• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.3
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• pp.228-238
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• 2002

This paper presents a digital controller of the electronic ballast using high frequency modulation method for the metal halide lamp. The proposed controller includes the control algorithm for soft starting, no load protection, over current protection and power control. The proposed digital controller, moreover, has the high frequency modulation scheme and the tracking algorithm to avoid acoustic resonance phenomena. For the math production with the low cost using the ASICs (Application Specific Integrated Circuit), the proposed digital controller has been designed with the FPGAs(Field Programmable Gate array) only, without any microprocessor. In this paper, the detail digital control algorithms are described and the experimental results of prototype 150w metal halide electronic ballast are presented.

• Journal of Preventive Medicine and Public Health
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• v.39 no.1
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• pp.67-73
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• 2006

Objective: This study was conducted to investigate the relationship between the intention of smoking and its related factors in high school students. Methods: Our study subjects were 1,203 high school students who resided in one city and in one county region. We conducted a self-administered questionnaire survey from June 7 to June 19, 2004. Both the decisional balance and temptation inventory showed high reliability estimates. We provided good fit for the 12-item decisional balance inventory and the 10-item temptation inventory by using a confirmatory factor analysis. We also used multiple logistic regression analysis to identify the major contributing factors for the intention to start smoking. Results: On the univariate analysis, the subjects who were female, the 2nd and 3rd grade students, the students in vocational high school, the ex-drinkers or current drinkers, and ex-smokers were found to be significantly more distributed in the groups with intention to start smoking. Except for the concept of the cons, the group with intention to start smoking showed significantly higher standardized T scores for the 7 concepts of decisional balance and temptations. On the multiple logistic regression analysis, the females, the 2nd and 3rd grade students, the students in vocational high school, the experience of cigarette smoking and low T score of the cons were significantly related to the intention to start smoking. Conclusions: The intention to start smoking in high school students was affected by various factors such as gender, the school grade and the experience of smoking. Therefore, further research should be conducted for providing the essential data for developing a brief instrument for selecting the groups with intention of starting smoking among adolescents.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.1
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• pp.43-48
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• 2019

The presence of shops necessary for everyday life is a factor that increases the satisfaction of residential environment. From the perspective of founders, establishing businesses with high needs of local residents is a factor that affects business success. In this paper, we try to find out the status of businesses closely related to everyday city life. And it analyzes whether the formation of these businesses is consistent with the initial consumer needs of the new city. The purpose of this paper is to derive meaningful results that both the business founder and consumer can win-win. The current status of the life-friendly businesses and the needs of citizens were analyzed in the S city. As a results of analysis, the needs for education appears strongly at the early stage of urban development. And it shows a characteristic of being weakened to some extent with the passage of time. On the other hand, the needs for food, which is the basic requirement of life, has a low starting and steadily increasing character.

• Progress in Superconductivity and Cryogenics
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• v.11 no.1
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• pp.1-4
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• 2009

Mechanical and electrical properties of silver stabilizer layer of coated conductor, which as prepared with nano silver paste as starting materials, have been investigated, Nano silver paste was coated on a YBCO film by dip coating process at a diping speed of 20m/min. Coated film was dried in air and heat treated at $400{\sim}700^{\circ}C$ in an oxygen atmosphere. Adhesion strength between YBCO and silver layer was measured by a tape est(ASTM D 3359). Hardness and electrical conductivity of the samples were measured by pencil hardness test (ASTM D 3363) and volume resistance test by LORESTA-GP (MITSHUBISHD, respectively. The sample heat-treated at $500^{\circ}C$ showed poor adhesion 1B, but samples heat treated at higher than $600^{\circ}C$ showed enhanced adhesion of 5B. The silver layer heat-treated at $700^{\circ}C$ showed the high hardness value larger than 9 H, low volume resistance, surface resistance value as well as superior current carrying capacity compared to sputtered silver. SEM observations showed that a dense silver layer was formed with a thickness of about $2{\mu}m$. Dip coated silver layer prepared by using nano silver paste showed superior electrical and mechanical characteristics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2722-2728
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• 2011

3Phase PWM rectifier has become increasingly popular due to its capability of nearly sinusoidal waveform of the input current, and nearly unity power factor operation as a AC/DC rectifier of high capacity telecommunication power supply system. Generally, PI controller is used as a voltage controller of PWM rectifier and voltage controller must be designed to have low overshoot in transient state to get a reliability and stable operation. However, in the application of telecommunication in which load condition is varied very fast, the voltage controller must have a large bandwidth to reduce output voltage variation. The PI controller with large bandwidth arouse the excessive overshoot of the output voltage, and this large output voltage variation degrades the reliability of communication power of the three-phase PWM Rectifier. In this paper, new IP voltage controller for 3 phase PWM rectifier is proposed which has relatively low transient output voltage variation. The improved output characteristics of the transient state voltage responses of the starting and at load changes of the proposed voltage controller are proved by simulations and experiments.

