• Journal of Korea Water Resources Association
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• v.52 no.1
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• pp.35-49
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• 2019

This study proposes a new method for categorizing the hydrological soil groups by considering the recent revision results of soil series. Also, the proposed method is evaluated by comparing the categorizing result with those based on existing three different methods. As an example, the proposed method is applied to Jeju Island to estimate the CN value, which is then compared with CN values estimated by applying the existing three different methods. Summaries of the results are as follow. (1) The revision result since 2007 shows that the soil texture has been changed in the 43 soil series, the drainage class in the 1 soil series, the permeability in the 15 soil series, and the impermeable layer in the 26 soil series. (2) The categorizing result of hydrological soil groups by applying the proposed method shows that the group B is the most dominant group covering up to 49.25%. On the other hand, one of the existing method of 1987 provides the group C as the most dominant group (46.43%). Method of 1995 defines the group B as the most dominant group (27.69%). The other method of 2007 distinguishes the group D (35.82%) to be the most dominant group. (3) Also, the CN value estimated by applying the proposed method to Jeju Island is found to be smaller than those based on existing three methods. This result indicates the possible overestimation of the CN value when applying the existing three methods.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.60-66
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• 2020

Torrential rain causes landslide damage every year. In particular, the 2011 downpour caused landslides at numerous points throughout Mt. Woomyeon, which resulted in considerable damage to people and property. Because it occurred in an urban area, this case became a major social issue and received public attention. Measures were quickly implemented for multilateral investigations and recovery. Landslides caused by heavy rain are greatly affected by rainfall at the time. Landslides from the upper part erode the flow path, increasing the size, causing much damage to the lower part. This study selected a rural village area among the damaged areas of Mt. Woomyeon, and analyzed the change in terrain profile before and after a landslide using the DSM data obtained from airborne LiDAR. This area can be divided into three hydrological basins. For each basin, the analysis was performed on the average slope of each part of the flow path, as well as the erosion and deposition due to soil flow. As a result of the analysis, it was estimated that the total amount of soil from the Jeonwon village was 15,300㎥. These field data based on GIS can be used as basic information to predict damage in the case of a similar disaster, and it can be helpful in analyzing the results of various debris flow simulations.

• Journal of the Korean Geographical Society
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• v.29 no.3
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• pp.233-252
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• 1994

One of major advantages of Lumped model is its ability to simulate extended flows. A further advantage is that it requires only conventional, readily available hydrological data (rainfall, evaporation and runoff). These two advantages commend the use of this type of model for the analysis of the hydrological effects of landuse change. Experimental Catchment(K11) of Kimakia site in Kenga experienced three phases of landuse change for sixteen and half years. The Institute of Hydrology offered the hydrological data from the catchment for this research. On basis of Blackie's(l972) 9-parameter model, a new model(R1131) was reorganized in consideration of the following aspects to reflect the hydrological characteristics of the catchment: 1) The evapotranspiration necessary for the landuse hydrology, 2) high permeable soils, 3) small catchment, 4) input option for initial soil moisture deficit, and 5) othel modules for water budget analysis. The new model is constructed as a 11-parameter, 3-storage, 1-input option model. Using a number of initial conditions, the model was optimized to the data of three landuse phases. The model efficiencies were 96.78%, 97.20%, 94.62% and the errors of total flow were -1.78%, -3.36%, -5.32%. The bias of the optimized models were tested by several techniques, The extended flows were simulated in the prediction mode using the optimized model and the data set of the whole series of experimental periods. They are used to analyse the change of daily high and low-flow caused by landuse change. The relative water use ratio of the clearing and seedling phase was 60.21%, but that of the next two phases were 81.23% and 83.78% respectively. The annual peak flows of second and third phase at a 1.5-year return period were decreased by 31.3% and 31.2% compared to that of the first phase. The annual peak flow at a 50-year return period in the second phase was an increase of only 4.8%, and that in the third phase was an increase of 12.9%. The annual minimum flow at a 1.5-year return period was decreased by 34.2% in the second phase, and 34.3% in the third phase. The changes in the annual minimum flows were decreased for the larger return periods; a 20.2% decrease in the second phase and 20.9% decrease in the third phase at a 50-year return period. From the results above, two aspects could be concluded. Firstly, the flow regime in Catchment K11 was changed due to the landuse conversion from the clearing and seedling phade to the intermediate stage of pine plantation. But, The flow regime was little affected after the pine trees reached a certain height. Secondly, the effects of the pine plantation on the daily high- and low-flow were reduced with the increase in flood size and the severity of drought.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.1
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• pp.16-25
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• 2012

