• Journal of the Korean Physical Society
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• v.73 no.11
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• pp.1650-1656
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• 2018

Photons generated via spontaneous parametric down-conversion (SPDC) have broad spectrums and suffer from dispersive broadening of the temporal wave packets when they are transmitted through dispersive media. In this paper we theoretically and experimentally study the detailed amount of the temporal broadening of the two-photon wave packets generated via both type-I and type-II SPDC with ${\beta}-BaB_2O_4$ of various lengths, by transmitting them through optical fibers. We interpret the results with respect to the spectral properties of the two-photon wave packets. We believe that our results will contribute to implementing protocols involving long-range distributions of photon pairs.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.6
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• pp.757-762
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• 2015

This paper examine how CCT affected to writing task performance and EEG through 24 elementary students from in July to September, 2014. The study analyzed EEG that was changed in a task performance under an orange color light and a white color light in a laboratory for stabilization and relaxation. The study results showed that an alpha wave, beta wave, high-beta wave were high under the white color light. The task performance time, however, showed significant fast performance under the orange color light. Although pre-existing low CCT has been considered as typical type for stabilization and relaxation, this study provides that the various applications in the elements of cognition, tasks, and types can affect improvement of task performance and occupation ability.

• International Journal of Ocean System Engineering
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• v.4 no.1
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• pp.19-28
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• 2014

The tension leg platform (TLP) is a vertically moored structure with excess buoyancy. The TLP is regarded as moored structure in horizontal plan, while inherit stiffness of fixed platform in vertical plane. In this paper, a numerical study using modified Morison equation was carried out in the time domain to investigate the influence of nonlinearities due to hydrodynamic forces and the coupling effect between surge, sway, heave, roll, pitch and yaw degrees of freedom on the dynamic behavior of TLP's. The stiffness of the TLP was derived from a combination of hydrostatic restoring forces and restoring forces due to cables and the nonlinear equations of motion were solved utilizing Newmark's beta integration scheme. The effect of tethers length and wave characteristics such as wave period and wave height on the response of TLP's was evaluated. Only uni-directional waves in the surge direction was considered in the analysis. It was found that for short wave periods (i.e. 10 sec.), the surge response consisted of small amplitude oscillations about a displaced position that is significantly dependent on tether length, wave height; whereas for longer wave periods, the surge response showed high amplitude oscillations about that is significantly dependent on tether length.

• Physical Therapy Korea
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• v.6 no.3
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• pp.59-71
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• 1999

The purpose of this study was to determine the effect of varying levels of photobiostimulation treatment dosage on plasma ${\beta}$-endorphin concentration in humans. The subjects of this study were 21 healthy men and women, who were students of the Department of Physical Therapy, College of Health Science, Seonam University. This study was performed from October 26, 1998 to November 5, 1998. All subjects were assigned to one of three groups: a 2.0 $J/cm^2$ laser group, a 4.0 $J/cm^2$ laser group, an 6.0 $J/cm^2$ laser group. He-Ne laser (632.8 nm wave length) and infrared laser (820 nm wave length) of three different energy densities (2.0, 4.0, and 6.0 $J/cm^2$) were applied on the Su-Sam-Ri (L I 10) and Hab-Gog (L I 4) of acupuncture points. Blood samples were taken at pre-treatment, 30 min's post-treatment and 60 min's post-treatment. The level of ${\beta}$ endorphin was measured by radio immuno assay. The data were analyzed by descriptive statistics and repeated measure two-way ANOVA. The results of this study were as follows: 1) The human plasma ${\beta}$-endorphin concentrations were noted to significantly increase due to the energy densities of laser photobiostimulation (p<0.05). 2) The human plasma ${\beta}$-endorphin concentrations were noted to significantly increase during the period after laser photobiostimulation (p<0.05).

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.5
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• pp.23-29
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• 2015

In this study, human is the subject of driving a car, the actual EEG is a biological information in a number of reactions that are displayed while driving the vehicle by using a measuring device, occurs during travel of the road EEG to be collected, number of experiments the collected material on the basis of changes associated with running time, extracts the factors such as changes due to road geometry, and analysis was performed. The required changes in the EEG occurring during traveling experiment analysis alpha (${\alpha}$) waves, beta (${\beta}$) wave, after the primary extraction in the form of gamma (${\gamma}$) faction, the brain wave frequency of the entire period of the experiment change rate extracts, to calculate the change in frequency in response to EEG characteristics by applying the regression model to observe a learning effect in response to an increase in the number of experiments, as a result, depending on the number of experiments, EEG changes due to individual differences. The show, by repeatedly driving a section like this, it was possible to verify that comfortably travels driver accustomed in accordance with the stored road geometry and signal, safety facilities.

