• The Journal of Engineering Geology
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• v.28 no.3
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• pp.489-499
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• 2018

A flume experiments was used to study the characteristics of the surface displacements and volumetric water contents (VWC) during torrential rain. The surface displacement and VWC of the granite weathered soil were measured for rainfall intensity (100, 200 mm/hr) and initial ground condition (VWC 7, 14, 26%). The test processes were also recorded by video cameras. According to the test results, The shallow failure is classified into three types: retrogressive failure, progressive failure and defined failure. In the case of retrogressive failure and progressive failure, relatively large damage could occur due to the feature that soil is deposited to the bottom of the slope. the shallow failure occurred when the VWC reached a certain value regardless of the initial soil condition. It was found that the shallow failure can be predicted through the increase patton of the VWC under the condition of the ground dry condition (VWC 7%) and the natural condition (VWC 14%). For high rainfall intensity, progressive failure predominated, and rainfall intensity above a certain level did not affect wetting front transition.

• Ocean and Polar Research
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• v.27 no.1
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• pp.15-24
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• 2005

In order to investigate the structures and dynamics of phytoplankton communities, each physicochemical environmental factor, species composition, standing crop, and dominant species were examined in the marine ranching ground of Tongyeong coastal waters from April to October, 2000. During the studies, mean water temperature and salinity were $18.8^{\circ}C$ and 33.1 psu, respectively. DO, SS and transparency varied from 5.43 to 11.39 mg/l, 14.6 to 32.4mg/l and 3.5 to 9.0m, respectively. Light intensities varied from 0.02 to $966{\mu}E/m^2/s$, which decreased with depth. $NH_4-N,\;NO_3-N,\;NO_2-N,\;PO_4-P,\;and\;SiO_2-Si$ were fluctuated from 0.059 to 0.332 mg/l, 0.040 to 0.800 mg/l, 0.001 to 0.468 mg/l, 2.3 to $143.0{\mu}g/l$, and 0.007 to 0.600 mg/l, respectively. chlorophyll a concentrations were fluctuated from 0.7 to $8.9{\mu}g/l$. Among 130 taxa of phytoplankton communities observed. diatoms occupied more than 81.54% of the total species, and the others were dinoflagellates and silicoflagellates. Phytoplankton standing crops ranged from $4.6{\times}10^4\;to\;2.6{\times}10^6cells/l$. In October, the standing crops were at bloom level showing more than $10^6cells/lat$ all stations. Dominant species changed by month and station. Leptocylindrus danicus occupied 59.84% in April and 22.03% in June. Pseudo-nitzschia pungens in August and Chaetoceros socialis and Skeletonema costatum in October were predominant species. In order to investigate factors influencing the total phytoplankton standing crops the correlations between the standing crops of diatoms, dinoflagellates, all phytoplanktons occurred and environmental factors were calculated using a multiple regression analysis. The coefficient of determination $(R^2)$ for total standing crops was 0.63 which explained 63% of variance and that of $R^2$ for diatom was 0.82. In statistical analysis, the results showed that the environmental factors influencing the size of the communities were predominantly water temperature, salinity and silicate.

• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.325-335
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• 2020

Forest canopy height can be used for estimate of above-ground forest biomass (AGB) by means of the allometric equation. The remote locations and harsh conditions of mangrove forests limit the number of field inventory data stations needed for large-scale modeling of carbon and biomass dynamics. Although active and passive spaceborne sensors have proven successful in mapping mangroves globally, the sensors generally have coarse spatial resolution and overlook small-scale features. Here we generate a 12 m spatial resolution mangrove canopy height map from TanDEM-X data acquired over the world largest intact mangrove forest located in the Sundarbans. With single-pol. TanDEM-X data from 2011 to 2013, the proposed technique makes use of the fact that the double-bounce scattering that occurs between the water and mangrove trees yields water surface level elevation over mangrove forest areas, thus allowing us to estimate forest height with the assumption of an underlying flat topography. Our observations have led to a large-scale mangrove canopy height map over the entire Sundarbans region at a 12 m spatial resolution. Our canopy height estimates were validated with ground measurements acquired in 2015, a correlation coefficient of 0.83 and a RMSE of 0.84 m. With globally available TanDEM-X data, the technique described here will potentially provide accurate global maps of mangrove canopy height at 12 m spatial resolution and provide crucial information for understanding biomass and carbon dynamics in the mangrove ecosystems.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.6
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• pp.31-43
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• 2014

