• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2016년도 학술발표회
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• pp.329-329
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• 2016

Rapid urbanization has taken environmental toll on the surrounding which can be witnessed by the advent of global warming and climate change. Driven by environmental needs, Green Building Index (GBI) was established in Malaysia to drive initiative to lead the property industry towards becoming more environmental friendly. Green roofs (roof with vegetated cover) as one of the assessment criteria of GBI, are gaining attention in the Malaysian society as a versatile new environmental friendly mitigation technology. This paper evaluates the qualitative and quantitative performances of an extensive green roof at Humid Tropics Centre under local tropical climate. Simulations showed that the extensive green roof system could reduce the peak discharge up to 26% in relation to impervious brown roof. Its reduction ability decreased for storms with intense rainfall. Increment of pH was observed for the green roof runoff and the runoff water quality ranged between class I and II under Water Quality Index (WQI). High concentrations of phosphate were noticed in the runoff samples and substrates (fertilized planting soil) might be the potential contributor. Findings indicate that there was a reduction of around $1.5^{\circ}C$ for indoor temperature of the building after installation of the extensive green roof.

• 한국환경복원기술학회지
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• 제7권4호
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• pp.1-7
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• 2004

The purpose of the study is to review current status of green roof technology and to suggest the issues and solutions related with the technological problems of green roof in Korea. The scope of the study is limited to the extensive green roof which requires low maintenance. Technological issues related with green roof include soil, water proofing, water drain, vegetation and maintenance. Several solutions to invigorate green roof technology were suggested as follows; 1)implementation of technical standard for green roof and technology certification system, 2) development of suitable raw materials for green roof, 3) construction guidelines and uniform construction specification, 4) formulation of city ordinance for green roof, and 5) exchange program with foreign green roof organizations.

• KIEAE Journal
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• 제13권5호
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• pp.89-96
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• 2013

Green roofs can reduce surface water runoff, provide a habitat for wildlife moderate the urban heat island effect, improve building insulation and energy efficiency, improve the air quality, create aesthetic and amenity value, and preserve the roof's waterproofing. Green roofs are mainly divided into three types : intensive, simple-intensive, and extensive. Especially, extensive roof environment is a harsh one for plant growth; limited water availability, wide temperature fluctuations, high exposure to wind and solar radiation create highly stressed environment. This study, aimed at extensive green roof, was carried out on the rooftop of the library at Seoul Women's Univ. from October to November, 2012 and from March to August, 2013. To suggest the most effective vegetation model for biodiversity and heat island mitigation, surface temperatures were monitored by each vegetation model. We found that herbaceous plants of Aster sphathulifolius, Aceriphyllum rossii and Belamcanda chinensis, shrub of Syringa patula 'Miss Kim', Thymus quinquecostatus var. japonica, Sedum species can mixing each other. Among them, the vegetation models including Sedum takesimense, Aster sphathulifolius, Thymus quinquecostatus var. japonica was more effective on the surface temperature mitigation, because the species have the tolerance and high ratio of covering, and also in water. Especially, in the treatment of bark mulching, they helped to increase the temperature of vegetation models. In the case of summer, temperature mitigation of vegetation models were no significant difference among vegetation types. Compared to surface temperature of June, July and August were apparent impact of temperature mitigation, it shows that temperature mitigation are strongly influenced by substrate water content.

• KIEAE Journal
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• 제13권5호
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• pp.67-77
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• 2013

Based on the increasing demand for a solution to reduce thermal load, extensive green roofs have great opportunity for application to existing roofs due to their light-weight and easy maintenance. The present study delivers data regarding thermal behavior and heat reduction potential in relation to vegetation coverage between green roof types. 1) In the hottest hour in a day, green roofs showed considerable potential to mitigate heat load in roof environments, which can be up to $10^{\circ}C$ difference. 2) Compared to conventional cement roofs, the extensive green roofs only have a slight potential to cool the air over green roofs. By statistical analysis of linear regression, green coverage has little to do with the reduction of air temperature; the cooling effect was proven only in nighttime. 3) Green roofs act as an insulating roof membrane, the inner substrate of green roofs remained cooler than cement roof surfaces in the daytime, but in the nighttime the green roofs generally were warmer than the cement roof surfaces. 4) The variable of vegetation coverage resulted in no significant difference in thermal behavior in the air, but had the greatest effect in keeping the substrate cool in the daytime. The high vegetation coverage also hindered the rapid cooling of the substrate in the nighttime, and therefore was warmer than other measured temperatures. In order to draw a clear conclusion to combat urban heat island effect with extensive green roofs, the experiment needs to be applied on a larger scale.

