• Journal of Power Electronics
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• v.18 no.1
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• pp.225-233
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• 2018

This paper proposes a universal system control strategy for voltage source converter (VSC) based high voltage direct current (HVDC) systems. The framework of the designed control strategy consists of five layer structures considering the topology and control characteristics of the VSC-HVDC system. The control commands sent from the topmost layer can be transmitted to the next layer based on the existing communication system. When the commands are sent to each substation, the following transmission of commands between the four lower layers are realized using the internal communication system while ignoring the communication delay. This hierarchical control strategy can be easily applied to any VSC-HVDC system with any topology. Furthermore, an integrated controller for each converter is designed and implemented considering all of the possible operating states. The modular-designed integrated controller makes it quite easy to extend its operating states if necessary, and it is available for any kind of VSC. A detailed model of a VSC-HVDC system containing a DC hub is built in the PSCAD/EMTDC environment. Simulation results based on three operating conditions (the start-up process, the voltage margin control method and the master-slave control method) demonstrate the flexibility and validity of the proposed control strategy.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.2
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• pp.47-54
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• 1996

UASB reactor was operated for treating wastewater containing high sulfate to assess their performance, competition between sulfate-reducing bacteria(SRB) and methane-producing bacteria(MPB), and the change in the characteristics of microbial granules according to change of hydraulic retention time(HRT) in the reactor. The reactor was fed with a synthetic moderate strength wastes(glucose, 2000 mgCOD/l) containing high sulfate($2400mgSO_4{^{2-}}/l$). The organic loading rate(OLR) ranged from 1.5 to 3.0 gCOD/l.d as HRT maintained 15 to 30 hrs in the stage I. The COD removal efficiency was between 80 to 92%. During this period, methane yield rapidly decreased from 0.3 to 0.1 1 $CH_4$/gCODremoved. While sulfide concentration in the effluent increased from 80 to 200 mgS/l. This indicates that SRB becomes dominant over MPB at a relatively long HRT in the excess sulfate. When OLR of reactor maintained from 5 to 8 gCOD/l.d in the stage II, methane yield increased from 0.1 to 0.17 1 $CH_4$/gCODremoved regardless of decrease of COD removal efficiency. This indicates that SRB is more sensitive to the change of a short HRT than MPB. In the competition between SRB and MPB, about 30% of the removed COD was utilized by SRB at HRT of 30 hrs during the start-up period, while about 73% was used by SRB at HRT of 15hrs at the final step of second experimental stage. Whereas after shock exposure of OLR about 62% was utilized by SRB at HRT of 5hrs. It indicates that SRB is strongly suppressed by the wash-out of significant dispersed SRB since a large electron flow is distributed to the MPB. In addition, the granulation in the presence of high sulfate is unfavoured at a long HRT because of substrate transport limitations into MPB like Methanothrix spp. which is an important factor in the composition of the granules. Accordingly, granule sizes in the UASB reactor decreased with time due to weak network frame of granules by the decreased activity of MPB.

• Psychiatry investigation
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• v.15 no.12
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• pp.1188-1202
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• 2018

Objective This study protocol aims to determine, using a rigorous approach in patients with bipolar disorder (BD) and non-seasonal major depressive episode (MDE), the characteristics of bright light therapy (BLT) administration (duration, escalation, morning and mid-day exposures) depending on the tolerance (hypomanic symptoms). Methods Patients with BD I or II and treated by a mood stabilizer are eligible. After 1 week of placebo, patients are randomized between either morning or mid-day exposure for 10 weeks of active BLT with glasses using a dose escalation at 7.5, 10, 15, 30 and 45 minutes/day. A further follow-up visit is planned 6 months after inclusion. Patients will be included by cohorts of 3, with at least 3 days of delay between them, and 1 week between cohorts. If none meet a dose limiting toxicity (DLT; i.e hypomanic symptoms), the initiation dose of the next cohort will be increased. If one patient meet a DLT, an additionnal cohort will start at the same dose. If 2 or 3 patients meet a DLT, from the same cohort or from two cohorts at the same dose initiation, the maximum tolerated dose is defined. This dose escalation will also take into account DLTs observed during the intra-subject escalation on previous cohorts, with a "Target Ceiling Dose" defined if 2 DLTs occured at a dose. Discussion Using an innovative and more ergonomic device in the form of glasses, this study aims to better codify the use of BLT in BD to ensure a good initiation and tolerance.

