• Journal of Korean Society of Steel Construction
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• v.9 no.2 s.31
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• pp.181-191
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• 1997

Before cables are constructed, tower of suspension bridge is behaved as a cantilever type. Buffeting occured by unsteady loading of the tower due to velocity fluctuation in the oncoming flow has a wind velocity consistent with fundamental frequency of the tower and may give rise to large response by the tower resonance. To reduce the dynamic response by buffeting, the behavior of tower with TMD(Tuned Mass Damper) has studied using finite element method in time domain. The buffeting was obtained by transforming the velocity spectrum in frequency domain to random variable in certain time domain. The most probable maximum displacement which can be occured during the time interval was obtained using peak factor. The optimum location for TMD installation and TMD specification were decided by parametric study. Also, the effect of vibration control about various wind velocity was studied by the TMD which has optimum specification and location.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.1
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• pp.51-57
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• 2013

Leak detection, the system is controlled by humanity's precious water resources, prepare for natural disasters and prevent damage to buildings and various industrial facilities. Especially because it causes serious environmental pollution, chemicals or oil spills, leak detection of various liquid(oil, water), the point at which the liquid leak is detected early on, and minimize environmental pollution, prevent damage of the equipment due to the leak, and the country's precious water resources to be used safely. In this paper, we solve these problems by using specialized film sensor, any person who is not a skilled technician, equipment or walls anywhere can be easily installed. also reduce unnecessary circuit, If film sensor is connected to operate, have a big competitive price, the detection of liquid and the surrounding environment according to, the sensor film that can set the sensitivity control, and monitoring system was implemented.

• Journal of the Korean Society for Railway
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• v.18 no.3
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• pp.232-240
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• 2015

Two types of track circuits are used in high speed railway car depots: one is High Voltage Impulse Track Circuit(HVITC); the other is AF track circuit. HVITC detects train occupation of blocks and broken rail; the AF track circuit is used for train onboard control system pretesting before departure. This testing is used to transmit train control information through the AF track circuit. The two systems are switched in turns for testing. We propose a system in which the AF track circuit is replaced by a loop cable that is installed on the inside rail; as such, engineers do not need to switch the systems. In cases in which the two systems run simultaneously, mutual interference may occur. In this paper, we identified this mutual interference by modeling of the two circuits.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.1
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• pp.1-13
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• 2009

A study for the nonlinear solution strategies to predict the ultimate behavior of a curved PSC cable-stayed bridge with complex geometry and highly nonlinear characteristics is presented. The load and displacement control strategies are used and found to be stable for the nonlinear solution of the PSC bridge up to the moderately excessive load. The ultimate analysis of curved PSC cable-stayed bridge using these solution strategies is not converged due to the propagation of the cracks in the wide range of the concrete elements and excessive variation of the stresses in the concrete elements and cables according to the complex geometry. The load control strategy using scale-down of the unbalanced loads is proposed as an alternative method for the case that the solution is not converged due to the severe nonlinearities involved in the PSC structures like a curved PSC cable-stayed bridge. Through the ultimate analysis of the PSC girder, the accuracy and the stability of the proposed solution strategies are evaluated. Finally, the numerical results for the ultimate analysis of the curved PSC cable-stayed bridge using scale-down of the unbalanced loads are compared with those obtained from other investigator. The validity of the proposed nonlinear solution strategy is demonstrated fairly well.

• Journal of Aerospace System Engineering
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• v.18 no.1
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• pp.37-45
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• 2024

This paper presents a design approach for passive vibration control to reduce vertical vibrations transmitted to the control unit during hovering flight of a quadrotor drone. Ground vibration test simulation based on finite element model was performed for forced vibration analysis of the quadrotor drone. First, modal analysis was performed to evaluate dynamic characteristics. Forced vibration response analysis was then performed to obtain the steady-state response within the operating frequency range under the hovering flight condition. Furthermore, to obtain the vibration reduction effect, a viscous damping tape was applied at positions that could induce vibrations transmitted to the control unit under the same conditions. Such a passive vibration control approach was investigated. Relevant vibration reduction effect was assessed with respect to the application of damping materials and the attachment position.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.497-504
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• 2005

Stay cables, such as are used in cable-stayed bridges, are prone to vibration due to their low inherent damping characteristics. Several methods have been proposed and implemented to mitigate this problem, though each has its limitations. Recently some studies have shown that active and semiactive control system using MR (Magnetorheological) damper can potentially achieve both higher performance levels than passive control system and adaptability with few of the detractions. However, a control system including a power supply, controller, and sensors is required to maximize the performance of the MR damper and this complicated control system is not effective to most of large civil structures. This paper proposes a smart passive damping system using MR dampers by introducing electromagnetic induction (EMI) system as an external power source to MR damper and verified the performance of smart passive damping system for mitigating the vibration of stay cables. The performances of smart passive damping system are compared with those of linear viscous damper and passive-mode MR damper.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.58-60
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• 2012

