• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.772-774
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• 2000

The objective of a cathodic protection system (CP) is to protect the buried metallic structure against the corrosion caused by chemical reaction between the buried structure and the surrounding medium, such as soil. This paper presents a boundary element application to determine the optimal impressed current densities in a cathodic protection system. The potential within the electrolyte is described by the Laplace's equation with nonlinear boundary conditions which are enforced based on experimentally determined electrochemical polarization curves. The optimal impressed current densities are determined in order to minimize the power supply for protection. The solution is obtained by using the conjugate gradient method in which the governing equations and the protecting conditions are taken into account by the penalty function method. Numerical example are presented to demonstrate the practical applicability of the proposed method.

• 정보와 통신
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• 제28권12호
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• pp.50-60
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• 2011

Visible light communication(VLC) is one type of short-range, optical, and wireless communication system utilizing light emitting diode(LED) and laser diode(LD) as optical source. In a VLC system, visible light is used as a transmission medium and used to illuminate. Using VLC has a lot of advantages: it is harmless to human body; it transmits with high power, and it has excellent security, a high data rate, and a license free frequency band. With such a unique blend of communication and illumination in one system, the most common application would be an indoor environment. We aim at reviewing key issues in VLC network such as : FOV(field of view), priority MAC, cooperative MAC, link switching, LED-ID technique, cell site diversity, and link recovery.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.467-469
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• 2003

IEC(International Electrotechnical Commission) 62271-100 has been adopted for the design test of circuit breaker which is used as the main protecting device of power system. But, it is also necessary to separately receive the testing certificate in accordance with ANSI/IEEE standard for getting into the american market. Up to now, several domestic companies have completed the ANSI/IEEE testing in medium circuit breaker of distribution system, but they recently started the ANSI/IEEE testing in ultra high-voltage class of transmission and substation system. This paper introduces the testing techniques and its results for the making and breaking performance of 145kV, 40kA $SF_6$ gas circuit breaker which was firstly performed in KERI(Korea Electrotechnology Institute) by the ANSI/IEEE standard.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2004년도 추계학술대회
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• pp.47-51
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• 2004

Facility layout for enterprise's competitive power strengthening and construction of offensive manufacture line and direction presentation for design of production management system that is new by operation improvement according to S company. In enterprise in JIT(Just in Time) system of leading persons affecting in productions among a lot of habitat factor analyze. It is that through equipment Layout among those factors enterprise my problem improve and serves enterprise's absolute ability cultivation. Even if it is JIT production main point that affect to apply the modular production to productive system among at equipment Layout, lot size, bottleneck session etc. worker's multi-function anger, change of demand factor and productive capacity add. 'S' Through enterprise's example, I wish to establish Korean medium and small enterprises' manufacturing industry style equipment Layout model by taken place effect interpretation.

• World Technopolis Review
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• 제1권2호
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• pp.118-128
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• 2012

This paper suggests policy implications for Daedeok Innopolis (DI) in Daejeon by comparing the development and problems of DI with the San Diego biotechnology cluster. DI has strengthened its capabilities for technology commercialization and business activities after having created and managed by the Korean central government. While DI has been successful in increasing the number of institutes, researchers, research activities, however, its dynamism is not rigorous enough to be a regional innovative system. San Diego's scientific and entrepreneurial community shows the importance of formulating social and spatial contexts for mutual interactions and engagements. In San Diego, UCSD and networking organizations, especially CONNECT, are central in promoting interactions and communications between regional constituents including entrepreneurs, academics and local governments. The mechanisms of San Diego biotechnology imply that DI should provide more attention to designing and developing social and geographical space that can unleash the creative power of social interactions. To build an innovative regional system, DI needs to renovate its space, public-private relationship and networking platforms.

• Corrosion Science and Technology
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• 제4권4호
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• pp.140-146
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• 2005

Fossil fired power plant produces the electric energy by using a thermal energy by the combustion of fossil fuels as like oil, gas and coal. The exhausted flue gas by the combustion of oil etc. contains usually many contaminated species, and especially sulfur-content has been controlled strictly and then FGD (Flue Gas Desulfurization) facility should be installed in every fossil fired power plant. To minimize the content of contaminations in final exhaust gas, high corrosive environment including sulfuric acid (it was formed during the process which $SO_2$ gas combined with $Mg(OH)_2$ solution) can be formed in cooling zone of FGD facility and severe corrosion damage is reported in this zone. These conditions are formed when duct materials are immersed in fluid that flows on the duct floors or when exhausted gas is condensed into thin layered medium and contacts with materials of the duct walls and roofs. These environments make troublesome corrosion and air pollution problems that are occurred from the leakage of those ducts. The frequent shut down and repairing works of the FGD systems also demand costs and low efficiencies of those facilities. In general, high corrosion resistant materials have been used to solve this problem. However, corrosion problems have severely occurred in a cooling zone even though high corrosion resistant materials were used. In this work, a new technology has been proposed to solve the corrosion problem in the cooling zone of FGD facility. This electrochemical protection system contains cathodic protection method and protection by coating film, and remote monitoring-control system.

