• The Journal of Engineering Geology
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• v.19 no.2
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• pp.205-215
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• 2009

The conventional numerical models to analyze flow in subsurface porous media under the transient state usually generate numerical oscillation and unstability due to local flux domain for critical cases such as infiltration into initially dry soil during rainfall period. In this case, it is required refined mesh and small time step, but it decrease efficiency of computation. In this study, numerical unstability in discontinuity domain is removed by applying particle tracking algorithm to simulate unsteady subsurface flow with inflow boundary condition. Finally the hybrid LE FEM improving numerical stability is proposed. The hypothetical domains with unsteady uniform and nonuniform flow field were used to demonstrated algorithm verification. In comparison with analytic solution, we obtained reasonable results and conducted simulation of hypothetical 3-D recharge/pumping area. The proposed algorithm can simulate saturated/unsaturated porous media with more practical problems and will greatly contribute to accuracy and stability of numerical computation.

• The Korean Journal of Ecology
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• v.28 no.2
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• pp.85-92
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• 2005

This study emphasizes syntaxonomy and syndynamics of intermediate (Zwischen) moor (area: 14,000 $m^2$) at Mt. Shinbul in Yangsan, southeastern Korean Peninsula. A total of 105 vascular plant species including 26 monitor-species were recorded. Analysis by the $Z\"{u}rich$-Montpellier School's method distinguished eight vegetation units: Eleocharitis-Blyxetum echinospermae ass. nov., Eriocaulon sikokianum-Utricularia racemosa community, Eleocharis wichurai-Molinia japonica community, Platanthero-Molinietum japonicas, Miscanthus sinensis for. purpurascens community, Tripterygium regelii community, Symplocos chinensis-Quercus mongolica community, Symplocos chinensis-Quercus dentata community. PCoA (Principal Coordinates Analysis) shows that vegetation changes and distributional aspects are associated with both moisture condition and sunlight on the ground layer and soil nutrient level (mesotrophic to oligotrophic). Most important to Molinietea japonicas being representative intermediate moor vegetation at the southeasternmost fringe of the Korean Peninsula is the local cooling effect by mountainous cloud and mist zone resulting in shorter and wetter growing season. The Yangsan moor vegetation was compared with earlier descriptions of related Mujechi moor from anthropogenic and natural moor vegetations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.927-935
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• 2011

In-situ California Bearing Ratio(CBR) test has been widely used for evaluating the subgrade condition in pavements. However, because the in-situ CBR test is expensive and takes time for operation, it is difficult to figure out the in-situ characteristics of subgrade strength in detail. For faster and economical operation, the Dynamic Cone Penetrometer(DCP) has been often utilized for estimating the subgrade strength in the field. The purpose of this paper is to determine the relationship between CBR value and DCP index of the embankment constructed with mixtures of soil and waste lime. Waste lime used in this study is producted as a by-product in the manufacturing process of making $Na_2CO_3$ from local chemical factory in Incheon. In this field measurement, the geotechnical tests such as field water content, field density, field CBR test, and dynamic cone penetration test were conducted.

• The Korean Journal of Quaternary Research
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• v.16 no.2
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• pp.9-21
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• 2002

In Korea, many open-air upper palaeolithic sites are located at the river valley, particularly exposed in gently rotting terrain along the river course. They are situated at an altitude less trail 30 m above present river bottom, and covered with the blankets of slope deposits of several meters in thickness. The purpose of this research is to eluridate depositional and vegetational environment of the alluvial upper palaeolithic Jangheung-ri sites on the basis of analytical properties of grain size population, chronology, palynology, soil chemistry and clay mineralogy and magnetic susceptibility of the Jangheung-ri Quaternary formations. The lithostratograpy of Jangheung-ri sit is subdivided into 3 layers based on the depositional sequence and radiocarbon ages. From bottom to top, they are composed of slope deposits with lower paleosol layers, young fluvial sand and gravel with backswamp organic muds, and upper paleosol layers. The upper paleosol was formed under rather dry climatic condition between each flooding period. Dessication cracks were prevalent in the soil solum which was filled with secondarily minuted fragments due to pedogenetic process. The soil structure shows typical braided-typed cracks in the root part of cracking texture, and more diversified pattern of crackings downward. The young fluvial sand gravel were formed by rather perennial streams after LGM. The main part of organic muds was particularly formed after 15Ka. Local backswamp were flourished with organic muds and graded suspension materials in the flooding muds were intermittently accumulated in the organic muds until ca. 11Ka. This episode was associated with migration of Nam River toward present course. Organic muds were formed in backswamp or local pond. Abies/Picea-Betula with Ranunculaceae, Compositae, Cyperaceae were prevalent. This period is characterized with B$\Phi$lling, Older Dryas, Allerod, and Younger Dryas (MIS-1). Stone artefacts were found in the lower paleosol layers formed as old as 18Ka-22Ka. Based on the artefacts and landscape settings of the Jangheung-ri site, it is presumed that settlement grounds of old people were buried by frequent floodings of old Nam River, the river-beds of which were heavily fluctuated laterally and river-bed erosions were activated from south to north in Jangheung-ri site until the terminal of LGM9ca 17Ka).

