• The Journal of the Korea Contents Association
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• v.21 no.4
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• pp.678-687
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• 2021

Styrene is a commercially important chemical used mainly in the production of raw materials and plastics. To determine the effect of styrene on hepatic activities of antioxidant enzymes, styrene was treated to Sprague-Dawley rats at 50 mg/kg, 200 mg/kg and 400 mg/kg (i.p) twice a day for 4 days. There were determined the significantly increased activities of serum AST (aspartate aminotransferase), ALT (alanine aminotransferse), and the increased content of MDA (malondialdehyde) at the dose of 400 mg/kg compared to the control. The hepatic activities of XO (xanthine oxidase) and CYPdAH (cytochrome P450 dependant aniline oxidase) in the dose of 400 mg/kg compared to the dose of 200 mg/kg were more increased, which means the excessive ROS (reactive oxygen species)s were produced during Phase I. In addition, significantly decreased were rates of the hepatic activities of GPx (glutathione peroxidase), CAT (catalase), SOD (superoxide dismutase) and GST (glutathione S-transferase) at the dose of 400 mg/kg compared to the control. And, the group at the dose of 400 mg/kg showed more significantly decreased GSH (glutathione) level than the group at the dose of 200 mg/kg. The decrease in GSH could ascribe to the toxic metabolites of styrene, such as styrene oxide. In conclusion, these results indicate that the excessive ROSs and the toxic metabolites of styrene may result in the hepatotoxicity, and be related to their imbalanced activities for antioxidant enzymes.

• Korean Chemical Engineering Research
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• v.61 no.1
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• pp.58-61
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• 2023

The activation process is essential for PEMFC to improve initial performance. The most commonly used activation method is a voltage change (load change) method, which may accompany degradation of the electrode catalyst if excessively performed. In many activation processes, the voltage change range is activated in a wide range from 0.4 V to OCV, and research is needed to reduce the voltage change range in order to prevent electrode catalyst degradation and shorten the activation time. Therefore, in this study, when the activation voltage range was 0.4~0.6 V, 0.4~0.8 V, and 0.4~OCV, we tried to research and develop an effective activation method by analyzing the performance and characteristics of the electrode and polymer membrane. The performance improvement was the lowest in the activation with a wide voltage range from 0.4 V to the highest OCV, and the performance decreased by 10% when activated for 56 cycles. The 0.4~0.6 V activation cycle showed the highest performance improvement up to 20% and the smallest decrease in performance due to overactivation, indicating that it is optimal method.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.14 no.2
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• pp.229-237
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• 2003

Objectives：Among the studies related to excessive computer use, the studies for elementary school students are relatively rare. Because children have relatively poor ability to recognize and express themselves, the carers' information is important to assess the children. This study attempted to investigate the relationship between children's computer use and sociopsychiatric characteristics on the basis of carers' reports. Methods：The subjects of this study were 287 5th- and 6th-grade students in the elementary school in Seoul. The student carers were asked to answer the questions for children's computer use, the computer addiction test modified from Young's parent-child internet addiction test, Korean Personality Inventory for Children(K-PIC). SPSS(version 10) was used to analyse the differnece of computer use between genders and the relation of the computer addiction test with K-PIC. Results：1) The score of computer addiction test was significantly higher in male children than in female children and more male children compared to female children were distributed in the excessive user group. 2) The score of computer addiction test correlated with the scores of most clinical scales of K-PIC and the average scores of most clinical scale were significantly higher in the excessive user group than in the general user group. 3) More children with score above 65 in HPR, DLQ, FAM scale were distributed in excessive user group than in general user group. Conclusion：The 5th- and 6th-grade elementary school students with excessive computer use were found to show more sociopsychiatric problems. With these finding we suggest that social and clinical attention to the children who use computer excessively shoud be required.

• Journal of the Korea Convergence Society
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• v.9 no.4
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• pp.271-283
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• 2018

This study aimed to investigate the effect of adolescent development environment including parenting attitude, peer relationship, and school environment on delinquent behavior, and between these relationships, the mediate effect of media environment such as computer and mobile devices. The $6^{th}$ year data from Korean Children & Youth Panel Survey (KCYPS) was used and the subjects were limited to 518 students of $7^{th}$ grade who are in their early adolescence. The result shows that adolescents under more affectionate, over involvement, and abusive parenting attitude will commit delinquent behaviors more frequently, and so does alienated youth from their friends. Parenting inconsistency and communication with friends make them use computer and cell phone more often, and excessive media usage increases adolescent's delinquent behavior. In conclusion, family environment and peer relation have influence on adolescents' delinquent behavior. Therefore, there is necessity to build development environment that prevent adolescents' delinquencies like parent education program or peer communication program for example. Also, proper education program for using computer or cell phone usage can reduce adolescents' delinquent behaviors, especially when its addictive aspect was recently issued.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.4954-4961
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• 2010

Background: Competition among hospitals has intensified, because hospitals and beds are oversupplying and the global medical market has opened in Korea. Method: we developed questionnaires of the patient's satisfaction about 20 items. We surveyed 297 out-patients and 302 in-patients. We analyzed the descriptive statistics and regression by SPSS(Version 17) and Excel. Results: The relations with the patient's loyalty and the specialized hospital service are 1) Recommend to other person: FHR use and the assistant for follow-up treatment were related positively for out-patient and PHR and FHR use were related positively for out-patient. 2) Revisiting: PHR use and the need of an assistant for follow-up patients were related for them and the PayTV were negatively related. Conclusion: FHR, PHR and assistant system for follow-up patient's condition were very useful factors to increase patient's loyalty.

