• Journal of Korean Association for Spatial Structures
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• v.10 no.1
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• pp.85-93
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• 2010

This paper suggests a vibration control method long span structures with trussed roof. Basic concept of this method is based on the energy absorption through hysteresis loop of an elasto-plastic element. This element is attached on the top of the column supporting the roof. Two different types of roofs and three of earthquake waves are used in the investigation. It shows that this is very efficient method to reduce the seismic energy of roof member transferred from the column.

• Geomechanics and Engineering
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• v.29 no.3
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• pp.229-236
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• 2022

In this study, a model experiment and field experiment was conducted to introduce the optimal tensile force when constructing a non-open cut tunnel according to the ground conditions of sandy soil. CMR (Concrete Modular Roof) method is economical because of the high precision and excellent durability, and corrosion resistance, and the inserted parts can be used as the main structure of a tunnel. In addition the CMR method has a stable advantage in interconnection because the concrete beam is press-fitted compared to the NTR (New Tubular Roof) method, and the need for quality control can be minimized. The ground conditions were corrected by adjusting the relative density of sandy soil during the construction of non-open cut tunnels, and after introducing various tensile forces, the surface settlement according to excavation was measured, and the optimal tensile force was derived. As a result of the experiment, the amount of settlement according to the relative density was found to be minor. Furthermore, analysis of each tensile force based on loose ground conditions resulted in an average decrease of approximately 22% in maximum settlement when the force was increased by 0.8 kN per segment. Considering these results, it is indicated that more than 2.0 kN tensile force per segment is recommended for settlement of the upper ground.

• Clean Technology
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• v.18 no.3
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• pp.295-300
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• 2012

Synthesis of well-defined particle with tunable size, shape, and functionalities is strongly emphasized for various applications such as chemistry, biology, material science, chemical engineering, medicine, and biotechnology. This study presents micromolding method for the fabrication of anisotropic particles with elegant control of curvature of covex roof. For the demostration of rapid fabrication of the particles, we have applied polydimethylsiloxane (PDMS) micromold as structure guiding template and wetting fluid to control curvature of roof of the particles. Based on this approach, we can control the radius of curvature from $20{\mu}m$ to $70{\mu}m$ with different aspect ratio of mold. In addition, wetting fluids with different wetting properties can also modulate the height and radius of curvature of the particles. We envision that this methodology is promising tool for precise control of particle shape in 3-dimensional space and new synthetic route for anisotropic particles with cost effective, simple, easy, and fast procedure.

• Journal of Bio-Environment Control
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• v.24 no.3
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• pp.252-257
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• 2015

Fruit cracking and vine leaf spot of grapes tend to occur when the plants were directly exposed to rain under outdoor culture. Rain shelter facility can be an alternative method to prevent the cracking and disease of grape, but it also has some limitations in practical usages. We designed rain shelter facility which can completely shut out the rain and ventilate naturally, and it was upgraded to meet the standards of disaster prevention against snow and wind load. The newly developed rain shelter has two-story roof structure, and the $2^{nd}$ floor roof was equipped over $1^{st}$ floor roof at a distance of 40cm. For natural ventilation and water proof, the upper roof protruded about 50cm from the ridge of a $1^{st}$ floor roof. The various tests were carried to examine such as grape quality, brown spot and fruit cracking of Campbell Early under the conventional and the newly developed rain shelter facility which was built about $100{\ss}{\check{S}}$. In comparison of temperature between the conventional and the newly developed rain shelter facility when outside temperature was more than $34^{\circ}C$, the inside temperature was recorded as $40.7^{\circ}C$ and $37.4^{\circ}C$, respectively. There was no significant difference between the two facilities when outside was below $32^{\circ}C$ The quality such as soluble solids and marketable fruit was increased, and fruit cracking of grapes and vine leaf spot also drastically diminished in the newly developed rain shelter.

• Korean Journal of Remote Sensing
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• v.38 no.6_2
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• pp.1607-1622
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• 2022

