• 한국컴퓨터산업학회논문지
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• 제6권2호
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• pp.357-364
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• 2005

최근 들어 우리나라에서는 설치의 간편성과 높은 신뢰도를 가진 전력케이블의 사용이 증가하고 있다. 전력케이블은 출고 전에 IEEE std. 404-1993 시험을 거쳐 안정성을 확인하고 있지만 포설시 발생하는 접속부 내부의 결함으로 인하여 많은 문제가 발생하고 있다. 특히 불순물 혼입 또는 공극 발생시 고장율은 증가하게 된다 부분방전 검출은 포설 후 전력케이블의 상태를 관측할 수 있는 유용한 방법이다. 본 연구에서는 부분방전 특성을 평가하고자 케이블 접속재인 EPR과 케이블 절연체인 XPLE 사이에 인공 결함을 발생시킨 후 데이터 취득 시스템을 이용하여 $\Phi-q-n$ 특성을 검출하였으며, 부분방전의 정량적 해석을 위해 필요한 통계량을 계산하였으며, 신경망 모델을 적용하여 패턴 분석을 수행하여 $88\~96\%$의 구별이 가능하였다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제18권2호
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• pp.269-278
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• 1996

To overcome the limitations of conventional microsurgical tissue transfer, experimental creation of various neo-flaps using the vessel implantation technique has been reported. We have performed some experiments of fabrication of neo-osseous flap with local vessels and iliac bone slabs to know that the flap vascularity and neo-angiogenesis are achieved enough to microtransfer. As a next step of our previous experiments, the flap viability and the histologic change between the recipient bone and neo-oseous flap was assessed after microsurgical transplantation. The flap was created on the rabbit femoral region(n=25) using femoral vessel and the iliac bone segments($2.5{\times}1.5cm$ in size). Three weeks after neovascularization, the newly formed flap was harvested and microtransferred to the mandibular defect. As a control, contralateral mandibular defect was created and reconstructed with conventional free iliac bone graft. Scintigrams of experimental group performed 3 days after microtransfer showed hot uptake, while that of control poor uptake. Histologic and vital stain labeling study revealed good bone viability and vascularity of neo-osseous flap. In conclusion, prefabricated neo-osseous flap of our model could be transferred to the recipient site with retaining the flap viability and showed advantages over the conventional bone graft in that it was living bone graft.

• 구강회복응용과학지
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• 제33권4호
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• pp.299-306
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• 2017

본 증례는 완전한 디지털 workflow로 단일 치아 임플란트 지지형 보철물을 즉시 부하하여 수복한 증례이다. 하악 제1대 구치 상실로 내원한 환자로, 구강 스캐너로 구내 디지털 인상채득 후, CT데이터와 디지털 스캔 데이터를 통해 제작한 수술용 가이드를 이용하여 임플란트를 식립하였다. 술 후 1주일 후, 맞춤형 지대주와 임시치아를 체결하여 즉시부하 하였다. 술 후 8주 후 지대주 레벨에서 구강스캐너를 이용하여 디지털 인상채득 후, 술 후 3개월에 지르코니아 최종 보철물을 장착하였다. 본 증례는 환자의 만족도 및 정확성 면에서 만족할 만한 결과를 나타내었으며, 완전한 디지털 과정을 통한 수복 결과 정확성, 심미성, 기능성 면에서 만족할 만한 결과를 나타내었기에 보고하는 바이다.

• 한국BIM학회 논문집
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• 제8권2호
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• pp.41-50
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• 2018

The current study focused on the utilization of building information modeling (BIM) data in steel-frame structures, which help to reduce project durations because they employ prefabricated structural members that are assembled on-site. In addition, a business process model was proposed using BIM data collected during the preconstruction, structural steel fabrication, and on-site construction phases of an actual steel-frame project. The ultimate expectation is that BIM data support at each phase, as well as the increased understanding among project participants, will result in an increase in project management productivity. The results from the current study are summarized as follows: To implement a BIM capable of application to steel-frame projects and data utilization, existing theories were studied to develop the construction project steps, both generally into the preconstruction (A1), steel fabrication (A2), and on-site construction phases, (A3) and specifically into 19 BIM-applicable phases. Based on the derived BIM-applicable phases, the model elements of the BIM object were identified, and the shortcomings of existing steel-frame projects were ameliorated, resulting in an improved data flow model. Moreover, for the proposed BIM data flow to progress efficiently, the BIM specialist needs to be well-acquainted with the phase-specific three-dimensional (3D) model output, and the infrastructure to construct an error-free 3D model must be provided. Based on the actual construction example, the BIM data utilized steel-frame projects - via production reports, clash checks, two-dimensional (2D) drawings, four-dimensional (4D) simulations, and 3D scanning - to make cooperation and communication among participants easier.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.336-345
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• 2010

