• Title/Summary/Keyword: 정동욱

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Needs Analysis for Teacher Education System in Ubiquitous Era (유비쿼터스 시대의 교사양성체제에 대한 예비교사 요구 분석)

  • Park, Jung-Hwan;Park, Hyung-Sung;Cheong, Dong-Uk;Kang, Soon-Mee;Moon, Chang-Bae;Cho, Jung-Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.1
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    • pp.264-271
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    • 2010
  • The purpose of this study is to analyze the needs for new teacher education systems. Through this needs analysis, teachers can evolve in the educational environment in a new learning era based on the substance of novice teacher educational systems. Based on the various pedagogical needs in the field of education, we have to supplement the current teacher education systems in the areas of educational philosophy, teachers' teaching abilities, recognition and understanding for the importance of educational content (curriculum creation), and diversity about communication methods between teacher and student.

Design and Estimation of a Session Key based Access Control Scheme for Secure Communications in IoT Environments (IoT 환경에서 안전한 통신을 위한 세션 키 기반 접근 제어 기법의 설계 및 평가)

  • Jin, Byungwook;Jung, Dongwoog;Cha, Siho;Jun, Moonseog
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.12 no.1
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    • pp.35-41
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    • 2016
  • Internet of Things (IoT) services are widely used in appliances of daily life and industries. IoT services also provide various conveniences to users and are expected to affect value added of all industries and national competitiveness. However, a variety of security threats are increased in IoT environments and lowers reliability of IoT devices and services that make some obstacles for commercialization. The attacks arising in IoT environments are making industrial and normal life accidents unlike existing information leak and monetary damages, and can expand damage scale of leakage of personal information and privacy more than existing them. To solve these problems, we design a session key based access control scheme for secure communications in IoT environments. The proposed scheme reinforces message security by generating session key between device and access control network system. We analyzed the stability of the proposed access scheme in terms of data forgery and corruption, unauthorized access, information disclosure, privacy violations, and denial of service attacks. And we also evaluated the proposed scheme in terms of permission settings, privacy indemnity, data confidentiality and integrity, authentication, and access control.

Economic Design of $\bar{X}$-Control Charts with Warning Limits under Weibull Failure Model (와이블 고장모형 하에서 경고한계를 고려한 $\bar{X}$ 관리도의 경제적 설계)

  • Jeong, Dong-Wook;Lee, Joo-Ho
    • Journal of Korean Society for Quality Management
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    • v.40 no.2
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    • pp.186-198
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    • 2012
  • Since Duncan(1956) first proposed an economic design of $\bar{X}$-control charts, most of the succeeding works on economic design of control charts assumed the exponential failure model like Duncan. Hu(1984), however, assumed a more versatile Weibull failure model to develop an economic design of $\bar{X}$-control charts and Banerjee and Rahim(1988) further improved Hu's design by changing the assumption of fixed-length sampling intervals to variable-length ones. In this article we follow the approach of Banerjee and Rahim(1988) but include a pair of warning limits inside the control limits in order to search for a failure without stopping the process when the sample mean falls between warning and control limits. The computational results indicate that the proposed model gives a lower cost than Banerjee and Rahim's model unless the early failure probability of a Weibull distribution is relatively large. The reduction in cost is shown to become larger as the cost of production loss outweighs the cost of searches for a failure.

Developing a physical environment and a procedural model for pre-service teachers' teaching practice in 3D virtual reality (3D 가상현실에서 예비교사의 수업연습을 위한 물리적 환경 및 절차적 모형 개발)

  • Cheong, Dong-Uk
    • Proceedings of the KAIS Fall Conference
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    • 2009.05a
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    • pp.393-396
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    • 2009
  • 본 연구의 목적은 3D 가상공간인 세컨드라이프에서 예비교사의 성공적인 수업연습을 위한 물리적 환경 및 절차적 모형을 개발하는 것이다. 이를 위해 본 연구에서 수행한 내용은 다음과 같다. 첫째, 수업 연습 관련 이론 탐색 및 문헌 연구를 통해 성공적인 수업연습을 위한 필수조건들을 탐색하였으며, 이 조건들로부터 수업연습을 위한 절차적 모형의 시안을 개발하였다. 둘째, 세컨드라이프에서 수업연습을 위해 필요한 교실의 물리적 구성요소를 개발하였다. 개발된 교실의 물리적 구성요소는 교실공간, 칠판, 교사용 책걸상, 학생용 책걸상, 출입문, 창문, 게시판, 프리젠테이션 도구 등이었다. 셋째, 세컨드라이프에서 수업연습을 위해 필요한 의사소통 도구를 탐색하였다. 탐색 결과, 텍스트 대화 도구, 음성 대화 도구, 노트카드 사용 도구, 공지사항 사용 도구 등이 의사소통을 위해 필요한 요소로 결정되었다. 마지막으로, 세컨드라이프내의 교실 안에서 의사소통 도구를 활용하여 예비교사의 수업연습을 수행하였다. 이 수행결과에 기반하여 세컨드라이프에서의 예비교사의 수업연습을 위한 절차적 모형을 완성하였다. 이 연구는 예비교사들에게 실제적 수업연습(field-based teaching practice)에 앞서, 3D 가상공간인 세컨드라이프에서 실험적 수업연습(laboratory-based teaching practice) 경험을 가능하게 하였다는 점에서 의미가 있다.

