• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2139-2142
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• 1999

765kV substations which will be the core installation of the bulk power transmission system in Korea for the upcoming $21^{st}$ century, were designed of outdoor full GIS type to minimize required area. As principal equipment, main transformers of 2,000 MVA per bank and 50kA 8,000A gas insulated switchgears of up-to-date technology were adopted in designing substations to transmit bulk power of 10GW. Dual digital protective relay systems and distributed indication and control systems with fiber optic LAN were used.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.340-343
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• 2005

This paper is for studying the feasibility of SFCL application for the interconnection operation of 154kV power systems under 345kV S/S in Korean power system. All Korean 154kV power systems are constructed as loop systems in downtown. However, the present 154kV systems are operated with separated systems around 345kV S/S because of fault current and overload problems. In this study, we investigate the structure and operation of 154kV power system in Seoul and study the feasibility of interconnection operation of 154kV systems under 345kV systmes by applying SFCLs to 154kV bus-tie.

• The Pure and Applied Mathematics
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• v.22 no.2
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• pp.139-144
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• 2015

Abstract. In this paper, we investigate the relationships between the space X and the hyperspace C(X) concerning admissibility and connectedness im kleinen. The following results are obtained: Let X be a Hausdorff continuum, and let A ∈ C(X). (1) If for each open set U containing A there is a continuum K and a neighborhood V of a point of A such that V ⊂ IntK ⊂ K ⊂ U, then C(X) is connected im kleinen. at A. (2) If IntA ≠ ø, then for each open set U containing A there is a continuum K and a neighborhood V of a point of A such that V ⊂ IntK ⊂ K ⊂ U. (3) If X is connected im kleinen. at A, then A is admissible. (4) If A is admissible, then for any open subset U of C(X) containing A, there is an open subset V of X such that A ⊂ V ⊂ ∪U. (5) If for any open subset U of C(X) containing A, there is a subcontinuum K of X such that A ∈ IntK ⊂ K ⊂ U and there is an open subset V of X such that A ⊂ V ⊂ ∪ IntK, then A is admissible.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.627-633
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• 2015

We designed of a LDO regulator with a OVP and UVLO protection function for a PMIC. Proposed LDO regulator circuit consists of a BGR reference circuit, an error amplifier and a power transistor and so on. The proposed LDO regulator is designed for low voltage input power protection. Proposed LDO circuit generated fixed 2.5 V from a supply of 3.3V. It was designed with 3.3 V power supply using a $0.35{\mu}m$ CMOS technology. SPICE simulation results showed that the proposed circuit provides 0.713 mV/V line regulation with output 2.5 V ~ 3.9 V and $8.35{\mu}V/mA$ load regulation with load current 0 mA to 40 mA.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.10
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• pp.239-244
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• 2013

This paper presents a design of the CMOS LDO regulator with a UVLO protection function for a high speed PMIC. Proposed LDO regulator circuit consists of a BGR reference circuit, an error amplifier and a power transistor and so on. UVLO block between the power transistor and the power supply is added for a low input protection function. Also, UVLO block showed normal operation with turn-off voltage of 2.7V and turn-on voltage of 4 V in condition of 5 V power supply. Proposed circuit generated fixed 3.3 V from a supply of 5V. From SPICE simulation results using a $1{\mu}m$ high voltage CMOS technology, simulation results were 5.88 mV/V line regulation and 27.5 uV/mA load regulation with load current 0 mA to 200 mA.

• Bulletin of the Korean Mathematical Society
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• v.36 no.2
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• pp.337-342
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• 1999

M. Cohen and S. Montgomery showed that a Maschke-type theorem for the smash product, which unlike the corresponding result for group actions, does not require any assumptions about the characterstic of the algebra. Our purpose in this paper is a Maschke-type theorem for the graded smash coproduct C⋊kG: let V be a right C⋊kG-comodule and W a C⋊kG-subcomoduleof V which is a C-direct summand of V. Then W is a C⋊kG-direct summand of V. Also this result is equivalent to the following : let V be a graded right C-comodule and W a graded subcomodule of V which has a complement as a C-subcomodule of V. Then W has a graded complement.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.428-431
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• 2009

KPX sets up the voltage standards according to the voltage level to supply a good quality of electricity to customers. Supply voltages are divided into 4 levels - 345kV, 154kV, 22.9kV, and distribution voltage consisting of 110, 220 and 380V. In this research, we examine the optimal voltage operating level focused on 154kV system that mostly affects electricity quality, through analysing the system demand.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1773-1779
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• 2015

Insulation coordination is a key problem in UHVDC systems in terms of safety and cost. Although high-voltage ±1100kV UHVDC projects are being planned in China, the characteristics and key points of high-voltage systems have not yet been analyzed. This study aims to improve the safe, effective operation of these high-voltage power transmission systems. First, we analyzed two typical insulation coordination schemes used in ±800kV UHVDC systems in China. Next, we used the two typical ±800kV insulation coordination schemes as a reference to analyze the ±1100kV UHVDC system. Finally, we compared these schemes and proposed an effective insulation coordination solution, as well as developing principles for ±1100kV UHVDC systems. Our findings indicate that the points enduring the highest voltage in the system should be protected separately by special arresters. Our analysis of the insulation coordination of ±800kV and ±1100kV UHVDC systems concluded that, in ±1100kV UHVDC systems, the main goal of insulation coordination is to lower the insulation level of points enduring the highest voltage. However, in a ±800kV UHVDC system, the main goal is to reduce the cost of manufacture for arresters, as well as the space occupation in the valve hall, with an acceptable insulation level.

• International Journal of Industrial Entomology and Biomaterials
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• v.9 no.2
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• pp.217-223
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• 2004

A cathepsin L-like cysteine protease, v-cath, encoded by the baculovirus has been shown to playa role in host liquefaction. We have identified a v-cath gene in the silkworm virus, Bombyx mori nuclear polyhedrosis virus (BmNPV) K1 strain. The 969 bp v-cath has an open reading frame of 323 amino acids. A putative cleavage site and catalytic sites were conserved in BmNPV-K1 v-cath. The predicted three-dimensional structure of BmNPV-K1 v-cath revealed that the overall fold of BmNPV-K1 v-cath is similar to that of other proteases of the papain family. The deduced amino acid sequence of BmNPV-K1 v-cath showed 98% and 97% protein sequence identity to BmNPV T3 strain and to Autographa californica nuclear polyhedrosis virus, respectively. The BmNPV-K1 v-cath differed at 4 amino acid positions from BmNPV T3. The v-cath gene in BmNPV-K1 genome is located on the EcoRV 6 kb and XhoI 9 kb fragments. Northern hybridization analysis of BmNPV K1 v-cath gene revealed that it is expressed late in infection.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.278-279
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• 2015

한전 계통의 수도권 부하 밀집과 지중화 선로 증가로 인해 수도권 345kV 계통 과전압이 큰 문제가 되고 있다. 조상설비 투입 후에도 과전압이 문제가 되는 경우, 과전압 해소를 위한 다른 방안이 필요하다. 본 논문에서는 345kV 과전압 해소를 위한 345kV-154kV 변압기 탭조절 방안을 검토하였다. 효율적인 과전압 해소를 위해 탭 감도를 이용하여 탭 조절을 수행하였다. 또한 일반적인 경우 345kV-154kV 변압기의 2차측 전압을 올리면 1차측 전압이 떨어지지만 본 논문에서는 그렇지 않은 경우를 찾아내고 해당 원인을 분석하였다. 모의를 위한 데이터는 2014년 한전 과전압 모의 데이터를 사용하였다.