GS E&C was awarded the contract for the construction of Hanoi - Hai Phong Expressway Package EX-7 from Station Km 72+000 to Station Km 81+300 in December 2008. This project is the $7^{th}$ contract package of the 105.5 km long expressway near Hai Phong city, which includes a FCM-styled bridge along with high embankments over soft ground. For these high embankments, there is a need to treat the soft soil for improving the overall stability during construction and for reducing the post-construction settlement of the expressway. The Designer of this project had adopted four (4) different types of ground improvement techniques to treat the soft ground, including the prefabricated vertical drains (PVD), sand drains (SD), pack drains (PD, or sometimes called packed sand drains), and sand compaction piles (SCP). The main focus of soft soil treatment should be paid attention to the residual settlement after construction. In current design, however, it appeared that the secondary compression (or creep) of the improved soil layer and the consolidation settlement of the lower untreated compressible soil layer have been neglected in the estimation of the post-construction settlement. These uncalculated residual settlements may not only unsatisfy the design criteria but also raise serious problems during service period of this expressway. In this paper, the subsoil condition and current design were reviewed focusing on the employed soft soil treatment method and expected residual settlement.

• 한국컴퓨터산업학회논문지
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• 제6권2호
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• pp.279-286
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• 2005

최근 들어 우리나라에서는 설치의 간편성과 높은 신뢰도를 가진 전력케이블의 사용이 증가하고 있다. 전력케이블은 출고 전에 IEEE std. 404-1993 시험을 거쳐 안정성을 확인하고 있지만 포설시 발생하는 접속부 내부의 결함으로 인하여 많은 문제가 발생하고 있다. 특히 불순물 혼입 또는 공극 발생시 고장율은 증가하게 된다. 부분방전 검출은 포설 후 전력케이블의 상태를 관측할 수 있는 유용한 방법이다. 본 연구에서는 부분방전 특성을 평가하고자 케이블 접속재인 EPR과 케이블 절연체인 XPLE 사이에 인공 결함을 발생시킨 후 데이터 취득 시스템을 이용하여 $\Phi-q-n$ 특성을 검출하였으며, 부분방전의 정량적 해석을 위해 필요한 통계량을 계산하였으며, 신경망 모델을 적용하여 패턴 분석을 수행하여 $88\~96\%$의 구별이 가능하였다.

• 한국강구조학회 논문집
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• 제25권6호
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• pp.635-647
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• 2013

PSRC 기둥은 앵글을 콘크리트에 매입시킨 기둥으로, 단면의 외곽 코너에 배치되는 앵글이 기둥의 휨-압축에 저항한다. 본 연구에서는 KBC 2009에 따라 압축력을 가한 기둥에 대하여 횡방향 반복가력 실험을 통하여 내진성능을 검증하였다. 기둥 종류, 연속후프근 적용, 앵글에 스터드 적용을 실험 변수로 고려하였으며, 2/3 스케일을 갖는 한 개의 SRC 합성기둥과 세 개의 PSRC 합성기둥을 실험하였다. 실험결과, KBC 2009로 예측한 PSRC 합성기둥의 하중재하능력은 실험결과와 잘 일치하였으며, 변형능력과 에너지 소산에 있어서 우수한 성능을 보여주었다. PSRC 합성기둥은 반복하중으로 인한 콘크리트 피복 탈락 이후, 앵글 및 주철근의 좌굴에 의해 실험체의 하중재하능력이 감소하였다. 특히, 연속후프근을 적용한 PSRC 합성기둥은 앵글의 조기 국부좌굴이 억제되어 기존 PSRC 합성기둥에 비해 연성능력이 향상되었다.

