• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2006년도 추계 학술논문 발표대회 논문집
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• pp.147-150
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• 2006

Of the total defects that have occurred recently in the Korean construction market, over 30% are caused by the construction of defective waterproofing, and the phenomenon of air pockets in the waterproofing layer, which is caused by the concrete vapor pressure, is known to be the primary cause of defective waterproofing. Accordingly, in this study the theory about the relationship between water pressure and temperature as well as the damp-proofing volume of concrete and, then, the change of vapor pressure volume was measured and analyzed by making a test sample after spraying a dampness remover and a waterproofing material to a prepared test body. As a result of measuring the water vapor pressure for the surface temperature of the waterproofing layer with the fluid-applied membrane temperature based on about $10^{\circ}C$, which is the average temperature of Seoul, it was found that first, the fluid-applied membrane elevated up to about $40^{\circ}C$, and the water vapor pressure generated from the fluid-applied membrane was about $0.3kgf/cm^2$ when the surface temperature of the waterproofing layer was raised up to about $80^{\circ}C$. Second, when the fluid-applied membrane temperature of the waterproofing layer was raised from $30^{\circ}C\;to\;35^{\circ}C,\;about\;0.1kgf/cm^2$ of water vapor pressure was generated, and when supplying a thermal source to raise the fluid-applied membrane temperature of the waterproofing layer from $35^{\circ}C\;to\;40^{\circ}C$, approximately $0.05kgf/cm^2$ of water vapor pressure was generated.

• Steel and Composite Structures
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• 제18권3호
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• pp.583-601
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• 2015

In the present study, the combined effects of thermal and mechanical loadings on the interlaminar shear stresses of both moderately thin and thick composite laminated beams are numerically analyzed. The finite element modelling of laminated composite beams and analysis of interlaminar stresses are performed using the commercially available software package MSC NASTRAN/PATRAN. The validity of the finite element analysis (FEA) is demonstrated by comparing the experimental test results obtained due to mechanical loadings under the influence of thermal environment with those derived using the present FEA. Various parametric studies are also performed to investigate the effect of thermal loading on interlaminar stresses generated in symmetric, anti-symmetric, asymmetric, unidirectional, cross-ply, and balanced composite laminated beams of different stacking sequences with identical mechanical loadings and various boundary conditions. It is shown that the elevated thermal environment lead to higher interlaminar shear stresses varying with the stacking sequence, length to thickness ratio, ply orientations under identical mechanical loading and boundary conditions of the composite laminated beams. It is realized that the magnitude of the interlaminar stresses along xz plane is always much higher than those of along yz plane irrespective of the ply-orientation, length to thickness ratios and boundary conditions of the composite laminated beams. It is also observed that the effect of thermal environment on the interlaminar shear stresses in carbon-epoxy fiber reinforced composite laminated beams are increasing in the order of symmetric cross-ply laminate, unidirectional laminate, asymmetric cross-ply laminate and anti-symmetric laminate. The interlaminar shear stresses are higher in thinner composite laminated beams compared to that in thicker composite laminated beams under all environmental temperatures irrespective of the laminate stacking sequence, ply-orientation and boundary conditions.

• 헤리티지:역사와 과학
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• 제56권3호
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• pp.46-59
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• 2023

