• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.3
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• pp.213-219
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• 1995

The author carried out an experiment to find out the response of Black porgy, Acanthopagrus schlegelii [Bleeker] to the color lights. The experimental tank ($360L{\times}50W{\times}55H$cm) was set up in a dark room. Six longitudinal sections with 60cm intervals are marked in the tank to observe the location of the fish. Water depth in the tank was kept 50cm level. Light bulbs of 20 W at the both ends of the tank projected the light horizontally into the tank. Two different colored filters were selected from four colors of red, blue, yellow, and white, and they were placed in front of the light bulbs to make different colors of light. Light intensity was controlled by use of auxiliary filters intercepted between the bulb and the filter. The fishes were acclimatized in the dark for 50 minutes before they were employed in the experiment. Upon turning on the light, the number of fish in each section was counted 40 times in 30 second intervals, and the mean of the number of fish in each section was given as the gathering rate of the fish. The colors favourited by the fish was found in order of blue, yellow, white and red in the day-time and blue, red, yellow and white at night. The difference of the average distribution on two different colors of light was 7.18%(0.35-19.55%), and the difference in the daytime(8.20%) was larger than at night (6.15%). The gathering rate of fish on illumination period didn't show the regular trend of increase and decrease, and was fluctuated with instability. The difference of the gathering rate on two different colors of light wasn't distinct, and the difference in the daytime was larger than at night.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.11
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• pp.105-114
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• 2015

This paper proposes methods to remove background area and segment region of interest (ROI) in chest X-ray images. Conventional algorithms to improve detail or contrast of images normally utilize brightness and frequency information. If we apply such algorithms to the entire images, we cannot obtain reliable visual quality due to unnecessary information such as background area. So, we propose two effective algorithms to remove background and segment ROI from the input X-ray images. First, the background removal algorithm analyzes the histogram distribution of the input X-ray image. Next, the initial background is estimated by a proper thresholding on histogram domain, and it is removed. Finally, the body contour or background area is refined by using a popular guided filter. On the other hand, the ROI, i.e., lung segmentation algorithm first determines an initial bounding box using the lung's inherent location information. Next, the main intensity value of the lung is computed by vertical cumulative sum within the initial bounding box. Then, probable outliers are removed by using a specific labeling and the pre-determined background information. Finally, a bounding box including lung is obtained. Simulation results show that the proposed background removal and ROI segmentation algorithms outperform the previous works.

• Economic and Environmental Geology
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• v.52 no.5
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• pp.485-497
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• 2019

The Jade Investiture Books in Joseon Dynasty shows diverse facies with various petrographic characteristics to green and white based on color. In lithologically, the green rocks are jade composed of calcite and serpentine, and the white ones are marbles consisting mainly in crystalline calcite. As a result of X-ray diffraction of jade rocks, the more green in color, the more increased intensity of serpentine appears. Therefore, the grade of jade is correlated with contents of serpentine. The Jade Investiture Books owned by the National Palace Museum of Korea are subdivided with 104 (41.3%) books made by only jade rocks, 98 (38.9%) books made by only marbles, and 50 (19.8%) books mixed with jade rocks and marbles. Among the mixed ones, 47 (18.6%) books consisted mainly of the marbles. This result shows the superior marble books occupy more than half of the total books. The Jade Investiture Books made in early Joseon Dynasty are composed of high grade jade. However, the grade of jade had decreased as the kings changed in process of time, and the composition of marble had increased in reverse proportion of jade. The quality of letter pigments, metal accessories and fabrics also had decreased with jade. These trends are reflected in the aspect of society such as weakening royal authority, national power and finance with the course of time. The jade of the books has different mineralogical characteristics from some modern jade produced in Chuncheon nephrite and Buyeo precious serpentine in Korea. Meanwhile, there is ancient literature that described quarries from Namyang in Hwaseong of Gyeonggi province. This area has a wide distribution of gneiss, limestone and limesilicate rocks are interbedded between muscovite schist. The limesilicate rocks contain diopside, which produced serpentine through alteration. It has possibility to make the Jade Investiture Books using these small amounts of jade through mining activity.