• Journal of Oriental Neuropsychiatry
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• v.18 no.2
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• pp.89-100
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• 2007

Objective : The purpose of this study is to examine relationship between cognitive function and sasang constitution by analyzing EEG status of company workers in Cheon-An. Method : 59 company workers were tested with cognitive assessment EEG program and questionaire for the Sasang Constitution Classification II. They were assorted by Sasang Constitutions, and we analyzed its correlation with cognitive assessment score and EEG data. Results : 1. According to mean active EEG rhythm of Alpha. H-Beta, Gamma wave, there were no significant difference among Sasang Constitution. 2. According to mean success, error, concentration, response, workload and left/right brain activity score, there were no significant difference among Sasang Constitution. 3. According to mean active EEG rhythm of Theta, SMR, M-Beta wave, Soyangin(少陽人)'s value was significantly higher than that of Taeumin(太陰人) 4. According to mean cognitive strenghth score, Soyangin(少陽人)'s value was significantly higher than that of Taeumin(太陰人). Conclusion : In conclusion, Sasang Constitutional difference has no relevance with cognitive abilities However, Soyangin(少陽人) showed higher mean active EEG rhythm of Theta, SMR, M-Beta wave than that of Taeumin(太陰人). In addition, Soyangin(少陽人) also showed higher mean cognitive strenghth score than that of Taeumin(太陰人).

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.2
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• pp.193-197
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• 2013

In this study, ultrasonic nonlinear characteristics in the heat-treated aluminum alloy have been evaluated. The nonlinearity of ultrasonic wave has been measured as the acoustic nonlinear parameter ${\beta}$, depending upon the amplitude ratio of the second-order harmonic and the fundamental frequency component of ultrasonic wave propagating through the materials. The parameter ${\beta}$ measurement has been carried out with the reflected signals from the back-wall of specimens at the same plane using the contact-type transducers. The heat-treatment, aging, has been achieved at $300^{\circ}C$ for various durations in the range of 1 to 50 hours. The tensile strength and elongation are obtained by the tensile test and then compared with the parameter ${\beta}$. There is a peak of the acoustic nonlinear parameter ${\beta}$ on 5 hours aging and the ${\beta}$ decreases thereafter, exhibiting closed relations with tensile strength and elongation. Also, the heat-treatment time showing peak in the parameter ${\beta}$ was identical to that showing severe change in the ${\sigma}-{\varepsilon}$ curve. These results suggest that the acoustic nonlinear parameter ${\beta}$ can be used for monitoring the strength variations with aging of aluminum alloys.

• Journal of applied mathematics & informatics
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• v.42 no.1
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• pp.105-121
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• 2024

We consider incompressible, inviscid, stratified shear flows in β plane. First, we obtained an unbounded instability region intersect with semi-ellipse region. Second, we obtained a bounded instability regions depending on Coriolis, stratification parameters and basic velocity profile. Third, we obtained a criterion for wave stability. This has been illustrated with standard examples. Also, we obtained upper bound for growth rate.

• Ocean Systems Engineering
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• v.3 no.2
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• pp.149-165
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• 2013

Tension leg platforms (TLP's) are highly nonlinear due to large structural displacements and fluid motion-structure interaction. Therefore, the nonlinear dynamic response of TLP's under hydrodynamic wave loading is necessary to determine their deformations and dynamic characteristics. In this paper, a numerical study using modified Morison Equation was carried out in the time domain to investigate the influence of nonlinearities due to hydrodynamic forces and the coupling effect between all degrees of freedom on the dynamic behavior of a TLP. The stiffness of the TLP was derived from a combination of hydrostatic restoring forces and restoring forces due to cables and the nonlinear equations of motion were solved utilizing Newmark's beta integration scheme. The effect of wave characteristics was considered.

• Journal of Digital Convergence
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• v.12 no.1
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• pp.467-473
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• 2014

The purpose of this study is to monitor the physiological changes by measuring EEG, blood pressure, heart rate, etc after applying progressive relaxation technique to university archery players in order to verify the effect of progressive relaxation through respiration, and, ultimately, improve an athlete's archery performance. This study chose 13 female archery athletes. The EEG, blood pressure, and heart rate of the athletes were measured before applying Jacobson's progressive relaxation technique for 12 weeks, during which the EEG, blood pressure, and heart rate were measured 3 times a week after 15 to 20 minutes of training before every measurement. We used the SPSS18.0 program for technical analysis to check the general features of the athletes and carried out the paired t-test to examine the changes made to the EEG, blood pressure, and heart rate of a single test group before and after the experiment. All statistical level of significance was maintained at ${\alpha}=0.5$. The results are as follows. First, after 12 weeks of appliance, between the targets' relative ${\alpha}$ wave and ${\beta}$ wave, the relative ${\alpha}$ wave showed a statistically significant increase while the relative ${\beta}$ wave showed no changes. Second, after 12 weeks of appliance, in terms of blood pressure, the systolic pressure showed no changes while the diastolic pressure showed a statistically significant change. Third, there was no statistically significant change to the heart rate. In conclusion, progressive relaxation through breathing has a positive effect on the archery athletes.