• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2011년도 춘계학술발표대회
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• pp.1074-1077
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• 2011

국내외 대규모 산업시설은 유해물질과 직 간접적으로 밀접하게 관련되어 유해물질 누출사고는 막대한 물적, 인적 피해를 발생시키며 누출물질, 저장시설, 대기 상태에 따라 유해물질 확산 속도 및 범위가 다르기 때문에 이를 예측하는 대기확산 시스템이 필요하다. 또한 기존의 대기확산 시스템은 산업시설 구조물 설계 단계에서 안전성을 확인하는 시뮬레이션용으로 사용되었기 때문에 누출사고 발생 시 즉각적인 처리와 대응이 어려우며 전문적 지식수준의 사용자 입력을 요구한다. 본 논문은 에너지 플랜트 환경의 특수성과 효율성을 고려하여 운영 중인 시설에 적용 가능한 대기확산 시스템 연구를 목적으로 한다. 이를 위하여 신속하고 효율적인 대기확산 모델을 선정 정의하고 융통성 있는 대기확산 시스템의 구성요소를 컴포넌트화하여 구현하였으며 사고 발생 시 빠르게 피해범위를 예측할 수 있는 실시간 대기확산 시스템 설계 방안을 제시하였다.

• 한국표면공학회지
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• 제29권6호
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• pp.648-653
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• 1996

Hydrogenated amorphous carbon(a-C:H) films are prepared by rf plasma CVD in a $CH_4$ source gas system diluted with Ar of $H_2$. The spectra of emissive and reactive species in the plasma are detected using in stiu optical emission spectroscopy. Inaddition, the relationship between the film properties which can be varied by the deposition parameters and the Raman spectra is studied. In the $CH_4/H_2$ gas system, the emission intensities of CH and $H \tau$ decrease and those of $H \alpha$, $H \beta$, $C_2$ and Ar increase with increasing $H_2$ concentration, The formation of $C_2$ and CH in the $CH_4/Ar/H_2$ gas system is greatly suppressed by hydrogen addition and the excess of hydrogen addition is found to form graphite structure. The $C_2$ formation in the gas phase enhances a-C:H film formation.

• Journal of Korean Society for Atmospheric Environment
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• 제23권E2호
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• pp.66-73
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• 2007

The introduction of tracer gas techniques to ventilation studies in indoor environments provides valuable information that used to be unattainable from conventional testing environments. Data acquisition systems (DASs) containing analogue-to-digital (A/D) converters are usually used to function the key role that records signals to storage in digital format. In the testing process, there exist a number of components in the measuring equipment which may produce system-based inference to the monitored results. These unwanted fluctuations may cause significant error in data analysis, especially when non-linear algorithms are involved. In this study, a pre-processor is developed and applied to separate the unwanted fluctuations (noise or interference) in raw measurements and to reduce the uncertainty in the measurement. Moving average, notch filter, FIR (Finite Impulse Response) filters, and IIR (Infinite Impulse Response) filters are designed and applied to collect the desired information from the raw measurements. Tracer gas concentrations are monitored during leakage and ventilation tests in the model test room. The signal analysis functions are introduced to carry out the digital signal processing (DSP) work. Overall the FIR filters process the $CO_2$ measurement properly for ventilation rate and mean age of air calculations. It is found that, the Kaiser filter was the most applicable digital filter for pre-processing the tracer gas measurements. Although the IIR filters help to reduce the random noise in the data, they cause considerable changes to the filtered data, which is not desirable.

• 대한기계학회논문집A
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• 제20권9호
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• pp.2760-2769
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• 1996

The feedback control systems of welding process using visual information can improve weld qualities. However, it is very difficult to get the visual information of weld pool since the light intensity of welding arc is much stronger than that of the weld pool. To explore the possibility of extending the capability of automatic welding machines, a study of a closed loop controlled welding system consisted of a GTA welding machine, a vision system, a stepping motor system and a digital computer was undertaken. Particularly, in this system, a CCD camera with a long wavelength pass filter was used to get a better weld pool image. Subsequently, an image analysis technique has been developed to measure the weld pool width. Using this weld pool width measurement, a colsed loop control system adjusted welding speed to maintain a constant weld pool width.

