• 전자공학회논문지
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• 제50권3호
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• pp.212-218
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• 2013

본 논문에서는 SAR (Synthetic Aperture Radar) 영상에 SVD (Singular Value Decomposition) - Pseudo Spectrum 알고리즘을 적용하고 그 성능을 기존 알고리즘과 비교한다. 이 논문의 목적은 SAR 영상의 해상도 및 목표물 분해능을 높이고자 하는 것이다. 본 논문에서는 신호 성분으로 이루어진 Hankel Matrix와 SVD (Singular Value Decomposition) 방법을 사용하여 잡음에 강인하고 sidelobe이 적으며 스펙트럼 추정에서 해상도를 높인 SVD-Pseudo Spectrum 방법을 제안하였다. 또한 분해될 목표물을 모델링하여 알고리즘의 성능을 분석하고 SVD-Pseudo Spectrum 방법이 기존의 퓨리에 변환 기반 방법과 고해상도 기술 기반의 MUSIC 방법보다 더 좋은 성능을 가짐을 보인다.

• 천문학논총
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• 제29권3호
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• pp.35-44
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• 2014

In ground-based astronomical spectroscopic observations, there are many telluric absorption lines that are laid on the spectra of celestial objects. To study the physical properties of the celestial objects with these contaminated spectra, the telluric lines should be removed. A conventional method for removing the telluric lines is using the standard stellar spectrum as telluric line. In this paper, we introduce a technique to calculate synthetic telluric spectra and use them to remove telluric lines from a spectrum of a celestial object. We used Line-by-Line Radiative Transfer Model (LBLRTM) for calculating a synthetic spectrum and selected Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) model as atmospheric model. We apply our method to some spectra obtained by Bohyunsan Observatory Echelle Spectrograph (BOES) to show that the telluric lines are well removed from the observed spectra by our model within an accuracy of 2% which is close to the 1-sigma rms of the original spectra.

• The Journal of the Acoustical Society of Korea
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• 제18권1E호
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• pp.32-36
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• 1999

In the area of the speech synthesis techniques, the waveform coding methods maintain the intelligibility and naturalness of synthetic speech. In order to apply the waveform coding techniques to synthesis by rule, we must be able to alter the pitches of synthetic speech. In this paper, we propose a new pitch altering method that compensates phase distortion of the cepstral pitch alteration method with time scaling method in the time domain. This method can remove some spectrum distortion which is occurred in conjunction point between the waveforms. For performance test the spectrum distortion rate was used as objective criterion and the MOS(Mean Opinion Score) was used as subjective criterion. As a result, the spectrum distortion and MOS are obtained by 0.66% and 3.9, respectively.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1998년도 학술발표대회 논문집 제17권 1호
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• pp.159-162
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• 1998

Speech synthesis coding is classified into three categories: waveform coding, source coding and hybrid coding. To obtain the synthetic speech with high quality, the synthesis by waveform coding is desired. However, it is difficult to apply waveform coding to synthesis by syllable or phoneme unit, because it does not divide the speech into excitation and formant component. Thus it is required to alter the excitation in waveform coding for applying waveform coding to synthesis by rule. In this paper we propose a new pitch alteration method that minimizes the spectrum distortion by using the behavior of cepstrum. This method splits the spectrum of speech signal into excitation spectrum and formant spectrum and transforms the excitation spectrum into cepstrum domain. The pitch of excitation cepstrum is altered by zero insertion or zero deletion and the pitch altered spectrum is reconstructed in spectrum domain. As a result of performance test, the average spectrum distortion was below 2.29%.

• 토지주택연구
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• 제1권1호
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• pp.51-57
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• 2010

국내에서 내진설계의 중요성이 점차적으로 부각되고 있으며 이에 따라 설계 시 동적 지진해석의 수행빈도가 높아지고 있다. 동적 지진해석을 수행하기 위한 가장 중요한 입력변수 중 한가지는 입력지진파이다. 그러나 현재 국내에서는 지진학적 검토 없이 미국, 일본 등에서 계측된 강진 기록을 입력지진파로 사용하거나 주파수영역에서 생성된 인공지진파를 사용하고 있다. 국외 계측 지진기록은 지진 규모에 따라 변화하는 지속시간과 에너지를 고려할 수 없어서 국내 지진환경에는 적합하지 않으며, 주파수 영역에서 생성되는 설계응답스펙트럼에 맞춤형 인공지진파는 실제 지진기록과 주파수 특성이 상이한 문제가 있다. 본 연구에서는 이와 같은 입력지진파의 문제점을 극복하기 위하여 시간영역에서 수행되는 응답스펙트럼 맞춤형 인공지진파 알고리즘을 적용하여 입력 지진파를 생성하였다. 생성된 지진파는 계측 지진기록의 고유한 성질인 Non-stationary 특성을 보존하며 동시에 설계 응답스펙트럼과 거의 완벽한 일치성을 보이는 것으로 나타났다.

