• Earthquakes and Structures
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• 제5권1호
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• pp.1-22
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• 2013

Soft storey failure mechanism is a common collapse mode for masonry-infilled (MI) reinforced concrete (RC) buildings subjected to severe earthquakes. Simple analytical equations correlating global with local ductility demands are derived from pushover (PO) analyses for seismic assessments of regular MI RC frames, considering the critical interstorey drift ratio, number of storeys and lateral loading configurations. The reliability of the equations is investigated using incremental dynamic analyses for MI RC frames of up to 7 storeys. Using the analytical ductility relationship and a coefficient-based method (CBM), the response spectral accelerations and period shift factors of low-rise MI RC frames are computed. The results are verified through published shake table test results. In general applications, the analytical ductility relationships thus derived can be used to bypass the onerous PO analysis while accurately predicting the local ductility demands for seismic assessment of regular MI RC frames.

• Korean Journal of Radiology
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• 제21권10호
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• pp.1126-1137
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• 2020

Imaging plays a key role in the management of brain tumors, including the diagnosis, prognosis, and treatment response assessment. Radiomics and deep learning approaches, along with various advanced physiologic imaging parameters, hold great potential for aiding radiological assessments in neuro-oncology. The ongoing development of new technology needs to be validated in clinical trials and incorporated into the clinical workflow. However, none of the potential neuro-oncological applications for radiomics and deep learning has yet been realized in clinical practice. In this review, we summarize the current applications of radiomics and deep learning in neuro-oncology and discuss challenges in relation to evidence-based medicine and reporting guidelines, as well as potential applications in clinical workflows and routine clinical practice.

• 한국농공학회논문집
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• 제62권2호
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• pp.97-109
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• 2020

Drought is one of the most influential disasters in sustainable agriculture and food security of nations. In order to preemptively respond to agricultural droughts, vulnerability assessments were conducted to predict the possibility of drought in the region, the degree of direct or indirect damage, and the ability to cope with the damage. Information on agricultural drought vulnerability status of different regions is extremely useful for implementation of long term drought management measures. The purpose of this study is to develop and implement a quantitative approach for measuring agricultural drought vulnerability at sub-district level based on agricultural water and reservoirs. To assess the vulnerability in a quantitative manner and also to deal with different physical and socioeconomic data on the occurrence of agricultural drought, we selected the appropriate factors for the assessment of agricultural drought vulnerability through preceding studies, and analyzed the meteorological and agricultural reservoir data from 2015 to 2018. Each item was weighted using AHP (Analytic Hierarchy Process) analysis and evaluated through the agricultural drought vulnerability estimation. The entire national vulnerability assessments showed that Ganghwa, Naju, and Damyang were the most vulnerable to agricultural droughts. As a result of analyzing spatial expression, Gyeongsang-do is relatively more vulnerable to drought than Gangwon-do and Gyeonggi-do. The results revealed that the methodology and evaluation items achieved good performance in drought response. In addition, vulnerability assessments based on agricultural reservoir are expected to contribute supporting effective drought decisions in the field of agricultural water management.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.644-647
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• 2004

Modulus of rupture (MOR) and flexural toughness in hybrid fiber reinforced cement pastes mixed with micro-fiber (carbon fiber) and macro-fiber (steel fiber) and replaced with silica fume according to the fixed ratio were researched. Reinforcing efficiency in specimens were estimated by two factors, such as strengthening factor $(F_s)$ and toughening factor $(F_t)$, which were calculated from the analysis of variance (ANOVA) of the response values, such as MOR and absorbtion energy $(W_0)$. According to the experimental design by the fractional orthogonal array, nine hybrid fibrous reinforced paste series and one non-reinforced control paste were manufactured. Specimens of each series were tested by the INSTRON Inc. 8502(model) equipment in three-points bending and then measured the load-deflection response relationships. Considerable strengthening of cement pastes resulted in' the case of other factors without carbon fiber and toughening of cement pastes about all factors showed high. Based on the significance of factors related to response values from ANOVA, following assessments were available; $F_s$ or MOR: silica fume $\gg$ steel fiber $\gg$ carbon fiber; $F_t\;or\;W_0$: steel fiber > carbon fiber > silica fume. Optimized composition condition was estimated by steel fiber of $1.5\%$, carbon fiber of $0.5\%$ and silica fume $7.5\%$ in side of strengthening and steel fiber of $1.5\%$, carbon fiber of $0.75\%$ and silica fume $7.5\%$ in side of toughening.

