• International Journal of Advanced Culture Technology
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• v.10 no.4
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• pp.286-293
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• 2022

In this study, we extracted sound waves that can improve psychological skills for volleyball players, investigated the changes that the application training of the extracted sound waves has on the brain waves of volleyball players, and the changes in brain waves are the psychological of volleyball players. The purpose of the research is to investigate the effect on technology. In order to achieve this purpose of the study, a total of 10 people from the experimental group and 10 from the control group were selected as the research subjects of university volleyball players with more than 5 years of volleyball experience. The experimental procedure was for the experimental group to listen to sound waves for more than 30 minutes at least 4 times a week for 12 weeks, and brain waves were measured 3 times before, during, and after. In addition, psychological skills were measured twice before and after. The measured data were subjected to t-test and two-way variance repeated measures analysis using SPSS 20.0. The results obtained through this process are as follows. First, as a result of analyzing the differences in psychological skills according to sound wave application training, there were statistically significant differences in goal setting and attention factors of the experimental group. Second, as a result of repeated measurement variance analysis at each time point according to the application of the sound wave application training program, it was found that alpha waves had a synergistic effect at the statistical significance level in the experimental group. Third, as a result of repeated measurement variance analysis at each time point according to the application of the sound wave application training program, it was found that the beta wave had a synergistic effect at the statistical significance level in the experimental group.

• 한국연소학회:학술대회논문집
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• 2004.11a
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• pp.97-106
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• 2004

Stability of laminar premixed planar flames inclined in gravitational field which generate vorticity is asymptotically examined. The flame structure is resolved by a large activation energy asymptotics and a long wave approximation. The coupling between hydrodynamics and diffusion processes is included and near-unity Lewis number is assumed. The results show that as the flame is more inclined from the horizontal plane it becomes more unstable due to not only the decrease of stabilizing effect of gravity but also the increase of destabilizing effect of rotational flow. The obtained dispersion relation involves the Prandtl number and shows the destabilizing effect of viscosity. The analysis predicts that the phase velocity of unstable flame wave depends on not only the flame angle but also the Lewis number. For relatively short wave disturbances, still much larger than flame thickness, the most unstable wavelength is nearly independent on the flame angle and the flame can be stabilized by gravity and diffusion mechanism.

• Journal of KSNVE
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• v.4 no.3
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• pp.295-305
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• 1994

The reflection coefficient of a material at oblique incidence is measured in a free field. The sound pressure distributions are measured at discrete points on two measurement lines and then decomposed into plane wave components by using spatial Fourier transform. The inciedent and reflected plane wave components are obtained from a set of "decomposition equations" of which uses the plane wave propagation theory. Numerical simulations and experiments have been performed to see the effect of finite size of measurement area. To reduce this effect, a window fuction has been performed to see the effects of finite size of mesurement area. To reduce this effect, a window function has been proposed and its effect on the measurement of sound absorbing material property has been studied as well. The reflection coefficient obtained by this method is compared with those obtained from other methods; 2-microphone method in a duct and an expirical equation of which determines the characteristic impedance .rho.c and propagation constant k of a material from flow resistance information.formation.

• Journal of the Korean Society of Combustion
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• v.9 no.4
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• pp.9-21
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• 2004

Stability of laminar premixed planar flames inclined in the gravitational field is asymptotically examined. The flame structure is resolved by a large activation energy asymptotics and a long wave approximation. The coupling between hydrodynamics and diffusion processes is included and near-unity Lewis number is assumed. The results show that as the flame is more inclined from the horizontal plane it becomes more unstable due to not only the decrease of stabilizing effect of gravity but also the increase of destabilizing effect of rotational flow. The obtained dispersion relation involves the Prandtl number and shows the destabilizing effect of viscosity. The analysis predicts that the phase velocity of unstable flame wave depends on not only the flame angle but also the Lewis number. For relatively short wave disturbances, still much larger than flame thickness, the most unstable wavelength is nearly independent on the flame angle and the flame can be stabilized by gravity and diffusion mechanism.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1028-1034
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• 2011

This paper have been studied that ocean wave power vibration generation system with two D.O.F.(degree of freedom) consists of buoy and vibration generation system with two D.O.F. for using efficiency of ocean wave energy. It selected main frequencies ${\omega}_1$, ${\omega}_2$ in frequency with ocean wave and it fitted them to the natural frequencies of vibration system with two D.O.F. in the vibrational power generation system. Then each the relative velocity of between the winding coil and the permanent magnet is faster than the velocity of ocean wave up and down motion by resonance phenomenon. Also the ocean wave power generation with two D.O.F. obtained the more electric energy then the ocean wave power generation with one D.O.F. by coupling effect for two D.O.F. vibration system. Therefore ocean wave power vibration generation system with two degree of freedom that is proposed in this paper has merits which not only using more energy in the ocean wave but also obtaining more electronic energy.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.101-105
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• 2000

This study was to investigate the effect of EEG wave type on visual cortex of visual target according to position of fixation point on the Korean. Visual evoked potential system used the BIO-Pag and recorded to 586 computer. The illumination was 500 lux and the visual target was red light dot of 3 cm size. The results of the convergence and divergence as follows: The visual stimulation waves on the visual cortex have about 70% of delta wave, about 10% of beta wave, about 9% of theta wave and about 7% of alpha wave respectively. The convergence state was much more appeared the fast wave on the comparative of the divergence. Therefore, the convergence state was much more producted the beta and alpha wave on the comparative of the divergence. On the other hand, on the convergence and divergence, the histogram amplitude of EEG wave appeared almost the non-Gaussian shape. According to the phase analysis of amplitude of EEG wave almost all type was linear shape.

