• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.422-425
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• 2005

Spectral characteristics depending on soil constituents and their proportion in a soil were firstly studied for monitoring of soil contamination using hyperspectral remote sensing. The reflectance spectra of heavy metals in soils were investigated in the VIS-NIR-SWIR regions (400-2500 nm) to observe spectral variation as a function of constituents and concentrations. Commercial kaolinite soils mixed with lead, copper, arsenic, and cadmium were used as synthetic soil samples for spectral measurement. In case of copper, relatively spectrally active regions was observed with some band shift whereas other heavy metals had only simple spectral variations expected to be related to the sorption phase and the amount of metal onto kaolinite. The reflectance spectrum of each metal on kaolinite could be identified in VIS-NIR region.

• 지구물리와물리탐사
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• 제21권1호
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• pp.54-60
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• 2018

탄성파 탐사를 통해 취득된 자료는 적절한 자료처리 및 해석 과정을 거쳐 석유, 가스 자원의 부존여부를 파악하는데 활용할 수 있다. 자원의 부존여부를 지시하는 탄성파 속성은 진폭 정보로부터 도출되며, 이 때 탄성파 고유 감쇠를 표현하는 Q 값은 탄화수소 지시자로서 유용하게 사용된다. 따라서, Q 값을 산출하는 기법의 정확성이 자원 부존여부를 파악하는데 매우 중요한 역할을 한다. 본 연구에서는 수치모형실험을 통해 탄성파 감쇠를 표현하는 Q 값을 산출하고 오차율을 분석하였다. 실제 현장자료를 모사하기 위해 무작위 잡음을 추가한 자료에 대하여 스펙트럼 진폭 비교법과 최대 주파수 이동법을 이용하여 Q 값을 산출하고 오차율을 분석하였다. Q 값을 산출한 결과 무작위 잡음을 추가하여 신호대 잡음비가 90 dB 일 때는 두 가지 방법 모두 비교적 정확한 값을 산출하였으나, 무작위 잡음의 크기가 증가할 경우 최대 주파수 이동법이 스펙트럼 진폭 비교법 보다 정확한 결과를 도출함을 알 수 있었다.

• 말소리와 음성과학
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• 제8권4호
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• pp.39-47
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• 2016

While acoustic studies in the past decade documented a raised /o/ by showing their lowered first formants (F1) almost overlapped with those of high back vowel /u/, no consensus has been made in terms of how this /o/-raising affects the vowels as a system in Seoul Korean. The current study aimed to investigate the age- and gender-related differences of the relative distance among the vowels to better understand the influence of this on-going sound change on the vowel system. We measured the static and dynamic spectral characteristics (F1 and F2) of the seven Korean monophthong vowels /e a ʌ o u ɨ i/ in the spontaneous speech of Seoul Corpus, and depicted the patterns of 30 individual speakers (10 speakers in each group of teens, 20s and 40s) as a function of age and gender. The static spectral examination showed low F1 values of /o/ in the spontaneous speech corpus confirming the vowel /o/ raising, and also revealed greater F2 values of /u, ɨ/ suggesting their anterior articulations. The tendencies were stronger when the speakers were younger and female. The spectral trajectories further showed that the F1 and F2 between /o/ and /u/ were differentiated throughout the vowel mid-point although the trajectories gradually merged near the vowel mid point in the older male speakers' productions. The acoustic evidence of contrast among /o, u, ɨ/ supports that the raised /o/ is not indicative of a merger with /u/ but rather implying a chain-like vowel shift in the Seoul Korean.

• 한국통신학회논문지
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• 제41권12호
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• pp.1700-1706
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• 2016

본 논문은 동시 전송 가능한 사물지능 통신 트래픽의 수를 늘리기 위하여 doubly truncated cyclic code shift keying (DTCCSK)을 활용한 대역 확산 알로하 기법을 제안한다. 제안하는 DTCCSK는 정사각형으로 표시되는 cyclic code shift keying 코드셋의 우측과 하단을 절삭함으로써 생성 가능하며, spreading factor와 심볼 길이를 자유롭게 설계할 수 있는 특징을 가진다. 또한 DTCCSK는 대역 확산 알로하의 변복조 기법으로 주로 사용되는 direct sequence 보다 높은 주파수 효율을 보이면서도 M-ary 시그널링 기법에 비해서는 낮은 구현 복잡도로 구현이 가능하다. 본 논문은 사물지능 통신을 위해 대역 확산 알로하를 채택한 S-band mobile interactive multimedia 표준을 참고하여 시뮬레이션 환경을 구성하였고 DTCCSK의 성능을 검증하였다.

