• Journal of Science Education
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• v.41 no.2
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• pp.267-280
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• 2017

The purpose of this study is to review the foundation of the representative early scientific societies and their major activities. The documents, books, and literature related to this study were collected through internet websites (e.g., google scholar, wikipedia) and analyzed by the qualitative content analysis method. The result of this study shows that requirement for the necessary resources to acquire or to prepare the instruments for the experiment is significantly increased with the rising importance of the experiments to conduct the scientific methods. As a consequence, scientists faced urgent necessities to conduct scientific experiments with cooperation and exchange of the newest information by establishing a community beyond the independent and individual research activity. Establishment of the scientific societies is the result of these necessities. At the beginning of the scientific societies, the resources are provided by either wealthy patron or member contribution or public through foundation of government organization. This study provides the implications for future scientific societies.

• Journal of Science Education
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• v.41 no.1
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• pp.98-110
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• 2017

The purpose of this study is to compare the friendship expectation that gifted students perceived in the gifted class and the regular class. To this study, friendship expectation survey, which sub-domains were intimacy, ability similarity, and morality, was conducted to 121 gifted students. The results of this study were as follows: First, according to the results of comparing the friendship expectations of gifted students in the gifted class and the regular class, there were statistically significant differences in the sub-domains of intimacy and morality. But there was no significant difference in the sub-domain of ability similarity. Second, there were statistically significant differences in the some detail items of all sub-domain(intimacy, ability similarity, and morality). Based the results of this, the implications to understand the friendship of the gifted students were suggested.

• Journal of Science Education
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• v.42 no.2
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• pp.230-241
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• 2018

This study was conducted to see how science classes using astronomical observations software could affect elementary students' scientific learning motivations and academic achievements. For this, 24 sixth graders of G Elementary School were designated as experimental groups to provide classes in which astronomical observation software was used. The experimental treatment period was 4 weeks and the results were as follows. First, elementary science classes that used astronomical observation software were effective in boosting scientific learning motivation. Second, elementary science classes that used astronomical observation software were effective in enhancing academic achievements. From these study results, we could confirm that elementary science classes that used astronomical observation software were effective for elementary school students' motivation and academic achievements.

• Journal of Science Education
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• v.42 no.2
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• pp.120-131
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• 2018

The purpose of this study is to examine the characteristics of science gifted students' understanding of friction acting on a rolling object, and to examine the implications of teaching methods that can be derived from them. For this purpose, 48 students in grade 3 students who take advanced physics classes at the science high school for the gifted were asked to answer three questions about the friction problems. As a result, students' responses were divided into three types: rule, none-rule, and calculation. In addition, students of the rule type have difficulty in reasoning about the friction by using friction rules. We believe that students will be able to reach a deeper understanding of friction if we teach them to correctly infer the direction of friction without using friction rules, along with a strategy to emphasize relative motion in contact.

• Journal of Semiconductor Engineering
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• v.1 no.1
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• pp.1-12
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• 2020

Handling precise timing in high-speed transceivers has always been a primary design target to achieve better performance. Many different approaches have been tried, and one of those is utilizing the beneficial nature of injection locking. Though the phenomenon was not intended for building integrated circuits at first, its coupling effect between neighboring oscillators has been utilized deliberately. Consequently, the dynamics of the injection-locked oscillator (ILO) have been explored, starting from R. Adler. As many aspects of the ILO were revealed, further studies followed to utilize the technique in practice, suggesting alternatives to the conventional frequency syntheses, which tend to be complicated and expensive. In this review, the historical analysis techniques from R. Adler are studied for better comprehension with proper notation of the variables, resulting in numerical results. In addition, how the timing jitter or phase noise in the ILO is attenuated from noise sources is presented in contrast to the clock generators based on the phase-locked loop (PLL). Although the ILO is very promising with higher cost effectiveness and better noise immunity than other schemes, unless correctly controlled or tuned, the promises above might not be realized. In order to present the favorable conditions, several strategies have been explored in diverse applications like frequency multiplication, data recovery, frequency division, clock distribution, etc. This paper reviews those research results for clock multiplication and data recovery in detail with their advantages and disadvantages they are referring to. Through this review, the readers will hopefully grasp the overall insight of the ILO, as well as its practical issues, in order to incorporate it on silicon successfully.

