• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.10-19
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• 2022

Irregularity in structural shape is a ubiquitous phenomenon. Structural hazards evoked from irregularity need to be checked against extreme lateral loadings. Structures containing four distinct types of irregularities in terms of continuity and discontinuity in upper half-length and all story levels along with O-shape are investigated. The structures were analyzed numerically and different seismic responses such as displacements, bending moment, axial forces, torsions, story drift, etc. were scrutinized. The seismic and wind load analysis was conducted for ACI 318-11 conditions. Results show that buildings having discontinuous beams on the upper half exhibit better resilience. It is also concluded that O-shaped building structures provide better resistance to overturning, making this shape relatively safe.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2015.11a
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• pp.155-159
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• 2015

본 연구는 도시방재력 향상을 위한 학교시설의 유지관리에 관한 연구로 도심지에 있는 학교시설의 필요시 방재기능으로 활용 할 수 있도록 방재기능을 외보공간측면, 내부공간측면으로 구분하교 세부 사항을 설정하였다. 그리고 지속적으로 사용 할 수 있도록 유지관리 측면을 안전, 건물, 균열, 누수, 기계, 설비(급배기, 급배수, 난방) 등으로 구분하였다. 또한 유지관리 주기는 상시관리, 2~3년 주기, 5년 주기로 설정하여 방재기능을 유지관리 방안을 정리하였다.

• Journal of Bio-Environment Control
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• v.14 no.2
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• pp.119-127
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• 2005

This study was carried out to investigate the effect of magnesium concentrations in fertilizer solution on growth and cut flower quality of chrysanthemum 'Biarritz'. The nutrient concentrations in plant tissue and soil solution of root media were also determined. Magnesium deficiency appeared on older leaves with interveinal yellow-green chlorosis. Marginal chlorosis and necrosis also developed on some of older leaves. Elevation of Mg concentration in fertilizer solution increased cut flower weight at harvesting stage resulting in the 8.84g in 1.5mM treatment. Dry weight of whole above ground plant tissue increased as Mg concentrations in fertilizer solution were elevated within the range from 0 to 15mM, but that of 20mM decreased compared to 15mM treatment. The dry weight of 0.5, 1.0 and 1.5mM treatments were 8.42, 8.75 and 8.848 and tissue Mg contents of those based on the youngest fully expanded leaves at harvesting stage were 0.34, 0.53 and $0.71\%$, respectively. Based on dry weight and tissue Mg contents, Mg fertilization to maintain tissue contents higher than $0.64\%$ is necessary to ensure flower quality and yield. By considering the concentration in 15mM treatment, Mg concentration in soil solution of root media should be higher than $3.68mg{\cdot}L^{-1}$ at harvesting stage.

• Journal of the Korea Institute of Building Construction
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• v.10 no.2
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• pp.41-50
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• 2010

This study presented a model that can enable a reliability analysis for the repair and replacement cycle of a building by using background repair and replacement data and expert opinion as foundation data and applying Monte Carlo Simulation. The presented model offers the time of the repair and replacement of building elements for the period of a year, and supports the prediction of repair and replacement and expenses demand in advance while planning the maintenance of a building. In addition, the model will significantly reduce the risks to the building owner with regard to maintenance decisions. In addition, when a person in charge of the maintenance of large-scale building assets is having difficulties making decisions regarding the repair and replacement of existing building elements due to a lack of background data to support a long-term policy on the repair and replacement requirements, an engineering solution that can ensure the adequacy of this is provided. In summary, it can be largely divided into three study results. First, a method of estimating the repair and replacement cycle that can deal with the development of a construction system was developed. Second, a probabilistic methodology that can quantify the risk of the repair and replacement cycle was proposed. Third, the proposed model can be used as a means of supporting designer and constructor in making decisions for the life cycle plan of a building during a construction project.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.2
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• pp.9-20
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• 2014

Steel intermediate moment frames (IMFs) have been generally used as seismic load resisting systems (SLRSs) of a building to provide resistances against strong ground shaking. However, most of low and mid-rise steel buildings in Korea were constructed during pre-seismic code era or before the introduction of well-organized current seismic codes. It has been recognized that the seismic performance of these steel IMFs is still questionable. In order to respond to such a question, this study quantitatively investigates the seismic capacities of steel IMFs. Prototype models are built according to the number of stories, the levels of elastic seismic design base shear and the ductilities of structural components. Also, the other prototype models employing hysteretic energy dissipating devices (HEDDs) are considered. The collapse mechanism and the seismic performance of the prototype models are then described based on the results obtained from nonlinear-static and incremental-dynamic analyses. The seismic performance of the prototype models is assessed from collapse margin ratio (CMR) and collapse probability. From the assessment, the prototype model representing new steel IMFs has enough seismic capacities while, the prototype models representing existing steel IMFs provide higher collapse probabilities. From the analytic results of the prototype models retrofitted with HEDDs, the HEDDs enhance the seismic performance and collapse capacity of the existing steel IMFs. This is due to the energy dissipating capacity of the HEDDs and the redistribution of plastic hinges.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.4
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• pp.671-679
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• 1999

