• Journal of the Korean Society of School Health
• /
• v.4 no.1
• /
• pp.116-125
• /
• 1991

The purposes of this study are to identify the degree of exercise intent and behavior and to determine factors influencing exercise and behavior in middle school students. The subjects for this study were 658 middle school students in Chonbuk area. The data were obtained by questionaire for the period from Nov. 1 to Dec. 20, 1990. The instrument used for the study were included 6 existing scales and 2 scales developed by the researcher for this study. They are: 1) The exercise intent scale to assess the exercise plan even when they had no longer physical education. 2) The current exercise behavior to measure of exercise frequency for 1 week. 3) The scale to measure the level of self -esteem. 4) The scale to measure the level of knowledge about exercise. 5) The scale to measure the level of the perceived ability to make commitment. 6) The scale to measure the level of the perceived benifit of exercise. 7) The scale to measure the level of the perceived athletic ability. 8) The scale to measure the level of the attitude toward physical education. The data were analyzed using frequency, percentage, one way ANOVA, Pearson Coeffecients Correlation and stepwise multiple regression. The following; results were obtained. 1. Exercise intent level was in the intermediate range(mean on five point scale of 3.66, with 1 = definitely no). 2. The current exercise behavior level was relatively low(mean=1.77, with l=less than once per week and 4 = 4 or more times per week). 3. Self -esteem levels were in the intermediate range(mean on five point scale of 2.96, a mean of 5.0 indicate highest level of self-esteem.) 4. The levels of perceived ability to make commitments were in the intermediate range(mean=3.05, with 5.0 as most able). 5. The levels of perceived exercise as benificial were relatively high(mean=3.72, with 5.0 as most benificial). 6. Knowledge levels about exercise were realatively high(mean=3.97, with 5.0 as most knowledgeable). 7. The levels of perceived athletic ability were in intermediate range(mean=3.01, with 5.0 as highest score). 8. The levels of attitudes toward physical education were in the intermediate range(mean=3.29, with 5.0 as most favorable). 9. Among the general characteristic variables, sex, interest sports activities were related to the difference of exercise intent levels. 10. Of the predictor variables analyzed, self - esteem, perceived benifit of exercise, perceived athletic ability, knowledge about exercise and attitude about physical education correlated significantly and positively with exercise intent. Correlations of predictors with current exercise behavior were similiar to exercise intent, exept knowledge about exercise. 11. The stepwise multiple regression analysis shows findings as follows: 1) The most important factor to explain the difference of exercise intent was current exercise behavior. 2) The most improtant factor to explain the difference of current exercise behavior was perceived athletic ability.

• Journal of Ocean Engineering and Technology
• /
• v.31 no.1
• /
• pp.36-46
• /
• 2017

Most of the studies on the hydraulic characteristics of wave-current interaction have used 2-D hydraulic experiments or 2-D numerical simulations. However, it is difficult to understand the wave-current interaction found in actual estuaries using these. Therefore, a numerical water tank was constructed in this study to perform simulations involving a 3-D river mouth. The result showed a change in the water surface at the river mouth from the wave-current interaction. With an increase in the ratio ($V_c/C_i$) between the river current and wave celerity, the wave height and mean water level of the river increased at the wave and current meeting point. A higher $V_c/C_i$ caused a stronger wave-current interaction and increased the turbulence kinetic energy. Thus, the wave height attenuation became larger by the wave-current interaction with a higher $V_c/C_i$. In addition, it was possible to understand the flow characteristics in the vicinity of the river mouth as a result of the wave-current interaction using the mean flow and mean time-averaged velocity at the mid-cross section of river.

