• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2543-2545
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• 2003

This paper presents a web-based virtual classroom which can be creating efficiencies in the learning process of PHP language. The proposed flash animations which explain the important principles of several topics for PHP language are designed for the learners to easily understand by executing them through simple mouse clicks. The proposed flash animations enables the learners to achieve efficient and interesting self-learning since the learning process is designed to enhance the multimedia capabilities on the basis of various educational technologies. Also, internet-based on-line voice presentation and its related texts together with moving images are synchronized for efficient, language learning process. Through the proposed virtual classroom, the learners will be capable of learning the concepts related to PHP language and its coding. The results of this paper are to allow the implementation of an efficient virtual classroom, and are also expected to make a contributions to the activation of internet-based educational systems.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.1
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• pp.74-80
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• 1996

This paper describes current controlled PWM technique of PM synchronous motors for a wide variety of speed control applications. They are however limited in their ability to operate in the power limited regime where the available torque is reduced as the speed is increased above its base value. This paper reviews the operation of the PMSM drives when they are constrained to be within the permissible envelope of maximum inverter voltage and current to produce the rated power and to provide this with the highest attainable rotor speed. The optimal field-weakening control algorithm is the use of phase current and d-axis current feedback to reduce of error between the d-axis current command and real current and to improve the torque characteristics. The improved torque characteristics of speed control strategy with optimal field weakening control algorithm is analyzed and the performance is investigated by the computer simulation and experimental results. (author). refs., figs.

• Annual Conference of KIPS
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• 2004.11a
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• pp.497-500
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• 2004

가상현실은 현실세계에서 경험하기 어려운 환경을 간접적으로 경험할 수 있는 가상의 공간이다. 이러한 가상현실에는 건물, 지형, PC(Playable Character), NPC(Non-Playable Character)등의 다양한 객체들이 존재하게 되며, PC와 NPC와 같은 객체들은 현실감을 주기 위해 인공지능을 가지게 된다. 현재까지 인공지능에 대한 많은 연구가 진행되었으며, 다양한 분야에서 활용되고 있다. 가상현실에서는 유한상태 기계(Finite Sate Machine, FSM), 유전자 알고리즘, 신경망 알고리즘 $A{\ast}$ 알고리즘 등이 활용되고 있으며, FSM은 비교적 알고리즘이 간단하고, 다른 알고리즘에 비해 구현이 간단해 널리 이용되고 있다. 본 논문에서는 FSM을 활용하여 여러 행동 패턴을 정의하고 행동 패턴간 천이가 이루어 짐으로, 객체의 행동을 다양하게 나타낼 수 있는 Multiple FSM은 제안한다.

• Annual Conference of KIPS
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• 2004.11a
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• pp.401-404
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• 2004

임베디드 시스템의 개발이 시장 적시성과 개발 생산성을 만족시키도록 개발 방법을 향상시키기 위해 제품 계열(Product Line) 기반의 개발 방법을 제시한다. 기존에 생성된 소프트웨어 컴포넌트를 재사용할 수 있는 컴포넌트 기반 시스템 개발 방법론을 제시하고 종합적이고 체계적인 형태의 재사용 프로세스를 구성하며 각 단계별로 필요한 작업과 제품 생산 원칙을 살펴보도록 한다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.5
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• pp.1253-1262
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• 1999

For the efficient co-authoring of multimedia documents in a distributed systems environment, the cooperative-work management systems that can not only allow the sharing of distributed resources but also facilitate the authors' interaction, are needed. In this paper, we present a cooperative-work management system with hybrid architecture, called CW-MAN, in which the information on shared objects and co-authoring management is stored in a dedicated computer system but the shared objects distributed all over the local computer systems. The main management functions provided by the CW-MAN are those for shared objects, session, and telepointing. The shared-object use them exclusively. The session managements allows authors to dynamically create, update, and destroy sessions. Lastly, the telepointing management allows local pointing events to be synchronously presented to remote systems.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.4
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• pp.257-262
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• 2008

This paper studies the operational characteristics of Multi-Phase Interleaved Boost converter operating in Boundary Conduction Mode. The generalized transfer functions of interest are derived from the full-order averaged model approach and then the steady-state and dynamic characteristics are analyzed. The theoretical results are verified through an experimental prototype of the 800W boost PFC converter for 60inch PDP power module.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.5
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• pp.406-414
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• 2009

To cope with the high power density and low cost in switching power supply, LLC resonant converters with the two resonant tank circuits composed of resonance capacitors and two transformers are proposed in this paper. Each transformers used for the proposed resonant circuits are parallel connected in the primary and series connected in the secondary to reduce the current unbalance. The proposed LLC resonant converters are described and verified on 300W experimental prototype.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.847-849
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• 2005

최근 DRAM 특성인 바이트 단위의 빠른 접근과 디스크나 플래시 메모리 특성인 비휘발성을 동시에 제공하는 차세대 비휘발성 메모리가 등장하고 있다. 본 논문에서는 비휘발성 메모리를 위한 새로운 파일시스템을 제안한다. 이 파일시스템은 메모리 본래의 특성대로 기존의 메모리 공간 할당 함수 인터페이스로 접근이 가능하며, 일반 파일시스템 인터페이스로도 접근이 가능하다. 또한 이 파일시스템은 효율적인 공간관리 및 성능 향상을 위하여 가변 크기 블록 사이즈를 지원한다. 한편 루트 파일시스템 용도로 사용 시 부팅 시간의 단축이 가능하며, page table 매핑 수정을 통해 실행 가능 파일의 직접 수행을 제공한다.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1086-1088
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• 1996

A number of recent paper have investigated the feasibility of synchronizing chaotic system. In this paper we proposed the chaotic synchronization of the canonical. Chua's circuit with RLCG transmission line by drive-response system. We expect that proposed method is available to secure communication with RLCG transmission line.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1146-1148
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• 1996

In this paper, uncertain parameters of the heat transfer model of a Dynamically Tuned Gyroscope (DTG) are estimated by the Recursive Least Squares (RLS) method. Also, using this model, a temperature controller for a DTG is designed. As the temperature controller, a PI controller is used. It is presented that a controller can be easily designed when the heat transfer model of a DTG is used. By simulations and experiments, it is shown that the estimated heat transfer model is appropriate and the desired performance of the temperature controller is satisfied.