• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.25-26
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• 2023

The internal core material and external color of a sandwich panel have a significant impact on the performance of the sandwich panel. For use on roofs and walls, the internal core material and external color must be considered. Therefore, the surface and back side temperatures were measured for each exterior color and inner core material type. For the internal core materials, urethane foam and Expanded Poly Styrene(EPS), which are core materials mainly used in sandwich panels, were selected. As colors, black and ivory were selected according to brightness, and a total of five colors were selected: red, blue, and green, which are the three primary colors of light. As a result, there were differences in surface and temperature depending on the external color and type of internal core material. Regardless of the color, the temperature was measured lower for panels with urethane foam than for panels with an internal core of EPS. This is believed to have been influenced by the difference in thermal conductivity of urethane foam being 0.023W/(m·K) and that of EPS being 0.032W/(m·K). In addition, panels with a black exterior color were found to have higher surface and back temperatures than panels of other colors, and ivory-colored panels had lower back temperatures regardless of the core material. This is proportional to the brightness and light-absorbing characteristics.

• Korean Journal of Environment and Ecology
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• v.28 no.3
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• pp.357-364
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• 2014

This study aimed to determine effects of the use of water-retention additive, hydrophilic polymer, for extensive green roofs on growth of Juniperus chinensis var. sargentii and Euonymus fortunei 'Emerald and Gold' for woody plants, and Carex kobomugi and Carex pumila for herbaceous plants. Five different contents of hydrophilic polymer including 0% (Control), 1.0%, 2.5%, 5.0%, and 10% (polymer: medium (w/w), dry weight basis) were added to each of the container filed with a 100 kg of growth medium. Ten of plants were transplanted in each of square container ($1m(L){\times}1m(W){\times}0.3m$ (H)) built on the roof platforms in randomized complete block design in the $20^{th}$ of May, 2013. In results, excessively high volumetric soil water content, about 97-98%, was found in the substrate under elevated hydrophilic polymer concentration of at least 2.5%, during the entire growing period. The moisture content of the substrate containing 1.0% of hydrophilic polymer was higher about 20% in the range between 70% and 80%, compared tho that of Control substrate in the range between 50% and 60%, for 27 days after transplanting prior to abundant rainfall, indicating that the application of hydrophilic polymer to the extensive green roof substrate is effective to eliminate drought condition by retaining water in the substrate. Euonymus fortunei 'Emerald and Gold' and Carex kobomugi resulting in higher plant growth with 2.5% than those of the other treatment plants. Juniperus chinensis var. sargentii was observed the highest growth under 1.0% hydrophilic polymer treatement, and Carex pumila was founded the best growth with Control respectively. Plants that grown in both the 1.0% and 2.5% hydrophilic polymer survived all, while the plants that grown in the 5.0% and 10% hydrophilic polymer died after 3 months. These results suggest that advantage of the addition of hydrophilic polymer may be greater in drought-tolerant plants, but the mixture proportion of hydrophilic polymer should be determined according to the different features of the plant species being grown.

• Korean Journal of Agricultural Science
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• v.38 no.4
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• pp.641-649
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• 2011

This study was to analyze the soil environmental characteristics and vegetation status of green roof in Daejeon Metropolitan City. The investigated floras of vascular plants are 17 families, 26 genera, 28 species in Seo-Gu Daejeon District Office Building (SG), 25 families, 49 genera, 56 species in Galma Public Library (GP), and 34 families, 57 genera, 60 species in Daejeon City Hall (DC) respectively. Although the larger area shows the more numbers of species in introduced plants and naturalized plant, the naturalized plant ratios were similar with each other. They were 10.71%, 10.71%, and 11.67% at SG, GP, and DC respectively. As a result of analysis on soil physical property, soil depths including vegetation soil and drainage soil of 3 green roofs were 30cm. The depths of vegetation soil at SG, GP, and DC were 0~8cm, 0~10cm, 0~10cm respectively. As a results of soil chemical properties of our study, soil pH of vegetation soil and drainage soil were a range of 6.42 and 7.43, and a range of 6.55 and 7.43 on the average respectively. Available-P contents of vegetation soil and drainage soil were a range of 153.33 and 366.33mg/kg, and a range of 136.67 and 242.67 mg/kg which is very high, respectively. Carbon contents in soil at vegetation soil and drainage soil were a range of 3.16 and 6.38%, and a range of 1.63 and 2.47% respectively. Carbon storage per square meter within 30 cm were 2.76 kg, 2.99 kg, and 3.66 kg at SG, GP, and DC respectively.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.1
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• pp.27-37
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• 2013

