• Journal of Radiation Protection and Research
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• v.40 no.2
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• pp.87-91
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• 2015

We have employed X-ray photoelectron spectroscopy (XPS) technique to examine the combined effects of low-energy electron (LEE) irradiation and $Fe^{3+}$ ion on DNA damage. pBR322 plasmid DNA extracted from E. coli ER2420 was used for preparing DNA-$Fe^{3+}$ sample. The C1s XPS spectra were scanned for LEE-irradiated and LEE-unirradiated samples and then curve-fitted. For the samples with LEE irradiation only or with Fe ion only, no significant changes from pure DNA samples were observed - a single effect of either $Fe^{3+}$ ion or LEE irradiation did not cause a significant damage. However, when these two components were combined, the DNA damage was increased quite significantly, compared to the sum of DNA damages caused by $Fe^{3+}$ ion and by LEE irradiation independently. This observation is consistent with our previous results [Radiat. Res. 177, 775 (2012)] which was done using gel-electrophoresis technique. Partial interpretation of the observed spectrum peaks was also attempted.

• Journal of the Korean Society for Railway
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• v.12 no.2
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• pp.190-198
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• 2009

This study shows the developing process of the risk assessment models for railway casualty accidents. To evaluate the risks of these accidents, the hazardous events and the hazardous factors were identified by the review of the accident history and engineering interpretation of the accident behavior. The frequency of each hazardous event was evaluated from the historical accident data and structured expert judgments by using the Fault Tree Analysis (FTA) technique. In addition, to assess the severity of each hazardous event, the ETA (Event Tree Analysis) technique and other safety techniques were applied. The risk assessment models developed can be effectively utilized in defining the risk reduction measures in connection with the option analysis.

• Applied Microscopy
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• v.44 no.4
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• pp.138-143
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• 2014

Transmission electron microscope (TEM) is an excellent tool for studying the structure and properties of nanostructured materials. As the development of $C_s$-corrected TEM, the direct analysis of atomic structures of nanostructured materials can be performed in the high-resolution transmission electron microscopy (HRTEM). Especially, fast Fourier transform (FFT) technique in image processing is very useful way to determine the crystal structure of HRTEM images in reciprocal space. To apply FFT technique in HRTEM analysis in more reasonable and friendly manner, we made a new circular region of interest (C-ROI) FFT script and tested it for several HRTEM analysis. Consequentially, it was proved that the new FFT application shows more quantitative and clearer results than conventional FFT script by removing the streaky artifacts in FFT pattern images. Finally, it is expected that the new FFT script gives great advantages for quantitative interpretation of HRTEM images of many nanostructured materials.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.1
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• pp.59-64
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• 2002

A FEM model of the remote-field eddy current effect is presented for zirconium-2.5 percent niobium(Zr-2.5%Nb) nuclear reactor pressure tubes to demonstrate the important electromagnetic field phenomena. This model is applied to evaluate the optimal operating frequency and detector position. There are many ambiguous experimental results connected with this technique. Finite element calculations can be used in the interpretation of these experimental results even though the electromagnetic fields measured in the remote-field technique are very small.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.3
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• pp.181-193
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• 2010

The paper presents an alternative way to classical stereocorrelation. First, 2D image processing of random patterns is described. Sub-pixel displacements are determined using phase analysis. Then distortion evaluation is presented. The distortion is identified without any assumption on the lens model because of the use of a grid technique approach. Last, shape measurement and shape variation is caught by fringe projection. Analysis is based on two pin-hole assumptions for the video-projector and the camera. Then, fringe projection is coupled to in-plane displacement to give rise to 3D measurement set-up. Metrological characterization shows a resolution comparable to classical (stereo) correlation technique ($1/100^{th}$ pixel). Spatial resolution seems to be an advantage of the method, because of the use of temporal phase stepping (shape measurement, 1 pixel) and windowed Fourier transform (in plane displacements measurement, 9 pixels). Two examples are given. First one is the study of skin properties; second one is a study on leather fabric. In both cases, results are convincing, and have been exploited to give mechanical interpretation.

