• Steel and Composite Structures
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• 제51권2호
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• pp.173-183
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• 2024

This study investigates a new seismic retrofit system that utilizes rotational friction dampers and axial springs. The retrofit system involves a steel frame with rotational friction dampers (RFD) at beam-column joints and linear springs at the corners, providing energy dissipation and self-centering capabilities to existing structures. The axial spring acts as a self-centering mechanism that eliminates residual deformations, while the friction damper mitigates seismic damage. To evaluate the seismic performance of the proposed retrofit system, a series of cyclic loading tests were carried out on a steel beam-column subassembly equipped with the proposed devices. An analytical model was then developed to validate the experimental results. A performance point ratio (PPR) was presented to optimize the design parameters of the retrofit system, and a performance-based seismic design strategy was developed based on the PPR. The retrofit system's effectiveness and the presented performance-based design approach were evaluated through case study models, and the analysis results demonstrated that the developed retrofit system and the performance-based design procedure were effective in retrofitting structures for multi-level design objectives.

• 한국ITS학회 논문지
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• 제15권5호
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• pp.20-28
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• 2016

유비쿼터스 도시(ubiquitous city, U-City)는 도시건설에 정보통신기술(ICT)이 접목되어 시민 삶의 질을 제고하고 도시를 효율적으로 관리하는 스마트한 도시의 개념을 내포한다. 유비쿼터스 도시의 건설 등에 관한 법률은 U-City의 구성요소로 도시통합운영센터, 지능화시설, U-City 기반시설 등을 제시하나 구체적 기준이 부재한 상태이다. 이로 인해 지자체들이 자의적 판단과 현실적 제약으로 U-City를 차별적으로 구축하고 있어 지자체 U-City의 질적 향상 및 품질 제고를 위한 노력이 필요한 시기이다. 지난 1-2차 연구단계에서는 U-City의 구성요소인 유비쿼터스 계획, 기술, 기반시설, 서비스 수준진단목표로서 안정성, 연결성, 목적부합성, 발전성을 기반으로 전반적 평가항목들을 검토하였다. 이 연구는 3차 단계로 지역현실에 맞게 지자체의 U-City 수준을 진단하기 위해 갱신 및 시범 적용이 가능한 실질적이고 구체적인 평가지표를 단계별로 소개한다. 연구결과를 통하여 U-City의 스마트화를 위한 지속적인 발전 및 고도화를 촉진하기 위해 자생적인 지역단위의 U-City로 정착할 수 있고 U-City의 재활성화 촉진에 기여할 것으로 기대된다.

• Steel and Composite Structures
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• 제47권2호
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• pp.167-184
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• 2023

In this study, a new recentering friction device (RFD) to retrofit steel moment frame structures is introduced. The device provides both self-centering and energy dissipation capabilities for the retrofitted structure. A hybrid performance-based seismic design procedure considering multiple limit states is proposed for designing the device and the retrofitted structure. The design of the RFD is achieved by modifying the conventional performance-based seismic design (PBSD) procedure using computational intelligence techniques, namely, genetic algorithm (GA) and artificial neural network (ANN). Numerous nonlinear time-history response analyses (NLTHAs) are conducted on multi-degree of freedom (MDOF) and single-degree of freedom (SDOF) systems to train and validate the ANN to achieve high prediction accuracy. The proposed procedure and the new RFD are assessed using 2D and 3D models globally and locally. Globally, the effectiveness of the proposed device is assessed by conducting NLTHAs to check the maximum inter-story drift ratio (MIDR). Seismic fragilities of the retrofitted models are investigated by constructing fragility curves of the models for different limit states. After that, seismic life cycle cost (LCC) is estimated for the models with and without the retrofit. Locally, the stress concentration at the contact point of the RFD and the existing steel frame is checked being within acceptable limits using finite element modeling (FEM). The RFD showed its effectiveness in minimizing MIDR and eliminating residual drift for low to mid-rise steel frames models tested. GA and ANN proved to be crucial integrated parts in the modified PBSD to achieve the required seismic performance at different limit states with reasonable computational cost. ANN showed a very high prediction accuracy for transformation between MDOF and SDOF systems. Also, the proposed retrofit showed its efficiency in enhancing the seismic fragility and reducing the LCC significantly compared to the un-retrofitted models.