Confined and mechanically ventilated broiler house has been recently come into wide use to increase productivity and control rearing conditions. However, high dust concentration inside facility can threaten respiratory welfare of farmers and broilers. In Korea, there is no regulation in terms of air quality control inside agricultural facilities and sufficient data is not available. To cope with these, periodic monitoring of inhalable and respirable dust concentration were conducted according to season, broiler's activity and specific events such as shipment work for broilers in mechanically ventilated broiler house. Chamber experiment was also designed to analyze mechanism of dust generation from ground beds according to water contents and surrounding wind environment. Results showed that significant increase of inhalable (p=0.002) and respirable (p=0.03) dust were observed when activity of broilers was high according to entrance of the workers. Even shipment work for matured broilers, high level of dust were observed; inhalable dust was exceeded the threshold limit over maximum 303 % and respirable dust was over maximum 1,550 %, implying that acute respiratory symptoms could be manifested for the workers. From the chamber experiment, critical water contents for interrupting of dust generation were measured; about 45 % for inhalable dust and about 50 % for respirable dust. These results can be a trigger for designing plan of dust control however it still needs consideration of various environmental conditions, hygiene problems, etc.

• Economic and Environmental Geology
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• v.29 no.2
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• pp.215-225
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• 1996

All the radionuclides in high-level nuclear waste will decay to harmless levels eventually but for some radionuclides decay is so slow that their radiation remains dangerous for times on the order of tens or hundreds of thousands of years. At the present time, the most favorite disposal plan for high-level radioactive waste is a mined geological disposal in which canister enclosing stable solid form of radioactive waste is placed in mined cavities locating hundred meters below the surface. The chief hazard in such disposal is dissolution of radionuclides from the waste in the groundwater that will eventually carry the dissolved radionuclides to surface environments. The hazard from possible escape of the radionuclides through groundwater can be delayed by engineered and geologic barriers. The engineered barriers can become useless by unexpected geologic catastrophe such as volcanism, earthquake, and tectonic movement and by fraudulent work such as careless construction, improperly welded canisters within the first few decades or centuries. As a result, dangerously radioactive waste which is still intensively radioactive is directly exposed to attack by moving groundwater. All the more, it is almost impossible to control repositories for times more than 10,000 years. Therefore, naturally controlled geologic, barriers whose properties will not be changed within 10,000 years are important to guarantee the safety of repositories of high-level radioactive waste. In Sweden and France, the suitability of granite for the mined geological disposal of high-level waste has been studied intensively. According to the research in Sweden and France, granites has the following physio-chemical characteristics which can delay the transportation of radionuclide by groundwater. First, the permeabilities of granites decreases as the depth increases and is $10^{-8}{\sim}10^{-12}m/s$ at depth below 300 m. Second, groundwater at depth below 300 m has pH=7-9 and reducing condition (Eh=-0.1~0.4). This geochemical condition is desirable to prevent both canister and solid waste from corrosion. Third most radionuclides are not transported by low solubilities and some radionuclide with high solubility such as Cs and Sr are retarded by absorption of geologic media through which ground water flows. Therefore, if high-level waste is disposed at depth below 300 m in the granite body which has a low permeability and is geologically stable more than 10,000 years, the safety of repositories from the hazard due to radionuclide escape can guaranteed for more than 10,000 years.

• Journal of the Korea Concrete Institute
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• v.27 no.5
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• pp.559-568
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• 2015

In this study, multi-component blended concrete mix with fly ash and ground granulated blast furnace slag according to 3 level of type of warter reduction agent (type of 0%, 8% and 16%) and 3 level of water-binder ratio (40%, 45% and 50%) was prepared for evaluation of effect of physical characteristics of concrete using multi-component blended binder according to warter reduction efficiency of warter reduction agent. In addition, concrete mix was carried out repetition test of three times in order to secure the reliability. As a result, compressive strength according to type of warter reduction agent was found that difference of strength was about 20% occurred, warter reduction efficiency of warter reduction agent was showed that a great influence on qualities of concrete. Therefore, reflected the effect of warter reduction efficiency of warter reduction agent, prediction model equations of compressive strength for multi-component blended concrete was proposed, it was found that more than 90% of the high correlation.

