• Journal of Educational Research in Mathematics
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• v.16 no.4
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• pp.273-295
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• 2006

It is the purpose of this study to help computational estimation study to settle down in effective teaching method through analysis how students are understanding computational estimation and what occurs using computational estimation in actual life problem situations. I set 3 cases to accomplish these purposes. (1) How students are understanding computational estimation? (2) How students' computational estimation ability is in applying actual life problem situation? (3) What is students' different attitudes in an actual life problem situation before studying computational estimation and after? To accomplish tile purpose, I chose 6 third grade students and taught 'Computational estimation using actual life problem situation' and analyzed students computational estimation processing. Then I arranged the computational estimation processing in an actual life problem situation and differences between the before and tile after. As a result, I obtained the followings. (1) Need of estimation: Every students could recognize the need of estimation with experiencing an actual life problem situation. (2) Choosing the order of decimals: Students could choose appropriate order of decimals according to an actual life problem situations. (3) Using strategy: They usually use rounding strategy and quite often use special number and compatible number strategy.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.5
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• pp.298-311
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• 2003

Iterative Fourier transform algorithm, (IFTA) is tile iterative numerical algorithm for the design of the diffractive optical elements (DOE), by which the phase distribution of a DOE converges on a local optimal solution. The convergence of IFTA depends on several factors 3s initial phase distribution, the structure of the degree of freedom on the observation plane, and the values of internal parameters. In this paper, we analyze tile dependence of the convergence of IFTA on an internal parameter of IFTA, the relaxation parameter, and propose a new hybrid scheme of genetic algorithm and IFTA to obtain more accurate solution.

• Journal of Ginseng Research
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• v.29 no.3
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• pp.152-158
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• 2005

For several thousand years, Korea ginseng has been used as medicinal herb in the oriental countries. Korea is the ginseng suzerain and, for that reason, tile ginseng as a special crop In Korea has been exported to the World market since the era of the three Kingdoms. However, recently, the intermational market share of Korea ginseng products has been significantly reduced due to the mass production of ginseng from China and Canada. Besides, America with aggressive marketing strategy take the leadership in the international ginseng market. Therefore, it is necessary for Korea to know and understand world ginseng market mood and situation. The object of this study is to identify the actual consumption conditions and consumer perception of ginseng at the major consumptive countries in tile world. The findings of this study mean that the consumer behavior and perception of ginseng is difficult depending on country. At the result, it is expected that this study will be used to apply ginseng in various fields.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.124-130
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• 2021

Dental prosthesis translucency importantly contributes to aesthetic outcomes. The purpose of this study was to investigate the effect of drying time and zirconia coloring agent type on translucency. For the experiment, 90 circular specimens were fabricated for each zirconia block. Then, zirconia specimens were treated with a coloring agent for 180 seconds and dried for 0 seconds (undried), 30 seconds (intermediate dry), or 30 minutes (complete dry). Then, a specimen was placed on a black standard tile or a white standard tile, and using a standard D65 light source reflected was measured using the light removal method. A total of three repeated measurements were obtained per specimen. One-way ANOVA was used to compare and analyze the relationship between zirconia translucency and drying time. Zirconia and coloring liquid types were significantly associated with translucency (P < 0.001). Although no significant difference was observed with respect to drying time (P > 0.922), zirconia in the completely dried (30 minutes) state was more translucent.

• Lingua Humanitatis
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• v.2 no.1
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• pp.131-151
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• 2002

Park Dujin has written the nature poems through his keen sense for light and the emotion of Sinmyeong(the excited and enthusiastic mind) from his early poetry to his later poetry. His poetic emotions, with the periods of his composition of poems, are expressed in the juxtaposition of the waiting for something or the existential agony with the devout faith. But he has pursued tile monistic nature through the emotion of light and Sinmeoung. Therefore all his poems are characterized as the nature poems which expose the artistic wholeness transcending the ideology and spirit of his times. Up to the present, Korean ecological poems have been absorbed in examining and criticizing the crisis for the environmental pollution and the destruction of ecosystem. Therefore Korean ecological poems could not get out of the dualistic ecological consciousness of the opposing environment confronting between man and nature. The ecological peculiarity in Park Dujin's nature poems is not the level of the man-oriented environment or bioecology but the monistic nature which man and nature are unified. This fact can be said to be caused by the approach to the objects on the basis of the sense for light and the emotion of Sinmyeong which perceive the transcendental nature.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.425.2-425.2
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• 2016