• 한국안전학회지
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• 제25권6호
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• pp.123-127
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• 2010

A fire disaster is very serious in the closing space like subway station. In this study, the simulation on fire diffusion is performed to get the temperature history curve, which is used for the fire resisting structural analysis. Most of subway stations are built by the reinforced concrete structure, but recently steel structures are selected for the larger space or beauty. Steel structures relatively have more weaknesses against fire, so it is necessary to develop the method for evaluating fire-resisting capacity in this kind of structures. The developed method is applied to the subway station in Daegu city. It shows that the developed method can be used to simulate the fire disaster and to get the temperature history curve and evaluate the safety of steel structures against the fire.

• Structural Engineering and Mechanics
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• 제16권5호
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• pp.581-595
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• 2003

Since the conventional direct approaches are hard to be applied for damage diagnosis of complex large-scale structures, a two-step approach for diagnosing the joint damage of framed structures is presented in this paper by using artificial neural networks. The first step is to judge the damaged areas of a structure, which is divided into several sub-areas, using probabilistic neural networks with natural Frequencies Shift Ratio inputs. The next step is to diagnose the exact damage locations and extents by using the Radial Basis Function (RBF) neural network with the second Element End Strain Mode of the damaged sub-area input. The results of numerical simulation show that the proposed approach could diagnose the joint damage of framed structures induced by earthquake action effectively and has reliable anti-jamming abilities.

• 한국환경과학회지
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• 제24권3호
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• pp.303-316
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• 2015

The relationship between urban spatial structures and GHG-AP integrated emissions was investigated by statistically analyzing those from 25 administrative districts of Seoul. Urban spatial structures, of which data were obtained from Seoul statistics yearbook, were classified into five categories of city development, residence, environment, traffic and economy. They were further classified into 10 components of local area, population, number of households, residential area, forest area, park area, registered vehicles, road area, number of businesses and total local taxes. GHG-AP integrated emissions were estimated based on IPCC(intergovernmental panel on climate change) 2006 guidelines, guideline for government greenhouse inventories, EPA AP-42(compilation of air pollutant emission factors) and preliminary studies. The result of statistical analysis indicated that GHG-AP integrated emissions were significantly correlated with urban spatial structures. The correlation analysis results showed that registered vehicles for GHG (r=0.803, p<0.01), forest area for AP (r=0.996, p<0.01), and park area for AP (r=0.889, p<0.01) were highly significant. From the factor analysis, three groups such as city and traffic categories, economy category and environment category were identified to be the governing factors controlling GHG-AP emissions. The multiple regression analysis also represented that the most influencing factors on GHG-AP emissions were categories of traffic and environment. 25 administrative districts of Seoul were clustered into six groups, of which each has similar characteristics of urban spatial structures and GHG-AP integrated emissions.

• 한국엔터테인먼트산업학회논문지
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• 제14권3호
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• pp.181-190
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• 2020

2017년에 개봉한 영화 <아수라>는 김성수 감독과 정우성, 황정민, 주지훈, 곽도원, 정만식 배우의 조합만으로도 개봉 전부터 큰 관심을 이끌어냈던 영화이다. 범죄영화 혹은 느와르영화로서의 장르성에 충실했지만 영웅 원형의 캐릭터적 전복성과 영웅 서사 구조의 변주로 인해 평단과 관객의 다양한 해석을 이끌어내며 다층적 이슈를 만들어낸 영화이기도하다. 본 논문은 크리스토퍼 보글러의 '영웅의 여행'에 입각하여 영화 <아수라>의 영웅 서사 구조를 분석하고, 보글러가 말하는 서사 구조의 보편성과 전형성이 본 영화에 어떻게 적용되는지 살펴보고자한다. 이를 통해 영화 <아수라>의 서사구조가 지닌 비전형적 특징을 도출한 후 이러한 변주가 영웅의 서사구조를 어떻게 새롭게 변화시켰는지 그리고 관객의 기대일치는 어떻게 변주되었는지를 살펴보고, 새로운 서사적 대안으로서 어떠한 가능성으로 활용될 수 있는지에 대해 고찰해 보고자 한다.

