• Journal of the Korean association of regional geographers
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• v.6 no.3
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• pp.37-52
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• 2000

Generally speaking, the metropolitan agricultural regions have some advantages from the high accessibility to markets. But agriculture inevitably rests on the biological process. This study shows what characteristics of the agricultural management are found in these less favored metropolitan areas with bad natural conditions and how farm household live there. From the view point of farm household, the quality of labors they can get is quite low, and insufficient in quantity. The shortage of labor can be made up for the farming on Trust Farming System And the relatively less favored agricultural conditions prevent people from immigrating into these kind of areas, if they don't have any relationship with there. With bad natural conditions, the farm households usually cultivate relatively small areas for the purpose of self-sufficiency, and with smaller cultivating units(Baemi) of the land than in open fields. The scale of the agricultural management is largely affected by the ages of agricultural managers. The more aged the managers are, the smaller scale of the agricultural management. How to use lands is determined in accordance with the natural conditions such as percentage of sunshine and accessibility to drainage facilities -the two major factors- and more. Either owner-run farmlands or leased farmlands doesn't show any difference in each growing crops. Depending on the conditions of the lands, rice paddy is used for growing rice and field is used for growing self sufficient plants including vegetables for the farm household. Although the lack of infrastructure causes the inconvenience of living, and there exist less favored agricultural conditions, this kind of life and agricultural management style -self-sufficiency type- seems to be sustained quite longer. The less favored natural conditions for farming keeps the agricultural management style from being developed to be the level of commercialization. And the poor economic situation of farmers are continuing again and again. With the result of this study, there should be two conditions to be established previously if they want to develop these regions. First, each farm household should get to know of the importance of commercialization and try to spread it. The commercialization. should be attained through the expansion of the environmental friendly agriculture and the improvement of the previously established distribution system of the crops. Secondly, there should be a support from the government. The support will include the expansion of the infrastructures for fanning to improve the fanning conditions and the compensation system directly from the government to the farmers.

• Economic and Environmental Geology
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• v.29 no.1
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• pp.65-75
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• 1996

Sulfate reduction and the precipitation of metal sulfides may have great potential to improve water quality of mine effluents in wetland treatment systems. Laboratory experiments using sulfate reducing bacteria (SRB) and limestone to treat effluents from the abandoned Dalsung tungsten-copper mine show that encouraging results, that have been attributed to sulfate reduction. Fe, Al, Cd, Cu and Zn are reduced to below detection limits with $99{\sim}100%$ metal removal rates, Mn is reduced by at least 90% to below 8.0 mg/l, and the pH is raised from 5.12 to 7.60 after 53 days of experiments. In the staged design, laboratory experiments are initiated to determine what would be reasonable substrate materials for remediation of the mine effluents. A substrate mixture containing 70% oak compost and 30% mushroom compost maintains $0.03{\sim}0.04mM$ of lactate, which provides good condition for the SRB granule. A downflow SRB wetland system is proposed as follows : 1) The lower part of the treatment system consists with a 25 cm thick layer of high quality (above 95% of $CaCO_3$) of limestone; 2) The geotextile (geonet) is recommended to be spread on the limestone bed to prevent clogging the limestones with the substrates; 3) The mixture of substrates with 70% oak and 30% spent mushroom composts, and SRB granules overlain on top of the geonet with 25 cm height. The sizes of the passive treatment systems are calculated according to metal loading and permeability criteria : 1) $220m^3$ ($15{\times}15{\times}1m$) for -1 level effluents; 2) $28m^3$ ($5.3{\times}5.3{\times}1m$) for -2 level; and 3) $2700m^3$ ($52{\times}52{\times}1m$) for the -3 level. The -3 level system needs to be broken down into 5 to 15 cells.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.4
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• pp.437-446
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• 2012

As a part of establishing suitability classification for forage production, use of the national soil and climate database was attempted for Italian ryegrass (Lolium multiflorum Lam., IRG) in Gangwon Province. The soil data base were from Heugtoram of the National Academy of Agricultural Science, and the climate data base were from the National Center for Agro-Meteorology, respectively. Soil physical properties including soil texture, drainage, slope available depth and surface rock contents, and soil chemical properties including soil acidity and salinity, organic matter content were selected as soil factors. The crieria and weighting factors of these elements were scored. Climate factors including average daily minimum temperature, average temperature from March to May, the number of days of which average temperature was higher than $5^{\circ}C$ from September to December, the number of days of precipitation and its amount from October to May of the following year were selected, and criteria and weighting factors were scored. The electronic maps were developed with these scores using the national data base of soil and climate. Based on soil scores, the area of Goseong, Sogcho, Gangreung, and Samcheog in east coastal region with gentle slope were classified as the possible and/or the proper area for IRG cultivation in Gangwon Province. The lands with gentle or moderate slope of Cheolwon, Yanggu, Chuncheon, Hweongseong, Pyungchang and Jeongsun in west side slope of Taebaeg mountains were classified as the possible and/or proper area as well. Based on climate score, the east coastal area of Goseong, Sogcho, Yangyang, Gangreung and Samcheog could be classified as the possible or proper area. Most area located on west side of the Taebaeg mountains were classified as not suitable for IRG production. In scattered area in Chuncheon and Weonju, where the scores exceeded 60, the IRG cultivation should be carefully managed for good production. For better application of electronic maps.

• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.90-104
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• 2001

This study is aimed to analyze and to evaluate the revegetation and soil conservation technology in desertification-affected sandy land, resulting from the project of "Studies on the desertification combating and sand industry development". Main native plants for combating desertification : The general characteristics of vegetation distribution in desertified regions are partially concentrated vegetation distribution types including the a) desert plants in low zone of desert or sanddune of depressed basin, b) salt-resistant plants around saline lakes, c) grouped vegetation with Poplar and Chinese Tamarix of freshwater-lakes, saline-lakes and river-banks, d) gobi vegetation of gravel desert and e) grassland and oasis-woods around the alluvial fan of rivers, etc. Generally, Tamarix ehinensis Lour., Haloxylon ammodendron Bunge., Calligonum spp., Populus euphratica Oliver., Elaeagnus angustifolia L., Ulmus pumila L., Salix spp., Hedysarum spp., Caragana spp., Xanthoceras sorbifolia Bunge., Nitraria tangutorum Bobr., Lespedeza bicolor, Alhagi sparsifolia Shap., Capparis spinosa L., Artemisia arenaria DC., etc. are widely distributed in desertified regions. It is necessary for conducting research in the native plants in desertified regions. Analysis of intensive revegetation technology system for combating desertification : In the wind erosion region, the experimental research projects of rational farming systems (regional planning, shelterbelts system, protection system of oasis, establishment of irrigation-channel networks and management technology of enormous farmlands, etc.), rational utilization technology of plant resources (fuelwood, medicinal plants, grazing and grassland management, etc.), utilization technology of water resources (management and planning of watershed, construction of channel and technology of water saving and irrigation, etc.), establishment of sheltetbelts, control of population increase and increased production technology of agricultural forest, fuelwood and feed, etc. are preponderantly being promoted. And in water erosion region, the experimental research projects of development of rational utilization technology of land and vegetation, engineering technology and protection technology of crops, etc. are being promoted in priority. And also, the experimental researches on the methods of utilization of water (irrigation, drainage, washing and rice cultivation, etc.), agricultural methods (reclamation of land, agronomy, fertilization, seeding, crop rotation, mixed-cultivation and soil dressing works, etc.) and biological methods (cultivation of salt-resistant crops and green manure and tree plantation, etc.) for improvement of saline soil and alkaline soil in desertified-lands are actively being promoted. And the international cooperations on the revegetation technology development projects of desertified-lands are sincerely being required.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.56-63
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• 2018

The management of Combined Sewer Overflows(CSOs) and Separated Sewer Overflows(SSOs) discharge directly to the effluent system in an untreated state, which occurs when the facility capacity is exceeded due to heavy rain, has become an important issue in recent years as the heavy rain becomes a regular phenomenon. Despite the continuous development of filtration technology, targeting densely populated urban areas, CSOs are rarely applied. Therefore, this study was carried out to optimize the process to apply CSOs in a pilot-scale horizontal flow filtration system with a rope-type synthetic fiber. The research was carried out in two steps: a preliminary study using artificial samples and a field study using sewage. In the preliminary study using an artificial sample, head loss of the filter media itself was analyzed to be approximately 1.1cm, and the head loss was increased by approximately 0.1cm as the linear velocity was increased by 10m/hr. In addition, the SS removal efficiency was stable at 81.4%, the filtration duration was maintained for more than 6 hours, and the average recovery rate of 98% was obtained by air backwashing only. In the on-site evaluation using sewage, the filtration duration was approximately 2 hours and the average removal efficiency of 83.9% was obtained when belt screen (over 450 mesh) was applied as a pre-treatment process to prevent the premature clogging of filter media. To apply the filtration process to CSOs and SSOs, it was concluded that the combination with the pre-treatment process was important to reinforce the hydraulic dimension for the stable maintain of operation period, rather than efficiency. Compared to the dry season, the quality of incoming sewage was lower in the rainy season, which was attributed to the characteristics of the drainage area with higher sanitary sewerage. In addition, the difference in removal efficiency according to the influent quality of the wet season and dry season was small.

