• 한국수소및신에너지학회논문집
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• 제17권2호
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• pp.133-140
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• 2006

The performance of proton exchange membrane fuel cell was decreased by reverse voltage using fuel starvation. Performance decrease in local area could be affected by duration and extent of reverse voltage. Hydrogen and air stoichiometic ratio was used to find the experimental condition of abrupt voltage decrease. LabVIEW was used to make control logic of automatic load off system in preset voltage. Reverse voltage experiment was done down to -1.2 V at constant current condition. When fuel cell voltage was reached to preset voltage, electronic load was disconnected to make open circuit voltage for 1 minute. Fuel cell performance was checked every 5 cycle and the degree of performance decrease and/or recovery was estimated. Ohmic resistance and charge transfer resistance were increased and platinum surface area was reduced 41% after reverse voltage experiment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.488-490
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• 2004

The technical data for transmission line design and maintenance are calculated by a very complicated numerical formula so it is almost impossible to solve them by hand. Therefore the TOWER+ EXPERT SYSTEM was developed to systematically support technical data for transmission line design and maintenance. This system is able to calculate technical data which is applied to all conductors in our county, - that is 12 kinds of systems with 86 numbers of standard conductors, - and is programed to be user friendly by adopting dialogue windows, menu selection functions. Moreover, it minimizes input data by automatically providing standard transmission line design data, and it includes guidance of applicable work, program usage, data input process, help, explanation of terms and automatic error recovery functions that even a beginner can easily use.

• Nuclear Engineering and Technology
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• 제49권3호
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• pp.632-637
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• 2017

Even though the potential for an accident in nuclear power plants is very low, multiple emergency plans are necessary because the impact of such an accident to the public is enormous. One of these emergency plans involves a robotic system for investigating accidents under conditions of high radiation and contaminated air. To develop a robot suitable for operation in a nuclear power plant, we focused on eliminating the three major obstacles that challenge robots in such conditions: the disconnection of radio communication, falling on uneven floors, and loss of localization. To solve the radio problem, a Wi-Fi extender was used in radio shadow areas. To reinforce the walking, we developed two- and four-leg convertible walking, a floor adaptive foot, a roly-poly defensive falling design, and automatic standing recovery after falling methods were developed. To allow the robot to determine its location in the containment building, a bar code landmark reading method was chosen. When a severe accident occurs, this robot will be useful for accident condition monitoring. We also anticipate the robot can serve as a workman aid in a high radiation area during normal operations.

• Nuclear Engineering and Technology
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• 제49권5호
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• pp.896-904
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• 2017

Several Generation IV nuclear reactor concepts have goals for optimizing investment recovery through phased introduction of multiple units on a common site with shared facilities and/or reconfigurable energy conversion systems. Additionally, small modular reactors are suitable for remote deployment to support highly localized microgrids in isolated, underdeveloped regions. The long-term economic viability of these advanced reactor plants depends on significant reductions in plant operations and maintenance costs. To accomplish these goals, intelligent control and diagnostic capabilities are needed to provide nearly autonomous operations with anticipatory maintenance. A nearly autonomous control system should enable automatic operation of a nuclear power plant while adapting to equipment faults and other upsets. It needs to have many intelligent capabilities, such as diagnosis, simulation, analysis, planning, reconfigurability, self-validation, and decision. These capabilities have been the subject of research for many years, but an autonomous control system for nuclear power generation remains as-yet an unrealized goal. This article describes a functional framework for intelligent, autonomous control that can facilitate the integration of control, diagnostic, and decision-making capabilities to satisfy the operational and performance goals of power plants based on multimodular advanced reactors.