• Journal of Sericultural and Entomological Science
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• v.18 no.1
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• pp.27-39
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• 1976

In this study several kinds of spun silk yarn-synthetic filament compounded yarn was manufactured, and several fabrics woven from above mentioned silk compound yarn for evaluation of serviceability as clothing materials. The following results were obtained: 1. Degumming agents are in the order of sodium silicate, sodium hydroxide, sodium carbornate, soap and water. 2. When the concentration of sodium hydroxide is exceeded 3%, degradation of floss silk property is resulted because of excessive dissolving out of silk protein. 3. Degumming effect is much improved by concentration of degumming agent and less by its treating time. 4. Simultaneous application of more the 2 kinds of degumming agent is desirable for improvement of floss silk. 5. Application of natural organic acid brings very good results in keeping original scooping and color of the silk. 6. Load and elongation it increased by compound with synthetic filament yarn. 7. Even the evenness of compound yarn is largely dependent on the quality of floss silk and extent of degumming, the C.V.% of silk compound yarn in the experiment was 8-12%. 8. Single bath dyeing technique was impossible for their cloth, and dyeing was performed in 2 bath system separately for silk and synthetic fiber. 9. Shrinkage ratio due to the dyeing of fabric was 23% in case of polyester and spun silk fabric. 10. The final woven cloth can be applicable to (a) Blouse in care of thin cloth (compound silk fabric) (b) Korean costume for women in case of thick cloth. (compound hand spun silk fabric)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.166-175
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• 2017

This study examined children from two families exposed to domestic violence and had psychological counseling in July 2017 at KOVA, a support organization for crime victims. The subjects were exposed to family violence in excess of 10 years and was protected by the shelter with their mothers who had filed complaints with the local police. Victims of domestic violence often face difficulty in avoiding the source of aggression, and thus experience repetitive attacks. This research was conducted at the Buddhism Brain Research Facility, Seoul University, to identify and quantify the emotional characteristics of the affected children in which it is difficult to escape from their living conditions. Data was collected by BrainMaster, a 19-channel examination kit, and analyzed by NeuroGuide. As a result of analyzing the emotional characteristics of the affected children through Quantitative EEG and brain topographical map, we found an increase of slow wave and problems with abnormality of Alpha, High Beta in the left and right Frontal area asymmetry.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2826-2832
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• 2012

A smart grid is an electric-power grid that employs a new information technology.This technology makes it possible to exchange real-time energy information between suppliers and consumers, finally resulting in high energy efficiency. The energy management system in smart grid provides up to date information on electricity consumption as well as dynamic electricity price to consumers of smart grid system. However, the existing energy management systems only focus on pricing system, for example, real-time electricity prices. In this paper, we try to improve the existing energy management system and propose the energy management system that mainly focuses on the efficiency of electricity consumption. In the proposed management system, PMU(Phasor Measurement Units) installed in switchboards gathers electricity data in a real time. We also propose to use data mining method, which is applied to analyzed electricity data for improving energy efficiency. Also, the proposed energy management system is designed to efficiently control the electricity between PMU and management system in case of a shortage of electricity or surplus electricity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9A
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• pp.1372-1382
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• 1999

The major source of errors in high-speed networks such as Broadband ISDN(B-lSDN) is buffer overflow during congested conditions. These congestion errors are the dominant sources of errors in 1high-speed networks and result in cell losses. Conventional communication protocols use error detection and retransmission to deal with lost packets and transmission errors. However, these conventional ARQ(Automatic Repeat Request) methods are not suitable for the high-speed networks since the transmission delay due to retransmissions becomes significantly large. As an alternative, we have presented a method to recover consecutive cell losses using forward error correction(FEC) in ATM(Asynchronous Transfer Mode)networks to reduce the problem. The performance estimation based on the cell discard process model has showed our method can reduce the cell loss rate substantially. Also, the performance estimations in ATM networks by interleaving and IP multicast service are discussed.

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.141-146
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• 2012

A gene encoding the xylanase (XynA) predicted from partial genomic sequence of Paenibacillus woosongensis was cloned into Escherichia coli by PCR. This xynA gene consisted of 633 nucleotides, encoding a polypeptide of 211 amino acid residues. The deduced amino acid sequence exhibited 85-89% identity with those of several Paenibacillus xylanases, belonging to the glycosyl hydrolase family 11. As a results of expression of the structural gene by T7 promoter of a pET23a(+) expression vector, xylanase activity was higher in cell-free extract than culture filtrate of a recombinant Escherichia coli BL21(DE3) CodonPlus. However, the expression level of xylanase was not sufficient be detected by SDS-PAGE. The cell-free extract showed maximal xylanase activity at $60^{\circ}C$ and pH 5.5. The predominant products resulting from xylan and xylooligosaccharide hydrolysis were xylose and xylotriose. The enzyme could hydrolyze xylooligosaccharides larger than xylbiose.