• Journal of the Korean Institute of Rural Architecture
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• v.24 no.1
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• pp.1-8
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• 2022

Among Korea's national folk cultural heritage, eight villages have been designated, and 37 years have passed since Hahoe Village was first designated in 1984. All eight villages have been constantly inhabited by residents from the past to the present, so the cultural value of inferring the lives of our ancestors in the past is very high. However, due to the inconvenience of the settlement environment in existing houses due to changes in the living environment, buildings such as various residential facilities and warehouses have been installed and expanded without permission, losing the original cultural property landscape and building. In addition, complaints and conflicts from residents are accumulating due to the poor living environment in the village. Therefore, this study intends to present guidelines for conservation and maintenance that can embrace changes in resident's housing and living environment, based on the 'maintenance of original form', the grand principle of the Cultural Properties Protection Law about the Jeju Seongeup Village. In particular, the maintenance plan is largely subdivided into legalization, demolition, expansion and reconstruction, and detailed standards for each item and examples applied are proposed. Through this, it aims to become basic data on the starting point of realistic improvement measures for cultural properties and residents to coexist.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.53-54
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• 2021

Grenfell Tower was renovated in 2014 and 2016 at a high cost to replace the exterior materials, windows and co-heating facilities of the building. The exterior materials used during the repair work were sandwich panels filled with polyethylene and plastic, which were expanded on the aluminum metal surface. It is a product called Celotex RS 5000, a low-resolution but inexpensive repair material, and is currently an external material that cannot be used in high-rise buildings. Similar domestic fire cases began to focus social attention on the safety of high-rise buildings through the Busan Residential Complex Fire (2010), Uijeongbu Urban Living Housing Fire (2015), and Ulsan Residential Complex Fire (2020), and residents' safety concerns are increasing. In Korea, the occurrence and risk of similar fires are high, so setting up fire prevention measures through fire case investigation is considered the most basic measure in securing human safety. Therefore, the purpose of this study is to examine the status of fire damage caused by domestic and foreign eruptions, domestic and international research status and related regulations on external materials and windows starting from the Grenfell Tower fire in England.

• Design & Manufacturing
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• v.17 no.2
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• pp.62-69
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• 2023

In this study, we conducted a study on the optimization of injection molding conditions to minimize deformation of plastic product. The charging management system housing of the vehicle was selected as the research subject. Melting temperature, cooling temperature, packing time, and packing pressure were selected as the main factors expected to affect the deformation of molded products. Each main factor was divided into 5 levels. Optimization of injection molding conditions to minimize deformation was performed using the Taguchi Method. We performed an analysis of variance (ANOVA) to identify significant factors affecting the deformation of plastic product. In order to select injection molding conditions that minimize deformation of plastic products, injection molding analysis was additionally performed for insignificant factors. We then compared the deformation of the molded part before and after optimization. As a result of comparing the injection analysis results of the basic conditions and the injection analysis results of the optimal conditions, it was confirmed that the amount of deformation after optimization was improved by about 10.9%.

• Geomechanics and Engineering
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• v.31 no.3
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• pp.281-289
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• 2022

Bio-CaCO₃ is a blowout environment-friendly materials for soil improvement and sealing of rock fissures. To evaluate the chemical characteristics, shape, size and productivity of soybean urease induced CaCO₃ precipitates (SUICP), experimental studies were conducted via EDS, XRD, FT-IR, TGA, BET, and SEM. Also, the conversion rate of SUICP reaction at different time were determined and analyzed. The Bio-CaCO₃ product obtained by SUICP is comprehensively judged as calcite based on the results of EDS, XRD and FT-IR. The SUICP calcite precipitates are detected as spherical or ellipsoidal particles 3-6 ㎛ in diameter with nanoscale pores on their surface, and this morphology is novel. The median secondary particle size d₅₀ is 39-88 ㎛, indicating the agglomeration of the primary calcite particles. The Bio-calcite decomposes at 650-780℃, representing a medium thermal stability. The conversion rate of SUICP reaction can reach 80% in 24h, which is much more efficient than microbially induced CaCO₃ precipitation. These results reveal the knowledges of SUICP, and further direct its engineering applications. Moreover, we show an economic channel to obtain porous spherical calcite.