• 헤리티지:역사와 과학
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• 제45권3호
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• pp.28-59
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• 2012

원(元) 상도(上都) 유적은 유목생활의 특색을 지닌 초원의 도성(都城)으로 역대로 많은 여행가와 역사학자, 고고학자들의 주목을 받아왔다. 원조(元朝)부터 몇몇 유럽의 저명한 여행가들은 원 상도를 생동감 있게 묘사하였고, 근대에는 수많은 외국 여행가와 역사학자들이 원 상도를 현지답사하고 여행기와 연구보고서를 발표하였다. 20세기에 들어와서는 주로 중국, 일본의 역사학자와 고고학자들이 원 상도에 대해 비교적 전면적인 역사 고증과 고고학 조사를 진행하였고 아울러 논저와 고고학 조사보고서를 발표하였다. 1990년대에 들어와서 보다 더 전면적이고 과학적인 고고학 조사와 실측 및 발굴 작업이 진행되었다. 본문은 상술한 여행가, 지리학자, 고고학자들의 원상도에 대한 조사와 기록을 회고하면서 20세기 말에 이루어진 원상도의 조사와 발굴 자료를 통해 원상도의 건축유적에 대한 기초적인 토론을 진행하고자 한다.

• 한국방재학회 논문집
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• 제5권4호
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• pp.71-78
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• 2005

우리나라 도로교설계기준(2005)에서 규정하고 있는 내진설계의 기본개념은 인명피해를 최소화하고 설계지진은 구조물 수명동안 발생할 확률이 거의 없다는 것이다. 구조물 내진설계의 가장 상위개념이며 합리적인 내진대책은 인명피해를 최소화해야하며 경제성이 있어야 한다. 결과적으로 최우선의 목표를 만족시키기 위해서는 개별적인 구조물 중심이 아닌 도시 전체를 대상으로 한 거시적인 평가방안이 필요하다. 도시지역에 대한 피해상황은 기타지역과 다른 양상을 나타내며, 도시가 거대해질수록 구조물의 파손에 의한 손실보다는 오히려 이에 수반되는 부가적인 손실이 월등히 클 것이다. 그리고 거시적인 지진재해 평가방법은 인구와 구조물이 밀집되고, 정치 경제활동 등의 중심이 되는 오래된 도시일수록 효과가 탁월할 것이다. 본 연구는 지진재해위험을 합리적으로 예측할 수 있는 지진재해위험지수를 개발하고, 서울특별시를 6개 구역으로 분할하여 상대적인 지진재해위험을 평가하였다.

• Geomechanics and Engineering
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• 제16권4호
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• pp.435-448
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• 2018

In order to make reliable earthquake-resistant design of civil engineering structures, one of the most important considerations in a region with high seismicity is to pay attention to the local soil condition of regions. It is aimed in the current study at specifying dynamic soil characteristics of Kirikkale city center conducting the 1-D equivalent linear and non-linear site response analyses. Due to high vulnerability and seismicity of the city center of Kirikkale surrounded by active many faults, such as the North Anatolian Fault (NAF), the city of Kirikkale is classified as highly earthquake-prone city. The first effort to determine critical site response parameter is to perform the seismic hazard analyses of the region through the earthquake record catalogues. The moment magnitude of the city center is obtained as $M_w=7.0$ according to the recorded probability of exceedance of 10% in the last 50 years. Using the data from site tests, the 1-D equivalent linear (EL) and nonlinear site response analyses (NL) are performed with respect to the shear modulus reduction and damping ratio models proposed in literature. The important engineering parameters of the amplification ratio, predominant site period, peak ground acceleration (PGA) and spectral acceleration values are predicted. Except for the periods between the period of T=0.2-1.0 s, the results from the NL are obtained to be similar to the EL results. Lower spectral acceleration values are estimated in the locations of the city where the higher amplification ratio is attained or vice-versa. Construction of high-rise buildings with modal periods higher than T=1.0 s are obtained to be suitable for the city of Kirikkale. The buildings at the city center are recommended to be assessed with street survey rapid structural evaluation methods so as to mitigate seismic damages. The obtained contour maps in this study are estimated to be effective for visually characterizing the city in terms of the considered parameters.