• Journal of the Korean earth science society
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• v.45 no.1
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• pp.19-36
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• 2024

The global seasonal forecasting system version 6 (GloSea6) operated by the Korea Meteorological Administration for 1- and 3-month prediction products does not include complex atmospheric chemistry-aerosol physical processes (UKCA). In this study, low-resolution GloSea6 and GloSea6 coupled with UKCA (GloSea6-UKCA) were installed in a CentOS-based Linux cluster system, and preliminary prediction results for the spring of 2000 were examined. Low-resolution versions of GloSea6 and GloSea6-UKCA are highly needed to examine the effects of atmospheric chemistry-aerosol owing to the huge computational demand of the current high resolution GloSea6. The spatial distributions of the surface temperature and daily precipitation for April 2000 (obtained from the two model runs for the next 75 days, starting from March 1, 2000, 00Z) were compared with the ERA5 reanalysis data. The GloSea6-UKCA results were more similar to the ERA5 reanalysis data than the GloSea6 results. The surface air temperature and daily precipitation prediction results of GloSea6-UKCA for spring, particularly over East Asia, were improved by the inclusion of UKCA. Furthermore, compared with GloSea6, GloSea6-UKCA simulated improved temporal variations in the temperature and precipitation intensity during the model integration period that were more similar to the reanalysis data. This indicates that the coupling of atmospheric chemistry-aerosol processes in GloSea6 is crucial for improving the spring predictions over East Asia.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.2
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• pp.151-157
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• 2003

Obtaining a sufficient amount of healthy keratinocytes from a small tissue is difficult. However, ORS cells can be a good source of epithelium since they are easily obtainable and patients do not have to suffer from scar formation at donor sites. Accordingly, the current study modified the conventional primary culture technique to overcome the low propagation and easy aging of epithelial cells during culturing. In a conventional primary culture, the average yield of human ORS tells is 2.↑ $\times$ 10$^3$cells/follicle based on direct incubation in a trypsin (0.1%)/EDTA(0.02%) solution for 15 min at 37$^{\circ}C$, however, our modified method was able to obtain about 6.9 $\times$ 10$^3$cel1s/follicle using a two-step enzyme digestion method involving dispase (1.2 U/mL) and a trypsin (0.1%)/EDTA (0.02%) solution. Thus, the yield of primary cultured ORS cells could be increasd three times higher. Furthermore, a total of 2.0 $\times$ 10$^{7}$ cells was obtained in a serum-free medium. while a modified E-medium with mitomycin C-treated feeder tells produced a total of 6.3 $\times$ 10$^{7}$ Cel1s over 17 days When Starting With 7.5 $\times$ 10$^4$cells. Finally, We Confirmed the effectiveness of our ORS tell isolation method by presenting their ability for reconstructing the bioartificial skin epithelium in vitro

• The Korean Journal of Air & Space Law and Policy
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• v.25 no.2
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• pp.201-230
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• 2010

With starting the industry of automobiles, railroads and mining, the legal principle of "erlaubtes Risiko" that began as a means of maintaining the revitalized world for the cause of social utility has interpreted as a system of negligence theory in the precedent while it has gained academic recognition. Yet in aircraft operation, which is one area of high technology, CAT which can be the cause of some accidents or events or thunderstorm with turbulence is an abnormal meteorological phenomenon with frequent change that cannot be monitored perfectly just as some patient with unstable condition and that cannot be ascertained about not only the possibility of its happening but also the degree of how big the accident is. Yet the use of jet current which has the possibility of CAT can be an act of high social utility where we not only drastically cut down on time fuel also guarantee the arrival and departure on schedule when landing in airports that have thunderstorm which does not appear as fatal risk. Although we could take some measures where we can predict and avoid the potential risk, easing the regular duty of care is necessary by applying the legal principles of permitted risk concerning the incidents and accidents caused by operating in areas with the risk of turbulence or CAT with the low probability by the reason of social utility.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.3
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• pp.63-74
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• 2014

From the 1950s, the science parks were begun the composition as a way for innovation and commercialization in the world around developed countries. Since the 1980s, Korea also starting with quantitative investment in R & D for technology innovation, so far has been a continuous effort. Korea's patent creation level according to these R & D investment is already within the world's top 10, but the fact that the domestic technology trade balance appearing current competitive level compared to the developed technology is very insufficient. This means that the creation of economic value is low as compared with financial commitment. Therefore the plans to ensure the economic value through technology are required. As one of plans to do this for local economy activation through technical advances, constructing regional innovation systems and making science parks have been made. These science parks are required to develop the basic original technology in order to secure new growth engines, but the science parks in Korea are facing difficulties of performing research and development for regional industry advancement and local economy activation. Accordingly, this study attempts to organize the concept of 'science park' is similar but there is difference, and to compare institutions with similar functions based on regional innovation systems theory. In addition, the study is to obtain the application plans of basic original technology in science & research Parks through the model for overcoming weaknesses of Korea's innovation system and enabling organic cross-linking between institutions.

• Korean Journal of Social Welfare Studies
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• v.49 no.2
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• pp.257-295
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• 2018

This study delineates how recipients access, understand, and make use of social welfare information in their life-worlds. Through this vivid illustration about recipients' information behaviors, this research aims to suggest that government-centred welfare informatization policy should be readjusted. South Korean government has made enormous efforts to deliver and share social welfare information and knowledge with recipients, by organizing IT eduction programmes, offering free computers, and opening welfare portals. However, despite of such endeavors, not a few recipients find difficulty in gaining, grasping, and using welfare information. In fact, welfare informatization programmes have so far been initiated by the governmental bureaucratic system, and the voice of recipients have hardly been reflected on the informatization policy. Starting from this problem, this study examines how low-income recipients perceive and accept social welfare information in their daily lives and reflects on social welfare information at their point. For this purpose, this research conducted in-depth interviews with 14 recipients and analyzed the data using a framework analysis method. Based on the results, it raises the need for the remodelling of current welfare informatization measures from the perspective of recipients rather than following the custom of the bureaucratic system.