• Structural Engineering and Mechanics
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• 제52권6호
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• pp.1085-1098
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• 2014

Plastic mechanism analysis of structures subjected to large deformation has long been used in order to determine collapse mechanisms of steel structures, and the energy absorbed in plastic deformation during such collapses. In this paper the technique is applied to vehicle roof structures that undergo large plastic deformation as a result of rollover crashes. The components of such roof structures are typically steel spot-welded hat-type sections. Ten different deformation mechanisms are defined from investigations of real-world rollover crashes, and an analytical technique to determine the plastic collapse load and energy absorption of such mechanisms is determined. The procedure is presented in a generic manner, such that it may be applied to any vehicle structure undergoing a rollover induced collapse. The procedure is applied to an exemplar vehicle, in order to demonstrate its application in determining the energy absorbed in the deformation of the identified collapse mechanisms. The procedure will be useful to forensic crash reconstructionists, in order to accurately determine the initial travel velocity of a vehicle that has undergone a rollover and for which the post-crash vehicle deformation is known. It may also be used to perform analytical studies of the collapse resistance of vehicle roof structures for optimisation purposes, which is also demonstrated with an analysis of the effect of varying the geometric and material properties of the roof structure components of the exemplar vehicle.

• Structural Engineering and Mechanics
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• 제47권3호
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• pp.401-419
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• 2013

In this study, the efficiency of adaptive neuro-fuzzy inference system (ANFIS) and genetic expression programming (GEP) in predicting the effects of infill walls on base reactions and roof drift of reinforced concrete frames were investigated. Current standards generally consider weight and fundamental period of structures in predicting base reactions and roof drift of structures by neglecting numbers of floors, bays, shear walls and infilled bays. Number of stories, number of bays in x and y directions, ratio of shear wall areas to the floor area, ratio of bays with infilled walls to total number bays and existence of open story were selected as parameters in GEP and ANFIS modeling. GEP and ANFIS have been widely used as alternative approaches to model complex systems. The effects of these parameters on base reactions and roof drift of RC frames were studied using 3D finite element method on 216 building models. Results obtained from 3D FEM models were used to in training and testing ANFIS and GEP models. In ANFIS and GEP models, number of floors, number of bays, ratio of shear walls and ratio of infilled bays were selected as input parameters, and base reactions and roof drifts were selected as output parameters. Results showed that the ANFIS and GEP models are capable of accurately predicting the base reactions and roof drifts of RC frames used in the training and testing phase of the study. The GEP model results better prediction compared to ANFIS model.

• 한국주거학회논문집
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• 제18권1호
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• pp.113-122
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• 2007

Houses in Jeju city are divided into separated types and combination types of household affairs space. Other special types are separated-kitchen type. Separated household affairs space type is mostly built. Separated household affairs space type were sitting room + Gopang separate type and separate sitting room type. Combination household affairs space type made from sitting room, kitchen, Gopang and Chabang(Dinning room) put together as space differentiation, also into classes sitting room + kitchen + Gopang + Chabang type, sitting room + kitchen + Chabang type, sitting room + kitchen + Gopang, sitting room + kitchen type by combination household cares space type. Separated-kitchen type was one of the special type from separated-kitchen type of traditional housing, and type with continuous. Houses in Jeju city were 3 kan type and 4 kan type. 4kan type was mostly built. ㅡ shape is kept as plan shaped of straight shape, and roof shape is showed as ㅡ shape gathering roof. ㅡ shape + part projection type talls part projecting type as happened in Gopang, and Chabang. Roof is gathering roof, and when it is showed ㄱ shape by Gopang, Chabang, and kitchen are projected. ㅡ shape + total projection shape is one of the room become totally projected by Gopang and Chabang, can be happen with small room or kitchen, and roof as gathering roof shaped with ㅡ shape, ㄱ shape, ㄷ shape, unsystematic ㄹ shape, and various shapes.

• Wind and Structures
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• 제19권2호
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• pp.113-144
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• 2014

Separation bubble and conical vortices on a large-span flat roof were observed in this study through the use of flow visualization. The results indicated that separation bubble occurred when the flow was normal to the leading edge of the flat roof. Conical vortices that occur under the cornering flow were observed near the leading edge, and their appearance was influenced by the wind angle. When the wind changed from along the diagonal to deviating from the diagonal of the roof, the conical vortex close to the approaching flow changed from circular to be more oblong shaped. Based on the measured velocities in the conical vortices by flow visualization, a proposed two-dimensional vortex model was improved and validated by simplifying the velocity profile between the vortex and the potential flow region. Through measured velocities and parameters of vortices, the intensities of conical vortices and separation bubble on a large-span flat roof under different wind directions were provided. The quasi-steady theory was corrected by including the effect of vortices. With this improved two-dimensional vortex model and the corrected quasi-steady theory, the mean and peak suction beneath the cores of the conical vortices and separation bubble can be predicted, and these were verified by measured pressures on a larger-scale model of the flat roof.

