• Steel and Composite Structures
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• 제30권4호
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• pp.351-364
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• 2019

Earthquake and fire are both severe disasters for building structures. Since earthquake-induced damage will weaken the structure and reduce its fire endurance, it is important to investigate the behavior of structure subjected to post-earthquake fire. In this paper, steel-concrete composite beam-to-column joints were tested under fire with pre-damage caused by cyclic loads. Beforehand, three control specimens with no pre-damage were tested to capture the static, cyclic and fire-resistant performance of intact joints. Experimental data including strain, deflection and temperature recorded at several points are presented and analyzed to quantify the influence of cyclic damage on fire resistance. It is indicated that the fire endurance of damaged joints decreased with the increase of damage level, mainly due to faster heating-up rate after cyclic damage. However, cracks induced by cyclic loading in concrete are found to mitigate the concrete spalling at elevated temperatures. Moreover, the relationship between fire resistance and damage degree is revealed from experimental results, which can be applied in fire safety design and is worthwhile for further research.

• Earthquakes and Structures
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• 제21권6호
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• pp.627-639
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• 2021

Fragility curves are being more significant as a useful tool for evaluating the relationship between the earthquake intensity measure and the effects of the engineering demand parameter on the buildings. In this paper, the effect of different site conditions on the vulnerability of the structures was examined through the fragility curves taking into account different strength capacities of the precast columns. Thus, typical existing single-story precast RC industrial buildings which were built in Turkey after the year 2000 were examined. The fragility curves for the three typical existing industrial structures were derived from an analytical approach by performing non-linear dynamic analyses considering three different soil conditions. The Park and Ang damage index was used in order to determine the damage level of the members. The spectral acceleration (Sa) was used as the ground motion parameter in the fragility curves. The results indicate that the fragility curves were derived for the structures vary depending on the site conditions. The damage probability of exceedance values increased from stiff site to soft site for any Sa value. This difference increases in long period in examined buildings. In addition, earthquake demand values were calculated by considering the buildings and site conditions, and the effect of the site class on the building damage was evaluated by considering the Mean Damage Ratio parameter (MDR). Achieving fragility curves and MDR curves as a function of spectral acceleration enables a quick and practical risk assessment in existing buildings.

• Ocean Systems Engineering
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• 제13권4호
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• pp.385-399
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• 2023

A collision between a ship and an offshore platform may result in structural damage and closure; therefore, damage analysis is required to ensure the platform's integrity. This paper presents a damage assessment of a three-legged jacket platform subjected to ship collisions using the industrial finite element program Bentley SACS. This study considers two ships with displacements of 2,000 and 5,000 tons and forward speeds of 2 and 6.17 meters per second. Ship collision loads are applied as a simplified point load on the center of the platform's legs at inclinations of 1/7 and 1/8; diagonal bracing is also included. The jacket platform is modelled as beam elements, with the exception of the impacted jacket members, which are modelled as nonlinear shell elements with elasto-plastic material and constant isotropic hardening to provide realistic dented behavior due to ship collision load. The structural response is investigated, including kinetic energy transfer, stress distribution, and denting damage. The simulation results revealed that the difference in leg inclination has no effect on the level of localized denting damage. However, it was discovered that a leg with a greater inclination (1/8) resists structural displacement more effectively and absorbs less kinetic energy. In this instance, the three-legged platform collapses due to the absorption of 27.30 MJ of energy. These results provide crucial insights for enhancing offshore platform resilience and safety in high-traffic maritime regions, with implications for design and collision mitigation strategies.

• 대한공간정보학회지
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• 제22권4호
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• pp.71-80
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• 2014

