• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.7
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• pp.14-21
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• 2001

In this paper, we designed and fabricated C-band bandpass filter using dielectric resonators. From waveguide cutoff frequency which applied the region between adjacent dielectric resonators, the height of cavity is determined. The cavity's diameter is determined to the twice of dielectric resonator? diameter considering the conductor loss. The resonant frequency of the DR cavity is calculated with non decaying mode analysis. Conventionally, cylindrical dielectric resonator is analysed by Cohn's model which use the decaying mode in the region between dielectric resonator wall and circular cavity wall, which is an approximated method. The external quality factor, $Q_{ex}$ has found with simulation result using Ansoft's Maxwell simulation tool. The designed filter using dielectric resonators with dielectric constant of 45 has the passband center at 5.065GHz. The bandpass filter using dielectric resonators has about 1dB insertion loss, 20MHz bandwidth and more than 30dB attenuation at $f_0+15MHz$.

• The Journal of the Acoustical Society of Korea
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• v.19 no.2
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• pp.33-39
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• 2000

We have studied to obtain the frequency characteristics of the Surface Acoustic Wave(SAW) bandpass filter, having low shape factor, it's interdigital transducer(IDT) was formed on the 35° Y-cut X-propagation Quartz substrate and was evaporated by Aluminium. And then, we performed computer-simulation by a simulator. And, we can design that the apodization weighted type IDT as an input transducer of the filter and the withdrawal weighted type IDT as an output transducer of the filter from the results of our computer-simulation. Also, we have employed that the number of pairs of the input and output IDT are 2200 pairs and 1000pairs, respectively and used the Kaiser-Bessel window function in order to minimize the effect of ripple. And, while the width and the space of IDT's finger are 6㎛ m and 5.75㎛, respectively and we could obtain the resonable results when the IDT thickness was 6000Å in consideration of the ratio of SAW's wavelength, and IDT aperture is 2mm. Frequency response of the fabricated SAW bandpass filter has the property that the center frequency is about 70MHz, shape factor is less than 1.3, bandwidth at the 1.5dB is probably 1.3MHz, out-band attenuation is almost -45dB, insertion loss is 19dB and ripple in the width of bandpass is 1dB approximately. Therefore, these frequency characteristics of the fabricated SAW bandpass filter are agreed well with the designed values.

• Journal of Distribution Science
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• v.14 no.6
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• pp.89-98
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• 2016

Purpose - This article tackles risk communication issues and aims to address the characteristics of MERS risk information distribution in South Korea, and secondly to examine the communicative behavior of the public health authority in terms of the quality of communication strategies. Thirdly, the study attempts to figure out the risk communication to cope with MERS through the applications of SMCRE model in chronological order. We employ the social amplification of risk framework for analyzing the emergent public response as one of the main approaches. Research Design, Data and Methodology - The main framework of this study is theoretically based on the social amplification of risk, which describes signals about risk transmitted and processed by individuals and social groups. The model also reflects the interactions between social groups and institutes about disaster-related risk issues, which are potential amplifiers or attenuators of communication signals. S-M-C-R-E Model is methodologically employed to examine the social amplification for MERS risk information in each period, which we defined operationally. The proposed methodology allows the assessment of effectiveness and ineffectiveness on risk communication to be conceptualized as a countermeasure against disasters. The paper focuses on exploring how social risk amplification can be applied and organized in each stage. Results - The SMCRE model describes the exchange of risk information and is also applied to all forms of communication between stakeholders including public health authority, local government and media. Each factor of risk communication includes source, message, channel, receiver and effect. The results support that the effective risk communication involves not only the improved reliability of public health authority as a key factor of risk communication, but also a close cooperation and good collaboration with local governments. It does not seem to be possible that the government-initiated risk communication based on controllability and management cope effectively with infectious disease in early stage. The results of this study imply that the shared risks between local, regional and national authorities can enhance risk communication system. Conclusions - The study supports that the disparities in how disaster-related risk information is interpreted and coded, have made effective risk communication and public sense-making impeded. Our findings support a more communicative discussion about the role of risk information sharing between governments for the improvement of emergency management and underline the importance of social elements in the risk communication, such as relationship and trust building. Findings suggest that trust building between stakeholders could be added to help explain the processes of social amplification and attenuation of risk. It would be recommended that the continuous risk communication with all the involved stakeholders will be able to help national health promotion policy to be improved regarding emergency management. Furthermore, risk communication has to be a scientific approach for the communication pertaining to potentially sensitive or controversial situations with public concerns and low public trust.