The purpose of this study is to determine the actual performance of cool roof in preventing absorbed solar radiation. The spatial correlation between surface temperature and absorbed solar radiation is the method by which the performance of a cool roof can be understood and evaluated. The research area of this study is the vicinity of Jangyu Mugye-dong, Gimhae-si, Gyeongsangnam-do, where an actual cool roof is applied. FLIR Vue Pro R thermal infrared sensor, Micasense Red-Edge multi-spectral sensor and DJI H20T visible spectral sensor was used for aerial photography, with attached to the drone DJI Matrice 300 RTK. To perform the spatial correlation analysis, thermal infrared orthomosaics, absorbed solar radiation distribution maps were constructed, and land cover features of roof were extracted based on the drone aerial photographs. The temporal scope of this research ranged over 9 points of time at intervals of about 1 hour and 30 minutes from 7:15 to 19:15 on July 27, 2021. The correlation coefficient values of 0.550 for the normal roof and 0.387 for the cool roof were obtained on a daily average basis. However, at 11:30 and 13:00, when the Solar altitude was high on the date of analysis, the difference in correlation coefficient values between the normal roof and the cool roof was 0.022, 0.024, showing similar correlations. In other time series, the values of the correlation coefficient of the normal roof are about 0.1 higher than that of the cool roof. This study assessed and evaluated the potential of an actual cool roof to prevent solar radiation heating a rooftop through correlation comparison with a normal roof, which serves as a control group, by using high-resolution drone images. The results of this research can be used as reference data when local governments or communities seek to adopt strategies to eliminate the phenomenon of urban heat islands.

• Journal of Forest and Environmental Science
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• v.34 no.3
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• pp.258-261
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• 2018

Drought alters soil microorganisms; however, it is still not clear how soil microbes respond to severe drought conditions. In this study, the responses of soil bacterial community to experimental drought in a coniferous stand were examined. Six $6m{\times}6m$ plots with three replicates of control and drought treatments were delimited. PCR amplification and Illumina sequencing were conducted for cluster analysis of soil bacterial community and species richness and species diversity was analyzed. Along the 393 days of simulated drought from July 2016 to October 2017, soil bacterial species diversity slightly increased whereas species richness decreased in both control and roof plots. Moreover, soil bacterial species richness more decreased in roof plots than in controls. Combining these results, soil bacterial activity might have been altered by simulated drought.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.4
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• pp.27-40
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• 2013

These day morden cities have serious climatic problems due to enviornmental load caused by excessive development of urbanization. As technological improvement to answer to various ecological disasters and climate changes are also called on the field of construction, inter-disciplinary studies linked to the estabilishment of sustainable energy generation systems and enviornmental control is needed in a consilient point of view. This study aims to analyse optimal site conditions for photovoltaic system and green roof planting through solar radiation simulation in a integrated perspective. In so doing, it seeks to proffer basic study for developing a sound use of roof area that is sustainable in environmental and resources aspects. A computer simulation showed that, in the case of total seasonal solar radiation, summer season resulted 312.5kWh in 35% of total annual solar radiation. This season indicated the lowest radiation rate of the year for direct sunlight in 45.8% of total seasonal solar radiation. Due to such solar radiation simulation, at the largest optimal planting area, Glechoma hederacea var. longituba secured $719.16m^2$ of gross roof area.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.227-228
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• 2012

In contemporary architectural practice, flat sections and plan drawings are no longer a primary means of representation and communication with participants. A typical building design has an ornamental exterior wall system and a roof system that should have water-proof quality and drainage function. By comparison, distinction between exterior wall and roof are unclear in freeform buildings, and they are integrated into a concept of a building envelope. This study is to propose 3D coordinate control technology for freeform structure by CNC curved tube method in order to develop a BIM-based envelope design and construction method for freeform building. Because a much wider freeform building construction can be achieved with correct 3D data and easy-to-implement in construction field, the proposed 3D coordinate control technology is highly recommended for practical use instead of the conventional CAD system.

• 한국지형공간정보학회:학술대회논문집
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• 2002.11a
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• pp.133-140
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• 2002

This paper presents a method for line segment grouping used for detection of various building roofs. First, by using edge preserving filtering. noise is eliminated and then images are segmented by watershed algorithm, which preserves location of edge pixels. To extract line segments between control points from boundary of each region, we calculate curvature of each pixel on the boundary and then find the control points. Line linking is performed according to direction and length of line segments and finally the location of line segments is adjusted using gradient magnitudes of all pixels of the line segment. The algorithm has been applied to aerial imagery and the results show accurate building roof detection.

• Geomechanics and Engineering
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• v.18 no.4
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• pp.439-448
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• 2019

The bearing capacity of roadside support is the key problem in gob-side entry retaining technology. To study the cooperative bearing characteristics of the roof-roadside support-floor along the gob-side entry retaining, a mechanical model of the composite structure of the roof-roadside support-floor was first established. A method for determining the structural parameters of gob-side entry retaining was then proposed. Based on this model, adaptability analysis of roadside support was carried out. The results showed that the reasonable width of the gob-side entry roadway was inversely proportional to the mining height, and directly proportional to the bearing strength of the roof and floor. And the reasonable width of the "flexible-hard" roadside support was directly proportional to its own strength, and inversely proportional to the width of the gob-side entry retaining. When determining the position and size of the roadside support along the gob-side entry retaining, the surrounding rock environment should be fully considered. Measured results from case study also show the rationality of the model and calculation method.