• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1254-1256
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• 2001

This paper composes the Electric Railway System with the common grounding based on the 5-port network model. We compare the magnification ratio of harmonic currents according to locations of RC bank(i.e s/s. sp, and pp). It takes a lot of costs to equip the RC-bank at all location. And it is NOT effective that RC-bank is equipped at S/S. Finally, this paper proposes SP as the optimal site of RC-bank aspect reducing harmonic.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.462-464
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• 2005

This paper analyses the transient phenomena against single line to ground fault and lightning surge between Korea and Japan on underground power cable systems. For analysis, find proper earthing resistance of neutral grounding system adopted in Japan. This paper is expected to contribute the establishment of proper protection methods against transients on underground power cable systems.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.319-322
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• 2002

Distance relay is operated in calculating line impedance. It can be worked accurately in overhead line. However, power cables or combined transmission lines need compensation for calculated impedance because cable systems have sheaths, grounding wires and sheath voltage limiters(SVLs) Neuro-fuzzy can be viewed either as a fuzay system, a neural network or fuzzy neural network and it can estimate the location of the fault accurately. In this paper, fault section and fault location can be classified and estimated in neuro- fuzzy inference system and neural network.

• Journal of Aerospace System Engineering
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• v.7 no.2
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• pp.47-54
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• 2013

This paper describes and analyzes the HIRF protection standards of the helicopter category focused on external RF environments. In addition, this paper presents an ideal process of airplane design to accomplish the successful certification. Furthermore, this paper proposes practical recommendations to reduce RF energy on aircraft using specific EMI/EMC techniques such as shielding, grounding and filtering methods. Most of the proposed methods in this paper were key issues during the certification process of KC-100 small airplane which is Korea's first trial aircraft for civil airplane certification.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.3
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• pp.486-491
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• 2011

Since Korea has high accident rate for the electrical shock than other advanced countries, it causes very serious problems. In this paper, a new classification method for analyzing electricity accidents is proposed, which is based on the microscopic view while existing methods have been based at the macroscopic view point. Electrical accidents cases can be mainly divided by three cases, which are from live works, incompleteness of the grounding system and imperfectness of the safety education and public relations. New data format of electrical shocks are proposed in the environment of smart grids.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.44-46
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• 2013

Since vessel traffic service system was introduced domestically in 1993, the incidence of vessel collision and grounding accidents has been diminished dramatically. However, recently the non-fishing boat incidents frequently occur outside boundary of vessel traffic control zone. Owing to this fact, before expanding and establishing 11 VTS centers all over the country by 2023, Korea Coast Guard has a plan to launch the nation's first researches on Mobile VTS Operation System utilizing Korea Coast Guard's patrol ships so as to devise practical countermeasures about those incidents.

• Proceedings of the KIEE Conference
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• summer
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• pp.27-29
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• 2004

Recently, there are many electricity, electronics, and communication equipment which need to earthing in the building. When electric current flows into a certain earthing system in the same building, the potential of other earthing system rises. This potential interference require surface potential of electrods by electrode shape. In this paper basic formula is deduced on the basis of both electrodes surface potential of earth electrode as a source of the potential interference and earth electrode which receive the potential interference. The degree of potential interference as multiple earth electrode is verified the simulated results by means of the simple model in advance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.6
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• pp.1108-1114
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• 2016

The cause of failure in the AT feeding system is divided into grounding, short-circuit of feeding circuit and internal faults of the railway substation. Since the fault current is very high, real-time current is detected and the failure must be immediately removed. In this paper, a new DC offset elimination filter that can remove component to decrease in the form of exponential function using low-pass filter was proposed in order to extract the fundamental wave from distorted fault current. In order to confirm the performance of the proposed filter method, AT feeder system was modelled by simulation tool and simulations were performed under various conditions such as fault location, fault resistance and fault voltage phase angle in case of trolley-rail short-circuit fault. When applying the proposed DC-offset removal method, it can be seen that the phase delay and gain error did not appear.

• KSCI Review
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• v.14 no.1
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• pp.185-196
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• 2006

IIn this paper, we developed e-Leaning system based on open source software. We selected the Moodle that after compared the open source learning management systems. Moodle is APM(Apache, PHP, MySQL) based learning management system(LMS) support SCORM(Sharable Content Object Reference Model), a software package designed to help educators create quality online courses. One of the main advantages of Moodle over other systems is a strong grounding in social constructionist pedagogy. Also we integrated Moodle and legacy systems such as streaming service, webhard service, and short message service. Therefore this research showed that open source based e-Learning system include learning management system is stable and possible.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.9
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• pp.851-855
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• 2005

We investigated the unbalanced characteristics of the superconducting fault current limiters (SFCLs) based on YBCO thin films with a single line-to-ground fault. When a single line-to-ground fault occurred, the short circuit current of a fault phase increased about 6 times of transport currents after the fault onset but was effectively limited to the designed current level within 2 ms by the resistance development of the SFCL. The fault currents of the sound phases almost did not change because of their direct grounding system. The unbalanced rates of a fault phase were distributed from 6.4 to 1.4. It was found that the unbalanced rates of currents were noticeably improved within one cycle after the fault onset. We calculated the zero phase currents for a single line-to-ground fault using the balanced component analysis. The positive sequence resistance was reduced remarkably right after the fault onset but eventually approached the balanced positive resistance component prior to the system fault. This means that the system reaches almost the three-phase balanced state in about 60 ms after the fault onset at the three-phase system.