To calculate the total mass flux that change in dry and flood season in the Yeomha Channel of Gyeonggi Bay, the 13 hour bottom tracking observation was performed from the southern extremity. The value of the total mass flux(Lagrange flux) was calculated as the sum of the Eulerian flux value and stroke drift value and the tidal residual flow was harmonically analyzed through the least-squares method. Moreover, the average during the tidal cycle is essential to calculate the mass flux and the tidal residual flow and there is the need to equate the grid of repeatedly observed data. Nevertheless, due to the great differences in the studied region, the number of vertical grid tends to change according to time and since the horizontal grid differs according to the transport speed of the ship as a characteristic of the bottom tracking observation, differences occur in the horizontal and vertical grid for each hour. Hence, the present study has vertically and horizontally normalized(sigma coordinate) to equate the grid per each hour. When compared to the z-level coordinate system, the Sigma coordinate system was evaluated to have no irrationalities in data analysis with 5% of error. As a result of the analysis, the tidal residual flow displayed the flow pattern of sagging in the both ends in the main waterway direction of dry season. During flood season, it was confirmed that the tidal residual flow was vertical 2-layer flow. As a result of the total mass flux, the ebb properties of 359 cm/s and 261 cm/s were observed during dry and flood season, respectively. The total mass flux was moving the intertidal region between Youngjong-do and Ganghwa-do.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.3
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• pp.247-256
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• 2012

Stable carbon isotope ratio of oil components are known to be unaffected by weathering processes and thus has been widely used to determine the origin of spilled oil. In this study, molecular index and composition of stable carbon isotope in 15 crude oils and petroleum product were analyzed and used as oil fingerprints to determine the discriminating power of each fingerprinting method among target crude oils. Through the fingerprints of alkane distribution only Bintulu and B-C(1%) were distinguishable from other crude oils. The pristane/phytane ratio can classify the crude oils into three groups but differentiation of crude oils within a group was impossible using the ratio. The crude oils of A.L., A.S.L., Foroozan and B-C(1%) were differentiated from the other oils using PAH source recognition indexes of C2D/C2P and C3D/C3P. The usage of 4-mD/1-mD and 2/3-mD/1-mD ratio was able to distinguish A.S.L., Bintulu and Oman from the other crude oils. However the PAH source recognition ratios in the other crude oils were similar and thus they were impractical to be used for source identification among the target crude oils. Stable carbon isotope ratios of alkanes were able to uniquely specify each crude oil in the plot of ${\delta}^{13}C_{C21}$ and ${\delta}^{13}C_{C25}$ except A.L., A.M., Qatar-Marine, B-C(1%). The oil fingerprinting method using stable carbon isotope ratios of individual alkane compounds showed more discriminating power among the target crude oils than the conventional source recognition indexes of PAHs or alkanes.

• Journal of the Korean Society of Safety
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• v.7 no.2
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• pp.63-70
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• 1992

The aim of this research is to obtain a basic quantitative understanding of the effect of a noncondensable gas on the absorption of water vapor by a $H_2O$ / LiBr combination with n-octanol as the surfactant. Nonflowing aqueous solutions of LiBr (40,45,50 mass％) were exposed to saturated water vapor following the addition of an n-octanol sufactant (0.01 and 0.6 mass％). A small amount of a noncondensable gas (air) was allowed into the absorber (0.03 volume％) and its effect was analyzed by measuring the amount of water vapor absorbed. This study will aid to predict the performance of heat pump and safety operating condition when the noncondensable gas is not allowed in the absorber The results indicate that, in the presence of small amounts of a noncondensable gas, vapor absorption enhancement ratios are less than half o( those obtained under the same experimental conditions when a noncondensable gas is not present (1). The presence of a noncondensable gas causes the partial vapor pressure of air to increase at the vapor / liquid interface, which results in an instability of vapor absorption rate nd. hence, in an inhibition of interfacial disturbance.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.970-976
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• 2011

