• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1761-1763
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• 1997

Because of internal voids in insulators give rise to partial discharge (PD), which cause local breakdown and even entire insulation breakdown. Treeing due to PD is one of the main causes of breakdown of the insulating materials and reduction of the insulation life. Therefore the necessity for establishing a method to diagnose the aging of insulation materials and to predict the breakdown of insulation has become important. From this viewpoint, our studies diagnose insulation degradation using the method of computer sensing system, which has the advantages of PD and acoustic emission (AE) sensing system. To use advantages of these two methods can be used effectively to search for treeing location and PD in some materials. In analysis method of degradation, We analyzed the PD pulse and AE pulses by regression analysis, compared to these obtained the correlation coefficient and determination coefficient by T-distribution and saw that PD and AE pulses show a similar pattern on the whole. This is in agreement with the results of the research by Yoshimura and Fujita.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.1
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• pp.39-45
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• 1999

Because of internal voids in insulators give rise to partial discharge(PD), which cause local breakdown and even entire insulation breakdown. Treeing due to PD is one of the main causes of breakdown of the insulating materials and nrluction of the insulation life. 1berefore the necessity for establishing a rrethod to diagnose the aging of insulation materials and to predict the breakdown of insulation has becorne irrportant. From this viewpoint, our studies diagnose insulation degradation using the rrethod of computer sensing system, which has PD and acoustic emission(AE) sensing system. To use advantages of these two methods can be used effectiveiy to search for treeing location and PD in sorre materials. In analysis rrethod of degradation, we analyzed the PD and AE pulses by regression analysis, corrpared to these obtained the correlation coefficient and retermination coefficient by T-distribution and saw that PD and AE pulses show a similar pattern on the whole. This has a similar teIlrency to the results of the research by Yoshimura and Fujita.Fujita.

• Journal of Chest Surgery
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• v.26 no.4
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• pp.329-332
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• 1993

Breakdown of the normal protective function of the larynx, either through primary or neurologic cause, leads to chronic aspiration, recurrent pneumonitis and possibly death. Lindemann`s tracheoesophageal diversion has three main advantages; first, it eliminates intractable aspiration in all patients who underwent the procedure, second, it preserves larynx, and third, if the underlying neurologic condition is recorved, the procedure can be reversed. We had performed tracheoesophageal diversion in two cases of intractable aspiration pneumonia patients. The postoperative courses were uneventful and they were receiving oral alimentation on the 22th and 9th postoperative days respectively, and could be discharged on 43th and 20th postoperative days respectively.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.511-512
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• 2011

본 논문에서는 154kV 지중송전선로의 기중종단접속함 (EB-A)에서 발생한 절연파괴 고장을 분석하여 정확한 원인을 규명하고자 한다. 케이블 결함은 제조 공정에서 철저히 걸러내도록 조치하고 케이블 공장 출하시 시험을 통해 점검하고 있어, 고장은 케이블 자체 보다 현장에서 시공하는 접속함에서 발생할 우려가 매우 크다. 따라서 접속함 시공은 케이블의 안정적인 운전을 위해 매우 중요한 공정으로 접속작업 후 성능이 케이블과 동등 이상의 특성을 유지하도록 하여야 한다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.513-514
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• 2011

본 논문에서는 154kV 지중송전선로의 관로내 XLPE 케이블에서 발생하는 절연파괴 고장원인을 분석하였다. 일반적으로 케이블은 제조공정 과정에서 결함을 철저히 걸러내도록 조치하고 공장 출하시 시험을 통해 점거하고 있어, 케이블 자체고장은 현장에서 시공하는 접속함에 비해 매우 작지만 드물게 발생하고 있다. 케이블 자체에서 고장 발생시 고장원인 파악을 위해 제조 품질, 시공과정 등을 체계적으로 분석하고 검토하여 케이블 생산, 시공현장 품질저하 및 관리소홀 등으로 인한 케이블 고장을 최소화하고자 한다.

• Proceedings of the KIEE Conference
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• summer
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• pp.480-482
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• 2004

This paper presents a study on the NGR problem for harmonic in distribution systems. Overheating of NGR (Neutral Ground reactor), by neutral current in distribution system, is important cause of transformer breakdown of substation. Countermeasures about zero-sequence component harmonic in neutral line are required.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.41.5-41
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• 2002

This paper presents a feature extraction algorithm for vision-based micromanipulation. In order to guarantee of the accurate micromanipulation, most of micromanipulation systems use vision sensor. Vision data from an optical microscope or high magnification lens have vast information, however, characteristics of micro image such as emphasized contour, texture, and noise are make it difficult to apply macro image processing algorithms to micro image. Grasping points extraction is very important task in micromanipulation because inaccurate grasping points can cause breakdown of micro gripper or miss of micro objects. To solve those problems and extract grasping points for micromanipulation...

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.255-261
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• 2007

In this paper we introduce the method, procedure and result of RAM prediction for interlocking system which is applied for AREX signaling system. For RAM prediction, we breakdown the interlocking system to the LRU level and select the LRUs of which failure can cause the service delay. The prediction of reliability is based on the Reliability Block Diagram which is the functional diagram composed of selected LRUs and finally, the availability of interlocking system is estimated from the combination of reliability and maintainability.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1999.11a
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• pp.168-171
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• 1999

This paper describes the influence of conducting particle within the coaxial cylindrical electrodes gap under alternating voltage condition investigated using charge simulation method. If the conducting particles precent in the gas insulated system, they can cause decrement of breakdown voltage. Thus, three dimensions computations of electric fields and electrostatic forces have been carried out according to particle location. The results show a good agreement with those of outside country, which can offer a practical reference on the insulation design of domestic GIS.

• Journal of Power System Engineering
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• v.14 no.1
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• pp.5-10
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• 2010

Both the accuracy and stability of the clock get from the GPS receiver are considered in the range of pps. And we verified the system clock stability of a micro-controller system using the pps pulse supplied by the GPS receiver. In complex system of digital processing, the rack of precise timing signal may cause the serious problem or breakdown accident. To get rid of these undesirable problems, we introduced VCXO circuit to a micro-controller system to preserve high accurate clock stability.