• Journal of Hydrogen and New Energy
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• v.22 no.4
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• pp.552-558
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• 2011

A 50 kW class rotating body type wave energy converter consisted of two floating bodies and a PTO (Power Takeoff) unit is studied. As an wave energy extractor, the body is designed to have a VLCO (Variable Liquid-Column Oscillator) having a liquid filled U-tube with air chambers. Owing to the oscillation of the liquid in the U-tube caused by the air spring effect of the air chambers, the amplitude of response of the VLCO becomes significantly amplified for a target wave period. The PTO converts the rotational moment introduced from the relative motion of the hinged bodies to an hydraulic power by means of a cylinder. A high pressure accumulator, hydraulic motor and a generator are equipped in the PTO to convert the hydraulic power to electric power. A control law for adjusting the oscillation period of the VLCO is proposed for the efficient operation of the VLCO with various wave conditions. It is found that the effect of the air spring has an important role to play in making the oscillation of the VLCO match with the ocean wave. In this way, the wave energy converter equipped with the VLCO provides the most effective mode for extracting energy from the ocean wave.

• Journal of Ocean Engineering and Technology
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• v.30 no.6
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• pp.498-504
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• 2016

In this study, to predict the effect of beach nourishment at Haeundae Beach, the waves and wave-induced currents were compared before and after beach nourishment using the XBEACH model. Representative wave conditions were determined for the data observed during 2014 (KHOA). Then, the Hs,max and Hs,1/10 values, and their prevalent directions, were used in the numerical modeling input data. A variable grid system was used for the $5km{\times}2.5km$ model areas, and irregular waves based on the JONSWAP spectrum were given as incident wave conditions. In the summer season, eastward wave-induced currents were developed along the beach by the incident wave direction. Before the beach nourishment, the maximum speed around the surf zone was 1.2-1.5 m/s in the central zone of the beach, whereas the maximum speed increased to 1.4-1.6 m/s at the same areas when the currents toward Mipo Harbor were blocked as an effect of the groins after the beach nourishment. In the winter season, westward wave-induced currents were developed along the beach by the incident wave direction. After the beach nourishment, the maximum current speed increased slightly around the surf zone in the central area of the beach, and the littoral current speed decreased at the submerged breakwaters located at Dongbaek Island. As a result, after the beach nourishment, the maximum wave-induced currents increased about 10% in the surf zone of the central area of the beach.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1800-1805
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• 2008

Shiro-abhyanga is one of treatments of Ayurveda, which is the ancient system of health care and medicine in India. In this essay, I examined the effect of Shiro-abhyanga for relaxing stress of women in twentieth by the means of the brain wave test. The brain wave test showed that Shiro-abhyanga reduced Delta and Theta waves of the left brain but increased $\alpha$, SMR, Low-$\beta$ waves of the right brain. Delta and Theta waves are usually found in sleeping time. Their high measurement in awakening instructs the stress and depressing situations of objects. However the treatment of Shiro-abhyanga made the decrease of Delta and Theta waves and the increase of Alpha wave in working time. Alpha wave appears while objects are comfortable and peaceful from the relaxation of body and mind. Therefore the growth of Alpha wave says that the treatment of Shiro-abhyanga has an effect on mitigation of stress.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.3
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• pp.533-540
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• 2019

This study investigated the effect of extracorporeal shock wave therapy on nerve regeneration in nerve injured rats. In this study, we used 30 male Sprague-Dawley rats weighing 230-280g and 6 weeks old. Study groups were divided into two groups using a random sampling method: experimental group (n=15) treated with extracorporeal shock wave after sciatic nerve injury and control group (n=15) treated without extracorporeal shock wave after sciatic nerve injury. In this study, extracorporeal shock wave therapy equipment (OPTIMUS, SALUS TALENT 3, Korea) was used to apply extracorporeal shock wave therapy and applied to the sciatic nerve crush area of the right hind limb using low intensity. We measured the stance time and stride distance of the affected side using dartfish software. There was a statistically significant difference in the change of stance time and stride distance of the affected side between the experimental group using extracorporeal shock wave therapy and the control group without extracorporeal shock wave treatment. In conclusion, extracorporeal shock wave therapy has a positive effect on nerve regeneration.