• Journal of Educational Research in Mathematics
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• v.27 no.3
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• pp.375-389
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• 2017

The purpose of this study is to analyze the difference and inter-connectivity between the definition of continuity in school mathematics and the definition of academic mathematics in four perspectives. These difference and inter-connectivity have not analyzed in previous papers. According to this study, the definition of 'continuity and discontinuity at one point' in school mathematics depends on the limit processing but in academic mathematics it depends on the topology of the domain. The target function of the continuous function in school mathematics is a function whose domain is limited to an interval or a union of intervals, but the target function of the continuous function in academic mathematics is all functions. Based on these results, the following two opinions are given in relation to the concept of continuity in school mathematics. First, since the notion of local continuity in school mathematics is based on limit processing, the contents of 2009-revised textbooks that deal with discontinuity at special point not belonging to the domain is appropriate. Here the discontinuity appears as types of infinite discontinuity, removable discontinuity, and step discontinuity. Second, the definition of a general continuous function is proposed to "if there is no discontinuity point in the domain of a function y = f(x), we call the function f a continuous function." This definition allows the discontinuity at special point in non-domain, but is consistent with the definition in academic mathematics.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.1
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• pp.60-68
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• 2016

This paper presents a 6~18 GHz 7-bit digital-controlled attenuator. The proposed attenuator is based on switched-T architecture, but no inductor is used for minimum chip size. The designed attenuator was fabricated using $0.18{\mu}m$ CMOS process, and characterized using on-wafer testing setup. The resolution(minimum attenuation step) and the maximum attenuation range of the attenuator were measured to be 0.22 dB and 28 dB, respectively. The measured RMS attenuation error and the RMS phase error for 6~18 GHz were less than 0.26 dB and $3.2^{\circ}$, respectively. The reference state insertion loss was less than 12.4 dB at 6~18 GHz. The measured input and output return losses were better than 9.4 dB over all frequencies and attenuation states. The chip size is $0.11mm^2$ excluding pads.

• Journal of Korean Philosophical Society
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• v.148
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• pp.183-211
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• 2018

Hyesim(慧諶) was an important figure that established a firm position of Suseonsa(修禪社), which was Jinul's Gyeolsadojang(結社道場), under the sponsorship of Choi Yi(崔怡)'s military regime. This paper reviews the background of "Ganbyeongron(揀病論)", in which Hyesim's Zen ideology is condensed, and its core content Sibjongbyeong(10 kinds of disease). With this, we can newly recognize following 5 facts: First, Sibjongbyeong occupied the most important position in Hyesim. It can be confirmed by the fact that Sibjongbyeong commonly occurred in the procedure that Hyesim was trusted by Jinul, in the "Ganhwagyeoleuiron(看話決疑論)" a Jinul's posthumous work published by Hyesim, and in "Ganbyeongron". Second, the publication of "Ganbyeongron" was not only for the systematic development of Ganhwa Gyeongjeol(看話 徑截) which Jinul had suggested but also for the consolidation of Hyesim's position in Suseonsa. Third, Hyesim wanted to establish the Ganhwa Gyeongjeol which Jinul had proposed through "Ganbyeongron". Fourth, the result of "Ganbyeongron" was to generalize the enlightenment suggested by Jonggo and Jinul in the practical aspect. Fifth, the generalization of enlightenment was not independent from the demands of the time that Choi Yi's military regime had asked. With this research approach, we can establish a clearer understanding about the "Ganbyeongron", Sibjongbyeong, and the Zen Buddhist aspects of early Suseonsa Era.

• Journal for History of Mathematics
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• v.26 no.2_3
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• pp.131-148
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• 2013

Euler's formula provides the topological characteristics of geometrical objects including polyhedra, and so an important mathematical concept. Descriptions on Euler's formula had been in the textbooks according to the 3rd through 7th National Mathematics Curriculum. However, they are gone after that. In this study, we focus on Euler characteristic and Euler's formula as an educational material for educations for the gifted or after-school educations. We first look at the mathematical history and the applications of Euler's formula and national curriculums to search for its mathematical and educational meaning. We further make a suggestion for a learning environment which provides a better education relying on search activities, not just depending on memorization, illuminated from the education of Euler's formula.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.222-229
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• 2016

Active synthetic aperture sonar on the small UUV is generated several trajectory disturbances under the influences of underwater environments, and causing a large error in the synthetic aperture processing. In this paper, we analyzed the effects of azimuth resolution for the phase mismatch of the synthetic aperture focus processing when the periodic or random trajectory disturbances was generated on the side direction. The simulation results show that ghost targets are generated and azimuth resolution is very deteriorated when disturbance amplitude is greater than $0.3{\lambda}$ and disturbance period is greater than $2L_{sa}$ in the periodic trajectory disturbances environments. And detection performance on the seabed small objects by the synthetic aperture processing is shown that there is a significant effects on the azimuth resolution depending on the types and conditions of the platform trajectory disturbance variations.

• Archives of design research
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• v.20
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• pp.87-96
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• 1997

Design education has been developed on the basis of higher education and continuing education for professional designers. This professional education has been regarded as a top priority in order to establish the discipline of design and status of designers in the society for the birth of design as a new discipline. Education of designers, however, should not be limited within the professional education led by higher education system. In order to educate designers having the competitiveness for the 21st century, it is necessary to expand the range of design education from higher education to general education by developing new programs. This paper is designed to investigate the importance and characteristics of 'Design-Based Education' by emphasizing design educational methods which are applied to the general education. As case studies, the current educational situations of England and United States of America are analyzed on the basis of their efforts and children's education programs. This study will provide the fundamental guideline for the development of K-12 design education in Korea.