토카막(TOKAMAK) 장치의 진공용기 및 용기내벽은 플라즈마(Plasma)에 의한 고열과 높은 에너지의 이온 입자들에 항상 노출되어 있는 환경이다. 토카막의 일종인 KSTAR장치의 진공용기는 스테인레스강(STS316)계열의 재질로 이루어져 있고, 플라즈마와 면하는 용기 벽면은 플라즈마에 대해 견딜 수 있도록 그라파이트 타일(graphite tile)로 구성되어 있다. 고에너지의 이온 입자들과 열플럭스(Heatflux)는 용기벽면과 용기를 침식시키고, 또한 이렇게 생겨난 분진(dust)들은 진공용기 내 여기저기를 떠다니게 되고, 플라즈마에 대해서 불순물로서 작용하게 된다. 본 연구에서는 감마분석법으로 플라즈마에 의해 진공용기 내에 집적된 분진들의 구성 성분을 분석하여 주요 출처를 규명할 수 있는 방법을 제시하고, KSTAR 플라즈마의 불순물 제어에 유용하게 활용 할 수 있는 데이터를 제공하여 향후 KSTAR의 고성능 플라즈마 기술개발에 일조할 수 있도록 하고자 한다.

• Transactions of Materials Processing
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• v.11 no.2
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• pp.147-154
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• 2002

The tension levelling Process is Performed to elongate the strip plastically In combination of tensile and bending strain so that all longitudinal fibers In the strip have an approximately equal amount ofn length and undesirable strip shapes are corrected to the flat shape. Thus paper is concerned with a simulation of the tension levelling process based on the analysis of tile unit model for the tension leveller. Analysis technique such as the sequential analysis of the unit model is suggested and verified with the assembly analysis of the unit model for the effective arts economic analysis of the full set of the tension leveller. Analysis of the full tension levelling Process using sequential unit models Is carried out for steel strips with the shape defect and provides the effect of the intermesh and optimum amount of the intermesh in tension levelling process.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2058-2061
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• 1997

A main research topic in PWM inverter drive system is to reduce the generated acoustic noise. One method to reduce the acoustic noise is to cause the switching pattern to be random. This RPWM(Random Pulse Width Modulation) technique for voltage controlled inverters is a kind of good solutions for reduction of acoustic noise and suppression of vibration. This paper describes a carrier frequency modulated real-time RPWM inverter. Changing the carrier frequency randomly, the power spectrum of tile acoustic noise was spread over the wide-band area. And experimental results showed that emitted noise is much more comportable and less annoying

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1933-1935
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• 1997

The availability of high power IGBT has led to development of controllable reactive power and harmonics compensation source for use in power transmission system. The paper describes the fundmental operating principles and several application examples. The control technique of reactive power and harmonics compensation for Distribution STATCON is presented, and the computer simulation results are shown to show the effectiveness of tile proposed control technique.

• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.3
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• pp.79-89
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• 2010

Cellular and Smart phone through the business and real life is associated with an increasing number of information processing, Breaches associated with mobile terminal Tile has occurred and cause Crime and damage. In this paper, Cellular and Smart phone for mobile forensics SYN scheme and JTAG scheme to target Cellular and Smart phone for the extraction of forensic data will be studied. SYN, JTAG approach to forensic analysis indicate with the process, Every Smart phone's OS specific performance and data extraction were compared. In the laboratory, Cell and smart phone with the SYN scheme and JTAG scheme to extract forensic data Improvement compared to the extraction is presented.