• 대한전자공학회논문지SD
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• 제47권7호
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• pp.37-43
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• 2010

영상데이터의 용량이 늘어남에 따라, 시리얼 링크의 전송속도는 점점 빨라지고 있다. 따라서 기존에 제시되었던 상용화규격도 계속해서 전송속도를 상향시킨 차기 버전을 제안하고 있다. 차기 버전은 기존 버전과 호환성을 갖춰야 하므로 두 가지 이상의 전송속도로 동작할 수 있는 송수신기 회로가 필요하다. 본 논문에서는 4개의 채널을 가지며, 3.2 Gb/s 또는 6.4 Gb/s의 전송속도로 동작하는 송신기를 설계하였다. 이 송신기는 1, 1.5, 2, 3배의 pre-emphasis를 선택적으로 사용할 수 있으며, 출력 스윙을 200, 300, 400, 600 mVdiff,p2p로 선택할 수 있다. 설계된 송신기는 $0.13{\mu}m$ CMOS 공정을 이용하여 제작되었으며, COB 패키징을 이용하여 PCB에 실장되어 검증되었다.

• 한국산학기술학회논문지
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• 제7권5호
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• pp.907-912
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• 2006

음성신호의 프리-엠퍼시스 과정은 고주파 영역의 약화된 성분을 보상하기 위해 사용되어진다. 프리-엠퍼시스 필터의 일반적인 형태는 y(n)=s(n)-A${\cdot}$s(n-1)이고, A 값은 유성음의 경우$0.9{\sim}1.0$ 사이의 값이다. 그리고, A 값은 프리-엠퍼시스의 기울기 값을 반영하고 기존의 방법에서는 R(1)/R(0)를 사용한다. 본 논문에서는 성문특성으로 인해 고주파 특성이 약화되는 것을 보상하기 위하여 새로운 평탄화 기법을 제안한다. 우선 신호 왜곡의 최소화를 위하여 QMF를 사용하였다. QMF를 사용한 후, 각 프레임별 자기상관계수를 사용하여 평탄화 과정을 수행하였다. 실험결과에서는 제안한 방법이 자기상관 방법보다 약화된 고주파 성분을 효과적으로 보상하는 평탄화 특성이 우수한 것으로 나타났다. 그러므로 평탄화 알고리즘은 음성 인식, 음성 분석 및 합성 등과 같은 음성 신호 처리 분야에 광범위하게 적용되어질 수 있다.

• 대한지구과학교육학회지
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• 제15권1호
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• pp.16-26
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• 2022

이 연구는 초등 예비교사들이 과학수업을 설계할 때 무엇에 주목하는지 알아보는 것이었다. 초등 예비교사들의 응답을 분석한 결과, 초등 예비교사들은 과학탐구를 강조하는 수업, 학생의 흥미, 수준, 오개념 처치를 고려한 수업, 일상생활과 밀접한 수업에 주안점을 두며 과학수업을 설계하고 있는 것으로 분석되었다. 특히, 초등 예비교사들은 실험 및 탐구를 강조하는 과학수업 설계에 대해 많은 언급을 한 것으로 보아 탐구를 강조하는 것이 과학수업 설계에서 중요한 점으로 인식하고 있는 것으로 나타났다. 예비교사들이 탐구를 강조하는 것과 같이 과학교육의 중요한 측면을 인식하고 있는 점은 매우 긍정적이라고 할 수 있다. 더불어 예비교사들의 교사 전문성 계발을 위해 교사 및 동료와의 협업을 통한 수업설계 및 실연 기회를 늘려가야 함을 제안한다.

• 한국초등과학교육학회지:초등과학교육
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• 제29권3호
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• pp.350-363
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• 2010

Recently there has been increasing emphasis on pedagogical content knowledge (PCK) for fostering science teachers' teaching professionalism that needs to be done from teacher training courses systematically. We investigated what were the PCK factors considered in planning instruction and the difficulties encountered in implementing it by pre-service teachers. In this study, 26 sophomores at an university of education in Gyeonggi province were asked to perform teaching demonstrations using scientific instruction models. They were also requested to write reflective journals and interview. Analyses of the results revealed that many pre-service teachers considered the teaching strategies such as the instruction organization and implementation when planning instruction. They had also regard to the learners' cognitive affective aspects, whereas the pre-knowledge of them was not properly considered. Especially, the curriculum and assessment were almost disregarded. Most of the difficulties encountered in planning instruction and implementing it were appeared in terms of the teaching strategies. For example, they had difficulties in considering the characteristics of each stage presented by the instruction models when planning instruction and implementing it. The frequencies of the difficulties in implementing experiment were especially higher than those of the other PCK factors. Educational implications of these findings are discussed.