• Journal of the Korea Convergence Society
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• v.10 no.7
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• pp.199-211
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• 2019

This study analyzed the research trends of college students' entrepreneurship in 172 scholarly articles in the registered journals of the Korea Research Foundation from 2010 to 2018. The results of this study are as follows: First, the research areas and topics on university students' entrepreneurship focuses on not only characteristics of entrepreneurship and entrepreneur but also entrepreneurship education. Also, the research method was dependent on the quantitative research method coupled with the statistic techniques such as descriptive statistics, correlation, t-test, ANOVA, regression analysis, and structural equation modeling. In future research, it is necessary to expand research areas to startup idea design, startup business environment and policies. Also, it is necessary to explore various variables related to entrepreneurship, not focusing on specific variables such as entrepreneurship, entrepreneurship education as well as to analyze meta analysis of the relationship between the variables influencing on the entrepreneurial intention. In addition, qualitative research and mixed research are needed to explore the process of developing entrepreneurship and the factors affecting the process of entrepreneurship.

• Asia-Pacific Journal of Business
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• v.12 no.1
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• pp.151-163
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• 2021

Purpose - The break-even point refers to the point where total profit and total cost coincide, and from this point on, the entrepreneur's decision-making takes a different route. Strategic decisions can be made for more efficient operation and eventually for more likelihood for growth and sustainability if a startup figures out when it recoups the investment and switches to a net profit. Design/methodology/approach - 748 creativity and skill-based sole proprietors in manufacturing industry were examined to demonstrate the effect of the entrepreneur's entrepreneurial experience and education level, the business launch preparation time, or the self-financing on the achievement of break-even point. Findings - While the business launch preparation time lowered the likelihood of reaching a break-even point, self-financing increased the likelihood. As a result of further analysis by subdividing into subgroups according to skill level, only the business launch preparation time was statistically significant in the highly skilled industries. In the low skilled industries, in addition to the business launch preparation time, the CEO's education level and the self-financing were statistically significant. Research implications or Originality - The longer the business launch preparation time, the higher the start-up cost, which increases the burden of initial cost recovery, and the agile response to market changes is thereby delayed, resulting in the business idea losing its appeal. Self-financing not only provides stability and strong motivation for the business operation but also promotes careful spending which contributes to the achievement of break-even point. In particular, it is found that practical experience is more useful than theoretical knowledge in low skilled industries. Due to the limitation of secondary data based on the recollection, the time required to reach a break-even point, percentage of financing sources, etc. may include cognitive errors. In addition, variables are not included that explain the characteristics of creativity and skill-based sole proprietorship, so it is necessary to exercise caution with the actual application.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.823-831
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• 2021

In the Internet age, the digital cultural industry is booming, start-up companies want to win a place in the fiercely competitive red sea market of the Internet, innovative business models have become an important challenge and opportunity for countless companies. Taking the virtual idol "Hatsune Miku" as the example, the analysis is carried out at the levels of technological innovation, value proposition, resource combination, operation process and marketing model. By comparing the differences between the first-generation software Meiko of Crypton and the second-generation software "Hatsune Miku", we will study the components of the business model to explore the characteristics and advantages of this business model, and in-depth operation models and innovations. The analysis is expected to provide a substantial reference for other electronic product and software development companies in their business models.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.10
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• pp.251-259
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• 2018

This study is to understand the entrepreneurship of youth and entrepreneurship education of youth, to examine the characteristics of entrepreneurship education of youth between South Korea and United States. And entrepreneurship is also the process of creating a new organization, which is understood as a process by an individual and a group of entrepreneurs who possess qualities and abilities with social opportunities, and move them into action and practice. There is a need for a comprehensive entrepreneurial mentality training and execution center for youth. To discussion social changes between South Korea and United States. The United States uses Junior Achievement ASK model. In contrast, South Korea through systematic and proactive education development, but due to the lack of standard founding education content. Therefore, it presented the need for professional institutions for comprehensive entrepreneurship education and operation. Korea is not well organized with the lack of standard start-up education contents, so it is urgent to develop and distribute education actively. Although the United States has been leading education at the national level, foundations are conducting education more actively.

