• Journal of Species Research
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• v.9 no.4
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• pp.346-361
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• 2020

In the project of a comprehensive investigation of indigenous prokaryotic species in Korea, a total of 39 bacterial strains phylogenetically belonging to the classes Betaproteobacteria and Gammaproteobacteria were isolated from various environmental sources such as soil, cultivated soil, sludge, seawater, marine sediment, algae, human, tree, moss, tidal flat, beach sand and lagoon. Phylogenetic analysis based on 16S rRNA gene sequences revealed that 39 strains showed the high sequence similarities (≥98.7%) to the closest type strains and formed robust phylogenetic clades with closely related species in the classes Betaproteobacteria and Gammaproteobacteria. In the present study, we report 14 species of 9 genera of four families of two orders in the class Betaproteobacteria and 25 species of 21 genera of 15 families of eight orders in the class Gammaproteobacteria, which have not been reported in Korea. Morphological, biochemical, and physiological characteristics, isolation sources, and NIBR deposit numbers are described in the species descriptions.

• Journal of Korean Society on Water Environment
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• v.22 no.1
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• pp.1-6
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• 2006

In this study, five commercially available fouling resistant low-pressure RO membranes were investigated for the treatment of seasonally brackish surface water with high organic content (${\approx}24mg/L$). The membranes investigated are LFC-1 (Hydranautics), X20 (Trisep), BW30FR1 (FilmTec), SG (Osmonics), and BE-FR (Saehan). The results of surface characterization revealed that each of these membranes has one or two unique surface characteristics to minimize the adherence of the fouling materials to the membrane. Specifically, the LFC1 membrane features a neutral or low negative surface to minimize electrostatic interactions with charged foulants. The X20, on the other hand, shows a highly negatively charged surface, and thus, is expected to perform well with feed waters containing negatively charged organics and colloids. The BW30FR1 exhibits a relatively neutral and hydrophilic surface, which could be beneficial for lessening organic and/or biofouling. The SG membrane has a smooth surface that makes it quite resistant to fouling, particularly for colloidal deposition. Lastly, BE-FR membrane demonstrated a medium surface charge and a slightly higher hydrophobicity. In the pilot study, all of the four membranes experienced a gradual increase in MTC (water mass transfer coefficient or specific flux) over time, indicating no fouling occurred during the pilot study. The deterioration of permeate water quality such as TDS was also observed over time, suggesting that the integrity of the membranes was compromised by the monochloramine used for biofouling control.

• Current Photovoltaic Research
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• v.1 no.1
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• pp.44-51
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• 2013

For preparing a device-quality $CuInSe_2$ (CISe) light-absorbing layer by single-bath electrodeposition for a superstrate-type CISe cell, morphological properties of the CISe layers were investigated by varying concentrations of sulfamic acid and potassium biphthalate, complexing/buffering agents. CISe films were grown on an $In_2Se_3$ film by applying a constant voltage of -0.5V versus Ag/AgCl for 90 min in a solution with precursors of $CuCl_2$, $InCl_3$, and $SeO_2$, and a KCl electrolyte. A dense and smooth layer of CISe could be obtained with a solution containing both sulfamic acid and potassium biphthalate in a narrow concentration range of combination. A CISe layer prepared on the $In_2Se_3$ film with proper concentrations of complexing/buffering agents exhibited thickness of $1.6{\sim}1.8{\mu}m$ with few undesirable secondary phases. On the other hand, when the bath solution did not contain either sulfamic acid or potassium biphthalate, a CISe film appeared to contain undesirable flake-shape $Cu_{2-x}Se$ phases or sparse pores in the upper part of film.

• Journal of Ginseng Research
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• v.40 no.1
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• pp.1-8
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• 2016

Background: Korean Red Ginseng (KRG) is a herbal medicine used in Asian countries and is very popular for its beneficial biological properties. Diabetes mellitus (DM) and its complications are rapidly becoming a global public health concern. The literature on transcriptional changes induced by KRG in rat models of diabetic retinopathy is limited. Considering these facts, we designed this study to determine whether retinopathy-associated genes are altered in retinas of rats with DM and whether the induced changes are reversed by KRG. Methods: Male Sprague-Dawley rats were intravenously injected with streptozotocin (50 mg/kg body weight) to induce DM, following which, KRG powder (200 mg/kg body weight) was orally administered to the KRG-treated DM rat group for 10 wks. The rats were then sacrificed, and their retinas were harvested for total RNA extraction. Microarray gene expression profiling was performed on the extracted RNA samples. Results: From among > 31,000 genes investigated, the expression of 268 genes was observed to be upregulated and that of 58 genes was downregulated, with twofold altered expression levels in the DM group compared with those in the control group. Moreover, 39 genes were upregulated more than twofold and 84 genes were downregulated in the KRG-treated group compared to the DM group. The expression of the genes was significantly reversed by KRG treatment; some of these genes were analyzed further to verify the results of the microarray experiments. Conclusion: Taken together, our data suggest that reversed changes in the gene expression may mediate alleviating activities of KRG in rats with diabetic retinopathy.

• Journal of the Korea Convergence Society
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• v.9 no.2
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• pp.289-294
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• 2018

A test study was conducted to identify the effects of diathermy through therapist's hand on patients with chronic lumbar pain. The study assessed the effectiveness of Winback High Frequency TECAR Therapy on 21 patients suffering from chronic lumbar pain and the testing was held at H Hospital and began in April 2016 and concluded in September 2016. Assessment of pain relief was through a Visual Analogue Scale (VAS) and the Oswestry Disability Questionnaire (ODQ). The results showed a VAS score decrease from $6.67{\pm}1.76$ to $5.52{\pm}2.03$ (p<0.05) and the ODQ results also showed an decrease from $41.19{\pm}2.56$ to $35.14{\pm}5.11$ (p<0.05). Both of these results are indicative of the positive effects that diathermy through therapist's hand has in the treatment of chronic pain, and the necessity for further studies in this field.