• Proceedings of the KSRS Conference
• /
• v.1
• /
• pp.352-355
• /
• 2006

In this study, the seasonal and inter-annual variation of sea surface current in the Gulf of Thailand were revealed through the use of WOD temperature and salinity data and monthly sea surface dynamic heights (SSDH) from TOPEX/Poseidon and ERS-2 altimetry data during 1995-2001. The mean dynamic height and mean geostrohic current were derived from the climatological data while SSDH data gave monthly dynamic heights and their geopstrophic currents. The mean geostrophic current showed strong southward and westward flow of South China Sea water along the gulf entrance. Counterclockwise eddy in the inner gulf and the western side of the gulf entrance associated with upwelling in the area. Seasonal geostrophic currents show basin-wide counterclockwise circulation during the southwest monsoon season and clockwise circulation during the northeast monsoon season. Upwelling was enhanced during the southwest monsoon season. The circulation patterns varied seasonally and inter-annually probably due to the variation in wind regime. And finally we found that congregation, spawning, and migration routes of short-bodied mackerel conform well with coastal upwelling and surface circulation in the gulf.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.30 no.6
• /
• pp.1021-1032
• /
• 1997

Satellite-tracked drifters deployed in the East Sea since 1991 are used to study the Tsushima Current (TC). It is found that the TC is a steady current with a mean speed of 10 cm/s before it enters the East Sea. Only during the summer, the TC flows along Honshu Island with a mean speed of $30\~40\;cm/s$ and then exits through the Tsugaru Strait. In fall and winter, the TC does not follow the coast along Honshu Island but it enters into the interior of the East Sea before it reaches the Tsugaru Strait. The water that passes the West Channel of the Korea Strait mostly comes from the western East China Sea and spreads into the interior of the East Sea. It also forms the large eddies in the southern East Sea. The outflow through the Tsugaru Strait comes from the interior of the East Sea in all seasons except summer. The mean speed of the Tsugaru Strait outflow is about 60 cm/s. The largest current variability is found in the eastern central area of the East Sea, south of sub-polar front.

• Korean Journal of Remote Sensing
• /
• v.18 no.5
• /
• pp.243-253
• /
• 2002

Time-mean and absolute geostrophic velocities of the Kuroshio current south of Japan are derived from TOPEX/Poseidon altimeter data using a Gaussian jet model. When compared with simultaneous measurements from a shipboard acoustic Doppler current profiler (ADCP) at two intersection points, the altimetric and ADCP absolute velocities correlate well with the correlation coefficient of 0.55 to 0.74. The accuracy of time-mean velocity ranges from 1 cm s$^{-1}$ to 5 cm s$^{-1}$. The errors in the absolute and the mean velocities are similar to those reported previously for other currents. The comparable performance suggests the Gaussian jet model is a promising methodology for determining absolute geostrophic velocities, noting that in this region the Kuroshio does not meander sufficiently and thus provides unfavorable environment for the performance of the Gaussian jet model.

• Journal of the Korean institute of surface engineering
• /
• v.26 no.5
• /
• pp.245-254
• /
• 1993

The effects of pulse current electrolysis conditions on the composition and the microstructure of Ag-Sn alloy were studied by using a pyrophosphate bath. Both cathode current efficiency and throwing power of alloy deposits formed under pulse plating conditions, decreased with increasing mean current density, and lower than those under D.C. electrolysis condition. Tin content of Ag-Sn alloy decreased noticebly with in-creasing the mean current density, while it increased with the increase of On-time from 1 to 10 ms. The pre-ferred orientation of Ag-Sn alloy changed with increasing cathode overpotential in the sequence of (100)longrightarrow(100)+(111)longrightarrow(111) at $20^{\circ}C$ and (110)longrightarrow(111)longrightarrow(111)+(100) at $30^{\circ}C$. The effective crystal grain size of the alloy was decreased by decreasing temperature from $30^{\circ}C$ to $20^{\circ}C$ and the surface structure of them was related to the preferred orientation.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.08a
• /
• pp.310-311
• /
• 2011

