• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.1
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• pp.15-20
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• 2015

Control charts are generally used for process control, but the role of traditional control charts have been limited in case of a non-contaminated process. Traditional ${\bar{x}}$-s control chart has not been activated well for such a problem because of trying to control processes as center line and control limits changed by the contaminated value. This paper suggests modified ${\bar{x}}$-s control chart based on robust estimation. In this paper, we consider the trimmed mean of the sample means and the trimmed mean of the sample standard deviations. By comparing with ARL value, the responding results are decided. The comparison resultant results of traditional control chart and modified control chart are contrasted.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.103-105
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• 2002

Instantaneous following PWM control technique is pulsed nonlinear dynamic control method. This new control technique using analog integrator is proposed to control the duty ratio D of Cuk converter. In this control method, the duty ratio of a switch is exactly equal to or proportional to the control reference in the steady state or in a transient. Proposed control method compensates power source perturbation in one switching cycle, and the average value of the dynamic reference in one switching cycle. There is no steady state error nor dynamic error between the control reference and the average value of the switched variable. Experiments with Cuk converter have demonstrated the robustness of the control method and verified theoretical prediction. The control method is very general and applicable to all type PWM.

• 전기의세계
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• v.21 no.3
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• pp.48-52
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• 1972

The application of pontryagin's Maximum Principle to the optimal control eventually leads to the problem of solving the two point boundary value problem. Most of problems have been related to their own special factors, therfore it is very hard to recommend the best method of deriving their optimal solution among various methods, such as iterative Runge Kutta, analog computer, gradient method, finite difference and successive approximation by piece-wise linearization. The gradient method has been applied to the optimal control of two point boundary value problem in the power systems. The most important thing is to set up some objective function of which the initial value is the function of terminal point. The next procedure is to find out any global minimum value from the objective function which is approaching the zero by means of gradient projection. The algorithm required for this approach in the relevant differential equations by use of the Runge Kutta Method for the computation has been established. The usefulness of this approach is also verified by solving some examples in the paper.

• Journal of Institute of Control, Robotics and Systems
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• v.1 no.1
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• pp.13-19
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• 1995

In this paper, generalized singular value is defined. Using the generalized singular value, robust stability conditions and robust pole placement conditions of structured uncertain systems with star shaped uncertainties are derived. Especially, norm bounded and polytopic uncertainty regions are considered as star shaped uncertainty regions. Linear matrix inequality problems are proposed in order to compute the upper bound of the generalized singular value. The proposed linear matrix inequality problems can be solved by using the convex optimization method.

• Nutritional Sciences
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• v.4 no.2
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• pp.85-90
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• 2001

The purpose of this study was to evaluate the antioxidative potential of Korean wild leaf vegetables in vivo as well as in vitro. The antloxidative activities of Pleurospemum kamtschaticum, Aderophora remotiflor and Aster gfheni were evaluated as a reference for Spinacia oleracea. Fifty rats were find either a control diet or one of several vegetable diets for 4 weeks. The level of thiobarbituric acid reactive substance (TBARS) and the activity of catalase and superoxide dismutase (SOD) in the liver were compared. The levels of total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and triglyceride (TG) in plasma were also compared. Also, the contents of $\beta$-carotene, vitamin C, vitamin E and total phenolic compound, including flavonoid and thiobarbituric acid (TBA) value using linoleic acid model system, were measured in Korean wind leaf vegetables. The TBARS values of Aderophora remotiflor and Aster giheni tended to be lower than that of Spinacia olerncea. The SOD activity of Artrr glheffi was significantly higher than that of Spinacia oleracea and reached 265% that of the control animals, whereas there was no difference between the control animals and the vegetable diet animals in terms of catalase activity. Compared to the control animals, TG and TC levels were significantly solver and showed a lower artheriosclerotic index. TBA values of Pleurospemum Kamschaticum and Aderophora remptiflor were only 18% of control value. TBA value of Spinacia olerucra was 41% of control value. These results suggest that Aderophora remotinor and Aster glheni could have antioxidative potency in vivo as well as in vitro and potential value far functional flood to improve the plasma lipid profile. flavonoid and phenolic compounds could be the major contributing factor in the antioxidative potential of Aderophora remotiflor and Aster glheni.

