• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.538-541
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• 1995

In steel works, reheating furnace is an essential part of a rod mill plant and it treats various types of billets continuously. Although getting an optimal setting for a single billet is simple, control setting for whole groups of billets is a difficult task. In this work, we studied a detail mathematical model and optimal control setting of reheating furnace. As the mathematical model of each billet is a partial differential equation, on-line control is almost impossible for the whole billets charged into the furnace. Therefore, we tried to provide a guideline for optimal setting value of the roof(index) temperature for the target billets which account for about 20% of the charged billets.

• Korean Chemical Engineering Research
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• v.55 no.6
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• pp.767-770
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• 2017

Quadruple tank liquid level systems are popular in testing multivariable control systems for multivariable processes with positive or negative zeros. The liquid level system is nonlinear and it will help to illustrate the robustness of control systems. However, due to nonlinearity, it can be cumbersome to obtain process parameters for testing linear control systems. Perturbation sizes are limited for valid linearized process models, requiring level sensors with high precision. A simple method where the outlet orifice is replaced to a long tube is proposed here. The effluent flow rate becomes proportional to the liquid level due to the friction loss of long tube and the liquid level system shows near linear dynamics. It is applied to the quadruple tank system for easier experiments.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.519-524
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• 2005

A numerical process to simulate SiO2 dry etching with inductively coupled C2F6 plasmas has been constructed using a commercial CFD code as a first step to design a run-to-run control system. The simulator was tuned to reasonably predict the reactive ion etching behavior and used to investigate the effects of plasma operating variables on the etch rate and uniformity. The relationship between the operating variables and the etching characteristics was mathematically modeled through linear regression for future run-to-run control system design.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.5
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• pp.909-915
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• 2022

In this paper, a robot automation technology for chemical tank lorry unloading is presented. Handling chemical coupler between tank lorry and ACQC system may be hazardous or toxic to human operators, therefore robot automation is essential. Due to tight tolerance between couplers, even small pose error may result in very large internal force. In order to resolve the problem, compliance between male and female couplers should be introduced with 6-axis compliance device with F/T sensing. The proposed robot automation system consists of a collaborative robot, 6-ax is compliance device with F/T sensing, linear gripper, and robot vision. The position/force control algorithm and experimental results for assembling chemical couplers are presented.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.560-565
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• 1986

For the control of chemical process, optimal value of the process should be known at first. And process simulation is the previous step of optimal value calculation. However it is not a simple work to analyze chemical process system. Especially for the large scale chemical process system, many difficulties such as non-linearity and complexity caused by recycle streams should be overcome. In this paper, three strategies of large scale chemical process analysis were explained and discussed with case studies.

• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.587-591
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• 2014

Experiments for a control method that enhances the yield to produce high quality red ginsengs have been performed. In the first steaming process of a series of processes to produce red ginsengs from raw ginsengs, there occur several undesirable defects on ginsengs such as cracks of ginseng body, inside cavity and inside white. These defects lead to deterioration in product qualities. Therefore an improved control method that minimizes these undesirable defects is needed in order to increase the yield of high quality red ginsengs. Until these days, the steaming process control methods such as controlling the steaming temperature and/or pressure have been studied. However, such control methods are not adequate enough to minimize the undesirable defects in steamed ginsengs. On the other hand, in this experiment, we suggest a control method that minimizes the undesirable defects through a weight control of steamed ginsengs, keeping the steaming temperature at $96{\sim}99^{\circ}C$ as usual. Experiments with the weight control show that amount of cracks on the steamed ginseng body can be reduced.

• Research in Plant Disease
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• v.15 no.3
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• pp.217-221
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• 2009

Fludioxonil is derived from the antifungal compound pyrrolnitrin produced by Pseudomonas pyrrocinia and classified as a reduced-risk fungicide by the US EPA. The efficacy of fludioxonil for the control of lettuce gray mold caused by Botrytis cinerea was evaluated under several conditions such as growth stages of host, inoculum concentrations, and amounts of potato dextrose broth (PDB) included in spore suspension of B. cinerea. At 4-leaf stage of lettuce plants, fludioxonil applied at 2 ${\mu}g$/ml was more effective for the control of gray mold than at 5- and 6-leaf stages. However, fludioxonil at more than 10 ${\mu}g$/ml provided similar control activity in all growth stages of lettuce tested. The fungicide (10 and 50 ${\mu}g$/ml) also gave excellent control of gray mold on lettuce seedlings inoculated with spore suspensions of B. cinerea ($2.5{\times}10^5$ to $2{\times}10^6$ spores/ml). But, control efficacy of fludioxonil (2 ${\mu}g$/ml) was negatively correlated with inoculum concentration. Addition of PDB in spore suspension of B. cinerea resulted in higher disease severity than non-treated control. By inoculating spore suspension including 0.5% PDB, the fungicide gave the most control activity on the disease, followed by 1% and 2% PDB. The results suggest that fludioxonil has potential to control gray mold of lettuce, but the fungicide at a concentration having moderate activity may represent low control efficacy on the disease under some conditions.

• Bulletin of the Korean Chemical Society
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• v.13 no.4
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• pp.357.2-359
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• 1992

• Journal of Convergence for Information Technology
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• v.12 no.1
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• pp.22-30
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• 2022

In order to prevent chemical accidents caused by human error, a chemical accident prevention and response training program using advanced technology was developed. After designing a virtual process based on the previously built pilot plant, chemical accident response contents were developed. A part of the pilot facility was remodeled for content realization and a remote control function was given. In addition, a DCS program that can control facilities in a virtual environment was developed, and chemical process operator training (OTS) that can finally respond to virtual chemical accidents was developed in conjunction with AR. Through this, trainees can build driving skills by directly operating the device, and by responding to virtual chemical accidents, they can develop emergency response capabilities. If the next-generation OTS like this study is widely distributed in the chemical industry, it is expected to greatly contribute to the prevention of chemical accidents caused by human error.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.1
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• pp.75-77
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• 2002

Stability theorem for nonlinear systems with slowly varying inputs is extended to systems with slowly varying and small jump inputs.