• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.4
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• pp.205-213
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• 2019

In the Pohang Earthquake in 2017, considerable damage to non-structural elements, such as ceiling systems, exterior finishes, and curtain walls, was reported; thus, the seismic designs of non-structural elements are important. In this study, the modal characteristics of a ceiling system were investigated through the impact hammer test. The frequency and damping ratio according to the length of the hanger bolt were identified. In addition, collision experiments were conducted to obtain the impact duration for exactly considering the impact effects of the ceiling against a wall or other adjacent elements. Based on the identified dynamics and impact duration of the ceiling system, the seismic responses of the ceiling system were obtained numerically in case of collision. Numerical simulation results show that the impact load tends to increase with the clearance between the ceiling and adjacent elements, and is not correlated with the length of the hanger bolt.

• The Journal of the Convergence on Culture Technology
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• v.8 no.1
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• pp.461-468
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• 2022

This study is focused on the ignition of ceiling insulation depending on working condition of Sprinkler head in underground parking lot fire. When temperature changes of same point were measured depending on sprinkler's working condition, in Scenario 1, inner temperature at border of spray applied material(SP-2) of ceiling part near the fire and ceiling insulation(blowing polystyrene) was 658.27℃ and its which inner maximum temperature is higher than 427℃ which is the ignition point of ceiling insulation(blowing polistyrene), so it was observed that flame is ignited on the ceiling insulation and spread fire. In scenario 2, Inner fire temperature at border of spray applied material(SP-2) and ceiling insulation(blowing polystyrene) near the fire was 53.10℃ and it was lower than ignition point so it was observed that flame was not ignated on the ceiling insulation. As a result, it was foreseen that possibility of ignition on the ceiling insulation depending on working condition of sprinkler.

• The Journal of Sustainable Design and Educational Environment Research
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• v.15 no.1
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• pp.11-18
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• 2016

The purpose of this study is to develop the evaluation model of school facilities in terms of seismic performance during safety education in the school field. This study is composed of four stages with a view to developing user oriented evaluation models that can be utilized during earthquake safety education on ceiling system. and First stage analyze the evaluation guidelines to find evaluation methods and items. Based on the items, site survey was conducted to derive the characteristics of seismic performance of domestic school buildings in terms of ceiling system. Third stage analyzes the seismic performance of ceiling system. Final stage is to derive recommendations based on the results.

• The Journal of the Acoustical Society of Korea
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• v.37 no.5
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• pp.323-330
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• 2018

This study investigated effects of absorbent gypsum board in the ceiling on low-frequency heavyweight floor impact sound through sound absorption coefficient and floor impact sound measurement. The sound absorption coefficients were measured with sound absorbent gypsum board, glass wool on gypsum board, and a double panel absorbent gypsum board (absorbent gypsum board + glass wool + absorbent gypsum board). Result showed that the absorbent gypsum board had sound absorption coefficient of 0.1 ~ 0.7 from 200 and 630 Hz octave band. The sound absorption coefficient was increased in all frequency range by adding glass wool. Additional absorbent gypsum board increased sound absorption coefficient up to 250 Hz octave band, but decreased over 250 Hz. Heavyweight floor impact sounds were measured in test building for three materials above, gypsum board, and bare slab. Result showed that glass wool on gypsum board and a double panel absorbent gypsum board reduced by 3 dB ~ 4 dB (single number quantity) heavyweight floor impact sound. Comparing with bare slab condition, floor impact sound reduction was mainly found from 125 Hz to 500 Hz octave band, and the maximum reduction was shown in the 250 Hz octave band.

• Proceedings of the Acoustical Society of Korea Conference
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• 1993.06a
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• pp.13-16
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• 1993

본 연구에서는 공동주택의 바닥충격음 차음성능 향상을 위한 설계자료의 제시를 위해 천장구조가 서로 다른 공동주택을 대상으로 경량 및 중량 바닥충격음의 현장측정을 통하여 공동주택의 천장구조에 의한 바닥충격음 변화특성을 분석하고 차음성능을 평가하였다. 측정대상 건물에서 천장을 설치한 경우가 비교적 높은 충격음 차음성능 분포를 보이는 것으로 나타났으며, 바닥슬래브 하부 천장에 공기층과 완충재를 함께 설치하는 것은 기존 공동주택 등에서 경량 및 중량 바닥충격음 차음성능을 향상시키기 위한 효과적인 방안임을 확인하였다.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.1
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• pp.59-65
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• 2010

The purpose of this study is to analyze the risk of the forest fire, considering the topography and the forest, for establishing disaster prevention measures of cultural heritage, Uireung, over in Cheonjang-mountain. To do that, we estimate the occurrence and spread of the forest fire over in Cheonjang-mountain through a forest fire probability model(logistic regression), using the space characteristic data($100m{\times}100m$). The factor, occurrence of the forest fire, are diameter class, southeast, southwest, south, coniferous, deciduous, and mixed forest. We assume the probability of the fire forest in each point as follow : [1+exp{-(-4.8081-(0.02453*diameter class)+(0.6608*southeast)+(0.507*southwest)+(0.7943*south)+(0.29498*coniferous forest)+(0.28897*deciduous forest)+(0.17788*mixed forest))}]$^{-1}$. To divide dangerous zone of the big forest fire, we make the basic materials for disaster prevention measures, through the map of coniferous forests, deciduous forests, and mixed forest. The damage of cultural heritage caused by a forest fire will be reduced through the effective preventive measures, by forecast a forest fire to using this study.

