• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.3 s.55
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• pp.135-144
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• 2009

The cable system of suspension bridges is a very important non-elastic element which caries an external load by a tension force of the cable, such that creates the integrity of a structure. It is not easy to find if cable system have been changed by the maintenance activities such as repairs or reinforcement. Sometimes the maintenance can cause structural deformations and changes of the tension force in cables. In most cases, the cable stayed bridges are managed by health monitering system, however, the main cable of suspension bridges need to develop more accurate and efficient monitoring system. The Namhee Bridge was constructed 35 years ago and it has been continually repaired and reinforced after then. This study describes the behavior of the cable system by analysing many of inspective reports and by using the results of hanger rope test and for the shape of main cables surveys.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.94-98
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• 2003

Remotely Operated Vehicle. ROV is a new concept equipment being made to replace the manned systems for investigating the deep sea environment. This paper presents the dynamic cable response during ROV launching considering the coupling effects of ship motion. By the harmonic response analysis, the variations of cable tensions were obtained. Harmonic forces in head/beam sea states were calculated by the concept of relative acceleration which obtained by ship motion analysis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.4
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• pp.127-134
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• 2005

Design and construction of long-span bridge are recently increasing by development of computer technology. Specially, cable stayed bridge and suspension bridge having cable component are representative of long-span bridge may do. Therefore, this paper a present a methodology for cable tension force monitoring in cable-stayed bridge under construction using acceleration data acquired by the vibration method. To improve accuracy construction, all stay cables are measured, according to 4-step construction stage and change of temperature.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.4
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• pp.55-66
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• 2024

In order to safely use thermoplastic (TP) cables in high-voltage direct current (HVDC) systems, it is necessary to analyze the life loss rate of the cable due to system fault that may occur during operation through various research and tests. In this paper, we analyzed the insulation life loss rate of TP cable according to the type of faults that may occur during HVDC system operation. Electric power due to fault was applied to the TP cable model, and the life loss rate of the insulator was analyzed by applying the Arrhenius-Inverse Power Model (IPM) based on the analysis results through the 2D finite element method. As a result of the analysis, the life loss rate of the insulator was highly influenced by the electric field strength, and the loss rate was highest inside the insulator when a fault occurred. These results can be used as important characteristics in the early design stage for commercialization of TP cables.

• Journal of Ocean Engineering and Technology
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• v.30 no.6
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• pp.458-467
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• 2016

In this paper, a strongly coupled method for investigating the interaction between a cable and tow-fish is presented. The nodal position finite element method was utilized to analyze the nonlinear cable dynamics, and 6DOF equations of motion were employed to describe the 3D rigid body motion of the tow-fish. Combining cable and tow-fish systems into a single formulation allowed the two nonlinear systems to be strongly coupled into a unified nonlinear system. This strongly coupled system was numerically integrated in the time domain using a predictor/multi-corrector Newmark algorithm. To demonstrate the validity, efficacy, and applicability of the current approach, two different scenarios (virtual and sea trial) were simulated, and the simulation results were validated using the physical plausibility and the sea trial test.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.313-316
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• 1995

In this study, in case the lead sheath of XLPE cable (radius : 15cm, inner conductor radius : 5cm, insulation paper raidius : 6cm, dc voltage : 1MV) is harmed, so that breakdown process by inhomogeneous eletric field is simulated with Finite Element Method. The result of simulation showed that defect of lead sheath layer caused breakdown.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.105-111
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• 2018

This study aims to evaluate the safety for cable stayed bridge due to damages on the cable system. Many cable supported bridges, including cable stayed bridge and suspension bridge, have been built in the Korean peninsula. This requires efficient maintenance and management since this structure has complex structural components and system. This large structure also often faces risks either from manmade or natural phenomenon. In 2015 one cable-stayed bridge in South Korea had been struck by a bolt of lightning on the cables. This event had led to fire on cables. These cables had been damaged and putting the bridge at risk. This bridge was back in used after a few weeks of investigations and replacements of the cables. However, enormous social and economic expense were paid for recovery. After this event risk based management for infra structures is required by public demands. Therefore, this study was initiated and aimed to evaluate risks on the cable system due to potential damages. In this paper one cable-stayed bridge in South Korea was selected and investigated its safety based on the damage scenarios of cable system for efficient and prompt management, and for supporting decision making. FEM analysis was conducted to evaluate the safety of the bridges due to damages on the cable system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.1
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• pp.55-63
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• 1993

Finite element analyses are conducted with stochastic elastic moduli when truss structures are subjected to static loads of a deterministic nature. Stochastic stiffness matrix is derived from stochastic shape functions and numerical analyses are performed within the framework of the Monte Carlo method. Analysis methods are verified for the space truss and applied to cable stayed bridge for determining the cable force.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.11a
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• pp.36-38
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• 2014

디지털 케이블 방송 시스템은 기존의 아날로그 케이블방송과 달리 하나의 6MHz 주파수 대역에 여러 방송채널들을 전송하고 있다. 즉, MPEG2 또는 H.264/AVC 등 비디오 압축 방식으로 인코딩된 여러 방송채널들과 각 채널의 대한 정보를 제공하기 위한 PSI 정보를 생성하여 멀티플렉싱하여 6MHz 주파수 대역으로 전송하는 방식으로 서비스를 제공한다. 하지만, 근본적으로 디지털 케이블 방송에서는 방송채널 변경 시 QAM Tuner의 주파수 Locking 및 디멀티플레싱, PSI 정보 파싱을 통한 채널 정보 획득, 비디오 및 오디오 디코딩을 위한 RAP(Random Access Point) 획득, 스크램블채널을 위한 ECM 획득 등의 시간 지연이 발생함에 따라 아날로그 케이블방송과 비교하여 상당한 채널 변경 지연이 발생한다. 이러한 이유로 디지털 케이블 방송 서비스의 품질 향상을 위해서는 채널 변경 시간 지연을 최소화하기 위한 연구가 필요하다. 따라서, 본 논문에서는 채널 변경 지연 요소들을 분석하고, 채널 변경 지연을 최소화하기 위한 기법을 제안한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.2C
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• pp.184-190
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• 2002

This paper compares and analyzes and analyzes the transmission performance of the OpenCable system and the DBD-C system which are adopted as the digital CATV transmission standard in U.S.A. and Europe respectively through computer simulation under the same channel environment. We considered the channel environment including the random noise and the CTB (Composite Tripple Beats) noise as channel impairments in order to compare the two standard fairly. Additionally, we analyzed the transmission performance of the OpenCable system for the various interleaving depths. We implemented each transmission system by software, and we analyzed BER values with respect to the C/N in order to compare their transmission performance. As a result of the computer simulation, to get the BER of ${10}^{-6}$ the OpenCable system requires 1.2 dB kiwer C/N than the DVB-C system in the 64-QAM mode, and the two system require similar C/N in the 256-QAM mode.