• Journal of the Korean GEO-environmental Society
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• v.17 no.7
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• pp.5-13
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• 2016

This research is focused on the seepage behavior of embankment which had the weak zone with big permeability. The distributed TDR (Time Domain Reflectometer) and point sensors such as settlement gauge, pore water pressuremeter, vertical total stressmeter, and FDR (Frequency Domain Reflectometer) sensor were used to measure the seepage characteristics and embankment behavior. Also, the measured data were compared to the data of 2-D and 3-D numerical analysis. The dimension of model embankment was 7 m length, 5 m width and 1.5 m height, which is composed of fine-grained sands and the water level of embankment was 1.3 m height. The seepage behavior of measuring and numerical analysis were very similar, it means that the proper sensing system can monitor the real-time safety of embankment. The result by 2-D and 3-D numerical analysis showed similar saturation processing, however in case of weak zone, the phreatic lines of 2-D showed faster movement than that of 3-D analysis, and finally they converged.

• Journal of Korean Society of Forest Science
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• v.104 no.2
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• pp.239-247
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• 2015

Since 2006, new national forest inventory in Korea has been restructured to assess current status and and monitor the changes in forest resources based on permanent sample plots. The objective of estimate this study is to assess changes in forest resources such as land use/cover categories and forest stand variables. For this study, permanent plot data were collected between 2006-2008 and 2011-2013 in Chungcheongbuk-do, respectively. In order to produce land use/cover change matrix which plays an important role as an activity data for estimating GreenHouse Gas inventory, permanent plots were classified into six land use/cover categories. Additionally, matrixes for assessing the changes in age class and dominant tree species can provide more detailed information. For forest stand variables(tree density, basal area, growing stock, mean diameter at breath height, and mean height), their growth and change were assessed. The periodic annual growth ratios for tree density and basal area were slightly declined whereas that of growing stock was estimated to be about 3.7%. The uncertainty of changes in forest stand variables is less than 5%, except for tree density (RSE: 58%). The variation of tree density is relatively high compared to the other variables.

• Journal of Environmental Science International
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• v.29 no.3
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• pp.209-218
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• 2020

This study was conducted to monitor the growth and development of Abies koreana seedlings in the Hallasan Mountain. Accordingly, the obtained results indicate that the number of A. koreana seedlings increased by 2.6 and 4.8 times in the Yeongsil and Jindallaebat areas, respectively, over the 10-year period. Most of these seedlings were found to be growing on moss-covered rocks. The average tree height over the last 10 years was obtained as 20.4 cm in the Yeongsil area and 3.6 cm in Jindallaebat with growths of 4.1 cm and 1.4 cm, respectively over the last 2 years. Of all the mature trees that were surviving in 2009, 6 died in Yeongsil in 2014 (with an additional 4 in 2018) and 13 in Jindallaebat in 2016. Over the 10-year period, the diameter at breast height of the trees in Yeongsil and Jindallaebat has increased by an average of 0.6 cm and 4.2 cm. Similarly, an average of 6.8 cones was found in the Yeongsil area in 2014 and 26.3 in Jindallaebat in 2016. However, in 2018, no additional cones were found in the former, although an average of 1.4 cones was observed in the latter. With respect to the average temperature and relative humidity, no significant difference could be observed between two monitored areas from 2016 to 2018. However, in July 2017 and February 2018, the average temperature was higher in the Jindallaebat area, while relative humidity was higher in Yeongsil, there by possibly affecting cone growth and flowering between areas. These results indicate the survival and growth of A. koreana seedlings in the Hallasan Mountain is sensitive to the environments of each area. Hence, continuous monitoring of the environment changes and in-depth studies on the flowering and fruiting of A. koreana seedlings needs to be carried out in order to analyze the relationship between their survival rates and changes in weather conditions.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.4
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• pp.204-208
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• 2000

