• International Journal of Fuzzy Logic and Intelligent Systems
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• 제4권2호
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• pp.187-192
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• 2004

In this paper, we proposed the method to design fuzzy controller using the experience of the operating expert and experimental numeric data for the robust control about the noise and disturbance instead of the traditional PID controller for the main steam temperature control of the thermal power plant. The temperature of main steam temperature process has to be controlled uniformly for the stable electric power output. The process has the problem of the hunting for the cases of various disturbances. In that case, the manual action of the operator happened to be introduced in some cases. We adopted the TSK (Takagi-Sugeno-Kang) model as the fuzzy controller and designed the fuzzy rules using the informations extracted directly from the real plant and various operating condition to solve the above problems and to apply practically. We implemented the real fuzzy controller as the Function Block module in the DCS(Distributed Control System) and evaluated the feasibility through the experimental results of the simulation.

• 한국초전도ㆍ저온공학회논문지
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• 제23권4호
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• pp.44-48
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• 2021

In order to obtain ultra-high resolution MRI images, research and development of 11 T or higher superconducting magnets have been actively conducted in the world, recently. The high-temperature superconductor (HTS), first discovered in 1986, was very limited in industrial application until mid-2010, despite its high critical current characteristics in the high magnetic field compared to the low-temperature superconductor. This is because HTS magnets were unable to operate stably due to the thermal damage when a quench occurred. With the introduction of no-insulation (NI) HTS magnet winding technology that does not burn electrically, it could be expected that the HTS magnets are dramatically reduced in weight, volume, and cost. In this paper, a 6 T-class NI HTS magnet for basic characteristic analysis was designed, and a distributed equivalent circuit model of the NI coils was configured to analyze the charging current characteristics caused by excitation current, and the charge delay phenomenon and loss were predicted through the development of a simulation model. Additionally, the critical current of the NI HTS magnets was estimated, considering the magnetic field, its angle and temperature with a given current. The loss due to charging delay characteristics was analyzed and the result was shown. It is meaningful to obtain detailed operation technology to secure a stable operation protocol for a 6T NI HTS magnet which is actually manufactured.

• 한국안전학회지
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• 제13권1호
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• pp.26-33
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• 1998

This paper subdivided the interior solid into triangular shape of equal size to calculate the temperature distribution around the square heat source of it, and compared calculated values with measured ones. The result obtained are as follows. 1) It was found that we can calculate the temperature distribution around the square heat source of interior solid by the variational method of the finite element method as the calculated values were almost accord with the measured ones. 2) The temperature distributed were higher when the distances between heat source were farther and lower when those nearer. 3) Vertical surface temperature distribution is remarkably efficient by thermal conductivities.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.1100-1109
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• 2006

In this study, two different technologies which can measure temperature simultaneously at many points are introduced. One is to use a thermal sensor cable that is comprised of addressable thermal sensors connected in parallel within a single cable. The other is to use an optic fiber with Distributed Temperature Sensing (DTS) system. The difference between two technologies can be summarized as follows. A thermal sensor cable has a concept of 'point sensing' that can measure temperature at accurate position of a thermal sensor. So the accuracy and resolution of temperature measurement are up to the ability of the thermal sensor. Whereas optic fiber sensor has a concept of 'distributed sensing' because temperature is measured by ratio of Stokes and anti-Stokes component intensities of Raman backscatter that is generated when laser pulse travels along an optic fiber. It's resolution is determined by measuring distance, measuring time and spatial resolution. The purpose of this study is that application targets of two temperature measurement techniques are checked in technical and economical phases by examining the strength and weakness of them. Considering the functions and characteristics of two techniques, the thermal sensor cable will be suitable to apply to the assessment of groundwater flow, geothermal distribution and grouting efficiency within 300m distance. It is expected that the optic fiber sensor can be widely utilized at various fields (for example: pipe line inspection, tunnel fire detection, power line monitoring etc.) which need an information of temperature distribution over relatively long distance.

• Ecology and Resilient Infrastructure
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• 제6권2호
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• pp.120-127
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• 2019

본 연구에서는 광섬유 온도 분포 센싱을 통한 제체의 침투 및 붕괴와 같은 물리적 변화 현상을 모니터링하기 위해 중규모 제방 수리실험을 수행하였다. 본 실험의 중규모 실험 제방은 바이오폴리머 흙을 제방 전면에 도포하여 강도를 증진시킨 것으로 월류에 의한 침투 및 붕괴 현상이 일반 제방과는 다르게 나타날 수 있으며, 이러한 현상은 광섬유 온도 분포 센싱을 통해 획득한 온도 변화 정보를 통해 분석할 수 있었다. 제체의 위치별 시간에 따른 온도 변화 자료를 통해 제체 내부의 물리적 변화 및 침투가 발생하는 위치와 시간을 판단할 수 있었다. 본 실험에서는 급격한 온도 변화 시점이 제외지 사면보다 제내지 사면에서 먼저 발생하였으며, 이는 실험에서 제내지 사면이 붕괴된 후에 제외지 사면이 붕괴된 순서와 일치하였다.

