• Journal of the Society of Disaster Information
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• v.12 no.3
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• pp.235-241
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• 2016

Recently our country was entering a high-tech society with social and economic development. However, the individual's ability to respond to disasters is lowered by the increase in complexity society. Accurate situation assessment and disaster response by a margin of personal information that can identify when a disaster has been difficult. Until now, by leveraging Standard speaker was the emergency alert broadcast. However, it was difficult to have regular speakers reverberation, a distinct attenuation of sound by listening to the sound, etc. due to the reflection of sound. By using a directional speaker that is characteristic of the sound attenuation of sound is straight to solve this problem and obtain feedback on measures that can effectively provide the oocytes to a valid information on a disaster situation and the evacuation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.1005-1008
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• 2006

In this paper, we provide data of wireless environment in indoor for Bluetooth and wireless LAN systems. To accurately measure transmission characteristic for influence of the indoor wall, we used radiation measurement system with antennas. And various structure and material of the indoor wall are measured. Results of the measurement show that the attenuation of power is about $1\sim3dB$ for cement wall(25cm). In the case of cement wall with steel frame, the attenuation of power was increased using horizontal polarization but was not affect using vertical polarization.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.1
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• pp.8-14
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• 2014

This paper presents the intra capacitance modeling according to the winding method and section bobbin for CM choke capable of the EMI attenuation of broad bands from lower frequency bands to higher frequency bands and high frequency type common-mode choke capable of the EMI attenuation of high frequency band used in the EMI Block of LED-TV SMPS. In case of high frequency type CM choke, it can be explained the parasitic capacitance of A type and section bobbin type winding methods among them is much smaller than the other. The first resonant frequency of the proposed CM choke tends to increase as the parasitic capacitance becomes small and its impedance characteristics also show improved performance as the first resonant frequency increases. In the future, the CM chokes of high frequency type show it can be practically used in not only LED/LCD-TV SMPS but also several applications such as LED Lighting, Adapter and so on.

• Nuclear Engineering and Technology
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• v.53 no.4
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• pp.1323-1330
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• 2021

This work reported the radiation shielding characteristic of the bismuth titanium vanadium sodium tellurite glass system. The density of the specially-developed glass samples was increased from 2.21 to 4.01 g/cm³ with the addition of Bi₂O₃, despite the fact the molar volume is decease within 85.43-54.79 cm³/mol. The WinXcom program was used to approximate the effect of Bi₂O₃ on the gamma radiation shielding parameters of bismuth titanium vanadium sodium tellurite glasses. The ㎛ values decrease with the increase of Bi₂O₃ concentration. The computed data shows that the glass sample with 20 mol.% of Bi₂O₃ content has the greatest radiation attenuation performance in comparison to other selected glasses. The Bi₂O₃-TiO₂-V₂O₅-Na₂O-TeO₂ glass system shows excellent neutron shielding material with high long-term light transmittance and discharge resistance and could be potentially used as transparent radiation-resistant shielding glass applications.

• BMB Reports
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• v.42 no.2
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• pp.106-112
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• 2009

The bio-complex "reaction pattern in vertebrate cells"(RiV) is mainly represented by characteristic exosome-like particles - probably as reaction products of cells to specific stress. The transcription factor NF-kappaB plays a central role in inflammation. We tested the hypothesis that RiV particle preparations (RiV-PP) reduce cellular adhesion molecule (CAM) expression (ICAM-1, VCAM-1, E-selectin) by the attenuation of NF-kappaB translocation in human umbilical vein endothelial cells (HUVEC). After 4 hours, pre-incubation of HUVEC with RiV-PP before stimulation with TNF-alpha significantly reduced ICAM-1 (65.5${\pm}$10.3%) and VCAM-1 (71.1${\pm}$12.3%) mRNA expression compared to TNF-alpha-treated cells (100%, n=7). ICAM-1 surface expression was significantly albeit marginally reduced in RiV/TNF-alpha- treated cells (92.0${\pm}$5.6%, n=4). No significant effect was observed on VCAM-1 surface expression. In RiV/TNF-alpha-treated cells (n=4), NF-kappaB subunits p50 (85.7${\pm}$4.1%) and p65 (85.0${\pm}$1.8%) nuclear translocation was significantly reduced. RiV-PP may exert an anti-inflammatory effect in HUVEC by reducing CAM mRNA expression via attenuation of p50 and p65 translocation.