• 한국응급구조학회지
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• 제25권1호
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• pp.205-221
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• 2021

Purpose: This paper is to determine whether automatic defibrillators (AEDs) deployed across communities make a contribution to prevent death in patients with acute cardiac arrest out-of-hospital. Methods: A total of 30,179 cases of cardiac arrest investigation data from the Korea Centers for Disease Control and Prevention was matched to those on emergency medical statistics drawn from annual report for the 2018 Central Emergency Medical Center, and statistics from the National Statistical Office in 2018. Results: Multiple logistic regression analyses revealed that availability of emergency medical resources across associated with different survival rates at emergency room after taking variability of the patient's personal characteristics and episodic situational characteristics held constant. The survival rate was 1.71 times higher for patients living in communities with more than 105 AEDs avaiable per 100,000 inhabitants than for those living in communities with less than 55 AEDs. Conclusion: The survival-related factors of patients with acute cardiac arrest that occurred out-of-hospital were found to be associated with patients' and episodic situational characteristics. The hospital stage were found to be associated with patients characteristics and episodic situational characteristics, The variability of AED available in a community has an impact on survival rate after emergency room treatment.

• 한국기계가공학회지
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• 제19권10호
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• pp.1-7
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• 2020

In this study, a multichannel gas-liquid microextraction system is designed by integrating the automatic elution of extraction line and multichannel gas-purging liquid phase microextraction. The system uses an injection pump and inert gas to push the extraction solvent to a sample bottle of a gas-phase color autosampler and then implements multichannel gas-liquid microextraction and gas chromatography-mass spectrometry. The system also employs a three-way integrated micro-high-temperature heater, syringe pump, and microflow controller to realize the simultaneous processing of multiple groups of samples, thus improving the sample pretreatment speed and reproducibility and reducing human error. Autoinjection experiments were implemented with polycyclic aromatic hydrocarbon standard samples. The experiments show that the average recovery rate of the system exceeds 70%, and the relative standard among the channels is less than 15%.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 춘계학술대회
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• pp.310-313
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• 2022

정수된 물을 각 가정으로 공급하기 위한 관로에는 중요 지점에 유량계, 압력계 등의 계측기를 설치하여 실시간으로 감시하고 있다. 계측된 데이터는 무선 또는 유선 통신을 통해 중앙조정실까지 취득이 되나, 간헐적으로 통신 장애가 발생하여 데이터를 취득하지 못하는 경우가 발생한다. 이후 통신망이 복구되더라도 장애 기간의 데이터가 현장에 저장되지 않거나, 혹은 저장이 되었더라도 자동으로 데이터베이스에 데이터를 저장하지 못하고 있는 실정이다. 저비용으로 이를 해결하기 위해 현장에 보편적으로 설치된 PLC와 호환되는 모듈을 개발하여 데이터 로깅, 자동으로 데이터베이스에 데이터를 복구할 수 있도록 하고자 한다.

• 한국전기전자재료학회논문지
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• 제35권2호
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• pp.143-148
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• 2022

For the purpose of treating health checkups and recovery of patients in a super-aged society, hospitals use devices designed with a reduction circuit of electromagnetic waves associated with the specific absorption rate of electromagnetic waves absorbed by the human body. In this paper, we proposed a filter improvement design method capable of reducing electromagnetic waves. As a result of confirming the validity of the proposed technique through simulation and experimental results, the following result values were obtained. Applying the common-mode (CM) inductor 4 mH to a calibration circuit, noise decreased in a multiband spectrum. Using the differential mode(DM) inductor 40 µH element in the primary calibration circuit, the noise decreased by 15 dB or more in the 3 MHz band spectrum. Also, applying the Admittance Capacitance (Y-Cap) 10 nF element in the secondary calibration circuit resulted in the decrease by more than 30 dB in the band spectrum before 2 MHz. After using a common-mode inductor 4 mH element in the tertiary calibration circuit, it decreased by more than 15 dB in the band spectrum after 2 MHz.

