• 한국지진공학회논문집
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• 제25권5호
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• pp.213-221
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• 2021

Many Korean domestic masonry structures constructed since 1970 have been found to be vulnerable to earthquakes because they lack efficient lateral force resistance. Many studies have shown that the brick and mortar suddenly experience brittle fracture and out-of-plane collapse when they reach the inelastic range. This study evaluated the seismic retrofitting of non-reinforced masonry with Hybrid Super Coating (HSC) and Cast, manufactured using glass fiber. Four types of specimen original specimen (BR-OR), one layered HSC (BR-HS-O), two-layered HSC (BR-HS-B), one layered HSC, and Cast (BR-CT-HS-O) were constructed and analyzed using compression, flexural tensile, diagonal compression, and triplet tests. The specimen responses were presented and discussed in load-displacement curves, maximum strength, and crack propagation. The compressive strength of the retrofit specimens slightly increased, while the flexural tensile strength of the retrofit specimens increased significantly. In addition, the HSC and Cast also produced a considerable increase in the ductile response of specimens before failure. Diagonal compression test results showed that HSC delayed brittle cracks between the mortar and bricks and resulted in larger displacement before failure than the original brick. The triplet test results confirmed that the bonding strength of the retrofit specimens also increased. The application of HSC and Cast was found to restrain the occurrence of brittle failure effectively and delayed the collapse of masonry wall structures.

• 대한건축학회논문집:구조계
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• 제36권4호
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• pp.153-161
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• 2020

This study investigates the recycling potential of demolition waste (DW) according to building structure, while considering economic aspects. For that, this study surveyed 1,034 residential buildings to collect reliable information on demolition waste generation rates (DWGRs). This study suggested a method for operational cost calculation for each stage and carried out an inventory analysis. The economic value of recycled DW materials was also calculated. And then, the recycling potential(RP) was calculated by building structures and waste types. RP by building structure was low (27-40%), and RP was found in the order of masonry-block, wooden, RC and concrete-brick. By type of DWs, the RP of aggregates was considerably lower than 7%, and DWs such as wood, plastics, and metals showed more than 100% RP. Considering the results of this study, In order to improve the RP of buildings and DWs, the diversification of products that recycled waste like aggregates (i.e., mortar, concrete, bricks, blocks, tiles) and the development of high value-added products are considered to be the most urgent problems. Based on the above RP results, this study proposed a more advanced method for life cycle assessment of buildings and demolition waste.

• 한국지진공학회논문집
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• 제26권3호
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• pp.137-147
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• 2022

This study investigated the seismic performance of reinforced concrete (RC) wall-slab frames with masonry infills. Four RC wall-slab frames with or without masonry infill were tested under cyclic loading. The RC frames were composed of in-plane and out-of-plane walls and top and bottom slabs. For masonry infill walls, cement bricks were stacked applying mortar paste only at the bed joints, and, at the top, a gap of 50 mm was intentionally left between the masonry wall and top RC slab. Both sides of the masonry walls were finished by applying ordinary or fiber-reinforced mortars. The tests showed that despite the gap on top of the masonry walls, the strength and stiffness of the infilled frames were significantly increased and were different depending on the direction of loading and the finishing mortars. During repeated loading, the masonry walls underwent horizontal and diagonal cracking and corner crushing/spalling, showing a rocking mode inside the RC wall-slab frame. Interestingly, this rocking mode delayed loss of strength, and as a result, the ductility of the infilled frames increased to the same level as the bare frame. The interaction of masonry infill and adjacent RC walls, depending on the direction of loading, was further investigated based on test observations.

• Nuclear Engineering and Technology
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• 제54권1호
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• pp.269-274
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• 2022

An artificial neural network (ANN) that identifies radionuclides from low-count gamma spectra of a NaI scintillator is proposed. The ANN was trained and tested using simulated spectra. 14 target nuclides were considered corresponding to the requisite radionuclide library of a radionuclide identification device mentioned in IEC 62327-2017. The network shows an average identification accuracy of 98.63% on the validation dataset, with the gross counts in each spectrum N_c = 100~10000 and the signal to noise ratio SNR = 0.05-1. Most of the false predictions come from nuclides with low branching ratio and/or similar decay energies. If the N_c>1000 and SNR>0.3, which is defined as the minimum identifiable condition, the averaged identification accuracy is 99.87%. Even when the source and the detector are covered with lead bricks and the response function of the detector thus varies, the ANN which was trained using non-shielding spectra still shows high accuracy as long as the minimum identifiable condition is satisfied. Among all the considered nuclides, only the identification accuracy of ²³⁵U is seriously affected by the shielding. Identification of other nuclides shows high accuracy even the shielding condition is changed, which indicates that the ANN has good generalization performance.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.959-964
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• 2022

