• Geophysics and Geophysical Exploration
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• v.26 no.2
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• pp.62-76
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• 2023

Recently, machine learning (ML) techniques have been actively applied for seismic trace interpolation. However, because most research is based on training-inference strategies that treat missing trace gather data as a 2D image with a blank area, a sufficient number of fully sampled data are required for training. This study proposes trace interpolation using ML, which uses only irregularly sampled field data, both in training and inference, by modifying the training-inference strategies of trace-based interpolation techniques. In this study, we describe a method for constructing networks that vary depending on the maximum number of consecutive gaps in seismic field data and the training method. To verify the applicability of the proposed method to field data, we applied our method to time-migrated seismic data acquired from the Vincent oilfield in the Exmouth Sub-basin area of Western Australia and compared the results with those of the conventional trace interpolation method. Both methods showed high interpolation performance, as confirmed by quantitative indicators, and the interpolation performance was uniformly good at all frequencies.

• Composites Research
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• v.19 no.1
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• pp.29-35
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• 2006

The avoidance of enemy's radar detection is very important issue in the modem electronic weapon system. Researchers have studied to minimize reflected signals of radar. In this research, two types of radar absorbing structure (RAS), 'C'-type shell and 'U'-type shell, were fabricated using fiber-reinforced composite materials and their radar cross section (RCS) were evaluated. The absorption layer was composed of glass fiber reinforced epoxy and nano size carbon-black, and the reflection layer was fabricated with carbon fiber reinforced epoxy. During their manufacturing process, undesired thermal deformation (so called spring-back) was observed. In order to reduce spring-back, the bending angle of mold was controlled by a series of experiments. The spring-back of parts fabricated by using compensated mold was predicted by finite element analysis (ANSYS). The RCS of RAS shells were measured by compact range and predicted by physical optics method. The measured RCS data was well matched with the predicted data.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.1
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• pp.219-227
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• 2017

Current military command information system uses electronic equipment a lot on which semiconductor chip is attached. It seems its' importance will increase more with latest information communication technology developing. Electronic equipment which uses electricity contains regular tolerance to high output electric signal. And EMC specification is the standardized of this electronic equipment's tolerance. On the other hand, the Institute of Atomic Energy Research has ever declared that high output electromagnetic pulse(EMP) will be broken out within the radius of 170Km when 10kt nuclear explosion occurs at an altitude of 40Km above Seoul. Then, the region suffer from the damage of most electronic equipments. Therefore, the norm to protect the influences in that case is defined by EMP protection specification. Most common electronic equipments meet the EMC norm, but there is no way to check whether they meet the EMP norm or not. That is because it is difficult to check whether they meet EMP protection norm and is on the matter of cost. Except inevitable cases, there is no review of checking whether they meet the norm or not. Considering the above, in this research, we speculate about the measures to improve military EMP protection ability by analyzing the EMC-EMP correlation and checking the EMP protection ability of general electronic equipment through the analysis.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.2
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• pp.401-408
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• 2017

GNSS(Global Navigation Satellite System) is positioning and navigation system using satellites. Accurate positioning is possible in all regions of the world using satellite signals. In Korea, GPS was introduced in the late 1980s. GPS is used in research and work in various fields such as navigation, surveying, and GIS. Since 1995, NGII(National Geographic Information Institute) has installed and operated CORS(Continuously Operating Reference Station) for the practical use of GNSS surveying, RINEX download and VRS(Virtual Reference Station) service was provided for precise positioning. Demand for these services is explosively increasing in the field of surveying. Therefore, there is a need for research to provide good service. In this study, status of national surveying infra structure was researched focused on CORS and its services. As a results, current status of CORS and service were presented. Users of VRS service has increased greatly. In order to provide stable service and advanced surveying, it is necessary to continuously upgrade services such as providing services for various GNSS satellites and securing stability through server redundancy in the data center.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.1
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• pp.1-10
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• 2024

