• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.37-44
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• 1999

Spectral characteristic of Kyeongju earthquake occurred on the June 2, 1999 with magnitude 3,4 is analyzed. It is guessed that the stress energy release of source within relatively short period caused the ground near the epicenter to vibrate with large amplitude for the magnitude and predominantly high frequency. The cumulative absolute velocity and average spectrum acceleration are 0.034 gsec and 0.118g, respectively lower than threshold values of potential earthquake damage which is consistent with the investigation of damage in field. The analysis of the acceleration records of Kyeongju earthquake shows the need to develop the ration criterion for the determining the operating basis earthquake of nuclear power plant.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.9
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• pp.1968-1974
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• 1997

In this paper, the spectral domain approach is employed to investigate the characteristics of symmetrical and asymmetrical broadside-coupleed coplanar waveguides(BSC-CPW). These structures have large even(c)-odd(.pi.) mode-velocity ratio, suitable for wide-band and tight-coupling microwave circuit design. Efficient design parameters can be obtained from the effective dielectric constants and characteristic impedances calculated by varying the strip widths and slot widths in the BSC-CPW structure.

• Journal of the Optical Society of Korea
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• v.14 no.3
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• pp.190-198
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• 2010

A set of radiative transfer software named CART (Combined Atmospheric Radiative Transfer) has been developed to rapidly calculate atmospheric transmittance and background radiance. The spectral resolution of CART is $1cm^{-1}$, and the spectral region covers from 1 to $25000cm^{-1}$. CART has five characteristic features, and it can be applied to many fields. The features and applications of CART are summarized in detail.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2294-2296
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• 2005

Multilayer microstrip lines are an integral part of an MMIC. This paper presents an analysis of multilayer GaAs-MMIC microstrip line using a spectral domain method(SDM) taking into account the effect of the variation in the thickness of various layers of substrates on the characteristic impedance and the effective dielectric constant of the line. This work is expected to be useful in GaAs foundries for accurate CAD modelling of the microstrip lines up to 40GHz.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.2
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• pp.30-39
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• 1999

In this paper, we have proposed a novel method which can compose a reflected signal of the underwater target. The synthesis of the reflected signal in the target, the synthesized signal being similar to the characteristics of the reflected signal in the real target, is used the highlight model at the specific points of the target. We suggest the synthesis method of the reflected signal of the target using the pulsewidth variation and each other doppler effect at the highlight point, and compare the composed signal by the proposed method with that by conventional one. Simulation results show that the composed signal using the proposed method and the reflected signal of the real target is similar to the spectral characteristics.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.576-578
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• 2003

Hyperspectral image divides VNIR region to over 200 bands which can show continuous spectrum with 10 nm spectral resolution. This property is useful in geology where a spectral feature which is decided by chemical compositions and crystalline structures is recorded well. While this field has been studied variously in foreign countries, the studies are in the early stage in Korea. In this study, characteristic materials associated with AMD were classified by using EO-1 HYPERION data which is a spaceborne hyperspectral image and topographical map and DEM and geochemical map were analyzed in conjunction with the image in order to examine that classified minerals are secondary minerals by AMD.

• Bulletin of the Korean Chemical Society
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• v.17 no.11
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• pp.1004-1009
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• 1996

The interactions between a rod-coil liquid crystalline oligomer, ethyl 4-[4'-oxy-4-biphenylcarbonyloxy]-4'-biphenylcarboxylate with poly(ethylene oxide) (DP=12) (12-4) and LiCF3SO3 have been characterized by using Raman spectroscopy. Band assignments were made comparing the spectrum of 12-4 with those of the poly(ethylene glycol) monomethyl ether(PEGME) (Mw=550) and the ethyl-4'-hydroxybiphenyl-4-carboxylate (EHBPC), which are the coil and mesogen analogues, respectively. Analyzing characteristic bands of the 12-4-salt complex, we have found that the bands belonging to the coil and mesogenic units are changed in both intensities and frequencies. The spectral changes were interpreted from the viewpoint of the complexation between 12-4 and the Li+ ion. However, the possibility that the spectral changes in the mesogenic unit are not due to the complexation with the Li+ ion, but due to the conformational changes by the intercalation of nondissociated LiCF3SO3, is not ruled out.

• Bulletin of the Korean Chemical Society
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• v.15 no.3
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• pp.193-197
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• 1994

Due to possibility of visual observation of phase transformations and processes during solidification, the transparent binary alloy models are important in materials and metallurgical sciences. As such, phase diagram, linear velocity of crystallization, microstructure and spectral behaviour of binary organic systems of benzidine with resorcinol and catechol involving formation of addition compound with congruent melting point have been studied. While their phase diagrams show the formation of two eutectics and a 1:2 (B:RC, B:CT) addition compound in each case, the crystallization data obey the Hillig-Turnbull equation. The microstructural investigations give the characteristic morphology of the eutectics and the addition compounds, the spectral studies suggest intermolecular hydrogen bonding between two components forming the molecular complex.

• The Journal of the Acoustical Society of Korea
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• v.24 no.7
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• pp.402-409
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• 2005

In this paper. we propose a coding method using a matching pursuit algorithm in a strongly periodic highband signal. Also. we propose an efficient quantizer for the estimated parameters : spectral magnitude and phase. Based on the error concealment principle and sinusoidal model. the MP algorithm requires the high-precision pitch period estimation. To estimate more accurate pitch period. the refined pitch obtained from lowband speech is used. which increases the efficiency of bit allocation. The spectral magnitude parameters are quantized by the method which is combined with MDCT (Modified Discrete Cosine Transform) and multi-stage structure. The spectral phase quantizer uses the $2{\pi}$ modular characteristic of phases and the weighted function by spectral magnitudes. To evaluate the efficiency of the proposed method. we applied it to analysis-by-synthesis system. Furthermore we suggest the possibillity of scalable wideband speech codecs based on band-split structure.

• The Journal of the Acoustical Society of Korea
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• v.23 no.8
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• pp.576-582
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• 2004

A computer code that is based on the Pseudo-spectral finite difference algorithm using staggered grid is developed for the wave propagation modeling in the time domain. The advantage of a finite difference approximation is that any geometrically complicated media can be modeled. Staggered grids are advantageous as it provides much more accuracy than using a regular grid. Pseudo-spectral methods are those that evaluate spatial derivatives by multiplying a wavenumber by the Fourier transform of a pressure wave-field and performing the inverse Fourier transform. This method is very stable and reduces memory and the number of computations. The synthetic results by this algorithm agree with the analytic solution in the infinite and half space. The time domain modeling was implemented in various models. such as half-space. Pekeris waveguide, and range dependent environment. The snapshots showing the total wave-field reveals the Propagation characteristic or the acoustic waves through the complex ocean environment.