• 한국ITS학회 논문지
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• 제11권5호
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• pp.1-6
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• 2012

현대의 도시교차로는 과거와 달리 날로 이용량과 시설규모가 증가하여 대형화하고 있다. 이에 따라 지역적 정전이나 광역적 정전사태가 발생하는 경우 교통상황은 걷잡을 수 없는 혼잡상황에 직면하게 된다. 최근에는 전력수요예측 오류로 인한 대규모 도시정전사태가 발생한 사례가 있으며, 이로 인한 교통 혼잡해소에 많은 시간과 비용이 소모된 바 있다. 이에 정부와 경찰청에서는 교통신호시스템의 비상대응력을 고도화하기 위해 무정전전원장치(UPS: Uninterruptible Power Supply)의 도입을 추진 중에 있다. 본 연구에서는 교통신호기의 제어 용량을 고려하여 최소 2시간 지속가능한 전원보상용량을 산정하고, 산정 용량을 기준으로 개발된 규격은 시제품 실험을 통하여 전원보상 요구 성능을 검증하였다. 실험결과 개발된 규격은 충분히 요구 성능을 만족하였으며 중요교차로 등 대형교차로에서 운영 가능한 것으로 나타났다.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1144-1153
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• 2015

The resonant mechanism of reradiation interference (RRI) over 1.7MHz from power transmission lines cannot be obtained from IEEE standards, which are based on researches of field intensity. Hence, the resonance is ignored in National Standards of protecting distance between UHV power lines and radio stations in China, which would result in an excessive redundancy of protecting distance. Therefore, based on the generalized resonance theory, we proposed the idea of applying model-based parameter estimation (MBPE) to estimate the generalized resonance frequency of electrically large scattering objects. We also deduced equation expressions of the generalized resonance frequency and its quality factor Q in a lossy open electromagnetic system, i.e. an antenna-transmission line system in this paper. Taking the frequency band studied by IEEE and the frequency band over 1.7 MHz as object, we established three models of the RRI from transmission lines, namely the simplified line model, the tower line model considering cross arms and the line-surface mixed model. With the models, we calculated the scattering field of sampling points with equal intervals using method of moments, and then inferred expressions of Padé rational function. After calculating the zero-pole points of the Padé rational function, we eventually got the estimation of the RRI’s generalized resonant frequency. Our case studies indicate that the proposed estimation method is effective for predicting the generalized resonant frequency of RRI in medium frequency (MF, 0.3~3 MHz) band over 1.7 MHz, which expands the frequency band studied by IEEE.

• Journal of the Korean Data and Information Science Society
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• 제26권5호
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• pp.1117-1128
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• 2015

오늘날 ICT기술의 눈부신 발전으로 많은 부분에 정보화와 자동화가 이루어져 있으며, 제조업에서도 경쟁우위를 확보하기 위해 설계, 생산 공정의 자동화와 정보시스템을 도입하고 있다. 그러나 정보화 투자 여력이 없는 영세 중소제조 기업의 경우 생산현장에서 정보화의 힘이 미치지 못하고 있으며, 작업자의 경험과 수기데이터에 의존하여 생산 공정을 관리하고 있는 실정이다. 수기데이터로 관리되고 있는 제조공정에서는 불량 발생 시 불량원인을 명확히 밝혀내는데 한계가 있다. 본 연구에서는 수기데이터로 관리되고 있는 중소제조 자동차 부품 가공공정에 대하여, 수기데이터를 수집, 향후 센서데이터를 활용할 수 있도록 중소 제조 맞춤형 분석시스템을 구축하고, 중요도가 큰 일부 공정에 대하여 품질에 영향을 미치는 핵심요인을 4M관점에서 분석하였다. 분석결과, 호기별 불량수량에는 유의한 차이가 없었으며, 원자재, 생산수량, 작업자간 유의한 차이가 있는 것으로 분석되었다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 추계학술대회 논문집(제1권)
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• pp.419-424
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• 2006

최근, 국민소득 증대와 주5일제 근무 확산으로 낚시를 포함한 레저수요가 가일층 증가하고 있고 더불어 낚시어선을 포함하는 소형선박의 척수도 매년 증가하고 있는 추세이지만, 소형 선박의 수리, 유지관리 등을 목적으로 해상에서 육상으로 선박을 끌어올리는 상가작업은 소형조선소의 작업공간, 예인비용, 작업공기, 안전측면에서 많은 단점으로 지적되고 있다. 이에, 본 연구에서는 연안 소형 선박 수리, 유지관리를 위한 Floating dock 시스템 개발의 기초연구로서 Floating dock 시스템 개념정립 및 소형선박의 도크내 유입 ${\cdot}$ 출, 계류기능 등을 모형시험 ${\cdot}$ 검증 등을 통해 개념설계 도서를 작성함으로서 향후, 소형조선소의 작업공간, 인력 및 공기단축 등에 따른 경상비용 절감과 소형선박 유지관리용 Floating dock 개발, 보급을 통한 신규물량 창출로 경영수지 개선에 기여하고자 한다.