• Economic and Environmental Geology
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• v.56 no.4
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• pp.409-419
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• 2023

Acid mine drainage(AMD) treatment is classified as both passive and active treatment. During the treatment, about 5,000 tons of neutralization sludge is generated as a by-product per year in Korea. This study was conducted to evaluate the characteristics of sludge generated from physico·chemical treatment processes as an active treatment from 5 different sources (D, H, S, T, Y) and the possibility of the sludges being recycled. The sludges have a pH range of 5.86 ~ pH 7.89, and a water content range of 51% ~ 82%. Most of particle sizes were less than 25 ㎛. In analysis of inorganic elements, the concentration of Al, Fe, and Mn were between 1,189 mg/kg ~ 129,344 mg/kg, 106,132 mg/kg ~ 338,011 mg/kg, and 3,472 mg/kg ~ 11,743 mg/kg, respectively. The concentration of As and Zn in sludge-T, Cd in sludge-D, Ni in sludge-H, Zn in sludge-S, and Cd in sludge-Y exceeded the soil contamination standards of Korea. The results from 2 separate kinds of leaching test, the Korea Standard Leaching Test(KSLT) and Toxicity Characteristic Leaching Procedure(TCLP), showed that all the sludges met the Korea groundwater standards. From the XRD and SEM-EDS analysis, the peaks of calcite and quartz were found in the sludges. The sludge also had a high proportion of Fe and O, and the majority of the composition was amorphous iron hydroxide.

• Journal of Korea Water Resources Association
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• v.55 no.10
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• pp.723-736
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• 2022

In this study, monthly precipitation forecasting models that can predict up to 12 months in advance were constructed for the Geum River basin, and two statistical techniques, multiple linear regression (MLR) and artificial neural network (ANN), were applied to the model construction. As predictor candidates, a total of 47 climate indices were used, including 39 global climate patterns provided by the National Oceanic and Atmospheric Administration (NOAA) and 8 meteorological factors for the basin. Forecast models were constructed by using climate indices with high correlation by analyzing the teleconnection between the monthly precipitation and each climate index for the past 40 years based on the forecast month. In the goodness-of-fit test results for the average value of forecasts of each month for 1991 to 2021, the MLR models showed -3.3 to -0.1% for the percent bias (PBIAS), 0.45 to 0.50 for the Nash-Sutcliffe efficiency (NSE), and 0.69 to 0.70 for the Pearson correlation coefficient (r), whereas, the ANN models showed PBIAS -5.0~+0.5%, NSE 0.35~0.47, and r 0.64~0.70. The mean values predicted by the MLR models were found to be closer to the observation than the ANN models. The probability of including observations within the forecast range for each month was 57.5 to 83.6% (average 72.9%) for the MLR models, and 71.5 to 88.7% (average 81.1%) for the ANN models, indicating that the ANN models showed better results. The tercile probability by month was 25.9 to 41.9% (average 34.6%) for the MLR models, and 30.3 to 39.1% (average 34.7%) for the ANN models. Both models showed long-term predictability of monthly precipitation with an average of 33.3% or more in tercile probability. In conclusion, the difference in predictability between the two models was found to be relatively small. However, when judging from the hit rate for the prediction range or the tercile probability, the monthly deviation for predictability was found to be relatively small for the ANN models.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.5
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• pp.430-436
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• 2015

Numerical air quality forecasting suffers from the large uncertainties of input data including emissions, boundary conditions, earth surface properties. Data assimilation has been widely used in the field of weather forecasting as a way to reduce the forecasting errors stemming from the uncertainties of input data. The present study aims at evaluating the effect of input data on the air quality forecasting results in Korea when data assimilation was invoked to generate the initial concentrations. The forecasting time was set to 36 hour and the emissions and initial conditions were chosen as tested input parameters. The air quality forecast model for Korea consisting of WRF and CMAQ was implemented for the test and the chosen test period ranged from November $2^{nd}$ to December $1^{st}$ of 2014. Halving the emission in China reduces the forecasted peak value of $PM_{10}$ and $SO_2$ in Seoul as much as 30% and 35% respectively due to the transport from China for the no-data assimilation case. As data assimilation was applied, halving the emissions in China has a negligible effect on air pollutant concentrations including $PM_{10}$ and $SO_2$ in Seoul. The emissions in Korea still maintain an effect on the forecasted air pollutant concentrations even after the data assimilation is applied. These emission sensitivity tests along with the initial condition sensitivity tests demonstrated that initial concentrations generated by data assimilation using field observation may minimize propagation of errors due to emission uncertainties in China. And the initial concentrations in China is more important than those in Korea for long-range transported air pollutants such as $PM_{10}$ and $SO_2$. And accurate estimation of the emissions in Korea are still necessary for further improvement of air quality forecasting in Korea even after the data assimilation is applied.

