• Korean Journal of Environment and Ecology
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• v.18 no.3
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• pp.306-315
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• 2004

Yangjae stream, stretching through Seocho-gu and Gangnam-gu, is a representative city stream with its environmentally friendly stream makeover project model, launched in 1995. The district of Gangnam-gu, the subject of this study, is under high pressure from the residents for its use as a huge residential areas close to the stream. The study has two main purposes. The first is to identify the condition and characteristic of utilization of Yangjae stream which is currently being increased in use by the stream restoration. Secondly, the study aims to suggest the environment-friendly management to accomplish arrangement of the naturally friendly stream based on the identification survey, The result from the user survey with 303 valid answer sheets show that the people from neighboring residential areas use this stream a lot doing exercising(51.8%) and taking a walk(24.4%) in their free time. Also regular use rate is high, and people are likely to use it alone(30.4%) or as a family(28.4%). With regard to the need of facility increase, even though the respondents required resting places in the shade(80.8%) most, overall, additional introduction of facilities was analyzed as unnecessary(78.8%). safety issue(22.0%) and a lack of convenience facilities(17.6%) and resting places in the shade(16.6%) are pointed as main problems while the users are generally satisfied(59.5%) with the stream. Improving walk-way and planting trees for shade on the slope were designed as a solution for these problems. For securing safety through improvement of walk-way, the scattering of pressure of current walk with building new walk using berms was presented. In order to increase safety on the walk-way(see above figure), the study proposes to build a new walk-way with berms to disperse excessive pressure. It also suggests the tree planting to provide shade in the stream and to make a provision for the planting of forest trees in the current law.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.30-36
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• 2006

Japan's first pilot-scale $CO_2$ sequestration experiment has been conducted in Nagaoka, where 10400 t of $CO_2$ have been injected in an onshore aquifer at a depth of about 1100 m. Among various measurements conducted at the site for monitoring the injected $CO_2$, we conducted time-lapse crosswell seismic tomography between two observation wells to determine the distribution of $CO_2$ in the aquifer by the change of P-wave velocities. This paper reports the results of the crosswell seismic tomography conducted at the site. The crosswell seismic tomography measurements were carried out three times; once before the injection as a baseline survey, and twice during the injection as monitoring surveys. The velocity tomograms resulting from the monitoring surveys were compared to the baseline survey tomogram, and velocity difference tomograms were generated. The velocity difference tomograms showed that velocity had decreased in a part of the aquifer around the injection well, where the injected $CO_2$ was supposed to be distributed. We also found that the area in which velocity had decreased was expanding in the formation up-dip direction, as increasing amounts of $CO_2$ were injected. The maximum velocity reductions observed were 3.0% after 3200 t of $CO_2$ had been injected, and 3.5% after injection of 6200 t of $CO_2$. Although seismic tomography could map the area of velocity decrease due to $CO_2$ injection, we observed some contradictions with the results of time-lapse sonic logging, and with the geological condition of the cap rock. To investigate these contradictions, we conducted numerical experiments simulating the test site. As a result, we found that part of the velocity distribution displayed in the tomograms was affected by artefacts or ghosts caused by the source-receiver geometry for the crosswell tomography in this particular site. The maximum velocity decrease obtained by tomography (3.5%) was much smaller than that observed by sonic logging (more than 20%). The numerical experiment results showed that only 5.5% velocity reduction might be observed, although the model was given a 20% velocity reduction zone. Judging from this result, the actual velocity reduction can be more than 3.5%, the value we obtained from the field data reconstruction. Further studies are needed to obtain more accurate velocity values that are comparable to those obtained by sonic logging.

• Journal of agricultural medicine and community health
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• v.24 no.1
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• pp.145-159
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• 1999

To find the association, between vinyl house work and the prevalence of low back pain, a questionnaire survey was made toward 215 vinyl house farmers and 228 general farmers without vinyl house who are cared by Jungjung Community health Practioners at Soobuk Myun, Damyang-gun, Chollanamdo. 1. Vinyl house farmers were significantly younger in age, higher in educational status higher survival rate of spouse, higher economic state and less cared by medical aid than general farmers. 2. Vinyl house farmers showed shorter career for agricultural work, used modern farming instrument more frequently and worked with sitting position. 3. During unbusy season in general agriculture, vinyl house farmers consumed significantly more time in agricultural work and general activity, but no significant difference of time of the above activity among busy season. 4. During the last spring season when most vinyl house work was performed, vinyl house farmers showed significantly higher prevalence of low back pain than general farmers, but no significant difference of prevalence among the two groups for the last one week. 5. By the simple analysis statistical significant related variables with low back pain was found to be sex(p<0.001), educational status(p<0.05), work posture(p<0.001) and use of modern agricultural machine(p<0.05). 6. By the multiple logistic regression the odds ratio for low back pain among vinyl house farmers were 2.08(95% confidence interval 1.31-3.00) compared to general farmers, the odds ratio among female was 2.35(95% confidence interval 1.24-4.47) to male, the odds ratio among illiterate persons were 2.60(95% confidence interval 1.24-4.47) to high school graduate, and the odds ration among primary school graduate was 2.19(95% confidence interval 1.04-4.47) to high school graduate. In conclusion because vinyl house farmers showed significantly higher rates of low back pain compared to farmers without vinyl house, continuous study to find the true cause of low back pain among vinyl-house farmers and active effort to prevent low back pain are necessary.

