• Publications of The Korean Astronomical Society
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• v.27 no.4
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• pp.291-292
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• 2012

We select infrared-luminous galaxies by cross-matching the SDSS spectroscopic sample of galaxies with the WISE all-sky survey catalog. Based on photometric data points covering from SDSS u-band to WISE $22{\mu}m$, their spectral energy distributions (SEDs) are separated into AGN, elliptical, spiral, and irregular galaxy components. The derived luminosities of spiral galaxy and AGN are well correlated with $H{\alpha}$ and [OIII] line luminosities, respectively. Most galaxies are dominated by young stellar populations even for optical AGNs, but at least 10% of optical non-AGNs appear to harbor buried AGNs. The AGN contribution increases dramatically with the total luminosity. These results show that the SED decomposition is successful and is useful to understand the true nature of dusty galaxies.

• ETRI Journal
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• v.19 no.2
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• pp.35-47
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• 1997

A power amplifier operating at 3.3 V has been developed for CDMA/AMPS dual-mode cellular phones. It consists of linear GaAs power MESFET's, a new gate bias control circuit, and an output matching circuit which prevents the drain terminal of the second MESF from generating the harmonics. The relationship between the intermodulation distortion and the spectral regrowth of the power amplifier has been investigated with gate bias by using the two-tone test method and the adjacent channel leakage power ratio (ACPR) method of CDMA signals. The dissipation power of the power amplifier with a gate bias control circuit is minimized to below 1000 mW in the range of the low power levels while satisfying the ACPR of less than -26 dBc for CDMA mode. The ACPR of the power amplifier is measured to be -33 dBc at a high output power of 26 dBm.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.83-84
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• 2011

초분광 영상은 기존의 다중분광 영상보다 많은 밴드를 통해 넓은 범위의 파장 영역에 대한 반사율을 담고 있는 고차원 데이터이다. 이와 같은 고차원 데이터를 기존의 R-Tree, X-Tree와 같은 다차원 색인 방법을 사용하게 되면 차원의 저주(Course of Dimensionality)라는 문제가 발생한다. 본 논문에서는 차원의 저주 문제를 해결하기 위해 피라미드 기법을 사용하여 초분광 영상 라이브러리의 색인을 구축하였다. 파라미드 기법은 D차원의 데이터를 2D차원의 피라미드에 사상하고, B+-트리를 이용하여 1차원적으로 색인하는 방법이다. 실험 결과 스펙트럼 매칭을 위한 영역질의 방법이 후보자 추출 시간, 데이터 접근 빈도 측면에서 순차적 접근 방법보다 좋은 성능을 나타냈다.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1440-1442
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• 2007

In this work, we have modeled and fabricated microcavity-enhanced OLED using the 1-dimensional distributed Bragg reflector model (DBR). Results show that simulated spectrum intensity of microcavity OLED increased more than 30% compared to the conventional OLED, by use of DBR with $TiO_2$ and $SiO_2$. Spectral change of green and blue emission was expected to give the deeper color. The experimental design and characterization as well as the matching with simulated properties were performed for microcavity OLED for actual application.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2003.04a
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• pp.182-186
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• 2003

