• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• 제2B권3호
• /
• pp.100-108
• /
• 2002

A simple sustain driver employing an energy recovery function is proposed as a highly efficient driver of a plasma display panel. The proposed driver uses dual resonance in the sustaining mode operation: a main resonance between an inductor and an external capacitor to produce alternative pulses and a sub-resonance between an inductor and a panel to recover the energy consumption by the capacitive displacement current of the PDP. The operational principle and design procedure of the proposed circuit are presented with theoretical analysis. The operation of the proposed sustain driver is verified through simulation and experiments based on a 7.5-inch-diagonal panel with a 200 KHz operating frequency.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
• /
• pp.35-37
• /
• 2002

Most of the inhabitants living near power line complain wind noise from power line to be problems they can feel directly if there is no countermeasure to remove noise basically. Wind noise from power line happens by tower, insulators, conductor and others in their operating individually or complexly. Wind noise show us several forms like whistle, siren and bullfrog croaking as height of noise source is high and elastic wave tone with low frequency. This paper shows actual conditions and occurrence cause which may be investigated and analyzed on the wind noise, and also prepares mitigation methods and introduces a working sample to reduce a wind noise.

• Journal of Information Technology Applications and Management
• /
• 제13권2호
• /
• pp.1-15
• /
• 2006

This paper classifies the critical knowledge/skill set required to IS practitioners according to content or domain of knowledge : IS technology knowledge/skills, organizational and societal knowledge/skills, interpersonal knowledge/skills, and personal traits knowledge/skills. The survey reveals that Korean IS practitioners rate interpersonal knowledge/skills and personal traits knowledge/skills the most important, and organizational and societal knowledge/skills the least important. Specifically, they rate creative thinking, critical thinking, interpersonal communication skills, team working skills, personal motivation, operating systems, programming languages, DB/data warehouse, IS technological trend, networkicommunicationisecurity especially important. The survey also shows that Koran IS practitioners feel knowledge deficiency in almost all knowledge/skills areas. The results confirm that the curriculum of universities, the training and education programs of industries, and IS/IT education policy of the government should be revised as soon as possible.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 춘계합동학술대회 논문집
• /
• pp.1-5
• /
• 2002

The sustain driver for AC plasma display panel should provide alternating high voltage pulses to ignite plasma and recover the energy discharged from the intrinsic capacitance between the scanning and sustaining electrodes inside the panel. In this paper, an efficient sustain circuit employing boost-up function is proposed to achieve a faster rise-time in order to be suitable to widely used the address display period separated (ADS) driving method. The proposed circuit improves the recovery efficiency, regardless of the variation of the panel capacitance. The principle of operation, features, and simulated results are illustrated and verified on a 7.5-inch diagonal panel at 200 [kHz] operating frequency based on experimental prototype.

• Journal of Information Science Theory and Practice
• /
• 제9권4호
• /
• pp.63-74
• /
• 2021

Virtual Reality (VR) is one of the core components of the fourth industrial revolution as a technology that makes the virtual world feel as if it is real. VR is being used in various fields such as entertainment, advertisement, education, medical care, training, sports, and tourism, as well as providing contents for such things as games and videos. Libraries are already looking for ways to utilize VR from various angles, such as operating experiential programs. The purpose of this thesis is to develop and propose a VR-based library user education program. In order to achieve the purpose of the study, we analyzed previous studies from a theoretical perspective to find a way to construct a user education program, and also to derive possible implications based on examples of countries such as the United States and Korea that are already introducing and applying VR technology to library services. Therefore, the user education program proposed in this study can be used as a basic building block when many libraries want to develop VR-based programs in the future.

• 실천공학교육논문지
• /
• 제5권2호
• /
• pp.169-176
• /
• 2013

최근 시뮬레이션 환경 구축은 모든 분야에 걸쳐서 중요한 이슈로 떠오르고 있다. 특히 비행기나 우주선과 같은 한 번 작동 하는데 많은 비용이 드는 기기의 훈련일 경우, 실제 기기와 같은 환경을 시뮬레이터로 구축하여 놓음으로써 막대한 비용의 절감과 함께, 실전에서와 같은 훈련 효과를 가져올 수가 있다. 이에 우리는 일반 운전학원에서 운전 면허 획득을 위한 연습시 차량의 부족과 많은 인원으로 인해 대기 시간이 많이 지연되고 있음에 착안하여, 운전 연습에 맞는 시뮬레이터를 개발한다. 운전 연습에 적합한 시뮬레이터인 3D 레이싱 게임에 착안하여, 운전 면허 실습을 위한 컴퓨터 3D시뮬레이션 모델을 제안하고, 이를 사용하여 사람들이 실제 운행을 하는 것처럼 핸들을 조작하는 시뮬레이션 환경을 제공한다. 본 논문은 컴퓨터 3D 시뮬레이션을 활용하여 운전 연습 모델을 모델링하고, 이 모델링을 사용하여 시뮬레이터를 제작하여 활용하는 것에 관한 연구이다.