• Journal of Radiation Protection and Research
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• v.40 no.3
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• pp.162-167
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• 2015

Although the perfomance indicators of the nuclear power plants in Korea show optimal, it requires detailed analysis and discussion centered on the radiation dose. As analysis methods, analysis on the radiation dose of nuclear power plants over the past five years was assessed by comparing the relevant radiation dose of radiation workers and per capita average annual radiation dose of the world's major nuclear power stations was also analyzed. The radiation workers over the annual radiation dose limit of 50 mSv were not. The contrast ratio of the radiation exposure according to the reactor type was the normal operation of PHWR was 6.2% higher than those of the PWR. This shows the radiation work of PHWR during normal driving operation is much more than those of PWR. According to the Performance Indicators of the World Association of Nuclear Operator, the annual radiation dose per unit in 2013 showed 527 man-mSv of Korea is the best country among the major nuclear power generating states, the world average was 725 man-mSv. The annual per capita radiation dose is about 80% less than 1 mSv of the public dose limit and also the average per capita dose showed a very low level as 0.82 mSv. Workers in related organizations showed 1.07 mSv, the non-destructive inspection agency workers showed 3.87 mSv. The remarkable results were due to radiation reduced program such as development of radiation shielding and radiation protection. In conclusion, the radiation exposured dose of nuclear power plants workers in Korea showed a trend which is ideally reduced. But more are expected to be difficul and the psychological insecurity against the operation of the nuclear power plants is existed to the residents near the nuclear power plants. So the radiation dose reduction policy and radiation dose follow up study of nuclear power plants will be continously excuted.

• Spatial Information Research
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• v.23 no.3
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• pp.11-21
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• 2015

While the number of total population in Seoul has been on the constant decline for the last few years, the number of household has increased due to the rising tendency of the smaller households. In 2010, the small households in the metropolitan areas accounted for 44% of the entire households, and Statistics Korea has reported that one person household, which will take up more than 30% of the whole household, will have been the most common type of household by 2020. This reason of rise will be differently shown according to age like the preferred housing type or surrounding environments, this research is suggest to research hypothesis that distinction of age leads to the spatial distribution of one person household. Therefore, this research is to exercise a multiple regression analysis targeting on the facilities, which become the spatial distribution factor of one person household, with the independent variable gained from the concluded area calculated with the area ratio of the spatial unit followed by the service area analysis based on network. The spatial unit is the census output of Seoul, and based on this the interaction between the number of one person household according to age and the factors of its distribution. Also, the spatial regions - downtown, northeast, southeast, northwest, southwest - are designed as dummy variables and the results of each region are found out. As a result, the spatial regions occupied according to age are found to be varied - people in their 20s prefer housings near the college, 30s lease or the monthly rental housings, 40s the monthly rental housings, and over 60s the housing with the floor area of less than $40m^2$. Likewise, one person household has different types of housing environments preferred according to age, and thus a housing policy concerning this will have to be suggested.

• Korean Journal of Environmental Agriculture
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• v.28 no.1
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• pp.1-8
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• 2009

This study was aimed at assess environmental conservation functions by analyzing the change of land use areas in agricultural fields between 1999 and 2006, and comparing land surface temperature distribution between 1994 and 2006 in Yongin city. Land use maps of Yongin city were obtained from soil maps for 1999, Quickbird satellite images(less than 1 m) and parcel map for 2006. The land use area for Yongin city was in the order of forest > paddy field > upland > residence & building in 1999, and forest > residence & building > paddy field > upland in 2006. Decrease of paddy and upland fields reduced 34% and 41% of the capability of agricultural multifunctionality as to environment including flood control, groundwater recharge, and air cooling. Land surface temperature(LST) was derived from Landsat TM thermal infrared band acquired in September of 1994 and 2006 and classified into three grades. The results impplied that green vegetation in agricultural field and forest play an important role to reduce land surface temperature in warm season.

• Progress in Medical Physics
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• v.21 no.2
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• pp.153-164
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• 2010

To determine the clinical target volumes considering vascularity and cellularity of tumors, the software was developed for mapping of the analyzed biological clinical target volumes on anatomical images using regional cerebral blood volume (rCBV) maps and apparent diffusion coefficient (ADC) maps. The program provides the functions for integrated registrations using mutual information, affine transform and non-rigid registration. The registration accuracy is evaluated by the calculation of the overlapped ratio of segmented bone regions and average distance difference of contours between reference and registered images. The performance of the developed software was tested using multimodal images of a patient who has the residual tumor of high grade gliomas. Registration accuracy of about 74% and average 2.3 mm distance difference were calculated by the evaluation method of bone segmentation and contour extraction. The registration accuracy can be improved as higher as 4% by the manual adjustment functions. Advanced MR images are analyzed using color maps for rCBV maps and quantitative calculation based on region of interest (ROI) for ADC maps. Then, multi-parameters on the same voxels are plotted on plane and constitute the multi-functional parametric maps of which x and y axis representing rCBV and ADC values. According to the distributions of functional parameters, tumor regions showing the higher vascularity and cellularity are categorized according to the criteria corresponding malignant gliomas. Determined volumes reflecting pathological and physiological characteristics of tumors are marked on anatomical images. By applying the multi-functional images, errors arising from using one type of image would be reduced and local regions representing higher probability as tumor cells would be determined for radiation treatment plan. Biological tumor characteristics can be expressed using image registration and multi-functional parametric maps in the developed software. The software can be considered to delineate clinical target volumes using advanced MR images with anatomical images.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.1
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• pp.12-26
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• 2010