• Particle and aerosol research
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• v.13 no.4
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• pp.141-150
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• 2017

Using the NASA's Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2) reanalysis for aerosol optical depth (AOD) and satellite-observed carbon monoxide (CO) data, we examined the basic pattern of AOD variations over the three polar stations of Korea: Jangbogo and King Sejong stations in the Antarctica, and Dasan station in the Arctic area. AOD values at King Sejong and Dasan station show the maximum peaks in spring, which looks associated with the high amount of atmospheric CO emitted from the natural burning and the biomass burning. Jangbogo station shows the much less AOD compared to other two stations, and seems not strongly affected by the transport of airborne particles generated from mid-latitude regions. All three polar stations show the AOD increasing trend in general, indicating that the polar background air quality becomes polluted.

• Human Ecology Research
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• v.55 no.6
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• pp.649-659
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• 2017

This study investigated the effect of a child care center directors' work stress and awareness of their servant leadership on burnout. The subjects of this study were 200 child care center directors in Incheon. They responded to 'Work Stress Scale', 'Maslach Burnout Inventory (MBI)', 'Servant Leadership Scale'. There were five subscales of Servant Leadership Scale (altruistic calling, emotional healing, wisdom, persuasive mapping, and organizational stewardship). Data were analyzed by frequency, percentage, mean, standard deviation, Pearson's correlation and hierarchical regression. Moderating effects were examined using analysis procedures of Baron and Kenny. The major results were as follows. First, child care center directors' burnout and work stress were positively correlated. Child care center directors' burnout and awareness of their servant leadership (emotional healing, wisdom, persuasive mapping, and organizational stewardship) was negatively correlated. Second, child care center directors' work stress, emotional healing, persuasive mapping and organizational stewardship affected their burnout. This means that the work stress of child care center directors increases their burnout. However, the child care center director's servant leadership is a factor in reducing burnout. Third, child care center directors' work stress and organizational stewardship had an interaction effect on burnout. The results suggests that child care center directors' organizational stewardship needs to be considered as an important factor for decreasing their own burnout. We also discussed implications and suggestions for future research and policy makers.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.3
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• pp.627-637
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• 2015

As game item trading becomes more popular with the rapid growth of online game market, the market for trading game items by cash has increased up to KRW 1.6 trillion. Thanks to this active market, it has been easy to turn these items and game money into real money. As a result, some malicious users have often attempted to steal other players' rare and valuable game items by using their account. Therefore, this study proposes a detection model through analysis on these account thieves' behavior in the Massive Multiuser Online Role Playing Game(MMORPG). In case of online game identity theft, the thieves engage in economic activities only with a goal of stealing game items and game money. In this pattern are found particular sequences such as item production, item sales and acquisition of game money. Based on this pattern, this study proposes a detection model. This detection model-based classification revealed 86 percent of accuracy. In addition, trading patterns when online game identity was stolen were analyzed in this study.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.6
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• pp.1527-1537
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• 2016

As increasing of smartphone penetration over the world, various mobile payment services have been emerged and fraud transactions have drastically increased. Although many financial companies have deployed security solutions to detect fraud transactions in on/off-line environment, mobile payment services still lack fraud detection solutions and researches. The mobile payment is mainly comprised of micro-payments and payment environment is different from other payments, so mobile-specialized fraud detection is needed. In this paper, we propose a FDS (Fraud Detection System) based on data mining for mobile payment services. The method of this paper is applied to the real data provided by a PG (Payment Gateway) company in Korea. The proposed FDS consists of two phases; (1) the first phase is focused on classifying transactions at high speed (2) the second is designed to detect abnormal transactions with high accuracy. We could detect 13 transactions per second with 93% accuracy rate.

• Korean Journal of Agricultural Science
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• v.43 no.3
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• pp.415-423
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• 2016

This study was carried out to obtain basic data for the industrial use of Weissella koreensis and Lactobacillus sakei. The antibacterial activity of supernatants obtained from W. koreensis and L. sakei were tested against pathogenic bacteria such as Escherichia coli KCCM 11234, Salmonella enteritidis KCCM 3313, Salmonella enteritidis KCCM 12021, Salmonella typhimurium KCCM 40253, and Salmonella typhimurium KCCM 15. The supernatant of L. sakei showed antibacterial activity against E. coli KCCM 11234, S. enteritidis KCCM 12021, and S. typhimurium KCCM 15, while the supernatant of W. koreensis showed antibacterial activity against E. coli KCCM 11234 and S. enteritidis KCCM 12021. The effect of pH changes and heat treatment on antibacterial activity of the supernatants was examined using the sensitive pathogenic bacteria (E. coli KCCM 11234, S. enteritidis KCCM 12021 and S. typhimurium KCCM 15). Antibacterial activity against sensitive pathogenic bacteria was maintained under heat treatment at all temperatures, but there was no antibacterial activity associated with pH modification. Furthermore, it was confirmed that the antibacterial activity of the supernatants obtained from W. koreensis and L. sakei was a result of organic acids including, lactic, acetic, phosphoric, succinic, pyroglutamic, citric, malic, and formic acids. Therefore, the present study showed that the organic acids produced by L. sakei and W. koreensis exhibited a strong antibacterial activity against pathogenic bacteria. Moreover, in the food industry, these organic acids have the potential to inhibit the growth of pathogenic bacteria and improve the quality of stored food.