• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.2B no.3
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• pp.100-108
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• 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.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.35-37
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• 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
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• v.13 no.2
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• pp.1-15
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• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.1-5
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• 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
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• v.9 no.4
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• pp.63-74
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• 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.

• Journal of Practical Engineering Education
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• v.5 no.2
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• pp.169-176
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• 2013

Recently the construction of simulation environment is an important issue in all fields. In case of the training for operating machines such as airplanes or spaceships which cause a huge cost, simulators could be helpful to reduce the costs and training efforts by simulating real situations. When people get a driver's license, too many trainees have to wait for their turns because of the limited number of cars and the small space of training sites. To solve this problem, we have designed and developed the basic design for the simulators. We suggest the Computer 3D Simulation Model for a driver's practice. The concept of this simulator is from a 3D Racing-game which suits for a driving exercise. We provide users with handle-controlled simulation settings to let users feel reality as if they drive in real through this simulator. We also use a 'force-feedback' system which gives handle vibration when users collide against obstacles or exceed lanes. Users can be absorbed in the simulation program and feel the sense of the real. This paper is the study about modeling the driving exercise model of 'computer 3D simulation', and producing and utilizing the simulator through this modeling.

• Journal of IKEEE
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• v.23 no.1
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• pp.254-260
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• 2019

The failure rate of bidirectional dc-to-dc converter is predicted through the failure mode and effect analysis (FMEA) and the fault-tree analysis (FTA) considering the operational risk. In order to increase the driving voltage of the electric vehicle efficiently, the bidirectional converter is attached to the front of the inverter. It has a boost mode for discharging battery power to the dc-link capacitor and a buck mode for charging the regenerative power to the battery. Based on the results of the FMEA considering the operating characteristics of the bidirectional converter, the fault-tree is designed considering the risk of the converter. After setting the design parameters for the MCU for the electric vehicle, we analyze the failure rate of the capacitor due to the output voltage ripple and the inductor component failure rate due to the inductor current ripple. In addition, we obtain the failure rate of major parts according to operating temperature using MIL-HDBK-217F. Finally, the failure rate and the mean time between failures (MTBF) of the converter are predicted by reflecting the part failure rate to the basic event of the fault-tree.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.12
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• pp.1249-1253
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• 2010

As personal computers have been recently improved in performance, the multi tasking of running several applications at the same time has been generalized. Since only one task space is provided for performing such tasks on Windows operating system, a number of computer users feel inconvenient. In this paper, we propose a 3D Virtual Desktop System which can show a process of switching task spaces in 3D motion using DirectX. The proposed system can provide a computer user with more task spaces and the intuitive UI(User Interlace) such as Compiz of Linux.

• Journal of Korean Elementary Science Education
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• v.32 no.1
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• pp.47-59
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• 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.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.11
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• pp.1259-1264
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• 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.