• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.213-216
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• 2005

A novel hyperspectral imaging spectrometer controlling spatial and spectral resolution individually has been proposed. This imaging spectrometer uses a zoom lens as a telescope and a focusing element. It can change the spatial resolution fixing the spectral resolution or the spectral resolution fixing the spatial resolution. Here, we report the concept of the hyperspectral imaging spectrometer with the novel zooming function and the optical design of a zoom lens as the focusing element. By using lens module and third-order aberration theory, we have presented the initial design of four-group zoom lens with external entrance pupil. And the optimized zoom lens with a focal length of 50 to 150 mm is obtained from the initial design by the optical design software. As a result, the designed zoom lens shows satisfactory performances in wavelength range of 450 to 900 nm as a focusing element in an imaging spectrometer. Furthermore, the collimator lens of the imaging spectrometer is designed through the third-order aberration correction by using an iterative process.

• 대한원격탐사학회지
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• 제26권5호
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• pp.465-475
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• 2010

분광라이브러리는 지구에 존재하는 다양한 물질의 분광반사 자료와 그에 대한 보조자료를 축적한 데이터베이스로 정의할 수 있다. 분광라이브러리는 다양한 분야에서 물질의 종류와 특성을 분석하기 위한 참조자료로 사용되고 있으며 원격탐사 분야에서는 광학영상 자료와 연계하여 토지 피복의 종류와 속성을 분류하고 더 나아가 초분광영상의 해석에 중요한 자료로 사용되고 있다. 현존 분광라이브러리는 측정항목이나 측정방법, 보조자료 등이 표준화되어 있지 않으며, 특히 국내에 직접 적용하기에는 지표물의 종류가 한정되어 있다. 이 논문은 국내 환경에 직접 적용할 수 있는 분광라이브러리를 설계하고 구축하는 과정을 인공물에 대한 분광반사측정을 실시하였고 동시에 설계된 보조자료의 항목에 대한 측정 및 조사를 실시하였다. 또한 외국에서 개발된 분광라이브러리에서 보조자료가 충실한 광물 및 암석, 토양, 물 등의 분광반사자료를 함께 포함하고 있다. 구축된 분광라이브러리의 활용성 증대와 검색의 용이성을 위해 분광라이브러리 뷰어를 개발하였다.

• 토지주택연구
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• 제6권3호
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• pp.147-152
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• 2015

현재, 국내의 내진설계기준에서 제시하고 있는 지반분류 방법과 지반 증폭계수는 깊은 기반암 조건의 미국 서부 해안지역 지반에 적합하도록 제시되어 있으므로 기반암이 약 30m 미만인 우리나라와는 다른 동적 거동을 나타낸다. 선행연구에 의하면, 말뚝 기초에 대한 원심모형 실험결과와 동적 지진 해석결과는 우리나라에서 사용하고 있는 설계스펙트럼의 가속도 값보다 주기 1.5초 부근에서는 낮게 나타나고 있다. 따라서, 본 논문에서는 원심모형 실험결과에서 얻어진 설계스펙트럼 가속도를 사용하여 구조해석을 수행하고 기존의 설계기준과 대비하여 철근 및 콘크리트의 물량 등을 상호 비교하여 아파트 골조공사의 경제성을 비교, 검토하였다. KBC-2009 기준의 Sc 지반과 SD 지반을 사용하여 구조해석 및 내진설계를 수행하고, SD에 해당하는 지반의 동적 지진 실험결과의 스펙트럼가속도(SDS)를 사용하여 구조해석 및 내진설계를 수행하여 상호 비교 고찰한 결과, 지반의 종류 SD 지반에 해당하는 연약지반의 경우라도 동적 실험 및 해석을 수행하여 지반의 스펙트럼 가속도를 산정하여 구조해석에 적용할 경우 Sc 지반과 유사한 정도의 철근 물량 값을 얻을 수 있었고, 이것은 당초 연약지반으로 고려되던 SD 지반으로 설계하는 경우에 비하여 17~23% 정도의 물량을 절감할 수 있는 것으로 나타났다.