본 연구에서는 강원도를 대상으로 산사태로 인한 피해지역을 사전에 예측하였으며, 도로, 건물, 산림 등의 피해규모를 지자체별로 산정하였다. 산사태를 예측하기 위해서 기존의 연구 성과를 활용하여 산사태 취약성도, 발생가능성도, 위험지도 제작기법을 정립하였다. 도로, 건물, 산림의 산사태 피해규모는 누적강우량 100mm, 200mm, 300mm 발생시 각각의 산사태 위험지도를 제작하여 지자체별로 산정하였다. 그 결과 100mm~200mm 미만 누적강우량 발생시 도로피해는 홍천군, 건물피해는 정선군, 산림피해는 홍천군 순으로 나타났으며, 200mm~300mm 미만 누적강우량 발생시 도로피해는 춘천시, 건물피해는 평창군, 산림피해는 홍천군 순으로 나타났다. 특히, 300mm 이상 누적강우량 발생시 홍천군의 경우 도로, 건물, 산림피해가 다른 지자체에 비해서 가장 피해가 클 것으로 예측되었다. 이와 같이 지자체의 산사태 피해규모를 각각 산정함으로써 산사태 예방의 우선순위 결정뿐만 아니라 예산을 투입하는데 있어 의사결정의 기초자료가 될 수 있을 것으로 기대된다.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1998년도 한국생물과학협회 학술발표대회
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• pp.113-113
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• 1998

In Saccharomyces cerevisiae UV irradiation and a variety of chemical DNA -damaging agents induce the transcription of specific genes, including several involved in DNA repair. One of the best characterized of DNA -damage inducible genes is PHRI, which encodes the apoenzyme for DNA photolyase. Basal-level and damage-induced expression of PHRI require an upstream activation sequence, UASPHRI. Here we report the identification of the UlvIE6 gene of S. cerevisiae as a regulator of UASPHRl activity. Surprisingly, the effect of deletion of UME6 is growth phase dependent. In wild-type cells PHRI is induced in late exponential phase, concomitant with the initiation of glycogen accumulation that precedes the diauxic shift. Deletion of UNIE6 abolishes this induction, decreases the steady-state concentration of photolyase molecules and PHRI mRNA, and increases the UV sensitivity of a rad2 mutant. The results suggest that UM E6 contributes to the regulated expression of a subset of damage-responsive genes in yeast. Furthermore, the upstream repression sequence, URSPHRI, is required for repression and damage-induced expression of PHRl. Here we show identification of YER169W and YDR096W as putative regulators acting through $URS_{PHRI}$. These open reading frames were designated as RPHI (YERl69W) and RPH2 (YDR096W) indicating regulator of PHRI. Simultaneous disruption of both genes showed a synergistic effect, producing a four-fold increase in basal level expression and a similar decrease m the induction ratio following treatment of methyl methanesulfonate(MMS). Mutation of the sequence ($AG_4$) bound by Rphlp rendered the promoter of PHRI insensitive to changes in RPHI or RPH2 status. The data suggest that RPHI and RPH2 act as damage-responsive negative regulators of PHRI. Surprisingly, the sequence bound by Rphlp in vitro is found to be $AG_4$ which is identical to the consensus binding site for the regulators Msn2p and Msn4p involved in stress-induced expression. Deletion of MSN2 and MSN4 has little effect on the induction$.$ ratio following DNA damage. However, all deletions led to a significant decrease in basal-level and induced expression of PHRI. These results imply that MSN2 and MSN4 are positive regulators of P HRI but are not required for DNA damage repression. [Supported by grant from NIH]om NIH]

• 한국자원식물학회지
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• 제24권2호
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• pp.130-138
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• 2011

본 연구에서는 열수 팥 추출물이 hydroxyl 라디칼에 의해 유도되는 산화적 스트레스에 미치는 영향을 알아보기 위하여 항산화활성과 DNA 및 세포의 산화적 손상 억제 효과를 조사하였다. 팥 열수 추출물의 DPPH 라디칼과 hydroxyl 라디칼의 제거능은 다소 낮았으나, $Fe^{2+}$-chelating과 과산화수소 제거효과는 높게 나타나 활성산소의 생성을 억제하는 데 효과적인 것으로 확인되었다. 또한 팥 열수 추출물의 in vitro DNA cleavage, DNA migration 및 H2AX의 인산화비 억제활성은 높은 활성을 보여주고 있어 라디칼에 의한 DNA 손상 억제에 효과적으로 작용하였다. 또한 지질과산화와 p21의 발현율을 통해 세포의 산화적 손상에 미치는 영향을 살펴보면 지질과산화 억제능과 p21의 발현율에 매우 효과적으로 작용하고 있어 라디칼에 의한 산화적 스트레스로부터 세포를 보호할 것으로 생각된다.