• 핵의학기술
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• 제16권2호
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• pp.3-6
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• 2012

방사성의약품 제조 후 품질관리의 중요성이 점점 커지고 있다. 품질관리 항목에는 물리적 성상, PH, 핵종의 순도 측정, 화학적 순도 측정, 방사화학적 순도 측정, 내독소 검사, 크립토픽스 잔류량 측정 등이 있다. 내독소 검사는 발열 및 쇼크등을 일으킬 수 있는 그람음성간균의 리포다당질이 포함된 검체가 인체에 주입되는 것을 방지하기 위한 검사법이다. FASTlab module을 이용하여 합성된 $^{18}F$-FDG의 내독소 검사 시행 시 간섭요인이 발생하여 제대로 된 검사가 시행되지 못하여 희석하는 방법을 이용하였다. LAL free water를 이용하여 비색법은 25 ${\mu}l$, 겔화법은 200 ${\mu}l$를 최소단위로 하여 희석배수가 10배수를 초과하지 않는 범위내에서 희석배수를 10배수, 20배수, 30배수, 40배수로 하여 희석하였다. 희석된 시약을 겔화법은 STT와 PCT에 각각 200 ${\mu}l$를 주입하고 Incubator에 $37^{\circ}C$로 1시간동안 배양하여 겔형성 정도를 확인하고, 비색법은 25 ${\mu}l$를 최소단위로 하여 위와 같이 희석한다. 희석된 시약은 ENDOSAFE-PTS의 Dilution factor를 입력하고 배수 당 하나의 카트리지를 4곳의 주입구에 25 ${\mu}l$씩 주입하고 결과 데이터를 확인한다. 결과는 겔화법은 FASTlab의 경우 40배수에서만 겔이 형성되었고, TRACERlab Mx의 경우 거의 모든 배수에서 겔이 형성되었지만 간헐적으로 형성되지 않는 경우도 있었다. 비색법은 FASTlab의 경우 40배수에서만 Spike Rxn time CV, Sample Rxn time CV, Spike recovery 모두 정상범위 안에 포함되었다. TRACERlab Mx의 경우 10배수에서 Spike Rxn time CV, Sample Rxn time CV, Spike recovery 모두 정상범위 안에 포함되었다. FASTlab에서 생산된 방사성의약품은 중화제인 $H_3PO_4$가 PCT내에 겔 형성에 관여하는 $Mg^{2+}$이온과 결합하여 겔 형성을 하지 못하는 것으로 추측된다. 이에 희석을 할 경우 $H_3PO_4$ 양이 줄어 간섭효과를 제거할 수 있었다. 엔도톡신 검사에서 간섭인자들은 무수히 존재한다. 이 간섭인자들은 합성장치나 시약에 따라 달라질 수 있으므로 이와 같은 간섭인자들을 극복하기 위한 노력으로 품질검사의 정확성과 신뢰를 제공하도록 해야 할 것이다.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제10권7호
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• pp.199-204
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• 2021

디지털변전소는 전력망 지능화를 위해 감시, 계측, 제어·보호, 운전 등 변전소를 구성하는 전력설비 기능과 통신방식을 국제표준인 IEC61850 기반으로 디지털화한 변전소를 말한다. 지능화된 운영시스템을 기반으로 효율적인 전력설비의 감시제어가 가능하며, 사고 발생 시 자동 복구 기능과 원격제어가 가능해 신속한 전력 장애 복구가 가능하다. 디지털 기술의 발달과 친환경 신재생에너지 및 전기차의 도입이 확대 되면서 직류 배전시스템의 보급이 확대될 전망이다. MVDC는 기존 송전계통에 적용되는 HVDC와 수용가에서의 LVDC 사이의 전압 레벨 및 전송용량을 갖는 직류 선로를 활용한 시스템이다. 대부분의 전력설비들이 교류 중심인 기존변전소의 기존 선로를 직류 선로로 변환하면 송전 손실 감소 및 더 큰 전류 용량이 확보된다. 디지털변전소의 프로세스 버스는 베이 레벨과 프로세스 레벨의 설치된 장치 간을 연결하는 이더넷스위치 등의 통신장비로 구성된 통신네트워크이다. 기존 디지털변전소에 MVDC 연계를 위해 프로세스 레벨을 교류부와 직류부로 나누어 두 개의 버스로 구성을 하였고 감시, 제어만 아니라 진단 IED와 연계되어 종합적으로 관리할 수 있는 시스템을 제안하였다.