• 전기학회논문지
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• 제65권3호
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• pp.504-510
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• 2016

In general, a fault locator is installed in Sub-Station of AT(Auto-transformer) feeding system to estimate the fault location and to protect the Korean AT feeding system. Since the line impedance characteristic is different to normal 3-phase transmission line, we need particular modification factors, which can be calculated using fault location recording data, to estimate the accurate fault location. Up to recently, forcible ground test has been used to calculate the modification factors of the fault locator. However, large amount of current is occurred when the forcible ground test is performed, and this current affects to adjacent equipments. Therefore, we proposed a novel calculation method of modification factors, arbitrary trip test, using boosting current of the operating electric train. Through several field test, we confirmed that modification factors for fault locator can be easily calculated by using proposed method. Moreover, we verified the accuracy and stability of the proposed calculation method.

• Journal of information and communication convergence engineering
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• 제6권2호
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• pp.172-176
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• 2008

This paper presents a novel feeding structure of the triple-band internal antenna which covers CELLVLAR/DCS/US-PCS bands. The proposed antenna consists of a U-slot patch radiator with a shorting post connected with ground plane and symmetric feeding lines with respective a feeding and shorting posts on both faces of the fixed FR-4 substrate. Through the simulation and experimental results, the proposed antenna is confirmed to have the features of less interference with a human head/body, broad bandwidth, desirable radiation patterns and efficiency for triple-band applications.

• Asian-Australasian Journal of Animal Sciences
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• 제14권2호
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• pp.224-230
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• 2001

This study was conducted to evaluate the extruding effects of corn and wheat on growth performance and fecal digestibility of amino acids in early-weaned pigs. Ground corn and wheat by a hammer mill (3 mm screen in diameter) were extruded at $130{\pm}2^{\circ}C$ with a moist-type extruder ($Matador^{(R)}$). Treatments were: 1) 3 mm ground corn, 2) extruded corn, 3) 3 mm ground wheat, and 4) extruded wheat. A total of 160 pigs (14 d of age and $4.3{\pm}0.74kg$ BW) were allotted with the dietary treatments for a 21-d feeding trial. All diets were mash and contained 30% corn or wheat products. For a digestibility trial, 16 pigs (14-d old and $4.2{\pm}0.32kg$ BW) were employed in individual metabolic crates. There were no differences (p>0.15) in growth performance between corn-fed and wheat-fed groups. Feeding pigs diets containing extruded corn or wheat did not affect ADG (p>0.15) and ADFI (p>0.15), but it improved feed/gain (p<0.01). Also, feeding pigs diets containing extruded corn or wheat had lower true fecal digestibilities of arginine, histidine, isoleucine, lysine and valine (p<.007) in the pigs. In conclusion, our results suggest that extruding corn and wheat had no benefit on the growth of early-weaned pigs.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 추계학술대회
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• pp.55-56
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• 2017

본 논문에서는 동일면 도파관(CPW; coplanar waveguide) 급전 방식을 이용하여 실내 디지털 TV(DTV)용 광대역 루프 안테나를 설계하였다. 제안된 루프 안테나는 정사각형 루프와 중앙 급전점을 연결하는 두 개의 원형 섹터로 구성되며, 아래쪽 원형섹터에 CPW 급전선로가 삽입된 형태이다. CPW 급전선로는 DTV응용을 위해 75옴 포트 임피던스와 정합하도록 설계되었으며, 중간 주파수 대역에서 임피던스 정합을 개선하기 위한 슬롯이 접지면에 추가되었다. 최적화된 안테나를 FR4 기판에 제작하고 특성을 실험한 결과, 전압 정재파비(VSWR; voltage standing wave) < 2인 대역이 463-1,280 MHz으로 DTV 대역에서 동작하는 것을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.166-168
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• 2008

DC feeding system is mainly floating but the rail potential and the leakage current are created because of long parallelism between rails and ground. Rail potential causes electric shock to human and leakage current causes electrolytic corrosion to nearby the buried metals. Therefore the design technologies to reduce, protect and monitor these effects are important recent DC feeding system. Rail potential and leakage current are analysed based on propagation theory that is utilized in order to simulate grounding system. New measurement procedure is proposed based on this analysis in order to more be accurate in result.

• 한국전자파학회논문지
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• 제11권2호
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• pp.217-227
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• 2000

본 논문에서는 유한요소법(FEM. Finite Element Method)을 적용하여 coaxial feeding 구조를 가진 접지면 위에 부착된 직육면체형 세라믹 유전체 안테나를 해석하였다. 제안된 프로그램의 타당성을 검증하기 위하여 시제품을 제작하여 안테나 특성의 설험 값과 본 프로그램의 해석치를 비교하였으며 잘 일치함을 확인할 수 있었다. 이로써 본 유한요소 프로그램을 검증할 수 있었고, coaxial feeding 구조를 가진 접지면 위에 부착된 임의의 3차원 안테나 구조불 해석에도 확장이 가능함을 알 수 있었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.236-241
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• 2007

DC feeding system is mainly floating but the rail potential and the leakage current are created because of long parallelism between rails and ground. Rail potential causes electric shock to human and leakage current causes electrolytic corrosion to nearby the buried metals. Therefore the design technologies to reduce, protect and monitor these effects are important recent DC feeding system. Normally during designing DC feeding system in terms of rail potential and leakage current, there are about 10 parameters. Four design parameters among those is analysed based on propagation theory that is utilized in order to simulate grounding system.

• 전기학회논문지
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• 제66권3호
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• pp.599-604
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• 2017

Nowadays reactance method is being used as a technique for fault location in parallel feeding AC traction power system. However, implementation of this method requires a large number of field tests(ground fault) which is a huge burden on the operators. This paper presents a new estimation technique using quadratic interpolation to reduce number of times for field test and improves the accuracy of fault location. To verify a new technique, we solve AT feeding circuit and model it using PSCAD/EMTDC. Finally this paper conducts a comparative analysis of usefulness between a new technique and real field data.

• Journal of Electrical Engineering and Technology
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• 제11권5호
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• pp.1305-1310
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• 2016

• Asian-Australasian Journal of Animal Sciences
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• 제19권1호
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• pp.91-96
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• 2006

The experiment was conducted to study the effect of choice feeding on growth performance, carcass quality, gastrointestinal development and feed utilization of 22-49 days old broilers. One hundred and forty four 22-day-old broilers were randomly allocated to 3 treatments with 4 replicates per treatment and 12 birds per replicate. Three feeding regimes are complete diet (control), ground corn and protein concentrate (treatment I), and soybean meal and balancer (treatment II). Protein concentrate is the residue part of complete diet without corn, and balancer is the residue part of complete diet without soybean meal. Treatment I and II are designed for the broilers to freely choose the two parts of diet. The results showed that: (1) broilers under choice feeding (treatment I and II) had lower performances compared with the control; (2) gastrointestinal development and the efficiency ratios that broilers converted dietary crude protein and lysine to body weight gain were improved in treatment I (p<0.05); (3) there were no significant differences in the apparent metabolizabilities of dietary dry matter, crude protein and gross energy, and deposition ratios of dietary nitrogen and energy, and carcass quality among three feeding regimes (p>0.05).