• Journal of Environmental Science International
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• v.15 no.4
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• pp.311-317
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• 2006

The purpose of this study was to investigate Rn concentration and annual radiation exposure level in the basement and first floor. The Rn Cup monitors were placed in different environments such as shopping stage, office building, Apartment, Hospital, house in Seoul from Match 1996 to April 1997 and CR-39 films were collected every two months. The mean radon concentration in the basement of house($88.6\;Bq/m^3$) showed the highest level among the areas, while radon concentration on the first floor of house($50.5\;Bq/m^3$) showed the higher than other areas. The annual radiation exposure dose that person on the floor / in the basement of differential place in the seoul can be exposed during living was estimated from 24.11 to 87.64 mRem/yr. This radiation dose is significantly lower than 130mRem maximum radiation dosage from the radon nuclide prescribed by the ICRP, with respect to the overall average exposure of the working adult. this study indicated that possible radon sources on the first floor / in the basement areas are radon intrusion from soil gas, construction materials, or ground water leaking. Further study is needed to quantitatively assess major contributions of radon-222 and health effect to radon exposure.

• Journal of Environmental Science International
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• v.18 no.9
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• pp.1011-1015
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• 2009

The vegetated porous pavement can be installed as an alternative way to replace the traditional pavement, which contributes less to the water circulation system in the urban area. This study aims to an investigation based on the shadow and pressure of the vehicle system, where the turfgrass get grown and the green block get constructed on the grassy parking lot. This study might achieve these conclusions, in the case of use 'green block' makes grass parking lot, plant a kind of 'zenith' and takes sod thickness 40 mm are more efficient for turfgrass growth in the early times. In the case of parking over 8 hours in a day, after 5 weeks turfgrass growth would come into reduce. So over 4 hours parking and after 9 weeks, we need consider to setting up green block in grassy parking lot. The grassy ground would get pressured by the vehicles' load and it would bring into some damage due to the load after 3 weeks. So we should put the grass's growth root point under the designed a top of 'green block' level. When the vehicle amounts and parking density is in a low level, it could be an environmentally friendly product.

• Journal of Korean Elementary Science Education
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• v.29 no.4
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• pp.441-450
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• 2010

The purpose of this study was to evaluate the level of elementary gifted students' argumentation and examine the special features of argumentation founded in scientific inquiry. 28 students were selected in the special education center for the gifted in K National University. They were organized 8 groups of 3~4 students and engaged in scientific inquiry activity. The researcher wasn't involved in students' inquiry activity and argumentation except for the guiding and introducing their activity. In the first session, each group carried out the experiment 'Putting a heated can in the water' and then, the students discussed to probe their experimental results and build their explanation. In the second session, each group presented their experiment results and evidence from their experiment justifying their claims, and had questions from other groups. The protocol data during 8 groups' argumentations were analyzed using 'Rubric for Scientific Argumentation Assessment' (Yang et al., 2009) in three domains- the form, content and attitude. As a result, in form domain, almost groups were rated 2 points due to their argument without rebuttal on the subcategory of 'composition', but they got a good grade above 3 points in subcategory such as 'claim', 'ground', and 'conclusion'. In content domain, almost groups got points above 3 points. In attitude domain, there were some striking contrast between each groups. Six groups got good score more than 4 points on the subcategory of openness, but two groups, they alleged and got score below 3 point. While the 6 groups of all got 4 points in the aspect of participation, 3 groups got 3 points lower than because they only just asserted and not interact with other groups. Throughout the argumentation, two features were found that; as time goes by, arguments were refined; Students tended to use their prior to knowledge rather than evidence such as experimental data in making claims and conclusions.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.702-706
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• 1996

Husked barley contained 17.2% dietary fiber and naked barley contained 14.9% dietary fiber. The barley was ground in a Udy cyclotec mill having a 0.5 mm screen and sieved with a 400-mesh screen (38 m openings). Coarse material of naked barley retained by the screen, with a weight yield of 54.1%, contained 7.0% soluble dietary fiber, 13.9% insoluble dietary filer and 20.9% total dietray fiber. As the naked barley flour level increased in bread baking, the water absorption, mixing time, and loaf weight increased, but the loaf volume decreased. Barley flour was added to wheat flour at a replacement level of 10% without a large adverse effect on bread quality, and the dietary fiber content of bread was increased from 3.0% to 5.0%. The soluble dietary fiber content was not changed, but the insoluble dietary fiber content was increased during the baking process.