• Structural Monitoring and Maintenance
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• v.10 no.3
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• pp.243-260
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• 2023

Indonesia has had seismic codes for earthquake-resistant structures designs since 1970 and has been updated five times to the latest in 2019. In updating the Indonesian seismic codes, seismic hazard maps for design also update, and there are changes to the Peak Ground Acceleration (PGA). Indonesian seismic design uses the concept of building performance levels consisting of Immediate occupancy (IO), Life Safety (LS), and Collapse Prevention (CP). Related to this performance level, cases still found that buildings were damaged more than their performance targets after the earthquake. Based on the above issues, this study aims to analyze the performance of base isolation design on existing target buildings and analyze the seismic fragility for a case study in Indonesia. The target building is a prototype design 8-story medium-rise residential building using the reinforced concrete moment frame structure. Seismic fragility analysis uses Incremental Dynamic Analysis (IDA) with Nonlinear Time History Analysis (NLTHA) and eleven selected ground motions based on soil classification, magnitude, fault distance, and earthquake source mechanism. The comparison result of IDA shows a trend of significant performance improvement, with the same performance level target and risk category, the base isolation structure can be used at 1.46-3.20 times higher PGA than the fixed base structure. Then the fragility analysis results show that the fixed base structure has a safety margin of 30% and a base isolation structure of 62.5% from the PGA design. This result is useful for assessing existing buildings or considering a new building's performance.

• Advances in concrete construction
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• v.16 no.5
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• pp.269-276
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• 2023

In order to study the effect of rubber particle size and admixture on the frost resistance of self-compacting concrete, three self-compacting concrete specimens with equal volume replacement of fine aggregate by rubber particles of different particle sizes were prepared, while conventional self-compacting concrete was made as a comparison specimen. The degradation law of rubber aggregate self-compacted concrete under freeze-thaw cycles was investigated by fast-freezing method test. The results show that the rubber aggregate has some influence on the mechanical properties and freeze-thaw durability of the self-compacting concrete. With the increase of rubber aggregate, the compressive strength of self-compacting concrete gradually decreases, and the smaller the rubber aggregate particle size is, the smaller the effect on the compressive strength of the matrix; rubber aggregate can improve the frost resistance of self-compacting concrete, and the smaller the rubber particle size is, the more obvious the effect on the improvement of the frost resistance of the matrix under the same dosage. Through the research of this paper, it is recommended to use 60~80 purpose rubber aggregate and the substitution rate of 10% is chosen as the best effect.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2412-2420
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• 2024

The International Atomic Energy Agency (IAEA) mandates safeguards to ensure non-proliferation of nuclear materials. Among inspection techniques used to detect partial defects within spent nuclear fuel (SNF), gamma emission tomography (GET) has been reported to be reliable for detection of partial defects on a pin-by-pin level. Conventional GET, however, is limited by low detection efficiency due to the high density of nuclear fuel rods and self-absorption. This paper proposes a new type of GET named Spent Fuel Internal Tomography (SFIT), which can acquire sinograms at the guide tube. The proposed device consists of the housing, shielding, C-shaped collimator, reflector, and gadolinium aluminum gallium garnet (GAGG) scintillator. For accurate attenuation correction, the source-distinguishable range of the SFIT device was determined using MC simulation to the region away from the proposed device to the second layer. For enhanced inspection accuracy, a proposed specific source-discrimination algorithm was applied. With this, the SFIT device successfully distinguished all source locations. The comparison of images of the existing and proposed inspection methods showed that the proposed method, having successfully distinguished all sources, afforded a 150 % inspection accuracy improvement.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.2
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• pp.138-148
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• 2022

