• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.464-466
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• 2003

우리나라는 1980년대 이후 급격한 경제성장에 따라 년 10%대의 급격한 전력수요 증가를 보이고 있으며, 1인당 전력소비량 또한 매년 큰 폭의 증가세를 보이고 있다. 특히, 주요한 전력 수요 증가지대가 경인 지역에 집중되어 있으나, 이 지역은 인구 밀집지역으로 환경과 입지적인 관점에서 새로운 발전원을 개발하기가 곤란하다. 이에 따라 대용량 발전단이 있는 중서부권이나 영동권으로부터 수요지인 경인지역으로의 대규모 전력전송로가 필요하게 되었다. 이에 따라 1979년부터 765kV로의 전압격상을 준비하였으며, 1983년부터 765kV 연구개발을 시작하여 1997년 10월에 1차로 765kV 송전선로에 345kV 가압을 시작하여 2002년 5월 8일에 역사적인 765kV 송전을 개시하였다. 전력계통운용에서 765kV 송전선로의 중요도가 매우 커지게 됨으로써 국내 최초로 적용되는 765kV송전선로 보호시스템의 정동작 유무를 정확히 판단하여 전력계통의 보호 신뢰도를 향상시키는 문제가 중요하게 대두 되었다. 본 논문에서는 시각동기장치가 부착된 보호계전기 시험장치를 이용하여 양단 변전소에서 동시에 EMTP와 RTDS 둥으로 검토된 송전선로 고장상태를 인가하여 보호시스템의 정동작 여부를 종합적으로 판정하는 시험 기술을 개발하여 실적용한 사례와 향후 사용 계획에 대해서 기술하였다.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.560-565
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• 2006

Sprinkler system is the most effective fire suppression with high confidence among active fire extinguishing systems. According to the installation of the related system on buildings, more separation area of fire protection can be considered to the fire protection design, and also lower differential pressure (12.5 Pascal) is permitted on lobby of fire escape stairs and emergency elevator (25 Pascal shall be considered for none sprinkler system) with economic factor. More details will be handled on the related studies.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.4
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• pp.273-279
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• 2010

Purpose: The purpose of this in vitro study was to compare the marginal adaptation of a ceramic-pressed-to-metal restoration with traditional metal-ceramic restoration. Materials and methods: Duplicating the prepared resin tooth, 20 metal dies were fabricated. Twenty metal copings of 2 groups which were metal ceramic restoration and pressed to metal restoration were fabricated. The marginal opening of each coping was measured with Microscope (BX 60M-36E $41D^{(R)}$: Olympus, Japan). After porcelain build-up, the marginal opening of metal ceramic restoration and pressed to metal restoration ($PoM^{(R)}$: Ivoclar vivadent., Liechtenstein) were also evaluated in the same method. The measurements were analyzed using Wilcoxon Signed Ranks test and Mann-Whitney U test. Results: Within the limits of this study, the results were as follows. 1. Metal-ceramic restorations in coping state ($64.93{\pm}12.48\;{\mu}m$) in compared with Metal ceramic restorations after porcelain build-up ($63.43{\pm}12.86\;{\mu}m$) had no significant difference in marginal adaptation. 2. Pressed-metal-ceramic restorations in coping state ($50.00{\pm}12.28\;{\mu}m$) in compared with Pressed metal ceramic restorations after porcelain build-up ($56.72{\pm}13.80\;{\mu}m$) had no significant difference in marginal adaptation. 3. Metal-ceramic restorations in compared Pressed-metal-ceramic restorations had no significant difference in marginal adaptation. Conclusion: Pressed-metal-ceramic restorations have the advantage of being technically less change through using of the lost-wax technique and this allows for the convenience of a full-contour ceramic wax-up as opposed to the more technique-sensitive layering method. Pressed-metal-ceramic restorations may be considered in clinic on the basis of the result of this study and the advantage of this system.