Purpose: Lycopene is abundantly contained in Tomatoes and is known for diverse biological activities such as antioxidant, anti-inflammatory, and anticancer effects. In this study, the antioxidative potential of lycopene was investigated through the induction of hemeoxygenase (HO)-1 by nuclear factor-erythroid 2 p45-related factor2 (Nrf2) and upstream signaling molecules, mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)/Aktin RAW 264.7 cells. Methods: The antioxidative potential of lycopene against oxidative stress and its molecular mechanisms were determined by the cell viability assay, intracellular reactive oxygen species (ROS) formation assay, and Western blot analysis in RAW 264.7 cells. Results: Lycopene treatment significantly attenuated tert-butyl hydroperoxide (t-BHP) induced intracellular ROS formation in a dose-dependent manner without any cytotoxicity. In addition, 50 µM of lycopene for 6 h treatment induced potent HO-1 expression and its transcription factor, Nrf2. MAPK and PI3K/Aktwere also analyzed due to their critical roles in the regulation of cellular redox homeostasis against oxidative damage. As a result, phosphorylation of extracellular regulated kinase (ERK) was significantly induced by lycopene treatment while the activated status of c-Jun NH2-terminal kinase (JNK), p38, and Akt, were not given any effect. To confirm the antioxidative mechanism of HO-1 mediated by ERK activation, each selective inhibitor was employed in a protection assay, in which oxidative damage occurred by t-BHP. Lycopene, SnPP, and CoPP treatments reflected accelerated HO-1 expression could be a protective role against oxidative damage-initiated cell death. A selective inhibitor for ERK significantly inhibited the lycopene-induced cytoprotective effect but selective inhibitors for other signaling molecules did not attenuate the rate of t-BHP-induced cell death. Conclusion: In conclusion, lycopene potently scavenged intracellular ROS formation and enhanced the HO-1 mediated antioxidative potential through the modulation of Nrf2, MAPK signaling pathway in RAW 264.7 cells.

• The Journal of the Acoustical Society of Korea
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• v.28 no.6
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• pp.572-577
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• 2009

Large corpus-based concatenating Text-to-Speech (TTS) systems can generate natural synthetic speech without additional signal processing. To prune the redundant speech segments in a large speech segment DB, we can utilize a decision-tree based triphone clustering algorithm widely used in speech recognition area. But, the conventional methods have problems in representing the acoustic transitional characteristics of the phones and in applying context questions with hierarchic priority. In this paper, we propose a new clustering algorithm to downsize the speech DB. Firstly, three 13th order MFCC vectors from first, medial, and final frame of a phone are combined into a 39 dimensional vector to represent the transitional characteristics of a phone. And then the hierarchically grouped three question sets are used to construct the triphone trees. For the performance test, we used DTW algorithm to calculate the acoustic similarity between the target triphone and the triphone from the tree search result. Experimental results show that the proposed method can reduce the size of speech DB by 23% and select better phones with higher acoustic similarity. Therefore the proposed method can be applied to make a small sized TTS.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.305-310
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• 2004

The present study was aimed at investigating effects of chicory inulin and three kinds of oligosaccharides on lipid metabolism in rats fed a high-cholesterol diet. Nine Sprague-Dawley male rats weighing, about 190g were given one of five experimental diets, which were basal cholesterol diet (Control) isomaltooligosaccharide diet (IMO), Iructooligosaccharide diet (FO), chicory inulooligosaccharide diet (CIO) and chicory inulin diet (CI) for 5 weeks. In the oligosaccharide and inulin diets, 6% was added at the expense of sucrose. Rats were pair-fed to the intake of FO group which consumed the least amount, and their feces were collected during the last 4 days. Body weight gain was lower in Fo and CI groups compared with the Control group. Plasma glucose levels of FO and CIO groups were lower and plasma triglyceride concentrations of FO, CIO, and CI groups were lower than those of IMO group. Plasma cholesterol concentration did not differ among groups. Relative liver weight was lower in CIO group. Hepatic triglyceride and cholesterol did not differ among. groups. Fecal excretion of neutral steroid and bile acid were not different among groups, but fecal triglyceride excretion was significantly increased in FO and CI groups compared with the Control group. In conclusion, supplementation of oligosaccharides and chicory inulin at 6% of diets showed no significant hypolipidemic effect in rats fed a high cholesterol diet.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.262-270
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• 2004

It is well known that long-term heavy ethanol intake causes alcoholic dementia, cerebellar degeneracy or Wernicke-Korsakoff syndrome and aggravates the conditions of many other neuro-psychotic disorders. Recently it is indicated that protein kinase C (PKC) plays an important role in the action of ethanol and in the neuro-adaptational mechanisms under chronic ethanol exposure. In order to investigate the effect of ethanol on PKC isoforms levels within the range of not showing any cytotoxicity, B103 neuroblastoma cell line trans-formed from murine central nervous system was employed and western blot analysis was carried out by using PKC isoform-specific antibodies. The changes of PKC-$\alpha$, ${\gamma}$, $\varepsilon$ and ζ level in the range of ethanol concentration 50∼200 mM were examined at the exposure time 1, 2, 8, 18 and 24 hrs in both cytosolic and membrane fraction. A typical ethanol concentration inducing the PKC isozymes was 100 mM, and the transforming time ranges of PKC isozymes could be considered as two different parts to each PKC isoform such as initial (0∼2 hrs) and prolonged (8∼24 hrs) stages. PKC-${\gamma}$ and PKC-$\varepsilon$ were clearly induced during the prolonged stages in cytosol at 18 hrs, and membrane fraction at 8 hrs and 18 hrs, respectively. On the other hand the PKC-$\alpha$ and PKC-ζ isozymes were largely induced in the prolonged stages at 18 hrs and 24 hrs, where the PKC-$\alpha$ isozyme was induced in both cytosol and membrane fractions at 200 mM ethanol concentration while the PKC-ζ isozyme was induced only in the membrane fractions at 100,200 mM. At 200 mM ethanol concentration of 24 hrs incubation in the prolonged stage, the PKC-$\alpha$ was maximally induced by 150% of the control values whereas the PKC-${\gamma}$ was significantly decreased to 47% of the control values. These results suggest that 100∼200 mM ethanol may modulate the signal transduction and neurotransmitter release in the central nervous system through the regulation of PKC isozymes, and the action of these isoforms may act differently each other in the cell.