• Journal of Korea Water Resources Association
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• v.37 no.3
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• pp.173-184
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• 2004

The objective of this study is to examine the usefulness of climate model simulations (GCM) in Korea water resource management. The methods are based on probabilistic measures of the effectiveness of GCM simulations of an indicator variable for discriminating high versus low regional observations of a target variable. The formulation uses the significance probability of the Kolmogorov-Smirnov test for detecting differences between two variables. AMIP-II(Atmospheric Model Intercomparison Project-II) type GCM simulation done by ECMWF(European Centre for Medium-Range Weather Forecasts) was used for indicator variable and observed mean average precipitation(MAP) values on 7 major river basins were used as target variable. Monte Carlo simulation is used to establish the significance of the estimator values. The results show that GCM simulations done by ECMWF are skillful in discriminating the high from the low of the observed MAP for wet season in all seven basins of Korea, but not enough for dry season.

• Journal of Environmental Science International
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• v.29 no.12
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• pp.1239-1248
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• 2020

This study performed to conduct a test to increase the amount of appropriate organic matter input to organic upland soil, soil fertility, and its effect on the chemical changes and yield of corn in soil due to organic use. The pH level of the T1, T5, and T6 treatment zones where livestock excreta was used was raised to 6.0-6.5, the optimal range of the soil in Korea, and it was confirmed that the pH value was appropriate. Electrical Conductivity (EC), organic content (OM), and total nitrogen (T-N) were also identified as a trend of continuous increase. The quantity of corn gradually increased from 74.1% to 96.4% over the four-year period with the use of organic materials compared to the beginning of the test, and the utilization efficiency of nitrogen has also increased. The results of the study were found to have been able to examine the increase in quantity and changes in soil chemistry through crop cultivation using organic materials such as natural materials, green manure crops, and livestock manure compost, and it is also believed that the changes due to various factors such as soil environment, soil microbes, and climate conditions need to be made through continuous research.

• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.320-326
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• 2015

Mechanical properties of woods are easily affected by the differences of site environment such as soil and climate changes. In this study, the relationship between mechanical properties and growth factors for Cryptomeria japonica stands in Jeollanam-do Province, Gyeongsangnam-do Province and Je-ju island was analyzed. From these plot data, bending strength, compressive strength, and shear strength were analyzed by Duncan's new multiple range test. The results of Duncan's new multiple range test analysis indicated that bending strength, compression strength, and shear strength were positively related to tree mean height, and stem number per ha, respectively, while they were inversely proportional to DBH (diameter at breast height), elevation, and soil drainage. As a result of this study, there are high correlations between mechanical properties of wood and stand characteristics of Cryptomeria japonica by the region, this findings are very useful to apply the silvicultural treatment system to produce high quality timber as a basic data on this species (distributed in southern region of Korea).

• Journal of Ecology and Environment
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• v.44 no.3
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• pp.162-177
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• 2020

Background: Ecologists have achieved much progress in the study of mechanisms that maintain species coexistence and diversity. In this paper, we reviewed a wide range of past research related to these topics, focusing on five theoretical bodies: (1) coexistence by niche differentiation, (2) coexistence without niche differentiation, (3) coexistence along environmental stress gradients, (4) coexistence under non-equilibrium versus equilibrium conditions, and (5) modern perspectives. Results: From the review, we identified that there are few models that can be generally and confidently applicable to different ecological systems. This problem arises mainly because most theories have not been substantiated by enough empirical research based on field data to test various coexistence hypotheses at different spatial scales. We also found that little is still known about the mechanisms of species coexistence under harsh environmental conditions. This is because most previous models treat disturbance as a key factor shaping community structure, but they do not explicitly deal with stressful systems with non-lethal conditions. We evaluated the mainstream ideas of niche differentiation and stochasticity for the coexistence of plant species across salt marsh creeks in southwestern Denmark. The results showed that diversity indices, such as Shannon-Wiener diversity, richness, and evenness, decreased with increasing surface elevation and increased with increasing niche overlap and niche breadth. The two niche parameters linearly decreased with increasing elevation. These findings imply a substantial influence of an equalizing mechanism that reduces differences in relative fitness among species in the highly stressful environments of the marsh. We propose that species evenness increases under very harsh conditions if the associated stress is not lethal. Finally, we present a conceptual model of patterns related to the level of environmental stress and niche characteristics along a microhabitat gradient (i.e., surface elevation). Conclusions: The ecology of stressful systems with non-lethal conditions will be increasingly important as ongoing global-scale climate change extends the period of chronic stresses that are not necessarily fatal to inhabiting plants. We recommend that more ecologists continue this line of research.