풍납토성에서는 미래마을부지 마-1호 건물지를 비롯하여 백제 지상식 건물지가 여럿 확인되었다. 그러나 기와가 건물지와 직접적으로 관련되어 출토된 건물지는 마-1호 건물지가 유일하다. 마-1호 건물지와 비견되는 마-2호 건물지와 라-1호·2호 건물지 등의 경우에는 적심시설 및 건물 구조로 보건데 지붕에 기와가 올라갔을 가능성이 매우 높은 건물지라 하겠다. 비록 반지하식의 수혈건물지일지라도 내외부 기와 출토상황상 가-30호 수혈건물지나 현대아파트부지 가-5호 주거지 혹은 지상식에 가까운 경당지구 44호 유구처럼 지붕에 전면 즙와가 아닌 부분즙와의 형태로 기와건물이 조성되었을 수도 있다. 지붕에 기와를 사용한 초기 배경에는 여러 이유가 있을 수 있으나 주요한 배경으로는 건물의 위세적 기능이 우선적으로 고려되었을 것으로 여겨진다. 중국과 일본에서 궁전, 사찰, 예제성 건축물(禮制性 建築物) 등 국가적으로 중요한 건물에 기와를 사용하기 시작한 사례로 보아, 백제도 중앙집권화된 시점부터는 적극 사용하였을 것으로 추정된다. 백제 초기 기와건물은 대형화된 건물을 염두에 두고 화재예방과 구조적 안정성을 고려한 결과, 초보적 주거 건축기술에서 고도화된 공공 건축기술로의 변화가 뒤따라오게 된 것으로 여겨진다. 특히 미래 마-1호 건물지는 고대(高臺)나 지하초석과 같은 구조적인 특징상 국내에 유사사례를 찾아보기 힘들고, 오히려 중국과 일본에서 유사 기술을 사용한 중요 건축물을 찾아볼 수 있다. 중국에서는 주로 장안성 등 궁전 주변에 조성된 예제성 건축물에서 유사 건축기술을 발견할 수 있었다. 이를 토대로 보면 마-1호 건물지 등 현재까지 발견된 기와 건물지는 예제성 건축물 성격과 매우 관련 있어 보이며, 라-1호·2호 건물지와 같은 지상식 건물은 국영 창고와 관련된 중요 시설물로 공공시설물과 연계되어 백제 초기의 도성구조와 관련하여 많은 시사점을 주고 있다.

• 상하수도학회지
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• 제37권5호
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• pp.261-269
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• 2023

In light of recent social concerns related to issues such as water supply pipe deterioration leading to problems like leaks and degraded water quality, the significance of maintenance efforts to enhance water source quality and ensure a stable water supply has grown substantially. In this study, scan statistic was applied to analyze water quality complaints and water leakage accidents from 2015 to 2021 to present a reasonable method to identify areas requiring improvement in water management. SaTScan, a spatio-temporal statistical analysis program, and ArcGIS were used for spatial information analysis, and clusters with high relative risk (RR) were determined using the maximum log-likelihood ratio, relative risk, and Monte Carlo hypothesis test for I city, the target area. Specifically, in the case of water quality complaints, the analysis results were compared by distinguishing cases occurring before and after the onset of "red water." The period between 2015 and 2019 revealed that preceding the occurrence of red water, the leak cluster at location L2 posed a significantly higher risk (RR: 2.45) than other regions. As for water quality complaints, cluster C2 exhibited a notably elevated RR (RR: 2.21) and appeared concentrated in areas D and S, respectively. On the other hand, post-red water incidents of water quality complaints were predominantly concentrated in area S. The analysis found that the locations of complaint clusters were similar to those of red water incidents. Of these, cluster C7 exhibited a substantial RR of 4.58, signifying more than a twofold increase compared to pre-incident levels. A kernel density map analysis was performed using GIS to identify priority areas for waterworks management based on the central location of clusters and complaint cluster RR data.

• 디지털융복합연구
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• 제4권1호
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• pp.55-71
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• 2006

The Public Service Charter is one of the administrative reform programs introduced to promote customer oriented administration. It's main purpose is to achieve citizens' confidence in the government by satisfying them with elevated quality of the public services. This study focuses on analyzing current conditions and achievements of the Public Service Charter in the Republic of Korea and proposing it's development plan. Since it was introduced to Korea in 1998, the Public Service Charter has been disseminated and contributed to the spreading of the citizens' understandings of the government's initiatives for customer satisfaction plans. Still, it has several problems as follows; A lot of public servants and citizens lack in understandings of this program. CEOs don't have enough concern in it. Evaluation is not organically connected to performance management. The correction and compensation procedure are not well operated. To solve these problems, the government needs to set up an institutional foundation establishing a legal base, uplifting CFO' concerns, and building a department with full responsibility, and to promote employees and citizens' participation through education and PR. It's also important to enhance post management by efficient evaluation and performance management, substantial correction and compensation procedure.