• Journal of Plant Biotechnology
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• v.33 no.1
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• pp.1-9
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• 2006

Peroxiredoxins (Prxs) are ubiquitously distributed and play important functions in diverse cellular signaling systems. The proteins are largely classified into three groups, such as typical 2-Cys Prx, atypical 2-Cys Prx, and 1-Cys Prx, that are distinguished by their catalytic mechanisms and number of Cys residues. From the three classes of Prxs, the typical 2-Cys Prx containing the two-conserved Cys residues at its N-terminus and C-terminus catalyzes $H_2O_2$ with the use of thioredoxin (Trx) as an electron donor. During the catalytic cycle, the N-terminal Cys residue undergoes a peroxide-dependent oxidation to sulfenic acid, which can be further oxidized to sulfinic acid at the presence of high concentrations of $H_2O_2$ and a Trx system containing Trx, Trx reductase, and NADPH. The sulfinic acid form of 2-Cys Prx is reduced by the action of sulfiredoxin which requires ATP as an energy source. Under the strong oxidative or heat shock stress conditions, 2-Cys Prx in eukaryotes rapidly switches its protein structure from low-molecular-weight species to high-molecular-weight protein structures. In accordance with its structural changes, the protein concomitantly triggers functional switching from a peroxidase to a molecular chaperone, which can protect its substrate denaturation from external stress. In addition to its N-terminal active site, the C-terminal domain including 'YF-motif' of 2-Cys Prx plays a critical role in the structural changes. Therefore, the C-terminal truncated 2-Cys Prxs are not able to regulate their protein structures and highly resistant to $H_2O_2$-dependent hyperoxidation, suggesting that the reaction is guided by the peroxidatic Cys residue. Based on the results, it may be concluded that the peroxidatic Cys of 2-Cys Prx acts as an '$H_2O_2$-sensor' in the cells. The oxidative stress-dependent regulation of 2-Cys Prx provides a means of defense systems in cells to adapt stress conditions by activating intracellular defense signaling pathways. Particularly, 2-Cys Prxs in plants are localized in chloroplasts with a dynamic protein structure. The protein undergoes conformational changes again oxidative stress. Depending on a redox-potential of the chloroplasts, the plant 2-Cys Prx forms super-molecular weight protein structures, which attach to the thylakoid membranes in a reversible manner.

• Journal of Ginseng Research
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• v.31 no.4
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• pp.181-190
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• 2007

Compound K (CK), a protopanaxadiol ginsenoside metabolite, was previously shown to have immunomodulatory effects. In this study, we isolated the CK rich fractions (CKRF) from Korean Red Ginseng and investigated the regulation of CKRF-mediated inflammatory signaling during Toll-like receptor (TLR)-mediated cellular activation. Among various TLR ligands, CKRF considerably abrogated TLR4- or TLR9-induced inflammatory signaling. Both LPS and CpG-containing oligodeoxynucleotides (CpG-ODN) stimulation rapidly activates mitogen-activated protein kinases [MAPKs; extracellular signal-regulated kinases 1/2 and p38], NF-${\kappa}B$, and expression of pro-inflammatory cytokines tumor necrosis factor-${\alpha}$, and interleukin-6 in murine bone marrow-derived macrophages (BMDMs) in a time- and dose-dependent manner. Of interest, pre-treatment of CKRF in either LPS/TLR4- or CpG-ODN/TLR9-stimulated macrophages substantially attenuated the LPS-induced inflammatory cytokine production and mRNA expressions, as well as MAPK and NF-${\kappa}B$ activation. To our knowledge, this is the first description of the inhibitory roles for CKRF in TLR4- or TLR9-associated signaling in BMDMs. Collectively, these results demonstrate that CKRF specifically modulates distinct TLR4 and TLR9-mediated inflammatory responses, and further studies are urgently needed for their in vivo roles for potential therapeutic uses, such as in systemic inflammatory syndromes.