• 전기학회논문지
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• 제64권7호
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• pp.1130-1136
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• 2015

Most equipments which are used to measure the switching power of the turnout depend on imports. As the data is limited to the measurements of the switching power, it is said that the equipment is insufficient to check the errors of the turnout and the electrical point machine, and set up the data for operating and maintenance. We studied not only measurements of the switching power of all turnout being used in domestic but also the development of the turnout performance total analysis equipment which can measure switching time, voltage, and current etc. at the same time. Considering that switching power of the turnout is the most basic element to check the irregularities of the turnout, in this paper, we analyzed the irregularities of the turnout through correlation between switching power of the turnout, voltage, and current of the electrical point machine. Also we performed test in commercial railway line where the turnout of MJ81 type and NS type was installed. And it is said that the test results can be used as basic technologies for ICT based real-time diagnosis and monitoring of the turnout.

• 스마트미디어저널
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• 제5권3호
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• pp.81-87
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• 2016

세계의 글로벌화에 따라 움직이는 물동량이 크게 증가하면서 선박의 해상 운송 능력 향상을 위해 선박의 대형화가 지속적으로 이루어지고 있으며 선박의 수도 크게 증가하고 있는 추세에 따라 선박에서의 위험지역 모니터링에 대한 관심 이 증대되고 있고 국제해사기구(IMO)를 중심으로 선박안전관련 국제협약의 기준이 강화되고 있는 실정이다. 국내는 2012년 해양경찰청에 의해 선박 위치정보 기반의 선박 사고예측 및 예방 시스템이 구축되었으나, 최근 세월호 사건 등 선박 사고에 대한 대응의 문제점이 지적되고 있는 실정으로 위의 문제점을 해결하고자 본 논문을 통해 위험 구역 경보 및 위급상황 시 선박 운항 위치정보를 자동으로 전달해주는 DGPS를 탑재한 웨어러블 타입의 즉각 응급대응 시스템을 설계를 하고자 한다.

• 한국항공운항학회지
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• 제21권1호
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• pp.80-86
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• 2013

In an effort to decrease aviation accident worldwide, development of aviation safety management has been sought through aviation index and standardization, both by establishing SMS(Safety Management System). It also needs to be done in the domestic. both study on SMS which ICAO recommends and setting the top priority safety goal, each differently classified by nations. Accordingly, defining safety index and developing continuous monitoring approach. Aircraft accident reporting system in Air Force does not operate in a open approach method due to its uniqueness related to mission achievement. Therefore, limits of utilizing the recent worldwide aircraft data sharing and analyzing results to prevent accident is inevitable. This paper introduces an overview of ECCAIRS 5 which become the standard for the recent worldwide aviation safety reporting and data exchange system. Also using ECCAIRS 5, aircraft accident cases of the Air Force are classified such as accident type, year, month, occurrence category, and flight phase. The result of the study will provide a guide line for utilizing the civil system in prevention of future military aviation accidents.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 춘계학술발표회논문집(1)
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• pp.264-270
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• 1998

This research broadens the prime concern of nuclear power plant operations from safe performance to both economic and safe performance. First emergency diesel generator is identified as one of main contributors for the lost plant availability through the review of plants forced outage records. The framework of an integrated architecture for performing modern on-line condition for operational availability improvement is configured in this work. For the development of the comprehensive sensor networks for complex target systems, an integrated methodology incorporating a structural hierarchy, a functional hierarchy, and a fault-system matrix is formulated. The second part of our research is development of intelligent diagnosis and maintenance advisory system, which employs Bayesian Belief networks (BBNs) as a high level reasoning tool incorporating inherent uncertainty use in probabilistic inference. Our prototype diagnosis algorithms are represented explicitly through topological symbols and links between them in a causal direction. As new evidence from sensor network development is entered into the model especially, our advisory of system provides operational advice concerning both availability and safety, so that the operator is able to determine the likely modes, diagnose the system state, locate root causes, and take the most advantageous action. Thereby, this advice improves operational availability

• 한국전자통신학회논문지
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• 제5권3호
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• pp.332-338
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• 2010