Little information is available for the temporal variation in air temperature profile within rice canopies under development, while much works have been done for a fully developed canopy. Fine wire thermocouples of 0.003 mm diameter (chromel-constantan) were installed at 10 vertical heights by a 10 cm step in a paddy rice field to monitor the air temperatures over and within the developing rice canopy from one month after transplanting (June 29) to just before heading (August 24). According to a preliminary analysis of the data, we found neither the daytime temperature maximum nor the night time minimum at the active radiation surface (the canopy height with maximum leafages) during this period, which is a typical profile of a fully developed canopy. Air temperature within the canopy never exceeded that above the canopy at 1.5 m height during the daytime. Temporal march of the within-canopy profile seemed to be controlled mainly by the ambient temperature above the canopy and the water temperature beneath the canopy, and to some extent by the solar altitude, resulting in alternating isothermal and inversion structures.

• Korean Journal of Applied Biomechanics
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• v.31 no.1
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• pp.72-78
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• 2021

Objective: The purpose of this study was to investigate relations and effectiveness about mountain climbling exercise with different level of support surfaces by analyzing heart rate and EMG data. A total of 10 male college students with no musculoskeltal disorder were recruited for this study. Method: The biomechanical analysis was performed using heart rate monitor (Polar V800, Polar Electro Oy, Finland), step-box, exercise mat, and EMG device (QEMG8, Laxtha Inc. Korea, sampling frequency = 1,024 Hz, gain = 1,000, input impedance > 1012 Ω, CMRR > 100 dB). In this research, step-box were used to create different surface levels on the upper body (flat surface, 10% of subject's height, 20% of subject's height, and 30% of subject's hight). Based on these different conditions, data was collected by performing mountain climbing exercise during 30 seconds. Subjects were given 5 minutes of break to prevent muscular fatigue after each exercise. For each dependent variable, a one-way analysis of variance with repeated measures was conducted to find significant differences and Bonferroni post-hoc test was performed. Results: The results of this study showed that exercise intensity was reduced statistically as increased surface level on the upper body. Muscle activity of the upper rectus abdominis and biceps femoris for 30% of surface level was significantly higher than the corresponding values for flat surface. However, the opposite was found in the rectus femoris. In general, muscle activity of the lower rectus abdominis, erector spinae, external oblique abdominis, and gluteus maximus increased when surface level increased, but the differences were not significant. Conclusion: As a result, the increase in surface level of the body would change muscle activity of the upper body, indicating that different surface level of the upper body may cause significant effect on particular muscles to be more active during mountain climbing exercise. Based on results of this study, it is suggested to set up an appropriate surface level to target particular muscle to expect an effective training. It is also important to set adequate surface levels to create an effective training condition for preventing exercise injuries.

• Journal of Marine Life Science
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• v.3 no.1
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• pp.31-37
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• 2018

We investigated natural habitat of seagrass and created replacement habitat to monitor for restoration of the habitat which is expected to be damaged at Cheonseong harbor in Busan. Depth of water for natural seagrass habitat at Cheonseong harbor was 1.2~3.1 m and the water temperature was 7.4℃, salt concentration was 29.1 psu and pH was 8.05 in January, 2013. The density of seagrass was 167.1±16.4 shoots m^-2, the total length was 48.5±18.1 cm, the height of sheath was 9.1±2.8 cm and the width of leaf was 4.8±1.1 cm, respectively. We transplanted in December 2014 and monitored the habitat during 9 months after transplanted. In the beginning, the density of seagrass was decreased to 8.5 shoots patch^-1 in January and was increased to 19.0 shoots patch^-1 in April. The total height were 73.3±2.9~121.3±6.1 cm, the length of sheath were 9.6±0.6-21.0±1.2 cm, the width of leaf were 5.7±0.1~6.8±0.2 mm. It showed that all values were increased steadily until July and was decreased rapidly in August. Flowering shoot, which was not observed in the beginning of transplanting, started to be spotted in March and was continued to be seen during the monitoring period. We were able to observe seedling of germinated seagrass in seeds in the replacement habitat next year.