A roof surface temperature monitoring, utilizing remotely sensed thermal infrared image has been specifically proposed to explore evidential data for heating load in winter by cool roof. The remotely sensed thermal infrared image made it possible to identify area-wide patterns of changing trends of surface temperature according to rooftop color (white, black, blue, green) which cannot be acquired by traditional field sampling. The temperature difference of cool roof having a higher solar reflectance were ranged from $3^{\circ}C$ up to $9^{\circ}C$, compared to the general roofs. It is confirmed that there is a significant potential to the energy saving by introducing the cool roof in a Korean climate since up to $18.46^{\circ}C$ difference in cool roof, compared to the general roofs in summer were already identified in Seoul, South Korea. It is anticipated that this research output could be used as a valuable reference in identifying heating load in winter by cool roof since an objective monitoring has been proposed based on the area-wide measured, fully quantitative performance of remotely sensed thermal infrared image.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.5 s.112
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• pp.69-82
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• 2005

These studies were carried out (1) to investigate the growth characteristics of Sedum album L. in the field, (2) to propose a suitable shallow peen roof system for this plant, and (3) to evaluate plant growth in the proposed system over the long term. The growth characteristics, such as morphological properties, growth habit, shade tolerance, and flowering, were surveyed. In experimental shallow green-roof systems, the effects of drainage type, substrate type, and soil depth on plant growth were investigated. Then drought tolerance was investigated. After planting Sedum album L. in the proposed system survival rate, cover, and resistance to insects, heal and cold were evaluated for about 2 years. The results of these studies are summarized below. 1. In the field, the aboveground part of Sedum album L. did not die back during the winter. Plant height was 4$\sim$7 cm. Roots were distributed to a depth of 5$\sim$7 cm. Sedum album L. is a compact ground-cover plant that spreads vigorously. Shading condition of less than $30\%$ of full sunlight didn't cause any trouble, but shading conditions above $87\%$ made the shape of the shoots and leaves abnormal. The plant bloomed from June to August and had a rather large compound umbel of white, star-shaped flowers. 2. Two systems, a drainage-blend-10 cm soil depth and a reservoir$\cdot$drainage-blend-15 cm soil depth, performed best in terms of cover, fresh weight, and dry weight. The first has an advantage for green roofs because it is lighter than the latter. 3. In drainage-blend-10 m soil depth and modified reservoir · drainage-blend-10 cm soil depth system no plants died for about 4 months after stopping the irrigation. The visual quality of the latter system was above 5 for 4 months and that of the former was under 5 after 2 months. In the field, however, the drought tolerance of Sedum album L. grown in the former would be enough to withstand the dry season. Considering the urban ecosystem and the importance of healthy growth the modified reservoir $\cdot$ drainage-blend-10 cm soil depth system was finally recommended. This system was composed of a 4 cm thick drainage layer and drain outlets placed at a height of 2.5 cm. 4. In the proposed system, the survival rate was $100\%$, and there was no injury induced by insects and heat. The leaf density decreased a little in winter. Cover increased throughout the year. Sedum album L. was planted with a cover of 72$cm^{2}$ on 3 April 2003; on 16 June 2003 and 15 June 2004, cover was $132.66\pm$5.87 $cm^{2}$(1.8 times) and $886.98\pm$63.51 $cm^{2}$(12.3 times), respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3983-3989
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• 2014