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Developing a Simulator for Practicing Discipline Skills of Pre-service Teachers (예비교사의 훈육기술 연습을 위한 시뮬레이터 개발)

  • Cheong, DonGuk;Kim, SunHwa
    • The Journal of Korean Association of Computer Education
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    • v.12 no.3
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    • pp.63-74
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    • 2009
  • The purpose of this study was to design and develop the simulator for practicing pre-service teachers' classroom discipline skills to control and prevent misbehaviors of students. In order to accomplish this purpose, the followings were researched. First, the examination of related literature and previous studies was performed to find out whether teaching simulation can be significant for pre-service teacher' teaching experience. Second, self-esteem, self-confidence, and self-control were selected as key variables of students' misbehaviors from the examination of literature and previous studies. Third, students' misbehaviors were designed and their information in the student records was developed based on the variables. Forth, teacher's treats were developed and classified with verbal and nonverbal treats. Lastly, simulated students' misbehaviors were designed to be aggravated or prevented according to the teachers' treats. Further research for a teaching simulation was projected based on the pre-service teachers' evaluation.

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Study of ARS using Ring Laser Gyro (Ring Laser Gyro를 이용한 ARS에 관한 연구)

  • Jeong, Sang-Ki;Choi, Hyeung-Sik;Ji, Dae-Hyeong;Jung, Dong-Wook;Kwon, O-Soon;Shin, Chang-Joo;Seo, Jung-Min
    • Journal of Ocean Engineering and Technology
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    • v.31 no.2
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    • pp.164-169
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    • 2017
  • Studies were performed on an ARS using SDINS's RLG and the geomatic sensor. To develop the ARS, experiments were performed to determine the characteristics of the RLG and geomatic sensor. Based on the results, to reduce the angular position errors of the RLG, which accumulate from the angular velocity data, an algorithm was studied that uses the Extended Kalman filter (EKF) to compensate the RLG data and geomatic sensor data. To verify the performance of the developed algorithm for reducing the cumulative angular errors, experiments that included the developed EKF were performed. Through these, it was shown that a drastic reduction in the angular errors of the RLG were achieved.

Effect of Unbalance on Vibration and Machining of Al6061 Aluminum Alloy in Precision Rotator (정밀회전체의 언밸런스 변화에 따른 진동과 Al6061 알루미늄 합금 가공에 미치는 영향)

  • Kim, Min Soo;Kim, Jung Tae;Park, Seok Woo;Jeong, Dong Uk;Choi, Sun Ho;Koo, Bon Heun;Yoon, Sang Hwan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.3
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    • pp.76-82
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    • 2021
  • At present, with the development of precision instruments, high dimensional accuracy of workpieces must be ensured. In particular, for the aluminum alloys used in automobiles, the surface roughness of the workpiece is extremely important. The dimensional accuracy and surface roughness of the workpiece is considerably affected by the rotational accuracy of the rotor. Therefore, to enhance the rotational accuracy, various variables such as those related to the components such as bearings, motors, and end mills, rotational speeds, and vibrations must be considered. In this study, the difference in the quality of the workpieces was compared considering the weight imbalance and rotational speed as variables.

A Data Use and Management Policy in the Public Sector (공공부문에서의 데이터 이용 및 관리 방법)

  • 김진형;김영갑;신성욱;변현진;신신애;이헌중;정동원
    • Proceedings of the Korean Information Science Society Conference
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    • 2004.10b
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    • pp.169-171
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    • 2004
  • 국내 공공부문에서의 통합적인 다양한 서비스 제공을 위해서 여러 가지 노력과 연구가 진행되고 있다. 통합 서비스를 제공하기 위해서는 사용자에게 제공되는 정보들 간의 일관성 있는 구축, 관리 및 운용을 위한 DRM에 대한 연구가 필수적으로 요구된다. 이미 미국, 영국 등 선진국에서는 DRM 개발을 위한 연구가 계속적으로 진행되어 왔으며, 국내에서도 이러한 중요성을 인식하여 현재 한국형 DRM 개발을 위한 사전 연구를 진행하고 있다. 이 논문에서는 DRM 개발을 위한 주요 내용 중 응용, 사용자, 기판 등에 따라 달라지는 정보 접근을 체계적으로 관리할 수 있는 이용 관리 정책에 초점을 둔다. 다양한 측면에서 정보에 대한 접근성을 고려하고 이러한 규칙을 기술하고 관리하는 방법에 대하여 기술한다.

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A Characteristic Analysis of High Voltage Flyback Converter including Resonant Element (공진요소를 포함한 고전압 플라이백 컨버터의 특성해석)

  • Jung, Dong-Yeol;Lee, Jae-Kwang;Hong, Sung-Soo;Han, Sang-Kyoo;SaKong, Sug-Chin;Roh, Chung-Wook
    • The Transactions of the Korean Institute of Power Electronics
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    • v.13 no.3
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    • pp.186-195
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    • 2008
  • This paper studies the operating characteristics of the high voltage flyback converter including the resonant elements. The detailed mode analysis and the design procedure are presented in designing a high voltage flyback converter. To verify and to confirm the validities of the presented analysis and design procedure, the computer simulation and the experiments have been performed.

Polarity Inversion DC/DC Power Conversion Power Supply with High Voltage Step-up Ratio (고전압 변환비치 극성 반전형 DC/DC 전력 변환 전원장치)

  • Jung, Dong-Yeol;Jung, Yong-Joon;Hong, Sung-Soo;Han, Sang-Kyoo;SaKong, Sug-Chin;Roh, Chung-Wook
    • The Transactions of the Korean Institute of Power Electronics
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    • v.13 no.3
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    • pp.196-205
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    • 2008
  • A noble polarity inversion dc/dc power conversion circuit that has the high input-output voltage conversion ration characteristics is presented for high voltage DC power supply applications. The proposed circuit features the reduced voltage stresses of the component compared to those of the conventional ones. The operational principles of the proposed circuit is analyzed and comparative features are presented. The simulation results and experimental results are presented to verify the validity of the proposed circuit.