• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.3-10
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• 2001

In order to establish the intensity-magnitude relation far the Korean earthquakes, those relations for the earthquakes in the Sino-Korean craton were estimated. In this process, earthquake data of northeastern China region whose geological environment is similar to Korea Peninsula were also utilized. These data were analyzed not only with linear fit, but also with non-linear fit. The fellowing relation, M=0.57 $\times$ 1$_{e}$ + 2.86, seems appropriate for the present, but its validity should be tested more in the future.e.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.415-418
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• 1996

Etching Process, one of the most important process in semiconductor fabrication, has input control part of which components are pressure, gas flow, RF power and etc., and plasma gas which is complex and not exactly understood is used to etch wafer in etching chamber. So this process has not real-time feedback controller based on input-output relation, then it uses EPD(End Point Detection) signal to determine when to start or when to stop etching. Various type EPD controller control etching process using EPD signal obtained from optical intensity of etching chamber. In development EPD controller we concentrate on compensation of this signal intensity and setting the relative signal magnitude at first of etching. We compensate signal intensity using neural network learning method and set the relative signal magnitude using fuzzy inference method. Potential of this method which improves EPD system capability is proved by experiences.

• IMMUNE NETWORK
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• v.16 no.2
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• pp.109-115
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• 2016

To find the relation between exercise and cytokines, we examined the effect of the training intensity on the levels of cytokines, including interferon-gamma (IFN-γ), interlukine-4 (IL-4) and interlukine-4/interferon-gamma ratio (IL-4/IFN-γ ratio) in female Futsal players. Twelve well-trained female college Futsal players aged 19~22 participated in this study. The athletes completed 30-min of running at 60~65% maximal heart rate [moderate-intensity exercise], and 30-min of running at 75~80% maximal heart rate [high-intensity exercise]. peripheral blood samples were collected 24 h before and 24 h and 48 h after each of the exercise bouts. finding showed that The 30-min bout of moderate-intensity exercise induced a significant increase in IFN-γ (p=0.01) and significant decreases in IL-4 (p=0.001) and IL-4/IFN-γ ratio (p=0.003). And also, 30-min of running at 75~80% maximal heart rate induced increase in IFN-γ (p=0.07) and decreased in IL-4 (p=0.01) and IL-4/IFN-γ ratio (p=0.06) that these changes not significantly. In summary, exercise intensity can effect on the magnitude of changes in cytokines. It seems that moderate intensity exercise enhances cytokine pattern in female college Futsal players.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.2
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• pp.49-56
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• 2010

In general, the seismic intensity deduced from instrumental data has been evaluated from the empirical relation between the intensity and the PGA. From the point of view that the degree of earthquake damage is more closely associated with the seismic intensity than with the observed PGA, JMA developed the instrumental seismic intensity (JMA instrumental intensity) meter that estimate the real-time seismic intensity from the observed strong motion data to obtain a more correct estimate of earthquake damage. The purpose of the present study is to propose a practical application of the JMA instrumental intensity in Korea. Since the occurrence of strong earthquakes is scarce in the Korean Peninsula, there is an insufficiency of strong motion data. As a result, strong motion data were synthesized by a stochastic procedure to satisfy the characteristics of a seismic source and crustal attenuation of the Peninsula. Six engineering ground motion parameters, including the JMA instrumental intensity, were determined from the synthesized strong motion data. The empirical relations between the ground motion parameters were then analyzed. Cluster analysis to classify the parameters into groups was also performed. The result showed that the JMA acceleration ($a_0$) could be classified into similar group with the spectrum intensity and the relatively distant group with the CAV (Cumulative Absolute Velocity). It is thought that the $a_0$ or JMA intensity can be used as an alternative criterion in the evaluation of seismic damage. On the other hand, attenuation relation equations for PGA and $a_0$ to be used in the prediction of seismic hazard were derived as functions of the moment magnitude and hypocentral distance.

