• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.5
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• pp.503-510
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• 2011

This paper presents a method of optimizing the blade pitch and generator torque controllers which have been already designed for an existing wind turbine generator system. Since the highly nonlinear and uncertain characteristics of the wind turbine generator can not be fully considered in the controller design phase, some parameters such as control gains must be tuned during the field implementation phase. In this paper, nonlinear simulation software, which is based high fidelity wind turbine model, and optimization technique are effectively combined and used to tune a set of gains for the blade pitch and the generator torque controllers. Simulation results show that the baseline controllers can be effectively optimized to reduce the errors in wind turbine rotor speed and generator power output controls as well as twisting of the high and low speed shafts.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.8
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• pp.691-701
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• 2017

The barbell squat is a fundamental physical exercise for strengthening the lower body and core muscles. It is an integral part of training and conditioning programs in sports, rehabilitation, and fitness. In this paper, we proposed a virtual test framework for squat exercises using a Smith machine to simulate joint torques and muscle forces, based on an integrated product-human model and motion synthesis algorithms. We built a muscular skeletal human model with boundary conditions modeling the interactions between the human body and a machine or the ground. To validate the model, EMG, external forces, and squat motions were captured through physical experiments by varying the foot position. A regression-based motion synthesis algorithm was developed based on the captured squat motions to generate a new motion for a given foot position. The proposed approach is expected to reduce the need for physical experiments in the development of training programs.

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.55-60
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• 2020

As research and development of eco-friendly vehicles are expanding worldwide, additional devices of vehicles are reduced or deleted to increase the mileage, or research is being conducted to reduce weight. Among them, the multi-stage transmission that was applied to the internal combustion engine vehicle was deleted and replaced with a reducer, and the initial driving power is secured by increasing the torque through the control of the motor output value. However, since frequent motor speed change can result in a load increase, this study attempts to develop a compact and lightweight manual two-stage reducer with a general reducer structure. Therefore, a two-speed transmission with two gear ratio was designed by inserting a large gear and a small gear in a structure with a parallel shaft to connect the gears with a V-belt in the form of a parallel shaft reducer, and setting the gear ratio of the low and high gears respectively. In addition, power performance according to the rotational speed and load of the transmission was checked through a test, and the heat generation characteristics generated during driving were checked to verify the validity of the transmission.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.2
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• pp.181-189
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• 2005

The purpose of this study was to investigate the relationship between obesity indices, nutritional knowledge, nutritional intake status, and some blood parameters in obese middle-school students. Anthropometric measurement, 24-hour recall for dietary intake, blood analysis and Questionnaire response including nutritional knowledge, nutritional attitude, and self-satisfaction were conducted in 42 obese middle-school students (28 male and 14 female) participated in the nutritional camp program carried by Bucheon district public health center in Kyunggi-do. The mean age of subjects was 13.9 years. The average body weight, BMI, obesity index, WHR and percent body fat were 75.5 kg, 29.1 kg/$m^2$, 30.1, 0.89 and 33.3% in male subjects, and 67.8 kg, 27.5 kg/$m^2$, 25.3, 0.81 and 34.6% in female subjects. The average nutritional attitude, the self-satisfaction and the nutritional knowledge scores were no significant difference between male and female subjects. Average intake of energy were 85.5% of RDA in males and 98.1% of RDA in females. The percentage of energy from fat was higher in both male (29%) and female (26%) subjects than recommended level. Calcium, iron, zinc, vitamin A, vitamin B$_2$, vitamin C, niacin and folate intakes were below the RDA for them. In the results of correlation analysis, body weight, BMI and obesity index were positively correlated with systolic blood pressure and cholesterol intake. There was a negative correlation between percent body fat and nutritional knowledge. Body weight was negatively related to HDL-cholesterol, whereas it has positive relation with RBC, hemoglobin and hematocrit. BMI and obesity index were negatively related to HDL-cholesterol, but positively related to RBC, respectively. WHR showed positive relationship with serum GPT, glucose and MCV.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.2
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• pp.151-155
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• 2017

