• Wind and Structures
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• v.8 no.4
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• pp.283-294
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• 2005

This paper describes the work of the Working Group on wind pressure coefficients on low-rise structures, one of the groups set up by the International Association of Wind Engineering in 1999. General aspects of wind loading on low-rise structures are summarized. The definition, derivation and codification of loading coefficients is described. Comparisons of pressure coefficients on low rise structures are made between a selection of wind loading standards. Recommendations for consistency and for the harmonization of these coefficients are given.

• Journal of Korean Association for Spatial Structures
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• v.1 no.1 s.1
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• pp.34-42
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• 2001

The development of contemporary spatial structures for long-span roofs in China was initiated in the 19505. Space trusses, reticulated shells and cable suspended structures have been developing rapidly since 1980s. Recently there has been a growing interest in tensile membrane structures. Comprehensive theoretical study has been carried out parallel to the engineering application, which provided necessary theoretical support to the development of different types of spatial structures.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.67-68
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• 2010

Segmentation of LiDAR data is an important procedure in building modeling. Therefore, in this study, aerial imagery is used to group LiDAR data for both improving segmentation accuracy and modeling detail surface patches of the roofs. The results show that the proposed method is efficient to analyze and to model various types of roof shape.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.225-226
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• 2010

The problem in orthoimage generation is to recover occlusion areas. In this study, occlusion areas - double mapping regions of the building roofs - were mutually corrected by using multiple images. The proposed method could be efficient for generating true orthoimages in urban areas.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.235-238
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• 2010

Since the mid 1990s airborne LiDAR data have been widely used, automation of building modeling is getting a central issue. LiDAR data processing for building modeling is involved with extracting surface patch elements by segmentation and surface fitting with optimal mathematical functions. In this study, simulation LiDAR data were generated with complex polyhedral roofs of buildings and an automatic modeling approach was proposed.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.895-897
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• 2005

이차원 평면에 직교다각형이 주어져 있을 때, 직교다각형 위에 45도 각도로 기울어진 면들로 구성된 지형 구조인 지붕(roof)을 정의할 수 있다. 본 논문에서는 직교다각형에 대한 지붕의 다양한 기하학적 성질을 살펴본다. 이것은 인공위성으로부터 얻은 건물의 평면도 이미지로부터 3차원 지붕구조를 획득하여 출력함으로써 사실감있는 영상을 제공하는 데 활용될 수 있다.

• Wind and Structures
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• v.14 no.5
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• pp.383-411
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• 2011

Roof is an integral part of building envelope. It protects occupants from environmental forces such as wind, rain, snow and others. Among those environmental forces, wind is a major factor that can cause structural roof damages. Roof due to wind actions can exhibit either flexible or rigid system responses. At present, a dynamic test procedure available is CSA A123.21-04 for the wind uplift resistance evaluation of flexible membrane-roofing systems and there is no dynamic test procedure available in North America for wind uplift resistance evaluation of rigid membrane-roofing system. In order to incorporate rigid membrane-roofing systems into the CSA A123.21-04 testing procedure, this paper presents the development of a load cycle. For this process, the present study compared the wind performance of rigid systems with the flexible systems. Analysis of the pressure time histories data using probability distribution function and power spectral density verified that these two roofs types exhibit different system responses under wind forces. Rain flow counting method was applied on the wind tunnel time histories data. Calculated wind load cycles were compared with the existing load cycle of CSA A123.21-04. With the input from the roof manufacturers and roofing associations, the developed load cycles had been generalized and extended to evaluate the ultimate wind uplift resistance capacity of rigid roofs. This new knowledge is integrated into the new edition of CSA A123.21-10 so that the standard can be used to evaluate wind uplift resistance capacity of membrane roofing systems.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.5
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• pp.110-120
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• 2009

The hipped roof on the research building, which was constructed 51.9m above sea level on a hillock by Korea National University of Education in June 1999, is composed of four inclined planes which are 12m in breadth, 8m in length and have a 30 degree gradient. For the roof vegetation, the yellow earth collected from around the building was laid on top. It was designed to supply the soil on the slope with water for a considerable period by making rainfall pool at the edges. In order to prevent the soil on the slope from being swept away, 31 sorts of grass seeds were imported from Germany and sown in the soil. At the present day, 10 years after the seeds began to sprout and inhabit the settled slope, 30 individual plant species were identified in the period between April 2008 and March 2009. Out of 31 species were seeded on the slanted, soiled roof, only 8 were still alive. It was confirmed that the Artemisia Princeps var, Chrysantheum, Prunella Vulgaris and Lespedeza Cuneata have been the major species inhabiting the east, west, south and north inclined planes respectively. The Phragmites Communis was inhabiting the edge of the roof where the water supply was adequate, while the Dianthus Barbatus was primarily inhabiting the south-east side of the roof. As a whole, 26 identifiable plants and 4 unidentified plants were observed on the inclined planes of the hipped roof. In consideration of the plant distribution on the slope, it was confirmed that the selection of seeds may have had an effect on the slope vegetation. As for the yellow earth laid on the roof, it was discovered that about 2~3cm thickness around the ridge was swept away, but the rest of the slope was in relatively good condition. Accordingly, it has been proven that vegetations can be applied to hipped roofs by using ordinary plants without any special structural measures.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.2
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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.

• KIEAE Journal
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• v.11 no.4
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• pp.29-36
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• 2011

The aim of this study was to study the functions and roles of Green Community Rediscovery Center (GCRC) in terms of community integration, to design GCRC with various types of green roofs, and to investigate the possibility of applying a renewable energy system (e.g., PV) to the building greenery systems. The four major functional modules for GCRC were suggested: implementation of ecopark and community gardens with environmental education programs, implementation of green housing model with education programs, Discover Science Center, and implementation of green business model with education programs. Three major functions of the center are also presented in terms of design: 1) functions of community gardens; 2) establishment of a green business model, community composting system and an urban farming system; and 3) roles of community gardens in social interactions within GCRC. GCRC provides residents with the opportunities of community gardens, urban farming based on a successful recycling system, as well as a green business model and environmental education programs near their homes. The air temperature of the green roof (utilizing Sedum sarmentosum as a cover plant) was approximately $3^{\circ}C$ lower than that of the non-green roof, indicating a potential efficiency increase in PV systems for GCRC. It was concluded that the GCRC suggested would enhance the neighborhood satisfaction, improve the quality of life and contribute to social integration and community regeneration.