• Journal of Environmental Science International
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• v.18 no.8
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• pp.911-918
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• 2009

Electromagnetic interference (EMI) is defined as the interaction phenomena of electromagnetic waves scattered from a large structure or complex terrain. In this study, the propagation of linear wave is modeled with ray theory, direct simulation Monte Carlo (DSMC), and some classical theories on flat plates. The wave physics of reflection, refraction, and diffraction are simulated for the investigation of front and back scattering of the one-dimensional plane wave from a tower with ray theory and DSMC, respectively. The effect of rotating disk idealized from the real wind-turbine blades is modeled with a simplified version of the classical electromagnetic theory as well as DSMC based on the ray theory.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.733-739
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• 2023

The purpose of this study verify to the effect of applying the X-ray screening ability rating for security screening persons in Incheon International Airport. Data collected through a evaluation score of 1,034 security screening persons in Incheon International Airport. Data analysis performed using paired sample t-test. The research results found that it was a statistically significant difference pre-test and post-test applying the X-ray screening ability rating. In this article, we asserts that the X-ray screening ability rating is effective in improving the X-ray screening ability of security screening persons. This paper contribute to the academic expansion of motivation theory and self-determination theory. This study is valuable as a preemptive empirical research that provides practical implications about the application of X-ray screening ability rating for security screening persons.

• Journal of radiological science and technology
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• v.17 no.1
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• pp.97-109
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• 1994

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.741-745
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• 1991

This paper describes a feature extraction in digitized chest X-ray image and CT head Image. There are Extraction, Thresholding, Region G rowing, Split-Merge and Relaxation in feature extraction technique. In this study, Region Growing System was realized and Fuzzy Set Theory was applied in order to extract the vague region which the conventional method has difficulties in extracting. The performance of proposed algorithm was proved by being applied to chest X-ray image and CT head image.

• The Journal of Natural Sciences
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• v.8 no.2
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• pp.101-109
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• 1996

In this paper, using the derived formula based on field theory both geometrical optics and diffraction theory, several features of same buildings of Bertoni's construction that influence the propagation of signals between antennas located on the same floor have been investigated theoretically and compared with previously studied results.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.1062-1070
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• 2022

In the present communication, pure and stable α-Bismuth Oxide (Bi₂O₃) nanoparticles (NPs) were synthesized by low temperature solution combustion method using urea as a fuel and calcined at 500℃. The synthesized sample was characterized by using powder X-ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), Energy dispersive X-ray analysis (EDAX), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and UV-Visible absorption spectroscopy. The PXRD pattern confirms the formation of mono-clinic, stable and low temperature phase α-Bi₂O₃. The direct optical energy band gap was estimated by using Wood and Tauc's relation which was found to be 2.81 eV. The characterized sample was studied for X-ray/gamma ray shielding properties in the energy range 0.081-1.332 MeV using NaI (Tl) detector and multi channel analyzer (MCA). The measured shielding parameters agrees well with the theory, whereas, slight deviation up to 20% is observed below 356 keV. This deviation is mainly due to the influence of atomic size of the target medium. Furthermore an accurate theory is necessary to explain the interaction of X-ray/gamma ray with the NPs.The present work opens new window to use this facile, economical, efficient, low temperature method to synthesize nanomaterials for X-ray/gamma ray shielding purpose.

• Journal of electromagnetic engineering and science
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• v.1 no.1
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• pp.48-53
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• 2001

This paper presents a new 3-D ray tracing technique based on the image theory with newly defined ray tubes. The proposed method can be applied to indoor environments with arbitrary building layouts and has high computational efficiency compared to the precedent methods resorting to the ray launching scheme. It predictions are in good agreement with the measurements.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.1067-1071
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• 2000

This paper presents a new 3-D ray tracing technique based on the image theory with newly defined ray tubes. The proposed method can be applied to indoor environments with arbitrary building layouts and has high computational efficiency compared to the precedent methods resorting to the ray launching scheme. Its predictions are in good agreement with the measurements

• Structural Engineering and Mechanics
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• v.42 no.2
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• pp.269-289
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• 2012

Free vibration and dynamic responses of piles semi-rigidly connected with the superstructures are investigated. Timoshenko beam theory is employed to characterize the pile partially embedded in a two-parameter elastic foundation. The formulations for the method of reverberation-ray matrix (MRRM) are then derived to investigate the dynamics of the pile with surface cracks, which are modeled as massless rotational springs. Comparison with existent numerical and experimental results indicates the proposed method is very effective and accurate for dynamic analysis, especially in the high frequency range. Finally, the effects of some physical parameters on the natural frequencies, frequency responses and transient responses of the piles are studied.

• Korean Journal of Crystallography
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• v.19 no.1
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• pp.1-6
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• 2008

The reaction of dilithio-o-carborane with dipenyl disulfide produces a phenyl thiolated o-carborane and it has been confirmed that there is conformational similarity between the structure of the compound elucidated by X-ray crystallography and that calculated by ab initio and density functional theory.