• 융합신호처리학회논문지
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• 제7권3호
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• pp.149-154
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• 2006

본 논문에서는 온도제어에 있어서 수동식 로온도 제어 전문가의 행위와 유사한 결과를 나타낼 수 있도록 퍼지 제어 룰과 퍼지 변수 및 퍼지 추론 등을 이용하여 밸브의 Gas-to-Air 비율을 조절하는 적응 퍼지 제어기를 설계하였다. 이를 적용한 가스로 자동온도조절 시스템을 개발하고 온도와 소결된 세라믹 시료의 불량률 평가를 통해 그 성능이 우수함을 확인하였다. 적응 퍼지 제어를 이용한 제안 시스템의 온도오차의 경우 학습 전은 약 ${\pm}20^{\circ}C$ 이상 생기던 것이 학습 후에는 ${\pm}2^{\circ}C$ 내외로써 입력 온도 프로파일을 우수하게 추종해 냄을 확인할 수 있었다. 또한 기존 수동로 시스템과 제안된 시스템 간에 세라믹 제품 소결 후의 불량률을 비교하기 위해 시료 A와 B에 대해 각각 두 번에 걸쳐 실험하였다. 불량률을 확 인한 결과 개선효과가 시료 A와 시료 B에 대해 각각 평균 50.5% 와 48.4%로 상당히 좋아짐을 확인하였다.

• Journal of Mechanical Science and Technology
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• 제18권3호
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• pp.370-378
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• 2004

An autonomous pipeline inspection gauge system has been developed for determining position, orientation, curvature, and deformations such as dents and wrinkles of operating pipelines by Korea Gas Company and Seoul National University. The most important part of several subsystems is the Strapdown Inertial Measurement Unit (SIMU), which is integrated with velocity and distance sensors, weld detection system, and digital recording device. The Geometry Pipeline Inspection Gauge (GeoPIG) is designed to operate continuously and autonomously for a week or longer in operating gas pipelines. In this paper, the design concepts, system integration, and data processing/analysis method for the PIG will be presented. Results from the recent experiment for a 58 kilometer gas pipeline will be discussed.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
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• pp.309-312
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• 2001

A primitive gas classification system which can classify limited species of gas was designed and simulated. The 'electronic nose' consists of an array of 4 metal oxide gas sensors with different selectivity patterns, signal collecting unit and a signal pattern recognition and decision Part in PLD(programmable logic device) chip. Sensor array consists of four commercial, tin oxide based, semiconductor type gas sensors. BP(back propagation) neutral networks with MLP(Multilayer Perceptron) structure was designed and implemented on CPLD of fifty thousand gate level chip by VHDL language for processing the input signals from 4 gas sensors and qualification of gases in air. The network contained four input units, one hidden layer with 4 neurons and output with 4 regular neurons. The 'electronic nose' system was successfully classified 4 kinds of industrial gases in computer simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1322-1324
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• 2002

For developing a 100 kW MCFC power generation system, Several design parameters for a fuel cell stack and system analysis results by Cycle Tempo, a processing computer soft ware, were described. Approximately 170 cells are required to generate 100 kW at a current density of 125 mA/$cm^2$ with 6000 $cm^2$ cells. An overall heat balance was calculated to predict exit temperature. The 100 kW power is expected only under pressurized operation condition at 3 atm. Recycle of cathode gas by more than 50% is recommended to run the stack at 125 mA/$cm^2$ and 3 atm. Manifolds should be designed based on gas flow rates for the suggested operating condition. The fuel cell power generation system was designed conceptually with several choices of utilization of anode exhaust gas. Also system efficiency was calculated at various type of system and operation conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1300-1302
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• 2001

For developing a 100 kW MCFC power generation system. Several design parameters for a fuel cell stack and system analysis results by Cycle Tempo, a processing computer soft ware, were described. Approximately 170 cells are required to generate 100 kW at a current density of $125mA/cm^2$ with $6000cm^2$ cells. An overall heat balance was calculated to predict exit temperature. The 100 kW power is expected only under pressurized operation condition at 3 atm. Recycle of cathode gas by more than 50% is recommended to run the stack at $125mA/cm^2$ and 3 atm. Manifolds should be designed based on gas flow rates for the suggested operating condition. The fuel cell power generation system was designed conceptually with several choices of utilization of anode exhaust gas. Also system efficiency was calculated at various type of system and operation conditions.

• Journal of Advanced Marine Engineering and Technology
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• 제33권7호
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• pp.1003-1011
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• 2009

This study aims at precise control of oil outlet temperature in the oil cooler system of machine tools for enhancement of working speed and processing accuracy. PID control logic is adopted to obtain desired oil outlet temperature of the oil cooler system with hot-gas bypass method. We showed that the gains of PID controller could be easily determined by using gain tuning methods to get the gain of PID controller without any mathematical model. We also investigated various gain tuning methods to design the gains of PID and compared each control performance for selecting the optimal tuning method on the hot gas bypass method through experiments. Moreover, we confirmed excellent control performance with proposed PI controller gain even though disturbances were abruptly added to the experimental system.