• Journal of Astronomy and Space Sciences
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• v.37 no.2
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• pp.143-156
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• 2020

Korea Polar Research Institute (KOPRI) installed an ionospheric sounding radar system called Vertical Incidence Pulsed Ionospheric Radar (VIPIR) at Jang Bogo Station (JBS) in 2015 in order to routinely monitor the state of the ionosphere in the auroral oval and polar cap regions. Since 2017, after two-year test operation, it has been continuously operated to produce various ionospheric parameters. In this article, we will introduce the characteristics of the JBS-VIPIR observations and possible applications of the data for the study on the polar ionosphere. The JBS-VIPIR utilizes a log periodic transmit antenna that transmits 0.5-25 MHz radio waves, and a receiving array of 8 dipole antennas. It is operated in the Dynasonde B-mode pulse scheme and utilizes the 3-D inversion program, called NeXtYZ, for the data acquisition and processing, instead of the conventional 1-D inversion procedure as used in the most of digisonde observations. The JBS-VIPIR outputs include the height profiles of the electron density, ionospheric tilts, and ion drifts with a 2-minute temporal resolution in the bottomside ionosphere. With these observations, possible research applications will be briefly described in combination with other observations for the aurora, the neutral atmosphere and the magnetosphere simultaneously conducted at JBS.

• Journal of the Korean Ceramic Society
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• v.40 no.5
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• pp.481-487
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• 2003

A technique for determination of proportions of char, coal ana coke is needed in order to monitor pulverized coal injection performance in operating blast furnace. Quantitative X-ray powder diffraction analysis can be applied to the problem providing that structural information on carbonaceous materials, coal, char, coke and their mixture are known. Chars were prepared from a coal at different temperatures (1000∼1400$^{\circ}C$) and were characterised by X-Ray powder Diffraction (XRD). The XRD result gave crystallite size (height Lc and diameter, La), aromaticity, number of (002) plane in carbon, and d-spacing. As a result, with increasing heat treat temperature of char, Lc$_{(002)}$, La$_{(10)}$ and number of (002) plane in carbon were increased, and d-spacing and FWHM(Full With Half Maximum) were decreased. Result of prediction of amount of char from the mixtures (char, coke and ore) based on the Lc$_{(002)}$ information of two mixtures (coke and char) showed very close values expected.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.3
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• pp.214-221
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• 2011

This study was performed to develop a video based system which can be used to measure the averaged fish size in a non-intrusive fashion. The design was based on principles of simple stereo geometry, incorporated fish dimensions weight relationships and took into consideration fish movement to lower system costs. As the fish size is an important factor that impacts the economy of an aquaculture enterprise. Size measurements, including fork length, width or height, girth, thickness and mass, can be used to determine fish condition in the fish farm, so the averaged fish size of fish cage needs to consistently monitor in open ocean aquaculture cage. A precision of ${\pm}3%$ for replicate length measurements of a 60cm bar is obtained at distances between 2.0 and 6.0m, and the mean fork length and mean swimming speed of bluefin tuna were estimated to 48.8cm and 0.78FL/s, respectively.

• Korean Journal of Remote Sensing
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• v.30 no.6
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• pp.703-708
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• 2014

$NO_2$ vertical profiles were retrieved via ground based MAX-DOAS measurements for the summer period in 2006 in Beijing, one of the megacities in the Northeast Asia. Large portion of $NO_2$ load was observed at the 0-1 km layer. We found that $NO_2$ rapidly decreases up to the altitude of 3 km. In addition, the retrieved $NO_2$ mixing ratios within 0-1 km layer were compared with those observed at the surface by in-situ monitor. The correlation coefficient (R) between $NO_2$mixing ratios within 0-1 km layer and those at the surface was calculated to be 0.7. The major causes of such discrepancy are thought to be both differences in measured areas and rapid decrease in $NO_2$ mixing ratio with height.