• Wind and Structures
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• v.29 no.6
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• pp.431-440
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• 2019

The aim of this study was to explore the influence of structure coupling effect on structural damping of blade based on the blade vibration characteristic. For this purpose, the scaled blade model of NREL 5 MW offshore wind turbine was processed and employed in the wind tunnel test to validate the reliability of theoretical and numerical models. The attenuation curves of maximum displacement and the varying curves of equivalent damping coefficient of the blade under the rated condition were respectively compared and analyzed by constructing single blade model and whole machine model. The attenuation law of blade dynamic response was obtained and the structure coupling effect was proved to exert a significant influence on the equivalent damping coefficient. The results indicate that the attenuation trend of the maximum displacement response curve of the single blade varies more obviously with the increase of elastic modulus as compared to that under the structure coupling effect. In contrast to the single blade model, the varying curve of equivalent damping coefficient with the period is relatively steep for the whole machine model. The findings are of great significance to guide the structure design and material selection for wind turbine blades.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.3A
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• pp.171-178
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• 2003

In this paper, We has proposed two DGS(Defected Ground Structure) resonators and designed the low-pass filter using the proposed DGS types. This structure consists of two rectangular slots, a ‘II type’ slot on the ground plane, and the stub at the transmission line. It has strong advantages that can vary the return loss at the passband freely and also can easily tune the attenuation pole frequency at the stopband. For enhancing the poor skirt property at the cutoff frequency of the Single Stub ‘II Type’ DGS cell, we have obtained the steep slope attenuation characteristic by combining the rectangular slot on both sides of the DGS. This type of the LPF with the proposed structure can be made more smaller than the existing filters and be used to find the various applications for eliminating the hamonics and spurious mode at WLL and the 2.4 GHz ISM band systems.

• Journal of Korean Biological Nursing Science
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• v.24 no.1
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• pp.17-25
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• 2022

Purpose: To determine the prognostic role of muscle area and muscle radiation attenuation in the erector spinae (ES) and multifidus (MF) muscles in patients undergoing gastrectomy. Methods: Patients with stage I-III gastric cancer undergoing gastrectomy were retrospectively enrolled in this study. Clinicopathologic characteristics were collected and analyzed. Both paraspinal muscle index of ES/MF muscles (PMI_EM) and paraspinal muscle radiation attenuation in the same muscles (PMRA_EM) were analyzed at the 3rd lumbar level using axial computed tomographic images. Cox regression analysis was applied to estimate overall survival (OS) and disease-free survival (DFS). Results: There was only a weak correlation between PMI_EM and PMRA_EM (r= 0.28). Multivariate Cox regression revealed that PMRA_EM, but not PMI_EM, was an important determinant of survival. PMRA_EM along with age, tumor-node-metastasis (TNM) stage, perineural invasion, and serum albumin level were significant determinants of both OS and DFS that constituted Model 1. Harrell's concordance index and integrated area under receiver operating characteristic curve were greater for Model 1 than for Model 2 (consisting of the same covariates as Model 1 except PMRA_EM) or Model 3 (consisting of only TNM stage). Conclusion: PMRA_EM, but not PMIEM, was an important determinant of survival. Because there was only a weak correlation between PMI_EM and PMRA_EM in this study, it was presumed that they were mutually exclusive. Model 1 consisting of age, TNM stage, perineural invasion, serum albumin level, and PMRA_EM was greater than nested models (i.e., Model 2 or Model 3) in predicting survival outcomes.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.2
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• pp.122-129
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• 2001

A characterization procedure for analyzing symmetric coupled MIS(Metal-Insulator-Semiconductor) transmission line is used the same procedure as a general single layer symmetric coupled line with perfect dielectric substrate from the extraction of the characteristic impedance and propagation constant for even- and odd-mode. In this paper, an analysis for a new substrate shielding symmetric coupled MIS structure consisting of grounded crossbar at the interface between Si and SiO2 layer using the Finite- Difference Time-Domain(FDTD) method is presented. In order to reduce the substrate effects on the transmission line characteristics, a shielding structure consisting of grounded crossbar lines over time-domain signal has been examined. Symmetric coupled MIS transmission line parameters for even- and odd-mode are investigated as the functions of frequency, and the extracted distributed frequency- dependent transmission line parameters and corresponding equivalent circuit parameters as well as quality factor for the new MIS crossbar embedded structure are also presented. It is shown that the quality factor of the symmetric coupled transmission line can be improved without significant change in the characteristic impedance and effective dielectric constant.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.2
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• pp.178-182
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• 2004

In this paper, a 90$^{\circ}$ hybrid coupler with both power division and harmonic rejection characteristics is presented by applying a LPF characteristic to a conventional 90$^{\circ}$ hybrid. Since a conventional 90$^{\circ}$ hybrid coupler operates as a power divider/combiner using phase difference, it does not suppress higher order harmonics when it is incorporated with nonlinear amplifier. This requires an additional filter to take into account of the harmonics. The proposed 90$^{\circ}$hybrid coupler power provides the division capability and proper phase difference, as well as harmonic suppression characteristic by integrating LPF characteristic.