• Journal of the Korean Society for Railway
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• v.16 no.5
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• pp.358-364
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• 2013

In the second part of the paper, a design strategy for an apartment complex constructed at a railway depot is proposed for vibration reduction purposes. Various design parameters such as the vehicle operating speeds, artificial land behavior, housing support structure, and apartment sub-structures are individually examined to reduce the transmission of vibrations through building structures. Building construction on an artificial land should be subjected to regulations that require the application of a vibration reduction scheme based on the mechanics that govern the vibration transmission phenomena. The implementation of these parameters at an early design stage will provide a quiet living environment for residents who may be exposed to excessive noise and vibration.

• Journal of the Korean Society for Railway
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• v.16 no.5
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• pp.353-357
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• 2013

Property development along railway lines is a critical issue at present. Because various railway lines exist in most large cities, there are numerous properties and open spaces to be developed for communities associated with these lines. The active development of railway properties can be a means to resolve housing shortage problems in cities. In this first part of this paper, noise and vibration levels of an artificial area of land and apartment complex are measured and evaluated to derive a design strategy for vibration reduction purposes.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.547-548
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• 2023

내진 설계가 되어있지 않은 건물의 경우, 지진으로 인해 건물 붕괴 가능성이 높아지며 이로 인해 많은 인명 피해가 발생할 수 있다. 지진으로 인한 건물의 피해를 예측하고 이를 기반으로 취약점을 보완한다면 인명 피해를 줄일 수 있으므로 건물 피해 예측 모델에 대한 연구가 필요하다. 본 논문에서는 2015 년 네팔 대지진으로 인해 손상된 건물 데이터를 활용하여 Random Forest 와 Extreme Gradient Boosting 기계학습 분류 알고리즘을 사용하여 지진 피해 예측 모델의 정확도를 비교하였다.

• Journal of the Korean Geophysical Society
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• v.2 no.1
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• pp.27-38
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• 1999

The errors between track segments or at the cross-over points of shipborne gravity were successfully reduced by applying a cross-over error adjustment technique using satellite gravity. The integration of shipborne and satellite altimeter-implied free-air gravity anomalies after the cross-over error adjustment resulted in a high resolution gravity map which contains both short and long wavelength components. The successful adjustment of the cross-over errors in the shipborne gravity using the satellite gravity suggests that the shipborne gravity can be combined with the satellite anomalies characterized by a stable and long wavelength component. The resulting free-air anomaly map is evenly harmonized with both short and long wavelength anomalies. Thus the corrected anomaly map can be better used for the geological interpretation. Free-air anomalies with more than 140 mGal in total variations generally correspond to the seafloor topographic changes in their regional patterns. A series of gravity highs are aligned from the Korea Plateau to the Oki Island, which are interpreted to be caused by seamounts or volcanic topographies. The gravity minima along the western and southern shelf edge are associated not only with the local basement morphology and thick sediment fill at the continental margin, but also possibly with the crustal edge effect known for passive continental margins. Series of NE-trending linear anomalies are possibly caused by a swarm of volcanic intrusions followed the initial opening of the Ulleung Basin. The linear high anomalies in the Ulleung Plateau are terminated by the straightly NNW-trending anomalies with a sharp gradient in its western boundary which indicates a fault-line scarp. The opposite side adjoined with the fault-line scarp shows no correlation with the fault-line scarp in geometry indicating that the block might be horizontally slided from the north. A gravity high in contrast to the deepening in seafloor toward the northeastern central Ulleung Basin is probably responsible for the thin crust and shallow seated mantle. The gravity minima along the western and southern shelf edge are associated not only with the local basement morphology and thick sediment fill at the continental margin, but also possibly with the crustal edge effect known for passive continental margins. Series of NE-trending linear anomalies are possibly caused by a swarm of volcanic intrusions followed the initial opening of the Ulleung Basin. The linear high anomalies in the Ulleung Plateau are terminated by the straightly NNW-trending anomalies with a sharp gradient in its western boundary which indicates a fault-line scarp. The opposite side adjoined with the fault-line scarp shows no correlation with the fault-line scarp in geometry indicating that the block might be horizontally slided from the north. A gravity high in contrast to the deepening in seafloor toward the northeastern central Ulleung Basin is probably suggestive of a thin crust and shallow seated mantle.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.1
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• pp.56-60
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• 1997

In order to investigate the relationships between the responses of four crops (rice, soybeans, potatoes, and red pepper) to acid rain, the simulated acid rain(SAR) of pH 1.8, 2.3, and 2.8 and normal rain of pH 6.0 were applied from 30 days after emergence to harvest at the two-week interval for rice, soybeans and red pepper and at a week interval for potatoes. SAR of pH 1.8 and 2.3 caused brown spots in the leaves of rice, soybeans, and red pepper and the damages were severer as the pH of SAR lowered, while no visual damages were observed in potatoes. The SARs did not affect chlorophyll content of rice and potatoes, while chlorophyll content of soybeans and red pepper decreased as the pH of SAR lowered. Photosynthetic activity was not significantly different among the pHs of SAR in rice, while decreased as pHs of SAR lowered from pH 2.8 to 1.8 in soybeans, potatoes, and red pepper. Yield of rice, soybeans, and potatoes was not affected by the pHs of SAR, but in red pepper the length, diameter, and weight of a fruit, the number of fruits per plant, and total matured fruit yield decreased as the pHs of SAR lowered. In rice and potatoes visual damages caused by SAR did not correlated with other observed traits. However, visual damages were negatively correlated with chlorophyll content and photosynthetic activity of soybeans and photosynthetic activity and yield of red pepper.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.5
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• pp.31-38
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• 2008

