• Nuclear Engineering and Technology
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• 제54권1호
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• pp.386-400
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• 2022

Seismic fragility analysis, a part of seismic probabilistic risk assessment (SPRA), is commonly used to establish the relationship between a representative property of earthquakes and the failure probability of a structure, component, or system. Current guidelines on the SPRA of nuclear power plants (NPPs) used worldwide mainly reflect the earthquake characteristics of the western United States. However, different earthquake characteristics may have a significant impact on the seismic fragility of a structure. Given the concern, this study aimed to investigate the effects of earthquake characteristics on the seismic fragility of concrete containments housing the OPR-1000 reactor. Earthquake time histories were created from 30 ground motions (including those of the 2016 Gyeongju earthquake) by spectral matching to the site-specific response spectrum of Hanbit nuclear power plants in South Korea. Fragility curves of the containment structure were determined under the linear response history analysis using a lumped-mass stick model and 30 ground motions, and were compared in terms of earthquake characteristics. The results showed that the median capacity and high confidence of low probability of failure (HCLPF) tended to highly depend on the sustained maximum acceleration (SMA), and increase when using the time histories which have lower SMA compared with the others.

• 디지털콘텐츠학회 논문지
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• 제19권9호
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• pp.1727-1737
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• 2018

본 논문에서는 토지피복도에서 공간구조를 검출하고 시계열 공간구조 변화를 검출하는 시스템을 제안한다. 서로 다른 시간의 토지피복도에서 패치를 검출하고 패치의 측정요소를 계산하여 공간구조 패턴을 분석한다. 검출된 시계열 패치에 대해 패치 매핑을 이용하여 유지, 생성, 소멸, 분할, 병합, 혼합적 변환 등의 변화 유형을 결정한다. 또한, 시계열 토지피복도의 패치 기반 공간구조 패턴을 이진으로 저장하여 변화를 추출하였다. 본 논문에서는 제안하는 토지피복도 공간구조 변화검출 시스템을 통해 해당 지역(도시)의 난개발 현상을 진단하고, 향후 도시공간구조의 재구축을 위한 계획수립에 근거 자료로 활용될 수 있음을 보여주고 있다.

• 한국환경복원기술학회지
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• 제9권6호
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• pp.13-22
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• 2006

The purpose of this study is to propose rational methods in order to maintain vegetation condition and soil environment based on the analysis of tree growth in relation to the soil environment, which is one of the most significant environmental factors on vegetation condition in urban parks and open spaces. The result of the study can be described as below;The soil on every study site had strong acidity. In particular, study sites around industrial district and central business district showed extreme soil acidity. Therefore, soil management system is needed in urban parks and green spaces around those areas. Among Cambium Electric Resistance classified by locations of urban parks and open spaces, one in the costal area was the lowest. The Cambium Electric Resistance in the industrial area was the highest. Therefore, soil condition and locational environment in the industrial area are highly related to the Cambium Electric Resistance. Among the factors, which affect Cambium Electric Resistance in different locations, inorganic content was found to be the main factor in all of the study sites. Inorganic content was an important factor to the Cambium Electric Resistance in study sites located in industrial and central business districts. In the study sites located in costal area, Soil acidity was found to be other important factors that affect Cambium Electric Resistance. To improve the soil acidity, soil buffering ability should be improved from activating microorganisms in the soil by using lime and organic material, Since it takes a long time to make a change in the soil structure, well planed maintenance system is required by mid-term or long-term plans.

• 도시과학
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• 제10권1호
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• pp.29-37
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• 2021

The number of old buildings older than 30 years in Korea continues to increase from 29.9% in 2005 to 38.8% in 2020. Considering the growing urban regeneration projects, urban maintenance projects, the suppression of urban expansion, and the lack of idle land in the city, the dismantling of old buildings is expected to increase further in the future. As major accidents at building dismantling sites continue to occur, related agencies are also strengthening safety management of building dismantling works. While physical safety management such as collapse and fall is strengthened, there is a relative lack of interest in the health of workers at dismantling sites due to environmental hazards. Since relevant laws stipulate that construction waste should be separated and discharged, old buildings need to be considered for environmental hazards such as fine dust, floating bacteria, and floating molds when dismantling. In this study, we intend to find important safety management elements in the management of building dismantling sites, measure environmental factors harmful to dismantling workers, and present basic data for the management of dismantling sites in the future. "Safety management" was the highest priority, followed by "dust," "vibration," "noise," "bacteria," and "smell." The perception of the importance of "physical damage prevention" with workers working on dismantling and managers managing the site came out similar, but the perception of "work efficiency" and "health disorder prevention" through environmental hazard management showed different priorities. In the process of dismantling, floating bacteria and floating mold were collected, cultured, and measured the concentration in the indoor air. The measurement was measured by dividing it into pre-dismantling and during dismantling.

• 대한토목학회논문집
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• 제33권6호
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• pp.2583-2591
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• 2013