• The Korean Nurse
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• v.36 no.1
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• pp.59-76
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• 1997

The purposes of this study were to identify the contents and satisfaction level of the patients received home care service, and to compare the differences of the contents by the characteristics of the patients. Seventy eight patients received home care service from 1st Jan. to 30th Sept., 1996 were data-collected to analyze the contents and outcomes of home care service. Sixty-nine patients currently receiving home care service were participated to evaluate the satisfaction level of home care service. The data were analyzed using mean, standard deviation, $x^2$ test, and ANOVA by SPSS $PC^+$ program. The findings of this study were as follow : 1. The contents & outcomes of home care service 1) The mean age of the subjects was 64.4 years: 58% of them were female. Those who living in Seoul were 83% and the rest of the subjects was living in Kyung-Gi. 2) The subjects who had one diagnosis were 41%. Over 60% of them had the disease of neurologic & sensory system. 3) The mean number of visit was 6. Only one visit was 22%. The mean time of care was 79 minutes. Duration of visit from 31 minutes to 60 minutes were 47 %. The subjects who terminated the visit because of death were 67.3%. 62% of the persons who referred them to the home care service were nurses. 4) The pain after the service was more relieved than before. The amounts of intake, the degree of bed sore, edema & fracture after the service were more improved than before. Health status after the service was improved in general. 5) There were significant differences between initial and last conscious level in tracheostomy care & oxygen inhalation care. There was significant difference between initial and last degree of activity in blood sugar check. 6) There were significant differences on the number of visit in assessment of the status, evaluation & observation, vital sign check, skin care, injection, medication, bed sore care, colostomy care, relaxation therapy for pain relief, patient education, family care, exercise therapy, position change, supply of disinfected equipments and infection control. There were significant differences on visiting time in nasogastric tube care, drainage tube care and oxygen inhalation care. 2. The satisfaction level of home care service 1) 50% were male. Over 60 years of the subjects was 61 %. Those who living in Seoul were 82%. 2) The subjects who had one or two diagnosis were 32% respectively. 55% of the persons who referred them to the home care service were nurses. 3) Total level of satisfaction of home care service was very high. 4) The older the age, the higher the satisfaction level. The larger the number of visit, the higher the satisfaction level. 5) The subjects who were in cloudy state were higher level of satisfaction than in alert or coma state. The subjects whose activity were normal or who needed assistance were higher level of satisfaction than bedridden or immobilized subjects. These findings suggested that the patients had substantial need for posthospital care. They tended to be elderly and to have experienced the wide range of health problems associated with aging, chronicity, including limitations in activities, and other serious health problems. So, the nationwide home care systems beyond the limit of demonstration program by local association and the development of the effective financial system of home based health care are necessary for the clients who are in need of home care.

• Journal of Korean Society of Disaster and Security
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• v.12 no.4
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• pp.1-13
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• 2019

Recently, as the occurrence frequency of sudden floods due to climate change increased, it is necessary to install the facilities that can cope with the initial stormwater. Most researches have been conducted on the design of facilities applying the Low Impact Development (LID) and the reduction effect on rainfall runoff to examine with 1D or 2D numerical models. However, the studies on the examination about flow characteristics and stability of pipe network systems were relatively insufficient in the literature. In this study, the stability of the pipe network system in rainwater storage tank was examined by using 3D numerical model, FLOW-3D. The changes of velocity and dynamic pressure were examined according to the number of rainwater storage tank and compared with the design criteria to derive the optimal design plan for a rainwater storage tank. As a results of numerical simulation with the design values in the previous study, it was confirmed that the velocity became increased as the number of rainwater storage tank increased. And magnitude of the velocity in pipes was formed within the design criteria. However, the velocity in the additional rainwater storage pipe was about 3.44 m/s exceeding the allowable range of the design criteria, when three or more additional rainwater storage tanks were installed. In the case of turbulence intensity and bottom shear stress, the bottom shear stress was larger than the critical shear stress as the additional rainwater storage was increased. So, the deposition of sediment was unlikely to occur, but it should be considered that the floc was formed by the reduction of the turbulence intensity. In addition, the dynamic pressure was also satisfied with the design criteria when the results were compared with the allowable internal pressure of the pipes generally used in the design of rainwater storage tank. Based on these results, it was suitable to install up to two additional rainwater storage tanks because the drainage becomes well when increasing of the number of storage tank and the velocity in the pipe becomes faster to be vulnerable to damage the pipe. However, this study has a assumption about the specifications of the rainwater storage tanks and the inflow of stormwater and has a limitation such that deriving the suitable rainwater storage tank design by simply adding the storage tank. Therefore, the various storage tank types and stormwater inflow scenarios will be asked to derive more efficient design plans in the future.

