• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.4
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• pp.185-191
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• 2009

Few studies have attempted to analyze variations of daily maximum temperature in the summer whereas many studies have analyzed warming trends in other seasons with respect to greenhouse gases or urban heat islands. We analyzed daily maximum temperature data for the summer season (June to August) at 18 locations in South Korea from 1983 to 2007. Compared to the climatic normal (from 1971 to 2000), an average increase of $0.1^{\circ}C$ was found for the summer daily maximum temperature along with an increase of $0.61MJ\;m^{-2}$ in daily solar radiation. Approximately 65% of the annual variations of the summer daily maximum temperature could be explained by the solar radiance alone. Higher atmospheric transmittance due to lower aerosol concentration (especially of sulfur dioxide) is believed to have caused the recent increase in solar irradiance. Daily maximum temperature of the summer is expected to keep rising if the clean air activities are maintained in the future.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.449-449
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• 2023

유량은 도섭법, 보트법, 횡측선법, 교량법 및 부자법 등 다양한 방법으로 측정되는데, 이들 측정방법 모두 많은 수의 관측자를 필요로 한다. 이들은 하천에 직접 들어가서 측정하거나, 인공구조물인 교량과 재방에서 측정되는데, 도섭법, 보트법, 횡측선법이 전자이며, 고수위 및 고유속으로 하천에 들어가지 못하는 경우에는 교량법 및 부자법을 사용하여 유량을 측정한다. 최근 지구 온난화로 따른 이상 기후가 빈번히 발생하고 있으며, 이로 인한 많은 피해가 발생하고 있어, 하천 수위, 유속 모니터링에 대한 중요성이 더 커지고 있다. 2022년 1월부터 시행 중인 「중대재해처벌법」으로 집중호우 및 일몰 이후에는 안전상의 문제로 유량측정이 어려운 상황으로 필요한 시기에 유량 데이터를 확보에 제약이 있다. 이에 관측자 없이도 유량을 측정할 수 있는 방법을 이용하여 중대 재해의 위험성을 해소하고자 하였다. 유량측정 방법으로 설치 회수가 용이한 비접촉 방식에서 영상표면유속측정 방식과 레이더(전자파)표면 유속측정 방식 중, 집중호우 및 태풍 발생 중 가시성이 확보되지 않아도 측정이 가능한 레이더(전자파) 표면유속계를 이용한 다측점 유량측정 방법을 개발하였다. 비접촉 다측점 유량측정시스템 Master 1대에 8대의 Slave를 연결할 수 있어 총 9개의 측선을 측정할 수 있게 개발하였다. 특히, 하천 및 수로 등의 표면 유속을 비접촉으로 측정하고 하천 단면을 이용하여 유량측정이 가능한 장비로 별도의 수중 및 수상 주조물 작업이 필요 없고 장비의 손상 및 유실 가능성이 거의 없고 역류 상태에서도 측정이 가능하다. 유속은 24GHz의 레이더 주파수를 송수신하여 도플러 변이를 이용하여 측정하였고, 수위는 80GHz의 레이더 주파수를 사용하여 왕복 시간을 거리로 환산하여 측정하였다. 유량은 각각의 유속계에 단면을 입력해 놓으면 유속분포법, 중간단면적법 및 지표유속법을 적용하여, 각각의 측선에 대한유량과 총 유량을 산출하였다. 그 결과, 기존 방식 대비 상당한 개선 효과를 확인하였고, 향후 환경부 등 중앙부처의 수문조사 사업에서 그 역할이 기대된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.387-387
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• 2021

지구온난화와 기후변화로 인한 강우패턴의 변화는 가뭄, 홍수 등의 피해를 증가시키고 있다. 그 예로 2020년 여름 장마는 1973년 이후로 가장 긴 장마로 기록되었다. 이 장마는 제주도를 제외한 우리나라 전역에 평균 858 mm의 강수량을 발생시켰다. 장마로 인해 많은 지역에서는 도시침수와 하천범람이 발생하였으며 인적 그리고 물적인 피해를 입었다. 게다가 극한강수의 미래변화는 평균 강수량의 증가와 더불어 빈도도 증가하리라 전망한다. 따라서 심화되는 극한 기우 현상의 피해를 대비하기 위해서 수문순환이라는 시스템에 대한 이해가 필요하다. 구조방정식모형은 특정 현상에 대한 인과관계를 분석하기 위한 다변량 분석방법 중 하나로, 사회과학 분야에서 널리 사용되었으나 최근 자연과학 분야에서도 응용되고 있다. 구조방정식모형을 사용하여 관측된 자료가 이론 및 경험을 토대로 구축된 모형과 충분히 부합하는지를 검증할 수 있다. 구조방정식모형은 변수 간의 영향의 크기와 영향이 직접 혹은 간접적으로 작용하는지를 확인할 수 있고 모형에 대한 통계적인 평가로 연구모형이 수용 가능한지를 판단할 수 있다. 따라서 구조방정식모형을 사용하여, 수문순환의 모형을 구축하고 수문특성 간의 영향을 확인할 수 있다. 본 연구에서는 수문요소의 인과관계와 상관관계를 파악하기 위해 구조방정식모형을 적용하였고 2010년부터 2018년까지 설마천 유역과 청미천 유역의 연단위 강수량, 기저유출량, 직접유출량, 증발산량을 사용하였다. 각 유역에서의 수문특성과 수문요소 간의 관계를 확인하고 수문순환 모형을 구축/평가를 하였다. 그 결과, 서로 다른 유역이지만 비슷한 구조방정식모형을 갖는다는 것을 확인하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.364-364
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• 2021