Dual-frequency (DF) capacitively coupled plasmas (CCP) are used to separately control the mean ion energy and flux at the electrodes [1]. This separate control in capacitively coupled radio frequency discharges is one of the most important issues for various applications of plasma processing. For instance, in the Plasma Enhanced Chemical Vapor Deposition processes such as used for solar cell manufacturing, this separate control is most relevant. It principally allows to increase the ion flux for high deposition rates, while the mean ion energy is kept constant at low values to prevent highly energetic ion bombardment of the substrate to avoid unwanted damage of the surface structure. DF CCP can be analyzed in a fashion similar to single-frequency (SF) driven with effective parameters [2]. It means that DF CCP can be converted into SF CCP with effective parameters such as effective frequency and effective current density. In this study, comparison of DF CCP and its converted effective SF CCP is carried out through particle-in-cell/Monte Carlo (PIC-MCC) simulations. The PIC-MCC simulation shows that DF CCP and its converted effective SF CCP have almost the same plasma characteristics. In DF CCP, the negative resistance arises from the competition of the effective current and the effective frequency [2]. As the high-frequency current increases, the square of the effective frequency increases more than the effective current does. As a result, the effective voltage decreases with the effective current and it leads to an increase of the ion flux and a decrease of the mean ion energy. Because of that, the negative resistance regime can be called the preferable regime for solar cell manufacturing. In this preferable regime, comparison of DF (13.56+100 or 200 MHz) CCP and SF (60 MHz) CCP with the same effective current density is carried out. At the lower effective current density (or at the lower plasma density), the mean ion energy of SF CCP is lower than that of DF CCP. At the higher effective current density (or at the higher plasma density), however, the mean ion energy is lower than that of SF CCP. In this case, using DF CCP is better than SF CCP for solar cell manufacturing processes.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.22 no.3
• /
• pp.181-190
• /
• 2010

In case of constructing submerged breakwaters, the circulation current is occurred around the open inlet because of mean water level difference between front and rear sides of them. The aim of this study is to investigate the flow control structure of new-type submerged breakwater which is able to reduce mean water level at rear side of it. At first, the numerical model (LES-WASS-3D) is validated by comparing with existing experimental data. And then, numerical simulation is carried out to examine wave height, mean water level and mean flow around the newtype submerged breakwater. From the numerical results, it can be pointed out that the new-type submerged breakwater with drainage system reduces the rip current around the open inlet.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.24 no.2
• /
• pp.159-165
• /
• 2006

This paper deals with the estimation of geostrophic current using the sea surface topography calculated from the geoidal height from EGM96 geopotential model and the mean sea surface height from CLS_SHOM mean sea surface model. The CLS_SHOM model was developed using the altimetry data set. The estimation of geostrophic current is available in the characteristic research of ocean in many country, while for East Sea a few studies were done. The goal of this study is basically to provide the characteristics of geostrophic current in East Sea. The results show that the mean sea surface topography (SST) in East Sea is about 0.37 m and the mean geostrophic velocity is -0.028 m/sec. The Pacific water enters into the East Sea through the Korea Strait and after passing the strait, this inflow splits into two branches: one flows northward along the Korean coast and another outflows into Pacific ocean through Tsugaru and Soya strait passing the east-northeastward along the Japanese outer shelf, and outflows into Okhotsk ocean.

• Journal of the Korean Society for Railway
• /
• v.10 no.4
• /
• pp.414-419
• /
• 2007

The contact characteristics of the current collection system are investigated by analyzing data collected during a test run of the Korean high speed rail vehicle. For the analysis, the signals from accelerometers and load cells attached to the various parts of the pantograph are analyzed in both the time and frequency domains. In the frequency domain, the pantograph response consists of low frequency components related to the rigid-body motion of the panhead assembly and high frequency components due to the structural vibration modes of the pantograph. The analysis shows that the inclusion of the high frequency structural vibration modes of the pantograph in the contact force calculation has a negligible effect on the predicted mean value of the contact force but significantly affects the magnitude of its fluctuations. This finding implies that numerical simulations using lumped element models of the pantograph may accurately predict the mean contact force but is limited in its capacity for predicting the fluctuation about the mean. Since the ratio of the fluctuation to the mean in the contact force increases with increased train speed, the limitation of the predictions based on numerical simulation results becomes more pronounced at higher train speed.