• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.1934-1939
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• 2006

Current digital communication system is selecting very various digital Modulation way. Need linear power amplifier necessarily to reduce interference for contiguity channel maximum in this communication system and at the same time, power amplifier of high efficiency is required. In this paper Compare with result of equilibrium power amplifier that design Doherty power amplifier of way that linearity and efficiency are improved at the same time through simulation optimization techniques and at the same time design through simulation, efficiency 20% linearity showed 10dB that is improved.

• Communications of Mathematical Education
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• v.24 no.4
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• pp.891-907
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• 2010

This study analyzed the Fundamental Theorem of Calculus from the historical, mathematical, and instructional perspectives. Based on the in-depth analysis, this study suggested an alternative way of teaching the Fundamental Theorem of Calculus.

• Journal of Korea Society of Digital Industry and Information Management
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• v.15 no.3
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• pp.119-128
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• 2019

Minecraft game is a sandboxed game based on a high degree of users' freedom; the game encourages its users to recreate various play patterns to increase their immersion. Although recently there were many studies that use Minecraft game techniques to improve the teaching methods but still not well adapted due to being applications-based techniques. In this paper, we present a teaching model that utilizes the same concept of the Minecraft games in where learners customize the class concepts based on their needs. Moreover, Minecraft-based learning games attempt to be used for learner-led, creativity and programming instruction, to overcome these use-cases limitations, by our study we aim to include the Minecraft-based learning games in class teaching activities, theoretical and practical lessons. In this way, we intend to increase interest in programming lessons, and to increase immersion as another way of game learning. In the future, we attempt to measure various effects of the uses of Minecraft-game-based teaching in programming classes compare to the traditionally used methods.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.68.2-68.2
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• 2019

Chemical abundance ratios of ultra metal-poor (UMP; [Fe/H] < -4.0) stars can provide important constraints on the early chemical enrichment of the Milky Way (MW), associated with the nucleosynthesis processes that occurred during the evolution of their progenitors, which are presumably the first generation of stars. Despite their importance, only about thirty UMP stars have been discovered thus far. In an effort to identify such stars additionally, we selected UMP candidates from low-resolution (R ~ 2000) spectra from the Sloan Digital Sky Survey and Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST), and obtained with Gemini/GRACES high-resolution (R ~ 40,000) spectra of 15 UMP candidates. In this study, we present the results of the chemical abundance analysis of the UMP candidates. Furthermore, we compare the abundance patterns of our UMP stars with those of various metal-poor stars from literature to understand the early chemical evolution of the MW.

• Journal of Public Diplomacy
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• v.2 no.1
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• pp.43-68
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• 2022

Multiple modes of communication on social media can contribute to public diplomacy in informing, conversing, and networking with members of foreign publics. However, manipulative behaviours on social media, prevalent especially in high tension contexts, create disruptions to authentic communication in what could be grey/black propaganda or information warfare. This study reviews existing literature about models of public diplomacy to guide an empirical study of China's communication in the #SouthChinaSea conversation on Twitter. It uses computational methods to identify, record, and analyze one-way, two-way, and network communication of China's actors. It employs manual qualitative research to determine the nature of China's actors. On that basis, it assesses China's Twitter communication in the issue against various models of public diplomacy.

• Journal of Korea Society of Industrial Information Systems
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• v.15 no.4
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• pp.1-5
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• 2010

To operate safely VANET applications, authenticaton is necessary to identify val d participants and prevent malicious parties from modifying messages. This paper proposes an efficient authentication protocol for the vehicle registration in VANET environment. The topology of VANET changes rapidly due to high-speed movement of vehicles, thus it is need to reduce the computational burden of the authentication protocol. Therefore, this protocol uses only one-way hash functions and EOR operations to register vehicles.

• Development and Reproduction
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• v.27 no.1
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• pp.1-7
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• 2023

Small-cell lung cancer (SCLC) continues to be the deadliest of all lung cancer types. Its high mortality is largely attributed to the unchangeable development of resistance to standard chemo/radiotherapies, which have remained invariable for the past 30 years, underlining the need for new therapeutic approaches. Recent studies of SCLC genome revealed a large number of somatic alterations and identified remarkable heterogeneity of the frequent mutations except for the loss of both RB and P53 tumor suppressor genes (TSGs). Identifying the somatic alterations scattered throughout the SCLC genome will help to define the underlying mechanism of the disease and pave the way for the discovery of therapeutic vulnerabilities associated with genomic alterations. The new technique made it possible to determine the underlying mechanism for the discovery of therapeutic targets. To these ends, the techniques have been focused on understanding the molecular determinants of SCLC.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.50.1-50.1
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• 2019

Ultra Metal-Poor (UMP; [Fe/H] < -4.0) stars are thought to be true second generation of stars. Thus, the chemistry and kinematics of these stars serve as powerful tools to understand the early evolution of the Milky Way (MW). However, only about 40 of these stars have been discovered thus far. To increase the number of these stars, we selected UMP candidates from low-resolution spectra (R ~ 2000) of the Sloan Digital Sky Survey (SDSS) and Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST), and performed high-resolution (R ~ 40,000) spectroscopic follow-ups with Gemini/GARACES. In this study, we present chemical and kinematic properties of the observed UMP candidates, and infer the nature of their progenitors to trace the chemical enrichment history of the MW.

• Journal of Families and Better Life
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• v.13 no.4
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• pp.85-100
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• 1995

The objectives of this study are : 1) To clarify the definition of conspicuous consumption. 2) To examine the degree of conspicuous consumption amongst urban housewives. In this research conspicuous consumption is defined as the use and acquisition of goods and services to ostentatiously display wealty with the purpose of establishing or sustaning a status through the symbolic values of goods and services, The data used in this study included 670 housewives living in Seoul. Statistics used for data analysis were frequencies means standard deviation and one-way anova. The research results can be summarized as follows. First the propensity for conspicuous consumption differs significantly according to wife's age wife's education and husband's job. Second the propensity for conspicuous consumption in high quality and high price preference is high, And the propensity for conspicuous consumption in house and furniture is high.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.437-440
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• 2009

High-frequency induction is an efficient way to heat mold surface by electromagnetic induction in a non-contact manner. Thanks to its capability of rapid heating and cooling of mold surface, it has been recently applied to the injection molding. The present study applies the high-frequency induction heating for elimination of weldlines in an injection-molded plastic part. To eliminate weldlines, the mold temperature of the corresponding weld locations should be maintained higher than the glass transition temperature of the resin material. Through experiments, the maximum temperature of $143^{\circ}C$ is obtained on the mold surface around the elliptic coil, while the temperature of the mold plate is lower than $60^{\circ}C$. An injection molding experiment is then performed with the aid of induction heating, and the effect of induction heating conditions on the surface appearance of the weldline is investigated.