• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.394-397
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• 2003

In this paper, we have proposed a clock recovery algorithm of OFDM/QPSK-DMR(Orthogonal Frequency Division Multiplexing/Quadrature Phase Shift Keying Modulation-Digital Microwave Radio)system using BL-PSF(Band Limited-Pulse Shaping Filter) and have analyzed the clock phase error variance performance of OFDM/QPSK and single carrier DMR systems. The existing OFDM/QPSK-DMR system using the windowing requires training sequence or CP(Cyclic Prefix) to synchronize a receiver clock frequency Because there is no training sequence or CP(Cyclic prefix) in our proposed DMR system, the proposed clock recovery algorithm is useful to the OFDM/QPSK-DMR system using BL-PSF, The simulation results confirm that the proposed clock recovery algorithm has the same clock phase error variance performance in a single carrier DMR system under AWGN(Additive White Gaussian Noise) environment.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.384-388
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• 2003

In this paper, we have proposed a OFDM/QPSK-DMR(Orthogonal frequency Division Multiplexing/Quadrature Phase Shift Keying Modulation-Digital Microwave Radio)system using BL-PSF(Band-limited pulse shaping filter) over the Microwave channel. In the proposed DMR system, STS-1(51.84 Mbps) of SONET(Synchronous Optical NETwork) is first modulated by OFDM/QPSK symbol and used Band-limited pulse shaping filter. The advantage of the proposed DMR system is to simplify system complexity and increase IFFT/FFT block use-efficiency. The system performance of single carrier and OFDM systems is already proved that those of DMR systems have the same performance over AWGN(Additive White Gaussian Noise) channel environment. Therefore, the system is analyzed between proposed OFDM/QPSK-DMR and single carrier DMR systems and simulated by BER performance and Signature curve over Microwave channel environment. Simulation result is that the proposed system performances are approaching to the performance of single carrier DMR system as the number of Sub-carriers increasing.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.304-306
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• 2003

In this paper, we propose the intelligent robot control technique for mobile robot using personal digital assistants (PDA). With the proposed technique, the mobile rebot can trace human at regular intervals by the remote control method with PDA. The mobile robot can recognize the distances between it and human whom the robot must follow with both multi-ultrasonic sensors and PC-camera and then, can inference the direction and velocity of itself to keep the given regular distances. In the first place, the mobile robot acquires the information about circumstances using ultrasonic sensor and PC-camera then secondly, transmits the data to PDA using wireless LAN communication. Finally, PDA recognizes the status of circumstances using the fuzzy logic and neural network and gives the command to mobile robot again.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1555-1558
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• 2005

In this study, we measured cylindricity and Runout of the air bearing spindle, and tested PCB(printed circuit boards) drilling with 0.4mm micro drill at 90,000rpm and 110,000rpm in order to obtain drilling hole error. Results are as follows; The air bearing spindle's Runout was not so high within $10\mu{m}$ from 20,000rpm to 80,000rpm but it grew after 80,000rpm. Drilling hole size error was 9% at 80,000rpm and 12% at 110,000rpm because of spindle's Run out. Drilled hole shape falsified more 110,000rpm than 90,000rpm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1261-1264
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• 2005

Recently, as researches and developments for milli-structure and micro machine are actively progressing, manufacturing technologies and skills for tiny small machine parts are getting more important. So, we have been trying to cut using high revolution air bearing spindle and micro-endmill, and studying for magnitude of cutting force, cutting force wave form and surface roughness. We figured out that in 60,000rpm is so slow that cutting is not perfact. Chatter occured to $2\mu{m}/rev\;at\;80,000rpm\;and\;4.4\mu{m}/rev$ at 100,000rpm. We confirmed that spindle run out increased surface roughness at high revolution.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.70.3-70
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• 2002

This paper presents a procedure of implementing a robust controller for a paper-making plant in DCSs. A paper-making process generally has triple problems to automatically tune its output qualities . Long transport delays which are not able to be simply linearized. The transfer matrix of the process is not square. And every plant model has some uncertainty in low and middle frequency region. To tackle these problems, a multi-input / multi-output (MIMO) plant model having some uncertainty was derived by considering some physical and mechanical principles of the process. Then a MIMO robust-controller is designed and implemented in a real DCS as function block type. Some special co...

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.243-245
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• 2001

The reliability and probabilistic generation production cost evaluation of composite power systems are important for power system operation and expansion planning. This paper present a computer program which can evaluate the reliability and probabilistic generation production cost of composite power system using GUI(Graphic User Interface). In this computer program, Monte Carlo simulation methods and CMELDC(CoMposite power system Effective Load Duration Curve) were used.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.07a
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• pp.733-734
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• 2023

코로나 펜데믹 이후 다시 대면활동이 활성화되고 있지만 이미 학습한 비대면 활동은 10대들의 대안적인 활동, 소통, 협업의 공간으로 메타버스가 주목을 받으며 초,중 대학에 이르는 교육영역에 대한 논의와 연구가 활발해지고 있다. 특히 고가의 장비나 사용하기 위험한 교육 교보재를 메타버스 공간에 같이 공유하여 오프라인에서 쉽게 접할 수 없는 확장된 사용자 경험을 제공하기 위한 니즈가 있다. 이에 교육 공간으로서의 메타버스 활용을 뛰어넘어 고가 및 위험성이 있는 제한된 교육경험을 제공할 수 있어야 한다.

• Journal of The Korean Association of Information Education
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• v.23 no.4
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• pp.363-374
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• 2019

Recently, there is an increasing interest in game based learning as a teaching method for digital native learners. This study set kinect game contributes to engaged learning as the competition and cooperation play (achievement goals, interaction), the digital game play (multisensory stimulation, fantasy and curiosity, chance, accurate feedback, control), and the body movement play (embodied cognition, presence). After performing classes using the motion recognition game developed for the elementary school history class, this study conducted semi structured interviews based on engaged learning elements of kinect game based learning for students who were successfully participating in learning. In the result, each element appeared to a successful learner. Based on these results, this study hopes to assist researchers as a basic evidence to introduce kinect game-based learning for engaged learning.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.1-12
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• 2020

This is a study on the direction of the teaching support program contents analysis and teaching support platform of the teaching and learning center. To this end, in April 2020, a literature study was conducted, an analysis of the current status of teaching support at other universities and K universities, an analysis of professor interviews, and expert verification were conducted. The main research results are as follows. First, as a result of examining the current status of teaching support programs at 24 universities, it was confirmed that special lectures on teaching methods, class consulting, teaching method research meetings, and educational resource rooms were operated as representative programs. Second, the basic structure of the platform is composed of a lecture case sharing bulletin board to enable active exchange of opinions on teaching methods among teachers, a teaching support program application bulletin board to enable application for a teaching method program, and Edu-tech to activate the platform, and a professor support menu. Third, the contents of the teaching support platform were implemented based on the basic structure of the teaching support platform. This study analyzed the contents of the teaching support program and conducted a study to suggest the direction of the teaching support platform to discuss the direction of establishing an effective teaching support platform.