• Journal of Korea Water Resources Association
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• v.40 no.11
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• pp.887-898
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• 2007

A physically based semi-distributed model, SWAT was applied to the Chungju Dam upstream watershed in order to investigate the spatial and temporal characteristics of watershed sediment yields. For this, general features of the SWAT and sediment simulation algorithm within the model were described briefly, and watershed sediment modeling system was constructed after calibration and validation of parameters related to the runoff and sediment. With this modeling system, temporal and spatial variation of soil loss and sediment yields according to watershed scales, land uses, and reaches was analyzed. Sediment yield rates with drainage areas resulted in $0.5{\sim}0.6ton/ha/yr$ excluding some upstream sub-watersheds and showed around 0.51 ton/ha/yr above the areas of $1,000km^2$. Annual average soil loss according to land use represented the higher values in upland areas, but relatively lower in paddy and forest areas which were similar to the previous results from other researchers. Among the upstream reaches, Pyeongchanggang and Jucheongang showed higher sediment yields which was thought to be caused by larger area and higher fraction of upland than other upstream sub-areas. Monthly sediment yields at the main outlet showed same trend with seasonal rainfall distribution, that is, approximately 62% of annual yield was generated during July to August and the amount was about 208 ton/yr. From the results, we could obtain the uniform value of sediment yield rate and could roughly evaluate the effect of soil loss with land uses, and also could analyze the temporal and spatial characteristics of sediment yields from each reach and monthly variation for the Chungju Dam upstream watershed.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.1
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• pp.6-11
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• 1989

This investigation was conducted to get basic informations on land consolidation works and soil management for arable land. The characteristics of geometrical features of mapping units in the detailed soil maps of Korea were measured from 70 soil series (565 soil phases) by using a picture analysis system. The results obtained were as follows: 1. The mean values of the mapping units in extent, periphery, diameter of long axis and short axis, roundness and number of acute angles were 22.0ha, 2.267m, 911m, 0.104, and 3.5, respectively. It was suggested that "Simplicity Index of Mapping Unit", $=\frac{Extent\;in\;ara}{Length\;of\;boundary\;periphery\;in\;meter}{\times}\frac{1}{number\;of\;acute\;angle}$ be valuable to judge the complexity degrees of mapping units. 2. The size of mapping unit among physiographyic position was shown in order of Alluvial plains > Fluviomarine plains > Terraces > Hills > Fans > Mt. foot slopes > Valleys, and the simplicity index of mapping units also showed similar order of the extent. 3. The size and the simplicity index of the soils developed on plains with silty textured imperfectly drained were higher than the soils developed on sloped land with loamy textured. As the slopes getting steeper or relatively better in soil drainage, the size and the simplicity index became smaller. 4. The relationship between the simplicity index and the size of the farm unit divides by the land consolidation works was positively correlated. And it was concluded that the parcelling of the farm unit divides by the planning of land consolidation should be based on the soil boundaries of the detailed soil maps for mechanized or collaborated farming.

• Economic and Environmental Geology
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• v.56 no.3
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• pp.301-310
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• 2023

Ferrihydrite is an iron oxide mineral that is easily found in the natural environment, including acid mine drainage, and has a low crystallinity and high specific surface area, resulting in high reactivity with other ions, and can remove environmentally hazardous substances. However, because ferrihydrite is a metastable mineral, there is a possibility of releasing adsorbed ions by phase transformation to other minerals having low surface area and high crystallinity. In this study, the adsorption characteristics of arsenate, chromate, and selenate on ferrihydrite and the oxyanion removal efficiency of ferrihydrite were studied considering mineral phase transformation. At both pH 4 and 8, the adsorption of oxyanions used in the study were in good agreement with both Langmuir and Freundlich adsorption models except for selenate at pH 8. Due to the difference in surface charge according to pH, at pH 4 a higher amount of ions were adsorbed than at pH 8. The adsorption amount were in the order of arsenate, chromate, and selenate. These different adsorption models and adsorption amounts were due to different adsorption mechanisms for each oxyanions on the surface of ferrihydrite. These adsorption characteristics were closely related to changes in the mineral phase. At pH 4, a phase transformation to goethite or hematite was observed, but only a phase transformation to hematite was observed at pH 8. Among the oxyanion species on ferrihydrite, arsenate showed the highest adsorption capacity and hardly caused phase transformation during the experimental period after adsorption. Contrary to this, chromate and selenate showed faster mineral phase transformation than arsenate, and selenate had the lowest retardation effect among the three oxyanions. Ferrihydrite can effectively remove arsenate due to its high adsorption capacity and low phase transformation rate. However, the removal efficiency for other two oxyanions were low by the low adsorption amount and additional mineral phase transformation. For chromate, the efficient removal is expected only at low concentrations in low pH environments.