• Journal of Environmental Science International
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• v.28 no.1
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• pp.125-135
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• 2019

For the purposes of enhancing usability of Numerical Weather Prediction (NWP), the quantitative precipitation prediction scheme by machine learning has been proposed. In this study, heavy rainfall was corrected for by utilizing rainfall predictors from LENS and Radar from 2017 to 2018, as well as machine learning tools LightGBM and XGBoost. The results were analyzed using Mean Absolute Error (MAE), Normalized Peak Error (NPE), and Peak Timing Error (PTE) for rainfall corrected through machine learning. Machine learning results (i.e. using LightGBM and XGBoost) showed improvements in the overall correction of rainfall and maximum rainfall compared to LENS. For example, the MAE of case 5 was found to be 24.252 using LENS, 11.564 using LightGBM, and 11.693 using XGBoost, showing excellent error improvement in machine learning results. This rainfall correction technique can provide hydrologically meaningful rainfall information such as predictions of flooding. Future research on the interpretation of various hydrologic processes using machine learning is necessary.

• Geomechanics and Engineering
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• v.36 no.3
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• pp.247-258
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• 2024

Tailings are waste materials of mining operations, consisting of a mixture of clay, silt, sand with a high content of unrecoverable metals, process water, and chemical reagents. They are usually discharged as slurry into the storage area retained by dams or earth embankments. Poor knowledge of the hydro-mechanical behaviour of tailings has often resulted in a high rate of failures in which static liquefaction has been widely recognized as one of the major causes of dam collapse. Many studies have dealt with the static liquefaction of coarse soils in saturated conditions. This research provides an extension to the case of silty tailings in unsaturated conditions. The static liquefaction resistance was evaluated in terms of stress-strain behavior by means of monotonic triaxial tests. Its dependency on the preparation method, the volumetric water content, the void ratio, and the degree of saturation was studied and compared with literature data. The static liquefaction response was proved to be dependent mainly on the preparation technique and degree of saturation that, in turn, controls the excess of pore pressure whose leading role is investigated by means of the relationship between the -B Skempton parameter and the degree of saturation. A preliminary interpretation of the static liquefaction response of Stava tailings is also provided within the Critical State framework.

• Journal of the Korean Geophysical Society
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• v.6 no.1
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• pp.1-11
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• 2003

There are numerous adjustment techniques that deal with the adjustment of geodetic networks but the least squares adjustment is the most common one. During the network adjustment procedure two techniques can be used, the free network adjustment technique and the constrained network adjustment technique. In order to determine the optimum technique for adjusting the geodetic networks, which used for the geodynamical purposes, data from two different geodetic networks "Sinai geodetic network, Egypt, and HGN network, South Korea" had been examined. The used networks had a different configuration and located in different areas with different seismic activity. The results show that both techniques have a high accuracy and no remarkable differences in terms of RMS. On the contrary, the resulted coordinates shows that the constrained network adjustment technique not only cause a remarkable distortion in the station final coordinates but also if the fixed points that define the datum parameters are changed different solutions for the coordinates will be determined. This distortion affect not only in the determination of point displacement but also in the estimation of the deformation parameters, which play a significant role in the geodynamical interpretation of results. Comparing the results which obtained from both techniques with the widely known geodynamical models of the area reviles that the free network adjustment technique results are clearly match with these models, while those obtained from the constrained technique didn’t match at all. By considering the results it seams to be that the free network adjustment technique is the optimum technique, which can be used for the geodetic network adjustment.

• Environmental and Resource Economics Review
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• v.12 no.4
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• pp.687-708
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• 2003

The purpose of this paper is to introduce time-series causality analysis by combining time-series technique with graph theory. Vector autoregressive (VAR) models can provide reasonable interpretation only when the contemporaneous variables stand in a well-defined causal order. We show that how graph theory can be applied to search for the causal structure In VAR analysis. Using Maryland crop cash prices and CBOT futures price data, we estimate a VAR model with directed acyclic graph analysis. This expands our understanding the degree of interconnectivity between the employed time-series variables.

• Journal of information and communication convergence engineering
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• v.9 no.6
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• pp.666-670
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• 2011

In this paper, we propose a stable active contour based tracking method which utilizes the bimodal segmentation technique to obtain a background color diminished image frame. The proposed method overcomes the drawback of the Mansouri model which is liable to fall into a local minimum state when colors appear in the background that are similar to the target colors. The Mansouri model has been a foundation for active contour based tracking methods, since it is derived from a probability based interpretation. By stabilizing the model with the proposed speed function, the proposed model opens the way to extend probability based active contour tracking for practical applications.