• Computers and Concrete
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• 제19권5호
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• pp.537-544
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• 2017

The strength and deformational capacity of slender reinforced concrete (RC) columns greatly rely on their slenderness ratios, while an additional secondary moment (i.e., the $P-{\delta}$ effect) can be induced especially when the RC column members are exposed to fire. To evaluate the fire-resisting performances of RC columns, this study proposed an axial force-flexural moment (i.e., P-M) interaction curve model, which can reflect the fire-induced slenderness effects and the nonlinearity of building materials considering the level of stress and the magnitude of temperature. The P-M interaction model proposed in this study was verified in detail by comparing with the fire test results of RC column specimens reported in literature. The verification results showed that the proposed model can properly evaluate the fire-resisting performances of RC column members.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.455-460
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• 2004

The Fuel cell Rubber tired Train (FRT), which is now getting the attention as the next generation vehicle with its environment-friendliness, is the transportation for smooth connections of city traffic. It is the revival of the surface-car system with its revaluation of the function and technological development. Accordingly, fixed time operation and high speed driving became possible. FRT is operated together with other vehicles on the regular drive way. While this vehicle can solve the problem of traffic congestion in the urban area, it also can be cost-effective when it is compared to the cost of subway construction. It is also designed to minimize the underground or elevated traffic lane, to introduce the new construction technology, to reduce a term of works, and to cut down the operation cost by unmanned automatic driving system. Furthermore, it is considered as the alternative measure of other transportation due to its potential for the ecological way of speed improvement and the accessability to the disabled, elderly and children by developing the vehicle with folding steps or by building the high boarding platforms. In this research, I concentrated on the user oriented interior design of the FRT to make it passenger-friendly and safe in order to maximize the utilization of the vehicle so that all users including wheelchaired, user with baby carriage, elderly and children can conveniently use this vehicle.

• 한국전자파학회지:전자파기술
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• 제24권2호
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• pp.51-57
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• 2013

The current expanding mobile markets incessantly demands small form factor, low power consumption and high aggregate throughput for silicon-level integration such as memory to logic system. One of emerging solution for meeting this high market demand is 3D through silicon stacking (TSS) technology. Main challenges to bring 3D TSS technology to the volume production level are establishing a cost effective supply chain and building a reliable manufacturing processes. In addition, this technology inherently help increase number of IOs and shorten interconnect length. With those benefits, however, potential signal and power integrity risks are also elevated; increase in PDN inductance, channel loss on substrate, crosstalk and parasitic capacitance. This paper will report recent progress of wide IO memory to high count TSV logic device assembly development work. 28 nm node TSV test vehicles were fabricated by the foundry and assembled. Successful integration of memory wide IO chip with less than a millimeter package thickness form factor was achieved. For this successful integration, we discussed potential signal and power integrity challenges. This report demonstrated functional wide IO memory to 28 nm logic device assembly using 3D package architecture with such a thin form factor.

• 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.

• 국제초고층학회논문집
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• 제7권4호
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• pp.343-362
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• 2018

A simplified spring connection modelling approach for steel flush endplate beam-to-column connections in fire has been developed to enable realistic behaviour of connections to be incorporated into full-scale frame analyses at elevated temperature. Due to its simplicity and reliability, the proposed approach permits full-scale high-temperature frame analysis to be conducted without high computational cost. The proposed simplified spring connection modelling approach has been used to investigate the influence of connection ductility (both axial and rotational) on frame behaviour in fire. 2D steel and 3D composite frames with a range of beam spans were modelled to aid the understanding of the differences in frame response in fire where the beam-to-column connections have different axial and rotational ductility assumptions. The modelling results highlight that adopting the conventional rigid or pinned connection assumptions does not permit the axial forces acting on the connections to be accurately predicted, since the axial ductility of the connection is completely neglected when the rotational ductility is either fully restrained or free. By accounting for realistic axial and rotational ductilities of beam-to-column connections, the frame response in fire can be predicted more accurately, which is advantageous in performance-based structural fire engineering design.