• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.892-899
• /
• 2009

This paper describes the design and fabrication of a soil resistivity measurement system using 9 auxiliary electrodes; 6 potential-, a reference-, a current-, and a ground- electrode. The measurement system is composed of a current source (300 [Vrms], 5 [A], Sine-wave, 45 $\sim$ 500 [Hz]), a data acquisition (400 [kS/s], 16 bit, 16 Ch.), and an operating program based on a graphical software of National Instrument Co. The proposed system is convenient for choosing the position of electrodes because the soil resistivity is calculated having no concern with the length and the spacing between electrodes.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.912-918
• /
• 2009

In this paper, we carried out a comparative analysis of partial discharge(PD) patterns caused by deterioration of cast-resin and oil insulation systems. Various electrode systems were fabricated such as needle-needle, needle-plane and plane-plane to simulate defects that may exist in the insulation system of transformers. A low-noise amplifier which has a gain of 40 dB and a frequency bandwidth of 500 kHz $\sim$ 30 MHz (-3 dB) was designed to detect small PD signals. From the analysis of acquired PD signals, we could find that a unique PD pattern is formed according to types of defect. These data will be applied usefully to diagnose insulation condition of transformers.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.1977-1983
• /
• 2009

This paper described partial discharge(PD) patterns depending on types of insulation defects in CNCO-W cable(Concentric Neutral Closs-linked Polyethylene Insulated Polyolefin-Water Proof Sheathed Power Cable). The PD measurement system consists of a coupling network, a detection impedance, and a low noise amplifier. A 16 bit, 250 MS/s data acquisition system was used to analyze PD patterns. To simulate insulation defects in a power cable, a needle with the curvature radius of $10{\mu}m$ was inserted into the insulation part. We measured phase ($\Phi$), magnitude (q), and counts (n) of PD pulse for the defects, and classified PD patterns using the PRPD (phase Resolved Partial Discharge) method. From the analysis of acquired PD signals, we could find that a unique PD pattern is formed according to the types of defect.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2008년도 추계학술대회 논문집
• /
• pp.297-300
• /
• 2008

This paper described a New-Concept lightning warning system (LWS) which can measure electric field intensity on the ground level by an electric field mill (EFM) and calculate the lighting location by radiated electro-magnetic waveform. The EFM measures electric field up to 20[kV/m] with the sensitivity of 0.15[V/kV/m] and frequency bandwidth of the loop antenna was ranges from 5.2[kHz] to 1.71[MHz]. The LWS provides data on the movements of thunderclouds and the possibility of lightning return stroke.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
• /
• pp.97-98
• /
• 2006

High current behaviors of extended drain n-type metal-oxide-semiconductor field effects transistor (EDNMOS) with double polarity source (DPS) for electrostatic discharge (ESD) protection are analyzed. Simulation based contour analyses reveal that combination of bipolar junction transistor operation and deep electron channeling induced by high electron injection gives rise to the second on-state. Therefore, the deep electron channel formation needs to be prevented in order to realize stable and robust ESD protection performance. Based on our analyses, general methodology to avoid the double snapback and to realize stable ESD protection is to be discussed.

• 한국초전도ㆍ저온공학회논문지
• /
• 제7권3호
• /
• pp.21-28
• /
• 2005

Superconducting synchronous motors and generators have the field coil composed of superconductor with almost zero resistance at superconducting state. Therefore, copper loss at the conventional field coil is eliminated and the superconducting machine gets higher efficiency. The armature coil of the superconducting machine is composed of copper wire and supported by non-magnetic material such as FRP (Fiber Reinforced Plastic) This paper contains the design Procedure of a 1MW superconducting synchronous motor using high-temperature superconductor only for the field coil. Especially, the armature coil is designed by water-cooling in order to dissipate Joule heat easily. Moreover, 3-dimensional electromagnetic design is conducted to get a proper design result and reduce design errors from 2-dimensional approach.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2018년도 춘계학술대회
• /
• pp.290-291
• /
• 2018

최근 해상교통량이 증가하고 연안 항해에 대한 관제 필요성이 요구되면서 선박 교통 관제구역이 점차 확대되는 추세이다. 이러한 관제구역의 확대는 관제사의 업무 부하를 초래하며, 이로 인해 교통 혼잡 시간대와 같이 교통량이 급증하는 경우 관제사가 위험 상황을 인지하지 못하는 상황도 발생하게 된다. 이러한 배경에서 본 논문에서는 관제 업무의 지원을 위해 이상 거동 선박을 자동으로 식별하는 방법을 제안하고자 한다. 제안하는 방법은 기계학습 기술을 기반으로 관제구역 내의 통항 패턴을 모델링하고, 이를 통해 이상 거동 선박을 식별하는 방법으로, 대상 항만의 누적된 AIS 데이터를 이용하여 모델을 학습하며, 실제 항적 및 시뮬레이션 데이터를 이용한 실험을 통해 선박교통관제시스템에의 활용 가능성을 고찰한다.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2004년도 춘계 학술대회지
• /
• pp.144-145
• /
• 2004

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2004년도 춘계 학술대회지
• /
• pp.240-241
• /
• 2004

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2004년도 춘계 학술대회지
• /
• pp.150-151
• /
• 2004