• Journal of The Korean Association of Information Education
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• v.6 no.3
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• pp.288-297
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• 2002

The paradigm of education has changed with the progress of the information and communication technology. In school, there has been developing and animately discussing many data and ways of using web-practicality for teaching and learning. On the other hand, relatively, there are negligent faces about web-practicality for extension of emotion and will of our children. The common points of pre-studies about the increase of self-concept show that it is difficult to join all of the information because the work is off-line, therefore limiting it's advance so that the program is improved. This study has designed and embodied the system of web based self-expression training program. The result of application of this system has showed the positive effect on formation of self-concept of Cheongju elementary school students.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.694-696
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• 2011

The high enthalpy plasma research center in Chonbuk national university is under construction for four types of plasma equipments. The equipments are 1set of 0.4 MW class enhanced Huels type plasma equipment, 1 set of 2.4 MW class enhanced Huels type plasma quipment, 1 set of 60 kW RF plasma equipment and 1 set of 200 kW RF plasma equipment. 60kW RF plasma system is R&D and pilot scale production equipment of nano powder synthesis and plasma spray coating. 200kW RF plasma system is mass production equipment with high power capacity of nano powder synthesis. 0.4MW plasma system can be applied to the ground test facility for material testing under re-entry conditions for space vehicles.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.05a
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• pp.37-40
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• 2003

We introduce the category IRel (H) consisting of intuitionistic fuzzy relational spaces on sets and we study structures of the category IRel (H) in the viewpoint of the topological universe introduced by L.D.Nel. Thus we show that IRel (H) satisfies all the conditions of a topological universe over Set except the terminal separator property and IRel (H) is cartesian closed over Set.

• Journal of Digital Convergence
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• v.10 no.6
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• pp.253-258
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• 2012

In this thesis, I categorize expression of context data required for context data inference according to five Ws and one H(5W1H) in Ubiquitous computing environment and infer superordinate context by combining context data of 4W1H with inferred context of why. This thesis suggests that we categorize specific context and service according to 6W2H added Whom(specific data or service) and How much (accuracy), and determine proper services for specific contexts by introducing the concept of rough set for expression and inference of categorized contexts and inaccurate knowledge. Since there is an limitation of the set of 0 and 1 when concerned with accuracy of services, I introduce the concept of fuzzy set. To provide users with the most appropriate service by ridding of unnecessary properties through the process of reduction, I also use the concept of rough set.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.515-516
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• 2006

본 논문은 풍속이 변화하는 상황에서 풍력 발전 시스템의 동작을 실시간으로 모의할 수 있는 시뮬레이터의 구성과 실험 결과를 제시한다. 본 논문에서 제시하고자하는 풍력 발전 시스템 시뮬레이터는 실시간 시뮬레이터인 RTDS(Real Time Digital Simulator)와 11kW의 AC 서보 시스템을 포함하는 전동기-발전기 실험 장치(MG set, Motor-Generator Set)로 구현되었다. RTDS는 풍속 모델과 블레이드, 터빈, 발전기를 포함하는 풍력발전 시스템 모델을 실시간으로 모의하며 MG-set은 실시간으로 모의된 풍력 발전 시스템의 물리적 상태를 구현한다. 풍력 발전 시스템 모델의 동작점 궤적과 최대출력점추종(Maximum Power Point Tracking)제어에 의한 풍력 발전 시스템 시뮬레이터의 운전 결과의 제시를 통해 시뮬레이터의 유용성을 검증하였다. 본 논문에서 제시된 시뮬레이터는 상용 실시간 시뮬레이터를 이용하여 간단한 소프트웨어의 수정을 통해 다양한 모델의 풍력 반전 시스템을 모의할 수 있으며 다양한 실험 조건에서 과도상태 및 정상상태 특성 실험이 가능하므로 풍력 발전 시스템의 발전기 특성 평가, 전력 변환 장치의 성능 시험 등에 활용이 가능하다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.985-986
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• 2008

• Journal of Korean Society of Industrial and Systems Engineering
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• v.14 no.24
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• pp.111-121
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• 1991

This paper considers a non preemtive single processor scheduling problem in which each set have the two common due dates. The objective of the problem is to minimize the weighted mean absolute deviation of job completion times about such two common due dates under the assumption that each job has a different weight. Such a job sequence is an W-shaped sequence. We propose three heuristic solution methods based on several dominance conditions. Numerical examples are presented. The performance comparison is made among three heuristic scheduling procedures.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.28.5-28
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• 2001

This paper investigates a classification method of the electrocardiogram (ECG) into different disease categories. The features for the classification of the ECG are the coefficients of the discrete wavelet transform (DWT) of ECG signals. The coefficients are calculated with Haar wavelet, and after DWT we can get 64 coefficients. Each coefficient has morphological information and they may be good features when conventional time-domain features are not available. Since all of them are not meaningful, it is needed to reduce the size of meaningful coefficients set. The distributions of each coefficient can be the rules to classify ECG signal. The optimally reduced feature set is obtained by fuzzy c-means algorithm and rough set theory. First, the each coefficient is clustered by fuzzy c-means algorithm and the clustered ...

• Journal of the Korea Convergence Society
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• v.10 no.11
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• pp.41-46
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• 2019

Recently, the Byzantine Fault Tolerance(BFT) family of consensus algorithms has been attracting attention as the problems of the Proof-of-work (PoW) blockchain consensus algorithms result in energy waste and lack of scalability. One of the great features of the PBFT family consensus algorithms is the formation of a set of validators and consensus within them. In this paper, we compared and analyzed the scalability, targeted attackability, and civil attackability of Algorand, Stellar, and EOS validator set formation methods among BFT family consensus algorithms. Also, we found the problems of each verifier formation method through data analysis, and the consensus algorithms showed that the centralization phenomenon that the few powerful nodes dominate the whole system in common.

• The KIPS Transactions:PartD
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• v.18D no.3
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• pp.197-204
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• 2011

Set-top Box which receives broadcasting signal and delivers it to display device such as TV usually doesn't have low-power mode, standby power mode. On the other side, most consumer electronics support standby power mode. The main reasons come from technical barriers and operational stability. Set-top box normally consumes 80~90% power of active mode even though turning off. This is much higher compared to other consumer electronics which consume less than 1W in standby power mode. However, most developed countries including Korea are enforcing the regulations which enhance energy efficiency of set-top box. This paper describes design and development of low-power set-top box. Key technologies are SoC supporting low-power mode, system hardware and software operating in separated power mode, and middleware managing the power with broadcasting system. Finally, we show energy saving expectation through development and proliferation.