• 한국기계가공학회지
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• 제10권2호
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• pp.104-109
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• 2011

I present a method of aspheric surface profile measurement using 2nd derivative of local area profile. This method is based on the principle of curvature sensor which measures the local 2nd derivative under test along a line. The profile is then reconstructed from the data on the each point. Unlike subaperture-stiching method and slope detection method, 2nd derivative method has strong points from a geometric point of view in measuring the aspheric surface profile. The second derivative terms of surface profile is an intrinsic property of the test piece, which is independent of its position and tip-tilt motion. The curvature is measured at every local area with high accuracy and high lateral resolution by using White-light scanning interferometry.

• 한국작물학회지
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• 제53권3호
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• pp.314-319
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• 2008

Near infrared (NIR) spectroscopy was used to classify normal and artificially aged nonviable corn (Zea mays L., cv. 'Suwon19') seeds. The spectra at 1100-2500nm were scanned with normal and artificially aged single seeds and analyzed by principle component analysis (PCA). To discriminate normal seeds from artificially aged seeds, a calibration modeling set was developed with a discriminant partial least square 2 (PLS 2) method. The calibration model derived from PLS 2 resulted in 100% classification accuracy of normal and artificially aged (aged) seeds from the raw, the 1st and 2nd derivative spectra. The prediction accuracy of the unknown normal seeds was 88, 100 and 97% from the raw, the $1^{st}$ and $2^{nd}$ derivative spectra, and that of the unknown aged seeds was 100% from all the raw, the $1^{st}$ and $2^{nd}$ derivative spectra, respectively. The results showed a possibility to separate corn seeds into viable and non-viable using NIR spectroscopy.

• Journal of Ginseng Research
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• 제18권3호
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• pp.204-211
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• 1994

Three unknown ninhydrin positive substances (UK-I, UK-II and UK-III) were detected with an amino acid analyzer in a water extract of Korean red ginseng. One of them (UK-II) was isolated and determined to be maltulosyl arginine (Arg-Fru-Glc) on the basis of chemical and spectroscopic evidence. Another one (VK-III) was identified as Arg-Fru. Maltulosyl arginine, but not Arg-Fru, is a newly identified amino acid derivative. The Korean red ginseng was shown to contain more amount of maltulosyl arginine than the white ginseng. Maltulosyl arginine was found to be produced by the Mallard reaction of maltose with arginine during the heating process involved in preparation of the red ginseng. Maltulosyl arginine was found to inhibit maltase activity. Based on these results, the physiological significance of this new compound is discussed.

• Journal of Biosystems Engineering
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• 제22권2호
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• pp.247-255
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• 1997

This study was conducted to develop regression models predicting sugar and acid contents in intact fruits nondestructively by using the second derivative of absorbance spectrum measured with a spectrophotometer wavelength range of 400nm to 2, 400nm. The correlation analysis was made in wavelength range of 600nm to 1, 100nm and 600nm to 2, 400nm respectively, in order to examine the feasibility of using a real time spectrophotometer, which covers the former range, in predicting sugar and acid contents. The second derivative data of the spectrum were obtained by varying smoothing size and derivative size of the original absorbance spectrum. SAS statistical package program was used for the regression analysis. The sugar contents of Fuji apple, Shingo pear md Yumyung peach could be predicted with SEPs of 0.40, 1.17 and 0.77 respectively, in the spectrum range of 600 to 1, 100nm. The highest correlation coefficient of the titratible acidity of apple was -0.45 at 2, 346nm and regression models indicated determination coefficient less than 0.47.

• 한국컴퓨터정보학회논문지
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• 제16권2호
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• pp.61-69
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• 2011

동적계획법이 기반인 Dynamic Time Warping은 두 패턴의 유사도를 비교하기 위해 널리 사용되는 방법이다. DTW알고리즘에는 2가지 알려진 문제점이 있다. 첫 번째 문제는 DTW알고리즘은 2개의 패턴의 대응경로를 계산하면서 특이점이 발생하는 문제가 발생하게 된다. 두 번째 문제는 동적패턴의 대응경로가 올바른지 알 수 없다는 문제가 있다. 이에 본 논문에서는 DTW알고리즘의 문제에 대한 효과적인 해결을 위하여, 2차 미분 연산자를 적용한 DTW알고리즘을 제안 한다. 2차 미분 연산자의 하나인 "라플라시안오브가우시안" 연산자를 적용하여, 효과적으로 특이점에 대한 문제를 해결하고, 올바른 대응경로를 가질 수 있는 방법에 대하여 제안하고, 실험의 결과로 제안하는 알고리즘의 우수성을 증명한다.

• 한국해양공학회지
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• 제14권3호
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• pp.41-45
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• 2000

In solving the unsteady potential flow problem of the ship in waves with the panel method, in general one can consider the basic flow as the free stream or double body solution. For the double body solution, the body boundary condition has the 2nd derivatives of the velocity potential. Low order panel methods are known to suffer from the significant error in the 2nd derivatives computed at the body surface. This paper analyzes the numerical error in the 2nd derivatives for a 2-D cylinder and a 3-D sphere problem, and an extrapolation method to obtain the correct derivatives on the body surface is suggested.

