• 대한방사선기술학회지:방사선기술과학
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• 제30권4호
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• pp.407-417
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• 2007

과거로부터 사회 경제학적인 문제로 주목을 받고 있는 요통은 노화와 유의한 관계가 있음이 보고되고 있으며, 이러한 노화에 의해 추간판의 여러 형태 조직학적 변화도 이미 여러 연구를 통해 보고되었으나 노화에 따른 추간판의 크기 변화에 대한 연구와 이러한 추간판의 변화가 요통과 관련이 있는지에 대한 연구는 거의 이루어지고 있지 않고 있는 실정이다. 이에 본 연구는 노화에 의한 추간판 변인의 변화를 알아보고, 이런 요인들이 정상 피검자와 요통 환자 사이에 차이가 있는지를 MRI 실계측에 의해 알아보고자 수행하였다. 본 연구는 근골격계 질환이 없는 20대$\sim$60대의 정상 성인 50명과 $20{\sim}60$대 요통 환자 50명을 대상으로 L4-5, L5-S1 추간판의 가로 직경, 세로 직경 그리고 면적을 MRI 영상을 통해 실계측하여 노화에 따른 변화와 정상 피검자와 요통 환자 사이의 차이를 비교하는 방식으로 진행하였다. 본 연구 결과 L4-5와 L5-S1 추간판의 가로 및 세로 직경, 면적은 노화에 의해 의미 있는 증가 경향을 보였으며 정상 피검자에 비해 요통 환자의 추간판 변인들이 큰 것을 확인하였다. 따라서 추간판의 크기 변화는 노화에 의한 자발적인 변화이며, 요통 환자의 추간판 변인 증가를 요통 진단에 참조할 수 있는 자료로 사용할 수 있을 것으로 사료되나, 차후 광범위한 피검자를 대상으로 하는 보다 폭넓고 다각적인 연구가 필요한 것으로 사료된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1353-1355
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• 1995

While the modern society has been highly diversified and civilized, the demand for the safty of a power transmission has been greatly increased. For the underground cable, the performance of the electrical equipments is being improved by developing a new technology, and the reliability of the power supply is being up graded by impressing the diagnostic and monitoring technology of the system. In this paper the aging procedure of O.F and XLPE cables are described, including the diagnostic and monitoring equipments and the future subject.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1439-1443
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• 2011

Bimodal Tram is the new conceptual and environmental-friendly public transportation which adopted series hybrid system. The generator driven by CNG engine supplies the electric power to Battery and traction motor. The generator installed on the vehicle will experience the mechanical vibration and electrical transient variation. Those may cause some defects on the generator which will be the hazardous effects to the vehicle. This paper has investigated the possibility to find out some diagnostic features for the defects of generator through the voltage and current generated from it. Those were analyzed in both time and frequency regions. For the next, more works will be needed to complete the purpose of this paper.

• 동의생리병리학회지
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• 제22권6호
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• pp.1403-1409
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• 2008

The purpose of this study is to develop the systematic process on the discrimination of Sasang constitution with the pulse diagnosis apparatus. The pulse waves were acquired at the right and the left Guan point with 1420 people who were apparently healthy. In order to minimize the effect of aging on the shape of pulse wave, the age groups of 30s, 40s, and 50s were used. Taeum group was the best to classify, Soyang group was the worst. With the same group size, the sensitivity of Soyang group was increased. Input variables were selected with the consideration of the floating-sink ratio, tests of equality of group means, multiple comparison, multicollinearity, and structure matrix. To increase the sensitivity of Soyang, the variables which could tell the difference between Soyang and Soeum were selected.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1834-1835
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• 2011

본 논문에서는 22.9kV급 지중 전력 케이블의 열화에 의한 특성 변화를 분석한다. 케이블이 실제 선로로 포설될 경우 케이블에는 고전압이 흐르게 되고, 이로 인해 열이 발생하게 된다. 이와 같이 발생한 열에 의한 절연체 이상은 케이블 사고로 이어지므로 케이블의 열화 특성 분석은 사고를 미연에 방지하기 위해서 필요하다. 따라서 본 논문에서는 실제 선로에 사용된 후 교체된 케이블의 감쇠 상수를 구하여 열화가 진행된 정도에 따른 감쇠상수의 변화를 분석한다. 이 때, 네트워크분석기의 S-파라미터를 이용하여 감쇠 상수를 구하고, 정상 상태 케이블과 폐 케이블의 감쇠상수를 비교하여 열화에 의한 케이블의 특성을 분석한다.

