• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11B
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• pp.980-990
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• 2004

In this paper, we propose the dynamic bandwidth allocation algorithm for the IEEE802.3ah Ethernet Passive Optical Network(EPON) system to provide the fairness among terminals, and evaluate the delay-throughput performance by simulation. For the conventional EPON systems, an Optical Line Termination (OLT) schedules the upstream bandwidth for each Optical Network Unit (ONU), based on its buffer state. This scheme can provide a fair bandwidth allocation for each ONU. However, it has a critical problem that it does not guarantee the fair bandwidth among terminals which are connected to ONUs. For an example, we assume that the traffic from a greedy terminal increases at a time. Then, the buffer state of its ONU is instantly reported to the OLT, and finally the OW can get more bandwidth. As a result, the less bandwidth is allocated to the other ONUs, and thus the transfer delay of terminals connected to the ONUs gets inevitably increased. Noting that this unfairness problem exists in the conventional EPON systems, we propose a fair bandwidth allocation scheme by OLT with considering the buffer state of ONU as welt as the number of terminals connected it. For the performance evaluation, we develop the EPON simulation model with SIMULA simulation language. From the result of the throughput-delay performance and the dynamics of buffer state along time for each terminal and ONU, respectively, one can see that the proposed scheme can provide the fairness among not ONUs but terminals. Finally, it is worthwhile to note that the proposed scheme for the public EPON systems might be an attractive solution for providing the fairness among subscriber terminals.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.4 s.48
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• pp.439-444
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• 2004

UV irradiation produces free radicals and related reactive oxygen species (ROS), and these are injury to all most of organisms of skin cells and extracellular matrix (ECM). In addition, free radicals and ROS stimulate the overexpression of matrix metalloproteinases (MMPs) that can degrade most components of ECM such as collagen. Since collagen constitutes almost of skin connective tissue, their disarrangement causes wrinkle formation and droop of skin. Therefore, scavenging activity on free radicals, ROS and suppression of MMP-1 is expected to prevent skin photoaging. In this study, to investigate the relationship between photoaging and Draconis sanguis, we examined the effects of antioxidant, in vitro MMP inhibition and expression of UVA-induced MMP-1 in human dermal fibroblasts. Draconis sanguis was found to show scavenging activities of radicals and ROS with the $IC_{50}$ values of $183{\;}{\mu}g/mL$ against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and $30{\;}{\mu}g/mL$ against superoxide radicals in the xanthine/xanthine oxidase system, respectively. Draconis sunguis inhibited the activities of MMP-1 in a does-dependent manner and the $IC_{50}$ value calculated from semi-log plots was $200{\;}{\mu}g/mL$. Also, UVA induced MMP expression was reduced $74\%$ by treatment with Draconis sanguis, and MMP-1 mRNA expression was reduced in a dose-dependent manner. Therefore Draconis sanguis was able to significantly inhibit MMP expression in protein and mRNA level. All these results suggested that Draconis sanguis may act as an anti-photoaging agent by antioxidation and reducing UVA-induced MMP-1 production.

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.17-28
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• 2018

In this study, catalytic activation using sulfuric acid lignin (SAL), the condensed solid by-product from saccharification process, with potassium hydroxide at $750^{\circ}C$ for 1 h in order to investigate its potential to nanoporous carbon In this study, catalytic activation using sulfuric acid lignin (SAL), the condensed solid by-product from saccharification process, with potassium hydroxide at $750^{\circ}C$ for 1 h in order to investigate its potential to nanoporous carbon material. Comparison study was also conducted by production of activated carbon from coconut shell (CCNS), Pinus, and Avicel, and each activated carbon was characterized by chemical composition, Raman spectroscopy, SEM analysis, and BET analysis. The amount of solid residue after thermogravimetric analysis of biomass samples at the final temperature of $750^{\circ}C$ was SAL > CCNS > Pinus > Avicel, which was the same as the order of activated carbon yields after catalytic activation. Specifically, SAL-derived activated carbon showed the highest value of carbon content (91.0%) and $I_d/I_g$ peak ratio (4.2), indicating that amorphous large aromatic structure layer was formed with high carbon fixation. In addition, the largest changes was observed in SAL with the maximum BET specific surface area and pore volume of $2341m^2/g$ and $1.270cm^3/g$, respectively. Furthermore, the adsorption test for three kinds of organic pollutants (phenol, 2,4-Dichlorophenoxyacetic acid, and carbofuran) were conducted, and an excellent adsorption capacity more than 90 mg/g for all activated carbon was determined using 100 ppm of the standard solution. Therefore, SAL, a condensed structure, can be used not only as a nanoporous carbon material with high specific surface area but also as a biosorbent applied to a carbon filter for remediation of organic pollutants in future.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.1
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• pp.68-76
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• 2017

