• Journal of Society of Preventive Korean Medicine
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• v.16 no.3
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• pp.15-26
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• 2012

Objective : Only a few studies have investigated the life expectance and health related quality of life (HRQOL) about stroke patients. The purpose of this study is to analyze the life expectancy, preference based quality of life(QOL) and quality adjusted life years(QALYs) of stroke patients. Methods : We used data of 10,533 adults from 4th Korean national health and nutritional examination survey 2009 for evaluating HRQOL of stroke patients. We also analyzed the life expectancy for stroke patients using life table from national public health data. Finally we calculated the QALYs with and without stroke conditions and assumed the difference of QALYs. Results : The mean age of stroke patients was assumed to be 65. Lower income and less educated groups were prone to be exposed to the stroke conditions. Common comorbidities of stroke patients were ischemic heart attack, hypertension, diabetes and hyperlipidemia. The proportions of participants who reported problems in each of the five EQ-5D dimensions increased significantly at chronic stroke group. Participants with chronic stroke conditions had an almost 6-fold higher risk of impaired health utility(the lowest quartile of EQ-5D utility score) compared with non stroke participants, after adjustment of age, gender, income, education, comorbidity variables. The differences of life expectancy and QALYs between non-stroke and stroke group from the age of 65 till death were assumed to be 0.767 year and 3.103 QALYs. Conclusions : Although the authors analyzed the affecting factors of QOL and assumed the differences of life expectance and QALYs about stroke patients using domestic national data and statistic references, well designed cohort studies should be needed to prove the causal effects of affecting factors and to assume more correct QALY differences.

• Journal of the Korean Wood Science and Technology
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• v.35 no.5
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• pp.7-15
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• 2007

To evaluate the durability of finger-jointed woods according to change of humidity conditions, four types of finger-jointed woods glued with different kinds of adhesives and finger pitches were made with Sitka spruce, and the effect of humidity conditions on creep performances was investigated. The shape of creep curves differed among humidity conditions, and the inclination of creep curves was greatest in 85%RH, and lowest in 65%RH. Their creep curves showed a linear behavior beyond approximately one hour, regardless of humidity conditions. The A values of the creep curves fitted to power law increased with increasing relative humidity, whereas the A' values were in order of 30 > 85 > 65%RH unlike the A values. The initial deformation increased with increasing relative humidity, whereas the creep deformation unlike the initial deformation was in order of 85 > 30 > 65%RH, and it was found that the creep deformation of finger-jointed woods indicated the smaller amount in air-dry moisture content rather than in a low moisture content less than 30%RH. Finger-jointed woods with 6.8 mm (L) pitch had the greater creep amount than in those with 4.4 mm (S) pitch in all humidity conditions. The difference of creep amount between both adhesives in all humidity conditions was small. Relative creep at 240 hr was greatest as 62.2~71.9% in 85%RH, and the values indicated 2.1~2.6 times that of 30%RH and 3.0~3.6 times that of 65%RH and were equal or slightly greater than that of solid spruce.

• Korean Journal of Food Science and Technology
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• v.41 no.4
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• pp.435-440
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• 2009

Acetylcholinesterase (AChE) inhibitors, which enhance cholinergic transmission by reducing the enzymatic degradation of acetylcholine, are the only source of the compound that is currently approved for the treatment of Alzheimer's disease (AD). In these experiments, the concentration samples of green tea extracts were 100, 500, and 1,000 ${\mu}g$/mL. Among them, the highest concentration (1,000 ${\mu}g$/mL) of fresh green tea extracts showed the most potent inhibitory effect on AChE by reducing more than 40% of enzyme activity, and in a concentration-dependent pattern. In addition, we examined the effect of other storing conditions on AChE inhibition. In order to maintain storage for 3 months, the materials were held at the certain storing conditions of temperature (room temperature, 4 and $-20^{\circ}C$) and for water activity (0.81, 0.69, and 0.23). In these storing conditions, the difference in temperature did not contribute to the AChE inhibitory effect. Our presented data showed that the AChE inhibitory effect was affected by the concentration of green tea extract and by water activity (0.81). These results suggest that green tea may serve as a potential dietary source of AChE inhibitor.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.3
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• pp.219-224
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• 2001

This study was conducted to investigate the optimal conditions for the growth of soybean sprouts by ozone water watering. Optimal conditions for ozone water watering of soybean sprouts during cultivation at 2$0^{\circ}C$ were evaluated with ozone concentration(0.1~O.5 ppm) and watering frequency(1~9 times) by response surface methodology. The optimal conditions for growth of soybean sprouts were ozone concentrations of 0.20~0.32 ppm, ozone treatment frequency of 3.0~4.4 times. Germination rates, hypocotyl weights and hypocotyl lengths in the soybean sprouts cultivated under the optimal conditions increased by 13.3, 10.1 and 11.9%, respectively, whereas root weights decreased by 89.0%.