• 한국화재소방학회논문지
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• 제34권1호
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• pp.89-102
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• 2020

인체 건강에 치명적인 위해를 가할 수 있는 독성 및 인화성 가스를 이용한 화학테러행위는 행위자인 테러범과 그 행위로 인한 피해자 간에 존재하는 현격한 정보의 비대칭성으로 인해 대다수의 선진국, 또는 국지적 분쟁을 겪고 있는 국가 및 지역사회에 대하여 중대한 안보위협이 되고 있다. 화학테러에 대한 대응기관의 대처방안은 크게 예방, 대응, 수습의 3단계로 나누어 볼 수 있고, 이 과정 중에서 화학테러의 피해 정도 및 피해 범위에 절대적인 영향력을 미치는 예방과 대응단계에 해당하는 각 전문대응기관과 요원들의 성공적인 임무수행을 위해서는 화학테러의 잠재적 대상이 되는 시설들에 대한 객관적이고 체계화된 취약성의 평가와 등급화가 무엇보다 중요하다. 본 연구에서는 기존 국내외의 화학테러관련 취약성 등급분류체계를 비교분석하고 현재 국내 등급분류체계의 개선방향에 대해 살펴보고 실제 국내 다중이용시설 표본에 대한 취약성 평가를 통해서 보다 과학적이고 체계화된 방법론을 제시하였다.

• 한국자동차공학회논문집
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• 제24권5호
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• pp.596-604
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• 2016

In this study, we used a stochastic approach for guaranteeing the reliability and robustness of the performance with regard to the design of polymer components, while taking into consideration the degradation properties and operating conditions in automobiles. Creep and tensile tests were performed for obtaining degradation properties. The Prony series, which described the viscoelastic models, were calculated to use the creep data by the Maxwell fluid model. We obtained the stress data from the frequency response analysis of the polymer components while considering the degradation properties. Limit state functions are generated by using these data. Reliability assessments are conducted under the variation of the degradation properties and area of frequency at peak response. For this study, the input parameters are assumed to be a normal distribution, and the reliability under the yield stress criteria is evaluated by using the Monte Carlo Simulation. As a result, the reliabilities, according to the three types of polymer materials in automotive components, are compared to each other and suggested the applicable possibility of polymeric materials in automobiles.

• 한국전산구조공학회논문집
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• 제33권6호
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• pp.401-409
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• 2020

확률론적 지진취약도 평가는 구조물 혹은 기기의 손상확률을 각 취약도 변수별 조합을 통해 이루어진다. 지진취약도로부터 구해지는 2개 이상 기기의 동시손상확률 계산은 기존에는 각 기기의 손상확률을 독립으로 가정해 왔다. 하지만 기기별 손상확률에 상관성이 있으며, 이를 평가한 결과 상관성에 따라 동시손상확률이 변화할 수 있는 결과를 보였다. 이 지진상관성을 무시하면 비보수적인 결과가 나오고 따라서 이를 고려해서 계산되어야 한다. 이 연구에서는 지진상관계수를 해석적으로 평가하기 위해 몇 가지 확률 변수를 선정하여 각 변수별로 혹은 통합하여 평가하고 그 차이를 비교했다. 그리고 단순화된 모델과, 복잡한 모델에 대한 상관계수 차이도 비교하였다. 이들 방법에 따른 상관계수의 결과와 차이를 분석했다. 그 결과 각 변수별로 평가하는 것과 통합하여 평가할 때 변수별 영향의 차이에 따라 상관성이 변화함을 확인하였고, 모델이 단순할수록 상관성이 높아짐을 확인하였다.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.1949-1958
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• 2023