• 한국군사과학기술학회지
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• 제22권2호
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• pp.224-232
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• 2019

This paper presents guidelines for the verification test on electromagnetic environmental effects of a commercial derivative military aircraft. To prove the safety-of-flight of a renovated aircraft and appropriate working of electronic system/device, E3 test and analysis at the system level should be performed prior to its operations on real warfare. For the aircraft modified with Falcon 2000S, we concentrate on intra-system EMC, EMRADHAZ (Electromagnetic Radiation Hazards), electrical bonding, P-Static as test and lightning as analysis from a airworthiness certification point of view based on MIL-STD-464, MIL-HDBK-516. As a result, it is verified that the modified aircraft has enough electromagnetic compatibility capabilities under EME(Electromagnetic Environment). In the process, test and analysis methods considering shielding effectiveness(SE) are applied.

• Journal of the Korean Wood Science and Technology
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• 제47권1호
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• pp.101-109
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• 2019

This paper examines the classification of five coniferous species, including larch (Larix kaempferi), red pine (Pinus densiflora), Korean pine (Pinus koraiensis), cedar (Cryptomeria japonica), and cypress (Chamaecyparis obtusa), using near-infrared (NIR) spectra. Fifty lumber samples were collected for each species. After air-drying the lumber, the NIR spectra (wavelength = 780-2500 nm) were acquired on the wide face of the lumber samples. Soft independent modeling of class analogy (SIMCA) was performed to classify the five species using their NIR spectra. Three types of spectra (raw, standard normal variated, and Savitzky-Golay $2^{nd}$ derivative) were used to compare the classification reliability of the SIMCA models. The SIMCA model based on Savitzky-Golay $2^{nd}$ derivatives preprocessing was determined as the best classification model in this study. The accuracy, minimum precision, and minimum recall of the best model (PCA models using Savitzky-Golay $2^{nd}$ derivative preprocessed spectra) were evaluated as 73.00%, 98.54% (Korean pine), and 67.50% (Korean pine), respectively.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1526-1526
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• 2001

To improve the accuracy of sweetness sensor in automated sorting operations, it is necessary to clarify unevenness of the sugar content distribution within fruits. And it is expected that the technique to evaluate the content distribution in fruits contribute to the development of the near-infrared (NIR) imaging spectroscopy. Sugiyama (1999) had succeeded to visualize the distribution of the sugar content on the surface of a half-cut green fresh melon. However, this method cannot be applied to red flesh melons because it depends on information of the absorption band of chlorophyll (676 nm), which is affected by the color of the fresh. The objective of this study was to develop the universal visualization method depends on the absorption band of sugar, which can be applied to various kinds of melons and other fruits. The relationship between the sugar contents and absorption spectra of both green and red fresh melons were investigated by using a NIR spectrometer to determine the absorption band of sugar. The combination of 2$\^$nd/ derivative absorbances at 902 nm and 874 nm was highly correlated with the sugar contents. The wavelength of 902 nm is attributed to the absorption band of sugar. A cooled charge-coupled device (CCD) imaging camera which has 16 bit (65536 steps) A/D resolution was equipped with rotating band-pass filter wheel and used to capture the spectral absorption images of the flesh of a vertically half-cut red fresh melon. The advantage of the high A/D resolution in this research is that each pixel of the CCD is expected to function as a detector of the NIR spectrometer for quantitative analysis. Images at 846 nm, 874 nm, 902 nm and 930 nm were acquired using this CCD camera. Then the 2$\^$nd/ derivative absorbances at 902 nm and 874 nm at each pixel were calculated using these four images. On the other hand, parts of the same melon were extracted for capturing the images and squeezed for the measurement of sugar content. Then the calibration curve between the combination of 2$\^$nd/ derivative absorbances at 902 nm and 874 nm and sugar content was developed. The calibration method based on NIR spectroscopy techniques was applied to each pixel of the images to convert the 2$\^$nd/ derivative absorbances into the Brix sugar content. Mapping the sugar content value of each pixel with linear color scale, the distribution of the sugar content was visualized. As a result of the visualization, it was quantitatively confirmed that the Brix sugar contents are low at the near of the skin and become higher towards the seeds. This result suggests that the visualization technique by the NIR imaging spectroscopy could become a new useful method fer quality evaluation of melons.

• 한국결정성장학회지
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• 제22권6호
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• pp.291-298
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• 2012

자기 조립 분자 집합체 물질인 CMPO로 표면개질 된 메조 다공성 실리케이트를 가수분해와 축합반응을 이용하여 합성하였다. 손님 물질인 CMPO는 2-(diphenylphosphoryl) acetic acid와 3-(triethoxysilyl) propan-1-amine의 아마이드 결합반응을 이용하여 합성하였으며, MCM-41, SBA-15 그리고 실리카 나노입자와 같은 다양한 메조 다공성 실리케이트는 주인물질로 채택하였다. 메조 다공성 실리케이트의 비표면적은 680 $m^2/g$~1310 $m^2/g$의 넓이로 측정되었으며 BJH 방법을 이용해서 동공의 크기를 확인한 결과 2.3~9.1 nm 범위의 다양한 크기를 가지고 있었다. 메조 다공성 실리카 중에서는 SBA-15(II)가 가장 높은 약 35 wt%의 CMPO 함유량을 나타내었다. 메조 다공성 실리케이트의 표면에 개질된 CMPO 실란 작용기와 란탄족 이온과의 접근성에 관한 연구 결과, CMPO로 개질 된 모든 흡착제의 경우 상대적으로 이온 반경이 큰 La(III)보다는 크기가 작은 Nd(III)와 Eu(III) 이온을 더 선호하였다.