• Journal of the Korean Institute of Rural Architecture
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• v.25 no.3
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• pp.27-35
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• 2023

This study aims to provide implications for Korea's efficient application policies for closed schools by identifying the current status of how closed schools are revitalized in Japan and their supportive measures. In Japan, a total of 2,215 schools have closed from 1992 to 2001, and 8,580 schools from 2002 to 2020, with 10,709 closures occurring from 1992 to 2020. The average number is about 369 per year. In terms of the overall trend, the number of closed schools have been put into use and the numbers have increased from 70% in 2013 to 74% in 2020. To summarize the characteristics of the use, first, there is a complex phenomenon in which the use of closed schools are becoming more diverse. Second, closed schools are most often revitalized as educational facilities for residents, followed by social sports facilities, social education facilities and cultural facilities. Third, the use of closed schools in the industries are increasing as they are used as "corporal facilities and start-up support facilities". In order to promote the use of closed schools, the Ministry of Education, Culture, Sports, Science and Technology in Japan promoted the simplification and elasticity of property disposal procedures in 2008. Since 2010, the disclosure of information on closed facilities and matching service between providers and users have been unified through the "Let's Connect to the Future ~ Closed School for All" project. The Cabinet Office including the four offices, and five central governments are advocating the use of closed schools by promoting subsidy support projects.

• Journal of Practical Engineering Education
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• v.15 no.2
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• pp.285-297
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• 2023

This study was conducted to explore the career competencies among the middle-aged employment vulnerable groups and to provide the basis for systematic career development and human resource development for the middle-aged and employment vulnerable groups. Interviews and expert advice for the middle-aged (40-64 years old) employment vulnerable groups were conducted. The main research results as follows. First, middle-aged employment vulnerable groups have different career requirements depending on their characteristics. Second, the career competencies of the middle-aged employment vulnerable group were composed five factors and 21 sub-detailed competencies including career cognitive competencies, career skill competencies, career attitude competencies, career transition competencies, and career resource management competencies. Third, as a result of the priority analysis of Borich and Locus for Focus, career goal setting, career implementation competency, employment and start-up information, job search skills were the top priorities, career identity, digital literacy, job market knowledge, and infrastructure utilization were the second priority.

• Journal of Korean Society of Rural Planning
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• v.29 no.4
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• pp.137-152
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• 2023

Data is indispensable for digital transformation of agriculture with the development of innovative information and communication technology (ICT). In order to devise and prioritize strategies for enhancing data competitiveness in the agricultural sector, we employed an Analytic Hierarchy Process (AHP) analysis. Drawing from existing research on data competitiveness indicators, we developed a three-tier decision-making structure reflecting unique characteristics of the agricultural sector such as farmers'awareness of the data industry or awareness of agriculture among data workers. AHP survey was administered to experts from both agricultural and non-agricultural sectors with a high understanding of data. The overall composite importance, derived from the respondents, was rated in the following order: 'Employment Support', 'Data Standardization', 'R&D Support', 'Start-up Ecosystem Support', 'Relaxation of Regulations', 'Legislation', and 'Data Analytics and Utilization Technology'. In the case of experts in the agricultural sector, 'Employment Support' was ranked as the top priorities, and 'Legislation', 'Undergrad and Grad Education', and 'In-house Training' were also regarded as highly important. On the other hand, experts in the non-agricultural sector perceived 'Data Standardization' and 'Relaxation of Regulations' as the top two priorities, and 'Data Center' and 'Open Public Data' were also highly rated.