flow protection facilities. Abstract : This study is classified as a possible indirect and direct damage caused by landslides in Daegu and produces urban debris flow hazard maps. The range of urban debris flow is identified in the spatial scale of census output areas using Flow-R forced by landslide hazard maps. After dividing the type of building in each census output area into two (reinforced concrete structures and non-reinforced concrete structures), the physical hazard is assessed in applying the corresponding vulnerability function. An index-based model is proposed to represent indirect damages, using this model application, the socioeconomic hazard is also assessed. The urban debris flow hazard is finally assessed by integrating two hazard assessments. The assessment maps produced in this study can be used in identifying debris flow risk regions in the Daegu metropolitan and are expected to serve as basic data to prepare debris flow protection facilities.

AR5 RCP 시나리오에 따른 금호강 유역 수문변화지표 분석

차우영(Cha, Wooyoung),이옥정(Lee, Okjeong),김상단(Kim, Sangdan),박윤경(Park, Yoonkyung) 한국방재학회 2017 한국방재학회논문집 Vol.17 No.4

기후변화로 하천 유역의 유량 및 수문현상이 변화될 것으로 예측되고 있으며, 이러한 유량변화에 대한 분석은 수생태계 및 수자원 관리에 있어서 중요한 요소 중 하나이다. 따라서 본 연구에서는 AR5 RCP 시나리오를 바탕으로 SWAT를 이용하여 금호강 유역의 미래 유량을 모의하여 기후변화에 따른 수문변화지표(IHA)를 살펴보았다. IHA 분석 결과, 여름철 및 겨울철의 수생태계 서식 공간 가용성 증가로 인해 현재보다 수생태계가 받는 공간제약에 따른 스트레스는 감소할 것으로 예상되었으나, 극한사상이 발생하는 시기 및 지속시간의 변화, 고유량 및 저유량의 빈도 및 지속시간의 변화, 일 하천 유량의 변동폭 등이 현재와는 많이 달라지는 것으로 분석되어 이에 따른 수생태계가 받는 스트레스는 현재보다 증가할 것임을 살펴볼 수 있었다. It is predicted that the flow and hydrological phenomena of the river basin will be changed due to climate change and analysis of this flow change is one of the important factors in the water ecosystem and water resource management. Therefore, in this study, we investigated indicators of hydrological alteration (IHA) according to climate change by simulating the future flow of the Geumho River basin using SWAT based on the AR5 RCP scenarios. As a result of the IHA analysis, it is expected that the stress due to the space constraint of aquatic ecosystem will decrease due to the increased availability of the ecosystem habitat in summer and winter. However, changes in the timing and duration of extreme events, frequency and duration of high and low flow rates, and fluctuations in daily river flow are much different from those of the present. Therefore, it can be seen that the stress of the aquatic ecosystem will increase more than the present.

RCP 4종을 이용한 부산지역의 극치해수면 상승 전망

차우영(Cha, Wooyoung),박윤경(Park, Yoonkyung),이옥정(Lee, Okjeong),김상단(Kim, Sangdan) 대한토목학회 2016 대한토목학회 학술대회 Vol.2016 No.10

Matlab-SWAT 연동모델을 이용한 금호강 유량 모의

박윤경(Park, Yoonkyung),이정훈(Lee, Jeonghoon),차우영(Cha, Wooyoung),김상단(Kim, Sangdan) 대한토목학회 2016 대한토목학회 학술대회 Vol.2016 No.10

금호강 하천수질의 비점오염물질 기여율 분석

박윤경(Park, Yoonkyung),차우영( Cha, Wooyoung),정경민(Jeong, Gyeongmin),김상단(Kim, Sangdan) 한국방재학회 2017 한국방재학회 학술발표대회논문집 Vol.2017 No.-