• Journal of the Korean Association of Geographic Information Studies
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• v.2 no.2
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• pp.9-14
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• 1999

This paper describes an algorithm for the correction of major radiometric errors shown in MEIS (Multi-spectral Earth Imaging System) images on board KITSAT-3. MEIS images contain various radiometric errors as also shown in the images obtained from other remote sensing sensors. This paper introduces the two major radiometric error sources shown in MEIS images and the corresponding correction algorithm. The proposed algorithm was integrated to an operational preprocessing software and validated by applying the algorithm to several tens of MEIS images. This algorithm will therefore applied operationally to raw MEIS images before they are distributed to users.

• Journal of the Optical Society of Korea
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• v.17 no.6
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• pp.543-547
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• 2013

A temperature dependent (10K-290K) photoluminescence (PL) study for two differently prepared ZnO thin films (as-grown and O-plasma treated) is presented. Four characteristic peaks were identified for both samples: (i) neutral donor-bound excitons ($D^oX$), (ii) two electron satellites (TES), (iii) phonon replica of $D^oX$ ($D^oX$-1LO), and (iv) donor-acceptor pair transition (DAP). As the sample temperature increased, $D^oX$-1LO and DAP transitions became indistinct. This was accompanied by newly-rising emission of free electron-acceptor transitions (e, $A^o$). The spectral evolution with temperature for as-grown samples also showed the optical emission from free excitons, which became dominant at higher temperatures. Some features related to O-plasma were identified in PL spectra: (i) different positions of TES transitions (28meV lower than $D^oX$ for as-grown samples and 35meV for O-plasma treated samples), (ii) the decrease of spectral intensity in both emissions of $D^oX$ and DAP after O-plasma treatment, and (iii) no noticeable transition from free excitons after the O-plasma treatment.

• Mass Spectrometry Letters
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• v.13 no.4
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• pp.106-114
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• 2022

A rapid and reliable approach to the identification of microorganisms is a critical requirement for large-scale culturomics analysis. MALDI-TOF MS is a suitable technique that can be a better alternative to conventional biochemical and gene sequencing methods as it is economical both in terms of cost and labor. In this review, the applications of MALDI-TOF MS for the comprehensive identification of microorganisms and bacterial strain typing for culturomics-based approaches for various environmental studies including bioremediation, plant sciences, agriculture and food microbiology have been widely explored. However, the restriction of this technique is attributed to insufficient coverage of the mass spectral database. To improve the applications of this technique for the identification of novel isolates, the spectral database should be updated with the peptide mass fingerprint (PMF) of type strains with not only microbes with clinical relevance but also from various environmental sources. Further, the development of enhanced sample processing methods and new algorithms for automation and de-replication of isolates will increase its application in microbial ecology studies.

• The Pure and Applied Mathematics
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• v.11 no.1
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• pp.51-61
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• 2004

We find an easier formula to compute Hausdorff and packing dimensions of a subset composing a spectral class by local dimension of a self-similar measure on a self-similar Cantor set than that of Olsen. While we cannot apply this formula to computing the dimensions of a subset composing a spectral class by local dimension of a quasi-self-similar measure on a self-similar set on the way to a perturbed Cantor set, we have a set theoretical relationship between some distribution sets. Finally we compare the behaviour of a quasi-self-similar measure on a self-similar Cantor set with that on a self-similar set on the way to a perturbed Cantor set.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.623-626
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• 2003

Image analysis was performed with two color systems, Red-Green-Blue (RGB) values and normalized Hue-Saturation-Intensity (HSI). We conducted field studies in Cheongju to determine canopy spectral reflectance and digital image analysis of rice. Spectral reflectance measurements made with a portable spectrometer(LI-1800) correlated with growing stage and digital images for rice. Images in which the color was specified by the common RGB coordinates could be used when there was a sharp contrast between the color of the rice and that of the field soil. In the absence of sharp contrast, identification of the rice covered area was much easer after the color had been transformed into HSI coordinates. This study introduced fundamental theories in digital image analysis and applied that for field situations rice.