Purpose: The aim of this study was to evaluate screw removal torque of the two-piece zirconia abutment with the novel titanium component compared to the conventional one-piece titanium abutment in the internal connection implant before and after dynamic cyclic loading. Materials and methods: Two types of the abutment assemblies with internal connection were prepared and divided into the groups; titanium abutment-titanium abutment screw assemblies as control, and zirconia abutment-titanium socket-titanium abutment screw assemblies as experimental group. A total of 12 abutments and implants were used of six assemblies each group. Each assembly was tightened to 30 Ncm. A cyclic load of 300 N at an angle of 30 degrees in reference to the loading axis was applied until one million cycles or failure. The removal torque values (RTVs) of the abutment screws were measured with a digital torque gauge before and after cyclic loading. The RTVs of the pre load and post load were analyzed with t-test, and P-values < .05 were considered statistically significant. Results: The assemblies of both groups survived all after the dynamic cyclic loading test without screw loosening. The statistically significant differences were found between the mean RTVs before and after the cyclic loading in both groups (P < .05). The RTV differences for the control and the experimental group were $-7.25{\pm}1.50Ncm$ and $-7.33{\pm}0.93Ncm$, respectively. Statistical analysis revealed that the RTV differences in both groups were not significantly different from each other (P > .05). Conclusion: Within the limitation of this study, the two-piece zirconia abutment with the titanium component did not show a significant RTV difference of the abutment screw compared to the titanium abutment after dynamic cyclic loading.

• Journal of fish pathology
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• v.20 no.3
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• pp.269-279
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• 2007

This study was conducted to investigate the change of antioxidant enzyme activity (catalase and superoxide dismutase) and variation of blood physiology in olive flounder (Paralyticus olivaceus) by hydrogen peroxide (H2O2) treatment. Blood parameters were measured 1, 3 and 5 hours after H2O2 treatment with 0 (control), 100, 300 and 500 ppm for 1 hr. The value of hematocrit was decreased significantly dependently on treatment concentrate and elapsed time in the treatment of H2O2. Hemoglobin concentration in the test groups were lower than that of the control group. Red blood cell value in the test groups were significantly lower compared to that of the control group, but recovered to the level of the control group after 5 hr. Protein concentration was significantly lower compared to that of the control group at 0 and 1 hr, but recovered after 3 hr in 500 ppm treatment group. The superoxide dismutase (SOD) and catalase (CAT) enzyme activities were observed to be increased. Heat-shock protein 70 (HSP70) was significantly increased compared to that of control group in all of the test groups. HSP70 mRNA groups was highly expressed in 500 ppm treatment.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.6
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• pp.1049-1053
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• 2009

This study was carried out to investigate the effects of Eucommia ulmoides Oliver (Du-Zhong) as a main ingredient in a mixture of various medicinal herbal extracts on blood pressure, serum lipid concentrations, and hematological variables in hypertensive patients. After 4 weeks on drinking the mixed medicinal herbal teas, systolic blood pressure remarkably decreased from 167.14 to 134.86 mmHg and diastolic blood pressure decreased from 100.00 to 87.10 mmHg. In terms of serum lipid profiles, there were no differences in total-cholesterol, HDL-cholesterol, LDL-cholesterol level, and atherogenic index, However, the level of triglycerol was significantly reduced from 237.1 before the experiment to 145.00 mg/dL after 4 weeks on drinking the mixed medicinal herbal teas. Serum triglyceride were remarkably reduced from 237.1 to 145.00 mg/dL in the hypertensive patients who had taken the combined medicinal herbal extracts. Compared with data obtained from the patients before the experiment, there were no differences in hematological variables (RBC, WBC, hematocrit, hemoglobin, platlets and homocysteine) after the 4 weeks experiments, but mean corpuscular hemoglobin concentration was significantly increased by 2.70% (p<0.05) in the blood samples. Based on these findings, it can be presumed that the examined mixed medicinal herbal tea may be effective in lowering blood pressure and in increasing mean corpuscular hemoglobin concentration due to reduced serum triglyceride levels in hypertension patients.