• The Journal of Engineering Geology
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• v.29 no.3
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• pp.265-277
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• 2019

Changes in the amount, intensity, frequency, and type of precipitation, in conjunction with global warming and climate change, critically impact groundwater recharge and associated groundwater level fluctuations. Monthly gravity levels by the Gravity Recovery and Climate Experiment (GRACE) are acquired to monitor total water storage changes at regional and global scales. However, there are inherent difficulties in quantitatively relating the GRACE observations to groundwater level data due to the difficulties in spatially representing groundwater levels. Here three local interpolation methods (kriging, inverse distance weighted, and natural neighbor) were implemented to estimate the areal distribution of groundwater recharge changes in South Korea during the 2002-2016 period. The interpolated monthly groundwater recharge changes are compared with the GRACE-derived groundwater storage changes. There is a weak decrease in the groundwater recharge changes over time in both the GRACE observations and groundwater measurements, with the rate of groundwater recharge change exhibiting mean and median values of -0.01 and -0.02 cm/month, respectively.

• Journal of the Korean Society of Radiology
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• v.13 no.2
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• pp.253-260
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• 2019

Radiation dose enhancement is a method of increasing the cross section of interaction, thus increasing the deposited dose. This can contribute to linear energy transfer, LET and relative biological effectiveness, RBE. Previous studies on dose enhancement have been mainly focused on X, ${\gamma}-rays$, but in this study, the dose enhancement was analyzed for proton using Monte Carlo simulation using MCNP6. Based on the mathematical modeling method, energy spectrum and relative intensity of spread out Bragg-peak were calculated, and evaluated dose enhancement factor and dose distribution of dose enhancement material, such as aurum and gadolinium. Dose enhancement factor of 1.085-1.120 folds in aurum, 1.047-1.091 folds in gadolinium was shown. In addition, it showed a decrease of 95% modulation range and practical range. This may lead to an uncertain dose in the tumor tissue as well as dose enhancement. Therefore, it is necessary to make appropriate corrections for spread out Bragg-peak and practical range from mass stopping power. It is expected that Monte Carlo simulation for dose enhancement will be used as basic data for in-vivo and in-vitro experiments.

• Korean Journal of Optics and Photonics
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• v.29 no.6
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• pp.275-284
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• 2018

In this study we propose a hybrid color-filter design method in which a nanohole array and a nanodisk array are separated by nanopillars of the material AZ 1500. We propose a design method for an RGB color filter, using the tendency of transmitted light according to each design variable. Especially we analyzed the intensity distribution of the electric field in the cross section, and set the height of the nanopillars so that the local surface-plasmon resonances generated in the two different arrays do not affect each other. The optical characteristics of the optimized color filter are as follows: In the case of the red filter, the ratio of the wavelength band expressing red in the visible broadband is 55.01%, and the maximum transmittance is 41.53%. In the case of the green filter, the ratio of the wavelength band expressing green is 40.20%, and the maximum transmittance is 42.41%. In the case of the blue filter, the ratio of the wavelength band expressing blue is 32.78%, and the maximum transmittance is 30.27%. We expect to improve the characteristics of color filters integrated in industrial devices by this study.

• Ecology and Resilient Infrastructure
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• v.8 no.1
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• pp.1-8
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• 2021

A surface image velocimeter (SIV) measures the velocity of a particle group by calculating the intensity distribution of the particle group in two consecutive images of the water surface using a cross-correlation method. Therefore, to increase the accuracy of the flow velocity calculated by a SIV, it is important to accurately calculate the displacement of the particle group in the images. In other words, the change in the physical distance of the particle group in the two images to be analyzed must be accurately calculated. In the image of an actual river taken using a camera, camera lens distortion inevitably occurs, which affects the displacement calculation in the image. In this study, we analyzed the effect of camera lens distortion on the displacement calculation using a dense and uniformly spaced grid board. The results showed that the camera lens distortion gradually increased in the radial direction from the center of the image. The displacement calculation error reached 8.10% at the outer edge of the image and was within 5% at the center of the image. In the future, camera lens distortion correction can be applied to improve the accuracy of river surface flow rate measurements.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.1
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• pp.35-44
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• 2022