스마트 TV 및 스마트 셋톱박스와 같은 가정내의 고정형 스마트 기기에 대한 관심이 증가하고 있으며, 이러한 기기는 가정의 미디어 서비스를 제어하는 콘텐츠 허브로 발전하고 있으며, 홈 플랫폼의 포괄적 개념으로 정의할 수 있다. 이러한 홈 플랫폼은 IPTV, 지상파, 케이블, 및 위성 등의 다양한 방송 콘텐츠를 수용할 수 있으며, 모바일 단말 등의 외부 기기와의 연동을 통해 다양한 형태의 콘텐츠에 대해서 접근이 가능하다. 이와 관련하여 실제 서비스 제공이 가능한 기술은 방송 콘텐츠와 시간적으로 연계된 부가정보를 사용자의 모바일 단말에서 제공해 주는 서비스 기술이다. 또, 가정내의 홈 플랫폼을 통해 접근 가능한 다양한 방송 및 콘텐츠 부가정보를 통합적으로 취합하여 하나의 콘텐츠 가이드를 생성하고, 이를 개인 모바일 단말로 전송하여 사용자의 콘텐츠 소비 만족도를 보다 향상할 수 있는 기술에 대한 관심 역시 증가하고 있다. 본 논문에서는 홈 플랫폼에서 방송 수신 정보, 로컬 콘텐츠 및 모바일 단말의 저장 콘텐츠 정보를 기반으로 부가정보를 정합하여 ECG를 생성하고, 이를 모바일 단말에 전송하여 콘텐츠 서비스를 제공하는 플랫폼을 설계하고, 구현하였다. 통합 ECG 생성을 위한 콘텐츠의 메타데이터는 TV-Anytime 표준을 기반으로 적용되어 플랫폼간 상호 연동성이 확보되도록 하였다.

• JOURNAL OF ELECTRICAL WORLD
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• s.310
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• pp.67-72
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• 2002

미쓰비시(삼릉)전기 플랜트건설총괄부의 전력플랜트 건설공사는 수력$\cdot$화력플랜트 및 변전설비를 대상으로 하고 있으며, 수차$\cdot$수차발전기$\cdot$가스절연개폐장치(이하 ''GIS''라 한다), 변압기, 배전반 및 관련 제어기기 등의 설치 및 기기간의 배선공사 설계$\cdot$시공을 담당하고 있다. 최근의 전력플랜트를 둘러싼 일본의 시장환경은 신설 플랜트는 감소하고 갱신$\cdot$기기개수(개조, 수선) 공사의 비율이 커지고 있으며, 신설$\cdot$개보수 공사를 불문하고 공사품질의 유지와 공사비 저감을 위한 공법$\cdot$작업의 개선과 설계$\cdot$계획 업무의 합리화를 추진하여 왔다. (1) 기자재 개발에 의한 공법$\cdot$작업 개선 대형수력발전기의 로터조립용 다브테일키 박아놓기(타입)장치, 스테이터코일 분해(갱신)용 코일 엔드절단 및 코일뽑기공구, 터빈발전기 센터링용 유압잭, GIS 설치용 작업용발판을 개발하여 적용함으로써 공법 개선과 작업효율의 향상을 실현하였다. (2) 공사계획 방법의 개선 변전플랜트에서의 공기단축을 목적으로 하는 현지 설치 최적공정 책정방법의 개발$\cdot$적용, 또한 화력플랜트에서의 공사물량의 저감과 설계작업의 효율 향상을 목적으로 하는 케이블 배선 설계$\cdot$계획 방법의 개발 및 적용으로 설계업무의 개선, 공사비 저감을 도모하였다.

• Journal of Korean Society of Steel Construction
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• v.22 no.2
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• pp.197-208
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• 2010

An under-tension system is frequently employed for large-span structures to reduce the deflection and member size. In this study, a microgenetic algorithm was used to find the optimum cross-section of truss structures with an undertension cable under transverse loading. Maximum deflection, allowable stress, and buckling were considered constraints. The proposed approach was verified using a 10-bar truss sample that shows good agreement with the previous results. In the numerical results, minimum-weight design of the under-tension structure was performed for various magnitudes of pretension.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.3
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• pp.105-110
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• 2005

Programmable Logic Controller(PLC) is the most widely utilized among many sorts of existing controller for the design of factory automation control system, and study about a PLC language is peformed actively. In this paper, we proposed the encoding module that we increase input points when increased of the input machine which is going to control it in the FA design that used PLC. Input point is going to be extended with 2-3 points in the state that cannot equip input unit in basic base any more. Then an extension base, a power supply, an extension cable and an output nit must be equipped particularly. Then a cost must be added very much. This paper proposed the encoding module which extended an input in a small quantity, and we confirmed a feasibility through a simulation.