본 논문에서는 유비쿼터스 헬스케어를 위한 Zigbee/PLC 게이트웨이 시스템을 구현하였다. 게이트웨이를 이용하여 Zigbee 통신과 전력선 통신 간의 원활한 정보 교환을 위한 프로토콜 변환 알고리즘을 설계 및 구현하였다. Zigbee/PLC 게이트웨이 시스템은 센서 모듈, Zigbee 모듈, 전력선 모뎀, 게이트웨이로 구성되며, 움직이는 물체가 무선 센서에 감지되면 Zigbee 모듈을 통해 게이트웨이로 전송된다. Zigbee/PLC 게이트웨이에서는 전송받는 데이터를 분석하여, 실시간 모니터링을 위해 전력선 통신망을 통해 외부로 전송된다. 구현된 시스템은 독거노인 활동량 분석, 방범 시스템, 홈 네트워크 서비스 등 다양한 분야에서 활용가능하다.

• 한국컴퓨터정보학회논문지
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• 제14권12호
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• pp.25-32
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• 2009

본 논문은 홈 네트워크 구축에 있어서 저속의 PLC(Power Line Communication) 통신기술을 활용하여 지능형 홈 네트워크 시스템을 구축하였으며, UPnP 브릿지를 통하여 TCP/IP 기반의 원격 제어 및 모니터링 시스템을 설계하였다. 또한, 지능형 홈 네트워크 내부의 제어 모듈에 대한 통신은 저속 저력선 기반의 SCP( Simple Control Protocol)을 설계하여 각 장치들 사이를 연결하여 제어 할 수 있도록 구현 하였다. PLC 기반의 지능형 홈 네트워크 내부에 새로운 UPnP 장치가 연결 되었을 때는 등록된 UPnP 장치의 정보에 따라 UPnP 브릿지를 통하여 장치를 모니터링 하도록 기능을 구현하였다. 전력선 통신 기반의 장치 제어 및 각 장치에 대한 UPnP 장치로의 구현은 TCP/IP 기반의 원격 제어 및 장치 관리가 효율적이며, 홈 네트워크상의 다양한 장치에 대한 장치 정보를 쉽게 모니터링 하고 관리할 수 있는 기능을 제공한다.

• 대한기계학회논문집
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• 제9권6호
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• pp.757-766
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• 1985

본 연구에서는 기계공업 분야에서 많이 이용되는 구조용 합금강인 Cr-Mo강 (SCM4)과 쾌삭강(SUM31, SUM24L)과의 이종강봉 마찰용접에서 소성변형중에 발생된 초 기 AE량과 용접 품질(강도)제어 사이에 역시 정량적 상관성이 성립함을 용접 회전수, 용접에너지, 용접 업셋 및 용접 시간 등을 매개 변수로 하여 실험과 계산을 통해 입증 하고, 이를 상관식의 95% 신뢰성을 확인한 후, 본 연구의 최종 목적으로서, 마찰용접 평가의 자동화가 이루어지게 하였다.

• Nuclear Engineering and Technology
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• 제56권10호
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• pp.4327-4334
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• 2024

Preventive Maintenance(PM) for safety component during power operation at nuclear power plants, On-Line Maintenance(OLM) refers to intentionally entering the Limited Condition of Operation(LCO) specified in the Technical Specification(TS) for safety-related systems and components in order to perform preventive maintenance within the Allowed Outage Time (AOT). This study assessed the feasibility of conducting OLM at the domestic APR1400 nuclear power plant. It focused on preventive maintenance duration and risk perspectives. A total of 78 FEGs were developed for 4450 facilities, considering system functions and preventive maintenance scope during output operation for eight safety-related systems. Additionally, maintenance items included in FEGs were selected, designated as targets for OLM, and their maintenance durations were evaluated and compared with AOT for each maintenance item. As a result, the Auxiliary Feedwater and Essential Chilled Water systems were identified as systems allowing OLM. Furthermore, utilizing the Risk Monitoring System (RIMS), the increased risk value due to the unavailability of target equipment during preventive maintenance was analyzed to determine whether it falls within the acceptable range. Regarding the temporary risk increase caused by OLM, it was observed that in all systems, it falls within Zone III according to NUMARC93-01 standards, allowing for normal equipment arrangement for OLM. However, according to the risk increase standards rate in domestic nuclear power plants, when maintaining the A-train in four systems including Component Cooling Water, they are all evaluated as 'Orange,' indicating that measures for risk mitigation are necessary for OLM to be feasible. When considering extending AOT up to 1.6 times the maintenance time, the risk increase falls within Zone III according to permissible change in risk standards, indicating that AOT extension might be feasible based solely on risk changes. To apply OLM within the permissible risk management scope in domestic nuclear power plants, regulatory policies need to allow voluntary LCO entry for preventive maintenance, necessitating clear determination by regulatory agencies using risk-informed policies. While OLM seems viable concerning maintenance duration and quantitative risk aspects, for inducing regulatory policy changes, comprehensive OLM guidelines are necessary, including risk management strategies.