• 한국지진공학회논문집
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• 제23권2호
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• pp.89-99
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• 2019

In order to increase the seismic safety of nuclear power plant (NPP) structures, a technique to reduce the seismic load transmitted to the NPP structure by using a seismic isolation device such as a lead-rubber bearing has recently been actively researched. In seismic design of NPP structures, three directional (two horizontal and one vertical directions) artificial synthetic earthquakes (G0 group) corresponding to the standard design spectrum are generally used. In this study, seismic analysis was performed by using three directional artificial synthetic earthquakes (M0 group) corresponding to the maximum-minimum spectrum reflecting uncertainty of incident direction of earthquake load. The design basis earthquake (DBE) and the beyond design basis earthquakes (BDBEs are equal to 150%, 167%, and 200% DBE) of G0 and M0 earthquake groups were respectively generated for 30 sets and used for the seismic analysis. The purpose of this study is to compare seismic responses and seismic fragility curves of seismically isolated NPP structures subjected to DBE and BDBE. From the seismic fragility curves, the probability of failure of the seismic isolation system when the peak ground acceleration (PGA) is 0.5 g is about 5% for the M0 earthquake group and about 3% for the G0 earthquake group.

• 산업기술연구
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• 제4권
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• pp.47-53
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• 1984

The cross correlation function arc applied find the Lag time between the rainfall and runoff at Chuncheon Dam which is located the upstream of the North Han River. In the result, we think that spectrum analysis is better than synthetic unit hydrograph of Synder ar the river basin with the actual data.

• 천문학회보
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• 제41권1호
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• pp.78.2-78.2
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• 2016

There are many telluric absorption lines which are laid on the science spectrum in ground based spectroscopic observations. In especial, the IR region spectra are considerably contaminated by telluric lines. Therefore, many scientists have a difficulty in removing the telluric effect. We thus tried removing telluric lines with IGRINS data by two methods. One is using the standard stellar spectrum as telluric lines. The other adopt calculated synthetic telluric spectrum. Here we present the results of test for precise removing telluric lines on IGRINS spectra.

• Electronic Materials Letters
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• 제14권6호
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• pp.774-783
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• 2018

Full maximum-entropy mobility-spectrum analysis (FMEMSA) is the best algorithm among mobility spectrum analyses by which we can obtain a set of partial-conductivities associated with mobility values (mobility spectrum) by analyzing magnetic-field-dependent conductivity-tensors. However, it is restricted to a direct band-gap semiconductor and should be modified for materials with other band structures. We developed the modified version of FMEMSA which is appropriate for a material with a single anisotropic valley, or an indirect-band-gap semiconductor quantum-well with a single non-degenerate conduction-band valley e.g., (110)-oriented AlAs quantum wells with a single anisotropic valley. To demonstrate the reliability of the modified version, we applied it to several sets of synthetic measurement datasets. The results demonstrated that, unlike existing FMEMSA, the modified version could produce accurate mobility spectra of materials with a single anisotropic valley.

• Environmental Engineering Research
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• 제20권2호
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• pp.111-120
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• 2015

Contaminants of emerging concern (CECs) including endocrine disrupting compounds (EDCs) and pharmaceuticals and personal care product chemicals (PPCPs) have recently received more attention because of their occurrence in water bodies and harmful impacts on human health and aquatic organisms. Triclosan is widely used as a synthetic broad-spectrum antimicrobial agent due to its antimicrobial efficacy. However, triclosan detected in aquatic environment has been recently considered as one of CECs, because of the potential for endocrine disruption, the formation of toxic by-products and the development of cross-resistance to antibiotics in aquatic environment. This comprehensive review focuses on the regulations, toxicology, fate and transport, occurrence and removal efficiency of triclosan. Overall, this review aims to provide better understanding of triclosan and insight into application of biological treatment process as an efficient method for triclosan removal.