• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.4
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• pp.21-28
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• 2006

In this paper, the proposed full-bridge high frequency isolated zoo voltage and zero current switching phase shifted pulse width modulation(ZVZCS PS-PWM)DC-DC converter among fuel cell generation system consist of 1.2[kW] fuel cell of Nexa Power Module, full-bridge DC-DC converter to boost the fuel cell low voltage($28{\sim}43[%]$) to 380[VDC] and a single phase full-bridge inverter is implemented to produce AC output(220[VAC], 60[Hz]). A tapped inductor filter with freewheeling diode is newly implemented in the output filter of the proposed full-bridge high frequency isolated ZVZCS PS-PWM DC-DC converter to suppress circulating current under the wide output voltage regulation range, thus to eliminate the switching and transformer turn-on/off over-short voltage or transient phenomena. Besides the efficiency of $93{\sim}97[%]$ is obtained over the wide output voltage regulation ranges and load variations.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.5
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• pp.976-988
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• 2002

The aim of this study was to examine the memory and attention enhancement effect of YMG-1 and YMG-2, which are modified herbal extracts from Yukmijihwang-tang (YMJ). YMJ, composing six herbal medicine, has been used for restoring the normal functions of the body to consolidate the constitution, nourishing and invigorating the kidney functions for hundreds years in Asian countries. A series of studies reported that YMJ and its components enhance memory retention, protects neuronal cell from reactive oxygen attack and boost immune activities. Recently the microarray analysis suggested that YMG-1 protects neurodegeneration through modulating various neuron specific genes. A total of 55 subjects were divided into three groups according to the treatment of YMG-1 (n=20), YMG-2 (n=20) and control (C; n=15) groups. Before treatments, all of subjects were subjected to the assessments on neuropsychological tests of K-WAIS test, Rey-Kim memory test, and psychophysiological test of Event-Related Potential (ERP) during auditory oddball task and repeated word recognition task. They were repeatedly assessed with the same methods after drug treatment for 6 weeks. Although no significant effect of drug was found in Rey-Kim memory test, a significant interaction (P = .010, P < 0.05) between YMG-2 and C groups was identified in the scores digit span and block design, which are the subscales of K-WAIS. The very similar but marginal interaction (P = .064) between YMG-1 and C groups was found too. In ERP analysis, only YMG-1 group showed decreasing tendency of P300 latency during oddball task while the others tended to increase, and it caused significant interaction between session and group (p= .004). This result implies the enhancement of cognitive function in due to consideration of relationship between P300 latency and the speed of information processing. However, no evidence which could demonstrate the significant drug effect was found in neither amplitude or latency. These results come together suggest that YMG-1, 2 may enhance the attention, resulting in enhancement of memory processing. For elucidating detailed mechanism of YMG on learning and memory, the further studies are necessary.

• Journal of the Korean Society of Radiology
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• v.5 no.5
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• pp.267-275
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• 2011

The purpose of this study was to examine the impact of the professional burnout and job autonomy of radiologic technologists on their turnover intention in hospitals. The major findings of the study were as follows: As for the average and standard deviation of the radiologic technologists in professional burnout and job autonomy, they got a mean of 3.15 in overall professional burnout, which was above the average. They got 2.88 in job autonomy, which was below the average. And they got 3.30 in turnover intention, which indicated that they had a strong tendency to change jobs. Regarding the influential factors for turnover intention, emotional burnout, loss of interest and loss of enthusiasm were identified as the factors that exerted a significant influence on turnover intention. If the kind of environments that stimulate their professional enthusiasm and allow them to make a decision on radiographic examinations based on their own professional knowledge is created, their burnout will be minimized. And the development of programs geared toward bolstering their job autonomy is expected to weaken their turnover intention, to enhance the efficiency of the personnel administration of radiologic technologists and their qualifications, and ultimately to boost their status in hospital organizations.

• The Korean Journal of Pesticide Science
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• v.16 no.1
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• pp.11-20
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• 2012