• 대한의용생체공학회:의공학회지
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• 제30권5호
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• pp.355-361
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• 2009

Mitochondria play a key role in maintaining life by producing ATP and heat. Recent researches have demonstrated that degenerative diseases such as heart failure, obesity/diabetes, cardiovascular disease, and psychiatric diseases are accompanied by mitochondria dysfunction. In this sense, mitochondria medicine considers the significance of mitochondria in human pathology and tries to explain degenerative diseases as a fatal consequence of mitochondria dysfunction. Here, I introduce the fundamentals of mitochondria physiology and present examples showing the relationship between mitochondria dysfunction and chronic complex diseases. Although mitochondria medicine uses a molecular biological approach predominantly, a biomedical engineering approach might play a critical role in unveiling the complexity of mitochondria medicine and in its application to the diagnosis and treatment of chronic diseases. Thus, I also briefly review the prospects of research using biomedical engineering methods.

• 전기학회논문지P
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• 제59권1호
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• pp.40-46
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• 2010

DC link electrolytic capacitors are widely used in various PWM power converter system, such as adjustable speed driver(ASD) or DC/DC converter. Electrolytic capacitors, which is the most of the time affected by aging effect, plays a very important role for the power electronics system quality and reliability. This objective of this paper is to propose a improvement method to detect the rise of equivalent series resistor(ESR) in order to realize the online failure prediction of electrolytic capacitor for DC link of PWM power converter. The ESR detection scheme is based on the determination of the electrolytic capacitor AC losses calculated from voltage/current measurement using AC coupling. Therefore, the preposed online failure prediction method has the merits of easy ESR computation and circuit simplicity compare with BPF method. Simulation results show the veridity of the proposed on-line ESR estimation method.

• 전기학회논문지
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• 제63권2호
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• pp.297-305
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• 2014

Nowadays new water supply projects have been on the decline as the water-power constructions have saturated, which means that the existing power equipment have slowly aged and they require more efforts to maintain the system performance. An effective asset management method of power equipment has become a great necessity from both economical and technical aspects. To be balanced, the asset management should look into all three parts: management, engineering, and information. The purpose of this paper is to study a Risk-Based Maintenance (RBM) matrix method through the deterioration evaluation algorithm for an efficient reliability assessment of oil-immersed power transformers by considering both asset management and technical evaluation. Make use of this result, the equipment will be decided to be replace or repair otherwise on service.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.35-40
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• 1997

As demand of electric power are growing and transmission line limited owing to enlargement of the downtown area The eonfidence of underground transmission cable which shows gradual growth are high. It is found whether insulating ability is good or not. In this paper, The exper iment result is shown that the fall of insulating ability and take preventive measure through the analysis of tans, water content, dielectric breakdown voltage, total acid number, volume resistivity , and gas in the oil in an accordance with the characteristic change of oil used very much for insulating oil of cable.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
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• pp.141-143
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• 2006

Dissolved gas analysis (DGA) is widely used to detect incipient faults in oil-filled electrical equipment. KEPCO make a rule of DGA in 1985. They have been diagnosing power transformer using their DGA criteria. In this paper, we analysis the result of DGA data about transformer in the substation. We try to find out what is cause of an error in DGA diagnosis considering accuracy in extracting gases from mineral oil in transformer. The carbon-monoxide was primary reason of warning in DGA data. We specially consider that aging is a cause of generating of carbon-monoxide in power transformer.