• Proceedings of the Korean Institute of Surface Engineering Conference
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• 한국표면공학회 2002년도 춘계학술발표회 초록집
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• pp.10-11
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• 2002

• Journal of the Korean Institute of Gas
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• 제9권3호
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• pp.38-43
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• 2005

There is monitored amount operation variables and controlled by operating conditions and loads at many facilities using gas also chemical plants. The process fault which can be indicated by operators, is occurred when the abnormal state was accumulated continuously owing to physical failure, external disturbance or human error. This is studied a Early Warning System which is to estimate process status by real-time monitoring operation variables and to early warning before it will be occurred process fault.

• Journal of the Korean Institute of Gas
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• 제19권6호
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• pp.99-104
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• 2015

Today the most efficient way to transport the natural gas is carried via the liquid. In order to liquefy the natural gas to be cooled to $-160^{\circ}C$ or less. Cooling method has a number of different ways. In this paper, we studied control method for the representative liquefaction process, C3MR. Natural gas liquefaction control is a tool that can maintain the quality of natural gas is a means to ensure stable operation. Analyzing the C3MR process, and select the control parameters for the control valve. We find control structure for mixed refrigerant cycle through the step response. A control result obtained through the dynamic simulation arbitrarily given a disturbance was found to maintain a steady-state results.

• Composites Research
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• 제37권4호
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• pp.275-285
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• 2024

This paper presents research trends in predicting the deformation of carbon fiber reinforced thermoplastic (CFRTP) composites during thermoforming. Various thermoforming variables that must be considered during the CFRTP thermoforming stages are investigated, and factors influencing process-induced deformation are analyzed. Key material behavior models, such as crystallinity and viscoelastic, which are important for predicting thermoforming deformation, are also examined. Additionally, trends in predicting CFRTP thermoforming deformation using finite element analysis with material behavior models and machine learning techniques are analyzed. In summary, more precise prediction techniques for thermoforming deformation can be developed by associating them with material behavior models and considering thermoforming variables.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제13권3호
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• pp.961-966
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• 2012

The concern about vacuum glass is enhanced as society gets greener and becomes more concerned about energy savings due to the rising cost of oil. The glass edge sealing process needs the high reliability among the main process for the vacuum glass development in order to maintain between the two glass by the vacuum. In this paper, the process of the edge sealing was performed by using the hydrogen mixture gas which is the high density heat source unlike the traditional method glass edge sealing by using the frit as the soldering process. The ambient temperature in the electric furnace was set in the edge sealing to prevents the thermal impact and transformation of the glasses and the temperature distribution uniformity was measured. The parameter of the edge sealing was set through the basic test and the mathematical relation with the area of the glass edge parts according to the parameter was drawn using the multiple regression analysis method.

• Composites Research
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• 제33권6호
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• pp.390-394
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• 2020

The carbon fiber has been damaged via tow spreading process for carbon fiber spread tow. The fiber damage is caused by friction between equipment and fibers or between fibers and fibers in the process of spreading. As a result, mechanical properties are decreased due to differences in process via material and equipment condition. Therefore, minimizing fiber damage have to be considered in the process. In this study, the change in carbon fiber pneumatic spreading process was observed by according to the filament count, sizing content of carbon fiber and process variables in spreading equipment (fiber tension at the beginning, air temperature in spreading zone, vacuum pressure in spreading zone). Tensile strength was evaluated using samples prepared under optimal conditions for each of the carbon fiber varieties, and mechanical properties were reduced due to damage on the carbon fiber.

• Journal of Korea Fair Competition Federation
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• 79호
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• pp.11-19
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• 2002

공정거래 위반사건은 다른 위반행위와 같이 단순히 법률 문구의 해석을 통해 위법성 여부를 판단할 수 있는 성격의 것이 아니다. 공정거래사건의 위법성 판단을 위해서는 유기체처럼 살아 움직이는 다양한 시장을 일정하게 정해 놓고 그 시장에 대하여 경쟁보호의 관점에서 종합적이고도 다각적으로 분석할 필요가 있기 때문이다. 즉 공정거래사건은 단순히 행위 그 자체만을 가지고 위법성 여부를 판단하기는 어렵고, 그 행위와 관련된 시장에서의 제품 및 그 원료의 생산$\cdot$유통$\cdot$판매$\cdot$소비, 업종의 특성, 해외수입 등 다양한 변수들을 분석하여 현재의 시장상황은 물론 향후 예상되는 시장상황까지 고려하여 판단할 수 있는 고도의 전문적이고 치밀한 작업이 요구되는 것이다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 한국대기환경학회 2000년도 추계학술대회 논문집
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• pp.249-250
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• 2000

최근에 환경 오염물질의 제거를 위한 코로나 방전기술이 큰 관심을 끌고 있으며 재래적인 기술들을 능가하는 여러 가지 장점으로 인해 강도 높은 연구들이 이루어지고 있다. 전기방전을 이용하는 공정에서 방전특성은 공정의 효율과 에너지 소모량에 중요한 영향을 미친다. 공정에 따라서 요구되는 방전특성이 다르며, 효율적인 공정이 되기 위해서는 최적의 방전특성에 대한 규명이 이루어져야 한다. 방전에 의해 생성되는 플라즈마 상태는 공정의 전기적 변수들, 반응기의 기하학적 형태, 유입기체의 조성 등 다양한 요소들에 의해 영향을 받으므로 특성에 대한 규명이 매우 어렵다. (중략)

• Korean Chemical Engineering Research
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• 제45권1호
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• pp.32-38
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• 2007

A batch Process has a multi-way data structure that consists of batch-time-variable axis, so the statistical modeling of a batch process is a difficult and challenging issue to the process engineers. In this study, We applied a statistical process control technique to the general batch process data, and implemented a fault-detection and Statistical process control system that was able to detect, identify and diagnose the fault. Semiconductor etch process and semi-batch styrene-butadiene rubber process data are used to case study. Before the modeling, we pre-processed the data using the multi-way unfolding technique to decompose the data structure. Multivariate regression techniques like support vector regression and partial least squares were used to identify the relation between the process variables and process condition. Finally, we constructed the root mean squared error chart and variable contribution chart to diagnose the faults.

• Journal of Korean Society of Environmental Engineers
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• 제22권7호
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• pp.1273-1284
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• 2000

In this study, ultrafiltration was performed to remove humic acid from aqueous solution. Since the effects of system variables on the ultrafiltration were tangled with non-linearly. Response Surface Methodology(RSM) was used to know optimum conditions of ultrafiltration process, relations among system variables, and the effects of system variables such as pressure difference across the membrane, concentration of humic acid, and feed flow rates. As concentrations of humic acid were 10ppm, 40ppm, and 70ppm in feed stream, permeation fluxes were 2.56, 2.27, and $2.10({\times}10^{-2}cc/cm^2{\cdot}min)$ respectively ; in other words, permeation fluxes of 10ppm, 40ppm and 70ppm feed concentration decreased by 17.7%, 26.7% and 32.2% of pure water permeation flux respectively. Concentration of humic acid in permeate side were 0.5ppm, 1.2 ppm, and 2.1ppm respectively. When pressure difference(${\Delta}P$) increased from 1atm to 2atm and 3atm, permeation fluxes of 40ppm feed concentration increased by 66% and 152% of permeation rate at 1atm respectively. However, concentrations of humic acid in permeate side increased from 0.5ppm to 1.5ppm and 3.5ppm. RSM showed that the optimum condition of system variables is 38.5~40ppm of humic acid concentration in feed stream, 30~30.7cc/min of feed flow rate, and 2atm of pressure difference.