• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.697-698
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• 2008

This paper deals with finite element characteristic analysis of brushless DC motor according to magnetic property measurement methods. Magnetic property data for non-oriented (NO) electrical steel for electric motors are measured by the Epstein test which is considered as the international standards. Data from Epstein test may result in discrepancy from motor characteristic tests due to innate anisotropic property of NO electrical steel. Finite element analysis were performed for a BLDC motor by various measurement methods such as Epstein test, Ring test and single sheet test (SST), and calculated results were compared with considering anisotropic property conditions.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.305-308
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• 2004

There are ground facility of maintenance in house electric facility of infra maintenance electric home appliances having used multifariousness in house, that use electric energy of common source for equipment. The body of building such as the reinforced concrete construction is structurally united, and the electric resistance is also small. It is possible that those foundations have contacted the ground at large surface area and that it substitutes the building construction body for the earth electrode. This is called "the structure earthing". This method has been defined at electrical facilities technical standards and KS in our country, and it has been used in various quarters practically. However, in our country, there is no example of using the foundation of the house as substitution earth electrode practically, and the means of the evaluation as electrode has not been established either. Then, in this paper, basic research for utilizing foundation of the house as substitution earth electrode is carried out.

• Progress in Superconductivity
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• v.13 no.3
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• pp.139-145
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• 2012

Electric activity of cardiac muscles generates magnetic fields. Magnetocardiography (or MCG) technology, measuring these magnetic signals, can provide useful information for the diagnosis of heart diseases. It is already about 40 years ago that the first measurement of MCG signals was done by D. Cohen using SQUID (superconducting quantum interference device) sensor inside a magnetically shielded room. In the early period of MCG history, bulky point-contact RF-SQUID was used as the magnetic sensor. Thanks to the development of Nb-based Josephson junction technology in mid 1980s and new design of tightly-coupled DC-SQUID, low-noise SQUID sensors could be developed in late 1980s. In around 1990, several groups developed multi-channel MCG systems and started clinical study. However, it is quite recent years that the true usefulness of MCG was verified in clinical practice, for example, in the diagnosis of coronary artery disease. For the practical MCG system, technical elements of MCG system should be optimized in terms of performance, fabrication cost and operation cost. In this review, development history, technical issue, and future development direction of MCG technology are described.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.201-208
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• 2022

As around the world, ground and underground transportation capacity is reaching its limit, centering on urban areas. As urban traffic becomes congested, time and cost are astronomical, and environmental destruction caused by urban pollution is becoming increasingly serious. As a way to solve this problem, the means of flying over the air are in the spotlight as the next generation of future transportation, and the concept of urban air mobility (UAM, Urban Air Mobility) is defined as systematic planning. The development of an electric-powered vertical take-off (eVTOL) aircraft that obtains electric power through a battery using a personal aerial vehicle (PAV) as a means of transportation has accelerated. As the aircraft development of new technology aircraft in the evtol method is actively carried out, the need to prepare systems such as aircraft certification standards, pilot qualification systems, and qualification management is emerging. The Federal Aviation Administration (FAA) and the European Union Aviation Safety Agency (EASA), which lead international standards, announced new special technical conditions and temporary regulations SCVTOL-01, respectively. However, the pilot qualification system for operating the uam aircraft has not yet been clearly announced. Therefore, this paper analyzes the recently announced FAA regulations and EASA regulations to identify differences and directions in perspectives on UAMs and study the existing vertical take-off and landing aircraft (VTOL) pilot qualification system to present directions for qualification classification.

• Proceedings of KOSOMES biannual meeting
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• 2003.05a
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• pp.117-123
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• 2003

It is impossible to apply present standards and test methods because the radiation principle and mechanism of a new marine lantern using light emitting diodes is different from those of the existing marine lantern which uses an incandescent electric lamp. Thus. in this study, we discuss the research and development on the light emitting diodes marine lantern and specifications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2249-2253
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• 2011

This paper analyzed the problems of the Korean output regulation in the relevant band through an analytic comparison of the current trend of each country and their standard values concerning the technical standard of low power u-IT equipments. In connection with the standard value of technical values of each country, which has been proposed in the registration of the appropriate electric wave, the paper aims to propose the standard value that could actually be introduced for suitable low power u-IT installations in Korea. Provided that the Korean standard may be upgraded based on the tolerances of technical standards proposed in this paper, this is expected to be committed to the distribution and advancement of low power u-IT equipments; and further, it is anticipated to be prepared with competitiveness not only in the Korean communications market, but also in the international communications market.

• Electric Engineers Magazine
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• v.228 no.8
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• pp.52-57
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• 2001

Presently the Korean grounding system uses TN system, multi-grounding method with IT independent grounding method. Nevertheless TN system can't exist with TT system in the technological terms. If they coexist, it causes ground-fault circuit not to operate, and brings about different electrical potential rise by customer system. It brings about serious problems for safety. This paper aims for improving method of grounding system based on the technical analysis on instances in foreign countries and Korea. Almost standards and construction manner were apt to be internationalized after WTO/TBT agreement was concluded. The internal grounding systems should meet the international criteria and reliability for safety, and be provided with technologically impeccable standards.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.3
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• pp.305-310
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• 2010

DC electricity feeder system operating in the urban railway is typically a feedback circuit consisted of the contact wire and electric railway vehicle via rail. But stray current is flowed on a structure that is not part of the intended electrical circuit with respect to a given structure. This paper presents comparison analysis of field test cases based on criteria of electrolytic corrosion protection of buried metallic structures adjacent to DC traction systems. As a result of it, we confirmed that measurement methods are different from each other about the same tests. Therefore measurement methods to prevent electrolytic corrosion need to establish electrical facilities standards to be applied domestic.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.5
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• pp.418-426
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• 2020

This study tested the electrical, structural, and thermal safety of LED lighting products, available on the market. Five recessed LED systems, 20 W each, and five fixed LED systems, 25 W each, were selected. Dielectric strength tests, live part electric shock protection tests, and thermal tests were conducted on the LEDs. These were key tests for user safety, according to the specification of the safety criteria for electric products, KC 60598-1, South Korea. In addition, the wiring temperature of UL1007, 60227 IEC 08, and UTP cables, was measured. The results of the study gave an in-depth examination of the safety of LED lighting systems for users.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.214-217
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• 2005

To improve the safety of facilities and human beings when the ground fault occurs, public power utility prescribes the reasonable ground resistances, measures and controls the ground resistance of all the ground electrodes biennially. Concerning the safety of human, there are two safety criteria widely accepted, i.e. the IEEE Std 80-2000 and the IEC 479-1:1994. The IEEE Std 80-2000 is based on a simplified electric shock model usually translated into permissible touch and step voltages. The IEC 479-1:1994 is less specific than IEEE Std 80-2000 for analysis purpose. The IEC 479-1:1994 provides values of permissible body current against electric shock duration. This paper provides a technical study of these two standards to analyze the safety of human beings of ground electrodes developed recently for distribution power system.