• Journal of the Korean Society of Radiology
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• v.16 no.5
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• pp.553-558
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• 2022

The purpose of this work was a simulation study to evaluate the virtual monochromatic (VM) image quality of blood vessels compared to the monochromatic image. Dual-energy images were obtained based on the linear attenuation coefficients of five materials at 50 keV and 80 keV at low- and high-energies, respectively. A weighting factor is required to synthesize the VM image, and the liver and bone were used as basis materials to obtain the weighting factor. VM images were synthesized at energies ranging from 30 keV to 100 keV. Image quality was evaluated by Contrast to noise ratio (CNR) and noise by setting calcium and contrast medium as signals and blood as background. According to the results, the energies with the maximum CNR were 50 keV and 60 keV for calcium and contrast medium, respectively. The energies showing the minimum noise were 70 keV, 70 keV, and 60 keV in calcium, iodine contrast medium, and blood, respectively. The VM image can contribute to the improvement of diagnostic performance in CT examination because it can implement an image at the optimal energy that minimize noise and maximize CNR.

• Nutrition Research and Practice
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• v.16 no.5
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• pp.589-603
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• 2022

BACKGROUND/OBJECTIVES: Previous studies have reported that protein supplementation contributes to the attenuation of inflammation. Serious trauma such as burn injury usually results in the excessive release of inflammatory factors and organs dysfunction. However, a few reports continued to focus on the function of protein ingestion in regulating burn-induced inflammation and organ dysfunction. MATERIALS/METHODS: This study established the rat model of 30% total body surface area burn injury, and evaluated the function of blended protein (mixture of whey and soybean proteins). Blood routine examination, inflammatory factors, blood biochemistry, and immunohistochemical assays were employed to analyze the samples from different treatment groups. RESULTS: Our results indicated a decrease in the numbers of white blood cells, monocytes, and neutrophils in the burn injury group administered with the blended protein nutritional support (Burn+BP), as compared to the burn injury group administered normal saline supplementation (Burn+S). Expressions of the pro-inflammatory factors (tumor necrosis factor-α and interleukin-6 [IL-6]) and chemokines (macrophage chemoattractant protein-1, regulated upon activation normal T cell expressed and secreted factor, and C-C motif chemokine 11) were dramatically decreased, whereas anti-inflammatory factors (IL-4, IL-10, and IL-13) were significantly increased in the Burn+BP group. Kidney function related markers blood urea nitrogen and serum creatinine, and the liver function related markers alanine transaminase, aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase were remarkably reduced, whereas albumin levels were elevated in the Burn+BP group as compared to levels obtained in the Burn+S group. Furthermore, inflammatory cells infiltration of the kidney and liver was also attenuated after burn injury administered with blended protein supplementation. CONCLUSIONS: In summary, nutritional support with blended proteins dramatically attenuates the burn-induced inflammatory reaction and protects organ functions. We believe this is a new insight into a potential therapeutic strategy for nutritional support of burn patients.

