• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.11-16
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• 2011

This study was conducted to identify the morphological characteristics and variations level by site environment of native bermudagrass (Cynodon spp.) from costal and island region in South Korea. Soil chemical properties and morphological characteristics were investigated. There were significant differences in plant height, leaf width, leaf length, cotton on leaf blade, stolon, and number of seed per spike depending on where they were collected from natural habitat. We have discovered a variety of variation among the investigated traits in Korean native bermudagrass ecotypes. There were broad leaf and fine leaf types of native bermudgarass in S. Korea. Adaptability was in very high on inadequate environment in bermudagrass with broad leaf types, it has also been suggested that management worth in terms of use. These results may provide basic information for bermudagrass breeding development and the collected types during this investigation would be worth being preserved as genetic resources for further breeding purposes.

• The Korean Journal of Pesticide Science
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• v.15 no.2
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• pp.97-103
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• 2011

The residual patterns of azoxystrobin and cyenopyrafen were investigated to compare the differences between rainshield and plastic house conditions of the grapes. Initial residue concentrations of azoxystrobin were $0.54\;mg{\cdot}kg^{-1}$ under rainshield condition and $0.9\;mg{\cdot}kg^{-1}$ under plastic house condition. And cyenopyrafen was 0.55 and $0.64\;mg{\cdot}kg^{-1}$ respectively. Biological half-life of azoxystrobin was calculated as 13.28 days under rainshield and 15.58 days under plastic house condition. And cyneopyrafen was 7.99 and 12.65 days, respectively. In comparison with two different cultivation conditions, pesticides in/on the grape were decomposed more faster under plastic house than rain shield conditions.

• Geophysics and Geophysical Exploration
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• v.17 no.3
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• pp.163-170
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• 2014

Development of a modeling technique for accurately interpreting electromagnetic (EM) data is increasingly required. We introduce finite difference (FD) and finite-element (FE) methods for three-dimensional (3D) frequency-domain EM modeling. In the controlled-source EM methods, formulating the governing equations into a secondary electric field enables us to avoid a singularity problem at the source point. The secondary electric field is discretized using the FD or FE methods for the model region. We represent iterative and direct methods to solve the system of equations resulting from the FD or FE schemes. By applying the static divergence correction in the iterative method, the rate of convergence is dramatically improved, and it is particularly useful to compute a model including surface topography in the FD method. Finally, as an example of an airborne EM survey, we present 3D modeling using the FD method.

• Journal of Korean Society of Transportation
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• v.26 no.5
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• pp.131-141
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• 2008

The objective of this study is to propose methods for determining optimal representative value and the optimal size of historical data for reliable travel time forecasting. We selected values with the smallest mean of forecasting errors as the optimal representative value of travel time pattern data. The optimal size of historical data used was determined using the CVMSE(Cross Validated Mean Square Error) method. According to the results of applying the methods to point vehicle detection data of Korea Highway Corporation, the optimal representative value were analyzed to be median. Second, it was analyzed that 60 days' data is the optimal size of historical data usedfor travel time forecasting.

• The Journal of the Petrological Society of Korea
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• v.23 no.2
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• pp.145-152
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• 2014

Geological heritages can be defined conveniently as geological records worthy of conservation, and are represented in most cases by geological outcrops. So survey and evaluation of geologic outcrops are necessary for better conservation of geological heritages. As a measure to prevent potential destruction of geological heritages from various development projects, I propose construction of database based on survey and evaluation forms of geological outcrop, which can also be used for environmental impact assessment. The geological survey form consists of survey area, category, subcategory, location, dimension, geologic features, photo, description, and investigator. The evaluation form consists of evaluation category, detailed evaluation, comprehensive evaluation, and evaluation grade. The evaluation category is divided into academic aspect, education effect and landscape. The detailed evaluation items for academic aspects and education effect are representativeness, rarity, diversity and typicality, while those for geomorphology and landscape are peculiarity, aesthetics and naturalness. The evaluation grades are divided into five, where the first grade means a must of conservation.

• Journal of the Korean Geographical Society
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• v.45 no.3
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• pp.414-429
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• 2010

With regard to Ieodo, South Korea and China argue that Ieodo belongs to their territory respectively, considering its history. However, both parties haven't suggested concrete evidence to support their argument. Even if they suggest corroborative facts, they are distorted or exaggerated like myth. Therefore, it is important by what side primitive title and effective control are exercised in settling the problem of Ieodo. The issue was to suggest coherence logic by finding concrete geographical facts in the East China Seat the time of applying a method of boundary decision followed by the marine act, namely principle of median line and principle of equidistance. China has argued that China should occupy most of continental shelf in the East China Sea on the basis of silt, a deposit of the continent. However, the base of the East China Sea is a part of Eurasian Plate. In addition, a geographical contribution to formation of the continent shelf by the Korean Peninsula is equal to the Chinese Continent. Ieodo is 'Island of mythos' in China, but is 'Island of legend' suggested by concrete facts in South Korea. Therefore, its cultural titile and primitive title are belonged to South Korea, before its historical title.

