• Geophysics and Geophysical Exploration
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• v.22 no.4
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• pp.225-238
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• 2019

Migration velocity analysis (MVA) for creating optimum depth-domain velocities in seismic imaging was applied to marine long-offset multi-channel data, and the effectiveness of the MVA approach was demonstrated by the combinations of conventional data processing procedures. The time-domain images generated by conventional time-processing scheme has been considered to be sufficient so far for the seismic stratigraphic interpretation. However, when the purpose of the seismic imaging moves to the hydrocarbon exploration, especially in the geologic modeling of the oil and gas play or lead area, drilling prognosis, in-place hydrocarbon volume estimation, the seismic images should be converted into depth domain or depth processing should be applied in the processing phase. CMP-based velocity analysis, which is mainly based on several approximations in the data domain, inherently contains errors and thus has high uncertainties. On the other hand, the MVA provides efficient and somewhat real-scale (in depth) images even if there are no logging data available. In this study, marine long-offset multi-channel seismic data were optimally processed in time domain to establish the most qualified dataset for the usage of the iterative MVA. Then, the depth-domain velocity profile was updated several times and the final velocity-in-depth was used for generating depth images (CRP gather and stack) and compared with the images obtained from the velocity-in-time. From the results, we were able to confirm the depth-domain results are more reasonable than the time-domain results. The spurious local minima, which can be occurred during the implementation of full waveform inversion, can be reduced when the result of MVA is used as an initial velocity model.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.274-274
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• 2012

In-depth analysis by secondary ion mass spectrometry (SIMS) is very important for the development of electronic devices using multilayered structures, because the quantity and depth distribution of some elements are critical for the electronic properties. Correct determination of the interface locations is critical for the calibration of the depth scale in SIMS depth profiling analysis of multilayer films. However, the interface locations are distorted from real ones by the several effects due to sputtering with energetic ions. In this study, the determination of interface locations in SIMS depth profiling of multilayer films was investigated by Si/Ge and Ti/Si multilayer systems. The original SIMS depth profiles were converted into compositional depth profiles by the relative sensitivity factors (RSF) derived from the atomic compositions of Si-Ge and Si-Ti alloy reference films determined by Rutherford backscattering spectroscopy. The thicknesses of the Si/Ge and Ti/Si multilayer films measured by SIMS depth profiling with various impact energy ion beam were compared with those measured by TEM. There are two methods to determine the interface locations. The one is the feasibility of 50 atomic % definition in SIMS composition depth profiling. And another one is using a distribution of SiGe and SiTi dimer ions. This study showed that the layer thicknesses measured with low energy oxygen and Cs ion beam and, by extension, with method of 50 atomic % definition were well correlated with the real thicknesses determined by TEM.

• Journal of the Korean Vacuum Society
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• v.8 no.3B
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• pp.283-289
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• 1999

Multilayer thin film reference materials for the sputter depth profiling analysis are used to calibrate the sputter depth scale by measuring the sputtering rate and to optimize the sputtering conditions for the best depth resolution. Surface analysis group of Korea Research Institute of Standards and science (KRISS) have developed various types of multilayer thin films by using an ion beam sputter deposition and in-situ surface analysis system. The chemical states of the thin films reference materials were certified by in-situ XPS and the thicknesses were certified by transmission electron microscopy (TEM).

• Journal of Korean Society of Water Science and Technology
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• v.26 no.6
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• pp.133-142
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• 2018

Increasing localized torrential rainfall caused by abnormal climate are making higher damage to human and property through urban inundation So The need of preventive measures is being highlighted. In this study, the methodology for calculating flood depth in domestic water map using an interpolation method in order to utilizing the results of flood analysis provided only in the form of a report is suggested. In the Incheon Metropolitan City S area as the test-bed, the flood depth was calculated using the interpolating the actual flood analysis by image and verification was performed. Verification results showed that the error rate was 5.2% for the maximum flooding depth, and that the water depth value was compared to 10 random points, which showed a difference of less than 0.030 m. Also, as the results of the flood analysis were presented in various ways, the flood depth was extracted from the image of the result of the flood analysis, which changed the presentation method, and then compared and analyzed. The results of this study could be available for the use of basic data from the research on the urban penetration of domestic consumption and for decision-making of policy.

