• Journal of the Korean Society of Industry Convergence
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• v.25 no.5
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• pp.773-782
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• 2022

Estimation of cable tension through proper measurements is one of the essential tasks in evaluating the safety of cable structures. In this paper, a study on cable tension estimation using the built-in accelerometer and camera in a smartphone was conducted. For the experimental study, visual displacement measurement using a smartphone camera and acceleration measurement using a built-in accelerometer were performed in the cable-stayed bridge model. The estimated natural frequencies and transformed tensions from these measurements were compared with the theoretical values and results from the normal visual displacement method. Through comparison, it can be seen that the error between the method using the smartphone and the normal visual displacement is sufficiently small to be acceptable. It has also been shown that those errors are much smaller than the difference between the values calculated by the theoretical model. These results show that the deviation according to the type of measurement method is not large and it is rather important to use an appropriate mathematical model. In conclusion, in the case of cable tension estimation, it can be said that the visual displacement measurement and acceleration using a smartphone can be a sufficiently applicable method, just like the normal visual displacement method. It is also noteworthy that the smartphone accelerometer has a larger magnitude error and has more limitations such as high-frequency sampling instability compared to the visual displacement method, but shows almost the same performance as the visual displacement method in this cable tension estimation.

• 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.

• Korean journal of communication and information
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• v.57
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• pp.137-159
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• 2012

This is a dissertation about the state and cable television industry relationship during the early days of Kim Dae-Jung administration(1998.2-2000.1) in Korea. This study adopted historical approach and methodology of archival research. Offe's state theories of reproduction of late capitalism and the concept of Korean patriarchal state-led capitalism were suggested in this paper. Offe argued that the goal of the late capitalist state is successful capital accumulation and democratic legitimation with bureaucratic rationalization. For this purpose, the state intervenes market structuring by various plans and national policies. The Kim Dae-Jung administration reorganized cable television market with neo-liberalistic strategies and corporatist forms of policy-making. The government negotiated capitalists and civil society for managing capitalistic economy and cable television market in a horizontal relationship. Successful consequences of the market growth resulted in generating mass loyalty. The former administrations to the contrary, invisibly arranged state-led capitalism was an only alternative to the Kim Dae-Jung administration. The Korean state-led capitalism evolved gradually into different forms.

• Journal of the Korea Computer Industry Society
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• v.4 no.4
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• pp.579-588
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• 2003

There are many unfavorable conditions that lead to shortening life of cable by causing dielectric breakdown and aging such as field concentrations occurring in intermediate materials linking each cables, penetration of various impurities, and undermining of cable insulation layers. This paper simulated investigated partial discharge properties of XLPE which is widely used for ultra high voltage cable insulation materials and EPDM which is being used as insulation layer of cable joint materials kit, using Boundary Element Method. The result of computer simulation showed that inner-Void defect caused silicone oil to weaken the E-field effect. and we also found that E-field distribution in EPDM remained relatively lower than that in XLPE.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.4_2
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• pp.637-644
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• 2020

Because suicide accidents sometimes were happened in grand bridges over rivers or sea water recently, it will be necessary that prevention measures be made preparation in advance from now on. Additional safety facilities must be needed in addition to existing safety facilities in such a way as this prevention measure. In order to make cable-stayed bridge safe on wind for additional safety facilities, main girder models with added safety facilities for wind-tunnel tests was made, and wind tunnel experiments was carried out to measure aerodynamic force coefficients. Also, wind-resistant analyses of 3D cable-stayed bridge were performed on the basis of wind-tunnel test results. From the wind experiments, force coefficients of main girder with added safety facilities were assessed, and it is known that there are little possibility of galloping and rotation of steel main girder. Finally, from the wind resistant analyses, it was concluded that wind-resistant safety of cable-stayed bridge was secured on wind speed 60.6m/sec.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.4_2
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• pp.587-594
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• 2022