국내 많은 도시들은 경제 성장률 하락에 따른 고용창출 하락, 출산률 감소에 따른 인구감소, 노령인구 증가에 따른 도시활력 감소, 도심 공동화에 따른 도시기능 쇠퇴 등 20세기에 겪어보지 못한 새로운 도시양상에 직면하고 있다. 이에 따라 이들 도시들은 도시의 당면한 문제를 해결하고 도시 경쟁력을 향상 시킬 수 있는 다양한 방안 중 하나로 창조도시에 대한 관심이 높아지고 있다. 창조도시는 주민들이 다양한 문화생활과 여가활동이 가능하고 혁신적인 산업을 진흥할 수 있는 장소가 풍부한 도시로서 과학자, 기술자, 건축가, 디자이너, 작가, 예술가, 음악가 등의 창조산업 인구에 의해 선도된다. 따라서 본 연구는 국내 도시를 인구규모별로 구분하여 어떠한 도시구조가 창조산업 인구와 관계가 있는지를 제시하는데 목적이 있다. 연구결과 광역시에서는 문화행사 수가 창조산업 인구와 관계가 있으며 대도시에서도 문화행사 수와 문화공간 수가 창조산업 인구에 영향을 미치는 것으로 나타났다. 한편 중소도시에서는 문화행사 수와 환경오염 관리시설이 창조산업 인구 유인에 영향을 미치는 것으로 나타났다. 따라서 창조산업 인구 유입에 가장 큰 영향을 미치는 요소가 도시문화임에 따라 도시 경쟁력을 강화하기 위해서는 다양한 도시문화 환경을 조성하는 것이 시급하다.

• 환경영향평가
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• 제21권5호
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• pp.781-787
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• 2012

The purpose of this study was to analyze the landscape changes at Su-ji and Gi-heung in Young-in city using FRAGSTATS Model. Landscape Indices obtained by this model can explain the structural change of urban green zone and fragmentation resulting from development. As results of this study, Gi-heung showed worse quality of landscape in 2007, comparing 2000. However, in Su-ji, there were several better landscape indices in the same 2007/2000 comparison, even though the little shrinking of green zone and separation of core area. It could assume that the reason was caused by conservation policy of urban green zone. This study could provide the useful methods for finding the problems and searching the alternatives considering the development of urban green zone.

• 한국환경보건학회지
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• 제34권3호
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• pp.247-254
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• 2008

Non-point source pollution that originates from surface applied chemicals in either liquid or solid form is a part of urban activities and it appears in the surface runoff caused by rainfall. This study investigates the characteristics of non point source pollution in relation to storm events and the first washing effect in the Study area, which is comprised of different land use types. Then, a Best Management Practices (BMP) model, for urban areas, is applied with the Storm water Management Model (SWMM) Windows Interface which was developed by the EPA in the USA. During the storm event analysis of the hydrographic and pollutographic data showed that the peak of pollutants concentration was within the peak flow, 30 to 60 minute into the storm event in the Study area. The results of simulation using SWMM Windows Interface, Structure Techniques as applied in the study were highly efficient for removal of pollutants. Predicted removal efficiency was 26.0% for SS, 22.1 for BOD, 24.1% for COD, 20.6% for T-N, and 21.6% for T-P, respectively.

• 한국경제지리학회지
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• 제17권4호
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• pp.848-863
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• 2014

최근에는 도시의 환경적, 경제적, 사회적 조화를 주제로 하는 문화 역사 정체성 생태 중심의 지속가능한 재생이 다양하게 제시되고 있다. 하지만, 도시 재생의 기반이 되는 도시 구조는 배제되어 있다. 이에 본 연구에서는 농 목축 지역을 배경으로 성장한 미국 텍사스주 러벅시의 도시 구조, 도시 및 재생 계획 분석을 기반으로 지속가능한 도시 재생에 접근하였다. 러벅시는 1950년대에 기존의 약 300%나 되는 시역 확장에도 불구하고, 1970년대 이후 남서부 및 서부로의 부유층 이전과 함께 도심 쇠퇴가 심화된다. 1980년대부터 주민 중심의 재개발을 위한 조직체가 구성되고, 민관기업 중심의 재생 계획 및 시행이 지속되고 있다. 본 연구에서는 최근의 도시 재생 관점, 도시 전체와의 연계라는 측면에서 지속 가능한 도시 재생 전략을 도출하였다.

• Smart Structures and Systems
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• 제33권3호
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• pp.177-188
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• 2024

The fatigue-induced sequential failure of a structure having structural redundancy requires system-level analysis to account for stress redistribution. System reliability-based design optimization (SRBDO) for preventing fatigue-initiated structural failure is numerically costly owing to the inclusion of probabilistic constraints. This study incorporates the Branch-and-Bound method employing system reliability Bounds (termed the B³ method), a failure-path structural system reliability analysis approach, with a metaheuristic optimization algorithm, namely grey wolf optimization (GWO), to obtain the optimal design of structures under fatigue-induced system failure. To further improve the efficiency of this new optimization framework, an additional bounding rule is proposed in the context of SRBDO against fatigue using the B³ method. To demonstrate the proposed method, it is applied to complex problems, a multilayer Daniels system and a three-dimensional tripod jacket structure. The system failure probability of the optimal design is confirmed to be below the target threshold and verified using Monte Carlo simulation. At earlier stages of the optimization, a smaller number of limit-state function evaluation is required, which increases the efficiency. In addition, the proposed method can allocate limited materials throughout the structure optimally so that the optimally-designed structure has a relatively large number of failure paths with similar failure probability.

• 한국환경복원기술학회지
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• 제6권5호
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• pp.70-78
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• 2003

From the viewpoint of the importance of the division theory based on topography(pyungsu) derived from the uniqueness in topography, not to mention of the function of ridge in ruban areas, the destroy of ridges should be prevented from the development of hill areas. This study intends to propose the basic concepts and principles to protect the ridge axis with green in open space and landscape planning. The main results are summarized as follows : First, eco-bridge across the ridges will be connected for the purpose of ecosystem restoration. Second, the protection and restoration of green ridge axis can be completed by Green Structure Plan which has principles and standards such as. - layout of development axis and establishment of rules on preservation - the practical use of various preservation methods and the standards suitable to the methods - laying down the standards of restoration according to the height from ground level - the application of zoning such as height district and urban design for preservation Finally, the design of implementation tools must be needed for protection and restoration.