• Journal of Astronomy and Space Sciences
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• v.29 no.4
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• pp.407-411
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• 2012

Space-borne remote sensing is an effective and inexpensive way to identify crop fields and detect the crop condition. We examined the multi-temporal spectral characteristics of rice fields in South Korea to detect their phenological development and condition. These rice fields are compact, small-scale parcels of land. For the analysis, moderate resolution imaging spectroradiometer (MODIS) and RapidEye images acquired in 2011 were used. The annual spectral tendencies of different crop types could be detected using MODIS data because of its high temporal resolution, despite its relatively low spatial resolution. A comparison between MODIS and RapidEye showed that the spectral characteristics changed with the spatial resolution. The vegetation index (VI) derived from MODIS revealed more moderate values among different land-cover types than the index derived from RapidEye. Additionally, an analysis of various VIs using RapidEye satellite data showed that the VI adopting the red edge band reflected crop conditions better than the traditionally used normalized difference VI.

• Korean Journal of Remote Sensing
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• v.34 no.1
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• pp.141-150
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• 2018

Crop type classification is essential for supporting agricultural decisions and resource monitoring. Remote sensing techniques, especially using hyperspectral imagery, have been effective in agricultural applications. Hyperspectral imagery acquires contiguous and narrow spectral bands in a wide range. However, large dimensionality results in unreliable estimates of classifiers and high computational burdens. Therefore, reducing the dimensionality of hyperspectral imagery is necessary. In this study, the Random Forest (RF) classifier was utilized for dimensionality reduction as well as classification purpose. RF is an ensemble-learning algorithm created based on the Classification and Regression Tree (CART), which has gained attention due to its high classification accuracy and fast processing speed. The RF performance for crop classification with airborne hyperspectral imagery was assessed. The study area was the cultivated area in Chogye-myeon, Habcheon-gun, Gyeongsangnam-do, South Korea, where the main crops are garlic, onion, and wheat. Parameter optimization was conducted to maximize the classification accuracy. Then, the dimensionality reduction was conducted based on RF variable importance. The result shows that using the selected bands presents an excellent classification accuracy without using whole datasets. Moreover, a majority of selected bands are concentrated on visible (VIS) region, especially region related to chlorophyll content. Therefore, it can be inferred that the phenological status after the mature stage influences red-edge spectral reflectance.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.22 no.2
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• pp.52-69
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• 1996

Nano-Sized TiO$_2$ particles with diameter between 2 and 5 nm are synthesized in Water/Triton X-100/n-Hexane microemulsion. Particles show the amorphous structure and partially hydroxide form. The optical absorbance of particles appears at 250nm and band edge at 340nm. Gold metal is deposited on the surface of TiO$_2$ particles by reduction reaction of Au(III) ion with sodium hypophosphite. The size of gold-deposited particles is 20nm, and the optical absorbance appears at 270nm and at 550nm. So particles show the red color. The dense precipitation is formed by aggregation in the TiO$_2$ nano-sized particles of about 5nm size. But the bulky precipitation is formed by agglomeration phenomena in the gold-deposited particles of 20nm size. And also gold-deposited particles is easily dispersed by being re-dispersed in PEG/Water solution. This study has compared those things measuring the SPF characteristics of the cosmetics made of the synthesized particles. If the particle size is controlled appropriately, then the SPF value will be higher, or more colorless cosmetics will be made.

• Journal of the Korean Ceramic Society
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• v.53 no.6
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• pp.665-669
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• 2016

$TiO_2/BiVO_4$ layered films were prepared by sol-gel and spin coating methods. X-ray diffraction (XRD), scanning electron microscopy (SEM) and Uv-vis spectroscopy were used to investigate the crystal structure, morphology and ultraviolet-visible absorption of the $TiO_2/BiVO_4$ films. The photocatalytic activity of the prepared films was inspected according to the degradation of methylene blue. The results show that the prepared films present a net chain structure; the absorption band edge had obvious red shift. The degradation of the methylene blue solution was about 80% after 300 mins using $TiO_2/BiVO_4$ layered films under visible light, which was stronger than when using only pure $TiO_2$ film and $BiVO_4$ film.

• Journal of Ginseng Research
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• v.4 no.1
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• pp.49-54
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• 1980

This investigation were carrion out to know the frequency, size and distribution of stomata in Korean ginseng, acanthopanax and codonopsis. The results are as follows; 1. Stomatal frequency in ginseng leaf was remarkably less than those of acanthopanax and codonopsis leaf, but size of stomata in ginseng leaf was larger than those of acanthopanax and codonopsis leaf. 2. Stomatal frequency of one year old ginseng plant was higher than those of the older. Two to five years old ginseng plants were not differed in frequency and size of stomata. 3. Frequency and size of stomata were higher and larger in red-berry variant in compare to yellow-berry variant. 4. Stomatal frequency in different leaf Position was not significantly different among those of middle leaf, first side leaf and second side leaf, but in decreasing order of middle Part, upper, lower part and edge in the same ginseng leaf. 5. Stomata was not seen in adaxial surface and petiole of leaf ginseng, acanthopanax and codonopsis. 6. Stomatal frequency was higher in ginseng plant grown under no$.$shading compared to shading, and that of ginseng plant in rear line was less than that of front line under the same shade roof.