• 한국해양학회지
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• v.12 no.1
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• pp.7-12
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• 1977

Vertical mixing in the ocean affects the formation of water masses as well as the vertical distribution of nutrients and dissolved substances. this study is to investigate the effect of stability on the intensity of vertical transfer in the case of shallow and straitfied channel. It is found that the relation of the stability and vertical turbulent diffusion is given by K$\sub$z/ = -${\beta}$-(c+${\beta}$) / ${\alpha}$(E-1/${\alpha}$) where K$\sub$z/ and E denotes the vertical turbulent diffusion coefficient and stability, respectively. The empirical coefficients ${\alpha}$, ${\beta}$ and c depend on the magnitude of vertical components and stability, i.e., through thermocline intensity. The study indicates that the diffusivity of the surface mixed layer is (K$\sub$z/)=300∼1,200$\textrm{cm}^2$/sec, the thermocline layer is (K$\sub$z/)= 50∼200$\textrm{cm}^2$/sec and the cold layer is (K$\sub$z/)=200∼600$\textrm{cm}^2$/sec based on near- minimum least-squares error estimates from the regression analysis. An important result of our study comes out that the model is in accordance with the general trends of the effect of stability on the vertical turbulent diffusion coefficients in the case of shallow and strongly stratified channel.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.42-50
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• 2002

The duration and H/V ratio(the amplitude ratio of the horizontal to vertical components) of ground motions caused by earthquakes in southern Korea are analyzed. Total 329 seismograms of horizontal component recorded at hypocentral distances of 10 to 350 km from 27 earthquakes with local magnitude 2 to 4 are used for the analysis. Simplified relation between the duration of ground motion( $T_{d}$) and the ratio($\chi$) of Arias intensity( $I_{A}$) and squared maximum acceleration($\alpha$$_{max}$$^{2}$) is determined to be $T_{d}$ = 3.423$\chi$$^2$+ 8.200$\chi$ + 0.029, which is useful for the estimation of the duration in southern Korea. There are three distinct distance ranges with different linear variations of the duration in hypocentral distance. They are distance intervals of 10~80km, 80~140km, and the distance greater than 140km. The duration in southern Korea shows clear proportionality to the local magnitude at magnitudes greater than 3.1. The value 1.37 of the H/V ratio obtained in southern Korea is similar to the value 1.4 of ENA(Eastern North America). The H/V ratio in southern Korea increases in the frequency range from 0.3 to 10Hz. The duration and H/V ratio of ground motions derived in this study could be used in the stochastic simulation of strong ground motion.ion.n.n.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.47-51
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• 2015

Ground Level Enhancements (GLEs) in cosmic ray intensity observed during the period of 1997-2012 have been studied with energetic solar features and disturbances in solar wind plasma parameters and it is seen that all the GLEs have been found to be associated with coronal mass ejections, hard X-ray solar flares and solar radio bursts. All the GLEs have also been found to be associated with sudden jumps in solar proton flux of energy of ${\geq}60Mev$. A positive correlation with correlation coefficient of 0.48 has been found between the maximum percentage intensity (Imax%) of Ground Level Enhancements and the peak value of solar proton flux of energy (${\geq}60Mev$). All the Ground Level Enhancements have been found to be associated with jumps in solar wind plasma velocity (JSWV) events. A positive correlation with correlation coefficient of 0.43 has been found between the maximum percentage intensity (Imax %) of Ground Level Enhancements and the peak value of solar wind plasma velocity of associated (JSWV) events. All the Ground Level Enhancements have been found to be associated with jumps in solar wind plasma pressure (JSWP) events. A positive correlation with correlation coefficient of 0.67 has been found between the maximum percentage intensity (Imax %) of Ground Level Enhancements and the peak value of solar wind plasma pressure of associated (JSWP) events and of 0.68 between the maximum percentage intensity (Imax %) of Ground Level Enhancements and the magnitude of the jump in solar wind plasma pressure of associated (JSWP) events.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.74-74
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• 2010