The International Commission on Radiological Protection (ICRP) Publication 116 was released to provide a comprehensive dataset of the dose coefficients (DCs) for external exposures produced with the adult reference voxel phantoms of ICRP Publication 110. Although an advanced skeletal dosimetry method for photons and neutrons using fluence-to-dose response functions (DRFs) was introduced in ICRP Publication 116, the ICRP-116 skeletal DCs were calculated by using the simple method conventionally used (i.e., doses to red bone marrow and endosteum approximated by doses to spongiosa and/or medullary cavities). In the present study, the photon and neutron DRFs were used to produce skeletal DCs of the ICRP-110 reference phantoms, which were then compared with the ICRP-116 DCs. For photons, there were significant differences by up to ~2.8 times especially at energies <0.3 MeV. For neutrons, the differences were generally small over the entire energy region (mostly <20%). The general impact of the DRF-based skeletal DCs on the effective dose calculations was negligibly small, supporting the validity of the ICRP-116 effective DCs despite their skeletal DCs derived from the simple method. Meanwhile, we believe that the DRF-based skeletal DCs could be beneficial in better estimates of skeletal doses of individuals for risk assessments.

• Structural Monitoring and Maintenance
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• 제10권3호
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• pp.207-220
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• 2023

The safety of bridges are critical in our transportation infrastructure. Bridge design and analysis require complex structural analysis procedures to ensure their safety and stability. One common method is to calculate the maximum moment in the girders to determine the appropriate bridge section. Girder distribution factors (GDFs) provide a simpler approach for performing this analysis. A GDF is a ratio between the response of a single girder and the total response of all girders in the bridge. This paper explores the significance of GDFs in bridge analysis and design, including their importance in the evaluation of existing bridges. We utilized Bridge Weigh-in-motion (B-WIM) measurements of five simple supported girder bridge in Indonesia to develop a simple GDF provisions for the Indonesia's bridge design code. The B-WIM measurements enable us to know each girder strain as a response due to vehicle loading as the vehicle passes the bridge. The calculated GDF obtained from the B-WIM measurements were compared with the code-specified GDF and the American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) bridge design specification. Our study found that the code specified GDF was adequate or conservative compared to the GDF obtained from the B-WIM measurements. The proposed GDF equation correlates well with the AASHTO LRFD bridge design specification. Developing appropriate provisions for GDFs in Indonesian bridge design codes can provides a practical solution for designing girder bridges in Indonesia, ensuring safety while allowing for easier calculations and assessments based on B-WIM measurements.

• 한국과학교육학회지
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• 제35권5호
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• pp.907-917
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• 2015

중재반응 모형을 적용하여 예방차원의 효과적인 중재를 제공하는 것을 목표로 한다. 학습부진 요인을 인지적 요인, 정의적 요인, 환경적 요인으로 나눠 학습부진 유형을 파악하고, 과학 교과의 특성을 고려하여 과학 탐구 능력 및 과학적 태도 검사를 실시하여 학습부진아에 적합한 지도방안을 모색하고 학습부진 유형별 맞춤형 프로그램을 개발 및 적용하였다. 교육과정 중심측정 및 학업 성취도 검사를 실시하여 학습부진아의 수행수준 및 진전도를 파악하고 과학에 대한 태도 및 과학학습동기 검사를 사전-사후 실시하여 과학에 대한 정의적인 측면에서 맞춤형 학습부진아 지도의 효과를 알아보았다. 수집된 자료의 효과를 검증하기 위해 학업 성취도 검사 및 교육과정 중심 측정 검사를 실시하여 단일 회귀분석 중 선형분석을 이용하였다. 연구 결과는 다음과 같다. 첫째, 1단계 일반 교수를 적용하여 과학학습부진아의 수행수준과 진전도를 보면, 수행수준과 진전도에서 진전을 보였으나 학년수준에 미치지 못하는 아동과 수행수준과 진전도에서 변화를 보이지 않는 아동이 있었다. 둘째, 2단계 맞춤형 학습 부진아 지도를 적용하여 과학학습부진아는 학업능력이 크게 향상되었다. 셋째, 과학 학습 부진유형에 따른 맞춤형 학습 부진아 지도가 과학학습부진아의 과학에 대한 태도 및 과학 학습 동기에 긍정적인 영향을 미쳤다. 이와 같은 연구결과를 통해 과학 학습 부진 유형에 따른 맞춤형 학습 부진아 지도프로그램을 과학학습부진아에 적용하여 학업 성취도 및 과학에 대한 태도, 과학학습동기에 긍정적인 영향을 미쳤음을 알 수 있다.