This study was conducted to investigate current states and management of the protected trees in Gangwon-do. There were 701 protected trees in 42 species designated by 2008, which were distributed at 425 places. Major species were Zelkova serrata(29%), Pinus densiflora(24%), Ulmus davidiana var. japonica(11%), and Ginkgo biloba(5%). The protected trees played various roles in the villages, mostly as sacred trees(43%). The 51% of protected trees were 300 years or more in age, the 53% were more than 20 m in height, and the 57% were more than 300 cm in girth at breast height. The 69% of the protected trees have been designated for protection in 1982 and the rest have been designated by the local cities by 2008. The species number of the protected trees in Youngseo region was greater than that of the Youngdong region. The major species were Zelkova serrata (33%) and Pinus densiflora(17%) in Youngseo region, and were Pinus densiflora (38%) and Zelkova serrata(19%) in Youngdong region. The ratio of native species to exotic species was 33:1 in Youngseo region, and were 25:6 in Youngdong region. The 29% of protected trees were located in the field, 28% in the mountain, and 25% in the villages. The 45% of the ground were covered by herbaceous plants, 39% exposed, and 10% gravel mulch. Most of the protected trees had good growing conditions. The 70% of the protected trees were under good maintenance, and the rest were under undesirable conditions. The soil characteristics of the protected tree areas in Gangwon-do were not much different from those of Korean average. It seemed to be necessary to increase designation of protected trees based on the tradition, history, local value and academic application in Gangwon-do. In addition, it is desirable to suggest plans to utilize and manage protected tree areas for enhancing the value of natural heritages in Gangwon-do.

• Economic and Environmental Geology
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• v.36 no.1
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• pp.27-38
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• 2003

Arsenic contamination around Au-Ag mining areas occurs mainly from the oxidation of arsenopyrite which is frequently contained in mine tailings. In weathered tailings, oxidation of sulfide minerals typically results in the formation of abundant ferric (oxy)hydroxides or (oxy)hydroxysulfates near the tailings surface, and arsenic may be associated with these secondary precipitates. In this study, solid phases of arsenic in weathered tailings of some Au-Ag mines were investigated through the SEM/EDS and sequential extraction analyses. The stability of As solid phases and the leaching potential were assessed with the variation of pH and Eh conditions. Oxidation of sulfides in the tailings samples was indicated by depletion of S molar concentrations compared to As and heavy metals. Under XRD examinations, jarosite as an Fe-oxyhydroxysulfate was found in the tailings of Deokeum, Dongil and Dadeok, and scorodite as an As-bearing crystalline mineral was identified from Dadeok which has the highest concentration of As (4.36 wt.%). Beudantite-like phases and some Pb-arsenates were also found under SEM/EDS analysis, and most of As phases were associated with Fe-(oxy)hydroxides and (oxy)hydroxysulfates despite a few arsenopyrite from Samgwang and Gubong. Sequential extraction analysis also showed that As was present predominantly as coprecipitated with Fe hydroxides from Dongil, Dadeok and Myungbong (72∼99%), and as sulfides (58%) and Fe hydroxide-associated forms (40%) from Samgwang and Gubong. In the tailings leaching experiment, As was released with high amounts by the dissolution of As-bearing Fe(oxy)hydroxysulfates in the lowest pH (2.7) conditions of Deokeum, and by desorption under alkaline conditions of Samgwang and Gubong. Higher leaching rates of arsenite(+3) were found under acidic conditions, which pose a higher risk to water quality. Changes in pH and Eh conditions coupled with microbial processes could influence the stabilities of the As solid phases, and thus, time amendments or landfilling of weathered tailings may result in enhanced As mobilization.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.4
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• pp.216-226
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• 2019

This study was to investigate the effect of the horse grazing intensity on the vegetation of the S. quelpaertensis, and the physiological changes of the horse. This experiment was conducted at the community of the S. quelpaertensis (altitude of 550m) with the grazing intensity of 1.0AU(500kg), 1.5AU(750kg) and 2.0AU(1,000kg) at 30m × 30m for one week, and then the growth characteristics of the S. quelpaertensis, the changes of the vegetation, the damages on trees and the changes in the physiological characteristics of the horses was investigated and compared before and after the horse grazing. As the results, the 2.0AU grazing land showed that the culm number had the inverse correlation (r=-0.902, P<0.01) to the other lands and the species diversity index of lower-level vegetation showed the correlation (r=0.773, P<0.01) as increasing the grazing intensity.