• 조명전기설비학회논문지
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• 제21권7호
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• pp.54-60
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• 2007

15개의 광섬유 격자를 이용하여 전력설비의 온도변화를 상시 감시하는 분배형 광섬유 온도센서 시스템을 제작하였다. MEMS 파장가변 필터를 사용하는 복조시스템의 비선형 동작특성에 의한 측정오차를 보상하기 위하여 Fabry-Perot ITU 필터의 투과파장을 기준으로 하는 다항식 피팅 알고리즘을 사용하였다. 실험을 통하여 보상알고리즘이 구동주파수와 무관하게 센서시스템의 정밀도를 유지하는 것을 확인하였으며 기준 온도계로 사용한 써모커플과의 선형화 오차는 약 0.18[%]로 측정되었다.

• 한국환경복원기술학회지
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• 제15권2호
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• pp.127-136
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• 2012

Global climate change and urban heat island have been the main factors which changed leaf burst timing and leaf growth performance in urban forests. Therefore, the ecosystem in urban forests were modified and the types and composition of wildlives, living in the urban forests, were desperately changed due to the urban heat island. This study was done to identify phenological phenomena appeared in urban forests due to the urban climate change by comparing the morphological changes of leaves due to the change of temperature in Spring. The study focused on nine urban forests distributed in Daegu city, where weekly temperature and the morphological changes of the plants were mainly observed. Urban forests had different temperature depending on where each was located in the urban area. The difference of temperature in forests in and outside the urban area was verified by SPSS (Statistical Package for the Social Sciences), which divided the urban forests into about three groups; the one located outside the city, another group located in the middle of the city, and the other located close to the outside forests. The forests located in the middle of the city were showing the earlier leaf burst timing and leaf growth performance, while forests, distributed outside the city, were showing relatively late leaf burst timing and leaf performance.

• Nuclear Engineering and Technology
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• 제36권2호
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• pp.165-174
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• 2004

The distributed resistance model has been recently implemented into the MATRA-LMR code in order to improve its prediction capability over the wire-wrap model for a flow blockage analysis in the LMR. The code capability has been investigated using experimental data observed in the FFM (Fuel Failure Mock-up)-2A and 5B for two typical flow conditions in a blocked channel. The predicted results by the MATRA-LMR with a distributed resistance model agreed well with the experimental data for wire-wrapped subchannels. However, it is suggested that the parameter n in the distributed resistance model needs to be calibrated accurately for a reasonable prediction of the temperature field under a low flow condition. Finally, the analyses of a blockage for the assembly of the KALIMER design are performed. Satisfactory results by the MATRA-LMR code were obtained through and rerified a comparison with results of the SABRE code.

• 전기학회논문지P
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• 제62권1호
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• pp.36-44
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• 2013

This paper is written for the development and application of boiler fuel control algorithm and distributed control system of coal-fired power plant by the steps of design, coding, simulation test, site installation and site commissioning test. Fuel control algorithm has the upper algorithm and it is boiler master control algorithm that controls the fuel, feed water, air by generation output demand. Generation output demand by power load influences fuel control. Because fuel can not be supplied fast to the furnace of boiler, fuel control algorithm was designed adequately to control the steam temperature and to prevent the explosion of boiler. This control algorithms were coded to the control programs of distributed control systems which were developed domestically for the first time. Simulator for coal-fired power plant was used in the test step. After all of distributed control systems were connected to the simulator, the tests of the actual power plant were performed successfully. The reliability was obtained enough to be installed at the actual power plant and all of distributed control systems had been installed at power plant and all signals were connected mutually. Tests for reliability and safety of plant operation were completed successfully and power plant is being operated commercially. It is expected that the project result will contribute to the safe operation of domestic new and retrofit power plants, the self-reliance of coal-fired power plant control technique and overseas business for power plant.

• 한국분말재료학회지
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• 제9권3호
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• pp.189-198
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• 2002

In this work, transient liquid phase (TLP) bonding of Ni-Cr heat resisted cast alloy (HP) was investigated. And also the behaviors of the solid particles distributed in the interlayer during TLP bonding were investigated. The MBF-60 and solid particles (Ni, Fe, and $Al_2O_3$ powders respectively) added MBF-60 which will be a liquid phase coexisting with solid particles at the bonding temperature were used as insert metal. The effective and sound bonding was possible by spark plasma sinter-bonding due to the differences of electric resistance between base metal and liquid insert layer which creates high temperature region. During the isothermal solidification, $Al_2O_3$ particles and solid particles of liquid phase sintered insert metal have shown no growth, while Ni and Fe particles grow rapidly. In this TLP bonding using the MBF-60 and distributed Fe, Ni particles as insert materials, the whole isothermal solidification process was dominated by the growth rate of the solid particles distributed in the interlayer.