Strip tiller equipment was developed to reduce soil erosion in the slope land for highland agricultural area. The equipment consisted of 4 rows strip tillage device and fertilizer applicator. The field was tilled in 10 cm width and in 10 cm depth by the equipment, of which tilled surface was 16.7% of full-width tillage. The working time and fuel consumption of the equipment were $3.8hours\;ha^{-1}$ and $24.4L\;ha^{-1}$ respectively, which were 59% and 74% less than those of the conventional tillage. Fertilizer efficiency of the equipment in cultivation of Chinese cabbage was 1.7, 1.6 and 1.5 times higher in nitrate, phosphorous and potassium respectively, than conventional tillage. When the equipment was used after covering of rye residue, the quantity of runoff was 49~67% lower than the conventional tillage. And the quantity of soil loss were 1.3 and $0.2Mg\;ha^{-1}$ at right after and 30 days after planting of Chinese cabbage respectively, while 11.5 and $4.1Mg\;ha^{-1}$ in conventional tillage. In conclusion, the strip tillage equipment developed in this study can be applicable to slope land, so that soil loss of 90% can be reduced.

• Journal of Korean Society of Forest Science
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• v.84 no.4
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• pp.465-478
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• 1995

The objective of this study was to investigate the impacts of large-scale timber harvesting on the environment of a mature hardwood forest. To achieve the objective, the effects of harvesting on forest environmental factors were analyzed quantitatively using the field data measured in the study sites of Seoul National University Research Forests [(Mt.) Paekunsan] for two years(1993-1994) following timber harvesting. The field data include information on vegetation, soil mesofauna, physicochemical characteristics of soil, surface water runoff, water quality in the stream, and hillslope erosion. For comparison, field data for each environmental factor were collected in forest areas disturbed by logging and undisturbed, separately. The results of this study were as follows : The diversity of vegetational species increased in the harvested sites. However, the similarity index value of species between harvested and non-harvested sites was close to each other. Soil bulk density and soil hardness were increased after timber harvesting, respectively. The level of organic matter, total-N, avail $P_2O_5$, CEC($K^+$, $Na^+$, $Ca^{{+}{+}}$, $Mg^{{+}{+}}$) in the harvested area were found decreased. While the population of Colembola spp., and Acari spp. among soil mesofauna in harvested sites increased by two to seven times compared to those of non-harvested sites during the first year, the rates of increment decreased in the second year. However, those members of soil mesofauna in harvested sites were still higher than those of non-harvested sites in the second year. The results of statistical analysis using the stepwise regression method indicated that the diversity of soil mesofauna were significantly affected by soil moisture, soil bulk density, $Mg^{{+}{+}}$, CEC, and soil temperature at soil depth of 5(0~10)cm in the order of importance. The amount of surface water runoff on harvested sites was larger than that of non-harvested sites by 28% in the first year and 24.5% in the second year after timber harvesting. The level of BOD, COD, and pH in the stream water on the harvested sites reached at the level of the domestic use for drinking in the first and second year after timber harvesting. Such heavy metals as Cd, Pb, Cu, and organic P were not found. Moreover, the level of eight factors of domestic use for drinking water designated by the Ministry of Health and Welfare of Korea were within the level of the first class in the quality of drinking water standard. The study also showed that the amount of hillslope erosion in harvested sites was 4.77 ton/ha/yr in the first year after timber harvesting. In the second year, the amount decreased rapidly to 1.0 ton/ha/yr. The impact of logging on hillslope erosion in the harvested sites was larger than that in non-harvested sites by seven times in the first year and two times in the second year. The above results indicate that the large-scale timber harvesting cause significant changes in the environmental factors. However, the results are based on only two-year field observation. We should take more field observation and analyses to increase understandings on the impacts of timber harvesting on environmental changes. With the understandings, we might be able to improve the technology of timber harvesting operations to reduce the environmental impacts of large-scale timber harvesting.