• Journal of Korean Society of Transportation
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• v.33 no.1
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• pp.90-99
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• 2015

The climate of Korea has clear rainy and dry season due to seasonal wind. In general, The rainy season in Korea is from early summer through to early fall. And precipitation accounted for more than half of the total annual rainfall in this period. This study is aiming to analysis of variation in saturation flow rate at signalized intersection during rainfall. The range of spatial is urban signalized intersections in Seoul and temporal is rainfall or ideal condition in daylight. Traffic data are collected through CCTV of Seoul Metropolitan Police Agency, and on-site video recordings directly. Weather condition data are collected from the Korea Meteorological Administration. In addition, the value of saturation headway and saturation flow rate, in rainfall condition, are derived through video frame analysis. As a results of analysis, decrease of saturation flow rate and increase of saturation headway during rainfall were confirmed by comparison with non-rainfall. The higher rainfall rate is, the more decreased saturation flow rate at the intersections. Rainfall rate is divided three area by the results of statistical test, and saturation flow rate decrease 7%, 17%, 21%, respectively.

• Journal of the Korean Institute of Landscape Architecture
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• v.46 no.4
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• pp.76-83
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• 2018

The purpose of this study is to analyze people who applied for and passed engineer landscape architecture examination that had been conducted from 2007 to 2016, the test frequency and trends by the question types in the landscape structure construction and management area, and the test tendencies and features by question types, and thereby to find the test trends for landscape structure construction and management in engineer landscape architecture examination. the analysis results are presented as follows: The people who applied for and passed engineer landscape architecture examinations that had been conducted from 2007 to 2016 were analyzed. as a result, the numbers of applicants and those who passed the examination have been on the decrease from 2011 and from 2012, respectively. the 10-year average rate of successful applicants for engineer landscape architecture examination was 11.2%. The test frequency and trends by the question types in the landscape structure construction area, and the test tendencies and features were analyzed. as a result, based on the key words in the seven categories (construction plan & process management, landscape materials, landscape planting foundation, work classification based construction, landscape estimation, basic structural mechanics, and survey), the questions about work classification based construction accounted for the largest, or 25.2%, and the questions about landscape planting foundation accounted for 3.3%. therefore, landscape planting foundation had lower test frequency and was less important than other categories. The test frequency and trends by the question types in the landscape management area, and the test tendencies and features were analyzed. as a result, based on the key words in the nine categories (operation and use & maintenance, pruning management, fertilization management, weed management, irrigation and drainage management, wintering management, pest management, and lawn management, and landscape facility management), the questions about operation and use & maintenance accounted for the largest, or 37.2%, and the numbers of the questions about fertilization management and irrigation & drainage management and of the questions about waterscape facility of landscape facility management have been on the increase from 2011 and from 2015, respectively. According to the analysis on the test tendencies for landscape structure construction and management areas in the examination there have been questions in a wide range and variety of categories. in terms of the landscape structure construction area, the frequency of questions in work classification based construction, landscape materials, and excellent quality in terms of the landscape management area, the frequency of questions in fertilization management, irrigation & drainage management, and waterscape facility of landscape facility management tends to increase because of environmental factors like climate change.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.4
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• pp.69-85
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• 2014

Carbon stocks of NFI plots can be accurately estimated using field survey information. However, an accurate estimation of carbon stocks in other unsurveyed sites is very difficult. In order to fill this gap, various spatial information can be used as an ancillary data. In South Korea, there is the 1:5,000 forest type map that was produced by digital air-photo interpretation and field survey. Because this map contains very detailed forest information, it can be used as the high-quality spatial data for estimating carbon stocks. In this study, we compared three upscaling methods based on the 1:5,000 forest type map and 5th national forest inventory data. Map algebra(method 1), RK(Regression Kriging)(method 2), and GWR(Geographically Weighted Regression)(method 3) were applied to estimate forest carbon stock in Chungcheong-nam Do and Daejeon metropolitan city. The range of carbon stocks from method 2(1.39~138.80 tonC/ha) and method 3(1.28~149.98 tonC/ha) were more similar to that of previous method(1.56~156.40 tonC/ha) than that of method 1(0.00~93.37 tonC/ha). This result shows that RK and GWR considering spatial autocorrelation can show spatial heterogeneity of carbon stocks. We carried out paired t-test for carbon stock data using 186 sample points to assess estimation accuracy. As a result, the average carbon stocks of method 2 and field survey method were not significantly different at p=0.05 using paired t-test. And the result of method 2 showed the lowest RMSE. Therefore regression kriging method is useful to consider spatial variations of carbon stocks distribution in rugged terrain and complex forest stand.