• Journal of the Optical Society of Korea
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• 제20권4호
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• pp.515-523
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• 2016

Spectral reflectance is sparse in space, and while the traditional spectral-reconstruction algorithm does not make full use of this characteristic sparseness, the compressive sensing algorithm can make full use of it. In this paper, on the basis of analyzing compressive sensing based on the orthogonal matching pursuit algorithm, a new algorithm based on the Dice matching criterion is proposed. The Dice similarity coefficient is introduced, to calculate the correlation coefficient of the atoms and the residual error, and is used to select the atoms from a library. The accuracy of Spectral reconstruction based on the pseudo-inverse method, Wiener estimation method, OMP algorithm, and DOMP algorithm is compared by simulation on the MATLAB platform and experimental testing. The result is that spectral-reconstruction accuracy based on the DOMP algorithm is higher than for the other three methods. The root-mean-square error and color difference decreases with an increasing number of principal components. The reconstruction error decreases as the number of iterations increases. Spectral reconstruction based on the DOMP algorithm can improve the accuracy of color-information replication effectively, and high-accuracy color-information reproduction can be realized.

• 대한수학회지
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• 제51권5호
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• pp.941-953
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• 2014

In this paper, a 2-circular matrix theory is developed, and a concept of spectral radius for biorthogonal wavelet is introduced. We propose a novel design method by minimizing the spectral radius and obtain a wavelet which has better performance than the famous 9-7 wavelet in terms of image compression coding.

• 한국통신학회논문지
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• 제21권10호
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• pp.2653-2659
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• 1996

In this paper, DC-free and minimum bandwidth binary line codes with look-up table are proposed and their performances are analyzed. As results of performance analysis, the proposed codes are shown to have spectral nulls at DC and Nyquist frequency. Among the proposed codes, binary line codes of which both codeword digital sum and alternating digital sum are zero have lower code rate but better spectral characteristics. Furthermore, binary line codes which consist of all codewords including those with nonzero digital sum and alternating digital sum have worese spectral characteristics but higher code rate.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.297-303
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• 1998

The uniform hazard spectrum of Wolsong Nuclear Power plant Site is computed in order to estimate probabilistically the characteristics of spectral ground response. The spectral hazard values calculated from the seismic zoning maps proposed by eight seismologist are combined with equal weight to produce a uniform hazard spectrum. The uniform hazardd spectra corresponding to reference probabilities of 1.0 $\times$10-4/year and 1.0$\times$10-5/year are presented, which largely depend on the spectral attenuation relation. The computational results of this study contribute to verify the conservatism of the design ground spectrum of Wolsong Nuclear Power Plant.

• International Journal of Naval Architecture and Ocean Engineering
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• 제3권2호
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• pp.116-121
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• 2011

The Spectral Fatigue Analysis is representative fatigue life assessment method for vessels. This Analysis is performed generally for the whole vessel and many assessment sites. The spectral fatigue analysis is performed through the process of hydrodynamic response analysis, global structural analysis, local structural analysis and calculation of fatigue damage. In these processes, fatigue damage is affected by many variables. The representative variables are S-N curve data, wave scatter data, wave spectrum, bandwidth effect and etc. In this paper, the effects of these variables to the fatigue damage are analyzed through the spectral fatigue analysis for 170k LNGC.

• International Journal of Control, Automation, and Systems
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• 제6권3호
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• pp.378-385
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• 2008

This paper aims to present a polynomial approach to the steady-state optimal filtering for delayed systems. The design of the steady-state filter involves solving one polynomial equation and one spectral factorization. The key problem in this paper is the derivation of spectral factorization for systems with delayed measurement, which is more difficult than the standard systems without delays. To get the spectral factorization, we apply the reorganized innovation approach. The calculation of spectral factorization comes down to two Riccati equations with the same dimension as the original systems.

• Current Optics and Photonics
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• 제7권5호
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• pp.518-528
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• 2023

As an effective means of remotely detecting the spectral information of the object, the spectral calibration for the Savart polarization interference imaging spectrometer (SPIIS) is a basis and prerequisite of information quantification, and its experimental calibration scheme is firstly proposed in this paper. In order to evaluate the accuracy of the spectral information acquisition, the linear interpolation, cubic spline interpolation, and piecewise cubic interpolation algorithms are adopted, and the precision of the quadratic polynomial fitting is the highest, whose fitting error is better than 5.8642 nm in the wavelength range of [500 nm, 820 nm]. Besides, the inversed value of the spectral resolution for the monochromatic light is greater than the theoretical value, and the deviation between them becomes larger with the wavelength increasing, which is mainly caused by the structural design of the SPIIS, together with the rationality of the spectral restoration algorithm and the selection of the maximum optical path difference (OPD). This work demonstrates that the SPIIS has achieved high performance assuring the feasibility of its practical use in various fields.