Contribution of Greening and High-Albedo Coatings to Improvements in the Thermal Environment in Complex Urban Areas

Song, Bonggeun,Park, Kyunghun Hindawi Limited 2015 Advances in meteorology Vol.2015 No.-

<P>The aim was to identify microclimate characteristics in relation to ground cover in green areas and the reflectivity of building coating materials. Furthermore, microclimate modeling of temperatures was conducted using ENVI-met, to analyze the effects of improved thermal environments based on increased green areas and increased reflectivity of exterior coatings. The accuracy of ENVI-met was validated through comparisons with field temperature measurements. The RMSE deviation of the predicted and actual field temperature values was 3–6°C; however, the explanatory power was as high as 60%. ENVI-met was performed for commercial and single residential areas that have high densities of artificial cover materials, before and after changes related to development of green areas and to increase in the reflectivity of coating materials. The results indicated that both areas exhibited distinct temperature reductions due to the creation of green spaces. When the reflectivity of the coating material was increased, a temperature increase was observed in all land-use types. Therefore, in order to improve the thermal environment of complex urban areas, it is necessary to improve green-area development and to use high-reflectivity ground and building cover materials, while taking into account the spatial characteristics of land-use types and their surrounding areas.</P>

Validation of ASTER Surface Temperature Data with<i>In Situ</i>Measurements to Evaluate Heat Islands in Complex Urban Areas

Song, Bonggeun,Park, Kyunghun Hindawi Limited 2014 Advances in meteorology Vol.2014 No.-

<P>This study compared Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) surface temperature data with<I>in situ</I>measurements to validate the use of ASTER data for studying heat islands in urban settings with complex spatial characteristics. Eight sites in Changwon, Korea, were selected for analyses. Surface temperature data were extracted from the thermal infrared (TIR) band of ASTER on four dates during the summer and fall of 2012, and corresponding<I>in situ</I>measurements of temperature were also collected. Comparisons showed that ASTER derived temperatures were generally 4.27°C lower than temperatures collected by<I>in situ</I>measurements during the daytime, except on cloudy days. However, ASTER temperatures were higher by 2.23–2.69°C on two dates during the nighttime. Temperature differences between a city park and a paved area were insignificant. Differences between ASTER derived temperatures and onsite measurements are caused by a variety of factors including the application of emissivity values that do not consider the complex spatial characteristics of urban areas. Therefore, to improve the accuracy of surface temperatures extracted from infrared satellite imagery, we propose a revised model whereby temperature data is obtained from ASTER and emissivity values for various land covers are extracted based on<I>in situ</I>measurements.</P>

Analysis of climate change impact on flow duration characteristics in the Mekong River

Lee Daeeop,Lee Giha,Song Bonggeun,Lee Seungsoo 한국수자원학회 2019 한국수자원학회논문집 Vol.52 No.1