• Journal of Bio-Environment Control
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• v.6 no.3
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• pp.159-167
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• 1997

To cope with the mass-production and supply of plug seedling, the supply of transplanters is necessary. In the study, a transplanting test was carried out to find the optimum working condition in the mechanizd transplantation and to acquire the basic data for the improvement of transplanters by the research and analysis of working capacity of the local manual transplanters. The size of hopper affected transplanting stand and rate. Re-irrigation was required for the transplanted seedlings because they wilt 1 day after the transplanting if soil compaction is incomplete. Consequently, back-forth-left-right compaction method was good for soil covering and compaction. It may be thought to increase the amount of irrigation water at the time of transplanting by double-irrigation mechanism, but it needs to increase the larger water tank which makes the operation uneasy. So, assuming the working model by 1 or 2 operators with the machine size as small as possible, it seemed that eliminating of automatic irrigation method was desirable in view of efficiency. Though semiautomatic transplanter needs some structural improvements, it seemed still suitable for transplanting of plug seedlings such as 45-day red pepper seedlings in 128-hole tray and 25-day Chinese cabbage seedling in 128-hole tray. If traveling speed of the transplanter is limited to less than 14 m/min, with the transplanting depth of 2~3cm and transplanting space of 30cm.

• International Journal of Highway Engineering
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• v.4 no.2 s.12
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• pp.33-42
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• 2002

The cracks in the pavements result from drying shrinkage, temperature change, repeated traffic loadings and so on. The reduction of soil support, spatting and many local failures are caused by water and incompressible foreign materials infiltrated into the cracks. In order to reduce this kind of problems the crack width must be controlled and managed by the accurate measurement. The current method is a visual survey using a microscope, which requires traffic blocking. The purpose of this study is to find the best condition to measure accurate crack width using automated pavement condition survey equipment running at the similar speed as other vehicles. In this study pavement surfaces are filmed on an enlarged scale by the camera with a zoom lens, and then the proper focal distance is determined according to the crack width through a pilot survey. The conditions for measurement of the accurate crack width using the image processing technique are suggested by comparing crack widths surveyed using a microscope in the field with those computed by various factors in the image processing program, STADI-2. In conclusion, the camera with a focal distance of 75m could detect crack range of 0.5mm$\sim$1.2mm In width with an accuracy of 80% for CRCP. The camera with a focal distance of 12.5mm could detect crack range of 1.8mm$\sim$3.3mm in width with an accuracy of 90% for asphalt pavement.

• Microbiology and Biotechnology Letters
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• v.33 no.3
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• pp.194-199
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• 2005

In oder to select an antifungal substance-producing antagonistic bacterium against Fusarium oxysporum casuing fusarium wilt on tomato, strain BK4 was isolated from local soil of Gyeoungbuk and was identified as Bacillus thuringiensis by 16s rDNA analysis, biochemical test, and Mcirolog TM 3.0 System. The antibiotic of B. thuringiensis BK 4 was highly produced at $30^{\circ}C$ in nutrient broth (pH 9.0). The crude antibiotic was even stable at $121^{\circ}C$ and more stable at slight alkalic condition than acid condition. It was also remained $50{\%}$ activity at pH 3.0. B. thuringiensis BK4 showed the inhibition of spore germination and the biocontrol ability against F. oxysporum causing fusarium wilt of tomato in vivo test. According to these results, B. thuringiensis BK4 was enough to use with a microbial agent for biocontrol against fusarium wilt.

• Korean Journal of Environment and Ecology
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• v.26 no.2
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• pp.210-218
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• 2012

This study was carried out to analyze the vegetation properties, soil characteristics and ordination of Bletilla striata population in South Korea. The $Bletilla$ $striata$ population was classified into $Juniperus$ $rigida$ dominant population, $Rhododendron$ $yedoense$ var. $poukhanense$ dominant population, $Rhus$ $javanica$ dominant population, $Bletilla$ $striata$ typical population. $Bletilla$ $striata$ were mainly distributed along the coast of south-western regions of the Korean penninsula and it's population was located at an elevation of 4m to 40m. In the study sites, soil organic matter, total nitrogen, available phosphate, exchangeable potassium, exchangeable calcium, exchangeable magnesium, cation exchange capacity and soil pH were 2.38-6.70%, 0.09-0.27%, 1.81-6.85mg/kg, 1.08-1.72$cmol^+/kg$, 3.56-7.71$cmol^+/kg$, 1.52-3.21$cmol^+/kg$, 5.28-16.95$cmol^+/kg$ and 4.60-6.01 respectively. $Rhododendron$ $yedoense$ var. $poukhanense$ dominant population was found in the steep sloped area that has high percentage of organic matter, total nitrogen, cation exchange capacity and pH than other populations. $Rhus$ $javanica$ dominant population was found in the gentle sloped area that has less percentage of organic matter, total nitrogen, cation exchange capacity and pH. $Juniperus$ $rigida$ dominant population and $Bletilla$ $striata$ typical population were found in the medium sloped area that has medium percentage of organic matter, total nitrogen, cation exchange capacity and pH. Current status of $Bletilla$ $striata$ habitats is very vulnerable with local development constantly threatening the species' survival. Thus, concrete conservation plans to protect natural habitats should be set up as soon as possible.