The V_S30 map is used as a key variable for site amplification in the ShakeMap, which predicts ground motion at any site. However, no V_S30 map considering Korean geology and geomorphology has been developed yet. To develop a proxy-based V_S30 map, we used 1,101 V_S profiles obtained from a geophysical survey and collected proxy layers of geological and topographical information for the Korean Peninsula. Then, V_S30 prediction models were developed using linear regression analysis for each geological age considering the distribution of V_S30. As a result, models depending on geomorphology were suggested per each geologic group, including Quaternary, Fill, Ocean, Mesozoic group and Precambrian. Resolution of map is doubled from that of V_S30 map by U.S. Geological Survey (USGS). Standard deviation of residual in natural log of proxy-based V_S30 map is 0.233, whereas standard deviation of slope-based USGS V_S30 map is 0.387. Therefore, the proxy-based V_S30 map developed in this study is expected to have less uncertainty and to contribute to predicting more accurately the ground motion amplitude.

• Korean Chemical Engineering Research
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• v.60 no.4
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• pp.564-573
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• 2022

Calcium carbonate (CaCO₃) exhibits three polymorphs: calcite with arhombohedral, vaterite with a spherical, and aragonite with a needle-like structure. Qualitative and quantitative analyses of the morphology of CaCO₃ are very important to investigate the synthesis of single-crystal vaterite and aragonite. In this work, the polymorphs of calcium carbonate were quantitatively analyzed using XRD. Pure vaterite and pure aragonite were synthesized and the peak distribution of a single phase was analyzed. The vaterite fraction of a mixture of calcite and vaterite was calculated based on the intensity of a specific diffraction peak, and compared to the results based on the peak area. The mean value of f_sV (the correction factor for the peak area of vaterite) was 0.654. The phase analysis of calcite-aragonite mixtures was performed, and the mean value of f_sA (the correction factor for the peak area of aragonite) was obtained as 0.6713. Using these factors, Eq. (24)~Eq. (32) for the quantitative analysis based on the total peak area of XRD were derived to calculate the phase contents of ternary phase CaCO₃. And three-component XRD section was defined considering overlapping sections.

• Parasites, Hosts and Diseases
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• v.59 no.6
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• pp.625-634
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• 2021

Based on the field investigations in 91 investigation sites (counties) in southwest China between 2001 and 2019, the present paper reported the chigger mites on A. agrarius mice in southwest China for the first time by using a series of statistical methods. From 715 striped field mice captured in 28 of 91 investigated sites, only 255 chiggers were collected, and they were identified as 14 species, 6 genera in 3 subfamilies under 2 families. Of 715 A. agrarius mice, only 24 of them were infested with chigger mites with low overall prevalence (P_M=3.4%), overall mean abundance (M_A=0.36 mites/host) and overall mean intensity (M_I=10.63 mites/host). The species diversity and infestation of chiggers on A. agrarius were much lower than those previously reported on some other rodents in southwest China. On a certain species of rodent, A. agrarius mouse in southwest China seems to have a very low susceptibility to chigger infestations than in other geographical regions. Of 14 chigger species, there were 3 dominant species, Leptotrombidium sialkotense, L. rupestre and Schoengastiella novoconfuciana, which were of aggregated distribution among different individuals of A. agrarius hosts. L. sialkotense, one of 6 main vectors of scrub typhus in China, was the first dominant on A. agrarius. The species similarity of chigger mites on male and female hosts was low with C_SS=0.25, and this reflects the sex-bias of different genders of A. agrarius mice in harboring different chigger species.