• Journal of Biosystems Engineering
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• v.41 no.2
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• pp.108-115
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• 2016

Purpose: Radio frequency (RF) heating is a promising thawing method, but it frequently causes undesirable problems such as non-uniform heating. This can occur because of the food shape, component distribution, and initial temperature differences between food parts. In this study, RF heating was applied to the thawing of cylindrically shaped pork sirloin by changing the shape of electrodes and the surrounding temperature. Methods: Curved electrodes were utilized to increase the thawing uniformity of cylindrically shaped frozen meat. Pork sirloin in the shape of a half-circle column was frozen in a deep freezer at $-70^{\circ}C$ and then thawed by RF heating with flat and curved electrodes. In order to prevent fast defrosting of the food surface by heat transfer from air to the food, the temperature of the thawing chamber was varied by -5, -10, and $-20^{\circ}C$. The temperature values of the frozen pork sirloin during RF thawing were measured using fiber-optic thermo sensors. Results: After multiple applications of curved electrodes resembling the food shape, and a cooled chamber at $-20^{\circ}C$ the half-cylindrically shaped meat was thawed without surface burning, and the temperature values of each point were similarly increased. However, with the parallel electrode, the frozen meat was partially burned by RF heating and the temperature values of center were overheated. The uniform heating rate and heat transfer prevention from air to the food were crucial factors for RF thawing. In this study, these crucial factors were accomplished by using a curved electrode and lowering the chamber temperature. Conclusions: The curved shape of the electrode and the equipotential surface calculated from the modeling of the parallel capacitor showed the effect of uniform heating of cylindrically shaped frozen food. Moreover, the low chamber temperature was effective on the prevention of the surface burning during RF thawing.

• Journal of Korean Physical Therapy Science
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• v.9 no.3
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• pp.19-29
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• 2002

This study questionnaires 166 inpatients and outpatients with stroke in 8 hospitals, including Wonkwang University Gwangju Korean Hospital from July 2 to 31, 2001 in order to find out the influence of general nature, smoking, drinking, obesity, and perception of saltness of patients with stork on the outbreak of stroke and to examine important factors by dividing into hemorrhagic and ischemic stroke. Finally, collected data is analyzed statistically, using SPSS 7.5 statistics package. This study reaches a conclusion as follows. 1. For general nature, 86(51.8%) patients have hemorrhagic stroke and 80(48.2%), ischemic stroke in the rate of 1.59:1(male:female), suggesting that male's outbreak is more than female's. Outbreak age is ranged from 20 years to 90 years in order of 60's, 50's, and 40's. 50's-60's accounts for more than half percentage. 2. For smoking, 73(71.6%) of male patients has smoking experience and their 562% has ischemic stroke. Their cross-analysis for hemorrhagic and ischemic stroke shows significant difference with $x^2=3.90$(p<0.05). 48.6% of patients with smoking experience is ranged from 1 to 10 a day in smoking quantity. 3. For drinking, 90(88.2%) of male patients has drinking experience and their 53.3% has hemorrhagicstroke. Their cross-analysis for hemorrhagic and ischemic stroke shows no significant difference with x2=3.40(p<0.1). 59.3% of patients with drinking experience is classified as a overdrinking group. 4. For obesity, low weight is 8(4.8%): normal, 111(66.9%): excessive, 40(24.1%), and obesity, 7(4.2%). In patients with hemorrhagic stroke, excessive weight and obesity are somewhat high(33.7%). The cross-analysis for male's hemorrhagic and ischemic stork by dividing BMI into more and less than 25 shows no significant difference with x=3.52(p<0.1). 5. For perception of saltness, 21(12.7%) patients eat flat: 76(45.8%) normally, and 69(41.5%), saltily. Many patients with ischemic stroke are classified as a group who eat saltily. The cross-analysis for male's hemorrhagic and ischemic stroke shows signifiant difference with x2=10.99(p<0.05). As this study has small sample and selects inpatient and outpatient in certain local hospital, it is difficult to generalize. But the cross-analysis of male's hemorrhagic and ischemic stroke shows signifiant difference in smoking and perception of saltness. Drinking and obesity are more important factors in hemorrhagic stroke and smoking and perception of saltness in ischemic stroke.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.2
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• pp.225-241
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• 2007