In the 2000s, a lot of cable-type grand bridges are being built in consideration of economic aspects such as the reduction of logistics costs and the distribution of traffic volume due to rapid economic development. In addition, because the recently installed grand bridges are designed in an aesthetic form that matches the surrounding environment as well as the original function of the road bridge, and serves as a milestone in an area and is used as an excellent tourism resource, attracting many vehicles and people, there is an urgent need for a safety structure that can ensure the safety of not only vehicles but also people. In order to make cable-stayed bridge safe on wind for additional five safety structures, main girder models with and without safety structures for wind-tunnel experiments was made, and wind tunnel experiments was carried out to measure aerodynamic force coefficients. Also, wind-resistant analyses of 3D cable-stayed bridge were performed on the basis of wind-tunnel experiment results. From the wind tunnel experiments for the aerodynamic force coefficients of main girder with five safety structures and the wind resistant analyses of cable-stayed bridge without safety structure and with safety structure, it was concluded that the best form of wind-resistant safety was shown in the order of mesh, standard, bracing, hollow, and closed type. And wind-resistant safety of cable-stayed bridge with hollow and closed type on design wind speed 68.0m/sec was not secured. Finally, as five safety structures are installed, maximum rate of stress increments was shown in the order of steel main beam, steel floor beam, concrete floor beam and cables.

• Proceedings of the Korean Society for Quality Management Conference
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• 2010.04a
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• pp.55-61
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• 2010

Many enterprises are looking for counterproposals to be survival through innovation activities and to be held on their continuous businesses for their business management environments nowadays. One of the innovation activities is an improvement of Loss and reinforcement of business structure through Lean, TPM. Another one is an improvement of these innovation activities and have achieved lots of outcomes (profits). But most these activities have been applied for only the industries in Automobile, Semiconductor, Aviation, Construction with large enter in Korea. And most of minor cable enterprises don't even try to import these innovation activities excluding some how the small and medium cable enterprise can import the LEAN / 6 Sigma activities effectively with some of sample in real small and medium cable company.

• Journal of the Korea Computer Industry Society
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• v.5 no.3
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• pp.355-362
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• 2004

This paper presents the common and different results between the galloping cable and torsional oscillations in suspension bridge. Numerical results of the galloping cable and torsional oscillations in suspension bridge are presented by using the second-order Runge Kutta method under the initial conditions. This paper shows that large amplitude solution can coexist with the small amplitude one as the frequency and amplitude of the oscillation change. The differences in symmetry and transient effects are presented.

• Journal of Industrial Technology
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• v.22 no.B
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• pp.251-260
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• 2002

In this thesis, a three degrees of freedom robot, which is able to provide sufficient precision for various robot researches, has been developed. The cable mechanism is used as a basic transmission of robot joints. Based on an optimal design strategy, link and joint parameters are determined and then overall geometry of the robot is designed. As an architecture of robot control, real time control system using real time linux and RtiC-Lab(Real Time Controls Laboratory) is developed. This system, written in C and based on Linux O/S, includes text editor, compiler, downloader, and real time plotter running in host computer for developing control purpose. Using these hardware and software, simple PD position control is implemented, the results shows the effectiveness of the system.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.3-4
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• 2015

자기공진형 무선전력에 대한 많은 연구가 진행되고 있으며 산업계의 관심 또한 꾸준히 증가하고 있다. 하지만 실제 무선전력을 개발하고 적용하는데 많은 어려움이 있으며 실용화 관점의 개발 가이드 역시 부족한 실정이다. 이에 자기공진형 무선전력을 산업계에 보급하고자 최적 설계 플랫폼에 대해 연구 및 제작하였다. 자기공진형 무선전력 최적 설계 플랫폼은 코일 성능을 예측하는 코일 디자이너, 공진 회로를 구성하기 위한 자기공진형 회로 최적화 모듈, 그리고 완성된 시스템에서 성능을 미리 알 수 있도록 성능 시뮬레이터로 구성되어 있다. 실제 설계, 개발 및 실증까지 가능한 자기공진형 최적 설계 플랫폼에 대해 소개한다.