• 대한토목학회논문집
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• 제30권3A호
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• pp.309-316
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• 2010

이 논문에서는 인장과 압축하중에 놓은 무근 콘크리트와 철근콘크리트 구조물의 거동을 모사하기 위해 비국소화 이방성 손상모델을 제안하였다. 손상변수로써 대칭형의 이차 텐서을 사용한 연속체 손상모델에 기초한다. 콘크리트와 같은 준-취성재료에 있어 손상양상은 인장부와 압축부에서 다른 양상을 나타낸다. 이러한 두 개의 손상영역은 전체 변형률 텐서의 주변형률 성분을 손상텐서 속도에 비례하는 손상진전 법칙을 이용하여 모델링하였다. 제안된 모델의 유효성을 검토하기 위해 nooru-mohamed에 의해 실시된 이중 노치가 있는 시험체와 철근콘크리트 휨 시험체를 대상으로 해석을 수행하였다. 해석결과, 비국소화 이방성 모델은 혼합모드 파괴에 대한 균열진전을 적절히 모사할 수 있었으며 철근콘크리트 휨 시험체의 구조적 파괴에 있어서도 높은 수준의 콘크리트 손상 및 철근의 항복까지를 해석할 수 있었다.

• Radiation Oncology Journal
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• 제11권2호
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• pp.193-203
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• 1993

In understanding radiosensitivity a new concept of inherent radiosensitivity based on individuality and heterogeneity within a population has recently been explored. There has been some discussion of possible mechanism underlying differences in radiosensitivity between cells. Ataxia telangiectasia (AT), a rare autosomal recessive genetic disorder, is characterized by hypersensitivity to ionizing radiation and other DNA damaging agents at the cellular level. There have been a lot of efforts to describe the cause of this hypersensitivity to radiation. At the cellular level, chromosome repair kinetics study would be an appropriate approach. The purpose of this study was to better understand radiosensitivity En an approach to investigate kinetics of induction and repair of $G_2$ chromatic bleaks using normal, AT heterozygous (ATH), and AT homozygous lymphoblastoid cell lines. In an attempt to estimate initial damage, $9-{\beta}-D-arabinosyl-2-fluoroadenine,$ an inhibitor of DNA synthesis and repair, was used in this study. It was found from this study that radiation induces higher chromatid breaks in AT than in normal and ATH cells. There was no significant differences of initial chromatid breaks between normal and ATH cells. Repair kinetics was the same for all. So the higher level of breaks in AT $G_2$ cells is thought to be a reflection of the increased initial damage. The amount of initial damage correlated well with survival fraction at 2 Gy of cell survival curve following radiation. Therefore, the difference of radiosensitivity in terms of $G_2$ chromosomal sensitivity is thought to result from the difference of initial damage.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.216-218
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• 2022

이상 기후로 인한 자연 재해는 지속적으로 증가하고 있으며, 자연재해 중 가장 많은 피해를 입히는 유형은 폭우, 태풍 등으로 인한 수해 피해로 이러한 재해는 홍수를 동반하여 더욱 큰 피해를 입히기도 한다. 따라서, 홍수 피해를 줄이기 위해 본 논문에서는 LSTM과 GRU를 활용하여 실시간으로 홍수의 주요 파라미터인 수위를 실시간으로 예측할 수 있는 시스템을 제안한다. 홍수 예측을 위해 사용된 입력 데이터는 하천의 상류 및 하류 수위, 기온, 습도, 강수량이 사용되며, 사전에 학습된 LSTM-GRU 모델을 통해 실시간 예측을 진행한다. 입력 데이터는 과거 20시간의 데이터를 활용하여 향후 3시간의 수위를 예측한다. 본 논문에서 제안한 시스템을 통해 위험도 판별 기능을 추가하고 홍수에 노출된 사람들에게 대피 명령을 내릴 수 있다면 홍수로 인한 많은 피해를 줄일 수 있을 것으로 사료된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1025-1026
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• 2008

The level crossing collision accident which comprises more than 90 percent of all level crossing accidents is one of the most serious safety problems. There is a critical need for providing safe strategy and is focusing on the level crossing information rather than measures at a grade crossing. This study is intended to develop technology for accident prevention and damage reduction based on accident cases analysis result and improvement direction to complement shortcomings of safety equipment of conventional level crossing and to establish safety of travelers(train, motor vehicle, person).