• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.53-58
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• 2002

Sheath circulating current is increased as the change of sheath mutual impedance which is caused by imbalance of cable system, and different section length between joint box. If excessive current flows in sheath. sheath loss will be increased and then transmission capacity of underground transmission system is reduced. Accordingly, This paper proposed sheath current reduction device using resistor and reactor and proved the reduction effect of that device using EMTP/ATP. And also in this paper, when transients are occurred at the underground system with reduction device by ground fault and lightning surge. we analyzes transient effect of system variously. From this result. authors establish the protection methods of sheath circulating current reduction device.

• 소성∙가공
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• 제17권8호
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• pp.607-612
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• 2008

The groove rolling is a process that transforms the bloom or billet into a shape with circular section through a series of rolling. Inhibition of surface defect generation in groove rolling is a matter of great importance and therefore many research groups proposed a lot of models to find the location of surface defect initiation. In this study, we propose a model for maximum shear stress ratio over equivalent strain to catch the location of surface defect onset. This model is coupled with element removing method and applied to box groove rolling of POSCO No.3 Rod Mill. Results show that proposed model in this study can find the location of surface defect initiation during groove rolling when finite element analysis results is compared with experiments. The proposed criterion has been applied successfully to design roll grooves which inhibit the generation of surface defect.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.593-598
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• 2009

This paper presents a preliminary study to monitor the lateral behavior of pile foundation using multiplexed fiber Bragg grating (FBG) sensors. In the preliminary study, an 1.7 meter long cantilever beam with the shape of square hollow box was fabricated and tested under the static loading. Four FBG sensors were multiplexed in a single optical fiber and installed into the top and bottom of the cantilever beam. The strains are directly measured from FBG sensors followed by curvature calculations based on the plane section assumption. Vertical deflections are then estimated using the regression analyses based on the geometric relationships. It has been found that excellent correlation with conventional sensing system was observed. The success of the test encourages the use of the FBG sensing system as a monitoring system for pile foundations. However, further consideration should be given in the case of the sensor malfunction for the practical purpose.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.857-862
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• 2007

The purpose of this research is to compare the stiffness increment effects with the floor plan shapes by the stiffness increment factors. For this, we generated the standard floor plans with Box and T type shapes. Then applied the stiffness increment factors -outrigger, material strength, member section- to those floor plans, and generated several alternative analysis models that make the effects of the factors to the lateral displacement exposed. Finally, we analyzed the stiffness increment effects and compared with each other by the stiffness increment factors. As a result, we found that the increment effects have not influence to floor plan shapes, and orders of stiffness increment effects are outrigger, core wall and material strength. We expect that the results of this study could be effectively utilized in the schematic structural design of tall buildings.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2010년도 정기 학술발표대회
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• pp.41.2-41.2
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• 2010

하천, 해상 등에 위치한 교량 설계시 선박충돌을 방지하기 위해 교각 위치를 변화시킬 필요성이 발생한다. 이 때, 교각 위치에 따른 변단면을 갖는 PSC(Prestressed concrete) 박스거더의 형상 변화를 효과적으로 변경하기 위해 고려해야하는 구속조건을 추출하고 정의하였다. PSC 박스거더는 변단면 시공에 일반적으로 적용되는 FCM(Free cantilever method) 공법이 착용된 교량을 착용했으며, 구속조건 정의를 위해 설계지침서를 분석하여 구속조건으로 작용하는 매개변수를 추출하였다. 정의한 구속조건의 적용성을 검증하기 위해 파라메트릭 모델링을 수행하였으며, 그 결과로 생성된 모델에 대한 물량을 산출하여 대상교량에서 산출된 실제 물량과 비교 분석하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 춘계학술대회 논문집
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• pp.401-407
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• 2001