• 한국환경복원기술학회지
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• 제19권2호
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• pp.55-69
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• 2016

Significant efforts are being devoted in mitigating the urban heat island effect, and extensive green roofs are an option for mitigation. The purpose of this study was to compare the surface temperature, vegetation types, and plant species on an extensive green roof. Test beds were created in May 2015, and the surface temperature was monitored from June to August. The test beds comprised polyculture and monoculture. Polyculture was divided into three types, and monoculture comprised eight plant species. An extensive green roof is effective in reducing temperature by forming a shade and preventing sunlight from falling on the surface of buildings, which mitigates the urban heat island effect. Consequently, the surface temperature of the green roof and that of concrete during summer reduced from $17.8^{\circ}C$ to $7.3^{\circ}C$. The temperature reduction was greater on using polyculture than on using monoculture, but monocultures of Sedum takesimense, Hemerocallis dumortieri, Allium senescens, Aster yomena, Belamcanda chinensis, and Aster koraiensis also produced good results. The temperature reduction effects of Polygonatum odoratum var. pluriflorum f. variegatum, Phlox subulata, and Thymus quinquecostatus var. japonica were excellent compared with those of concrete but were less than those of other plant species. Careful attention is needed for the management of extensive green roofs. Studies on the plant species and types of extensive green roof should continue to mitigate the urban heat island effect.

• Earthquakes and Structures
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• 제11권2호
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• pp.265-280
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• 2016

Environmental and operational benefits of green roofs are manifolds; however, their main disadvantages are cost and weight. New technology enabled the use of plastics to reduce the weight of green roof systems to promote their installation. To maximize their potential benefits, green roofs can be installed on existing structures. This study evaluates the influence of green roofs on the seismic response of 3, 6, and 8 storey reinforced concrete ductile moment resisting frames, which were designed according to current seismic standards, however, not designed for green roofs. For each frame, three different types of roofs are considered: gravel flat roof, extensive green roof, and intensive green roof. Nonlinear dynamic time history analysis using an ensemble of twenty real earthquake records was performed to determine the inter-storey drift demand and roof drift demand for each frame. Eigenvalue analysis was also performed to determine the impact of green roofs weight on the elastic and cracked periods of the structure. Results from the analysis demonstrated that intensive and extensive green roofs do not affect the seismic performance of reinforced concrete frame structures.

• 한국환경복원기술학회지
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• 제13권4호
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• pp.10-17
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• 2010

The objectives of this study were to compare the growth of Vitex rotundifolia as affected by the difference of soil depth and mixture ratio in a shallow-extensive green roof module system, and to identify the level of soil thickness and mixture ratio as suitable growing condition to achieve the desired plant growth in green roof. Different soil thickness levels were achieved under 7cm, 15cm and 25cm of shallow-extensive green roof module systems made by woody frame of $500{\times}500{\times}300mm$. Soil mixture ratio were eight types for perlite : peatmoss : leafmold = 7 : 1 : 2 (v/v/v, $P_7P_1L_2$), perlite : peatmoss : leafmold = 6 : 2 : 2 (v/v/v, $P_6P_2L_2$), perlite : peatmoss : leafmold = 5 : 3 : 2 (v/v/v, $P_5P_3L_2$), perlite : peatmoss : leafmold = 4 : 4 : 2 (v/v/v, $P_4P_4L_2$), only sand ($S_{10}$), sand : leafmold = 7 : 3 (v/v, $S_7L_3$), sand : leafmold = 5 : 5 (v/v, $S_5L_5$) and only leafmold ($L_{10}$). The growth response of Vitex rotundifolia had fine and sustain condition in $P_6P_2L_2$, $P_5P_3L_2$ and $P_4P_4L_2$., Especially, in case of $P_6P_2L_2$, growth response appeared to be good even in soil thickness 7cm, which showed low survival rates of Vitex rotundifolia in other soil mixtures. Tree height, root diameter, photosynthesis and chlorophyll contents tended to increase with increased soil thickness.