A closed flux chamber system was used for measuring major greenhouse gas (GHG) emission from tideland and/or wetland soils in estuarine area at Saemankum, Kunsan in southwestern Korea during from months of February to June 2006. Hourly averaged GHG soil emissions were measured two to three times a day during the ebb tide hours only. Site soils were analyzed for soil parameters (temperature, pH, total organic contents, N and C contents in soil) in the laboratory. Soil GHG fluxes were calculated based on the GHG concentration rate of change measured inside a closed chamber The analysis of GHG was conducted by using a Gas Chromatography (equipped with ECD/FID) at laboratory. Changes of daily, monthly GHGs' fluxes were examined. The relationships between the GHG emissions and soil chemical contents were also scrutinized with respect to gas production and consumption mechanism in the soil. Soil pH was pH $7.47{\pm}0.49$ in average over the experimental period. Organic matter contents in sample soil was $6.64{\pm}4.98\;g/kg$, and it shows relatively lower contents than those in agricultural soils in Kunsan area. Resulting from the soil chemistry data, soil nitrogen contents seem to affect GHG emission from the tidal land surface. The tidal soil was found to be either source or sink for the major GHG during the experimental periods. The annual average of $CH_{4}\;and\;CO_{2}$ fluxes were $0.13{\pm}0.86\;mg\;m^{-2}h^{-1}\;and\;5.83{\pm}138.73\;mg\;m^{-2}h^{-1}$, respectively, which will be as a source of these gases. However, $N_{2}O$ emission showed in negative flux, and the value was $-0.02{\pm}0.66\;mg\;m^{-2}h^{-1}$, and it implies tidal land surface act as a sink of $N_{2}O$. Over the experimental period, the absolute values of gas fluxes increased with soil temperature in general. Averages of the ambient gas concentration were $86.8{\pm}6.\;ppm$ in $CO_{2},\;1.63{\pm}0.34\;ppm\;in\;CH_{4},\;and\;0.59{\pm}0.15\;ppm\;in\;N_{2}O$, respectively. Generally, under the presence of gas emission from agricultural soils, decrease of gas emission will be observed as increase in ambient gas concentration. We, however, could not found significant correlation between the ambient concentrations and their emissions over the experimental period. There was no GHG compensation points existed in tide flat soil.

• Journal of KIISE:Software and Applications
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• v.35 no.3
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• pp.197-206
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• 2008

In the mobile Internet environment, frequent communications between a mobile device and a content server are required for searching or downloading learning materials. In this paper, we propose an efficient prefetching technique to reduce the network cost and to improve the communication efficiency in the mobile dictionary. Our prefetching-based approach can be explained as follows. First, we propose an overall framework for the prefetching-based mobile dictionary. Second, we present a systematic way of determining the amount of prefetching data for each of packet-based and flat-rate billing cases. Third, by focusing on the English-Korean mobile dictionary for middle or high school students, we propose an intuitive method of determining the words to be prefetched in advance. Fourth, based on these determination methods, we propose an efficient prefetching algorithm. Fifth, through experiments, we show the superiority of our prefetching-based method. From this approach, we can summarize major contributions as follows. First, to our best knowledge, this is the first attempt to exploit prefetching techniques in mobile applications. Second, we propose a systematic way of applying prefetching techniques to a mobile dictionary. Third, using prefetching techniques we improve the overall performance of a network-based mobile dictionary. Experimental results show that, compared with the traditional on-demand approach, our prefetching based approach improves the average performance by $9.8%{\sim}33.2%$. These results indicate that our framework can be widely used not only in the mobile dictionary but also in other mobile Internet applications that require the prefetching technique.

• Membrane Journal
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• v.15 no.2
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• pp.114-120
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• 2005

The purpose of this study is to obtain practical information about membrane coupled $ A_2O$ system for muncipal wastewater treatment. A flat-plate microfiltration (MF) module with a pore size $0.25\;{\mu}m$ was submerged into the aeration basin and treated water was filtrated through the membrane by continuous suction with low pressure. The system was operated with synthetic wastewater to find operational parameters of internal recycle ratio and maximum MLSS showing best water quality and long-term stability. The internal recycle was defined as type 1 for aerobic to anoxic tank and type 2 for anoxic to anaerobic tank, respectively When the flux was maintained at $0.015\;m^3/m^2/hr$ (15 LMH) with 2Q type 1 internal recycle ratio, the optimal operational setting were 10 internal recycle ratio for type 2 and maximum MLSS of 11,000 mg/L among tested conditions. At this condition, removal efficiencies of BOD, CODcr, T-N and T-P showed $97.3\%,\;94.2\%,\;64.0\%,\;63.0\%$, respectively.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.10 s.352
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• pp.90-97
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• 2006

We report our research work on the millimeter-wave broadband amplifier integrating the shunt peaking technology with the cascode configuration. The millimeter-wave broadband cascode amplifier on MIMIC technology was designed and fabricated using $0.1{\mu}m\;{\Gamma}-gate$ GaAs PHEMT, CPW, and passive library. The fabricated PHEMT has shown a transconductance of 346.3 mS/mm, a current gain cut off frequency ($f_T$) of 113 GHz, and a maximum oscillation frequency ($f_{max}$) of 180 GHz. To prevent oscillation of designed cascode amplifier, a parallel resistor and capacitor were connected to drain of common-gate device. For expansion of the bandwidth and flatness of the gain, we inserted the short stub into bias circuits and the compensation transmission line between common-source device and common-gate device, and then their lengths were optimized. Also, the input and output stages were designed using the matching method to obtain the broadband characteristic. From the measurement, we could confirm to extend bandwidth and flat gain by integrating the shunt peaking technology with the cascode configuration. The cascode amplifier shows the broadband characteristic from 19 GHz to 53.5 GHz. Also, the average gain of this amplifier is about 6.5 dB over the bandwidth.