일반적으로 영상은 공간, 분광 및 시간 해상력을 바탕으로 고해상과 저해상 영상으로 구분된다. 최근 IKONOS 와 QuickBird 등 공간해상력이 1m 이하인 위성 영상들이 국내에 공급되어 바야흐로 고해상 위성영상을 이용한 다양한 활용분야들이 연구되고 있다. 이에 반하여 고분광해상력을 갖는 하이퍼스펙트럴 영상에 대한 연구는 미흡한 실정이다. 국제적으로는 항공기탑재 센서들을 이용한 다양하고 광범위한 조사분석 연구가 이루어지고 있으나, 국내에서는 장비와 관심의 부재로 인하여 초기적인 연구 단계에 있는 실정이다 하이퍼스펙트럴 센서는 환경, 지질, 목표물 인식 분야에 있어 많은 관심을 받고 있으며 위성탑재 초다중분광센서가 운용되기 시작하면서 연구의 활성화가 더욱 기대되고 있다. 본 연구에서는 EO-1 위성의 Hyperion 센서 데이터를 이용하여 노이즈 제거를 위한 영상 전처리 과정을 실시하고 분광특성에 따른 무감독 분류를 통한 인덱싱 기법과 널리 알려진 분광 라이브러리를 활용한 대상물, 특히 인공지물 추출 기법을 실험하였다. 이를 위하여 MNF(Maximum/Minimum Noise Filtering) 변환 및 분광 매칭(Spectral Matching) 기법, 분광 라이브러리 처리 등을 수행하였다. 결과의 비교를 위하여 동일 지역의 Landsat ETM+ 데이터를 이용하여 상호비교를 통한 검증작업으로서 그 성과를 판단하였다.

• Journal of the Optical Society of Korea
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• v.14 no.4
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• pp.420-423
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• 2010

We fabricated 1 mm-thick periodically-poled lithium niobate (PPLN) crystals by using a high-voltage amplifier for standard electric field poling combined with a voltage multiplier. Furthermore, two 1 mm-thick PPLNs were directly bonded to make a 2 mm-thick PPLN. The large aperture allowed broad angular tuning, and a broad spectral range of quasi-phase matched second-harmonic generation can be achieved in a single channel. High-power applications are also expected.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.999-1004
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• 2002

This paper presents the color displays using more than three primary colors, for the reproduction of wider color gamut, and high-fidelity color reproduction. First, Natural Vision system, which is currently under development for the natural color reproduction in visual telecommunication applications, is introduced, The natural vision is based on spectrum instead of trichromatic color space, and enables high-fidelity color reproduction using multispectral and multiprimary technologies. Then, sixprimary color projection displays using LCD and DLP, and a four-primary color flat panel display are shown. It is experimentally demonstrated that the color gamut becomes much larger than conventional RGB-based display. In addition, it is proved that the spectral color reproduction using multiprimary display suppresses the influence of observer metamerism, and as a result, the color matching between the display and the real object is well improved.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.476-477
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• 2009

The smallest green laser containing a built-in temperature controlling unit has been demonstrated. The device volume was just 0.5 cubic centimeters, which is nearly the same size as existing red and blue diode lasers, has an electrical-to-optical conversion efficiency of 10% and 150 mW power output. Furthermore as an alternative approach for compact green laser development, a quasi-phase matching method with wide spectral bandwidth for the reduction of speckle noise will be presented.

• Journal of the Optical Society of Korea
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• v.13 no.1
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• pp.158-165
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• 2009

We present cross-correlation frequency-resolved optical gating (XFROG) measurements of supercontinuum pulses generated by using a photonic crystal fiber (PCF), and ultraviolet (UV) pulses generated by frequency doubling of infrared ultra-short pulses. Since supercontinuum pulses have broad spectra, XFROG measurement typically requires using an extremely thin nonlinear crystal which has a thickness of sub-ten microns. Instead of using such a thin crystal, we employed a relatively thick crystal which was mounted on a galvanometer in order to achieve a phase-matching over the whole spectral bandwidth of the supercontinuum pulses by a crystal-dithering technique. Experimental results of the retrieved phase and intensity were in fair agreement with the independently measured data.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.247-248
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• 2007

본 논문에서는 이미지 센서의 Channel Spectral Sensitivity 특성과 CIE-Color Matching Function과의 관계를 고려하여, Color를 재구성함으로써 기존 영상의 색 정보를 그대로 복원하고, Color Error를 줄이는 방법을 제안한다. 특히 색변환 과정 중 Color Error를 줄일 때, 영상의 Edge와 Noise를 판별하여 Noise boost-up을 방지하고, 화질을 개선하는 방안을 제시한다.