Antioxidative capacities of Stachys sieboldii MIQ and 6-year-old ginseng powder were assessed after extraction with 80% ethanol, and their addition effects on quality characteristics of cookies were determined. Stachys sieboldii MIQ showed 3.12-fold higher total phenol content (TPC) and higher antioxidative capacities than ginseng based on higher values of 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity, ferric reducing antioxidant capacity, and Trolox equivalent antioxidant capacity (P<0.05). The 80% ethanol extract was then fractionated with $H_2O$ (Fr. I), 30% (II), 50% (III), 70% (IV), and 100% ethanol (V). Fractions of Stachys sieboldii MIQ extract showed 2.2-fold (Fr. I)~6.1-fold (III) higher TPC and higher antioxidative capacities than ginseng extract fractions. TPC was in the order of fractions III> II> I> IV> V for Stachys sieboldii MIQ extract while in the order of fractions I~III> IV~V for ginseng extract, assuming that Stachys sieboldii MIQ contained more phenolic compounds with higher polarity than ginseng. Addition of 5% and 10% Stachys sieboldii MIQ and ginseng powder increased spread ratio in cookies compared to 100% wheat flour, and 10% addition of Stachys sieboldii MIQ resulted in the darkest and most reddish cookies. In the sensory evaluation, cookies with 5% and 10% Stachys sieboldii MIQ received higher scores for taste preference and higher overall acceptability than ginseng or control cookies. Therefore, powder of Stachys sieboldii MIQ could impart more favorable sensory characteristics as well as higher antioxidative capacity than ginseng in bakery products.

• Journal of the Korean Ceramic Society
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• v.39 no.6
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• pp.550-557
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• 2002

TiO$_2$ particles coated on fly ash composites for use in photocatalyst were synthesized by the precipitation dropping method and heated at $700^{\circ}C$ for 2 h. The pH of reaction solution, the addition rate of NH$_4$HCO$_3$, the stirring speed, the reaction temperature and the concentration of TiC1$_4$ had a pronounced effect on the nature of precipitated TiO$_2$ particles on the surface off fly ash and the crystal structure of precipitated TiO$_2$ particles. At an addition rate of NH$_4$HCO$_3$; 1.0 ml/min, the pH of the reaction solution; 6, the stirring speed; 1,000 rpm and the reaction temperature; 8$0^{\circ}C$, about 10 nm of TiO$_2$ particle size and homogeneous precipitated layer on the surface of a fly ash was achieved. On the contrary, at an addition rate of NH$_4$HCO$_3$; 0.3,0.5 ml/min, the pH of the reaction solution; 2 and 11, the stirring speed; 300~500 rpm and the reaction temperature; lower than 5$0^{\circ}C$:, Inhomogeneous precipitated layer was developed on a fly ash. TiO$_2$ particles with anatase phase was formed as-dried precipitation at the low concentration of Tic14, the high addition rate of NH$_4$HCO$_3$ and the high reaction temperature, the crystalline fraction of anatase increased with raising heat-treatment temperature and rutile phase began to formation at 80$0^{\circ}C$. The crystal size of TiO$_2$ particles increased with raising the heat-treatment temperature, the crystal size was showed about 21 m at $700^{\circ}C$. Anatase type of TiO$_2$ coated on the fly ash heated at $700^{\circ}C$ for 2 h showed 1.25 g/cm$^3$of particle density, 82.8% of strength and 69.5 Lab of whiteness and can be used as a photocatalyst.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5C
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• pp.664-672
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• 2004

Widespread popularity of wireless data communication devices, coupled with the availability of higher bandwidths, has led to an increased user demand for content-rich media such as images and videos. Since such content often tends to be private, sensitive, or paid for, there exists a requirement for securing such communication. However, solutions that rely only on traditional compute-intensive security mechanisms are unsuitable for resource-constrained wireless and embedded devices. In this paper, we propose a selective partial image encryption scheme for image data hiding , which enables highly efficient secure communication of image data to and from resource constrained wireless devices. The encryption scheme is invoked during the image compression process, with the encryption being performed between the quantizer and the entropy coder stages. Three data selection schemes are proposed： subband selection, data bit selection and random selection. We show that these schemes make secure communication of images feasible for constrained embed-ded devices. In addition we demonstrate how these schemes can be dynamically configured to trade-off the amount of ded devices. In addition we demonstrate how these schemes can be dynamically configured to trade-off the amount of data hiding achieved with the computation requirements imposed on the wireless devices. Experiments conducted on over 500 test images reveal that, by using our techniques, the fraction of data to be encrypted with our scheme varies between 0.0244％ and 0.39％ of the original image size. The peak signal to noise ratios (PSNR) of the encrypted image were observed to vary between about 9.5㏈ to 7.5㏈. In addition, visual test indicate that our schemes are capable of providing a high degree of data hiding with much lower computational costs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.10
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• pp.1560-1566
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• 2013