• International Journal of Computer Science & Network Security
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• v.23 no.10
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• pp.1-10
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• 2023

This paper proposes a method to extend Inter-Carrier Interference (ICI) canceling Orthogonal Frequency Division Multiplexing (OFDM) receivers for 5G mobile systems to spatial multiplexing 2×2 MIMO (Multiple Input Multiple Output) systems to support high-speed ground transportation services by linear motor cars traveling at 500 km/h. In Japan, linear-motor high-speed ground transportation service is scheduled to begin in 2027. To expand the coverage area of base stations, 5G mobile systems in high-speed moving trains will have multiple base station antennas transmitting the same downlink (DL) signal, forming an expanded cell size along the train rails. 5G terminals in a fast-moving train can cause the forward and backward antenna signals to be Doppler-shifted in opposite directions, so the receiver in the train may have trouble estimating the exact channel transfer function (CTF) for demodulation. A receiver in such high-speed train sees the transmission channel which is composed of multiple Doppler-shifted propagation paths. Then, a loss of sub-carrier orthogonality due to Doppler-spread channels causes ICI. The ICI Canceller is realized by the following three steps. First, using the Demodulation Reference Symbol (DMRS) pilot signals, it analyzes three parameters such as attenuation, relative delay, and Doppler-shift of each multi-path component. Secondly, based on the sets of three parameters, Channel Transfer Function (CTF) of sender sub-carrier number n to receiver sub-carrier number l is generated. In case of n≠l, the CTF corresponds to ICI factor. Thirdly, since ICI factor is obtained, by applying ICI reverse operation by Multi-Tap Equalizer, ICI canceling can be realized. ICI canceling performance has been simulated assuming severe channel condition such as 500 km/h, 8 path reverse Doppler Shift for QPSK, 16QAM, 64QAM and 256QAM modulations. In particular, 2×2MIMO QPSK and 16QAM modulation schemes, BER (Bit Error Rate) improvement was observed when the number of taps in the multi-tap equalizer was set to 31 or more taps, at a moving speed of 500 km/h and in an 8-pass reverse doppler shift environment.

• Economic and Environmental Geology
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• v.41 no.2
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• pp.225-242
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• 2008

The site effect for 23 broadband seismic stations in the southern Korean Peninsula was estimated by using the spectral ratio of coda waves. In principle, the site effect means the pure amplification below the station excluding effects of seismic source and attenuation in the wave transmission. However, the site effect determined in this study is equivalent with the relative site amplification factor to the mean amplification for all stations. A total of 500 three-component seismograms from 35 earthquakes, of which magnitude ranged from 2.5 to 5.1 occurred from January, 2001 to January, 2007 was used to obtain the site amplification factor. The site amplification factors were estimated for the frequency bands centered at 0.2, 0.5, 1, 2, 5, 10, 15, and 20 Hz. It was found that the factors for two horizontal components of transverse and radial records were concordant with each other in the all frequency bands. However, the factor for the vertical component was found to be systematically lower than those for two horizontal components. The factors obtained in the low frequency band below 2 Hz ranged from 0.5 to 1.5 in all seismic stations except for KMA and KIGAM stations in Bagryeongdo (BRD1 and BRD2) of which factor showed high value above 1.5. Some stations such as SEO, SNU, HKU, NPR, and GKPI showed high value above 1.5 in the high frequency band from 5 to 20 Hz. Especially, the factors of GKP1 station represented extremely high value ranging from 1.8 to 7.8. Also, the factors for stations of KWJ, SND, and ULJ showed low value below 0.5. The spatial distribution for the relative amplification factor represented a tendency of being approximately lower in north-eastern area than south-western area in the southern Korean Peninsula.

• Journal of Life Science
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• v.29 no.4
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• pp.484-491
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• 2019

Proanthocyanidins are naturally occurring polyphenolic compounds abundant in many vegetables, plant skins (rind/bark), seeds, flowers, fruits, and nuts. Numerous in vitro and in vivo studies have demonstrated myriad effects potentially beneficial to human health, such as antioxidation, immunomodulation, DNA repair, and antitumor activity. Among immune cells, macrophages are crucial players in a variety of inflammatory responses to environmental conditions. However, it has been widely reported that macrophages cause chronic inflammation and are involved in a variety of diseases, such as obesity, diabetes, metabolic syndrome, and cancer. In this study, we report the suppressive effect of proanthocyanidins via the heme oxygenase-1 (HO-1)-related system, on the immune response of the LPS-stimulated mouse macrophage cell line RAW264.7. Increased HO-1 expression at mRNA and protein levels were found in proanthocyanidins-treated RAW264.7 cells. Further, proanthocyanidins enhanced nuclear factor-erythroid 2-related factor 2 translocation into the nucleus. RAW264.7 cells were treated with lipopolysaccharide (LPS) with or without proanthocyanidins, and inflammatory mediator expression levels were assessed. Proanthocyanidins treatment resulted in the attenuation of nitric oxide production and inducible nitric oxide synthase expression in LPS-stimulated RAW264.7 cells. In addition, mRNA and protein expression of proinflammatory cytokines, such as tumor necrosis factor-${\alpha}$ and interleukin-6, was inhibited by proanthocyanidins treatment in LPS-stimulated RAW264.7 cells. These findings support proanthocyanidins as a promising anti-inflammatory agent.