본 연구에서는 기후변화에 따른 메콩강 유출변화 분석을 목적으로 하고 있다. HadGEM3-RA로 부터 생산된 동아시아 지역 RCP 4.5 및 8.5 시나 리오의 일 자료를 기반으로 편의보정을 통해 미래 기후변화 시나리오를 구축한 후, SWAT 모형을 이용하여 메콩강 주요지점인 Kratie(유역면적: 646,000 km2, 메콩강의 연평균 유량의 88%)에서의 유출변화 모의하고 유황분석을 수행하였다. 기후변화 분석 결과 Kratie 유역의 미래 강수량은 기준 년 연평균 강수량 대비 미래 년 기간의 연평균 강수량은 두 시나리오 모두 증가하는 것으로 분석되었으며 월별 강수량 변화 분석을 통해 6 월∼11월에 강수량의 증가가 비교적 크게 나타나며 특히 RCP 8.5 시나리오에서 강수량의 변동 폭 및 증가량이 크게 나타남을 확인하였다. 시나리 오별 월평균 최대 및 최소기온의 변화는 두 시나리오 모두 미래 기온의 상승을 전망하고 있으며 특히 RCP 8.5 시나리오의 온도증가 폭이 크게 나타 나는 것을 확인 하였다. 또한 하천유황변화 분석결과 유역의 유량변동성이 더욱 커질 것으로 분석되었으며 저수계수 값이 52∼57% 감소하고 갈 수계수 값이 67∼74% 감소하는 것으로 나타나 하천의 갈수상황이 지속되어 미래에 가뭄이 보다 심화될 것으로 분석되었다. The purpose of this study is to analyze the Mekong River streamflow alteration due to climate change. The future climate change scenarios were produced by bias corrections of the data from East Asia RCP 4.5 and 8.5 scenarios, given by HadGEM3-RA. Then, SWAT model was used for discharge simulation of the Kratie, the main point of the Mekong River (watershed area: 646,000 km2 , 88% of the annual average flow rate of the Mekong River). As a result of the climate change analysis, the annual precipitation of the Kratie upper-watershed increase in both scenarios compared to the baseline yearly average precipitation. The monthly precipitation increase is relatively large from June to November. In particular, precipitation fluctuated greatly in the RCP 8.5 rather than RCP 4.5. Monthly average maximum and minimum temperature are predicted to be increased in both scenarios. As well as precipitation, the temperature increase in RCP 8.5 scenarios was found to be more significant than RCP 4.5. In addition, as a result of the duration curve comparison, the streamflow variation will become larger in low and high flow rate and the drought will be further intensified in the future.

UAV 영상과 ENVI-met 활용 물리적 환경과 열적 환경 비교

김성현 ( Seounghyeon Kim ),박경훈 ( Kyunghun Park ),송봉근 ( Bonggeun Song ) 한국지리정보학회 2023 한국지리정보학회지 Vol.26 No.4

The purpose of this study was to compare and analyze diurnal thermal environments using Unmanned Aerial Vehicles(UAV)-derived physical parameters(NDVI, SVF) and ENVI-met modeling. The research findings revealed significant correlations, with a significance level of 1%, between UAV-derived NDVI, SVF, and thermal environment elements such as S↑, S↓, L↓, L↑, Land Surface Temperature(LST), and Tmrt. In particular, NDVI showed a strong negative correlation with S↑, reaching a minimum of -0.52** at 12:00, and exhibited a positive correlation of 0.53** or higher with L↓ at all times. A significant negative correlation of -0.61** with LST was observed at 13:00, suggesting the high relevance of NDVI to long-wavelength radiation. Regarding SVF, the results showed a strong relationship with long-wave radiative flux, depending on the SVF range. These research findings offer an integrated approach to evaluating thermal comfort and microclimates in urban areas. Furthermore, they can be applied to understand the impact of urban design and landscape characteristics on pedestrian thermal comfort.

레이저 용접의 자동차 램프 접합 적용을 위한 공정특성 연구

김태경(Taekyung Kim),정우영(Woyoung Jung),송봉근(Bonggeun Song),고주섭(Juseop Ko),김수원(Suwon Kim) 한국자동차공학회 2020 한국자동차공학회 부문종합 학술대회 Vol.2020 No.7

해수와 담수에서 점탄성을 갖는 그라우트재의 공학적 특성 평가

김욱기(Kim, Ukgie),조삼덕(Cho, Samdeok),박봉근(Park, Bonggeun),송병덕(Song, Byeongdeok),김주형(Kim, Juhyong) 한국지반환경공학회 2012 한국지반환경공학회논문집 Vol.13 No.6

일반적인 그라우팅 재료는 물속에서 재료 분리가 발생하여 수중 그라우팅 작업시 시공 품질 확보가 매우 어렵다. 최근에는 다양한 혼화제를 첨가하여 수중에서 재료분리가 발생하지 않는 수중 불분리성의 그라우팅 재료들이 개발되고 있다. 본 연구에서는 계면활성제계 개질제를 이용하여 수중에서 재료분리가 발생하지 않으면서도 유동성을 충분히 갖는 점탄성 그라우트재를 개발하고 실내시험을 통해 해수 및 담수에 수중 불분리성 그라우팅 재료와 일반 그라우팅 재료를 시공하였을 때의 공학적 특성을 분석하였다. 본 연구에서 개발한 수중 불분리성 그라우팅 재료는 일반 그라우트재와 비교하여 해수와 담수 상태에서 충분한 강도가 발휘되었으며 수중에서 재료 분리가 발생하지 않아 수중에서도 좋은 시공 품질을 확보할 수 있을 것으로 평가되었다. In general, it is critical that grout consistency permit the complete filling of void space without segregation of ingredients. Recently, the antiwashout agent is used on underwater grout materials for preventing the grout from the segregation in water. This study introduces a new type of antiwashout underwater and flowable grout material using viscous modifiers and its characteristics comparing with conventional grout materials in fresh and sea water. It is found that the antiwashout underwater grout both in fresh and sea water has enough strength and good resistance to segregation.

