• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1265-1266
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1237-1238
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• 2010

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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• pp.102-105
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• 2002

ADSS(All Dielectirc Self-Supporting) cable installed under high voltage power cable line suffers a variety of environmental influence, rain, wind, snow fall, chemical pollution, salt fog and electrical stress. Its lifetime is required to be at least 20 years with this harsh weathering condition. The electrical stress under high voltage power line gives rise to dry band arcing and tracking, the severest damage, on the outer sheath of cable. Finally tracking might penetrate sheath and cause the break-down of ADSS cable. Tracking resistant sheath material, therefore, should be used to protect the core of ADSS from dry band arcing and to be sure long lifetime. In this work, we discuss various commercial tracking resistant material to investigate the way of track resistance and compare their mechanical, electrical, weathering and tracking properties through serial experiments. We found track resistant material is categorized into two main type : polyethylene with metal hydroxide and polyethylene with reduced carbon black. The Liquid contaminant, Inclined plane Tracking and Erosion test says the time to track of tracking resistant material with metal hydroxide has a little longer time to track in the high applied voltage than that with carbon black, but mechanical and weathering properties were inferior to.

• 한국구조물진단유지관리공학회 논문집
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• 제22권2호
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• pp.1-7
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• 2018

현수교 주 케이블은 케이블 밴드의 볼트 축력에 대한 정기적인 유지 관리가 매우 중요하다. 현수교 케이블 밴드의 볼트 축력은 시간이 경과함에 따라 케이블 소선의 크리프 현상, 볼트의 릴렉세이션, 하중 변동, 케이블 소선의 재배열 등으로 인해 축력 감소 현상이 발생하게 된다. 본 연구에서는 국내 현수 교량(SR대교)의 케이블 밴드가 시간이 경과하면서 발생하는 축력 감소 현상에 대해 그 원인 및 감소량 등에 대한 현장 측정 및 이론적 검토, 안전율 검토, 장기적인 이력 관리 등을 수행하였다. 그 결과, 케이블 밴드 볼트 축력 감소는 주 케이블 소선에 사용된 아연 도금층의 소성 변형에 크게 영향받는 것을 확인하였으며, 이에 대한 이론적 체계 및 장기 이력 관리에 대한 적용성을 확립하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 전기설비
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• pp.127-129
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• 2005

OPGW(Optical Ground Wire) whose demand is increasing worldwide have composite function as optical communication and grounding for preventing transmission line from lightning. While continuous efforts have been made to increase the transmission capacity and speed, the working method to replace the existing ground wire with OPGW under live-line condition is coming to force newly as installation aspects. Particularly, this requirement became more serious in developing country that the electric power supply is not sufficient and power outage is impossible for supply and dead of electric power LS cable Ltd. has developed the new installation method in full live-line condition to solve the confronted problem and to meet the market demand. In this paper, Electric Problems in live-line installation is considered to predict dry-band arcing. This can be used by Makers to predict dry-band arcing in insulating ropes installed on earth wire of power transmission system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.433-435
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• 2004

본 논문에서는 기존의 가공지선(GW, Ground Wire)을 OPGW(Optical Ground Wire)로 교체공사를 할 경우 나타나는 절연로프에서의 건조대 아크현상을 수치적인 모델링를 통하여 해석할 수 있는 프로그램을 제작하고 현장조건을 입력하여 문제점을 판단하고 해결할 수 있는 방안을 제시하고자 한다.

• 대한전자공학회논문지TC
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• 제45권1호
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• pp.27-32
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• 2008

전파가 도달하지 않는 지하 공간에서는 전파를 중계해주는 중계기가 필요하고, 전파를 방사하기 위한 안테나가 필요하다. 지하공간에서 방사 형태에 따라 안테나 방식과 LCX(Leakage Coxial Cable)방식 또는 RCX(Radiax Coaxcial cable)의 두 종류가 있으며, 설치환경 및 주파수 등 용도에 따라 선택이 틀려질 수 있다. 일반적으로 이동통신에서 주로 많이 사용 되고있는 주파수가 비교적 높은(500MHz대역이상)에서는 안테나 방식을 적용하고, FM, T-DMB, 소방무선, 지하철 자가통신망 등 주파수가 낮은 대역(500MHz이하)에서는 LCX방식을 적용하는 것이 효율적이라고 볼수 있다. 중계망의 설계는 자유공간손실, LCX의 결합/전송 손실의 이론 바탕에서 셀 설계를 할 수 있으며, 무엇보다 필드에서의 실측 실험치의 데이터에 의하여 셀 설계가 가장 현실에 적용하기 적합한 방법이라고 할 수 있다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
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• pp.101-104
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• 2001

In this paper, we have analyzed algorithm about physical layer, data link layer and MAC layer of out-of-band specified in the DVS 178 and designed architecture of Out-of-band processor. Out-of-band processor extracts session key information from EMM packet to descramble MPEG-2 TS packet scrambled. Also, analyze EAS Packet including emergency alert information to provide emergency communications such as national emergency. In this paper, we have implemented prototype board for out-of-band processor.

• Structural Monitoring and Maintenance
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• 제9권2호
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• pp.179-200
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• 2022

This paper proposes a data-driven methodology for online early damage identification under changing environmental conditions. The proposed method relies on two data analysis methods: feature-based method and hybrid principal component analysis (PCA) and kernel PCA to separate damage from environmental influences. First, spectral sub-band features, namely, spectral sub-band centroids (SSCs) and log spectral sub-band energies (LSSEs), are proposed as damage-sensitive features to extract damage information from measured structural responses. Second, hybrid modeling by integrating PCA and kernel PCA is performed on the spectral sub-band feature matrix for data normalization to extract both linear and nonlinear features for nonlinear procedure monitoring. After feature normalization, suppressing environmental effects, the control charts (Hotelling T² and SPE statistics) is implemented to novelty detection and distinguish damage in structures. The hybrid PCA-KPCA technique is compared to KPCA by applying support vector machine (SVM) to evaluate the effectiveness of its performance in detecting damage. The proposed method is verified through numerical and full-scale studies (a Bridge Health Monitoring (BHM) Benchmark Problem and a cable-stayed bridge in China). The results demonstrate that the proposed method can detect the structural damage accurately and reduce false alarms by suppressing the effects and interference of environmental variations.

• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.422-429
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• 2008

This paper presents compact low frequency ultra-wide band (UWB) sensor design and study of the partial discharge diagnosis by sensing electromagnetic pulse emitted from the partial discharge source with the newly designed UWB sensor. In this study, we designed a new type of compact low frequency UWB sensor based on microstrip antenna technology to detect both the low frequency and high frequency band of the partial discharge signal. Experiments of offline PD testing on medium voltage (22.9kV) underground cable mention the comparative results with the traditional HFCT as a reference sensor in the laboratory. In the series of comparative tests, the calibration signal injection test provided with the conventional IEC 60270 method and high voltage injection testing are included.