• Korean Journal of Heritage: History & Science
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• v.37
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• pp.371-405
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• 2004

International circulation of cultural assets involves numerous countries thereby making an approach based on international law essential to resolving this problem. Since the end of the $2^{nd}$ World War, as the value of cultural assets evolved from material value to moral and ethical values, with emphasis on establishing national identities, newly independent nations and former colonial states took issue with ownership of cultural assets which led to the need for international cooperation and statutory provisions for the return of cultural assets. UNESCO's 1954 "Convention for the Protection of Cultural Property in the Event of Armed Conflict" as preparatory measures for the protection of cultural assets, the 1970 "Convention on the Means of Prohibiting and Preventing the Illicit Import and Transfer of Ownership of Cultural Property" to regulate transfer of cultural assets, and the 1995 "Unidroit Convention on Stolen or Illegally Exported Cultural Objects" which required the return of illegally acquired cultural property are examples of international agreements established on illegal transfers of cultural assets. In addition, the UN agency UNESCO established the Division of Cultural Heritage to oversee cultural assets related matters, and the UN since its 1973 resolution 3187, has continued to demonstrate interest in protection of cultural assets. The resolution 3187 affirms the return of cultural assets to the country of origin, advises on preventing illegal transfers of works of art and cultural assets, advises cataloguing cultural assets within the respective countries and, conclusively, recommends becoming a member of UNESCO, composing a forum for international cooperation. Differences in defining cultural assets pose a limitation on international agreements. While the 1954 Convention states that cultural assets are not limited to movable property and includes immovable property, the 1970 Convention's objective of 'Prohibiting and preventing the illicit import, export and transfer of ownership of cultural property' effectively limits the subject to tangible movable cultural property. The 1995 Convention also has tangible movable cultural property as its subject. On this point, the two conventions demonstrate distinction from the 1954 Convention and the 1972 Convention that focuses on immovable cultural property and natural property. The disparity in defining cultural property is due to the object and purpose of the convention and does not reflect an inherent divergence. In the case of Korea, beginning with the 1866 French invasion, 36 years of Japanese colonial rule, military rule and period of economic development caused outflow of numerous cultural assets to foreign countries. Of course, it is neither possible nor necessary to have all of these cultural properties returned, but among those that have significant value in establishing cultural and historical identity or those that have been taken symbolically as a demonstration of occupational rule can cause issues in their return. In these cases, the 1954 Convention and the ratification of the first legislation must be actively considered. In the return of cultural property, if the illicit acquisition is the core issue, it is a simple matter of following the international accords, while if it rises to the level of diplomatic discussions, it will become a political issue. In that case, the country requesting the return must convince the counterpart country. Realizing a response to the earnest need for preventing illicit trading of cultural assets will require extensive national and civic societal efforts in the East Asian area to overcome its current deficiencies. The most effective way to prevent illicit trading of cultural property is rapid circulation of information between Interpol member countries, which will require development of an internet based communication system as well as more effective deployment of legislation to prevent trading of illicitly acquired cultural property, subscription to international conventions and cataloguing collections.

• Journal of Animal Environmental Science
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• v.6 no.3
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• pp.175-184
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• 2000

A lab-scale MF membrane reactor was installed to investigate the membrane permeability, characteristics of membrane fouling at each conditions, and quality of permeate (liquid livestock manure) in the separation of solid-matters using membrane. Experiment was divided three filtration type such as follows; continuous filtration, gravity filtration, and intermittent filtration. As a result of experiment, flux 1 LMH was maintained for 7days, and trans-membrane pressure(TMP) was increased gradually under 10cmHg, but it was increased immediately after 10cmHg, respectively. However, the flux was increased, the Tmax was decreased exponential more and more. During the pure-flux test, most of the fouling of membrane was reversible. At the gravity filtration, permeate could be obtained as 1.75 LMH for 3.5days without any other electronic pressure. As an investigation of membrane surface, this study could be decided that the reason of fouling at the lower flux (Run 1 and 2) was attached matters in membrane surface, but at the higher flux (Run 4-6) was concentration polarization.