• Journal of Pharmacopuncture
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• v.3 no.2
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• pp.99-130
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• 2000

This study was carried out to investigate the effects of Liriopis Tuber Herbal-Acupuncture on Diabetes Mellitus induced by streptozotocin in rat. Body weight, serum insulin, glucose, triglyceride, HDL cholesterol, free cholesterol and total protein were measured in streptozotocin induced diabetic rat injected with Liriopis Tuber Herbal-Acupuncture solution at Pisu(BL20) respectively for 30 days. In order to study the effects of Liriopis Tuber Herbal-Acupuncture at Pisu(BL20) on Diabetes Mellitus induced by Streptozotocin in rat, The groups were divided into five groups; Normal group(non treated group), N.-Saline group(administration of injection with normal saline at BL20 in 30 days after streptozotocin injection), Control group(non treated group after streptozotocin injection), H. Acup. group (administration of Liriopis Tuber Herbal-Acupuncture at BL20 in 30 days after streptozotocin injection), and Acup. group (administration of acupuncture at BL20 in 30 days after streptozotocin injection). The results obtained were summarized as follows; 1. As compared with Control group, there wae no significant tendency to diminish the rate of weight loss in H. - Acup. group. 2. As compared with Control group, there wae signiticant increase of serum insulin level in H. -Acup. group. 3. As compared with Control group, there was decrease of glucose level in H.- Acup. group. 4. As compared with Control group, there was decrease of triglyceride level in H. - Acup. group. 5. As compared with Control group, trere wae increase of HDL cholesterol level in H. - Acup. group. 6. As compared with Control group, there was significant increase of free cholesterol level in H. - Acup. group. 7. As compared with Control group, there was Increase of total protein level in H. - Acup. group. According to above mentioned results, Liriopis Tuber Herbal-Acupuncture was expected to be effective in treatment of Diabetes Mellitus and its complications.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1997.06c
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• pp.89-98
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• 1997

This study was conducted to develop an automatic nutrient-solution control system for small-scale growers. The nutrient-solution control system consisted of a low-cost and precise metering device and a personal computer. The system controlled electric conductivity(EC) and pH of nutrient-solution based on the time-based feedback control method with the information about temperature, EC, and pH of the nutrient-soIution. The performance of the nutrient-solution control system was evaluated through the control of EC and pH while compared with those of commercial nutrient-solution control system. Also an experimental cultivation of tomato was conducted to verify and to improve the developed system. Results of this study were as follows. 1. An automatic nutrient-solution control system based on a low-cost and precise metering device was developed. 2. The developed system controlled EC and pH within $\pm$0.05 mS/cm and $\pm$0.2 pH full scale error respectively at $24^{/circ}C$. 3. When using the commercial system, the controlled values of EC and pH of the 500l of water were 1.29 mS/cm and 6.1 pH for the setting points of 1.4 mS/cm and 6.0 pH respectively at $22^{/circ}C$. 4. The developed nutrient-solution control system showed $\pm$0.05 mS/cm of deviation from the setting EC value over the experimental cultivation period. 5. The deviation from the average values of Ca and Mg mass content in the several nutrient-solution were 0.5% and 1.8% respectively.

• Transactions of The Korea Fluid Power Systems Society
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• v.3 no.2
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• pp.14-20
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• 2006

A controller design procedure for an electro-hydraulic positioning systems has been developed using $H{\infty}$ control. The generalized plant models and weighting function for multiplicative uncertainty modelling error was presented along with $H{\infty}$ controller designs in order to investigate the robust stability and performance. Both disturbance rejection and command tracking performances were improved with the $H{\infty}$ controller, and the better uniformity of time response is achieved across wide range of operating conditions than the PID, LQR and LQG control scheme. The multiplicative uncertainty case was specifically suited for the design of an electro-hydraulic positioning control systems using $H{\infty}$ control.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.391-395
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• 1996

This paper presents a robust force tracking control of a small-sized SMA gripper with two fingers using shape memory alloy(SMA) actuators. The mathematical governing equation of the proposed system is derived by Hamilton's principle and Lagrangian equation and then, the control system model is integrated with the first-order actuator dynamics. Uncertain system parameters such as time constant of the actuators are also included in the control model. A robust two degree of freedom(TDF) controller using H$_{\infty}$ control theory, which has inherent robustness to model uncertainties and external disturbances, is adopted to achieve end-point force tracking control of the two-finger gripper. Force tracking control performances for desired trajectories represented by sinusoidal and step functions are evaluated by undertaking both simulation and experimental works.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2002.11a
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• pp.339-342
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• 2002

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 H$_{\infty}$ controller was designed. In this paper, H$_{\infty}$ control of 2-mass system using H$_{\infty}$ filter for compensating shaft torque is proposed. Pole-zero maps show the validity of proposed controller.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.2
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• pp.190-196
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• 2013

It presents a unification of buck-boost and flyback converter for driving a cascaded H-bridge multilevel inverter with a single independent DC voltage source. Cascaded H-bridge multilevel inverter is useful to make many output voltage levels for sinusoidal waveform by combining two or more H-bridge modules. However, each H-bridge module needs an independent DC voltage source to generate multi levels in an output voltage. This topological characteristic brings a demerit of increasing the number of independent DC voltage sources when it needs to increase the number of output voltage levels. To solve this problem, we propose a converter combining a buck-boost converter with a flyback converter. The proposed converter provides independent DC voltage sources at back-end two H-bridge modules. After analyzing theoretical operation of the circuit topology, the validity of the proposed approach is verified by computer-aided simulations using PSIM and experiments.