As increasing the use of pesticides both in number and amount to boost crop production, consumer concerns over food quality and safety with respect to residual pesticides are also continuously increasing. However, there is still lacking of information that can effectively help to remove residual pesticides in foods. In recent years, contaminant removal by gas (or) glow discharge plasma (GDP) attracts great interests on environmental scientists because of its high removal efficiency and environmental compatibility. It was shown to be effective for the removal of some organophosphorus pesticides, phenols, benzoic acid, dyes, and nitrobenzene on solid substrate or in aqueous solution. This work mainly focuses on the removal of wide range of residual pesticides from fresh fruits and vegetables. As for preliminary study, the experiments were carried out to investigate whether GDP can be used as an effective tool for degrading target pesticides or not. With this objective, 60 selected pesticides drop wised onto glass slides were exposed to two types of GDP, dielectric barrier discharge plasma (DBDP) and low pressure discharge plasma (LPDP), for 5 min. Then, they were washed with 2 mL MeCN which were collected and used for determination of remaining concentration of pesticides using LC-MS/MS. Among selected pesticides, degradation of 18 pesticides (endosulfan-total was counted as one pesticide) by GDP could not be examined because control treatments, which were left in ambient environment, of those pesticides recovered less than 70% or even did not recover. However, majority of tested pesticides (42) were degraded by both types of GDP with satisfactory recovery (>80%) of control sample. Pesticides degradation ranged from 66.88% to 100% were achieved by both types of plasma except clothianidin which degradation in LPDP was 26.9%. The results clearly indicate that both types of gas discharge plasma are promising tools for degrading wide range of pesticides on glass substrate.

• Radiation Oncology Journal
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• v.31 no.2
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• pp.104-110
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• 2013

Purpose: Intensity modulated arc therapy (IMAT) is a form of intensity modulated radiation therapy (IMRT) that delivers dose in single or multiple arcs. We compared IMRT plans versus single-arc field (1ARC) and multi-arc fields (3ARC) IMAT plans in high-risk prostate cancer. Materials and Methods: Sixteen patients were studied. Prostate ($PTV_P$), right pelvic ($PTV_{RtLN}$) and left pelvic lymph nodes ($PTV_{LtLN}$), and organs at risk were contoured. $PTV_P$, $PTV_{RtLN}$, and $PTV_{LtLN}$ received 50.40 Gy followed by a boost to $PTV_B$ of 28.80 Gy. Three plans were per patient generated: IMRT, 1ARC, and 3ARC. We recorded the dose to the PTV, the mean dose ($D_{MEAN}$) to the organs at risk, and volume covered by the 50% isodose. Efficiency was evaluated by monitor units (MU) and beam on time (BOT). Conformity index (CI), Paddick gradient index, and homogeneity index (HI) were also calculated. Results: Average Radiation Therapy Oncology Group CI was 1.17, 1.20, and 1.15 for IMRT, 1ARC, and 3ARC, respectively. The plans' HI were within 1% of each other. The $D_{MEAN}$ of bladder was within 2% of each other. The rectum $D_{MEAN}$ in IMRT plans was 10% lower dose than the arc plans (p < 0.0001). The GI of the 3ARC was superior to IMRT by 27.4% (p = 0.006). The average MU was highest in the IMRT plans (1686) versus 1ARC (575) versus 3ARC (1079). The average BOT was 6 minutes for IMRT compared to 1.3 and 2.9 for 1ARC and 3ARC IMAT (p < 0.05). Conclusion: For high-risk prostate cancer, IMAT may offer a favorable dose gradient profile, conformity, MU and BOT compared to IMRT.

• Land and Housing Review
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• v.5 no.2
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• pp.57-68
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• 2014

As social needs are increasing to minimize the occurrence of external effect due to urban development and to diffuse the benefits of development to surrounding areas, diverse cooperative planning methods are increasingly being discussed. In the long term, laws and systems need to be refined to support cooperative planning, but prior to such development, elements, procedures, and methodologies wherein cooperative planning in U.S.A cases could be implemented were examined to derive the alternative to and implications of cooperative planning that can apply not only to single administrative districts but also to complex boundary new towns being developed by various local governments. This paper surveyed and analyzed the cases of Wisconsin State of the U.S.A, thereby deriving the following implications. First, joint planning areas should be established within the boundary area of various local governments to establish cooperative planning areas in special areas such as complex boundary new towns, and to this end, urban planning means should be prepared. Together with such efforts, to boost the flexibility of cooperative planning, life sphere unit-based planning unit should be established, and a well-organized operation system to activate communities should be prepared. Also, revenues, generated through regional growth, should be distributed to individual local governments through joint tax according to the agreed-upon ratios, and as such, measures to share services and operate joint tax in small-size regions should be secured. Together with such efforts, to establish cooperative governance, measures to manage conflicts through the participation by stakeholders and arbitrators should be prepared from the planning stage, and measures for implementing cooperative planning at the level of basic urban planning should be prepared.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2036-2047
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• 2014