• 전기전자학회논문지
• /
• 제23권1호
• /
• pp.254-260
• /
• 2019

본 논문에서는 양방향 dc-to-dc 컨버터의 고장원인, 고장영향, 고장 결과를 파악하기 위한 failure mode and effect analysis(FMEA)와 양방향 컨버터의 위험도를 고려한 fault-tree analysis(FTA)를 통해 고장률을 예측한다. 전기차의 구동전압을 효율적으로 상승시키기 위해 인버터 앞단에 부착되는 양방향 컨버터는 배터리 전력을 dc-link 커패시터로 방전시키는 승압모드와 회생전력을 배터리로 충전시키는 강압모드를 가진다. 양방향 컨버터의 동작 특성을 고려한 FMEA 결과를 바탕으로 컨버터의 위험도를 고려한 고장나무를 설계한다. 전기차 MCU용에 맞는 설계 파라메타를 설정하고 출력전압 리플과 인덕터 전류 리플에 따른 커패시터와 인덕터의 부품 고장률을 분석한다. 또한 동작 온도에 따른 주요부품의 고장률을 MIL-HDBK-217F를 이용하여 구한다. 마지막으로 부품 고장률을 고장나무의 기본 사상의 고장률로 반영하여 컨버터 고장률과 평균고장시간을 예측한다.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
• /
• 제16권12호
• /
• pp.1249-1253
• /
• 2010

개인용 컴퓨터의 성능이 향상되면서 대부분의 컴퓨터 사용자에게 여러 개의 애플리케이션을 구동시키는 다중작업은 일반화되었다. 윈도우즈 운영체제는 다중작업 중인 여러 애플리케이션을 구동할 작업공간을 오직 하나만 제공하고 있기 때문에 많은 사용자들이 불편함을 느끼고 있다. 본 논문에서는 이러한 윈도우즈 운영체제의 단점을 보완하여 윈도우즈 운영체제 환경에서 사용자에게 여러 작업공간을 제공하며, 리눅스 Compiz와 같이 사용자에게 화려하고 직관적인 UI(User Interface)를 제공하기 위해 DirectX를 이용하여 작업공간의 전환 과정을 3D 모션으로 보여줄 수 있는 3D 가상 데스크톱을 제안한다.

• 한국초등과학교육학회지:초등과학교육
• /
• 제32권1호
• /
• pp.47-59
• /
• 2013

The purpose of this study is to investigate the perception about STEAM education of primary teachers who have developed and applied STEAM education to their students through teacher training program. For this study, 101 among 172 attendance are responded to questionnaire of three categories consisting of development and application teaching material for STEAM instruction, and spreading STEAM education. The major findings are as follows: First, when primary teachers develop materials for STEAM education, they consider applicabilities in real classes. Second, they feel the burden of time when they develop STEAM material. Third, they think that their own program has significant educational effectiveness and that students enjoyed the program. Especially, they think that STEAM education program can raise students' interest about learning. Fourth, primary teachers point out the constraints for application of STEAM education program, which are lack of expertise and difficulty acquiring class time. Fifth, primary teachers evaluate the effect of STEAM education program on primary education is positive, and they answer that we need many teaching materials for STEAM education, operating as a regular curriculum, and securing budget. In order to spread STEAM education in field of primary education successfully, administrators have to consider and reflect the voice of teachers.

• 한국정밀공학회지
• /
• 제28권11호
• /
• pp.1259-1264
• /
• 2011

This paper suggests a new film-type haptic actuator based on cellulose acetate electro-active paper. Conventional tiny haptic actuators in mobile devices can create vibrotactile sensation at only near resonant frequency. The strategy of operating near the resonant frequency, however, brought a new issue for creating vibrotactile sensation which can be strong enough to feel in arbitrary frequency. Another problem is that the size of the conventional actuator is not small enough to be embedded into slim mobile devices. In order to achieve these issues, we propose a thin and tiny actuator based on a cellulose acetate material charged with an electric potential. The motion of the actuator can be a concave or a convex by controlling a polarity of both charged membranes and the actuator performance can be modulated by increasing level of biased electric potential.