• Journal of Korea Water Resources Association
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• v.52 no.5
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• pp.373-380
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• 2019

In this study, the optimum pump operation technique is suggested to decrease the damage rate of water distribution system. Pump operation system was developed to achieve the effective pump operation. Pressure sensors which can communicate with pumps are installed at the end of water distribution system. Pump operation system can control the pressure of water pump according to data sent from the pressure sensors. Therefore, water distribution system can reduce the pressure and maintain enough pressure which can supply the demand of water users. For proving effectiveness of new system, reliability model was introduced to compare the results of damage rates between the maintaining high pressure and selective pressure in water pump. Unsteady analysis was conducted with several scenarios. And the results were used to calculate the probability of pipe breakage. From the results, it was found that new pump operation system can reduce the energy usage and probability of pipe breakage by applying to pumps.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.8 no.4
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• pp.63-69
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• 1994

본 논문에서는 원자력 발전소 정상 운전시 제어 및 상태벡터 가변을 고려한 최적제어 문제가 연구되었다. 제어기 설계시 제어 및 상태벡터가 변하는 경우를 고려하여 제어기를 구성하고 운전중 상태 및 제어벡터 가변에 따라 변하는 제어기의 최적이득을 정한정 및 양한정 행렬을 이용해 구함으로서 운전중의 부하변화 및 외란에 대해 실질적인 최적제어가 되도록 하였다. 시뮬레이션 결과 정상상태의 부하변화에 대해서는 제어목적에 맞게 잘 추종하고 있었고 원자로 입·출구 및 가압기 계통의 외란에 대해서는 정상상태시의 부하변화와 같은 응답특성을 갖으나 적은 외란에 대해서도 부하가 크게 변하는 회과를 갖는 응답특성을 보이고 있어 외란이 시스템 전반에 미치는 영향이 매우 큼을 보이고 있다.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.382-384
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• 1996

This paper introduces the controller development of booster multi-pump system with constantly estimated control algorithm. Through analyzing by the experiment of optimal pressure with a certain flow rate. The larger pressure processing apparatus in microprocessor makes optimal water-supplying. This method is implemented with the only pure control algorithm without any other mechanical or circuitry apparatus. Also, Pump's life is lengthened by exchanging simple on, off and rotational inverter control. Optimal condition for pump is adjusted by the inverter control, and compact control panel helps the booster system install in real field.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.9
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• pp.643-657
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• 2009

This paper introduces the current nuclear experimental research activities in KAERI, the unique nuclear research institute in Korea, and the universities in Korea to solve and assess the issues which have been faced in the design of new reactors such as APR1400, SMART, GEN-IV reactors as well as fusion reactor. Also the experimental evaluations of safety for operating nuclear plants have been presented. The nuclear thermalhydraulic experiments performed in such organizations are classified the fundamental test, the separated effect test, and the integral effect test with ATLAS and SNUF. Introduction is deployed according to institutes. Finally, the future works and the direction of research voyage in the nuclear thermal-hydraulic field were suggested.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.852-855
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• 2009

고압 미분탄 공급 기술은 건식 석탄가스화기 시스템의 안정적인 연속운전을 위한 핵심이 되는 기술로서, 본 연구에서는 스크류피더 방식 및 기류수송 방식의 pilot급 고압 미분탄 공급장치를 이용한 미분탄 공급량 제어 기술 개발을 진행하였다. 그리고, 일반적으로 dense phase 형태로 다량의 미분탄을 공급하는 기류수송 방식 고압 미분탄 공급장치에서 가스화기로 공급되는 미분탄의 공급량을 감소시키기 위하여 다공 chamber를 통하여 가압 질소를 공급할 경우, 차압이 증가함에 따라 미분탄의 공급량이 증가하기는 하지만 lean 또는 medium phase 형태로 미분탄 공급량 제어가 가능함을 확인할 수 있었다.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1997-1998
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• 2006

In this paper, we propose a remote control system which is used by internet network system in the small water booster supply. So far, TMTC(Tele Metering Tele Control) has been used to control and monitor small water booster pump. But it is possible and easy to control and observe local booster panel with the rapid development of internet, This new system is to provide operators and managers with sufficient information and control in order to implement the operation in an efficient and economical way. This system consists of three parts that are controller, netpump server and netview client. Controller has a dual architecture. The motive for installing controller is the continuous production and supply of drinking water.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.299-302
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• 2009

The objective of the present study is to analyze the transient flow through theejector system with the help of a computational fluid dynamics (CFD) method. An attempt is made to investigate the interesting and conflicting phenomenon of the infinite entrainment into the primary stream without an infinite mass supply from the secondary chamber. The results obtained show that the one and only condition in which an infinite mass entrainment can be possible in such types of ejectors is the generation of a re-circulation zone near the primary nozzle exit. The flow in the secondary chamber attains a state of dynamic equilibrium of pressures at the onset of the recirculation zone. A steady flow in the ejector system is valid only after this point.