• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.69-78
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• 2002

This paper examines the effects on mental fatigue of changes in the intensity of physical activity. A treadmill-equipped instrument and perception tester were used to attain several levels of physical activity In this paper, In order to determine the individual levels of physical activity of subjects, Borg-RPE scale, Heart Rate(HR) and Respiratory Quotient(RQ) were used. Also, an addition test in whole-body activity on treadmill-equipped instrument as an indicator of mental fatigue were performed. In the above experiments, the scores obtained in addition test administered before and after physical activity at each intensity level used. Restricted within the limits of this paper, the results of these tests showed that mental fatigue decreased after physical activity.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.182-187
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• 2001

This paper examines the effects on human reaction time and mental fatigue of changes in the intensity of physical activity. A treadmill-equipped instrument and perception tester were used to attain several levels of physical activity. In this paper, in order to determine the individual levels of physical activity of subjects, Borg-RPE scale, Heart Rate(HR) and Respiratory Quotient(RQ) were used. Also, a reaction test in whole-body activity on treadmill-equipped instrument and an addition test as an indicator of mental fatigue were performed. In the above experiments, the scores obtained in addition test administered before and after Physical activity at each intensity level used. Restricted within the limits of this paper, the results of these tests showed that mental fatigue decreased after physical activity.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.180-183
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• 2003

In this work. a potential inexpensive epoxy resin. epoxidized soybean oil (ESO) was synthesized and applied as a toughening agent for 4.4'-tetradiglycidyl diaminodiphenyl methane (TGDDM). The chemical structure of ESO was characterized by FT-IR, $^1H NMR, and ^{13}C NMR$ spectroscopy. The curing behaviors. thermal stabilities. fracture toughness. and flexural strength of TGDDM/ESO blend systems were investigated by using the dynamic DSC. thermogravimetric analysis (TGA). and flexural tests. The thermal stabilities of TGDDM/ESO blend systems were decreased with increasing ESO contents. whereas the critical stress intensity factor ($K_{IC}$) and flexural strength ($\sigma_f$) were increased with ESO contents up to 10 wt% ESO.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.176-186
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• 1996

The phenomena of drag reduction using small quantities of a liner macromolecules has attracted the attention of many experimental investigations. On the other hand drag reduction in two phase flow can be applied to the transport of crude oil, phase change system such as chemical reactor, pool and boiling flow, and to flow with cavitation which occurs pump impellers. But the research on dragreduction in two phase flow is not sufficient. The purpose of the present work is to evaluate the drag reduction by measuring pressure drop, void fraction, mean liquid velocity and turbulent intensity whether polymer additives a horizontal single and two phase system or not. Flow pattern of air-water two phase flow was classified by electrical conductivity probe signal. Velocities and turbulent intensities of signal were measured simultaneously with a Hot-film anemometer.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.58.3-59
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• 2018

We investigate velocity oscillations in a solar quiet region by using the spectral data of the $H{\alpha}$ and Ca II $8542{\AA}$ lines. The data were acquired by the Fast Imaging Solar Spectrograph installed at the 1.6 m Goode Solar Telescope of Big Bear Solar Observatory. According to Chae & Litvinenko (2018)'s theoretical work, there is a correlation between dominant period of the oscillations and the temperature of the temperature minimum region in a non-isothermal atmosphere. In our study, we measure the temporal variations of the intensity and the line of sight Doppler velocity, and find out the relations between the intensity and dominant period of the oscillations. In addition, we investigate oscillations in a few distinct regions and discuss regional characteristics of the oscillations.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1617-1622
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• 2008

We report a new molecular detection process which measures the changes in the plasmon resonance peaks of periodic Au nanoparticle arrays fabricated using the electron beam lithography. As the Au nanoparticle arrays are modified by the chemical reaction in solutions having various concentrations of a target molecule, both the position and intensity of the plasmon peak change in proportion to the concentration of the target molecule. We expect that the process developed in this work can be employed for fine tuning of the plasmon peak wavelength and also for the optical detection of various kinds of molecules. Moreover, this method may improve the measurement accuracy compared with existing approaches that use only one change (peak wavelength or peak intensity) as a readout value for the molecular detection.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.577-582
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• 2004

The photocatalytic degradation of atrazine and PCP, a endocrine disruptors, has been investigated over $TiO_2$ photocatalysts under ultraviolet (UV) light irradiation. The effect of operational parameters, i.e., pH, light intensity and persulphate concentration on the degradation rate of aqueous solution of atrazine and PCP has been examined. The results presented in this work demonstrate that, as pH and the light intensity increased, the photocatalytic reaction rates were enhanced. Individual use of $TiO_2$-persulphate was far more effective than using only $TiO_2$ in atrazine and PCP removal. Based on the overall experimental results, the photocatalytic oxidation of atrazine and PCP with the coated $TiO_2$ photocatalyst is found to be very effective under the operational conditions delineated in this study.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.148-155
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• 2024

We are designed was to find an efficient warm-up method for resistance training for muscle hypertrophy, and 10 males with at least 3 years of resistance training experience were selected as subjects. The 75% 1RM was measured directly based on the pre-measured bench press 1RM. After that, the main experiment of 75% 1RM bench press according to the three warm-up methods was conducted one week apart, and all experiments were randomized and cross-over. Performance according to the warm-up method (3) was measured by total exercise volume, and physiological changes were determined by myocardial workload. All post-measurement data were analyzed using SPSS.22.0 and analyzed using repeated measures one-way ANOVA and contrast comparisons were made using the deviation method. The results showed that the method of gradually increasing the number of repetitions by performing the same intensity as the intensity of the main exercise in the form of muscle hypertrophy, but at submaximal repetitions, showed the highest performance.

• Bulletin of the Korean Mathematical Society
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• v.48 no.4
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• pp.737-757
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• 2011

This work is concerned with an optimal selling rule for a large position of stock in a market. Selling a large block of stock in a short period typically depresses the market, which would result in a poor filling price. In addition, the large selling intensity makes the regime more likely to be poor state in the market. In this paper, regime switching and depressing terms associated with selling intensity are considered on a set of geometric Brownian models to capture movements of underlying asset. We also consider the liquidation strategy to sell much smaller number of shares in a long period. The goal is to maximize the overall return under state constraints. The corresponding value function with the selling strategy is shown to be a unique viscosity solution to the associated HJB equations. Optimal liquidation rules are characterized by a finite difference method. A numerical example is given to illustrate the result.

• Journal of ILASS-Korea
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• v.23 no.4
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• pp.169-174
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• 2018

In this work, optimization of blade shape for the improvement of mixture formation and vortex of intake port was performed by numerically, and the combustion performance of CI engine with optimized blade shape was investigated. To achieve this, 3 types of blade shape were studied under the different air flow mass conditions and the numerical results were investigated in terms of humidification water, moisture concentration, and velocity distributions. Evaporated liquid mass was also compared under various test conditions to reveal the turbulent intensity in an intake port. It was observed that the optimized blade shape can improve the humidification water, moisture concentration, and velocity distributions of intake port inside. The evaporated liquid mass was also increased under the conditions with blade. Especially, low NOx emissions was observed with optimized blade condition.