• Journal of Environmental Science International
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• v.32 no.2
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• pp.139-143
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• 2023

The effects of essential oils on pH, pathogens, and volatile fatty acids (VFA) in two poultry litters were investigated through a lab study. Essential oil-added poultry litters were randomly divided to two groups: control (200 g poultry litter) and Treatment (50 g thymol/Briefly, 200 g broiler litter was treated with or without 50 g thymol (Control and T1, respectively; 1 groups) and 200 g duck litter was treated with or without 50 g carvacrol (Control and T2, respectively; 2 group). Adding thymol to broiler litter increased the pH, reduced pathogens, and did not affect VFA. Interestingly, adding carvacrol slightly reduced the pH of duck litter, but had no significant effect on reducing pathogens and VFA. This difference is probably because the essential oil used and the properties of the two litters are different. In addition, pH was thought to control the odor generated from the litter, but this has not been proven. Further field studies should focus on clarifying this point.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.6
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• pp.794-800
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• 2004

The purpose of this study is to propose a method of controlling freshwater algae which grows abundantly and forms water bloom in the eutrophic water body with $H_2O_2$. Both laboratory and field methodologies were used. For the laboratory test $H_2O_2$ was injected into the different growth phases of incubated Microcystis aeruginosa and the resulting algae growth control rate was examined. For the field test, $H_2O_2$ was dispersed into a lake. Lake water quality was evaluated using a pre-test and post-test analysis of chlorophyll-a, luminance, transmittance, etc., which allowed a comparative evaluation of water quality change. From the experimental results, the growth of algae can be controlled with the small amount of 1mg/L of $H_2O_2$ at the lag phase of growth. The field test results show that the green colour of lake water was removed completely by the reduction of chlorophyll-a and improved transmittance, luminance, TKN, TP, TOC and SS. These indicators of water quality were improved significantly after $H_2O_2$ injection. Toxicity test results using the lake fish show no evidence of detrimental effect of $H_2O_2$ up to 15mg/L. The results of $EC_{50}$ with P. phosphoreum show that the toxicity of $H_2O_2$ was negligible compared to copper which was commonly used for algae control.

• Journal of Microbiology and Biotechnology
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• v.22 no.2
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• pp.220-225
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• 2012

In batch culture for Poly(vinyl alcohol) (PVA)-degrading enzyme (PVAase) production by a mixed culture, higher pH (pH 7.5) was favorable for PVAase production at the prophase of cultivation, but lower pH (pH 7.0) was favorable at the anaphase. This situation was caused by the fact that the optimum pH for different key enzymes [PVA dehydrogenase (PVADH) and oxidized PVA hydrolase (OPH)] production is various. The activity and average specific production rate of PVADH reached the highest values at constant pH 7.5, whereas those of OPH appeared at pH 7.0. A two-stage pH control strategy was therefore developed and compared for its potential in improving PVAase production. By using this strategy, the maximal PVAase activity reached 2.05 U/ml, which increased by 15.2% and 24.2% over the fermentation at constant pH 7.5 and 7.0.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.11
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• pp.1556-1561
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• 2011

The purpose of this study was to investigate antioxidant enzyme activity and vitamin E concentrationin in Sprague-Dawley rat after being fed various extracts of Hizikia fusiforme. There were six experimental groups: control group (C), H. fusiforme ethanol extract group (EtOH), H. fusiforme dichloromethane fraction group ($CH_2Cl_2$), H. fusiforme ethylacetate fraction group (EtOAc), H. fusiforme butanol fraction group (n-BuOH), H. fusiforme water fraction group ($H_2O$). H. fusiforme extracts (400 mg/kg B.W) were orally administrated to the rats every day for 4 weeks. The activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px), and concentrations of malondialdehyde (MDA) and vitamin E in the liver and blood were measured. The activity of SOD in the liver was significantly higher in the $CH_2Cl_2$ and $H_2O$ groups (p<0.05) than in the control and other extract groups. The SOD activity in serum increased significantly in all H. fusiforme groups (p<0.05) compared to the control group and it was also significantly higher in the EtOH and $H_2O$ groups (p<0.05) than in other extract groups. The serum catalase activity increased significantly in the n-BuOH group (p<0.05) compared to the control and other extract groups. The plasma MDA concentration decreased significantly in the n-BuOH and $H_2O$ group (p<0.05) compared to the control group. Serum concentration of ${\alpha}$-tocopherol showed no significant differences in most of the experimental groups, but it was significantly higher in the EtOAc group (p<0.05). The ${\alpha}$-tocopherol concentrations in the liver showed a significant increase in the $CH_2Cl_2$ and $H_2O$ groups (p<0.05) compared to the control and other extract groups. The liver ${\gamma}$-tocopherol concentrations in H. fusiforme extract groups showed a tendency to increase compared to the control group and it was significantly higher in the $H_2O$ group (p<0.05) than in other extract groups. These results suggest that supplementation of water extracts of H. fusiforme extract could be effective in improving the antioxidant system.