Lead is an important material, both for fusion or fission reactors. The cross sections of natural lead should be validated because lead is a main component of lithium-lead modules suggested for fusion power plants and it directly affects the crucial variable, tritium breeding ratio. The presented study discusses a validation of the lead transport libraries by dint of the activation of carefully selected activation samples. The high emission standard ²⁵²Cf neutron source was used as a neutron source for the presented validation experiment. In the irradiation setup, the samples were placed behind 5 and 10 cm of the lead material. Samples were measured using a gamma spectrometry to infer the reaction rate and compared with MCNP6 calculations using ENDF/B-VIII.0 lead cross sections. The experiment used validated IRDFF-II dosimetric reactions to validate lead cross sections, namely ¹⁹⁷Au(n, 2n)¹⁹⁶Au, ⁵⁸Ni(n,p)⁵⁸Co, ⁹³Nb(n, 2n)^92mNb, ¹¹⁵In(n,n')^115mIn, ¹¹⁵In(n,γ)^116mIn, ¹⁹⁷Au(n,γ)¹⁹⁸Au and ⁶³Cu(n,γ)⁶⁴Cu reactions. The threshold reactions agree reasonably with calculations; however, the experimental data suggests a higher thermal neutron flux behind lead bricks. The paper also suggests ²⁵²Cf isotropic source as a valuable tool for validation of some cross-sections important for fusion applications, i.e. reactions on structural materials, e.g. Cu, Pb, etc.

• 한국콘텐츠학회논문지
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• 제22권1호
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• pp.224-239
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• 2022

온라인 판매가 무서운 성장세를 보여주고 있음에도 불구하고, 소비자 채널 전환행동 영역에서 오프라인 밴드왜건이 여전히 많은 주목을 받고 있다. 소비자의 오프라인에서 온라인 소매업자로의 전환행동을 탐색하는 기존연구와 달리, 본 연구는 push-pull-mooring 모델을 기반으로 소비자가 온라인에서 오프라인 채널로 전환하는 이유와 시점에 중점을 두어 살펴본다. 따라서, 본 연구는 구조방정식 모델과 SPSS를 이용하여 설립된 연구가설을 검증하였다. 그 결과는 예상대로 push 요인(지각된 위험과 불만족)과 pull 요인(대안매력과 지각된 주인의식)이 모두 소비자의 온라인에서 오프라인 채널로의 전환의도에 긍정적 영향을 미치는 것으로 나타났다. 또한, push 요인과 전환비용간의 상호작용 및 pull 요인과 주관적 규범간의 상호작용을 제외하고, 모든 push 요인과 mooring 요인(전환비용, 다양성 추구 성향과 주관적 규범)간의 상호작용 및 pull 요인과 mooring 요인간의 상호작용이 검증되었다. 마지막으로 시사점과 한계점을 더불어 제시하였다.

• 한국공간구조학회논문집
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• 제22권3호
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• pp.33-40
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• 2022

Recently, cultural heritages in South Korea gain many interests of restoration and preservation from the government since many of that have been severely damaged during earthquakes. Many previous studies in both terms of experimental and analytical approaches have been done to examine structural behavior and decide appropriate methods of preservation. Being motivated by such researches, this research aims to investigate a religious stone pagoda dated back to the Goryeo Dynasty in Korea. The structure consists of a granite stone foundation and baked bricks, which resembles the shape of traditional pagodas. In order to examine the structural behavior of the pagoda, an analytical model is implemented using ANSYS, a comprehensive engineering simulation platform. For the time history analysis of the pagoda, several earthquake excitations are chosen and input to simulation modeling. Seismic response of the tower such as time domain, natural frequency, modal shapes and peak acceleration measured at each layer are presented and discussed. In addition, the amplification ratio of the tower is calculated from the accelerations of each layer to determine tower stability in accordance with Korean seismic design guide. The determination and evaluation of status and response of the brick tower by simulation analysis play an important role in the preservation of history as well as valuable architectural heritages in South Korea.

• 영어영문학
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• 제56권6호
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• pp.1047-1065
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• 2010

English inversion constructions are not only hard for non-native speakers to learn but also difficult to teach mainly because of their intriguing grammatical and discourse properties. This paper addresses grammatical issues in learning or teaching the so-called 'predicate inversion (PI)' construction (e.g., Equally important in terms of forest depletion is the continuous logging of the forests). In particular, we chart the grammatical (distributional, syntactic, semantic, pragmatic) properties of the PI construction, and argue for adata-driven teaching for English grammar. To depart from the arm-chaired style of grammar teaching (relying on author-made simple sentences), our teaching method introduces a datadriven teaching. With total 25 university students in a grammar-related class, students together have analyzed the British Component of the International Corpus of English (ICE-GB), containing about one million words distributed across a variety of textual categories. We have identified total 290 PI sentences (206 from spoken and 87 from written texts). The preposed syntactic categories of the PI involve five main types: AdvP, PP, VP(ed/ing), NP, AP, and so, all of which function as the complement of the copula. In terms of discourse, we have observed, supporting Birner and Ward's (1998) observation that these preposed phrases represent more familiar information than the postposed subject. The corpus examples gave us the three possible types: The preposed element is discourse-old whereas the postposed one is discourse-new as in Putting wire mesh over a few bricks is a good idea. Both preposed and postposed elements can also be discourse new as in But a fly in the ointment is inflation. These two elements can also be discourse old as in Racing with him on the near-side is Rinus. The dominant occurrence of the PI in the spoken texts also supports the view that the balance (or scene-setting) in information structure is the main trigger for the use of the PI construction. After being exposed to the real data and in-depth syntactic as well as informationstructure analysis of the PI construction, it is proved that the class students have had a farmore clear understanding of the construction in question and have realized that grammar does not mean to live on by itself but tightly interacts with other important grammatical components such as information structure. The study directs us toward both a datadriven and interactive grammar teaching.