• Journal of the East Asian Society of Dietary Life
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• v.8 no.1
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• pp.57-65
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• 1998

To utilize deteriorated sweet persimmon effectively, response surface methodology(RSM) was used to determine the optimal vinegar fermentation conditions and monitored by a divided two stage fermentation. The optimum conditions for maximum alcohol content were obtained when the first stage (alcohol fermentation) was carried out with an initial sugar concentration of 18.5$^{\circ}$Brix, agitation rate of 140.8 rpm, fermentation time of 127.6 hr. When sugar concentration was 14$^{\circ}$Brix maximum alcohol content(7.1%) was predicted at fermentation conditions of 160 rpm in agitation rate, 140hr in fermentation time. The optimum conditions for maximum acidity were obtaiend when second stage(vinegar fermentation)was carried out 249.5 rpm in agitation rate, 148.8 hr in fermentation time. Predicted values at the optimum conditions were similar to experimental values.

• Wind and Structures
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• v.32 no.5
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• pp.501-508
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• 2021

The turbine industry demands a reliable design with affordable cost. As technological advances begin to support turbines of huge sizes, and the increasing importance of wind turbines from day to day make design safety conditions more important. Wind turbines are exposed to environmental conditions that can affect their installation, durability, and operation. International Electrotechnical Commission (IEC) 61400-1 design load cases consist of analyses involving wind turbine operating conditions. This design load cases (DLC) is important for determining fatigue loads (i.e., forces and moments) that occur as a result of expected conditions throughout the life of the machine. With the help of FAST (Fatigue, Aerodynamics, Structures, and Turbulence), an open source software, the NREL 5MW land base wind turbine model was used. IEC 61400-1 wind turbine design standard procedures assessed turbine behavior and fatigue damage to the tower base of dynamic loads in different design conditions. Real characteristic wind speed distribution and multi-directional effect specific to the site were taken into consideration. The effect of these conditions on the economic service life of the turbine has been studied.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.413-414
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• 2002

An automotive wheel bearing is one of the most important components to guarantee the service life of a passenger car. The endurance life of a bearing is affected by many parameters such as material properties, heat treatment, lubrication conditions temperature loading conditions, bearing geometry, internal clearance and so on. In this paper, we calculate the endurance life of wheel bearing units and analyze the sensitivity of bearing geometric parameters on the life by using Taguchi method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.670-673
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• 2002

Automotive wheel bearings are one of the most important components to guarantee the service life of a passenger car. The endurance life of a bearing is affected by many parameters such as material properties, heat treatment, lubrication conditions, temperature, loading conditions, bearing geometry, internal clearance and so on. In this paper, we analyze the relation between loads and deformations of wheel bearing units. On the basis of it we calculate the endurance life of wheel bearing units and analyze the contribution of bearing geometric parameters on the endurance life by using Taguchi method.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.5
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• pp.160-164
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• 2007

An automotive wheel bearing is one of the most important components to guarantee the service life of a passenger car. The endurance life of a bearing is affected by many parameters such as material properties, heat treatment, lubrication conditions, temperature, loading conditions, bearing geometry, internal clearance and so on. Generally, a tapered roller bearing gives longer endurance life than that of an equivalent size ball bearing. Consequently, the application of taper bearing units will be increased for more compact design and extended warranty. In this paper, we derive the relation between loads and deformations of a taper bearing unit. On the basis of that, we calculate the endurance life of the taper bearing unit considering initial axial clearance.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.5
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• pp.762-772
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• 2004

Fatigue life of a Piston for large liquid Petroleum liquid injection(LPLi) bus engines is analyzed considering effects of cooling condition parameters : temperature of cooling water, and heat transfer coefficients at oil gallery and bottom surface of piston head. Temperature of the piston is analyzed with varying cooling conditions Stresses of the piston from two load cases of pressure loading. and pressure and thermal loading are analyzed Fatigue life under repeated peak pressure and thermal cycle is analyzed by the strain-life theory. For the two load cases, required loading cycles for engine life are defined, and loading cycles to failure and partial damages are calculated. Based on the resulting accumulated fatigue usage factors, endurance of the piston is evaluated and effects of varying cooling condition Parameters are discussed.