• Journal of Korean Society for Atmospheric Environment
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• v.15 no.3
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• pp.257-266
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• 1999

In order to analyze the effect of meteorological elements on ozone concentration, we carried out cross-correlation of the elements with ozone concentraton, and time series analysis on them. As a result, it revealed that temperature, wind speed and humidity are not independent variables with ozone concentrations, and also, solar radiation and mixing height are the major elements that affect them. We developed models for ozone with solar radiation and mixing height as dependent variables to verify the effect of major meteorological elements. The predicted ozone concentration has strong correlation coefficients, So, We could conclude that we can predict ozone concentreation only with solar raidation and mixing height as dependents.

• Journal of Information Display
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• v.10 no.4
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• pp.143-148
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• 2009

The theoretical current density equations for organic semiconductors was derived according to the internal carrier emission equation based on the diffusion model at the Schottky barrier contact and the mobility equation based on the field dependence model, the so-called "Poole-Frenkel mobility model." The electric field becomes constant because of the absence of a space charge effect in the case of a higher injection barrier height and a lower sample thickness, but there is distribution in the electric field because of the space charge effect in the case of a lower injection barrier height and a higher sample thickness. The transition between the injection- and bulk-limited currents was presented according to the Schottky barrier height and the sample thickness change.

• Journal of the Korean Society of Safety
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• v.24 no.1
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• pp.37-42
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• 2009

The present study is to estimate the effect of wave height affecting at the front face of breakwater systems, when a submarine trench is dredged in the distant offshore from outer breakwater. The wave diffraction field, which is important hydraulic factor in the ocean, is considered to be two dimensional(2D) plane and the configuration of the submarine trench on the sea bed designated by single horizontal long-rectangular system. The numerical simulation is performed by using Green function based on the boundary integral equation and meshed at moving boundary conditions. The results of present numerical simulations are illustrated by applying the normal incidence. It is shown that the ratios of wave height reduction at the front face of breakwater systems are approximately 20% by the effect of placing long trench on the sea bed. This study can effectively be utilized for safety assessment to various breakwater systems in the ocean field.

• Earthquakes and Structures
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• v.24 no.3
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• pp.155-163
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• 2023

The purpose of this paper is to investigate the coupled effect of SSI and pounding on dynamic responses of unequal height adjacent buildings with insufficiently separation distance subjected to seismic loading. Numerical investigations were conducted to evaluate effect of the pounding coupling SSI on a Reinforced Concrete Frame Structure system constructed on different soil fields. Adjacent buildings with unequal height, including a 9-storey and a 3-storey reinforced concrete structure, were considered in numerical studies. Pounding force response, time-history and root-mean-square (RMS) of displacement and acceleration with different types of soil and separations were presented. The numerical results indicate that insufficient separation could lead to collisions and generate severe pounding force which could result in acceleration and displacement amplifications. SSI has significant influence of the seismic response of the structures, and higher pounding force were induced by floors with stiffer soil. SSI is reasonable neglected for a structure with a dense soil foundation, whereas SSI should be taken into consideration for dynamic analysis, especially for soft soil base.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.83-88
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• 2004

High voltage AC electric field has been applied to turbulent propane jets to investigate the effect of electric field on liftoff characteristics. Liftoff velocity and liftoff height have been measured by varying the applied voltage and frequency. Liftoff velocities were delayed and liftoff heights were reduced by applying AC, not by DC. The electric effect became disappeared with further increasing jet velocities, which shows that the effect can be explained by the balance between inertia force and electric force. The flame stabilization effect was intensified as either applied voltage or frequency increased. Plasma streamers were generated between the flame and the jet under high voltage conditions. Liftoff velocity in the absence of plasma can be well correlated by the function of voltage and frequency.

• Physical Therapy Korea
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• v.6 no.2
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• pp.43-55
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• 1999

In today's society, many women wear high-heeled shoes, but the effect of heel height on lumbar lordosis has not been clearly defined. The objective of this study was to identify the influence of heel height and general characteristics of subjects on lumbar lordosis. The subjects of this study were 40 healthy women who were students of the Department of Physical Therapy, College of Rehabilitation Science, Taegu University. Flexible ruler measurement was used to measure the lumbar lordosis at barefoot, 3 cm and 7 cm high-heeled standing positions. The results were as follows: 1) Significant statistical decrease in lumbar lordosis was observed as heel heights were increased from barefoot to 7 cm high heel. 2) There were no statistically significant differences between lumbar lordosis according to three different heel heights and weight, body mass index. 3) Lumbar lordosis measured at different heel heights was related to subject's height. With increasing subject's height, lumbar lordosis that measured from each heel height was significantly decreased. As heel heights were increased from barefoot to 7 cm high heel, significant statistical decrease in lumbar lordosis was observed in the subjects whose height were 151~160 cm. 4) Intrarater reliability on lumbar lordosis taken with a flexible ruler was good, with Cronbach ${\alpha}$ values of 0.8971 for barefoot, 0.8107 for 3 cm and 0.9002 for 7 cm high-heeled standing positions.