As the storm water runoff characteristics in urban areas have changed owing to urbanization, centralized facilities to reduce the urban flood runoff had been implemented. On the other hand, because they have their limitations, LID (Low Impact Development) of the distributed facilities for storm water runoff reduction is being actively planned and applied. The purpose of this study was to analyze the runoff characteristics for the spatial distribution of typical LID element techniques. This study set a study basin consisting of the five subbasins with the same basin and drainage systems, and analyzed the flood runoff characteristics from the two scenarios, one is for the locations and the other is for the number of green roofs (GR) and permeable pavement (PP), respectively, selected as typical LID element techniques. The SWMM implementation results showed that GR reduces 11.07% of the total and 3.42% of the peak amounts of storm water runoff, and PP leads to 18.09% of the total and 17.94% of the peak discharge reduction for a subbasin. Such a reduction rate is constant regardless of the LID locations, and increases linearly with the number of LID applications. The different runoff reduction rates between the GR and PP applications appear to be due to the effects of the different hydraulic conductivities in the control parameters for each LID.

• Journal of Environmental Impact Assessment
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• v.24 no.1
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• pp.16-34
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• 2015

Impervious covers(IC) are artificial structures, such as driveways, sidewalks, building's roofs, and parking lots, through which water cannot infiltrate into the soil. IC is an environmental concern because the pavement materials seal the soil surface, decreasing rainwater infiltration and natural groundwater recharge, and consequently disturb the hydrological cycle in a watershed. Increase of IC in a watershed can cause more frequent flooding, higher flood peaks, groundwater drawdown, dry river, and decline of water quality and ecosystem health. There has been an increased public interest in the institutional adoption of LID(Low Impact Development) and GI(Green Infrastructure) techniques to address the adverse impact of IC. The objectives of this study were to construct the modeling site for a samll urban watershed with the Storm Water Management Model(SWMM), and to evaluate the effect of various LID techniques on the control of rainfall runoff processes and non-point pollutant load. The model was calibrated and validated using the field data collected during two flood events on July 17 and August 11, 2009, respectively, and applied to a complex area, where is consist of apartments, school, roads, park, etc. The LID techniques applied to the impervious area were decentralized rainwater management measures such as pervious cover and green roof. The results showed that the increase of perviousness land cover through LID applications decreases the runoff volume and pollutants loading during flood events. In particular, applications of pervious pavement for parking lots and sidewalk, green roof, and their combinations reduced the total volume of runoff by 15~61 % and non-point pollutant loads by TSS 22~72 %, BOD 23~71 %, COD 22~71 %, TN 15~79 %, TP 9~64 % in the study site.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.590-599
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• 2014

This study was conducted to compare the cold tolerance of seven ground cover species, Orostachys japonica, Sedum oryzifolium, S. kamtschaticum 'SG1', S. reflexum, S. rupestre 'Blue Spruce', S. spurium 'Green Mental', and S. takesimense, which have been used for green roof and wall systems in Korea. Plants were grown in 10-cm pots and 1 g of tissues at stem-end and crown of each species were kept under either light or dark condition, respectively. For cold tolerance tests, plants were initially left at $4^{\circ}C$ and linearly cooled to 0, -4, -8, -12, -16, and $-20^{\circ}C$ at $-2^{\circ}C{\cdot}h^{-1}$ rate. Low temperature injury and regrowth rates were visually evaluated and assessed by image analysis, respectively. The lethal temperature ($LT_{50}$) of plant species was determined using electrolyte leakage measurements. S. reflexum was the most cold tolerant, showing the most survival at $-16^{\circ}C$, whereas S. oryzifolium and S. takesimense showed low temperature injury at $-8^{\circ}C$. Similar results were found with electrolyte leakage measurements at the stem end. For each species, the crown (Mean $LT_{50}:\;-12.15^{\circ}C$) was more cold tolerant than the stem end (Mean $LT_{50}:\;-10.47^{\circ}C$). In conclusion, S. reflexum and S. rupestre 'Blue Spruce' are recommended for planting in the central region of Korea during late fall and early winter, as they were more cold tolerant and showed more vigorous regrowth than the other tested plant species.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.3
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• pp.98-106
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• 2010

