• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.7
• /
• pp.37-43
• /
• 2010

As the speed of A/V streaming, the transmission-speed requirement of serial link is continuously increasing. Consequently, commercial standards, which are released previously, are increasing transmission speed in their newly-updated versions. The flexibility between previous and updated versions is very important requirement, therefore, the transceiver which can operates at more than one data rate is important market demand. This paper demonstrates 4-channel 3.2/ 6.4 Gbps transmitter, which is capable of selecting 1, 1.5, 2, and 3 times of pre-emphasis and 200, 300, 400, and 600 mVdiff,p2p of output swing. The prototype chip was fabricated using $0.13{\mu}m$ CMOS process. Its performances are verified on PCB using COB packaging.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.5
• /
• pp.907-912
• /
• 2006

Pre-emphasizing the speech compensates for falloff at high frequencies. The most common form of pre-emphasis is y(n)=s(n)-A${\cdot}$s(n-1), where A typically lies between 0.9 and 1.0 in voiced signal. And, this value reflects the degree of pre-emphasis and equals R(1)/R(0) in conventional method. This paper proposes a new flattening method to compensate the weaked high frequency components that occur by vocal cord characteristic. We used QMF(Quardrature Mirror Filter) to minimize the output signal distortion. After using the QMF to compensate high frequency components, flattening process is followed by R(1)/R(0) at each frame. Experimental results show that the proposed method flattened the weaked high frequency components effectively than auto correlation method. Therefore, the flattening algorithm will apply in speech signal processing like speech recognition, speech analysis and synthesis.

• Journal of the Korean Society of Earth Science Education
• /
• v.15 no.1
• /
• pp.16-26
• /
• 2022

This study was to investigate what pre-service teachers pay attention to when designing science lessons. As a result of analyzing the responses of pre-service teachers, it is analyzed that pre-service teachers are designing science lessons with emphasis on science inquiry, considering students' interest, level, and treatment of misconceptions, and closely related to daily life. In particular, it was found that elementary school pre-service teachers made a lot of comments on science class design that emphasizes experimentation and inquiry, so it was found that emphasizing inquiry was recognized as an important point in science lesson design. It is very positive that pre-service teachers recognize important aspects of science education, such as emphasizing inquiry. In addition, it is suggested that the opportunities for class design and demonstration through collaboration with teachers and colleagues should be increased for pre-service teachers' professional development of teachers.

• Journal of Korean Elementary Science Education
• /
• v.29 no.3
• /
• pp.350-363
• /
• 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.

• Journal of Korean Elementary Science Education
• /
• v.36 no.1
• /
• pp.85-94
• /
• 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.

• Journal of Korea Technology Innovation Society
• /
• v.10 no.3
• /
• pp.580-603
• /
• 2007

This paper examines accountability trend for government supported research institutes through the analysis of what aspects of accountability have been emphasized in the institute evaluation from 1991 to 2005. We divided research period into pre-research council period(1991-1998) and post-research council period(1999-2005). In pre-research council period, we find four kinds of accountability for government supported research institutes, that is, compliance accountability for regulation, managerial accountability, performance accountability and social accountability and great emphasis has been put on compliance accountability for regulation and managerial accountability. In post-research council period, financial accountability for soundness has been added to the above four kinds of accountability and great emphasis has been put on performance accountability and managerial accountability, especially performance accountability. The concrete contents of an accountability has been also changed between pre-research council period(1991-1998) and post-research council period(1999-2005). Regulation accountability in the pre-research council period are related to conforming to government rules for institute operation and regulation defining institute function for reformulation, but in post-research council period, it has been focused on rules for the rationalization of management. Managerial accountability has been changed from emphasizing on management efficiency approximately to focusing on more specific management efficiency like the appropriateness of personnel management, the efficiency of budget management and project management, reasonableness of evaluation and compensation. Performance accountability has been changed in methods for measuring performance, in the pre-research council period, it has been taken quantitative method for measuring productivity, but, in post-research council period, qualitative approach like objective management has been complemented. Finally, accountability for government supported research institutes has been changed towards being concrete in many sided accountabilities and focusing on performance accountability.

• The Journal of Information Technology
• /
• v.10 no.3
• /
• pp.77-92
• /
• 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
• /
• v.17 no.4
• /
• pp.561-567
• /
• 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.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.2
• /
• pp.402-407
• /
• 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.

• Journal of the Korean institute of surface engineering
• /
• v.35 no.5
• /
• pp.279-288
• /
• 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.