• Korean Journal of Heritage: History & Science
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• v.43 no.1
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• pp.190-211
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• 2010

The purpose of this paper is to provide the preliminary data for maintenance of old trees of natural monuments and establishing protection projects. Accordingly, growth conditions, location circumstances, environment and protection management were analyzed for old trees at 34 sites in Gyeongsangbuk-do. Tree forms, crown, trunk and trees' health, leaves volume were analyzed in survey sites. As the results, the growth of Picrasma quassioides in Songsadong, Andong-si and Catalpa ovata in Hongwon-ri, Cheongsong-gun were not in good condition, along with other old trees of 6 cities (Quercus variabilis in Susan-ri, Uljin-gun, Juniperus chinensis in Hujeong-ri, Uljin-gun, Pyrus ussuriensis in Ssangjeon-ri, Uljin-gun, Salix glandulosa var. pilosa in Deokchon-ri, Cheongdo-gun, Pinus densiflora for. multicaulis in Hwasan-ri, Mungyeong-si, Pinus densiflora in Daeha-ri, Mungyeong-si). Accoding to these results, protection project and consistent monitoring are necessary. The analysis results of growth conditions per location circumstances showed that the old trees in the small spaces with large traffic of people were in bad condition. Therefore, it is necessary to secure sufficient space and soil improvement for such trees. The analysis results of growth conditions per species showed that Zelkova serrata, Quercus spp., Pinus densiflora are in good condition while Salix koreensis and others, i.e. a singular tree, are in poor condition. Thus, relatively smaller individuals and separately situated trees need careful management in their protection. The analysis results of trunk's growth ratio showed that Pinus densiflora, Ginkgo biloba, Zelkova serrata are in good condition whereas Juniperus chinensis, Quercus variabilis, Salix koreensis are not. It is a recent trend that tree surgeries are gradually decreasing; there are a number of damaged trees with no maintenance/management, and several sites requiring mend trunks management and cabling, bracing in protection and management projects. Hence, in the future, local government and management organizations should plan for systematic management and establish a protection plan for the natural monument trees. Also, 12 sites were found to be in need to purchase lands in order to secure the growth spaces, and since most of these areas are available for purchase, it is needed to promote a budget and purchase those areas through persuasion of the owner. These areas seems crucial in order to maximize the effect of conservation efforts and budgets for the preservation and restoration of the old trees.

• Journal of Sericultural and Entomological Science
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• v.49 no.2
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• pp.51-55
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• 2007

Investigation of atmospheric data and rearing results was conducted to analyze the effects of atmospheric factors such as temperature and precipitation on silkworm in 8 rearing places in which local adaptation test was being conducted with different mulberry growth condition, soil and atmosphere during spring and autumn rearing season of 2006. The atmospheric characteristics of spring rearing time are as follows. The average temperatures of young silkworm, old silkworm, mounting were $17.7^{\circ}C$, $19.8^{\circ}C$, $21.5^{\circ}C$ respectively, and $1^{\circ}C$ higher than normal year. The precipitation of young silkworm, old silkworm, mounting were 15.1 mm, 6.9 mm, 7.0 mm, respectively, and 22.9 mm lower than normal year in old silkworm and mounting. The daylight hours in larval stage was 1.7 hour shorter than normal year, but no difference in mounting. Thus precipitation was lower and temperature was higher than normal year in 2006. The rearing results of 2006 were 1 kg lower than normal year in cocoon yields per 10,000 3 rd molted larvae, single cocoon weight and cocoon shell percentage were a little higher. The atmospheric characteristics of spring rearing season are as follows. The average temperatures of young silkworm, old silkworm, mounting were $25.1^{\circ}C$, $20.5^{\circ}C$ and $19.9^{\circ}C$ respectively, temperature in young silkworm was $1^{\circ}C$ higher than normal year, and temperature in old silkworm was $1.3^{\circ}C$ lower than normal year. The precipitation of young silkworm, old silkworm, mounting were 110.2 mm, 4.6 mm, 3.7 mm, respectively and there were little differences compared to normal year. The atmospheric condition of 2006 which was similar to normal year did not affect the autumn rearing results of 2006. Namely, the single cocoon weight and cocoon shell weight were not different from normal year, and the same was cocoon shell percentage.