• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1082-1084
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• 2001

This paper presents a design techniques for an electronic ballast of HID lamps. An electronic ballast for HID lamps usually employs a high frequency resonant inverter and voltage-to-frequency converter to control the output and a half-bridge and series resonant circuit are chosen for the ballast. In this paper, the new lighting method for the stable ignition regardless of lamp types is designed. And this type of ballast has some useful functions such as surge protection, thermal protection, and dimmable function. Moreover the powerline communication skill is also used to transmit a dimming control signal.

• Elastomers and Composites
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• v.53 no.2
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• pp.48-51
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• 2018

10, 20, 30, and 40% of polyvinyl chloride (PVC) were added to nitrile butadiene rubber (NBR) to modify the latter. The NBR/PVC composites containing pure NBR were synthesized to investigate properties, such as crosslinking density, hardness, tensile strength, abrasion resistance, heat resistance, solvent resistance, and filler dispersion. The experimental result revealed a decrease in crosslinking density and heat resistance with increase in the PVC content. In contrast, addition of PVC to NBR resulted in enhancement of hardness, tensile strength, solvent resistance, and filler dispersion.

• Journal of Surface Science and Engineering
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• v.47 no.6
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• pp.282-286
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• 2014

Wear characteristic of the nitrided SKD61 which is a typical mold material using for the extrusion of Al6061 alloy was investigated. The surface of SKD61 was nitrided by salt bath and plasma processes. The thickness of surface nitride layer was about $8.9{\mu}m{\sim}21.3{\mu}m$. Reciprocating friction wear test conducted using pin on disk type indicated the plasma treatment followed salt bath has a lower friction coefficient and a smaller adhesive wear with Al6061 alloy. That was identified by the $Fe_4N$ which has a better wear resistance than FeN mainly formed by plasma nitriding.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.330-333
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• 2009

WSNs is evolving different kinds of networks depending on different circumstances, among those we have HWSNs (Hybrid Wireless Sensor Networks) which invokes sensor nodes mobility. In hybrid wireless sensor networks (HWSNs), reducing energy consumption of resource constrained and adaptability to the sensors nodes motion are the crucial problems; to overcome this we need a scalable MAC protocol. Many MAC protocols have been proposed by different researchers, but in this paper we propose LMAC because it outperforms S-MAC, T-MAC and D-MAC protocols comparing to its improvement of energy efficiency and mobile adaptability.

• Educational Technology International
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• v.24 no.1
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• pp.81-114
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• 2023

The study aimed to qualitatively examine middle school students' engagement in distance instruction during the COVID-19 pandemic. The participants comprised 119 students from a girls' middle school in Seoul, South Korea. To gain an in-depth understanding of the students' experiences, we collected their reflective journals, which included structured items about their learning engagement at three timepoints in 2020: April, July, and December. The following are the results: 10 themes and 18 concepts were derived, and they were integrated into causal conditions (sudden transition due to COVID-19), contextual condition (technology readiness, school education context), central phenomena (high level of behavioral engagement, low emotional engagement), interventional conditions (recognizing the potential of online learning, situational awareness about COVID-19 and online learning), action/interaction phenomena (development and use of self-regulated learning strategies), and consequences (changes in practices and perception towards online learning). Based on the findings, engagement patterns of the participants were classified into five types: proactive, conservative, receptive, reactive, passive learners. The present study demonstrated important findings that are essential for the improvement and development of engaging online learning strategies in the future.

• Educational Technology International
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• v.7 no.1
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• pp.99-110
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• 2006

Rapid innovation in ICT is transforming the way we work, the way we interact, the way we learn, and the way we live. In the education and training sector, ICT increases access to learning by making it possible for workers to fit their education into family and work schedules and by providing a greater programmatic choice of quality courses. ICT allows multiple workers to simultaneously enrol in training programs and work in their workplace in order to achieve their particular learning goals in a timelier manner. This paper deals with the ICT conditions, role of ICT, application of ICT, and effectiveness of ICT in the area of workforce development.

• Korean Journal of Human Ecology
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• v.16 no.6
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• pp.1269-1278
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• 2007

The purpose of this study was to investigate the relationship between the awareness of gender equality and practice of housing education contents in Technology Home Economics Subject of university students. Subjects were 488 university students located in JunBuk province. In this statistical analysis, SPSS 11.5 for Windows program was utilized to analyze frequency, t-test, one-way Anova, Duncan test, Ward's method, Pearson's correlation coefficient. The results of this study were follow: First, the university student's gender equality appeared a little above the middle level. Female student's gender equality was higher than male. Second, the university students' practice of housing education contents appeared at the middle level. Male students appeared to be higher than female at 'support and repair of housing' unit. Third, the higher university students have awareness of gender equality, the better they practice of housing education contents. Group one recording where the gender equality is high 'Living quarter application', 'Indoor environment and equipments' units the practice of housing education contents was high. Forth, correlation of variables differed significantly between university students' practice of housing education contents and the awareness of gender equality. As a conclusion, university students' awareness of gender equality play an important role in practice of housing education contents in their real life. These results should be provide fundamental information for improving of housing education contents in Technology Home Economics Subject.

• Journal of The Korean Association of Information Education
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• v.21 no.3
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• pp.285-296
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• 2017

In this study, we conduct SW education using robot in elementary school, to examine the effects of SW education using robot on CT and gender differences. In order to achieve the purpose of this study, SW education using robot was conducted to 143 students in 5, 6 grade in GyeongGi. After collecting data, we examined mean difference using matched pair t-test and ANCOVA. The results of this study were as follows: The SW education using robot is associated with significant improvements in CT, however, computational concepts is not associated with significant improvement in high initial score sub sample. And CT is not associated with gender. This study was investigated effects of the SW education using robot and identify gender differences. And expanded the understanding of the SW education using robot.

• Journal of Engineering Education Research
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• v.10 no.1
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• pp.5-19
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• 2007

A general education course is different from a major course in an engineering college. Therefore, they influence a learning outcomes according to their forms and contents. In particular, an engineering college in korea is open to argument against a general education course. Because a general education course has to observe the criterion of ABEEK. Consequently, the purpose of this study is to compare general education courses of engineering colleges in USA. For it, this study analyzes the completion method and academic area of a general education course. In result, this study suggests the property and implication of a general education course in an engineering college.

• Journal of The Korean Association of Information Education
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• v.16 no.1
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• pp.41-49
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• 2012

It is required that university students acquire information technology in order to adapt to the information society. Therefore, it is inevitable for universities to provide students with an effective curriculum to improve IT fluency. The purpose of this study is to analyze the content of the informatics learning programs in universities in Korea in terms of IT fluency which is defined by National Academy of Science NRC99. Based on the information that the Academy Information Center announced, the content analysis was carried out from September 2010 to June 2011. According to the result of the analysis, 84 of 201 universities provide the informatics education as a mandatory course. 29 of them mainly provide the programs about word processors, spreadsheet, and presentation that are regarded as contemporary skills. These programs cover the fundamental concept, but the contents which require intellectual capabilities are rarely addressed. Moreover, the informatics education has mainly focused on elementary and secondary education. In this sense, it is valid to analyze the contents and current states of the informatics learning programs required in higher education.