Now that there is no more barrier in terms of the global countries, every country begins to show its interest in the regional industry in order to boost local growth and economy revitalization preparing for the globalization, the age of limitless competition and the age of knowledge economy. The reason of the interesting in the regional industry is that it fosters the profitable environment that promotes technical innovation and knowledge creation. The local government should have continual concern and roles to fulfil the political subjects and keep analysing about the possibility that there could be the sustainable development by Task Ahead of the local industry. for this reason, this paper conducted a survey by targeting supported corporations's experience of supporting projects in the regional industry and the relationship impact of supporting projects in the regional industry. the elements are analyzed by PLS structural equation. To sum up, first, the improving of 'infrastructure Usage', 'Technical development', 'Marketing support', 'Attraction of investment', 'Manpower training' is impacted on Industrial development. Second, the improving of 'Joint research', 'Technology transfer', 'Attraction of investment', 'Manpower training', 'Networking ' is impacted on Regional development. Third, improving of Industrial development is impacted on Regional development.

• Journal of Internet Computing and Services
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• v.16 no.4
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• pp.1-11
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• 2015

This study uses the contingent valuation method to estimate the switching cost for adopting the MVNO service. The findings are as follows.: First, Willingness To Switch(WTS) increases as users' using pattern and perceived degree of MVNO service, but satisfaction with current service provider does not play a significant role in predicting Switching Cost. This means that as amount of money users can save exceeds a certain level, users decide to willingly change their service provider to MVNO regardless of their level of satisfaction with current service provider. Second, there are differences in WTS among service subscribers in SKT, KT and LGU+. It means that there will be a difference in the tendency to switch to MVNO among subscribers of service providers. This study suggest the following mangerial perspective to effectively promote the MVNO and boost the MVNO market for activation of mobile data services.: First, MVNOs are better off applying differentiated pricing scheme at attractive rates than using a differentiation of service product and quality. Second, regulators should consider how to implement an MVNO regulatory policy when there is an asymmetric customer loyalty among MNOs. This research will be used to set the MVNO's pricing strategy and to build up a successful regulatory policies.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.280-287
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• 2015

Probiotics are microbial food supplements or components of bacteria which have traditionally been added to dairy foods for extra health boost. Our aim was to evaluate the hepatoprotective effect of Bifidobacterium adolescentis SPM0212 as probiotics, which we previously found has potential anti-hepatitis B virus activity. The study was conducted using Wistar albino rats and probiotics were treated orally for 9 days consecutively and acute liver injury was induced by administration of carbon tetrachloride ($CCl_4$) on the 7th and 8th days. Liver damage was assessed by quantifying serum activities of glutamate oxaloacetate transaminase (SGOT) and glutamate pyruvate transaminase (SGPT), as well as by histopathological examination. B. adolescentis SPM0212 significantly prevented the elevation of SGOT and SGPT levels, and reduced the negative effect of $CCl_4$ on body and organ weights. Histopathological study revealed the livers of the carbon tetrachloride treated rats showed almost complete loss of normal hepatocyte architecture, but that rats treated with B. adolescentis SPM0212 showed minimal damage and normal hepatocyte architecture. Our results suggest that B. adolescentis SPM0212 be considered useful probiotics for protecting the liver from xenobiotics and hepatitis B virus, and as well as useful as a functional food for maintaining human health.

• School Mathematics
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• v.14 no.1
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• pp.85-107
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• 2012

Problem solving is important in school mathematics as the means and end of mathematics education. In elementary school, inductive reasoning is closely linked to problem solving. The purpose of this study was to examine ways of improving problem solving ability through analysis of inductive reasoning process. After the process of inductive reasoning in problem solving was analyzed, five different stages of inductive reasoning were selected. It's assumed that the flow of inductive reasoning would begin with stage 0 and then go on to the higher stages step by step, and diverse sorts of additional inductive reasoning flow were selected depending on what students would do in case of finding counter examples to a regulation found by them or to their inference. And then a case study was implemented after four elementary school students who were in their sixth grade were selected in order to check the appropriateness of the stages and flows of inductive reasoning selected in this study, and how to teach inductive reasoning and what to teach to improve problem solving ability in terms of questioning and advising, the creation of student-centered class culture and representation were discussed to map out lesson plans. The conclusion of the study and the implications of the conclusion were as follows: First, a change of teacher roles is required in problem-solving education. Teachers should provide students with a wide variety of problem-solving strategies, serve as facilitators of their thinking and give many chances for them ide splore the given problems on their own. And they should be careful entegieto take considerations on the level of each student's understanding, the changes of their thinking during problem-solving process and their response. Second, elementary schools also should provide more intensive education on justification, and one of the best teaching methods will be by taking generic examples. Third, a student-centered classroom should be created to further the class participation of students and encourage them to explore without any restrictions. Fourth, inductive reasoning should be viewed as a crucial means to boost mathematical creativity.