• Journal of Korean Physical Therapy Science
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• v.19 no.2
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• pp.1-7
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• 2012

Purpose : The purpose of this study was to investigate the effect of different heel height on the electromyographic (EMG) activity in Rectus abdominis (RA) and Erector spinae (ES) during gait activity. Methods : A repeated measures design was used. 33 healthy females carried out a standardized gait activity under 3 conditions; with heel wedges of 1, 7, and 12cm in height. EMG activity was recorded from RA and ES during the activity. Data was analysed using the repeated one-way ANOVA. Results : First, as the shoe-heel height was getting higher, change of muscle activation indicated the statistically significant difference in rectus abdominis(p<0.05). Second, as the shoe-heel height was getting higher, change of muscle activation indicated the statistically significant difference in erector spinae(p<0.05). Conclusion : We found that as heel height increased, there was an increase in EMG activity in both RA and ES. This indicated that no RA : ES imbalance was elicited. This study provides information that will inform future research on how heel height affects muscle activity around the trunk.

• Asian Journal of Turfgrass Science
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• v.13 no.3
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• pp.139-146
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• 1999

This studies was carried out to estimate the influence of mowing height, time lapse, rolling, and dew removal on green speed of putting green in Lake Side C. C. on 29, 30 Jun. 1998. The results were as follows. As mowing height increased, green speed tended to be decreased. After mowing, green speed tended to be decreased over the time, and appeared to be decrease significantly on the next day[Y=3.206-0.127.X1-1.41$\times$10-2.X4(Y=green speed, X1=mowing height, X4=time lapse)]. This suggests that the frequency of mowing must be increased to maintain the green speed. But, frequent mowing cause the turfgrass of putting green to be stressed. Rolling tended to increase green speed[Y=3.555-0.202.X1+0.111.X2(Y=green speed, X1=mowing height, X2=rolling)]. Thus, rollers is thought to be an tool used to increase green speed and rolling is expected to be able to decrease turfgrass stress while maintaining the performance level of the putting green. Dew removal appeared to increase green speed significantly[Y=2.499-0.125.X1+0.366.X3(Y=green speed, X1=mowing height, X3=dew removal)]. Thus, dew removal is expected to maintain the green speed in the morning.

• Journal of the Korea Safety Management & Science
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• v.19 no.1
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• pp.9-13
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• 2017

In this study, the height of the flame required to estimate the heat flow path and flame spread in pool fire has been applied by the empirical formula, but it is calculated without applying the pressure and temperature parameters of the fire room. Until now, the height of the flame applied to pool fire was $l_F=0.235Q^{2/5}-1.02D$ in the Heskestad empirical formula, but accurate temperature calculation was not possible due to the temperature and pressure which are not influenced by the flame height. Therefore, applying the temperature and pressure around it can calculate the exact flame height, which can be applied to fire investigation and fire dynamics. The structure of the flame is divided into a continuous flame, an intermittent flame, and a buoyancy flame, but it is assumed that the flame height is calculated from the visual aspect to the intermittent flame region, and the temperature of the buoyancy flame is very low. The effect of heat of vaporization on the height of flame was investigated. The results showed that flame height was different according to the pressure and temperature around the fire room.

• Journal of Wind Energy
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• v.14 no.4
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• pp.75-86
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• 2023

We observed five species and 163 individuals of birds in the Demonstration Offshore Wind Farm in the southern part of the West Sea in Korea, and 33 species and 4,023 individuals from Gusipo to Dongho Beach. The most dominant bird in both areas was the black-tailed gull, Larus crassirostris. The flight height of birds for collision risk (wind turbine and bird) was divided into two groups. First, the safe height was from sea level to 20 m (< 20 m), with no effect from the action of revolving blades. Second, the danger height was more than 20 m from sea level (> 20 m), with a collision risk from the action of revolving blades. Birds flying a safe height (< 20 m) were 83.9% (271 individuals) and danger height (> 20 m) were 16.1% (52 individuals). Also, 11.7% of birds (35 individuals) used the inside of the Demonstration Offshore Wind Farm as a habitat for foraging and resting, and 88.3% birds used the outside. We suggest that the risk of collision with the wind farm was low due to the relatively low flight height of birds and distance between wind turbines (> 800 m).