• 한국안전학회지
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• 제13권4호
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• pp.221-229
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• 1998

This study, with a view point to prevent accidents arising from steel structure, construction process, has taken an approach of reviewing related materials and construction safety guidelines, conducting questionnaire surveys and on field surveys. This study has also analyzed and classified accident cases and disclosed elements concerned with those accidents. A comparative analysis of the disclosed elements against the statutory provisions regarding industrial safety and it showed that strict observance of safety rules of the accident prevention measures in industrial safety standards will result in a decrease in accidents. It is concluded, however, that additional accident prevention measures, as suggested below, should be implemented for performing of more practical and positive accident prevention. 1) Thorough review and preparation at pre-working stage at sites : Such elements of fall preventing facilely as supporting ropes and steel fabrications for safety guard rails should be initially reflected on detailed drawings and shop drawings so that they can be installed in advance at fabricating plants. 2) Sets of steel frame stairs for work platform should be installed or secured with priority and temporary installation of such prefabricated platform as scaffolds should be installed in advance with those platform attached to the frame members on the ground whenever possible before they are lifted. 3) A decrease in the rate of accident by more than 10% on Tuesdays and Thursdays, has been shown from the accident analysis so schedule of construction process should consider possible weekday of high risk of accidents such as Tuesday and Thursday. 4) An array of systemized safety activities should be adopted, such as legal installation of safety facilities based on advance safety management plan, maintenance of safety for machinery and construction equipment, and strict compliance of safety rules by workers.

• Steel and Composite Structures
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• 제29권1호
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• pp.1-22
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• 2018

Multi-storey precast concrete skeletal structures are assembled from individual prefabricated components which are erected on-site using various types of connections. In the current design of these structures, beam-to-column connections are assumed to be pin jointed. Welded plate beam to-column connections have been used in the precast concrete industry for many years. They have many advantages over other jointing methods in component production, quality control, transportation and assembly. However, there is at present limited information concerning their detailed structural behaviour under bending and shear loadings. The experimental work has involved the determination of moment-rotation relationships for semi-rigid precast concrete connections in full scale connection tests. The study reported in this paper was undertaken to clarify the behaviour of such connections under symmetrical vertical loadings. A series of full-scale tests was performed on sample column for which the column geometry and weld arrangements conformed with successful commercial practice. Proprietary hollow core slabs were tied to the beams by tensile reinforcing bars, which also provide the in-plane continuity across the connections. The strength of the connections in the double sided tests was at least 0.84 times the predicted moment of resistance of the composite beam and slab. The secant stiffness of the connections ranged from 0.7 to 3.9 times the flexural stiffness of the attached beam. When the connections were tested without the floor slabs and tie steel, the reduced strength and stiffness were approximately a third and half respectively. This remarkable contribution of the floor strength and stiffness to the flexural capacity of the joint is currently neglected in the design process for precast concrete frames. In general, the double sided connections were found to be more suited to a semi-rigid design approach than the single sided ones. The behaviour of double sided welded plate connection test results are presented in this paper. The behaviour of single sided welded plate connection test results is the subject of another paper.

• Computers and Concrete
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• 제17권1호
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• pp.1-27
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• 2016

Final construction project cost is significantly determined by construction rate. The Industrialized Building System (IBS) was promoted to enhance the importance of prefabrication technology rather than conventional methods in construction. Ensuring the stability of a building constructed by using IBS is a challenging issue. Accordingly, the connections in a prefabricated building have a basic, natural, and essential role in providing the best continuity among the members of the building. Deficiencies of conventional precast connections were observed when precast buildings experience a large induced load, such as earthquakes and other disasters. Thus, researchers aim to determine the behavior of precast concrete structure with a specific type of connection. To clarify this problem, this study investigates the capacity behavior of precast concrete panel connections for industrial buildings with a new type of precast wall-to-wall connection (i.e., U-shaped steel channel connection). This capacity behavior is compared with the capacity behavior of precast concrete panel connections for industrial buildings that used a common approach (i.e., loop connection), which is subjected to monotonic loading as in-plane and out-of-plane loading by developing a finite element model. The principal stress distribution, deformation of concrete panels and welded wire mesh (BRC) reinforcements, plastic strain trend in the concrete panels and connections, and crack propagations are investigated for the aforementioned connection. Pushover analysis revealed that loop connections have significant defects in terms of strength for in-plane and out-of-plane loads at three translational degrees of freedom compared with the U-shaped steel channel connection.