건물의 진동에너지 소산능력을 향상하기 위하여 점탄성감쇠를 설치하게 되면 이른바 비비례 감쇠시스템이 되어 구조물은 복소수형태의 고유모드와 고유치를 가진다. 복소모드중첩법은 이러한 복소모드를 이용하여 중첩함으로써 비비례 감쇠시스템 구조물의 정확한 동적 거동을 얻을 수 있는 방법이다. 그러나 건물이 고층화되면 많은 자유도로 인하여 고유치해석 및 모드중첩과정에서 많은 시간과 노력이 필요하게 된다. 본 논문에서는 효율적인 구조물의 모형화를 위하여 강막가정과 행렬응축기법을 적용하였다. 또한 몇 개의 주요 모드만을 선택하여 중첩하는 방법에 대하여 연구하였으며 구조물의 진동에 영향을 주는 모드의 선택을 위한 복소모드 응답참여계수를 제안하였다. 제안된 해석방법의 정확성과 효율성을 검토하기 위하여 예제 구조물을 대상으로 해석한 결과, 응답의 정확성을 유지하면서 해석에 필요한 시간을 대폭 절감할 수 있었다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.601-604
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• 2010

기하형상이나 엔지니어링에 관한 정보를 3차원 모델기반으로 다루는 BIM기술은 기존의 2차원 도면작업들에 비해 업무의 효율성이나 신속성, 비용측면 등에서 많은 이점을 제공할 수 있어 건축계획 및 설계, 엔지니어링, 시공, 유지관리, 에너지분석 등 건설산업의 전 분야에 활용되고 있다. 본 논문은 BIM용 프로그램들간에 정보교환을 위해 사용되는 건물의 국제표준 정보모델인 IFC 파일로부터 구조해석을 위한 건물형상모델을 자동으로 구축하기 위한 방법을 제시하고, 실제 구현한 프로그램으로 적용사례를 보여준다.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1693-1695
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• 2005

최근 공공건물에 신재생에너지 적용이 의무화되었고, 기후변화협약의 발효로 이산화탄소배출 절감에 대한 관심이 매우 높다. 가장 효율이 높은 냉난방 시스템인 지열히트펌프를 대표적인 신재생에너지인 태양광발전을 이용하여 구동하여 건물을 냉난방을 수행하도록 적용되었다. 야간 또는 태양에너지 밀도가 낮은 날을 위하여 축열과 축냉을 할 수 있는 수축열시스템과 연계하여 적용되었다. 지열히트펌프는 도심지역의 열섬현상 해소에 기여할 수 있으며, 외기 온도의 변화에 관계없이 쾌적한 실내환경을 유지할 수 있으며 향후에 그린 빌딩인증등을 위해 에너지 절약과 신재생에너지 사용량을 높일 수 있는 방안으로 판단된다. 이를 적용한 설치 사례에 대한 사양과 운전 조건이 제시된다.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.27 no.6
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• pp.533-540
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• 1998

최근에 국내외 에너지 이용 효율성 증대 문제, CFCs등으로 인한 오존층 파괴문제, $CO_2$ 등으로 인한 지구온난화 문제, 실내공기질(IAQ)과 관련된 건물 환기량 증대요구로 인한 건물용 공조시스템(HVAC)의 설계변경 문제 등으로 인해 다양한 종류의 대체 냉방기기가 연구되어 오고 있다. 현재 미국에서는 ASHRAE Standard 62-1989에 의해 실내거주자의 필요한 IAQ와 쾌적함을 유지하기 위해 환기량을 기존의 경우보다 약 3배 이상이 되도록 권장하고 있고 또한 대다수의 미국 주 정부에서 건물설계에 관련된 조례로 ASHRAE Standard 62-1989를 적용하고 있다. 따라서 빌딩공조 설비관계자들은 늘어난 환기 요구량에 따라 잠열냉방용량이 크게 증대되므로 이를 처리하기 위한 새로운 냉방공조기기 시스템기술에 대해 관심이 증대하고 있다. 이에 따라 건조제를 x이용한 냉방 및 제습 시스템이 대체 냉방시스템 또는 기존의 냉방 시스템과 더불어 잠열부하를 처리하는 복합 시스템으로 최근에 다시 상당한 주목을 받고 있다.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.2
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• pp.121-128
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• 2003

This study was conducted to investigate the effect of tall type mixtures and tall+short type mixtures on dry matter yield, botanical composition and quality. The experimental design includes two mixture types: Tall type mixtures(TM); orchardgrass(Potomac) 40+tall fescue(Fawn) 20+Festulolium braunii (Paulita) 10+perennial ryegrass(Reveille) 10+timothy(Climax) 10+red clover(Kenland) 5+alfalfa(Vernal) 5%) and tall+short type mixtures(TSM); orchardgrass(Potomac) 40+tall fescue(Fawn) 20+Kentucky bluegrass(Newport, turf type) 10+redtop(Barricuda, turf type) 10+perennial ryegrass(Palmer III, turf type) 10+red fescue(Flyer II, turf type) 5+white clover(Regal) 5%. The dry matter(DM) yield was higher obtained in TSM than that of TM, but there was no significant difference between TM and TSM. In the chemical composition, there was no significant difference between TM and TSM, but the content of cellulose, lignin were higher in TM than those in TSM(p<0.05). Also, the content of acid detergent fiber which affected dry matter digestibility was higher in TM than that of TSM. The crude protein dry matter yield was not observed significant difference between TM and TSM, but digestible dry matter(DDM) yield was higher in TSM than that of TM. In botanical composition, tall fescue, alfalfa and orchardgrass were highly maintained in TM but white clover, tall fescue and orchardgrass were highly, and redtop, red fescue were continuously maintained in TSM. In this experiment, DM yields and quality of two mixture types were no difference. However, the tall+short type mixtures(TSM) were more effective in enhancing the dry matter digestibility and DDM yield, and in maintaining the various botanical composition.