• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1745-1747
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• 2004

In order to anticipate gradual increase of fault current in electric power systems, current limiting technology and current limiting device has been investigated for a long time. But the commercial use of current limiting device was delayed due to the lack of effective method to insert impedance to the elective power systems without loss and surplus defects. However, novel current limiting device, which use superconducting materials, was considered as a dream technology to be applied in a distribution and transmission lines. LG Industrial systems and KERPI started to investigate resistive type superconducting fault current limiters in order to develop 154kV fault current limiters and this year, we succeed to test 3 phase 6.6kV/200A fault current limiters. Based on these achievements, 24kV superconducting fault current limiters will be realized withing 3 years which could be tested in a real fields. In this paper, the developments of fault current limiting module which use YBCO thin films, cryogenic systems, the structure and construction of 3 phase fault current limiters and finally the test results of 6.6kV superconducting fault current limiters will be introduced.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.720-723
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• 2003

Electric stimulation of teeth is used for assessing pulp vitality. Because of very high and wide range of impedance of the enamel, electric pulp testers use high voltage, high output impedance and alternative current source. Most pulp testers use voltage stimulation method and their stimulating threshold levels significantly depend on each individual. Therefore, a constant current stimulator is necessary to minimize the effect of wide variation in enamel thickness. In this study, we constructed a constant current source type of pulp tester with the maximum current of 150 uA.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.299-304
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• 2003

This paper proposes an algorithm to estimate the screw torque from parameters of induction motor and current of DC motor without strain gage and torque cell. The parameters of friction torque search for damping ratio and electromotive force constant use the motor torque and angula speed signals be generated in the induction motor, make use of oscilloscope and stroboscope for precise measured of experimental data, measured physical parameters through experimental. In addition the screw torque estimated use of measured current signals from induction moor. The results, theory and simulation recognized well coincidence.

• 대한통합의학회지
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• 제10권2호
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• pp.155-167
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• 2022

Purpose : Accumulation of accurate data regarding the use and adequacy of subsidies is important to provide optimal development rehabilitation services. However, no reports have discussed the status regarding the use and adequacy of subsidies available for motor development rehabilitation as a part of development rehabilitation services in children and adolescents with cerebral palsy. In this study, we investigated the current use and subsidy adequacy of motor development rehabilitation as an essential part of development rehabilitation services in children and adolescents with cerebral palsy. Methods : The study included parents of children and adolescents with cerebral palsy, who underwent motor development rehabilitation of development rehabilitation services (n=148). The participants were administered a questionnaire to investigate the current use and subsidy adequacy of the motor development rehabilitation part of development rehabilitation services. Results : Most respondents indicated that 310,000-410,000 /month was an appropriate subsidy and agreed that the subsidy should be extended to adults with cerebral palsy. We observed a significant difference in the appropriate subsidy based on age groups (p=.029), as well as type of development rehabilitation service most needed (p=.005) and whether or not agree to extend the subsidy to adults according to gross motor function classification system level (p=.015). There were significant relations of appropriate subsidy (p<.001) and appropriateness of copay (p=.004) according to degree of transportation cost burden. Moreover, there were significant relations of appropriateness of current subsidy (p=.015) and appropriate subsidy (p<.001) according to degree of inconvenience of using transportation. Conclusion : This study highlights the need to increase subsidies for motor development rehabilitation of development rehabilitation services and that the subsidy should be determined based on the burden of transportation costs and the inconvenience of using transportation. Development rehabilitation service for adults with cerebral palsy should also be supported.

• 천문학회지
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• 제38권2호
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• pp.117-120
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• 2005

Current instrumentation activities and the open user status of Okayama Astrophysical Observatory (OAO) are reviewed. There are two telescopes in operation and one telescope under reforming at OAO. The 188cm telescope is provided for open use for more than 200 nights in a year. The typical over-subscription rate of observation proposals for the 188cm telescope is ${\~}$ 1.5 - 2. The 50cm telescope is dedicated to $\gamma$-ray burst optical follow-up observation and is operated in collaboration with Tokyo Institute of Technology. The 91cm telescope will become a new very wide field near-infrared camera in two years. The high-dispersion echelle spectrograph (HIDES) is the current primary instrument for the open use of the 188cm telescope. Two new instruments, an infrared multi-purpose camera (ISLE) and an optical low-dispersion spectrograph (KOOLS), are now under development. They will be open as common use instruments in 2006.

• 대한전기학회논문지:전력기술부문A
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• 제48권3호
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• pp.184-189
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• 1999

In this paper, we develope a diagnosis device for ZnO arrester by detecting the leakage current in service. To diagnose the deterioration of ZnO arrester, the device detects the total leakage current which flows between an arrester and ground, and analyzes the resistive current(third harmonic current) which is an indicator of deterioration of ZnO arrester. We use the optical cable which can transfer a detected data without a noise, also use a microprocessor for a data storage, processing, and trend analysis. Experiment are executed to verify its performance in laboratory and the results show that the diagnosis device exactly detects the total leakage current and the resistive current, so it can diagnose the deterioration of ZnO arrester. Also the leakage current of ZnO arrester is detected using the developed diagnostic device in field, these results are presented.

• 대한전기학회논문지:전력기술부문A
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• 제51권5호
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• pp.225-231
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• 2002

Many standards have Published for calculating of current carrying capacity for bare overhead conductors. Although these standards use the same basic heat balance concept, they use different approaches to calculate current carrying capacity, This paper looks at the four approaches used to calculate individual heat balance terms, at the overall impact of these terms on the current carrying capacity And this paper is proposed to the selection of proper standard and AC resistance within a country conditions for calculating the current carrying capacity of bare overhead conductors. So current carrying capacities are Proposed to some of conductors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.544-547
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• 1989

The introduction of resonant link inverters has allowed the use of much higher switching frequencies in induction motor current regulators. The resonant link inverter,however, requries the use of discrete time switching strategies. This type of controller,while giving the best possible performance, is difficult to implement, since motor parameters must be calculated or measured. The delta modulated current regurator (DMCR) has been introduced as a controller without additional state feedback. A discrete pulse modulated current regulator which controls load current is introduced in the paper.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.609-611
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• 2008

Eddy current is usually generated in material with high conductivity by time-varying source such as AC current and also is induced in the moving source with relative velocity. The contactless magnetic brakes make use of the braking force from the eddy current generated by moving source and currently used for the secondary brakes of heavy trucks, buses and rail vehicles. This study aims to design the magnetization pattern of a permanent magnet type eddy current brake system to maximize the braking force. The analysis of the brake system is based on the two-dimensional finite element analysis. We use the sequential linear programming as the optimizer and the adjoint variable method for the sensitivity analysis.

• 대한기계학회논문집A
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• 제33권7호
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• pp.658-663
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• 2009

Eddy current is usually generated in the material with high conductivity by time-varying source such as AC current and also is induced by the moving source with relative velocity. The contactless magnetic brake makes use of the braking force from the eddy current generated by the moving source and currently used for the secondary brakes of heavy trucks, buses and rail vehicles. This study aims to design the magnetization pattern of the eddy current brake system of a permanent magnet type where the design aim is to maximize the braking force. The analysis of brake systems is based on the two-dimensional finite element analysis. We use the sequential linear programming as the optimizer and the adjoint variable method is applied for the sensitivity analysis.