• Journal of Wind Energy
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• v.15 no.1
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• pp.69-81
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• 2024

In order to understand water depth distribution in the waters of the southwestern sea offshore wind power demonstration complex, field observations were conducted using a multi-beam echosounder from before construction (2018.2) to operation (2022.8). After data processing and correction of the observed depth, cross-sectional analysis was performed to calculate the maximum water depth value, and time phase analysis was performed using the maximum water depth value. The maximum water depth change rate over time tended to gradually decrease, and there was little difference in the rate of change before the construction of the wind turbine foundation structure, and the rate of change was rapid when the foundation structure was under construction. As a result of time phase analysis, the rate of change of the first (2018.02) and the second (2018.05) showed a rate between -6.27 and -4.13, on average, as the rate of change before the construction of the offshore wind farm, and there was no difference between the first and second rates. The third (2018.11) rate of change was -4.25 to -1.82, and the fourth (2019.04) rate of change was -2.34 to -1.22, and the rate of change increased rapidly after the third time. The fifth (2019.07) rate of change was -2.11 to -1.31, the sixth (2021.05) rate of change was -2.09 to -1.28, and the seventh (2022.08) was -2.11 to -1.22 rate of change, and after the rate of change reached some extent, the change was analyzed in an insufficient graph.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.27-32
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• 2007

Determination of crack depth in filed using the self-calibrating surface wave transmission measurement and the cutting frequency in the transmission function (TRF) is very difficult due to variations of the measurement conditions. In this study, it is proposed to use the measured full TRF as a feature for crack depth assessment. A principal component analysis (PCA) is employed to generate a basis of the measured TRFs for various crack cases. The measured TRFs are represented by their projections onto the most significant principal components. Then artificial neural networks (NNs) using the PCA-compressed TRFs is applied to assess the crack in concrete. Experimental study is carried out for five different crack cases to investigate the effectiveness of the proposed method. Results reveal that the proposed method can be effectively used for the crack depth assessment of concrete structures.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.799-804
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• 2002

This paper is mainly Intended to show an effect of foundation depth on heat of hydration in mass concrete. From the analysis, it was found that the foundation depth which is not affected by the heat conduction is more than 5 m. But this study shows that, an optimum foundation depth for the FEM analysis for heat of hydration in mass concrete is approximately 1 m from this study. And in order to study tile significance of various parameters, a sensitivity analysis of heat transfer in mass concrete is performed and the amount of heat liberated at complete hydration of unit weight of cement and the reaction velocity of hydration are the most sensitive parameters factors of other various parameters.

• Journal of the Korean GEO-environmental Society
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• v.18 no.3
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• pp.15-23
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• 2017

Gangwon Province, located in the northeastern part of South Korea, is the coldest area in South Korea with 90% of the total area as mountainous. Therefore, tunnel damage has been reported continuously in winter. But there has been lack of researches on frost heave occurring behind tunnel lining. In this study, numerical analysis was conducted to investigate the frost depth in road tunnel constructed in Gangwon province. Based on the database on road tunnel and weather in Gangwon province, a standard tunnel shape and geotechnical properties of ground was determined. And then thermal analysis for the frost depth according to the temperature change and ground conditions were conducted. Analysis result showed that the sensitivity to frost heave of metamorphic rock and sedimentary rock is higher than sand. Lower initial ground temperature leads to deeper frost depth and consequently increases frost damage. In addition, lining thickness, specific heat capacity, and thermal conductivity also affect greatly on the variation of frost depth.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.1
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• pp.15-26
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• 2002

The purpose of this study was to classier the somatotype of late middle-aged women and to analyze the characteristics of each somatotype. The subjects were 337 late middle-aged women and their age range os from 45 to 59 fears old. Data were collected through anthropometry and photometry and analyzed by factor analysis, cluster analysis and discriminant analysis. The results were as follows; 1. The result of factor analysis indicated that 9 factors were extracted through factor analysis and those factors comprised 83.56 percent of total valiance. 2. Using factor scores, cluster analysis was carried out and the subject were classified into 4 cluster. Each cluster was classified as their body front and side view contour. Type 1 is tall, slim, and lower balk is flat on the side. Type 2 is standard and lean-back type on the side. Type 3 is standard height and weight, H type in front, and belly-protruded on the side. Type 4 is short, fat, and the side is hip-protruded. 3. According to the stepwise discriminant analysis, the 9 important items in classifying the somatotype of the late middle-aged women are as follows ; lower back tilt angle, hip depth(back) -back waist depth(back), bust depth(fore) - anterior waist depth(fore), jugular fossa point(fore), upper back tilt angle, burst breadth -waist breadth, right shoulder tilt, height of shoulder - height of anterior waist, abdomen breath. The correct classification rate for these items is as exact as 84.62%.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.702-704
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• 2003

In this paper, analysis of bobbin probe signal in steam generator tube with bulge defect on CE system 80 nuclear power plant is represented. The CE system 80 steam generator is adopted in ULJIN-4 nuclear power plant. From Maxwell's equation, the electromagnetic governing equation for eddy current problem is derived and by performing the finite element formulation the 3-dimensional finite element code with brick element is developed. For the ease of the comparison the numerical results with experimental ones, the calculated signals are adjusted by using the ASME standard 100[%] through hole signal. For analysis of the effect of variation of the bulge depth on the impedance signal 0.2[mm] and 0.4[mm] depth of bulge defect signals are calculated and analyzed. As the depth of the bulge defect is increased, the magnitude of the signal is increased, too. But the rate of the increment of the signal is less than that of the depth of defect. From the result of this paper, we can obtained the information of the effect of bulge defect on the impedance signal.