• Korean Journal of Remote Sensing
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• v.34 no.4
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• pp.681-692
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• 2018

This study was performed to select the significant wavelengths for predicting the chlorophyll content of grafted cucumber seedlings using hyperspectral images. The visible and near-infrared (VNIR) images and the short-wave infrared images of cucumber cotyledon samples were measured by two hyperspectral cameras. A correlation coefficient spectrum (CCS), a stepwise multiple linear regression (SMLR), and partial least squares (PLS) regression were used to determine significant wavelengths. Some wavelengths at 501, 505, 510, 543, 548, 619, 718, 723, and 727 nm were selected by CCS, SMLR, and PLS as significant wavelengths for estimating chlorophyll content. The results from the calibration models built by SMLR and PLS showed fair relationship between measured and predicted chlorophyll concentration. It was concluded that the hyperspectral imaging technique in the VNIR region is suggested effective for estimating the chlorophyll content of grafted cucumber leaves, non-destructively.

• Polymer(Korea)
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• v.26 no.1
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• pp.80-87
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• 2002

A comparative study using electron-beam(EB) and thermal curing techniques was carried out to determine the effect of cure behavior and thermal stability of epoxy resins. In this work, benzylquinoxalinium hexafluoroantimonate(BQH) was used as a latent cationic catalyst for an epoxy resin. According to the thermogravimetric analysis(TGA), the decomposed activation energy based on Coats-Redfern method was higher in the case of thermal curing technique. This could be interpreted in terms of slow thermal diffusion rate resulted from high crosslink density of the thermally cured epoxy resin. However, the increase of hydroxyl group in the epoxy resin cured by EB technique was observed in near-infrared spectroscopy(NIRS) measurements, resulting in improving the stable short aromatic chain structure, integral procedural decomposition temperature, and finally ductile properties for high impact strengths.

• Journal of the Korean Solar Energy Society
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• v.27 no.4
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• pp.137-146
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• 2007

This study is about the passive cooling effects of three outdoor solar shading facilities as trees, pergola with wistaria vine and membrane shading structure, which are expected to provide cool spots in the summer. Field observations of measuring thermal environment of selected facilities is executed. Thermal environment measuring was categorized as short wave radiation, long wave radiation, net radiation, globe temperature, surface temperature measured by infrared camera. Heat transfer mechanism is analyzed with overall data from field measurement. Results from this study are as below; 1) Radiation balance measured on shaded surface under membrane shading structure was 17%($86W/m^2$) of the unshaded surface radiation balance($511W/m^2$). 2) Surface temperature comparison between vegetation and membrane of the shading structure is performed at 3 o'clock in the afternoon. Surface temperature of vegetation was same as air temperature and that of membrane was $5^{\circ}C$ higher than air temperature. Vegetation transpiration is considered as the causing factor which make those differences. 3) Results from this study could be used as fundamental data for reducing heat island phenomena and continuos research on this subject would be needed.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.927-935
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• 2021

This study conducted a study to improve the problems of the existing fire sensor system. In the case of the existing system, it took more than 3 minutes to detect a fire even at a short distance, making it difficult to extinguish the initial fire. In order to improve these problems, in this study, a fire detection system using an infrared thermal imaging camera was studied. The infrared image-based fire detection system is relatively wide and can detect fire over a long distance, so it has the advantage of being applicable to many fire detection systems. As a result of conducting a field test using the fire detection system, a fire that occurred about 2 km ahead was detected within about 10 seconds. Since the fire detection function of this system can detect within 10 seconds from a distance of about 2 km, it was applicable to forest fires that occur frequently in spring and autumn.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.7
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• pp.46-52
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• 1995

This paper proposes methodologies for the development of radiation thermometer using InSb photo-detector of which spectral sensitivity is excellent over the wave length range of 2 .mu. m .approx. 5 .mu. m. The proposed radiation thermometer has broad measurement range from normal to high, up to more than 1000 .deg. C, with high accuracy, and can measure temperature on the material surface or heat emission noncontactely with high speed. Optical system was consisted of two convex lens with foruslength of 15.2mm for infrared lay focusing, Ge filter to cut the short wave length components and sapphire filter to cut the long wave length components. The cold shielded was installed in the whole surface of the light-absorbing element to remove the error- mometer, calibration using black body furnace which has temperature range of 90 .deg. C .approx. 1100 .deg. C was carried out, and temperature calaibration curve was obtained by exponential function curvefitting. The result shows maximum error less than 0.24%(640K .+-. 1.6K) over the measurement range of 90 .deg. C .approx. 700 .deg. C, and from this result the usefulness of the developed thermometer has been confirmed.

• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.1
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• pp.22-30
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• 2023

When tracking small UAVs and drone targets in cloud clutter environments, MWIR sensors are often unable to track targets continuously. To overcome this problem, the SWIR sensor is mounted on the same gimbal. Target tracking uses sensor information fusion or selectively applies information from each sensor. In this case, parallax correction using the target distance is often used. However, it is difficult to apply the existing method to small UAVs and drone targets because the laser rangefinder's beam divergence angle is small, making it difficult to measure the distance. We propose a tracking method which needs not parallax correction of sensors. In the method, images from MWIR and SWIR sensors are captured simultaneously and a tracking error for gimbal driving is chosen by effectiveness measure. In order to prove the method, tracking performance was demonstrated for UAVs and drone targets in the real sky background using MWIR and SWIR image sensors.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.45.2-45.2
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• 2019

The main-belt asteroid (5247) Krylov is known as a Non-Principal Axis (NPA) rotator. However, the shape model and spin state of this asteroid were not revealed. The physical model of an asteroid including spin state and shape is regarded to be important to understand its physical properties and dynamical evolution. Thus, in order to reconstruct the physical model of Kryolv, we applied the light curve inversion method using not only the optical light curves observed with ground-based telescopes in three apparitions during 2006, 2016, and 2017, but also the infrared light curves obtained with the Wide-field Infrared Survey Explorer (WISE) in 2010. We found that it is rotating in Short Axis Mode (SAM) with the rotation and precession periods of 368.71 hr and 67.277 hr, respectively. The orientation of the angular momentum vector is (298°, -58°) in the ecliptic coordinate system. The ratio of moments of inertia of the longest axis to the shortest axis is I_a/I_c = 0.36; the ratio of moments of inertia of the intermediate axis to the shortest axis is I_b/I_c = 0.96. Finally, the excitation level of this asteroid is found to be rather low with a ratio of the rotational kinetic energy to the basic spin state energy as E/E₀ ≃ 1.024. We will briefly discuss the possible evolutionary process of Krylov in this presentation.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.5
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• pp.643-648
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• 2005

Near infrared reflectance spectroscopy (NIRS) has become increasingly used as a rapid, accurate method of evaluating some chemical constituents in cereal grains and forages. If samples could be analyzed without drying and grinding, then sample preparation time and costs may be reduced. This study was conducted to develop robust NIRS equations to predict fermentation quality of corn (Zea mays) silage and to select acceptable sample preparation methods for prediction of fermentation products in corn silage by NIRS. Prior to analysis, samples (n = 112) were either oven-dried and ground (OD), frozen in liquid nitrogen and ground (LN) and intact fresh (IF). Samples were scanned from 400 to 2,500 nm with an NIRS 6,500 monochromator. The samples were divided into calibration and validation sets. The spectral data were regressed on a range of dry matter (DM), pH and short chain organic acids using modified multivariate partial least squares (MPLS) analysis that used first and second order derivatives. All chemical analyses were conducted with fresh samples. From these treatments, calibration equations were developed successfully for concentrations of all constituents except butyric acid. Prediction accuracy, represented by standard error of prediction (SEP) and $R^2_{v}$ (variance accounted for in validation set), was slightly better with the LN treatment ($R^2$ 0.75-0.90) than for OD ($R^2$ 0.43-0.81) or IF ($R^2$ 0.62-0.79) treatments. Fermentation characteristics could be successfully predicted by NIRS analysis either with dry or fresh silage. Although statistical results for the OD and IF treatments were the lower than those of LN treatment, intact fresh (IF) treatment may be acceptable when processing is costly or when possible component alterations are expected.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.9
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• pp.1175-1182
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• 2013

The lock-in mode infrared thermography (IRT) technique has been developed to improve the detection capability of defects in materials with high thermal conductivity, and it has been shown to provide better detection capability than conventional active IRT. Therefore, to investigate the application of this technique to nuclear piping components, lock-in mode IRT tests were conducted on pipe specimens containing simulated wall-thinning defects. Phase images of the wall-thinning defects were obtained from the tests, and they were compared with thermal images obtained from conventional active IRT tests. It showed that the ability to size the detected wall-thinning defects in piping components was improved by using lock-in mode IRT. The improvement was especially apparent when detecting short and narrow defects and defects with slanted edges. However, the detection capability for shallow wall-thinning defects did not improve much when using lock-in mode IRT.

• Journal of The Korean Astronomical Society
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• v.29 no.2
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• pp.245-253
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• 1996

We have analyzed infrared (IR) images of Jupiter which was observed at the McDonald Observatory, Texas, U.S.A., during the P/SHoemaker-LEvy 9 (SL9) impact period and about one week after the last impact. The IR images were obtained on the 2.7m telescope using a NICMOS array with filters to isolate the $1.5{\mu}m\;NH_3\; band,\;the\;2.3{\mu}m\;CH_4\;band,\;the\;2.12{\mu}m\;H_2\;S(0)$ pressure-induced absorption, and the continua at $1.58{\mu}m\;and\;2.0{\mu}m$ (short K-band). All images except those with the $1.58{\mu}m$ continuum filter show bright impact sites against the relatively dark Jovian disk near the impact latitude of about $45^{\circ}$ S. This implies that dusts originated from the impacts reflect the solar radiation at high altitudes before absorbed by stratospheric $CH_4,\;NH_3 \;or\;H_2$. The impact sites observed with the $2.3{\mu}m$ filter are conspicuously bright against a very dark background. The morphology of impact sites, G, L, and H at 2.3 and $2.12{\mu}m$ filters shows clearly an asymmetric structure toward the incident direction of the comet fragments, in agreement with the studies of visible impact images obtained with the Hubble Space Telescope. Comparisons of reflectances of G, L, and H sites with simple radiative transfer models suggest that optically thick dust layers were formed at high altitudes at which methane absorption attenuates incoming sunlight only by about $1\%$. The dust layers in these sites seem to form at about the same altitude regardless of the magnitude of the impacts, but they appear to descend gradually after the impacts. The dust layers have optical depths of 2-5, according to the models.