• Journal of Radiation Industry
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• v.9 no.4
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• pp.209-216
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• 2015

It has been about 5 years since the Fukushima nuclear power plant accident, which contaminated large area with radioactive materials. It is necessary to assess radiation dose to establish evacuation areas and to set decontamination goal for the large contaminated area. In this study, we assessed temporal trend of radiation dose to the public living in the large area contaminated with radioactive materials after the Fukushima nuclear power plant accident. The dose assessment was performed based on Chernobyl model and RESRAD model for two evacuation lift areas, Kawauchi and Naraha. It was reported that deposition densities in the areas were $4.3{\sim}96kBq\;m^{-2}$ for $^{134}Cs$, $1.4{\sim}300kBq\;m^{-2}$ for $^{137}Cs$, respectively. Radiation dose to the residents depended on radioactive cesium concentrations in the soil, ranging $0.11{\sim}2.4mSv\;y^{-1}$ at Kawauchi area and $0.69{\sim}1.1mSv\;y^{-1}$ at Naraha area in July 2014. The difference was less than 5% in radiation doses estimated by two different models. Radiation dose decreased with calendar time and the decreasing slope varied depending on dose assessment models. Based on the Chernobyl dosimetry model, radiation doses decreased with calendar time to about 65% level of the radiation dose in 2014 after 1 year, 11% level after 10 years, and 5.6% level after 30 years. RESRAD dosimetry model more slowly decreased radiation dose with time to about 85% level after 1 year, 40% level after 10 years, and 15% level after 30 years. The decrease of radiation dose can be mainly attributed into radioactive decays and environmental transport of the radioactive cesium. Only environmental transports of radioactive cesium without consideration of radioactive decays decreased radiation dose additionally 43% after 1 year, 72% after 3 years, 80% after 10 years, and 83% after 30 years. Radiation doses estimated with cesium concentration in the soil based on Chernobyl dosimetry model were compared with directly measured radiation doses. The estimated doses well agreed with the measurement data. This study results can be applied to radiation dose assessments at the contaminated area for radiation safety assurance or emergency preparedness.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.2 s.109
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• pp.71-82
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• 2005

A large scale of riverside rearrangement has been recently done in the major rivers in Korea. So inundation possibility in agricultural area closed by these rivers has been higher than the possibility a few years ago. However, land use in this area has not been adjusted to a change of this situation near the rivers. Therefore, when typhoon or heavy rain is happened on this area, it can cause a large damage in agricultural area. This study analyzed inundation potentiality in agricultural area at Ibang-myeon, Changnyeong-gun, Kyeongnam-province, Korea by using the logistic regression model and the piecewise regression model. The first thing we did was to transfer the inundation area per elevation to the accumulated inundation area per elevation. This accumulated inundation area per elevation as an distribution function could be described by the logistic regression model(LRM), and piecewise regression model(PRM) could make it much more accurate to analyze the inundation area per elevation. As a result, the regression models derived from LRM and PRM showed $R^2$ over 0.950. The models derived from LRM and PRM in Ibang-myeon noted that frequently inundated area(FIA) was shown up to 12.12m in elevation, and potentially inundated area(PIA) was shown up to 14.60m in elevation. In FIA, regular agricultural activity would be impossible. And It would be not easy to continue the regular agricultural activity in PIA. So, this land should be rearranged to be used for a buffer zone for ecosystem protection, landscape conservation and things like that in riverside.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.5
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• pp.135-145
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• 2010

This study was carried out to investigate the current urban forest network and future plan of forest framework using nearest features program where stepping stones within 5km from the core forest were selected in the program. We found several conclusions as follows: First, we found that cities in inland area including Daegu, Dajeon and Gwangju have quite different types of forest network with comparing to the cities nearby coastline including Busan, Incheon and Ulsan. The cities in inland area have large mountain patch around each city. However they have small and lower number of island forests within their urban area. Otherwise, cities nearby coastline have more forest patches than in the cities in inland area, and Busan and Incheon especially have strong forest network using various size of forest patches. Second, Daegu and Daejeon have much smaller forest patches distributed in each urban area. So additional forest patches should be added to have highly strong forest network within urban area. Third, Ulsan and Gwangju have most stepping-stone forests close to the large mountain patches in suburban area, which are not able to connect to the forest patches in the central area of each city So additional forest patches are needed to be added in the central area of each city for reinforcing the effect of stepping stone in the central area. Though there should be an addition approach except for forest size and its isolation to construct the ecological network in an urban area, this indices can be a good method to check an environmental and ecological status in an urban area.

