• Electrical & Electronic Materials
• /
• v.10 no.3
• /
• pp.247-254
• /
• 1997

Internal voids in insulators give rise to partial discharge, which causes a local breakdown and even entire insulation breakdown. Recently, the necessity of establishing the way to diagnose the aging of insulation materials and to predict of insulation breakdown become important. The purpose of our work are to investigate the treeing phenomena with an artificial needle shaped void by the charge of discharge and acoustic emission pulse in each phase angle area at the same time. We analyzed the .PHI.-QA-t pattern and .PHI.-AEA-t pattern using statistic operators such as pulse magnitude, pulse number, skewness, kurtosis. Therefore, the relation between the charge of discharge and acoustic emission pulse will be helpful to predict the breakdown just before the breakdown occur.

• Proceedings of the KIEE Conference
• /
• 2001.07c
• /
• pp.1616-1618
• /
• 2001

In recent the on-line partial discharge (PD) measurement using sensors, such as EMC, SSC, RTD and RFCT, as an indicator of stator winding insulation condition has been developed. RFCT sensor was placed arounding a grounding lead of surge capacitor to detecting PD. Trend of PD magnitude/phase angle/pulse number over time are useful parameter to diagnosis aging state. We have developed Radio Frequency Current Transformer(RFCT) sensor which is suitable for PD diagnostic measurement in 6.6kV rotating machines. In this paper, we describe the characteristics of RFCT sensor, such as frequency and PD magnitude using 6.6 kV model stator winding in Lab.

• Proceedings of the KIEE Conference
• /
• 1996.07c
• /
• pp.1781-1783
• /
• 1996

Recently, the necessity of establishing the way to diagnose the aging of insulation materials and to predict of insulation breakdown become important. The purpose of our work are to investigate the treeing phenomena with a artificial needle shape void by the charge of partial discharge and acoustic emission pulse in each phase angle area at the same time. We have analyzed the ${\Phi}-Q-n$ pattern and the insulation diagnosis of the samples using statistic operators such as charge magnitude and A.E pulse factor, skweness, kurtosis, G,C. Therefore, the relation between the charge of partial discharge and A.E pulse will be helpful and efficient to predict the breakdown just before the breakdown occure.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1979-1980
• /
• 2008

본 논문은 심혈관질환을 예방하기 위한 심박변이도 검사(HRV), 압맥파 검사(PTG), 용적맥파 검사(SDPTG), 사지혈압 검사(BPD), 맥파전달속도 검사(PWV)를 통해 심혈관의 상태를 분석하고 질병을 예방하는데 도움이 될 수 있도록 측정하고 진단 할 수 있는 심혈관 질환에 대한 통합 진단 시스템을 개발하였다. 본 논문에서 개발된 진단 시스템을 통해서 나오는 결과에 대한 소개하였다.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.2058-2059
• /
• 2008

한전 배전계통에서 적용되고 있는 가공설비 열화진단 장비의 특성 및 진단사례를 고찰하고, 측정 결과의 신뢰도 향상 방안을 제시하였다. 본 논문에서 제시한 열화설비 진단기법 및 신뢰도 향상 방안은 연구개발 과제로 채택되어 진행예정이며, 향후 실험실 모의시험 및 실증 시험을 통해 제시된 이론을 검증하고 체계화 하고자 한다.

• Journal of Korea Multimedia Society
• /
• v.18 no.7
• /
• pp.864-872
• /
• 2015

The purpose of this study is to design the algorithm, Predictive Service Component - PSC, for forecasting and judging obsolescence of solar system that is implemented based on the micro-inverter. PSC proposed in this study is suitable for monitoring of distributed power generation systems. It provides a diagnosis functionality to detect failures and anomaly events. It also can determine the aging of PV systems. The conclusion of this study shows the research and development of this kind of integrated system using PSC will be needed more and varied in the near future.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2011.11a
• /
• pp.409-412
• /
• 2011

최근, 전력설비의 열화진단 및 안전검사에 있어 편의성과 활용성의 측면에서 자외선 카메라가 많은 관심을 받고 있다. 자외선 카메라는 전력설비의 코로나 방전에 의한 자외선 검출을 응용한 기기로서 열화지점과 열화정도를 이미지 형태로 직관적으로 나타낼 수 있다. 따라서 전력설비의 정확한 열화진단을 위해서는 코로나 방전에 대한 전기적 특성과 자외선 특성에 대한 이해가 중요하다. 본 논문에서는 전력설비의 열화진단을 위한 코로나 방전을 모의하고, 그에 따른 자외선 이미지와 전기적 특성에 관해 연구하였다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 1995.10a
• /
• pp.85-95
• /
• 1995

This paper describes a diagnosis of transformer by ultrasonic signal due to partial discharge. The ultrasonic signal can be measured when partial discharge is generated in a real transformer. The trend of partial discharge in transformer was estimated by counting the number of ultrasonic signals until insulation paper in the point-to-plane electrode is destroyed. The number of ultrasonic signals is closely related to the number of the electrical signals by partial discharge. The trend of the ultrasonic signal number could easily be distinguished by taking moving average.

• Journal of Periodontal and Implant Science
• /
• v.38 no.2
• /
• pp.215-224
• /
• 2008

Purpose: These case reports show the orthodontic treatment of lower anterior incisors with gingival recession. Materials and Methods: Three cases were treated by an orthodontist and a periodontist. Each case had lingually tilted lower anterior incisors, anterior crossbite and skeletal Cl III pattern. Results: A variety of etiological factors were thought to cause gingival recession: aging, oral hygiene, tooth malpositioning, occlusal trauma. Conclusion: Due to the interaction among many possible contributing factors, it is difficult to predict whether further gingival recession may occur at a given site. The position and the movement of the lower anterior incisors with gingival recession are important factors in diagnosis and orthodontic treatment planning.

• Annals of Clinical Neurophysiology
• /
• v.16 no.1
• /
• pp.1-7
• /
• 2014

Iron is an important element for brain oxygen transport, myelination, DNA synthesis and neurotransmission. However, excessive iron can generate reactive oxygen species and contribute neurotoxicity. Although brain iron deposition is the natural process with normal aging, excessive iron accumulation is also observed in various neurological disorders such as neurodegeneration with brain iron accumulation, Parkinson's disease, Alzheimer's disease, multiple sclerosis, Friedreich ataxia, and others. Magnetic resonance image (MRI) is a useful method for detecting iron deposits in the brain. It can be a powerful tool for diagnosis and monitoring, while furthering our understanding of the role of iron in the pathophysiology of a disease. In this review, we will introduce the mechanism of iron toxicity and the basics of several iron-related MRI techniques. Also, we will summarize the previous results concerning the clinical application of such MR imagings in various neurological disorders.