• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.5
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• pp.632-637
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• 2005

This study has been carried out to understand the effect of Hovenia dulcis on the hyperglycemic mice induced with streptozotocin (STZ). Mice in control group were administered with $0.9\%$ saline (2 mL/kg), and experimental groups were administered Hovenia dulcis extract (H1 group, 0.01 g/kg: H2 group, 0.04 g/kg) after hyperglycemic state was induced. Blood glucose concentrations of tile H1 and H2 groups administered with Hovenia dulcis extract for 6 weeks were significantly (p<0.01), compared to control group. Blood glucose tolerance was more favorable in H1 and H2 groups than control group. The Langerhan's islet of pancreas was destructed by treatment of STZ in the control group, but pancreatic islet of the experimental groups was partially recovered from damage, and a number of insulin-positive cells were observed. A number of insulin-like growth factor- I and II (IGF-I and IGF-II) positive cells occurred in the acinar cells of H1 and H2 groups. These results suggest that administration of Hovenia dulcis extract help mice recover from the damage induced with STZ.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.2
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• pp.329-339
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• 2002

In ship operation the consequency of roll motions can seriously degrade the performance of mechanical and personnel effectiveness. So many studies for the roll stabilization control system design have been performed and very good results have been achieved. In many studies, the stabilizing fins are used. Recently rudders, which have been extensively modified, have been used to exclusively to stabilize the roll. This paper examines the two-degree-of-freedom servosystem design technique to synthesize the yaw control system which achieves the course keeping object of the ship and the H$_{\infty}$ control approach to suppress the roll motion, respectively.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3073-3076
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• 1999

In this paper, $H_{\infty}$ two-degree-of freedom(2-DOF) model following control method is applied for the control of a brushless servo motor to achieve high robust performance. The proposed robust control algorithm designed to meet the robust stability and performances present that the robust control method is superior to conventional control methods in controlling the speed and position of a servo motor. The designed controller is implemented as an outer loop controller to a factory designed motor-servopack system. It is illustrated by simulations that the proposed method is effective to control servo systems.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.4
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• pp.276-284
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• 2000

In this paper, the genetic algorithm is used to design a mixed H₂/ H/sub ∞/ controller Two kinds of controller forms, Youla's form and the general form, are considered to design a mixed H₂/ H/sub ∞/ controller. Efficient searching methods are sought to minimize the given H₂cost function under the H∞ constraint. It is verified by an example that the developed algorithm can provide stable results in the region where unstable results are shown by the conventional gradient method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.2
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• pp.156-160
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• 2020

Emergence and early growth changes of stratification condition of tea (Camellia sinensis) seeds were investigated in 7 treatments (control, pH 4, pH 10, 70% ethanol (EtOH), 10 mM H₂O₂, 100 mM H₂O₂, and physical shock (5.9 J)). Ethanol treatment was toxic and did not induce emergence. The emergence rate was 36.7% in the control, 26.7% under pH 10, 46.7% under pH 4, 48.3% under physical shock, 51.7% under 10 mM H₂O₂, and 65.0% under 100 mM H₂O₂ treatments. It was higher by approximately 178% in the H₂O₂ treatment as compared to the control. Plant height was 6.5 cm in the control, 6.6 cm under pH 10, 7.6 cm under pH 4, 7.8 cm under physical shock, 8.3 cm under 10 mM H₂O₂, and 9.1 cm under 100 mM H₂O₂ treatments. Leaf length and leaf width were also higher under the H₂O₂ treatment. Therefore, hydrogen peroxide treatment induced emergence and increased the uniformity of early growth.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.231-233
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• 1994

We have studied a properly of N-docosyl pyridinium(TCNQ) Langmuir-Blodgett film at room temperature with the $NO_2$ gas-detection characteristics. As a result, we have found that their conductivities were increased by 6 times at 5 layers(about $250{\AA}$ thickness) LB film. However, their reproducibility was not able to be measured at room temperature. Therefore, we must find their working temperature which was able to activate gas-detection characteristics. The $NO_2$ gas response experiments under 200 ppm concentration in $50^{\circ}C$ show that :here are increment of electrical conductivity by 8 times and 100 seconds of response time, and 200 seconds of recovery times at $60^{\circ}C$.

• Proceedings of the KIEE Conference
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• 2001.07e
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• pp.53-57
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• 2001

In the industrial motor drive system which is composed of a motor and load connected with a flexible shaft, a torsional vibration is often generated because of the elastic elements in torque transmission. To solve this problem, the two degrees of freedom $H_{\infty}$ controller was designed. But it is difficult to realize that controller. In this paper, $H_{\infty}$ control of 2-mass system using partial state feedback and resonance ratio control is proposed. Proposed controller has simple structure but satisfies the attenuation of disturbances and vibrations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.316-321
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• 2007

[ $H{\infty}$ ] controller, which shows robustness for disturbances and noises, can not be used in the case of uncertain system parameters. Even if the $H{\infty}$ controller can be designed for the parameter uncertain system, its performance can be deteriorated. Therefore, in this paper, the robustness of $H{\infty}$ controller is improved by using the SMC(Sliding Mode Control). The LMI based $H{\infty}$ controller is designed first and then SMC controller is added.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.515-517
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• 1997

In the industrial motor drive system, a shaft torsional vibration is often generated when a motor and a load are connected with a flexible shaft. This paper treats the vibration suppression control of such a system. In this paper, two-degree-of-freedom(TDOF) control of the two-mass resonant system using the $H_{\infty}$ filter is proposed. TDOF control method satisfies the command following property and the internal stability at the same. The $H_{\infty}$ filter is robust in noise and disturbance. Simulation results show the validity of the proposed control method.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.828-833
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• 2004

The performance of a mixed $H_{\infty}/H_2$ design with pole placement constraints based on robust vibration control for a piezo/beam system is investigated. The governing equation of motion for the piezo/beam system is derived by Hamilton's principle. The assumed mode method is used to discretize the governing equation into a set of ordinary differential equation. A robust controller is designed by $H_{\infty}/H_2$ feedback control law that satisfies additional constraints on the closed-loop pole location in the face of model uncertainties, which are derived for a general class of convex regions of the complex plane. These constraints are expressed in terms of linear matrix inequalities (LMIs) approach for the multiobjective synthesis. The validity and applicability of this approach for vibration suppressions of SMART structural systems are discussed by damping out the multiple vibrational modes of the piezo/beam system.