The 1920s and 1930s were when new trends became prominent in Korean housing architecture. This study began with a curiosity about the appearance of residential gardens during the transition period, when housing types were changing. Since gardens are constantly evolving and living spaces, it is not easy to give a clear picture of their evolution. However, through popular magazines and newspaper articles published in the 1920-30s, this study investigated how people perceived the gardens socially and how they engaged in gardening. First, the study of Gyeongseong's urbanization process revealed that people perceived gardens as a way to give natural beauty to the urban environment. Therefore, the creation of a residential garden was strongly encouraged. Second, the housing improvement movement, which the architects actively discussed during this period, emphasized that a garden is a factor that can help improve the quality of the residential environment in terms of hygiene and landscape aesthetics. Third, since the media provided information on gardening, it was confirmed that the number of people engaged in gardening as a hobby increased. As designers and gardeners who had received a modern education became more active, the concept of "designed gardens" was formed. Lastly, although the houses were divided into various types, the shapes of the gardens did not show a significant difference according to the architecture type. They tended to embrace the time's ideal garden design and style. Therefore, even in a traditional hanok, Western-style gardens were naturally harmonized into the overall architecture, and exotic plant species could be found. Although the gardens found in media images were limited to those belonging to the homes of the intelligentsia, it can be seen that representativeness was secured, considering the popularity and ripple effect of the media. Therefore, this study contributes to the literature as it confirmed the ideal gardens and gardening methods in the 1920s and 30s.

• Korean Journal of Poultry Science
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• v.44 no.2
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• pp.143-149
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• 2017

This study was carried out to collect basic data on the egg laying performance and disease occurrence on animal welfare-approved farms (AWAF) for laying hens with different housing types (windowless, open, and free-range house) and strains (Hy-line, Lohmann). Age at first egg laying was 151 d in the windowless house and 141 d in both the open and free-range houses, and the percentage peaks of each farm were 91.8%, 92.9%, and 86.3%. Average egg production according to housing types were 70.9%, 77.4%, and 65.6% at 18~38 wk old and 91.1%, 90.1%, and 76.2% at 32~36 wk. The average dirty and cracked egg ratio of the windowless, open, and free-range houses was 2.84%, 1.15%, and 0.23%, respectively. Mortality in the open house was lower than the other house types. Age of first egg laying for the Hy-line strain was 155 d and that for the Lohmann strain was 157 d, and the percentage peaks of the two strains were 92.9% (252 d) and 87.2% (237 d), respectively. Average egg production of the strains was 83.7% and 76.9%, respectively. The average dirty and cracked egg ratio of the Hy-Line and Lohmann strains was 3.85% and 2.97%, respectively. Mortality of the Hy-Line strain was lower than that of the Lohmann strain. There were significant differences (P<0.05) in the egg weight, HU, and egg yolk color of chickens raised in the open house compared with those of chickens raised in the other house types. In terms of antibody titer, that for Newcastle disease in open house chickens was lower than that of chickens raised in windowless and free-range houses. The antibody titer for low pathogenic avian influenza, avian infectious bronchitis, and avian pneumovirus was high at over 3.0 in all three farms. SG, Salmonella enteritidis, Salmonella pullorum, fowl adenovirus infection, and infectious laryngotrachitis were not detected in any of the three house types. The number of AWAF for laying hens has continuously increased in Korea, but there is currently little data on the housing types used on the AWAF for laying hens. Therefore, the results of the present study, in which analyzed the laying performance and disease occurrence on AWAF for laying hens, can use as basic data for the improvement of performance and prevention of disease on further AWFA for laying hens.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.395-399
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• 2017

The LPI fuel filter housings used in automobiles were made from conventional die castings but have recently been developed by cold forging to improve the weight and durability. On the other hand, a sink may develop at the core of the forged product due to the resulting T-shape, which not only reduces the aesthetics, but also increases the post-processing cost of the product. Therefore, this research focused on methods to predict and mitigate sink development and progression during the T-shape forging process. Finite element analysis of the forging process was first performed to determine the optimal initial workpiece devoid of burrs and underfills. An accurate sink prediction was then obtained via metal flow analysis, which was a result of the finite element simulation. Through finite element analysis, it was confirmed that sink development is a product of the differences in nodal velocities arising from the T-shaped forging process. Consequently, a pad was inserted beneath the sink to minimize these velocity differences. The results yielded significant improvement with regard to the sink defect. This method was practically applied to an industrial site to validate the sink improvement.