• Journal of Yeungnam Medical Science
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• v.8 no.1
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• pp.86-97
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• 1991

To obtain the basic data of prognosis of acute carbon monoxide(CO) intoxication, one hundred and sixteen cases of CO intoxication defined by carboxyhemoglobin(COHb) and admitted via emergency room of Yeungnam University Hospital from Oct. '85 to April' 89 have been clinically analyzed and evaluated, including delayed postanoxic encephalopathy(DPE) and the following results were obtained. 1. The ratio of male to female was 1:1.5 and mental state was drowsy mostly(26.2% of 116 cases) 2. The more disturbed the mental state, the more decreased was the arterial pH and $PaCO_2$, which may be the result of metabolic acidosis. 3. The early laboratory findings in patients of CO intoxication were as follows : leukocytosis-65.5%, increase of hematocrit-23.3%, hyperglycemia-19.8%, increase of GPT-19.8% increase of creatinine-0.9%, and glucosuria-12.1%. 4. The early findings of EKG were abnormal in 35.3% : change of rhythm-25.0%, abnormal ST segment-15.5% (change of rhythm and abonormal ST segment-5.2%) but the conduction disorder was not present. 5. The abnormal EEG above mild degree was 93.1%, of which moderate was most frequent(80.2%). 6. The incidence of DPE was 7.8% among all admitted CO patients. DPE cases had long duration of exposure time(8 hours), severe leukocytosis(20,000) and an abnormal EEG(MA).

• Journal of fish pathology
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• v.23 no.3
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• pp.293-302
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• 2010

Effects of formalin on removal of Pseudodactylogyrus spp. were examined against naturally infected eel, Anguilla japonica (weight 89.9~96g) at a water temperature of $28^{\circ}$. Prior to experiments for removal of the parasite, the hematological toxicity of formalin bath at 0~500 ppm for 30 min~24 h was assessed by hematocrit values (Ht). Based on the results of Ht, appropriate methods of treatment, concentrations and durations, were examined in the main study. There was no significant (P>0.05) change of Ht in 100 to 200 ppm for 24 h. In contrast, Ht increased significantly (P<0.05) at above 300 ppm. This suggests that physiological damage was caused by formalin bath treating with 300 to 500 ppm. Formalin bath with 100 and 200 ppm for 24 h caused significant decreases (P<0.05) in the infection of the parasite. In conclusion, the 100 ppm formalin for 24 hour-bath was found most recommendable for the effective treatment of Pseudodactylogyrus spp. for the gills of the infected eel because of the median lethal concentration ($LC_{50}$) of formalin to eel; cumulative mortalities were found to be 0 and 13.3%, respectively, following 24 h bathing.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.150-155
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• 2019

Cavitation refers to a phenomenon in which empty spaces occur in a fluid due to changes in pressure and a velocity. When a liquid moves at a high speed, the pressure drops below the vapor pressure, and vapor bubbles are generated in the liquid. This study used CFD to analyze the flow of fluid machinery used in marine and offshore plants. The goals are to ensure the validity of the analysis method for marine propellers in an open water test, to increase the forward ratio, and to use FLUENT to understand the flow pattern due to cavitation. A three-dimensional analysis was performed and compared with experimental data from MOERI. The efficiency was highest at advance ratios of 0.7 - 0.8. Thrust was generated due to the difference between the pressure surface and the suction surface, and it was estimated that bubbles would be generated in the vicinity of the back side surface rather than the face side of the propeller, resulting in more cavitation. The cavitation decreased sharply as the advance ratio increased. The thrust and torque coefficients were comparable to those of the MOERI experimental data except at the advance ratio of 1, which showed a difference of less than 5%. Therefore, it was confirmed that CFD can evaluate an open water propeller test.