• 환경영향평가
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• 제19권6호
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• pp.591-605
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• 2010

Cool roofs are currently being emerged as one of important mechanism to save energy in relation to the building. This paper reviews worldwide experiences (USA, Japan and EU etc) for the potential benefits cool roofs offer in relation to building energy saving for comparison purposes. It is confirmed that there is a significant potential to the energy saving by introducing the cool roof in a Korean climate because of similarity in terms of HDD (Heating Degree Day) and CDD (Cooling Degree Day) as those countries reviewed. Such a comparative study highlights that the type of measurements performed and the quantitative parameters reported from the countries should be standardized in Korean context in order to implement further comparable experiments for scientifically sound investigations. It is anticipated that this research output could be used as a valuable reference in implementing a Nation-wide cool roofing strategy in the central and local governments since a suitable technical, more objective direction has been proposed based on the measured, fully quantitative performance of the involved components of a cool roof system in the global context. From this critical review, a very important step has been made concerning the practicality of cool roof in Korean context. Ultimately, the suggestion in this paper will greatly contribute to opening new possibilities for introducing cool roof in this country, proposed as an initial aim of this paper.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 춘계학술논문 발표대회
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• pp.13-17
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• 2007

The green roof industry have been developed with Europe, North America, Japan. At the same time, being recognized the important of green roofs in domestic industry and we just start to develop the relative technology as analyzing the future direction of advanced technology. Recently, local self-government including Seoul support the system for green roof which provide 50% of working expenses form of Matching Fund by Seed Money. As years go by, the number of build up the green roof has gradually increased to be proved. At this result caused by management of system in government, unstructured construction system, low development of support technology. In this study as analyzing the present of technical development, supporting by law and system for the advanced waterproofing and root penetration resistance technology, we suggest the development direction of it to be compared with application advanced technology and we could strengthen the international competitiveness to be industrialized the green roof considering system, technology, human infrastructure.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2001년도 학술대회지
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• pp.228-231
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• 2001

부산종합운동장 주경기장 지붕구조는 케이블현수구조로 그 시공은 VSL 리프팅시스템을 사용한 인양공법을 채택하여 이루어 졌다. 본 지붕구조물의 시공은 크게 5단계 공정으로 이루어 졌고, 상기 공정 중 인양작업은 상부케이블과 하부케이블로 나누어 1차 인양작업과 2차 인양작업으로 이루어 졌다. 본 지붕구조물의 경우 각 케이블의 정착단은 조정이 불가능한 개방소켓으로 되어 있어 설계시 각 케이블의 길이 계산이 잘못될 경우에는 케이블이 구조부재로써 소정의 성능을 유지하기 위해 필요한 인장응력의 도입이 불가능하게 된다. 그러나, 구조물의 인양이 완료된 상태에서 계측된 각 케이블의 장력에 의하면 평균 $4\%$정도의 정확도를 보이고 있어 설계뿐만 아니라 지붕구조와 관련된 모든 공정의 시공이 치밀하게 이루어 졌음을 보여 주고 있다.

• 대한두개안면성형외과학회지
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• 제19권3호
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• pp.214-217
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• 2018

Skeletal cavernous hemangiomas are rare, benign tumors that may involve the supraorbital rim and orbital roof. However, such involvement is extremely rare. We report a case of skeletal cavernous hemangioma of the frontal bone involving the orbital roof and rim. En bloc excision and reconstruction, using a calvarial bone graft for the orbital roof and rim defect, was performed. It is important not only to perform total excision of skeletal cavernous hemangiomas, but to properly reconstruct the defects after the total excision since several complications can arise from an orbital roof and rim defect.

• 한국가스학회지
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• 제6권1호
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• pp.32-37
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• 2002

천연가스는 청정 무공해 에너지라는 장점으로 소비량이 매년 크게 증가하고 있는 주요 에너지원이다 천연가스 수요의 증가에 따른 LNG 저장 시설의 확충이 요구되고 있어, 한국가스공사에서는 LNG 저장탱크 설계 기술을 개발하고 있다. 본 논문에서는 유한요소법을 이용하여 LNG 저장탱크의 Roof를 설계에 대하여 연구하였으며, 설계 및 평가에 적용된 하중 조건과 안전 코드는 BS7777 코드에 따라 연구하였다.

• Geomechanics and Engineering
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• 제19권3호
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• pp.269-282
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• 2019

Due to top-coal and immediate roof as cushion layer connecting with support and overlying strata, it can make significant influence on strata behaviors in fully mechanical top-coal caving working face (TCCWF). Taking Qingdong 828 working face as engineering background, $FLAC^{3D}$ and $UDEC^{2D}$ were adopted to explore the influence of top-coal thickness (TCT), immediate roof thickness (IRT), top-coal elastic modulus (TCEM) and immediate roof elastic modulus (IREM) on the vertical stress and vertical subsidence of roof, caving distance, and support resistance. The results show that the maximum roof subsidence increases with the increase of TCT and IRT as well as the decrease of TCEM and IREM, which is totally opposite to vertical stress in roof-control distance. Moreover, although the increase of TCEM and IREM leading to the increase of peak value of abutment pressure, the position and distribution range have no significant change. Under the condition of initial weighting occurrence, support resistance has negative and positive relationship with physical parameters (e.g., TCT and IRT) and mechanical properties (e.g., TCEM and IREM), respectively.