• 한국환경과학회지
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• 제19권7호
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• pp.871-877
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• 2010

The objectives of this study were to compare growth of Pllioblastus pygmaed and soil characteristics as affected by difference of soil thickness and mixture ratio in shallow-extensive green roof module system, and to identify the level of soil thickness and mixture as suitable growing condition to achieve the desired plants in green roof. Different soil thickness levels were achieved under 15cm and 25cm of shallow-extensive green roof module system that was made by woody materials for $500{\times}500{\times}300mm$. Soil mixture ratio were three types for perlit: peatmoss: leafmold=6:2:2(v/v/v, $P_6P_2L_2$), perlit: peatmoss: leafmold=5:3:2(v/v/v, $P_5P_3L_2$) and perlit: peatmoss: leafmold=4:4:2(v/v/v, $P_4P_4L_2$). On June 2006, Pllioblastus pygmaed were planted directly in a green roof module system in rows. All treatment were arranged in a randomized complete block design with three replication. The results are summarized below. In term of soil characteristics, Soil acidity and electric conductivity was measured in pH 6.0~6.6 and 0.12dS/m~0.19dS/m, respectively. Organic matter and exchangeable cations desorption fell in the order: $P_4P_4L_2$ > $P_5P_3L_2$ > $P_6P_2L_2$. $P_6P_2L_2$ had higher levels of the total solid phase and liquid phase, and $P_4P_4L_2$ had gas phase for three phases of soil in the 15cm and 25cm soil thickness. Although Pllioblastus pygmaed was possibled soil thickness 15cm, there was a trend towards increased soil thickness with increased leaf length, number of leaves and chlorophyll contents in 25cm. The growth response of Pllioblastus pygmaed had fine and sustain condition in order to $P_6P_2L_2$ = $P_5P_3L_2$ > $P_4P_4L_2$. However, The results of this study suggested that plants grown under $P_4P_4L_2$ appear a higher density ground covering than plants grown under $P_6P_2L_2$. Collectively, our data emphasize that soil thickness for growth of Pllioblastus pygmaed were greater than soil mixture ratio in shallow-extensive green roof module system.

• KIEAE Journal
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• 제13권3호
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• pp.105-110
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• 2013

Green roof system is classified as intensive greening, extensive greening or mix of intensive-extensive greening. Recently, light-weigh green roof has been performed actively, because buildings have been considered loads, design and maintenance. This study was conducted to design soil depth for light-vegetation block with using bottom-ash. As a result, it was found that growth of plant had no direct effect on soil depth even it was less than 10cm. Soil depth having under 5cm could be integration of plant roots and vegetation blocks. It was also possible to grow organic vegetables through the experiment of planting. According to this experiment, as light-vegetation block with bottom-ash was used for planting, it makes design shallow soil depth. The results will help install green roof system conveniently not only new buildings but also used buildings.

• 원예과학기술지
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• 제31권4호
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• pp.503-511
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• 2013

본 연구는 돌나물과 한국잔디를 식재한 경량 모듈형 옥상녹화시스템의 온도저감과 열수지를 평가하였다. 식물생육은 초고와 피복율을 측정하였으며, 2012년 8월 2일부터 3일까지 48시간 동안 콘크리트와 옥상녹화 표면, 토양 속, 모듈 하부의 온도와 순복사, 증발산량을 측정하였다. 기온이 $34.6^{\circ}C$로 가장 높았던 8월 3일 15:00시의 표면온도는 콘크리트가 $57.5^{\circ}C$로 가장 높았으며, 그 다음으로 돌나물 $40.1^{\circ}C$, 한국잔디 $38.3^{\circ}C$의 순으로 옥상녹화 조성 시 큰 폭으로 온도가 저감되는 것으로 나타났다. 토양 속과 모듈 하부도 옥상녹화에 의한 온도저감 효과가 나타났으며, 한국잔디가 돌나물보다 온도저감 효과가 큰 것으로 나타났다. 콘크리트 표면과 비교하여 옥상녹화 최고 온도는 약 2시간 정도 지연되는 것으로 나타났다. 표면의 온도저감에는 식물종, 기온, 토양수분이 영향을 미치고, 모듈 하부의 온도저감에는 식물종, 기온, 토양수분, 표면온도가 유의하게 영향을 미친 것으로 나타났다. 열수지 분석결과, 현열은 콘크리트 표면이 가장 높았으며, 옥상녹화 시 감소하는 경향을 보였으며 잠열은 한국잔디가 돌나물보다 높았다. 따라서 온열환경 개선을 위해서는 한국잔디가 돌나물보다 옥상녹화 적용에 더 효과적임을 알 수 있었다.