• Journal of Radiation Protection and Research
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• v.33 no.1
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• pp.13-20
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• 2008

The flow rate measurements in a multi-phase flow pipeline were evaluated quantitatively by means of a clamp-on sealed radioisotope based on a cross correlation signal processing technique. The flow rates were calculated by a determination of the transit time between two sealed gamma sources by using a cross correlation function following FFT filtering, then corrected with vapor fraction in the pipeline which was measured by the ${\gamma}$-ray attenuation method. The pipeline model was manufactured by acrylic resin(ID. 8 cm, L=3.5 m, t=10 mm), and the multi-phase flow patterns were realized by an injection of compressed $N_2$ gas. Two sealed gamma sources of $^{137}Cs$ (E=0.662 MeV, ${\Gamma}$ $factor=0.326\;R{\cdot}h^{-1}{\cdot}m^2{\cdot}Ci^{-1}$) of 20 mCi and 17 mCi, and radiation detectors of $2"{\times}2"$ NaI(Tl) scintillation counter (Eberline, SP-3) were used for this study. Under the given conditions(the distance between two sources: 4D(D; inner diameter), N/S ratio: $0.12{\sim}0.15$, sampling time ${\Delta}t$: 4msec), the measured flow rates showed the maximum. relative error of 1.7 % when compared to the real ones through the vapor content corrections($6.1\;%{\sim}9.2\;%$). From a subsequent experiment, it was proven that the closer the distance between the two sealed sources is, the more precise the measured flow rates are. Provided additional studies related to the selection of radioisotopes their activity, and an optimization of the experimental geometry are carried out, it is anticipated that a radioisotope application for flow rate measurements can be used as an important tool for monitoring multi-phase facilities belonging to petrochemical and refinery industries and contributes economically in the light of maintenance and control of them.

• Korean Journal of Remote Sensing
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• v.28 no.1
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• pp.69-77
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• 2012

Surface insolation is one of the major indicators for climate research over the Earth system. For the climate research, long-term data and wide range of spatial coverage from the data observed by two or more of satellites of the same orbit are needed. It is important to improve the continuity and consistency of the derived products, such as surface insolation, from different satellites. In this study, surface insolations based on Geostationary Operational Environmental Satellite (GOES-9) and Multi-functional Transport Satellites (MTSAT-1R) were compared during overlap period using physical model of insolation to find ways to improve the consistency and continuity between two satellites through comparison of each channel data and ground observation data. The thermal infrared brightness temperature of two satellites show a relatively good agreement between two satellites : rootmean square error (RMSE)=5.595 Kelvin; Bias=2.065 Kelvin. Whereas, visible channels shown a quite different values, but it distributed similar tendency. And the surface insolations from two satellites are different from the ground observation data. To improve the quality of retrieved insolations, we have reproduced surface insolation of each satellite through adjustment of the Cloud Factor, and the Cloud Factor for GOES-9 satellite is modified based on the analysis result of difference channel data. As a result, the insolations estimated from GOES-9 for cloudy conditions show good agreement with MTSAT-1R and ground observation : RMSE=$83.439W\;m^{-2}$ Bias=$27.296W\;m^{-2}$. The result improved accuracy confirms that the modification of Cloud Factor for GOES-9 can improve the continuity and consistency of the insolations derived from two or more satellites.