Out of 412km long Kyung-bu high-speed railway, 302km was designed in tile form of either bridges or tunnels. Most of bridges were designed to be prestressed concrete box girder type. The precast span method was selected because of good quality of bridge section secured by factory manufacturing, fast construction speed, low construction cost with mechanized construction and the safety fur field workers. The precast span method has been mainly utilized in bridges consisted of repeated simple spans. However, we applied the precast span method to continuous bridge for high-speed railway Since it was the first attempt to apply ate precast span method to a continuous bridge for high-speed railway, many design and construction details were studied and implemented in the construction. Design and construction processes of a continuous bridge construction using tile precast span mettled are briefly described in this paper.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.195-201
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• 2003

A fibered element for the material and geometric nonlinear analysis of three-dimensional reinforced and prestressed concrete frame is presented. The fibered frame element is idealized as an assemblage of concrete and reinforcing steel fibers in order to account for varied material properties within the cross section of the frame element through elastic, cracking and ultimated stages of materials. Prestressing tendon is modeled as an assemblage of multilinear prestressing steel segments each of which spans a frame element. The contribution of each prestressing steel is added directly to the fibered frame element. Numerical results from the ultimate analysis of three-dimensional PSC box girder are compared with those obtained from other investigator. The validity and the capability of the present nonlinear analysis model is well demonstrated.

• 대한전기학회논문지:전력기술부문A
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• 제55권11호
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• pp.468-475
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• 2006

This paper reviews the energy characteristics of oil filled cables in transient state such as grounding fault and lightning surge. Artificial grounding fault test was firstly performed in 2003 for the analysis of arc voltage and breakdown energy according to the fault current. In this paper, energy of OF cable is variously analysed at joint box based on the actual test. Then more various conditions such as installation types, section lengths and CCPU(Cable Covering Protection Unit) connection types are applied for the simulation using EMTP when the single line to ground fault and direct lightning stroke are occurred on actual underground power cable systems and combined power cable systems, respectively. Finally, the energy by the length of crossbonded lead and grounding lead as well as fault lasting time is also calculated using EMTP simulation.

• 한국전자거래학회지
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• 제8권3호
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• pp.69-86
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• 2003

보호프로파일(Protection Profile PP)은 방화벽과 스마트카드와 같은 정보보호제품의 특정제품군에 대한 공통 보안기능 및 보증 요구사항 명세서라 할 수 있다. 특히, PP내의 평가대상물(Target of Evaluation : TOE) 보안환경 부분은 TOE의 물리적 환경, 보호해야할 자산 및TOE의 용도를 분석하여 가정사항, 위협 및 보안정책을 기술해야한다. 본 논문에서는 PP내의 보안환경 부분 중 위협 문장을 개발 또는 작성하는 방법을 제시한다. CC(Common Criteria)의 위협문장 작성지침과 기존의 위협관련 요구사항. 26종의 실제 PP들과 CC Tool BOX/PKB의 위협문장들을 조사 분석하였다. 이를 토대로 하여 새로운 자산의 분류체계와 위협문장 생성을 위한 잘 정의된 위협문장의 판단규칙을 제시하였다.

• 대한토목학회논문집
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• 제34권1호
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• pp.1-8
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• 2014

이 논문에서는 장경간 케이블 교량의 콘크리트 주탑에 대한 온도 측정과 분석을 다루고 있다. 부산거제연결도로의 거가대교의 시공 중에 주탑의 여러 단면에 온도센서가 설치되었으며 주탑 4면의 두께방향의 온도와 주탑 주위의 대기온도가 계측되었다. 1년간의 계측자료를 바탕으로 주탑 단면내의 온도분포가 분석되었으며 이 분석결과를 국내외의 온도분포에 대한 설계기준과 비교하였다. 그 결과 주탑 단면의 평균온도와 단면 내 온도분포는 콘크리트 거더의 평균온도와 수직온도분포의 기준을 적용할 수 있음을 확인하였다. 이러한 온도특성에 대한 주탑의 거동을 3차원 유한요소 모델링을 사용하여 해석하였으며 거가대교 주탑의 경우 온도에 의한 주탑 상부 최대변위는 동서, 남북 방향으로 각각 0.056m, 0.121m 인 것으로 나타났다.