• Korean Chemical Engineering Research
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• v.47 no.2
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• pp.248-257
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• 2009

In this paper, human exposure and risk of environmental pollutants were predicted using an emission assessment model and multimedia fate model. Eight environmental pollutants, acetaldehyde, acrylonitrile, aniline, benzene, carbon tetrachloride, dichloromethane, formaldehyde and vinyl chloride, were selected for the risk assessment in an urban and industrial area in Korea. The emission rate of target pollutants were estimated after considering a variety of point and non-point emission sources including geographical information. A spatially refined multimedia fate model was applied to predict the environmental concentration and fate of pollutants. Hazard data of target materials were obtained from the IRIS(Integrated Risk Information System) database. Using the modeling results with hazard data, the human risks were assessed. Modeling results demonstrate that the considerable risks were observed for several pollutants.

• Atmosphere
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• v.16 no.4
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• pp.359-370
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• 2006

Terrain height variance spectra for the Korean mountain region are calculated in order to determine an adequate grid size required to resolve terrain forcing on mesoscale model simulation. One-dimensional spectral analysis is applied to specifically the central-eastern part of the Korean mountain region, where topographical-scale forcing has an important effect on mesoscale atmospheric flow. It is found that the terrain height variance spectra in this mountain region has a wavelength dependence with the power law exponents of 1.5 at the wavelength near 30 km, but this dependence is steeply changed to 2.5 at the wavelength less than 30 km. For the adequate horizontal grid size selection on mesoscale simulation two-dimensional terrain height spectral analysis is also performed. There is no directionality within 50% of spectral energy region, so one-dimensional spectral analysis can be reasonably applied to the Korea Peninsula. According to the spectral analysis of terrain height variance, the finer grid size which is higher than 6 km is required to resolve a 90% of terrain variance in this region. Numerical simulation using WRF (Weather Research and Forecasting Model) was performed to evaluate the effect of different terrain resolution in accordance with the result of spectral analysis. The simulated results were quantitatively compared to observations and there was a significant improvement in the wind prediction across the mountain region as the grid space decreased from 18 km to 2 km. The results will provide useful guidance of grid size selection on mesoscale topographical simulation over the Korean mountain region.

• Atmosphere
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• v.22 no.2
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• pp.233-243
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• 2012

The Barnes scheme is used in Digital Forecast System (DFS) of the Korea Meteorological Administration (KMA) for real-time analysis. This scheme is an objective analysis scheme with a distance-dependent weighted average. It has been widely used for mesoscale analyses in limited geographic areas. The isotropic Gaussian weight function with a constant effective radius might not be suitable for certain conditions. In particular, the analysis error can be increased for stations located near mountains. The terrain of South Korea is covered with mountains and wide plains that are between successive mountain ranges. Thus, it is needed to consider the terrain effect with the information of elevations for each station. In order to improve the accuracy of the temperature objective analysis, we modified the weight function which is dependent on a distance and elevation in the Barnes scheme. We compared the results from the Barnes scheme used in the DFS (referred to CTL) with the new scheme (referred to EXP) during a year of 2009 in this study. The analysis error of the temperature field was verified by the root-mean-square-error (RMSE), mean error (ME), and Priestley skill score (PSS) at the DFS observation stations which is not used in objective analysis. The verification result shows that the RMSE and ME values are 1.68 and -0.41 in CTL and 1.42 and -0.16 in EXP, respectively. In aspect of spatial verification, we found that the RSME and ME values of EXP decreased in the vicinity of Jirisan (Mt. Jiri) and Taebaek Mountains. This indicates that the new scheme performed better in temperature verification during the year 2009 than the previous scheme.

• Atmosphere
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• v.23 no.4
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• pp.501-511
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• 2013

In this study, we estimate the background concentration of black carbon (BC) mass concentration measured at Gosan Climate Observatory from January 2008 to December 2011 by applying six methods: (1) Mean and Median (2) Trimmed mean method deployed in Interagency Monitoring of Protected Visual Environments (IMPROVE) network program (hereafter, IMPROVE method), (3) Concentration-frequency distribution analysis method, (4) Advanced Global Atmospheric Gases Experiment (AGAGE) method (hereafter, AGAGE method), (5) Kaufman et al. (2001) method (hereafter, Kaufman method), and (6) Airmass sector analysis. The background concentration of BC mass concentrations is estimated to be about 400~900 ng $m^{-3}$, but each method shows a large difference. The estimated background concentration, in general, is arranged in the order of: mean > IMPROVE method > median > Kaufman method > concentration-frequency distribution analysis method > AGAGE method. The background concentration estimated by the airmass sector analysis is found to be about 550 ng $m^{-3}$ which is lower than those estimated by other methods. When we apply the same analytical period (i.e., 4-day and 6-day) to both AGAGE and Kaufman methods, the estimated background concentrations are quite similar. However, further researches on the development of statistical method for estimating background concentration for various gas-phase and particulate pollutants under different environment are needed.