• 천문학회보
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• 제36권2호
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• pp.149.2-149.2
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• 2011

We performed the cross-correlation analysis on energy-dependent light curves of the Z-type source GX 5-1. We observed X-ray delays of a few hundred seconds between hard (16-30 keV) and soft (2-5 keV) X-ray light curves. During these phenomena, the centroid frequency of horizontal branch oscillation (HBO) was found to shift to lower or higher frequency indicating towards the dynamical movement of a Compton cloud or an inner disk front. Both eastern and western approaches were used to unfold the X-ray continuum and systematic changes were observed in soft and hard X-ray spectral components. Simultaneous energy spectral and power density spectral study shows that the production of HBOs is closely related to the Comptonizing region rather than the accretion disk. We discuss the results in the context of re-condensation of coronal material in the inner accretion disk region.

• ETRI Journal
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• 제31권2호
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• pp.228-230
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• 2009

InP-based planar waveguide 48-channel concave grating demultiplexers with a channel spacing of 0.8 nm (100 GHz) are described and demonstrated. Polarization insensitivity and flattened spectral response are successfully achieved by the introduction of a polarization compensator and a two-focus grating, respectively. The fabricated device shows a polarization-dependent wavelength shift of less than 20 pm and a -3 dB spectral width of about 0.55 nm (68.75 GHz) over all channels.

• Journal of the Optical Society of Korea
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• 제16권3호
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• pp.299-304
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• 2012

A high angular tolerance spectral filter was realized incorporating an etalon, which consists of a $TiO_2$ cavity sandwiched between a pair of Ag/Ge mirrors. The effective angle was substantially extended thanks to the cavity's high refractive index. The device was created by embedding a 313-nm thick $TiO_2$ film in 16-nm thick Ag/Ge films through sputtering, with the Ge layer alleviating the roughness and adhesion of the Ag layer. For normal incidence, the observed center wavelength and transmission were ~900 nm and ~60%, respectively; throughout the range of $50^{\circ}$, the relative wavelength shift and transmission variation amounted to only ~0.06 and ~4%, respectively.

• 전기학회논문지
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• 제67권9호
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• pp.1232-1238
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• 2018

This paper proposes methods for improving mass spectral resolution for a gas chromatograph mass spectrometer. The slope signs of the 1st and 2nd fitting functions for the ion signal block of each mass index are obtained, and the unnecessary element signals in the ion signal block are removed. The spectrum can be obtained by obtaining the second-order fitting function of the reconstructed ion signal block using only the effective ion signals. In addition, the resolution of the mass spectrum can be improved by correcting the error caused by the shift of the spectral peak position. To verify the performance of the proposed methods, computer simulations were performed using the actual ion signals obtained from the GC-MS system under development. Simulation results show that the proposed method is valid.

• Bulletin of the Korean Chemical Society
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• 제24권7호
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• pp.971-974
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• 2003

By utilizing singular value decomposition (SVD) and shift averaged Harr wavelet transform (WT) with a set of Daubechies wavelet coefficients (1/2, -1/2), a method that can simultaneously eliminate an unwanted large solvent peak and noise peaks from NMR data has been developed. Noise elimination was accomplished by shift-averaging the time domain NMR data after a large solvent peak was suppressed by SVD. The algorithms took advantage of the WT, giving excellent results for the noise elimination in the Gaussian type NMR spectral lines of NMR data pretreated with SVD, providing superb results in the adjustment of phase and magnitude of the spectrum. SVD and shift averaged Haar wavelet methods were quantitatively evaluated in terms of threshold values and signal to noise (S/N) ratio values.

• 한국잠사곤충학회지
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• 제39권2호
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• pp.169-173
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• 1997

The behavior of tyrosine(Tyr.) residue of Bombyx mori silk fiber from yellow fluorescent cocoon has been examined for the dependence of pH in aqueous silk solution under the presence of orange II salt. Through the peak separation of angular dependence of spectral pattern of 15N-Tyr. and [1-13C]-Tyr. between the fiber axis and the molecular bond direction, N-H bond in fiber as well as the orientation distribution around the fiber axis were analyzed. Also, and sericin component was obtained from these angular dependence of oriented spectral pattern. The pH dependence of the 13C NMR chemical shift of B. mori silk fibroin was examined in aqueous solution in the presince of orange II are broad at pH$\geq$7.0. However, these become sharper at pH$\geq$8.0 and remain sharp at higher pH. In these higher pH range, a chemical shift change occurs due to the deprotonation of the Tyr. side group of fibroin. At higher pH. such a hydrophobic cluster is destroyed because of the electrostatic interaction according to the deprotonation of the Tyr-OH group.