• Journal of the Korean Institute of Educational Facilities
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• v.16 no.5
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• pp.19-26
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• 2009

This study attempts to find out the spatial characteristics of the converging technology laboratory. For this, the understanding of the nature of converging technology and its necessary system requirements are crucial. The foremost concern lies in the 'flexibility' of the laboratory space, i.e. 'open-lab system', because of the multi-disciplinary spatial arrangement which is supposed to be open to a number of different research fields in the same building cluster. From the case analysis, this study reveals that in order to maximize the adjustability, the module based space unit plan should be considered at the earliest stage. In addition, it is also found from the analysis that the linkage of the communication spaces such as seminar room, auditorium, lounge, rest room, dining room, and corridors should be dealt with a higher degree of sophistication, since these facilitate the interaction of information at the behavioral level.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.9
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• pp.1910-1917
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• 2011

In this paper, a cloud computing platform is designed and implemented based on an open source cloud platform, OpenNebula, and Xen hypervisor on each node for efficient computer lab system. For the purpose of convenient management, a web-based user interface has been developed for the cloud virtualization system. Once individual virtual machine is allocated to a user based upon class schedule, each user can access the virtual machine remotely and use appropriate operating system and application programs. The developed system can reduce computer lab upgrade cost, management cost, and administration time considerably.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.522-524
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• 2016

E-Navigation is required port operation for effective and safety. Maritime traffic data must be exchanged between Vessel Traffic Service Center and ship for e-navigation build. In this paper, We designed Open API system for the exchange and use of maritime traffic data. This system provide Open API data to $3^{rd}$ party.

• Journal of Electrical Engineering and Technology
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• v.10 no.6
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• pp.2277-2287
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• 2015

In recent times, multilevel inverters are given high priority in many large industrial drive applications. However, the reliability of multilevel inverters are mainly affected by the failure of power electronic switches. In this paper, open-switch and short-switch failure of multilevel inverters and its identification using a high performance diagnostic system is discussed. Experimental and simulation studies were carried out on five level cascaded H-Bridge multilevel inverter and its output voltage waveforms were analyzed at different switch fault cases and at different modulation index values. Salient frequency domain features of the output voltage signal were extracted using the discrete wavelet transform multi resolution signal decomposition technique. Real time application of the proposed fault diagnostic system was implemented through the LabVIEW software. Artificial neural network was trained offline using the Matlab software and the resultant network parameters were transferred to LabVIEW real time system. In the proposed system, it is possible to precisely identify the individual faulty switch (may be due to open-switch (or) short-switch failure) of multilevel inverters.

• Journal of Communications and Networks
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• v.4 no.4
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• pp.336-343
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• 2002

A major challenge for next generation mobile communication is capturing the system architecture’s complexity with all its internal and external dependencies. Seamless integration of heterogeneous environments in all system parts is a key requirement. Moreover, future systems have to consider the different evolution cycles of individual system parts. Among those, services are expected to change the fastest. With respect to these considerations, we propose an overall architecture for next generation mobile communication systems. It covers all system parts from wireless transmission to applications including network and middleware platform. Our approach focuses on adaptability in terms of recon- figurability and programmability to support unanticipated system evolution. Therefore, we consider abstraction layers which consist of adaptable cooperating components grouped by open platforms rather than rigid system layers. In addition to that, we introduce cross-layer cooperation allowing an efficient use of the available resources. Specific scenarios illustrate the feasibility of our approach.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1373-1376
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• 2009

인터넷의 확산과 웹 2.0 서비스의 등장은 기존 서비스 제공자 중심의 ID 관리를 사용자 중심의 ID 관리 형태로 변화시키는 계기가 되었다. 그러나 기존 사용자 중심 ID 관리 기법은 사용자 인증 및 정보 관리에 대한 문제가 존재한다. 본 논문에서는 서비스 제공자가 필요로 하는 정보만을 사용자가 선별적으로 선택하여 제공함으로서 기존 ID 관리 기법의 문제를 해결할 수 있는 사용자 중심의 ID 관리 기법을 이용한 OpenID 시스템을 제안한다. 또한, 실험 및 비교분석을 통하여 보안성 및 효율성 측면에서 우수함을 확인 할 수 있었다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.2
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• pp.254-259
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• 2015

On January 30, 2012 an auxiliary component of Byron Unit 2 was tripped on bus under voltage. The cause of the event was the failure of the C-phase insulator track for the Unit 2 station auxiliary transformer(SAT) revenue metering transformer. In addition to this event, other events have occurred at other plants resulting in an open-phase condition.[1] Therefore, Nuclear Regulatory Commission(NRC) has requested that not only nuclear power plant(NPP) operating company but also its Design Certification(DC) applicant have to prepare open-phase detecting system in their operating plants and design document. In this paper, various open-phase conditions are simulated in NPP using Electromagnetic Transient Program(EMTP) and Atpdraw, and open-phase condition detecting system is proposed for Main Transformer(MT), Unit Auxiliary Transformer(UAT) and SAT connected power line in NPP.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.351-354
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• 2012

The core of cloud computing is to provide efficient computing resource sharing. In this paper, we have designed and implemented a virtual computer lab system using open source cloud computing infrastructure. The proposed virtual computer lab system can be used to reduce computer upgrade and maintenance cost significantly.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.15-17
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• 1996

In this paper, a modified microstep drive of PM step motor is presented. The open-loop drive of a step motor is attractive and widely accepted in applications of speed and position controls. However, the performance of the step motor is limited under the open-loop drive. The closed-loop control is advantages over the open-loop control not only in that step failure never occurs but that the motion is much quicker and smoother. However, a high resolution sensor is needed for detecting position and speed. The modified microstep drive is constructed as a microstep drive with speed feedback. The advantages of the proposed method is that the controller can be designed by a low resolution sensor and is simpler than other closed-loop controller. A concept of vector control is used for verifying the proposed scheme. Simulations show the performance of the proposed method and a comparison with a classic drive method.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.394-396
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• 2007

Radio occultation (RO) technique has been used in planetary science since 1960s. When signal goes through atmosphere, it is refracted due to the gradient of atmospheric refractivity. In 1995, the first low earth orbit (LEO) satellite, MicroLab-1, was launched to conduct RO mission. It receives the signal from global positioning system (GPS) satellites. After MicroLab-1, other RO missions, such as CHAMP, SAC-C, and GRACE, are executed in several years later. In 2006, Taiwan launched six LEO satellites for RO mission. The mission name is Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC). Under some abnormal situations, multipath and strong fluctuation in phase and amplitude of the signal appear in moist troposphere. Therefore, open loop (OL) technique has been applied to replace traditional phase lock loop (PLL) technique. In this paper, we will summarize the retrieval processing procedure and discuss the advantages and disadvantages of OL technique.