최근 지구온난화에 따른 홍수 및 가뭄 재해의 피해는 심각해졌다. 그러므로 미래 재해로 인한 피해를 완화시키기 위한 수자원 계획 수립 및 관리의 중요성이 높아지고 있다. 전지구모형(General Circulation Model, GCM)은 기후 변화 연구에서 기후 요인의 변동을 조사하는데 널리 사용되어지고 있다. 본 연구에서는 기후 변화 시나리오를 고려하여 도시유역의 소유역 별 투수성포장 시설의 우선순위를 산정했다. 기후 변화 시나리오에는Representative Concentration Pathway(RCP)와 Shared Socioeconomic Pathway(SSP) 시나리오가 사용되었으며 CMIP5와 CMIP6의 GCM을 고려하였다. GCM을 이용하여 산정된 미래 월 강수량은 분위사상(Quantile Mapping)법의 비모수변환(Non-Parametirc Transformation)법 중 하나인 스플라인 평활(Smoothing Spline) 방법을 사용하여 편이보정 되었다. 연구대상지는 목감천 유역이 선정되었으며, 27개의 소유역에 대해 투수성포장 시설의 우선순위를 산정되었다. 우선순위 산정을 위한 평가 기준들은 Driving force-Pressure-State-Impact-Response(DPSIR) 모형을 기반으로 산정 되었다. 평가기준에 따른 27개의 소유역에 대한 값들은 통계청 및 국가수자원관리종합정보시스템(WAMIS), 편이보정 된 미래 강수량과 Storm Water Management Model(SWMM)을 이용한 유출분석 결과를 통해 도출했다. 평가기준들의 객관적 가중치 산정을 위해 엔트로피 방법을 이용했다. 최종적으로 목감천 소유역 별 투수성포장 시설의 우선순위 산정에는 다기준의사결정기법 중 하나인 TOPSIS방법을 사용했다. 산정 결과 DPSIR 모형을 기반으로 수문학적 요소에 큰 가중치를 부여한 경우 하류보다는 상류 유역에서 높은 우선순위를 확인했으며, 각 요소별 동일한 가중치를 주었을 때 하류 유역에 높은 우선순위가 집중되었다.

• Journal of the Korean Society of International Agriculture
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• v.31 no.4
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• pp.378-383
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• 2019

To determine whether FT-IR spectral analysis based on multivariate analysis for whole cell extracts can be used to discriminate papaya at metabolic level. FT-IR spectral data from leaves were analyzed by principal component analysis (PCA), partial least square discriminant analysis (PLS-DA) and hierarchical clustering analysis (HCA). FT-IR spectra confirmed typical spectral differences between the frequency regions of 1,700-1,500, 1,500-1,300 and 1,100-950 cm^-1, respectively. These spectral regions were reflecting the quantitative and qualitative variations of amide I, II from amino acids and proteins (1,700-1,500 cm^-1), phosphodiester groups from nucleic acid and phospholipid (1,500-1,300 cm^-1) and carbohydrate compounds (1,100-950 cm^-1). The result of PCA analysis showed that papaya leaves could be separated into clusters depending on different growth temperature. In this case, showed discrimination confirmed according to metabolite content of growth condition from papaya. And PLS-DA analysis also showed more clear discrimination pattern than PCA result. Furthermore, these metabolic discrimination systems could be applied for rapid selection and classification of useful papaya cultivars.

• Journal of the Korean Wood Science and Technology
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• v.36 no.1
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• pp.79-87
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• 2008

Many researchers have studied on rooftop greening that can be installed in abandoned spaces on a building roof. The most important issue in rooftop greening is the soil weight problem. The light greening materials are needed to solve this problem. Therefore, many alternative materials against the soil were investigated for rooftop greening. In this study, the waste wood chips and the waste paper slurry were evaluated as the lightweight vegetation foundation for rooftop greening. It also has a meaning for recycling of waste materials. The mixture ratio of waste wood chips to waste paper slurry for the board (the foundation of greening) was 60 to 40. The wet strength resin and the sizing agent were additionally added with different amount. After the forming of the board, physical and chemical properties were tested with the variation of wet strength resin and sizing agent. As the result of the test, the board with 15% of wet strength resin in the wet condition showed the highest strength. Futhermore, the moisture evaporation loss from the board surface with sizing agent was much lower than that from the board without sizing agent. Therefore, it was clear that the sizing agent was effective for water retention. The change of thickness in the wet condition was less than 1 mm, and it showed that the board is the predominant material on the dimensional stability. The average pH value of the board was ranged from 7.6 to 8.25.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.14-21
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• 2017