• Korean Journal of Heritage: History & Science
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• v.47 no.2
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• pp.68-84
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• 2014

The royal tombs of Baekje(백제), after the transfer of the capital to the Geumgang(riv)(금강) basin, changed to Songsanri(송산리) style(stone chamber) ${\rightarrow}$ Southern dynastic(남조) style(brick chamber) ${\rightarrow}$ Neungsanri(능산리) style(stone chamber). The most special feature of this process is the change of the ceiling structure. The ceiling had been changed from dome(Songsanri style) ${\rightarrow}$ tunnel ceiling(transition period of brick tombs and Neungsanri style) ${\rightarrow}$ a roof style(is Neungsanri style of three imitate type, trapezoid, triangle, flattened ceiling). The most special feature among this process is Neungsanri style(stone chamber), created especially in Baekje. The royal tombs of Baekje didn't lay stress on the mound, so the mound is not noticeable. It is result that they more stressed on basin of the boundary than showed off individual tomb, and this is count as an element of China Southern dynasty. Boundary of the royal tomb of Baekje, after the transfer of the capital to south, were changed from royal family's boundary to single independent's. Those are Songsanri's and Neungsanri's, these are the pair tombs(쌍릉) of Iksan(익산). That is influence of the Southern dynasty, reflect the theory of divination based on topography completely, this is influence of the China Sui(수) and the early Tang(당) dynasty's system of boundary of the royal tomb. Besides the royal tomb, they also buried a closely related person, in the boundary of the royal tomb. And facilities for memorial ceremony were existed too. An altar was equipped in Songsanri's boundary of the royal tomb, it was seen a kind of character of a sanctuary for progenitor. Neungsanri's boundary of the royal tomb were equipped with an open-aired altar that performed memorial ceremony about communal royal tombs, and also equipped a temple, was needed to pray for the happiness of the dead. This structure and arrangement are very similar to Seoakdong(서악동) of Silla(신라).

• The Journal of the Korea Contents Association
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• v.21 no.8
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• pp.376-387
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• 2021

This study is to analyze the research trends related to the 'glass ceiling' phenomenon using big data analysis methods and to suggest social implications. To analyze the research trends of 'glass ceiling', the historical event that broke the 'glass ceiling' was set as an important issue, and keywords were collected by dividing park's term into three. Before, throughout and after, her term. As a result of frequency analysis, research was conducted based on 'public servants' which was selected as the main keyword in the first period, while 'women's work family compatibility' was chosen as the main keyword group in the second period. In the third period, keywords for women's occupational groups were being diversified. As a result of applying CONCOR techniques to make the studied main topics grouped, we were able to confirm that the main issues were the differentiating factors, the customary gender discrimination culture, the jobs aimed for studying, the work-family balance, the glass ceiling and the organizational performance adjustment factors, the public sector, organizational performance, and the private sector. Besides work-family compatibility support system, it was suggested as a social implication that research on improving the system to resolve the glass ceiling factor and to expand the target jobs to give solutions to real-life issues were needed, and also suggested that research on the 'glass ceiling' which the general public perceives through social medias or articles in the news, was needed in the future.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.42-45
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• 2008

다목적 공간 및 공연장은 공연 또는 강연을 위한 공간뿐만 아니라 상점, 식당 및 체육 공간 등 다양한 용도의 공간이 인접되고 있다. 다양한 공간이 인접할 경우 기존의 다목적 공연장에서는 발생하지 않았던 다양한 소음 진동 문제들이 발생한다. 본 연구는 강연 및 공연을 위한 다목적 공간 상부에 식당 및 체육 시설로 활용되는 공간이 배치되어 바닥충격음 문제가 발생할 가능성이 있었다. 바닥충격음의 강당으로의 전달을 차단하기 위하여 기본 구조체에 대한 바닥충격음 차단성능을 측정하여 적절한 저감 대책을 수립하였다. 저감대책으로는 상층부 철골 슬래브와 강당의 철골 구조의 구조적 분리, 유연한 마감재 적용, 슬래브로의 충격진동 차단을 위한 제진재 적용, 이중천장 구조 및 천장내부 흡음구조 형성 등의 종합적인 대책을 수립하였다. 이를 통해 경량충격음 및 중량충격음을 효율적으로 차단하였다. 또한 강당 공간은 강연 및 집회의 공간으로 활용될 수 있도록 하기 위하여 적절한 잔향시간 및 음성 명료도 확보가 필요하다. 플러터 에코, 과도한 잔향시간, 음의 사각지대 등을 최소화하기 위하여 측벽 형태 개선, 천장 반사판 형태를 개선하였다. 또한 측벽에서 진동 등의 영향으로 발생되는 떨림현상을 억제하기 위하여 측벽 내부를 흡음재로 충전하는 등의 대책을 수립하여 적용하였다.

• Fire Science and Engineering
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• v.25 no.4
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• pp.22-27
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• 2011

Fire resistance ceiling system is the structure of which the ceiling installed under the slave of the structure has the fire resistance performance. Because of having the fire resistance performance, fire resistive coatings on steel beams can be reduced and large span structures can be constructed. So, it have advantages of convenience for construction, shorten for construction time and cost reducing. In foreign country, it is general that one system consisting of slave and ceiling is constructed as a fire resistance system. But in Korea, there are no fire resistance ceiling systems thus economical efficiency due to being high-rise and light-weight of structures is not secured. Therefore research and development of nominal fire resistance ceiling systems is necessary. On this study, fire resistances of standard non-loadbearing ceiling systems were assessed and basic informations for developing the fire resistance non-loadbearing ceiling systems were presented.