• Speech Sciences
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• v.12 no.1
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• pp.27-35
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• 2005

Differential instrumentation for the diagnoses of individuals with Cleft palate has been used to objectively measure speech problems. The Cepstrum Method was used to study the vocal tract transfer function. The vocal tract transfer function and the source spectrum should be considered in the evaluation of nasal resonance. The aim of this study was to collect quantitative data on the acoustic Instrumentation used for evaluating hypernasality. Normal subjects (9 male, 21 female; 37 male children, 20 female children) and individuals with VPI (13 male, 8 female; 16 male children, 9 female) participated in this study. The vowel /i/ was selected to gauge the severances of hypernasality Spectral and Cepstral studies using CSL was used to identify the acoustic characteristics. Cepstrum analysis shows significant differences in quefrency and amplitude. The quefrency of normal groups was shorter than that of the VPI groups, while the amplitude of normal groups was lower than that of the VPI groups. This may have significance in the evaluation 'of nasal resonance.

• Speech Sciences
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• v.6
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• pp.25-32
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• 1999

Not only Korean scholars but also many scholars in the field of phonetic science were interested in Korean forced sounds from the viewpoint of general phonetics as a way to clarify the process of production and the physical characteristics of speech sounds. The author also tried to elucidate the characteristics of Korean forced sounds using the sound spectrograph (Umeda & Umeda 1965). Over the past 30 years since this study, many scholars have analyzed these sounds from various standpoints resulting in copious amounts of literature. In this paper, the author critically examined the results of previous studies on this subject dealing with VOT, spectral characteristics, fundamental frequency, states of glottis obtained from fiber-optic investigations, and patterns of tongue-palate contact acquired from observation by use of dynamic palatograph. These points were discussed in relation to the author's field of investigation.

• Earthquakes and Structures
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• v.7 no.6
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• pp.895-908
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• 2014

The main objective of critical excitation methods is to reveal the worst possible response of structures. This goal is accomplished by considering the uncertainties of ground motion, which is subjected to the appropriate constraints, such as earthquake power and intensity limit. The concentration of this current study is on the theoretical optimization aspect, as is the case with the majority of conventional critical excitation methods. However, these previous studies on critical excitation lead to a discontinuous power spectral density (PSD). This paper introduces some critical excitations which contain proper continuity in frequency domain. The main idea for generating such continuous excitations stems from the combination of two continuous functions. On the other hand, in order to provide a non-stationary model, this paper attempts to present an appropriate envelope function, which unlike the previous envelope functions, can properly cover the natural earthquakes' accelerograms based on multi-peak conditions. Finally, the proposed method is developed into the multiple-degree-of-freedom (M.D.O.F) structures.

• The Journal of the Acoustical Society of Korea
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• v.5 no.1
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• pp.24-34
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• 1986

Recently, as the noise problems of mechancial structures have been more serious, much studies are being carried out on the identification of noise sources and the reduction of noise level. In this paper, as the application of frequency analysis, the multi-dimensional spectral analysis method is applied to daisy wheel printer to identify the noise sources, and the relationship between sound pressure and vibration of printer is found in narrow and overall frequency range. The results of this study are compared with those of frequency response function method, thus, the applicability of multidimensional spectral analysis method is verified. It can be found, in a overall frequency range, that the vibration of platen have the worst effect on noise level, and the noise level reduction of 6dB, 7.9dB is obtained by changing the platen thickness to 2mm, 4mm, respectively.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2003.04a
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• pp.157-162
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• 2003

중저해상도 광학영상의 순간시야각(instantaneous filed of view -IFOV)에 포함되는 공간에는 반사특성이 상이한 두 개 이상의 지표물이 존재하는 경우가 대부분이다. 영상분류와 같은 기존의 영상처리기법에서는 하나의 화소가 단일의 지표물을 대표한다는 가정에서 접근하였으나, 최근 화소의 혼합정도를 세분하는 분광혼합분석(spectral mixture analysis)기법이 개발되고 있다. 분광혼합분석법을 이용하여 혼합된 화소에 포함된 지표물을 분해(unmixing) 하고 그 효과를 분석하고자 하여 경기도 광릉국립수목원의 시험림 지역을 대상으로 Landsat-7 ETM＋영상을 이용하여 선형혼합 모델을 적용하였고, 그 결과 각각의 화소를 6개의 End-member의 혼합비로 구분하였다. Endmember의 비율을 나타낸 영상을 분석하여 점유비율에 따른 활엽수와 침엽수의 구분을 할 수 있었고, 각 임상별의 특징도 얻을 수 있었다. 특히 침엽수의 경우 그림자의 효과가 높다는 특성도 파악 할 수 있었다. 분광혼합분석법은 기존의 전통 분류방법과는 달리 다양한 산림의 정보를 추출해 낼 수 있다.