The extreme floods recently are have been attributed global warming, The development of a canal tunnel to prevent floods by making a bypass or undercurrent to flood discharge in a major flooding area is required because urban flooding in heavy rainfall occurs frequently, increasing the impermeability according to lack of capacity in sewage to urbanization by the existing urban basin. In this study, a numerical simulation was performed to support design standards for a multi-purpose waterway tunnel combined road tunnel of canal tunnel. The numerical simulation showed that the size of the friction loss occurring in the tunnel section of the same channel occurred more than the theoretically calculated frictional loss derived from the numerical simulations. This is probably due to the additional frictional loss caused by the change in the flow structure due to the geometry of the pipe when the shape of the channel is non-circular. The increase in friction loss was more pronounced in the laminar flow than in the turbulent flow. Depending on the shape of the conduit, the friction loss should be adjusted for accurate flow calculations. This result can provide the basin information about the design of flood by a pass conduit.

• Journal of the Korean Geographical Society
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• v.49 no.2
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• pp.245-263
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• 2014

This study tries to investigate the changes of mortality regarding heat waves which are usually considered as one of the most direct impacts of climate change. Based on 17 years data period (1994-2010), each city's threshold temperature and minimum mortality temperature are recognized. According to the results, minimum mortality temperature varies from 23 to $25^{\circ}C$, showing minimum temperature corresponding to $23^{\circ}C$ in Gangwondo and maximum temperature corresponding to $25.4^{\circ}C$ in Jeollabukdo and Major 7 city group. In case of threshold temperature, it ranges from 27 to $30^{\circ}C$. The cities having higher threshold temperatures tend to have large populations and vice versa. In addition, the cities having negative demographic vulnerability relatively have lower temperatures, representing correlation -0.44(p=0.06). The socio-economic-environmental vulnerability shows negative correlation with minimum mortality temperature(r=-0.36, p=0.032) and threshold temperature(r=-0.29, p=0.081). This paper represents that the number of mortality could increase rapidly and show large spatial differences in the number of mortality depending on various factors including natural, social, and economic factors of each region.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.1
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• pp.71-82
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• 2020

The existing transportation system, which is based on internal combustion engines, is rapidly being converted to electrification. Thus, eco-friendly public transportation with high transportation efficiency will continue to spread throughout the market in the near future. The purpose of this study is to compare and analyze the cognitive characteristics of passengers redgarding the technical and social factors of various public transportation means to help a successful introduction of eco-friendly public transit. Through a survey questionnaire (N=485), seven factors of seven transportation modes were evaluated and analyzed using principal component analysis. As a result, it is confirmed that potential passengers have high expectations for the eco-friendliness and city image of the eco-friendly buses. Also, it is confirmed that eco-friendly buses are superior in cleanliness and ride comfort than diesel buses. Given the study's results, this study identifies the cognitive characteristics of passengers regarding eco-friendly public transportation. We hope that these results will be used as basic information for image positioning and improved service with the use of eco-friendly transportation.

• Journal of the Society of Disaster Information
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• v.11 no.1
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• pp.73-88
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• 2015

Due to the cases of recent global warming and unusual weather etc., large-scale natural disasters such as typhoons, floods, snow damage occur frequently across the continents such as Southeast Asia and North America, South America etc. and risks of earthquakes and tsunami are also increasing gradually in Korea which has been regarded as a safe zone and disaster types are also being diversified such as typhoons, floods, heat waves, heavy snow and damage scale is also enlarged. In addition, due to geographical characteristics or lack of infrastructure, disasters tended to occur intensively around a specific region or city in the past but disasters occur throughout the country in recent years so preparation for disaster prevention has emerged as an urgent challenge issue. Therefore, considering that the plan of obtaining the effective feedback function of disaster Information is very important in the proactive and software aspects for disaster reduction, this paper analyzed this three aspects of contents, procedural and contextual aspects and proposed the plan. First, in the content aspect, building disaster prevention information communication Infrastructure, building urban and regional disaster prevention system, obtaining concurrency and sharing of information and second, in the procedural aspect, active utilization of ICT(Information and Communication Technology) of the prevention stage, disaster prevention information collection and analysis reinforcement of the preparation stage, improvement of decision-making structure and field command system of the response stage, recovery system related information promotion of the recovery stage were proposed as alternatives and finally, in the contextual aspect, if disaster prevention information is effectively managed through maintenance of disaster prevention information related systems, obtaining domainality by disaster prevention work, improvement of the ability to judge the situation, obtaining comprehensive and feedback function etc, it is considered to significantly contribute to reducing natural disasters.