• 한국조경학회지
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• 제45권5호
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• pp.87-96
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• 2017

본 연구는 안동 하회마을을 대상으로 1970년대 이후 현재에 이르기까지 담장의 형태적 변화양상을 파악하고자 소재 및 형태, 분포 중심의 변화과정을 4시기로 구분하고, 이에 따른 특성을 살펴본 결과는 다음과 같다. 첫째, 안동 하회마을이 문화재로 지정되기 이전인 1970년대는 마을 중심부의 토담에 기와를 얹은 형태가 주를 이루고 있었으며, 마을 외곽부에서는 토담에 볏짚이나 솔잎 등을 올리거나 담장을 설치하지 않을 경우, 싸리담을 두르기도 하였다. 둘째, 1980년대 문화재 지정 이후에는 초기단계의 문화재 정비가 이루어졌으나, 대부분 퇴락가옥 보수나 기반시설 정비에 중점을 두고 있어 담장에 대해서는 문화재 지정 이전의 분포와 큰 변화가 확인되지 않았다. 셋째, 과거 하회마을의 입지 특성상 담장에 돌을 사용하기 어려운 실정이었으나 1990년대에 들어서면서 토석담으로의 대거 교체가 확인되었으며, 이전시기에 비해 머리부에 기와를 사용한 사례가 증가되었다. 이전시기 주를 이루던 토담의 비중은 감소하였으며, 이러한 양상은 2000년대까지도 지속된 것으로 보인다. 넷째, 현장조사를 통해 오늘날 하회마을의 담장을 살펴본 결과, 마사토에 시멘트, 강회, 자갈 등을 섞은 몸체가 마을 대부분의 담장을 이루고 있었으며 이엉을 얹은 담장과 싸리담의 범위는 마을 외곽부의 일부로 축소되었다. 다섯째, 1970년대부터 현재에 이르기까지 나타나는 하회마을 담장의 변화특성으로 새로운 소재의 사용빈도 증가와 기존 가옥의 담장교체에 따라 머리부에 기와를 얹은 가옥 범위의 확대 등이 도출되었으며, 그 요인은 풍수적 가치 퇴조, 원형 기록에 대한 부족, 건축물 외 시설에 대한 인식 및 전문성 결여, 기타 담장 정비에 대한 마을 주민간의 관계 등으로 확인되었다.

• 헤리티지:역사와 과학
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• 제44권3호
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• pp.112-131
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• 2011

본 고는 경주 사천왕사지 출토 녹유제품의 고고학적 복원을 위한 기초 자료를 마련하고자 SEM-EDX, XRD, TG/DTA를 이용하여 녹유에 대한 화학조성과 용융특성을 연구한 결과이다. 녹유소조상전, 녹유귀면와, 녹유능형전을 분석한 결과 소조상전 2편은 화학조성(PbO 74~81%, $SiO_2$ 14~18%)과 용융온도범위($950{\sim}1070^{\circ}C$)가 유사하였으나, 귀면와 2편과 능형전 1편은 서로 다른 조성과 용융특성을 보였다. 귀면와 SC 003은 소조상전에 비하여 훨씬 낮은 용융온도범위($970^{\circ}C$ 이하)를 보였으며, SC 004는 상대적으로 높은 P의 함량으로 조성상의 차이를 보였다. 능형전은 Pb와 Si, O 이외의 원소가 검출되지 않고, 매우 낮은 용융온도범위($770^{\circ}C$ 이하)를 보여 사천왕사지 녹유제품들과는 다른 특성을 보였으며, 오히려 경주 영묘사지 출토 녹유전 2편과 유사한 특징을 보였다. 이러한 결과는 사천왕사지의 녹유제품들이 모두 같은 원료와 기법으로 제조된 것은 아님을 보여주며, 이에 대해서는 납동위원소비 분석 등의 추가적인 원료 산지 연구가 필요하다. 이상의 결과는 경주 사천왕사지 녹유전의 복원연구를 위한 기초 자료로서 제공될 것이며, 타 유적의 녹유제품 연구에 활용될 것으로 기대된다.