This study focuses on the appropriate planting soil for Vitex rotundifolia by planting soil. Different soil depth levels were achieved at 15cm and 25cm in the green roof module system that was created with woody materials for a $500{\times}500{\times}300mm$ area. The soil mixture ratio was $S_{10}$, $L_{10}$, $S_7L_3$, $S_5L_5$, $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$ and $P_4P_4L_2$. This study was carried out over five months between April and September, 2006. The amount of soil moisture tends to decrease according to the planting soil. For the experimental items $S_{10}$, $S_7L_3$ and $S_5L_5$, the amount of soil moisture tends to decrease rapidly. However, for the experimental items $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$ and $P_4P_4L_2$, conditions containing perlite and peat moss, the amount of moisture tends to decrease more gradually. As a result, the use of soil-improving amending for the afforestation planting of roofs with a low level of management is need. After experimenting with the ratio of soil mixture for Vitex rotundifolia, the planting soil for experimental item $P_6P_2L_2$, $P_5P_3L_2$ and $P_4P_4L_2$ appeared excellent. For experimental item $S_{10}$, the growth of Vitex rotundifolia seemed to be weaker than that of others, because of the low levels of moisture and organic matter in the soil. For experimental item $L_{10}$, there appeared to be a low level of growth, even when the levels of moisture and organic matter were high. This may have occurred because of the low level of soil pH and the excessive amount of exchangeable cation. At the depth of 25cm, the growth of Vitex rotundifolia is vigorous overall. For experimental item at 15cm, Vitex rotundifolia was able to survive for 14 days without any rainfall and Vitex rotundifolia was better in amended soil, $P_6P_2L_2$, $P_5P_3L_2$ and $P_4P_4L_2$, than natural soil, SL.

• Korean Journal of Heritage: History & Science
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• v.47 no.2
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• pp.86-113
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• 2014

This study has researched the characteristics and elements of Chwibyeong (翠屛), a sort of trellis in the Joseon Dynasty through the old documents, and the original form of Chwibyeong at Juhapru (宙合樓) in Changdeuk Palace. The results were as follow. First, as the result of literatures analysis for Imwon-gyeongje-ji (林園經濟志) and Jeungbo-sallim-gyeongje (增補山林經濟), the plant screen was classified as kinds of support[frame] material, plants and methods of planting. It was found that the supports of Chwibyeong were made of bamboo or the material such as the Jinjangmok (眞長木: a stick of oak) and Giryu (杞柳: Salix purpurea var. japonica). The evergreen coniferous trees including Pinus densiflora, Taxus cuspidata and Thuja orientalis were mainly used for the plant material of Chwibyeong. The general planting method of Chwibyeong was to plant on the ground, but sometimes the container planting was also found on the artificial ground. Second, the term of 'Chwibyeong' in the literatures was used in only the screen made by evergreen trees, and the superordinate category term of it was indicated by 'byeong (屛)'. Therefore Chwibyeong was a compound word formed from 'chwi (翠)' which means the characteristics of evergreen and 'byeong' as tree screen which the support was made by bamboo. And Chwibyeong had semantic context which was combined with the literary symbolization to describe a landscape of green peak and Taoist ideology be inherent from 'twelve peaks of Musan[巫山十二峰]' in Sichuan sheng (四川省). Thirdly, the photograph of Chwibyeong at Juhapru taken by the 1880s, showed that Chwibyeong was made with coniferous trees and was almost 2 meters high. The Chwibyeong at Juhapru was removed during the Japanese colonial era, but a few yew trees(Taxus cuspidata) used for Chwibyeong are still remaining. And some Juniperus chinensis which the composition time is unclear, were cultivated while hung loose its branchs at the sides of Eosumun (魚水門). This Junipers were presumed to be planted by Japanese after Japanese annexation of Korea(1910), and it was judged that both of the roofs of Eosumun's side gates might have been transformed into Japanese style at the same time. Lastly, Chwibyeong at Juhapru was restored in 2008 but it was restored in wrong way from original form without precise research. Especially Chwibyeong was restored with Sasa boreralis which is damaged by frost, so it requires exertion that should revive the originals to plant original material as much as possible. And it needs the development of fabrication technique for Chwibyeong and the application to current landscape architecture.