• Journal of the Korea Construction Safety Engineering Association
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• s.43
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• pp.98-106
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• 2007

In this paper, a ground disturbance effects, strength and consolidation characteristics of soft clay through using the large block samples($\theta$:300mm, H:400mm) and the piston samples, f hose which had been gathered in west coast and south coast. Especially, we have assessed the coefficient of horizontal consolidation when penetrating the mandrel considering the variance of ratio between diameter and height in drainage sample through the experiment of the oedometer test and Rowecell and also investigated the disturbance area in smear zone by interior model test, the strength originated by disturbance, the variance in characteristics of the consolidation. As the result, the large block sample has been investigated that ihe uniaxial compression test(qu) was shown bigger than the piston sample by about 11-19%. Under the size of anistropy in consolidation, the coefficient ratio of consolidation(ch/cv,) perfomed by standard consolidation test(SC) was shown bigger than that of (Cro/Cv) by the Rowecell test. And the coefficient ratio of consolidation(Cro/Cv) perfomed by piston sample was evaluated bigger than that Of (Cro/Cv) by the large block sample by about 0.9-1.9. The coefficient ratio of consolidation along with the variance in ratio of between diameter and height when penetrating the mandrel was shown big difference according to the characteristics of soil of the specimen. In addition, ds/dw of smear zone at the marine clay in west-south was ranged from 1.6 to 4.2. The width of variance in rat io[(qud)/(quud)] of strength n the area between disturbance and undisturbance was shown big as about 72-91% but the principle was judged with the similiar range when the decrease of the strength in smear zone become the zone under 25% in unditurbance area.

• Journal of Ocean Engineering and Technology
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• v.35 no.6
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• pp.446-456
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• 2021

To build an environment facility of a large-scale ocean basin, various detailed reviews are required, but it is difficult to find data that introduces the related research or construction processes on the environment facility. The current generator facility for offshore structure safety evaluation tests should be implemented by rotating the water of the basin. However, when the water in the large basin rotates, relatively large flow irregularities may occur and the uniformity may not be adequate. In this paper, design and review were conducted to satisfy the performance goals of the DOEB through computational numerical analysis on the shape of the waterway and the flow straightening devices to form the current in the large tank. Based on this, the head loss, which decreases the flow rate when the large tank water rotates through the water channel, was estimated and used as the pump capacity (impeller) design data. The impeller of the DOEB current generator was designed through computational numerical analysis (CFD) based on the lift surface theory from the axial-type impeller shape for satisfying the head loss of the waterway and maximum current velocity. In order to confirm the performance of the designed impeller system, the flow rate and flow velocity performance were checked through factory test operation. And, after installing DOEB, the current flow rate and velocity performance were reviewed compare with the original design target values. Finally, by measuring the current velocity of the test area in DOEB formed through the current generator, the spatial current distribution characteristics in the test area were analyzed. Through the analysis of the current distribution characteristics of the DOEB test area, it was confirmed that the realization of the maximum current velocity and the average flow velocity distribution, the main performance goals in the waterway design process, were satisfied.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.8 no.3
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• pp.246-255
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• 1996

A mild slope equation of parabolic type is derived with the revision of the 2nd order differential term and a new approach for the application to large area is presented. The replacement with long waves can overcome the numerical difficulty due to small waves over the system of large grid sizes. No matter how long the replaced wave length is, the refraction and shoaling are maintained by toeing its own wave speed and group velocity, respectively. However, the diffraction effect is modified by means of Eikonal equation. The developed numerical model was applied to the shoal of Ito and Tanimoto (1972) to yield the satisfactory results.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2001.10a
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• pp.319-321
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• 2001

In general, it is difficult to control weeds, diseases and insects with no chemical material in large scaled cultivation. Particularly, it is nearly impossible for a temperate country with a lot of rain such as Japan or Korea, to make organic agriculture on a large scale. Are there any possibilities to develop a large scaled organic agriculture in the world\ulcorner In Xinjang where is located in the central Asia, established Shihezi Agricultural and Environmental Institute for Arid Area of Central Asia three years ago in Shihezi, Xinjiang, China, for improving crop production in arid area. One of the main objectives is to establish organic agriculture in Xinjiang, with using suitable conditions for agriculture.

• The Journal of Information Systems
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• v.20 no.3
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• pp.111-127
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• 2011

This study is intended for international cooperation in the field of LED were analyzed. The results, LED wide coverage areas, and a promising future is expected to grow fast enough to occupancy for a major national technology is a competitive situation. Chip Scale Package, including our country, such as LED manufacturing technology that might be competitive in parts, but new technologies such as renal substrate R&D and technology development still active preemption is not the situation. Renal substrate, particularly, large-diameter sapphire, large size/large LED manufacturers, such as a promising area for future research and development support will be needed. To do this, previous research in this area and the U.S., Japan cooperation in such studies also will need to expand. Bibliometrics way through this study, analytical techniques and analytical tools used in the integrated analysis of the usefulness and necessity of the system development were found.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.145-148
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• 2001

A large area plasma source using parallel $2{\times}2$ ICP antennas showed improved etching uniformity by the E-ICP operation. ITO etching process with $CH_4$ gas chemistry is optimized with the DOE (Design of Experiment) based on Taguchi method. Various methane ratios in methane and argon mixture are compared to confirm the effect of polymerization. The analysis shows that the effect of bias power is the largeset. We obtained higher ITO etching rate and better uniformity on $350{\times}300mm$ substrate at the 50Hz magnetization frequency of the E-ICP operation technique,

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.145-148
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• 2001

A large area plasma source using parallel 2x2 ICP antennas showed improved etching uniformity by the E-ICP operation. ITO etching process with CH$_4$ gas chemistry is optimized with the DOE(Design of Experiment) based on Taguchi method. Various methane ratios in methane and argon mixture are compared to confirm the effect of polymerization. The analysis shows that the effect of bias power is the largeset. We obtained higher ITO etching rate and better uniformity on 350x300mm substrate at the 50Hz magnetization frequency of the E-ICP operation technique.