• Ceramist
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• v.21 no.1
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• pp.24-43
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• 2018

Organic-inorganic halide perovskite materials have attracted significant attention during the last few years because of their superior properties for electronic and optoelectronic devices, such as their long charge carrier diffusion lengths and high photoluminescence quantum yields of up to 100% with tunable bandgaps over the entire visible spectral range. In addition to solar cells, light emitting diodes (LEDs) represent a fascinating application for halide perovskite materials. In this study, we review the recent progress in halide perovskite LEDs. The current strategies for improving the performance of halide LEDs, focusing on morphological engineering, dimensional engineering, compositional engineering, surface passivation, interfacial engineering, and the plasmonic effect are discussed. The challenges and perspectives for the future development of halide perovskite LEDs are also considered.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.884-890
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• 2012

Hysteretic behavior model of soft magnetic material usually used in electrical machines and electronic devices is necessary for numerical solution of Maxwell equation. In this study, a new dynamic hysteresis model is presented, based on the nonlinear dynamic system identification from measured data capabilities of fuzzy clustering algorithm. The developed model is based on a Gustafson-Kessel (GK) fuzzy approach used on a normalized gathered data from measured dynamic cycles on a C core transformer made of 0.33mm laminations of cold rolled SiFe. The number of fuzzy rules is optimized by some cluster validity measures like 'partition coefficient' and 'classification entropy'. The clustering results from the GK approach show that it is not only very accurate but also provides its effectiveness and potential for dynamic magnetic hysteresis modeling.

• IE interfaces
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• v.12 no.2
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• pp.274-284
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• 1999

This study is aimed at examining the relationship among the advanced manufacturing technology(AMT) types adopted in Korea, necessary strategic management activities for the selected AMT types and the performance of the AMT introduced. In order to identify such relationship, multivariate analyses are used based on the survey data collected from industry types such as metal processing and assembly, automobile parts, automobile assembly. electric and electronic devices. The study results indicate the following: (1) companies using CIM or ERP tend to be more prepared in terms of human resources; (2) companies adopted CIM and MRPII tend to demonstrate higher performance in terms of both organizational effectiveness and operational efficiency; (3) companies which adopted JIT or ERP perform better in terms of operational efficiency.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.412-418
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• 2004

In this paper, a new distributed intelligent control module based on LonWorks fieldbus for air handling unit(AHU) of heating, ventilating and air-conditioning(HVAC) is proposed to replace with a conventional direct digital control(DDC) with 32 bit microprocessor. This article also addresses an Internet-based HVAC system architecture that combines Web technology and networking. The proposed control architecture has a excellent features such as highly compact and flexible function design, a low priced smart front-end and reliable performance with various functions. This also addresses issues in control network configuration, logical design of field devices by S/W tool, Internet networking and electronic element installation. Experimental results showing the system performance are also included in this paper.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.10
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• pp.35-43
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• 2012

In this paper, a development of agent-based IEDs(Intelligent electronic devices) for integration control of building microgrid in smart green building are proposed. To manage and control this complex energy system of smart green buildings, multi-agent system based networks is needed. Thus, several IEDs for utilizing multi-agent system are developed and modified for the their verification of performance as agent modules functions in the integrated experimental equipment. The good performance of these IED agents are verified from experimental results obtained from seamless bi-directional communication by SOAP/XML protocol between PC agent and IED agent.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.3
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• pp.114-121
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• 2004

Switched reluctance motors have received much attention as a driving means for various industrial applications because they have simple construction, low cost and high efficiency. Nevertheless, the requirements of drive converters make it difficult to lower the overall system cost as compared with the DC motor application. Single phase switched reluctance motors (SPSRMs) provide a solution to the high cost problem since the number of switching power devices can be reduced and consequently the trials for application are increased. However, research involving SPSRMs, especially in the area of design work, is insufficient. This paper introduces a novel design methodology of single phase SRM. The design work for SPSRM comprises the determination of many variables such as stator and rotor pole arc as well as on, off and so on. Managing all variable combinations leads to lengthy computation time and a fault in the design process. For that reason, a reliable technique and brief procedure term are required in SPSRM design.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.98-101
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• 2002

The switching-mode power converter has been widely used because of its features of high efficiency and small weight and size. These features are brought by the ON-OFF operation of semiconductor switching devices. However, this switching operation causes the surge and EMI(Electromagnetic Interference) which deteriorate the reliability of the converter themselves and entire electronic systems. This problem on the surge and noise is one of the most serious difficulties in AC-to-DC converter. In the case of carrier frequency selection, output-voltage of steady state and transient state is fully regulated. A RPWM control method was proposed in order to smooth the switching noise spectrum and reduce it's level. Experimental results are verified by converter operating at 300V/1kW with 5%${\sim}$30% white noise input. Spectrum analysis is performed on the Phase current and the CM noise voltage. The former is measured with Current Probe and the latter is achieved with USN. which are connected to the spectrum analyzer respectively.

• Annual Conference of KIPS
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• 2006.11a
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• pp.547-550
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• 2006

오늘날 의료기기는 내장된 소프트웨어에 의해 제어되는 전자 의료기기의 형태로 급격하게 발전하고 있다. 따라서 전자 의료기기의 품질은 내장된 의료용 소프트웨어의 품질에 의해 크게 좌우될 수 밖에 없다. 특히, 의료기기가 인간의 생명과 밀접하게 연관되어 있다는 점을 고려할 때, 프로그램 가능한 전자 의료기기의 품질 측면에서도 신뢰성 측면을 특히 고려한 평가 방법이 연구되어야 할 것으로 생각된다. 본 연구에서는 소프트웨어 제품평가에 관련된 국제표준인 ISO/IEC 9126과 ISO/IEC 12119를 기반으로 하여 국내의 프로그램 가능한 전자 의료기기의 특성을 고려하여 신뢰성에 대한 평가를 위한 방법을 구축하고자 한다.

• Annual Conference of KIPS
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• 2006.11a
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• pp.535-538
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• 2006

FMEA(Failure Mode & Effect Analysis)는 발생 가능한 잠재 고장의 형태와 그 영향을 평가하고 고장을 예방할 수 있도록 표를 이용하여 체계적으로 접근하는 방법이다. FMEA를 활용하여 전자 의료기기의 신뢰성을 평가할 수 있는 방안에 대한 연구를 통해 의료기기의 신뢰성 향상을 위한 체계적인 접근이 요구된다. 본 연구에서는 소프트웨어의 신뢰성을 평가하기 위한 체계를 구축하기 위해 FMEA 기법을 근간으로 하여 전자 의료기기의 신뢰성 평가 체계 구축에 적용할 수 있는 방안을 수립하고자 한다.

• Journal of Power Electronics
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• v.12 no.6
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• pp.878-885
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• 2012

A new sustainer with primary-side integration of DC/DC converters and energy recovery(SPIDER) circuits is proposed. The proposed circuit operates as a DC-DC converter during address period and energy recovery circuit during sustain period. Therefore, the conventional three electronic circuits composed of the power supply, X-driver, and Y-driver can be reduced to one circuit. As a result, it has desirable advantages such as a simple structure, less mass, fewer devices and cost reduction. Moreover, since the Zero Voltage Switching (ZVS) of all power switches can be guaranteed, a switching loss can be considerably decreased. To confirm the operation, validity, and features of the proposed circuit, experimental results from a prototype for 42-inch PDP are presented.