• Food Science and Preservation
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• v.9 no.3
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• pp.351-355
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• 2002

The purpose of this study was to investigate the nitrite scavenging, eletron donating activity and antioxidant activity of wood vinegar on soybean oil. Wood vinegar was added to soybean oil in the quantities of 0.5, 1 and 5%. Nitrite scavenging effect of all concentrations diminished at higher pH, while in the case of pH 1.2, it showed a nitrite scavenging effect of more than 80% at concentration above of 100 ㎕/mL. The electron donating activity was about 80% at concentration above of 50 ㎕/mL. Soybean oil without the addition of wood vinegar was used as a control. The oxidation of these samples was determined by measuring the peroxide value(POV), thiobarbituric acid(TBA) value and acid value(AV). When wood vinegar was added 1 and 5%, the peroxide value wag lower than both the control and 0.1% BHT. TBA value were in the 5% wood vinegar tallowed by 1% wood vinegar, 0.1% BHT, 0.5% wood vinegar and the control, respectively. The results showed that the acid values were lowest in 5% wood vinegar, followed by the 0.1% BHT, 1% wood vinegar, 0.5% wood vinegar and finally the control.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.378-381
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• 2002

Instantaneous following PWM control technique is pulsed nonlinear dynamic control method. This new control technique using analog integrator is proposed to control the duty ratio D of DC-DC converter. In this control method, the duty ratio of a switch is exactly equal to or proportional to the control reference in the steady state or in a transient. Proposed control method compensates power source perturbation in one switching cycle, and the average value of the dynamic reference in one switching cycle. There is no steady state error nor dynamic error between the control reference and the average value of the switched variable. Experiments with buck converter have demonstrated the robustness of the control method and verified theoretical prediction. The control method is very general and applicable to all type PWM.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.1
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• pp.186-194
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• 1997

The objective of this study is to develope knock control algorithms which can increase engine power without causing frequent knock occurrence. A four cylinder spark-ignition engine is used for the experiments to develop knock control algorithms which use block vibration signals. Knock occurrence is detected accurately by using knock threshold values which consider the difference of transmission path of each cylinder. Spark timing is controlled both simultaneously and individually. With the simultaneous control, torque gain is achieved by retarding the spark timing on knock occurrence in propotion to the knock intensity. The individual knock control algorithm results in higher torque gain than the simultaneous knock control algorithm. The knock occurrence frequency of the individual knock control algorithm is about twice the value of the simultaneous knock control algorithm results. Both control algorithms give similar torque gain of about 3% when they are optimized.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.1
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• pp.151-156
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• 2014

Control charts are generally used for process control, but the role of traditional control charts have been limited in case of a contaminated process. Traditional $\bar{x}$ control charts have not been activated well for such a problem because of trying to control processes as center line and control limits changed by the contaminated value. This paper is to propose robust $\bar{x}$ control charts which is considering a location parameter in order to respond to contaminated process. In this paper, we consider $\bar{x}_{\alpha}$, that is trimmed rate; typically ten percent rate is used. By comparing with p, ARL value, the responding results are decided. The comparison resultant results of proposed two control charts are shown and are well contrasted.

• Journal of the Korean Home Economics Association
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• v.18 no.3
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• pp.5-11
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• 1980

The study carried out to clarify the effects of lard and corn oil on serum total cholesterol content and liver thiobarbituric acid (TBA) value in ethanol (Et-OH) fed mice. Results obtained from the present study were a follows: 1. serum total cholesterol content was considerably increased by 25% Et-OH administration in mice. In case of 25% Et-OH plus Lard group and Lard group both group were also increased significantly to compare with normal value of mice but 25% Et-OH plus lard group was shown very higher value rather than that of Lard group and Lard group was found similar tendency to compare with the 25% Et-OH plus saline group except to after the 1 day. 2. serum total cholestrol content of 25% Et-OH plus Corn oil group and corn oil group were also increased significantly to compare with normal value, but the 25% Et-Oh plus Corn oil group slightly higher level than that of Corn oil group except to after the 3 days. 3. Lard group was also very similar tendency to compare with the corn oil group except to the 3 days. 4. liver TBA value was increased by 25% Et-OH fed mice. 25% Et-OH plus Lard group and Lard group were also increased significantly to compare with liver TBA value in normal mice, but 25% Et-OH plus Lard group was found higher value rather than that of lard group and 25% Et-OH group (Control). Lard group was similar to that of Control group except to after the 1 day. And 25% Et-OH plus Corn oil group was considerably increased rather than that of Control group, and liver TBA value of the above group was similar to that of 25% Et-OH plus Lard group except to after the 3 days. Corn oil group was shown lower value than that of lard group, but it was no significant.