• Journal of Semiconductor Engineering
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• v.1 no.1
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• pp.13-30
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• 2020

Radio frequency (RF) energy harvesting technology have become a reliable and promising alternative to extend the lifetime of power-constrained wireless networks by eliminating the need for batteries. This emerging technology enables the low-power wireless devices to be self-sustaining and eco-friendly by scavenging RF energy from ambient environment or dedicated energy sources. These attributes make RF energy harvesting technology feasible and attractive to an extended range of applications. However, despite being the most reliable energy harvesting technology, there are several challenges (especially power conversion efficiency, output DC voltage and sensitivity) poised for the implementation of RF energy harvesting systems. In this article, a detailed literature on RF energy harvesting technology has been surveyed to provide guidance for RF energy harvesters design. Since signal strength of the received RF power is limited and weak, high efficiency state-of-the-art RF energy harvesters are required to design for providing sufficient DC supply voltage to wireless networks. Therefore, various designs and their trade-offs with comprehensive analysis for RF energy harvesters have been discussed. This paper can serve as a good reference for the researchers to catch new research topics in the field of RF energy harvesting.

• Journal of Science Education
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• v.43 no.3
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• pp.271-283
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• 2019

This study examines the effects of virtual reality learning materials on the learners' learning motivation. For this study, we developed a virtual reality learning material for geological learning that allows observation of the characteristics of rocks in Korean topography that is closely related to learning contents. A 15-hour class was conducted with 91 students using virtual reality learning materials developed for first-year science high school students in D city. ARCS learning motivation strategy was used. Pre-test was conducted before the start of the classes and post-test was conducted after the classes. Statistical processing was analyzed using R-3.5.1 version program. As a result, the utilization of virtual reality learning materials has significant effects on attention concentration, satisfaction, and confidence in the learner's motivation factors. Using virtual reality in geological classes, students' interest in learning activities improve their immersion and concentration, which helps them understand the learning contents better.

• Journal of Science Education
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• v.43 no.3
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• pp.318-328
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• 2019

The purpose of this study is to investigate the teacher-students interactions shown in the images of elementary science class by preservice teachers. We applied nine analysis criteria in three domains such as emotional support (climate, regard for student perspectives, teacher sensitivity), classroom organization (instructional learning formats, behavior management, productivity), and instructional support (quality of feedback, language modeling, concept development) in the aspects of positive or negative interactions The results show that majority of student-teachers tended to prefer positive interactions especially regarding instructional learning formats or concept development. For the image of avoided class, they tended to show negative interactions related to instructional learning formats or regard for student perspectives. However, they showed extremely lower frequencies for some categories of negative interactions. Female preservice teachers tended to have slightly higher frequencies for some positive interactions than their counterpart. The findings indicate possible approaches to teachers' professional development and further research.

• Journal of Science Education
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• v.43 no.3
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• pp.342-362
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• 2019

This study is to explore the applicability of PBL classes in undergraduate education at a School of Dentistry. To do this study, PBL modules were developed and applied to the students with different background knowledge to easily learn Integrated Medicine and Lifescience classes. Participants were 12 students in the first year of Integrated MS program at P University. Four tutors who majored in Dentistry and had PBL teaching experience participated. As a result of the PBL classes, students' concepts and knowledge about gene expression and expression were expanded, and they recognized the importance of self-directed learners and experienced the importance of collaborative learning. PBL tutor presented a positive assessment of attending PBL class experience and the educational need for PBL instruction. The results of this study show the possibility of PBL as a model for Integrated Medicine and Lifescience class in Dentistry education.

• Journal of Science Education
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• v.43 no.3
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• pp.284-299
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• 2019

The purpose of this study is to investigate elementary school students' conceptions about the energy represented in the integrated theme 'Energy and life' of the 2015 revised science curriculum. The instruments were developed to grasp students' understanding about 'the concepts of energy,' 'forms of energy,' 'conversion of energy,' and 'energy use of plants and animals.' The surveys were conducted on 92 elementary school students in Seoul. The students' answers were analyzed by descriptive statistics, clouds and semantic network analysis. The results are as follows: 'Electricity' and 'electric energy' were most frequently mentioned as the associated concepts to energy and forms of energy, respectively. Also, the daily use of energy was mixed to the use in science. According to conceptual hierarchy, understanding of energy conversion was dependent on the understanding of energy forms. Although students have basic concepts about the energy use of plants and animals, they had some misconceptions and lack of understanding. The educational implications were discussed to teach 'Energy and Life' as integrated theme in new elementary school curriculum.