• Nuclear Engineering and Technology
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• 제27권4호
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• pp.562-570
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• 1995

근래의 ABB/CE형 가압경수로들은, 정상운전 및 예상운전과도상태 중에 허용핵연료설계제한치가 위배되는 것을 방지하기 위하여, 노심 운전상태를 감시하는 디지탈노심감시계통, COLSS(Core Oper-ating Limit Supervisory System)를 보유하고있다. COLSS의 주요 기능 중 하나는. 측정되는 운전조건에 대한 최소 핵비등이탈률을 계산하여, 핵비등이탈에 대한 과출력여유도를 감시하는 것이다. COL-SS에서 최소 핵비등이탈률을 계산하는데 사용되는 CETOP-D 모델은 상세부수로분석코드인 TORC 모델에 대해 보수적으로 벤치마킹되며, 보정상수로서 고온집 합체의 입구유량인자를 사용하고 있다. 본 연구에서는 CETOP-D 입구유량인자를 가장 제한적인 운전조건에서 보수적인 단일 값으로 결정하는 ABB/CE 방법을 배제하고, 운전조건에 따른 CETOP-D 입구유량인자 변화를 상관식형태로 결정하는 “CETOP-D 입구유량인자 최적화기법”을 개발하였다. 개발된 방법을 영광 3,4호기 초기노심의 노심운전영역에 적용한 결과, 기존의 ABB/CE 방법에 비하여 정상운전영역에서 핵비등이탈에 대한 과출력여유도가 2% 가량 증가하였다.

• 한국대기환경학회지
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• 제32권2호
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• pp.216-232
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• 2016

In present, the Seoul City is undergoing traffic congestion problems caused by rapid urbanization and population growth. Thus the City government has reorganized the mass transportation system since 2004 and the subway has become a very important means for public transit. Since the subway system is typically a closed environment, the indoor air quality issues have often raised by the public. Especially since a huge amount of PM (particulate matter) is emitted from ground tunnels passing through the subway train, it is now necessary to assess the characteristics and behaviors of fine PM inside the tunnel. In this study, the concentration patterns of $PM_1$, $PM_{2.5}$, and $PM_{10}$ in the Seoul subway line-2 were analyzed by real-time measurement during winter (Jan 13, 2015) and summer (Aug 7, 2015). The line-2 consisting of 51 stations is the most busy circular line in Seoul having the railway of 60.2 km length. The the one-day average $PM_{10}$ concentrations were $148{\mu}g/m^3$ in winter and $66.3{\mu}g/m^3$ in summer and $PM_{2.5}$ concentrations were $118{\mu}g/m^3$ and $58.5{\mu}g/m^3$, respectively. The $PM_{2.5}/PM_{10}$ ratio in the underground tunnel was lower than the outdoor ratio and also the ratio in summer is higher than in winter. Further the study examined structural types of underground subsections to explain the patterns of elevated PM concentrations in the line-2. The subsections showing high PM concentration have longer track, shorter curvature radius, and farther from the outdoor stations. We also estimated the outdoor PM concentrations near each station by a spatial statistical analysis using the $PM_{10}$ data obtained from the 40 Seoul Monitoring Sites, and further we calculated $PM_{2.5}/PM_{10}$ and $PM_1/PM_{10}$ mass ratios near the outdoor subway stations by using our observed outdoor $PM_1$, $PM_{2.5}$, and $PM_{10}$ data. Finally, we could develop pollution maps for outdoor $PM_1$ and $PM_{2.5}$ near the line-2 by using the kriging method in spatial analysis. This methodology may help to utilize existing $PM_{10}$ database when managing and control fine particle problems in Korea.