• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.05a
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• pp.222-227
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• 2001

The time simulation of slow drift motions of moored FPSO in waves is presented. The equation of motion based on Cummin's theory of impulse responses are employed, and are consisted of horizonal plane -surge, sway and yaw. The added mass coefficients, wave damping coefficients, first order wave exciting forces and the second order wave drift forces involved in the equations are obtained from a three-dimensional panel method in the frequency domain. The mooring lines are modeled quasistatically as catenary for chains and touchdown. As for numerical example, time domain analyses are carried out for a box-type FPSO in long crest irregular wave condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.870-873
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• 2001

The electron drift mobilitity of poly(4,4'-cyclohexylidenediphenyl carbonate)(PC-Z) doped with 3,5-dimethyl-3',5'-di-t-butylstilbenequinone(MBSQ) was measured by the time-of-flight technique. Energy gap of the polymer doped with 25wt% of MBSQ was 3.1 eV. The electron drift mobility was 2.98${\times}$10$\^$-6/$\textrm{cm}^2$/V$.$s at 293K. The electric field and temperature dependences of the electron drift mobility were discussed with Poole-Frenkel and Arrhenius formulations. The activation energy(E$\_$0/), Poole-Frenkel coefficient(${\beta}$) and effective temperature(T$\_$eff/) of the mobility are 0.815 eV, 1.73${\times}$10$\_$-4/ eV$.$cm$\^$1/2//V$\_$1/2/ and 6.43${\times}$10$^2$K, respectively.

• Journal of Ocean Engineering and Technology
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• v.14 no.4
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• pp.1-8
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• 2000

The time simulation of motion responses of dolphin-moored BMP in waves is presented. The equation of motion based on Cummin's theory of impulse responses are employed, and solved in time domain by using the Newmark $\beta$ method. The hydrodynamic coefficient and first order wave exciting forces involved in the equations are obtained from a three-dimensional panel method in the frequency domain. The second order wave drift forces and mooring for dolphin system are taken into account. As for numerical example, time domain analysis are carried out for a BMP in irregular wave condition.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.205-206
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• 2009

This study deals with the viscoelastic damper system with displacement-amplification unit (DAU) which can maximize the effectiveness of a damper system in controlling seismic response of a building by amplifying story drift induced to damper. DAUs in this study were analyzed to be able to amplify the displacement 2 to 4 times greater than the original story drift. The efficiency of each DAU was expressed by $\beta$ (DAU ratio) and examined in this analytical study.

• Communications for Statistical Applications and Methods
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• v.19 no.5
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• pp.639-646
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• 2012

The exponential continuous time GARCH(p,q) model for financial assets suggested by Haug and Czado (2007) is considered, where the log volatility process is driven by a general L$\acute{e}$vy process and the price process is then obtained by using the same L$\acute{e}$vy process as driving noise. Uniform ergodicity and ${\beta}$-mixing property of the log volatility process is obtained by adopting an extended generator and drift condition.

• Journal of the Korean Data and Information Science Society
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• v.22 no.6
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• pp.1233-1240
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• 2011

An augmented asymmetric power GARCH(p, q) process is considered and conditions for stationarity, geometric ergodicity and ${\beta}$-mixing property with exponential decay rate are obtained.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.2
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• pp.133-142
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• 2016

KOMPSAT-3A (KOrea Multi-Purpose SATellite-3A) was launched in March 25 2015 with specification of 0.5 meters resolution panchromatic and four 2.2 meters resolution multi spectral sensors in 12km swath width at nadir. To better understand KOMPSAT-3A positional accuracy, this paper reports a test result on the accuracy of recently released KOMPSAT-3A beta test images. A number of ground points were acquired from 1:1,000 digital topographic maps over the target area for the accuracy validation. First, the original RPCs (Rational Polynomial Coefficients) were validated without any GCPs (Ground Control Points). Then we continued the test by modeling the errors in the image space using shift-only, shift and drift, and the affine model. Ground restitution accuracy was also analyzed even though the across track image pairs do not have optimal convergence angle. The experimental results showed that the shift and drift-based RPCs correction was optimal showing comparable accuracy of less than 1.5 pixels with less GCPs compared to the affine model.

• Journal of the Korean earth science society
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• v.41 no.4
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• pp.344-355
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• 2020

Tropical cyclone scale vortices and associated Rossby waves were investigated numerically using high-resolution barotropic models on the global domain. The equations of the barotropic model were discretized using the spectral transform method with the spherical harmonics function as orthogonal basis. The initial condition of the vortex was specified as an axisymmetric flow in the gradient wind balance, and four types of basic zonal states were employed. Vortex tracks showed similar patterns as those on the beta-plane but exhibited more eastward displacement as they moved northward. The zonal-mean flow appeared to control not only the west-east translation but also the meridional translation of the vortex. Such a meridional influence was revealed to be associated with the beta gyre and the Rossby wave, which are formed around the vortex due to the beta effect. In the case of the basic zonal state of climatological mean, the meridional translation speed reached the maximum value when the vortex underwent recurving.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.2
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• pp.137-146
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• 2007

Numerical analyses are performed to show the effect of stiffening facade riggers on the behavior of the structure and to investigate the optimum locations of facade riggers. Optimum locations of the facade riggers to minimize the drift at the top of the structure are obtained by maximizing the drift reduction caused by the facade riggers and are significantly influenced by the bending and shear stiffnesses of the braced frame and facade riggers. Three standard load cases of uniformal and triangularly distributed lateral loads as well as a lateral point load at the top of the structure are considered in this paper Optimum locations of facade riggers are plotted as functions of nondimensional relative stiffness parameters ${\omega}$ and ${\beta}$ for structures with one to four riggers. Although the analysis presented herein is based on certain simplifying assumptions, it is believed that the results do provide sufficiently accurate information for determining the optimum locations of facade riggers in highrise structures.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.3
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• pp.47-53
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• 2001

When a ship advancing in waves is subjected to impact forces or irregular forces, the motion analyses for ship are convenient for being calculated in the time domain. The added mass, wave damping coefficients, wave exciting forces and mean drift forces are calculated by 3-Dimensional panel method used the translating pulsating Green function in the frequency domain and the motion equations which are considered by the memory effect due to waves are numerically solved by using the Newmark-$\beta$ method in the time domain. The motion analyses are carried out for a Series 60($C_B=0.7$) moving in irregular waves. The items of calculation are 6-degree motions, accelerations at the fore and after position, numbers of deck wetness and numbers of exposure at ship-bottom, etc. Moreover, the thrust addition in waves is examined by considering the time mean drift forces in the motion equations of time domain.