• Applied Science and Convergence Technology
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• v.23 no.5
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• pp.279-283
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• 2014

Al doped ZnO thin films have been deposited by a RF magnetron sputtering technique from a ZnO (2 wt.% $Al_2O_3$) target onto glass substrates heated at temperature ranging from RT to $400^{\circ}C$. X-ray diffraction analysis shows that the deposits have a preferential growth along the c-axis of a hexagonal structure. The full with at half maximum decreases from 0.45 to $0.43^{\circ}$ in the studied temperature range. The root main square surface roughness increases with substrate temperature from 1.89 to 2.67 nm. All films are transparent up to 80% in the visible wavelength range and the adsorption edge is red-shifted with substrate temperature from RT to $400^{\circ}C$. The sheet resistance increases from 92 ohm/sq to 419 ohm/sq when the deposition temperature increases from RT to $400^{\circ}C$. The increment of sheet resistance is caused by lowered carrier concentration resulting from an increase in surface roughness.

• Journal of the Korean institute of surface engineering
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• v.47 no.5
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• pp.233-238
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• 2014

In this paper, in order to achieve slim and light liquid crystal display, we examine the optical conditions that can obtain uniform light with higher optical efficiency over whole light guide plate (LGP) through simulation. Furthermore, to overcome the issues of hot spot in front of red, green, and blue light emitting diodes (RGB LEDs) source and non-uniform color mixing, we propose four shaped color mixing bars tied up with the LGP and check the optical characteristics of the LGP with them by simulation. Consequently, we could know the optical conditions of improving optical efficiency and optical uniformity in the LGP through the optical design. Also we confirmed that the issues of the hot spot and non-uniform color mixing in edge type LED could be solved by using the ${\bigwedge}$-shaped window color mixing bar.

• Korean Journal of Remote Sensing
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• v.22 no.3
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• pp.175-182
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• 2006

Because of the phenological variation of vegetation growth in temperate region, it is often difficult to accurately assess the surface conditions of agricultural croplands, grasslands, and disturbed forests by multi-spectral remote sensor data. In particular, the spectral similarity between soil and dry vegetation has been a primary problem to correctly appraise the surface conditions during the non-growing seasons in temperature region. This study analyzes the spectral characteristics of the mixture of dry vegetation and soil. The reflectance spectra were obtained from laboratory spectroradiometer measurement (GER-2600) and from EO-1 Hyperion image data. The reflectance spectra of several samples having different level of dry vegetation fractions show similar pattern from both lab measurement and hyperspectral image. Red-edge near 700nm and shortwave IR near 2,200nm are more sensitive to the fraction of dry vegetation. The use of hyperspectral data would allow us for better separation between bare soils and other surfaces covered by dry vegetation during the leaf-off season.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.3
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• pp.293-302
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• 2023

This study examines and proposes standardization approaches to address the heterogeneous issues of metadata in drone imagery within the agricultural sector. Image metadata comes in various formats depending on different camera manufacturers, with most utilizing EXIF and XMP. The metadata of cameras used in fixed-wing and rotary-wing platforms, along with the metadata requirements in image alignment software, were analyzed for sensors like DJI XT2, MicaSense RedEdge-M, and Sentera Double4K. In the agricultural domain, multispectral imagery is crucial for vegetation analysis, making the provision of such imagery essential. Based on Pix4D SW, a comparative analysis of metadata attributes was performed, and necessary elements were compiled and presented as a proposed standardization (draft) in the form of tag information.

• Research in Plant Disease
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• v.30 no.1
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• pp.82-87
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• 2024

Leatherleaf fern (Rumohra adiantiformis) is an important ornamental plant in Indonesia and global. Green fern leaves with bold dark green color with long shelf-life, attract florists as decoration. Indonesia is one important leatherleaf fern exporters, however currently an outbreak of leaf blight decreased production significantly. Initial symptom was reddish brown spots from edge of leaf, which was gradually followed by dark-brown necrotic lesions causing leaf blight and dried. This is a study to do Koch-Postulate approach and molecular identification, to identify the pathogen of the "new emerging disease" reported. Based on multigene analysis using primers from ITS, β-tub and tef1-α gene markers, the pathogen was identified as Neopestalotiopsis sp. All sequences have been deposited in GenBank with accession number of OR905551 (ITS), OR899817 (ßtubulin) and OR899816 (TEF). This Neopestalotiopsis leaf blight causes an emerging concern in leatherleaf fern in Indonesia and global biosecurity because it infected an export commodity.