The aqua-plasma is the non-thermal plasma in electrical conductive electrolyte by generates the vapor film layer on the immersed metal electrode surface. This plasma can generate the hydroxyl radical by dissociate the water molecule with the plasma electron. To develop the plasma discharge device for high efficiency in the hydroxyl radical generation, proper model for estimation of plasma power is necessary. In this work, the 1-D spherical model was developed, considering temperature dependence material constants. The relation between the plasma power and hydroxyl generation was also studied by the comparison between the optical emission intensity from the hydroxyl radical using monochromator and estimated plasma power. First, the thickness of vapor layer thickness was estimated using the Navier-Stokes fluid equation in order to calculate the discharge E-field inside vapor layer. Using the E-field magnitude and power balance on the plasma generation, it was possible to estimate the plasma power. The plasma power was assumed to uniformly fill the vapor layer and the temperature of vapor layer was fixed in the boiling temperature of electrolyte, 375K. In the experiment, the aqua-plasma was discharged in the saline by applied the voltage on the bipolar electrode. The range of applied voltage was 234 to 280V-rms in the frequency of 380 kHz. Two type electrodes were produced with two ${\Phi}0.2$ tungsten. The plasma power was estimated from the V-I signal from the two high voltage probes and current probe. The estimated plasma power agreed with the profile of emission intensity when the plasma discharged between the metal electrode and vapor layer surface. However, when the plasma discharged between the metal electrodes, the increasing rate of emission intensity was lower than the increase of plasma power. It implies that the surface reaction is more sufficient rather than the volume reaction in the radical generation, due to the high density of water molecule in the liquid.

• Geomechanics and Engineering
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• v.22 no.1
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• pp.49-63
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• 2020

Studying the critical response characteristics of box culverts with diverse geometrical configurations under seismic excitations is a necessary step to develop a reasonable design method. In this work, a numerical parametric study is conducted on various soil-culvert systems, aiming to highlight the critical difference in the seismic performances between three- and four-sided culverts. Two-dimensional numerical models consider a variety of burial depths, flexibility ratios and foundation widths, assuming a visco-elastic soil condition, which permits to compare with the analytical solutions and previous studies. The results show that flexible three-sided culverts at a shallow depth considerably amplify the spectral acceleration and Arias intensity. Larger racking deformation and rocking rotation are also predicted for the three-sided culverts, but the bottom slab influence decreases with increasing burial depth and foundation width. The bottom slab combined with the burial depth and structural stiffness also significantly influences the magnitude and distribution of the dynamic earth pressure. The findings of this work shed light on the critical role of the bottom slab in the seismic responses of box culverts and may have a certain reference value for the preliminary seismic design using R-F relation.

• Journal of the Korean Society of Safety
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• v.7 no.1
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• pp.20-29
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• 1992

Effects of strain hardening exponents on the retardation behavior of fatigue crack propagation are experimentally investigated. The retardation of fatigue crack propagation seems to be induced by the crack closure at crack tip. The phenomenon of crack closure becomes remarkable with the increment of strain hardening exponent and magnitude of percent peak load. The ratio of crack growth increment(a$\_$d//w$\_$d/) is influenced by a single overloading (a$\_$d/) and estimated plastic zone size (W$\_$d/=2r$\_$y/) is increased according with the increasing of strain ha.dening exponents. The number of retarded crack growth cycles were (N$\_$d/) decreased as the baseline stress intensity factor .ange( K$\_$b/) was increased. Within the limitation of these experimental results obtained under the single overload, an empirical relation between crack retardation ratio (Nd/N＊), strain hardening exponent (n) and percent peak load (％PL) has been proposed as; Nd/N＊＝ exp [PL $.$ PL$.$A(n)＋B(n) ] where, A(n)＝${\alpha}$n＋${\beta}$, B(n)＝${\gamma}$n＋$\delta$, PL＝％PL/100 and ${\alpha}$＝0.78, ${\beta}$＝0.54, ${\gamma}$＝0.58 and $\delta$＝-0.01, It is interesting to note that all these constants are identical for materials such as aluminum(A3203), steel(S4SC), steel(SS41) and stainless steel(SUS316) used in this experimental study.