• 한국초등과학교육학회지:초등과학교육
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• 제36권1호
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• pp.85-94
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• 2017

The purpose of this study was to investigate the perspectives of pre-service elementary teachers on science education of future by using Draw-A-Science-Teacher-Test Checklist and open-ended questionnaire. The subjects of this study were 136 pre-service elementary teachers. The results of the research are as follows. The pre-service teachers thought that the physical environment reflecting the latest science and technology for science education will be developed in the future. However, few respondents indicated that student-centered equipment or a free and creative classroom environment would be provided. Second, they predicted that there would be changes in teacher's activities due to the introduction of advanced facilities and equipment, but most of the other teachers' activities were thought to be similar to those of current teachers. Third, the pre-service elementary teachers thought that a variety of new technologies would be used in science education and science teachers would mainly teach high-technology, IT technology, science knowledge, and newly discovered science concepts. In addition, we found that pre-service elementary teachers' images were more 'teacher-centered' than 'student-centered'. These results show that pre-service elementary teachers are expected to utilize the latest science and technology actively in science education in 2030 and that it will lead to changes in the physical environment, teachers' activities, education contents, and teaching and learning methods. In addition, they viewed acquisition of science concept as an important goal of science education in the future and had different points of view from the current science education curriculum and scholars' emphasis on educational research for the future.

• 기술혁신학회지
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• 제10권3호
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• pp.580-603
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• 2007

본 연구는 출연연구기관의 기관평가요소 분석을 통해 최근까지 출연연구기관에 대한 책임성(accountability)이 어떻게 변화 및 발전되어 왔는가를 분석하고자 한다. 구체적으로 1991년부터 2005까지 기관평가요소를 연구회 설립 이전과 연구회 설립 이후 기간으로 구분하여 분석하였다. 출연연구기관에 요구되는 책임성을 법규준수 책임성, 관리적 책임성, 재무적 책임성, 사업성과 책임성, 사회적 책임성 등 다섯 가지 책임성으로 구분하여 분석한 결과, 연구회 설립이전에는 법규준수 책임성, 관리적 책임성 등이 강조되었으며, 연구회 설립 이후에는 사업성과 책임성, 관리적 책임성이 강조되었다. 법규준수 책임성과 관리적 책임성은 시간이 흐름에 따라 요구하는 구체적인 책임내용이 상당히 변화되었다. 최근에는 사업성과 책임성이 가장 중요한 책임성으로 강조되고 있으며 재무적 책임성도 연구회 설립 이후 새롭게 등장하였다.

• 정보학연구
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• 제10권3호
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• pp.77-92
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• 2007

This study aims to suggest an implementation methodology of security module for data integrity of mobile internet terminal. This is based on the WTLS(Wileless Transport Layer Security) of WAP Protocol. This security module is expected to achieve central role in conversion of wireless internet environment and emphasis of encryption technology and safe and calculable wireless communication environment construction.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권4호
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• pp.561-567
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• 2017

This paper presents a 4-channel common-cathode VCSEL driver array operating up to 6.25 Gb/s per channel for the applications of HDMI 2.0 active optical cables. The proposed VCSEL driver consists of an input buffer, a modified Cherry-Hooper amplifier as a pre-driver, and a main driver with pre-emphasis to drive a common-cathode VCSEL diode at high-speed full switching operations. Particularly, the input buffer merges a linear equalizer not only to broaden the bandwidth, but to reduce power consumption simultaneously. Measured results of the proposed 4-channel VCSEL driver array implemented in a $0.13-{\mu}m$ CMOS process demonstrate wide and clean eye-diagrams for up to 6.25-Gb/s operation speed with the bias current 2.0 mA and the modulation currents of $3.1mA_{PP}$. Chip core occupies the area of $0.15{\times}0.1{\mu}m^2$ and dissipate 22.8 mW per channel.

• 대한기계학회논문집
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• 제19권2호
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• pp.402-407
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• 1995

The effects of room temperature and strain aging treatment are discussed on the critical condition for the onset of growth of non-propagating cracks on 0.15% C low carbon steel, with special emphasis on the length of the critical non-propagating crack and on the crack opening displacement(COD) at the crack tip. It is found from the experimental analysis that room temperature and strain aging of a fatigue pre-cracked specimen introduced the closure of a crack tip of the pre-crack and the reduction of crack opening displacement at the wake of crack, together with an improvement in crack growth resistance of the microstructure. This may cause an increase in the endurance limit of the specimen, through the enhancement of effective stress for the onset of growth of the critical non-propagating crack.

• 한국표면공학회지
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• 제35권5호
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• pp.279-288
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• 2002

Zinc phosphating for cold forming of steel was studied with emphasis on decreasing phosphating temperature. To lower phosphating temperature, some techniques, such as adding Cu ion into bath, using activator in the form of pre-dip, and aeration in bath, instead of using conventional accelerator, namely oxidizing agent, have been tried. It was revealed that phosphating, leading to coatings of Improved uniformity and fine crystal size, can be carried out using above techniques at lower temperature ($55^{\circ}C$) compared to conventional phosphating temperature ($80 ~ 90^{\circ}C$ ). Under present condition, it was seen that optimum concentrations of Cu ion in phosphating bath and activator in pre-dip are 0.015% (w/w) and 2.0 g/1, respectively. The coating weight was within the range of 15 ~ 20 g/$\m^2$. When lubricant was applied into phosphating coatings, the amount of lubricating component (total soap) was found to be 6 ~ 10 g/$\m^2$ and the lubricated panel revealed excellent lubricating properties.