• The Journal of the Korea Contents Association
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• v.16 no.6
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• pp.695-705
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• 2016

Recently, the status of public education has fallen and instead, the fever of private education has caused various social problem. Because of this private education, the polarization of education has become more serious. Under this circumstances, this study has focused on the effect of NIE (Newspaper in Education) which is expected to bring about some positive educational results. In foreign countries such as North America and European countries, NIE has already been introduced to schools. The educational effects of NIE has also been recognized. Korea also accepted NIE and expect positive educational effects. Therefore, the experimental study has been performed to prove the educational effect of NIE. Both for the middle school students and high school students, experimental group and control group were divided. After that, with the same study plan, experimental group studied with NIE method and control group studied with regular method. The results revealed that NIE method was effective to raise test scores. However, the subject interest and study attitude were not found to be related with the study methods. Implications were discussed.

• The Journal of Korean Association of Computer Education
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• v.19 no.5
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• pp.27-40
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• 2016

Changes in education or curriculum are based on the needs of the times and needs to address changes in knowledge. The purpose of this study was to provide implications regarding the general guidelines of the national curriculum by analyzing changes made in the high school informatics curriculum in which both needs are inherent. The study involved an analysis of the general guidelines to the national curriculum that involved the revision years 2007 and 2009, the composition of the 2015 revised curriculum, change in the status of the informatics curriculum, and the size of the informatics subject. As a result of the analysis it was found that several improvements are necessary, namely (1) the units need to be better clarified, (2) career electives need to be more appropriately composed, and (3) definitions of terms need to be better clarified. The significance of this study lies in the fact that it considered the viewpoint of software education emphasized in various countries around the world, and the general guidelines to the national curriculum were examined to learn what kind of organization and operation should be proposed for high school informatics.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2008.11a
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• pp.37-51
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• 2008

인삼은 재배적지에 대한 선택성이 매우 강한 식물이며, 기후 토양 등의 자연환경이 적당하지 않으면 인삼의 생육이 곤란하고, 생육이 가능하더라도 생산된 인삼의 형태, 품질 및 약효에서 현저한 차이를 나타내고 있다. 이러한 인삼의 식물학적 특성이 우리나라에서는 최적의 환경조건으로 인정되어 고려인삼은 세계적으로 최고의 품질로 높이 평가되는 이유이다. 하지만 실질적인 인삼의 생리활성물질에 대한 연구는 서구열강 및 일본에 의해 대다수 연구, 발표되었으며 또한 인삼의 우수성을 인정하여 넓은 영토와 수많은 과학적 지식으로 고려인삼의 우수한 품질을 앞서가려 하고 있는 것이 현실정이다. 특히 중국의 넓은 인삼재배면적에서 값싸게 생산된 인삼이 한국시장을 위협하고 있으며, 미국과 캐나다에서 수많은 연구비를 투자하여 자국삼인 화기삼의 홍보를 대대적으로 함으로서 전세계의 인삼시장의 변화를 유도하고 있고, 호주, 뉴질랜드에서도 청정인삼을 내세워 한국 및 전세계 인삼시장을 잠식해가고 있다. 이런 변화에 의하여 한때 인삼의 종주국으로 전세계의 인삼시장을 석권했던 한국의 고려인삼이 과거의 위상을 점차 잃어 가고 있는 실정이다. 따라서 인삼재배면적이 경쟁국과 비교해 상대적으로 열세인 한국의 고려인삼이 선택할수 있는 방법은 비록 생산은 적더라도 고부가가치인삼을 생산하여 명품화로 가야 할 것으로 생각된다. 명품화를 위해서는 우선 고려인삼의 효능을 밝혀 고기능성을 입증해야하고, 재배생산단계에서부터 농약, 중금속등에 노출되지 않고 병에 자유로운 청정재배를 통해 명품화를 이룩해야 하며, 특히 제품의 생산 및 유통단계에서 표준화를 통해서 전세계의 소비자가 믿고 사용할수 있도록 해야 할 것이다. 또한 인삼에만 함유된 인삼사포닌(ginsenoside)은 배당체로서 여러 미생물에 의하여 당사슬이 끊어짐으로서 새로운 사포닌이 등장하게 되는데 이러한 사포닌이 각종 함암, 면적, 치매, 관절등에 탁월한 효능을 보임으서 많은 연구들이 진행중에 있으며, 특히 인삼에만 함유된 것으로 알고 있었던 ginsenoside가 돌외(한약재명 칠엽담)에도 함유되어 있고 일부 성분은 미생물을 통해서 변환시킴으로 서 값비싼 인삼사포닌을 생장이 빠르면 비교적 값싼 돌외 사포닌으로부터 생산할수 있게 되었다. 본 세미나에서는 각종 미생물을 이용하여 인삼의 사포닌을 변환시키고 돌외 사포닌인 gypenoside를 ginsenoside로 변환시켜 대량생산할 수 있는 방법을 제시하고자 한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.5
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• pp.556-561
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• 2008

The characteristics of microwave reflectometry, which is based on the technologies of FM radar and is applied as a non-invasive method to examine the properties including density distribution of inhomogeneous media, is investigated. The microwave reflectometry system requires not only an optimized system hardware but as well as the understanding of system response from the media under test in order to provide the system solution describing the object under test quantitatively. The introduction of microwave reflectometry especially in the area of applied plasma physics has been relatively new and the number of usage is found to be increasing gradually. The experimental method to characterize the microwave system as a device to examine the properties of plasma is explained. The microwave reflectometry signals consist of the cutoff signals which originate from the region where most of the reflected power comes from and the scattered signals which result as an interaction of the microwave and the density perturbations. This paper describes the experimental results of the scattered signal from the microwave reflectometry, such as the wavenumber dependence and the sensitivity on density perturbation, and the comparison of the characteristics with those from the numerical simulations and those from the cutoff signals.