• The Korean Society of Law and Medicine
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• v.18 no.2
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• pp.195-218
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• 2017

The increase in medical expenses for convalescent hospitals is increasing abnormally, which puts enormous burden on the National health insurance finances. This is a phenomenon that has been associated with the social phenomenon of rapid aging. The fact that the convalescent hospitals are paid the fixed amount per day for hospitalization became the incentive for some hospitals to use the patients as means of making money. And these hospitals intend to get regular care or take medicines at other hospitals in order to reduce medical expenses, even when the medical fee is paid. In order to prevent such financial leaks, the Health Insurance Review and Assessment Service adjusted the patient group for inpatients in a hospital with the above behavior, and then cut the cost of medical care benefits. However, Above decision was canceled by the court on the grounds that there was no basis rule. However, based on the above case, I think that it can be an opportunity to draw up the problem and to improve of the Medical Fee System of hospital. The modified medical fee system can strengthen the medical function of the convalescent hospital. In addition, it seems reasonable to exclude admission for "physically disabled group". Even if admission is allowed for the physically disabled group due to social needs, it should be excluded from the National health insurance for the fianacial soundness and the sustainability of the system.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.12
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• pp.6191-6196
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• 2012

Aims and Background: Traditional chemotherapy strategies for human leukemia commonly use drugs based on cytotoxicity to eradicate cancer cells. One predicament is that substantial damage to normal tissues is likely to occur in the course of standard treatments. Obviously, it is urgent to explore therapies that can effectively eliminate malignant cells without affecting normal cells. Our previous studies indicated that ginsenoside $Rg_1$ ($Rg_1$), a major active pharmacological ingredient of ginseng, could delay normal hematopoietic stem cell senescence. However, whether $Rg_1$ can induce cancer cell senescence is still unclear. Methods: In the current study, human leukemia K562 cells were subjected to $Rg_1$ exposure. The optimal drug concentration and duration with K562 cells was obtained by MTT colorimetric test. Effects of $Rg_1$ on cell cycle were analyzed using flow cytometry and by SA-${\beta}$-Gal staining. Colony-forming ability was measured by colony-assay. Telomere lengths were assessed by Southern blotting and expression of senescence-associated proteins P21, P16 and RB by Western blotting. Ultrastructural morphology changes were observed by transmission electron microscopy. Results: K562 cells demonstrated a maximum proliferation inhibition rate with an $Rg_1$ concentration of $20{\mu}\;mol{\cdot}L^{-1}$ for 48h, the cells exhibiting dramatic morphological alterations including an enlarged and flat cellular morphology, larger mitochondria and increased number of lysosomes. Senescence associated-${\beta}$-galactosidase (SA-${\beta}$-Gal) activity was increased. K562 cells also had decreased ability for colony formation, and shortened telomere length as well as reduction of proliferating potential and arrestin $G_2$/M phase after $Rg_1$ interaction. The senescence associated proteins P21, P16 and RB were significantly up-regulated. Conclusion: Ginsenoside $Rg_1$ can induce a state of senescence in human leukemia K562 cells, which is associated with p21-Rb and p16-Rb pathways.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.3
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• pp.259-264
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• 2014

This paper is research paper on the MPD(Magnet Position Device) for the outdoor MGV(Magnet /Magnet Gyro Guidance Vehicle). Usually, MGV is used in indoor environment because of a measurement height of the magnet position device. CMPD(Commercial magnet position device) has 30 mm measurement height, so this is suitable structure in indoor environment like to a flat surface. Outdoor environment is an uneven and irregular, So Outdoor MGV must has a suspension. But CMPD is unsuitable for outdoor environment because of a collision with a surface caused by suspension. Thus, measurement height of the outdoor MPD is positively necessary more than 100 mm. So, we suggest the outdoor MPD using analog magnet hall sensor, moving average filter and Characteristic(rate of the magnet hall sensor) function of the localization. Result of the experiments, the proposed Magnet Position Device for the outdoor MGV has localization accuracy 4.31 mm, measurement height 150 mm and width 150 mm and is efficient more than CMPD.

• Journal of Wetlands Research
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• v.9 no.2
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• pp.21-31
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• 2007

Estuarine wetland, where freshwater meets saltwater, is a transitional ecosystem that is valuable ecologically for a variety of reasons, such as feeding and breeding sites for birds, fish, and wildlife. However, research on the spatial distribution and temporal dynamics of estuarine wetlands in Korea is rare. As a fundamental basis for wetland conservation, this study quantified the wetlands in three major estuaries, and evaluated the temporal dynamics of the wetlands since the 1910s. In particular, this study classified the wetland types into mud flat, sand, and emergent-plant types, and estimated the change of each wetland type, using topographic maps produced in the 1910s, 1970s, and 2000s. The wetlands in both the Han and Youngsan River estuaries have declined since the 1910s, but the rate of wetland decline was relatively low before the 1970s, compared to that since the 1970s. The impact of human activities, such as the Youngsan Watershed Comprehensive Development Project and the construction of estuary barrages, has disrupted the estuary cycles and destroyed huge amounts of wetland in the Youngsan estuary. By contrast, estuarine wetlands have been preserved in the small Gahwa estuary, and provide a variety of habitats for plants and wildlife. A special management strategy for wetlands should be established as soon as possible.