Water-Erasable Memory Device for Security Applications Prepared by the Atomic Layer Deposition of GeO₂

Yoon, Chang Mo,Oh, Il-Kwon,Lee, Yujin,Song, Jeong-Gyu,Lee, Su Jeong,Myoung, Jae-Min,Kim, Hyun Gu,Moon, Hyoung-Seok,Shong, Bonggeun,Lee, Han-Bo-Ram,Kim, Hyungjun American Chemical Society 2018 Chemistry of materials Vol.30 No.3

<P>We have investigated the atomic layer deposition (ALD) of GeO<SUB>2</SUB> thin films that dissolve in water rapidly and have excellent electrical properties for use in memory devices. The growth characteristics based on surface reactions during the ALD process are discussed by correlation with experimental results and atomistic theoretical calculation. Compared to sputtered GeO<SUB>2</SUB> films, the ALD-grown GeO<SUB>2</SUB> is perfect, pure, and water-soluble at room temperature and has better electrical properties for use as the dielectric layer in memory devices. The superior film properties of ALD GeO<SUB>2</SUB> are attributed to the higher film density, high purity, low roughness, and highly stoichiometric film composition. Finally, we demonstrate the fabrication of charge-trapping memory (CTM) devices with ALD GeO<SUB>2</SUB>, and that the electrical information stored in the CTM can be eliminated immediately by exposure to one droplet of water at room temperature. Thus, ALD GeO<SUB>2</SUB> could find widespread application in the fabrication of secure memory devices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2018/cmatex.2018.30.issue-3/acs.chemmater.7b04371/production/images/medium/cm-2017-04371t_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm7b04371'>ACS Electronic Supporting Info</A></P>

노후도로 관리를 위한 노면 평탄성 감지장치 활용 방안

최민재(Choi, Min Jae),김태훈(Kim, Tai-Hoon),김현주(Kim, Hyun Ju),송봉근(Song, Bonggeun) 한국방재학회 2017 한국방재학회논문집 Vol.17 No.4

본 연구에서는 울산광역시의 석유화학단지 진출입 도로를 대상으로 노후도로 관리를 위한 노면 평탄성 감지장치의 활용방안에 대해 알아보았다. 노면 평탄성 감지장치는 주행 계측을 통해 차량 충격값(G-value)과 속도, 노후지점의 좌표의 정보를 수집할수 있다. 노면 평탄성 감지장치를 활용한 결과, 노후지점은 총 194개가 탐지되었다. 또한 2차선 보다는 1차선 도로에서 노후지점이 다소 많게 측정되었다. 또한, 산업단지 인근의 순방향 2차선 도로는 노후지점이 18개로 가장 많아 도로 노후도가 취약한 것을 알 수 있었다. 본 연구의 노면 평탄성 분석결과는 노후도로의 효율적 유지․보수 등 관리를 위한 우선순위 설정에 활용될 수 있을 것으로 판단된다. The purpose of this study is to investigate the usage of the equipment detecting pavement smoothness focused on roadways in Ulsan Metropolitan City. The road smoothness detection equipment can collect G-value, speed, and coordinates of deteriorated positions while driving. The results of this study show that a total of 194 deteriorated points were detected, and the condition of inner lane was severe than outer lane. The worst severest area was the forward outer lane road near industrial complex and had 18 deteriorated points. Based on the results we found that the equipment is worth for the effective road management and it is, therefore, expected to be used the maintenance system of deteriorated road through continuous monitoring.