This study was conducted to find out the effects of aqueous extract from the leaves of Artemisia capillaris (AA) on the reduction of hepatotoxicity induced by ethanol in rats. In this experiment, Sprague Dawley rats were used in the experimental groups, which were divided into 5 groups; normal group, ethanol+UDCA (ursodeoxycholic acid)-treated group (positive control), ethanol-treated group (control), ethanol+Artemisia capillaris aqueous extract-treated group (200 mg/kg of BW) and ethanol+Artemisia capillaris aqueous extract-treated group (400 mg/kg of BW). AST (aspartate aminotransferase), ALT (alanine aminotransferase), GGT (gamma(${\gamma}$)-glutamyl transferase) and LDH (lactate dehydrogenase) activities of the ethanol+Artemisia capillaris aqueous extract-treated group (400 mg/kg of BW) were significantly decreased compared to that of the ethanol-treated group (P<0.05). The triglyceride level of the ethanol-treated group was significantly increased and the HDL-cholesterol level was significantly decreased compared to the normal group (P<0.05). On the other hand, the triglyceride level was significantly decreased (P<0.05) and the HDL-cholesterol level was significantly increased (P<0.05) in the ethanol+Artemisia capillaris aqueous extract-treated groups. Superoxide dismutase (SOD) activity was enhanced significantly (P<0.05) in the ethanol+Artemisia capillaris aqueous extract-treated groups. Also, malondialdehyde contents were decreased in this group (P<0.05). Histologically, in the control group, there was a mild degenerative change around central venule. The AA treated group showed well preserved lobular architectures with no evidence of steatosis or liver damage in aqueous extract from the leaves of Artemisia capillaris treated group (H&E, ${\times}20$). As the results of this study, it is thought that Artemisia capillaris aqueous extract may have effects on the improvement of hepatic damage by ethanol.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.2
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• pp.185-195
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• 2017

Two byproducts, brewer's spent grain (BSG; germinated rice and malt) and brewer's spent material (BSM; Achyranthes japonica Nakai), were collected during the manufacture of pilsner beer using A. japonica Nakai and germinated rice. Water extracts of BSG and BSM were prepared at different temperatures ($25^{\circ}C$, $60^{\circ}C$, and $100^{\circ}C$) for 5 h, and their nutritional and functional properties were investigated. ${\gamma}-Aminobutyric$ acid (GABA), saponin, and niacin contents were higher in extracts prepared at $60^{\circ}C$ for more than 3 h than the other extracts, whereas total polyphenol content, DPPH radical scavenging activity, and reducing power were higher in samples extracted at $100^{\circ}C$ for 1 h compared to the other ones. Overall, water extraction at $60^{\circ}C$ for 3 h was desirable to effectively collect both nutritional and functional components from BSG and BSM. Under these conditions, BSM extracts showed 4~18 times high niacin and folate contents, 1.4 times high total phenolic content, and 11~60 times high antioxidant activities compared to BSG extracts. This study shows that pilsner beer byproducts would be good sources of health beneficial components, especially GABA, saponin, water soluble vitamins, and polyphenolics.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.349-355
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• 2014

This study was performed to evaluate influences of tunnel covering materials and seeding dates on the growth and productivity of water spinach (Ipomoea aquatic F.) cultured early in unheated greenhouse. During tunnel installation period, from March 5 to April 30 and from October 11 to November 10, air and soil temperature in tunnel covered with polyethylene film (PEF) had risen $2.0-2.4^{\circ}C$ and $0.9-1.0^{\circ}C$, respectively, compared to those in non-tunnel (NT). Air and soil temperature in tunnel with illite non-fabric (INF) also had risen $1.6-1.8^{\circ}C$ and $0.6-0.8^{\circ}C$, respectively. Especially, it showed greater effects of the rise at low temperature time zones of the day. In plots of seeding on March 15 in tunnel covered with PEF or INF, temperature during emergence period, emergence days and rate were similar to plot seeding on April 5 in NT. There were two more harvesting in plots of seeding on March 5 or March 15 in tunnel, and increasing of total yield by 22.5-25.7% compared to plot of seeding on April 5 in NT. But there was observed no significant differences between PEF and INF. Whereas PEF was necessary to be removed at midday sometimes because it had risk of high temperature injury, INF was not necessary. All above suggest that it was suitable to sow seed on the middle of March in tunnel covered with INF, for early culture of water spinach in unheated greenhouse.

• Korean journal of food and cookery science
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• v.24 no.6
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• pp.742-747
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• 2008

This study was performed to evaluate the quality characteristics of the hamburger patty to which Chungkukjang powder (CJP; 0, 2, 4, and 6%) had been added. The contents of moisture, crude protein and crude ash in the control group(0%) were significantly(p<0.01) lower than that of the CJP patties, but crude lipid content in the control group was significantly (p<0.01) higher than that of the treated group. The values of L(brightness) and b(yellowness) of the control group were lower than that of the CJP patties, but a-value(redness) of the control group exhibited the highest score. The texture of the control group was significantly(p<0.05) harder than that of the CJP patties. Among the mean scores of sensory characteristics of samples, the patty with 2% CJP powder showed the highest sensory score, and also, had significantly(p<0.05) higher chewiness than the control group. In preference, the control group showed a higher score than the treated group, but this difference was not statistically significant. The patty with 2% CJP had significantly (p<0.01) higher consumer sensory score in texture than that of markets. The results showed that the CJP patties could contribute toward complementing the nutrients of hamburgers on sale. Furthermore, the results of this study can contribute toward improving the nutritional and functional well-being of products.