Recently the necessity of time history analyses is increasing for the seismic analyses of a structure, and the seismic design provisions of IBC2003, ASCE and KBC2005 require the use of a minimum of seven earthquake records for the time history analyses. Earthquake records for the time history analyses could be selected from the database of the field-measured earthquake records having similar site conditions with the designed site, or from simulated sites satisfying the design spectrum. However, in this study seven earthquake records were generated using 50 earthquake records, classified as records measured at the rock, in the database of the Pacific Earthquake Research Center (PEER). Seven earthquake records were first selected by the least squares fitting method comparing the scaling factored response spectra with the specified design spectrum, and a family of seven artificial time history earthquake records was ultimately generated by multiplying scaling factors, which were calculated by the least squares fitting method and the SRSS averaging method, to the corresponding selected earthquake records.

• The Transactions of the Korea Information Processing Society
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• v.13 no.5
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• pp.217-220
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• 2024

Predicting earthquake occurrences accurately is challenging, and preparing all buildings with seismic design for such random events is a difficult task. Analyzing building features to predict potential damage and reinforcing vulnerabilities based on this analysis can minimize damages even in buildings without seismic design. Therefore, research analyzing the efficiency of building damage prediction models is essential. In this paper, we compare the accuracy of earthquake damage prediction models using machine learning classification algorithms, including Random Forest, Extreme Gradient Boosting, LightGBM, and CatBoost, utilizing data from buildings damaged during the 2015 Nepal earthquake.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.116-123
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• 2000

본 논문은 1995년 일본 남부 효고켄 남부 지진 (코베 대지진)에 의해 코베시에 위치하는 인공섬인 포트 아일랜등서 발생한 액상화 현상을 해석적 기법을 동원하여 액상화 현상의 저감 효과 혹은 방지를 위하여 실시되어져 오고 있는 여러 공법들의 타당성을 수치해석적인 입장에서 검증한 것이다. 따라서, 본 논문에서는 코베시에 의해 획득되어진 연직 방향의 지진 기록에 의해 포트 아일랜드 시공 당시 구역별로 다른 지반 개량 공법을 실시했고, 혹은 실시하지 않는 구역에 대해서 1차원 및 2차원 전응력 그리고 유효 응력 해석 기법을 동원하여 일련의 해석을 실시하였고 그 결과를 다각적인 방향에서 제시하였다.

• Magazine of the Korea Concrete Institute
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• v.14 no.5
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• pp.47-53
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• 2002

근래 지구촌의 산업화가 가속됨에 따라 대지의 활용도가 급속하게 증가하고 있으며 아울러 인구의 증가 및 개개인 삶의 공간적 범주가 점점 확대되면서 지구상에 광범위하게 분포되어 있는 연약지반으로의 관심이 집중되고 있는 실정이다. 최근 국내에서도 고속철도, 인천국제공항, 도심지 지하철 및 서ㆍ남해안 항만공사 등 대규모 국가건설공사가 진행 중에 있으며 더더욱 임해시설의 확충이라든지 인공섬 등의 건설이 활발해지면서 연약지반에 대한 관심이 고조되고 있다. 하지만 연약지반의 특성을 경시한 나머지 터널의 붕락, 주변지반 및 인접건물의 부등침하, 측방유동에 의한 구조물변위 등 대형 안전사고가 빈발하게 발생되어 왔다. 이러한 안전사고의 대책으로서 지반보강을 위한 여러 가지 신공법이 개발되었고, 새로운 터널보조공법이 국내 지하철건설현장에서 널리 쓰여지고 있으며 이러한 공법 등을 통한 성과도 적지 않게 보고되고 있다.(중략)

• Spatial Information Research
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• v.8 no.2
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• pp.275-288
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• 2000

The purpose of this study is to analyze relationship between the NDVI change pattern and landcover change pattern in the City of Sungnam during 1985 and 1996. The results of this study are as follows; (1) NDVI of the level 6 and 7 is decreased and the level 5 is increased in the area where Forst area changed to the other land cover during 1985 and 1996. (2) In the area where Agricultural-Pasture changed to forest, NDVI level became higher certainly during that time. But in the area where there has been changed from Agricultural-Pasture to Urban or built-up, Agricultural-Pasture to Barren land, the level of NDVI is decreased. (3) In the Urban or built-up to other land, or built-up the level of NDVI is increased. (4) In the area where Barren land changed to other land cover, the level of NDVI is increased.