• 대한수학회보
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• 제52권2호
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• pp.549-556
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• 2015

In this paper, we characterize w-Noetherian modules in terms of polynomial modules and w-Nagata modules. Then it is shown that for a finite type w-module M, every w-epimorphism of M onto itself is an isomorphism. We also define and study the concepts of w-Artinian modules and w-simple modules. By using these concepts, it is shown that for a w-Artinian module M, every w-monomorphism of M onto itself is an isomorphism and that for a w-simple module M, $End_RM$ is a division ring.

• 대한수학회보
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• 제56권6호
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• pp.1617-1642
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• 2019

In this paper, we study a theory for the structure of ${\tau}_w$-Loewy series of modules over commutative rings, where ${\tau}_w$ is the hereditary torsion theory induced by the so-called w-operation, and explore the relationship between ${\tau}_w$-Loewy modules and w-Artinian modules.

• Journal of Power Electronics
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• 제13권4호
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• pp.584-591
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• 2013

In this paper, a hybrid booster power module with Si IGBT and Silicon Carbide (SiC) Schottky Barrier Diode (SBDs) is presented. The switching characteristics of the hybrid booster module are compared with commercial Silicon IGBT/Si PIN diode based modules. We applied the booster power module into a non-isolated on board vehicle charger with a simple buck-booster topology. The performances of the on-vehicle charger are analyzed and measured with different power modules. The test data is measured in the same system, at the same points of operation, using the conventional Si and hybrid Si/SiC power modules. The measured power conversion efficiency of the proposed on-vehicle charger is 96.4 % with the SiC SBD based hybrid booster module. The conversion efficiency gain of 1.4 % is realizable by replacing the Si-based booster module with the Si IGBT/SiC SBD hybrid boost module in the 6.6 kW on-vehicle chargers.

• 한국광학회지
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• 제11권3호
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• pp.206-209
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• 2000

DWDM 시스템에서 외부광변조기와 함께 중장거리 전송을 위한 광원으로 사용이 가능한 파장안정화 고출력 CW DFB 레리저 모듈을 셀계 및 제작하였다. 얇은 두께의 soild etalon과 PD array를 사용하여 단순하고 compact한 파장모니터 기능을 광원 모듈에 내장함으로써 DFB LD의 파장 변화를 감지 및 제어 할 수 있도록 하였다. 또한 높은 출력 특성을 가진 DFB LD와 43% 이상의 높은 광결합 효율을 가지는 모듈을 가지는 모듈의 광학적 설계 및 packaging 기술을 활용하여 mA의 CW 전류인가 조건에서 13nW의 고출력특성ㅇ르 가지는 모듈을 제작하여 그 특성을 분석하였다.

• 대한수학회지
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• 제50권5호
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• pp.1051-1066
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• 2013

By utilizing known characterizations of ${\omega}$-Noetherian rings in terms of injective modules, we give more characterizations of ${\omega}$-Noetherian rings. More precisely, we show that a commutative ring R is ${\omega}$-Noetherian if and only if the direct limit of GV -torsion-free injective R-modules is injective; if and only if every R-module has a GV -torsion-free injective (pre)cover; if and only if the direct sum of injective envelopes of ${\omega}$-simple R-modules is injective; if and only if the essential extension of the direct sum of GV -torsion-free injective R-modules is the direct sum of GV -torsion-free injective R-modules; if and only if every $\mathfrak{F}_{w,f}(R)$-injective ${\omega}$-module is injective; if and only if every GV-torsion-free R-module admits an $i$-decomposition.

• 한국정보통신학회논문지
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• 제12권4호
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• pp.636-642
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• 2008

초고속 인터넷의 보급, 디지털 정보장비의 확산 및 생활 패턴의 변화에 따라 흠 네트워크의 필요성이 점차 확대되고 있다. 이에 따라 본 논문에서는 홈 네트워크화를 위해서 8051 MCU, 하드와이어드 TCP/IP(W3150A)를 이용하여 임베디드 이더넷 모듈을 설계, 구현하였다. 타겟 머신에 간단한 웹 서버를 구축하고 이를 이용한 원격제어 프로그램을 포팅하여 원격지에서도 인터넷으로 가전기기를 제어할 수 있도록 하였다. 개발한 모듈을 이용하여 유비쿼터스 시대에 저가격으로 홈 오토메이션을 구현할 수 있으리라 생각한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.272-277
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• 2003

This paper reports the fluid flow and heat transfer around a module cooled by forced air flow generated by a piezoelectric(PZT) cooling fan. A flexible PZT fan with distortion in a fluid transport system of comparatively simple structure which was mounted on a PCB in a parallel-plate channel($450{\times}80{\times}700mm^3$) accelerates surrounding fluid locally. Input voltages of 20-100V and a resonance frequency of 23Hz were used to vibrate the cooling fan. Input power to the module was 4W. The cooling effect using a PZT fan was larger than that of free convection. Fluid flow around the module were visualized by using PIV system. The temperature distribution around heated module were visualized by using liquid crystal film(LCF). We found that the flow type was y-shaped and the cooling effect was increased by the wake generated by a piezoelectric cooling fan.

• 조명전기설비학회논문지
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• 제24권12호
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• pp.38-46
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• 2010

For the development of 100[W] stage lighting, quantitative and uniform color mixing that applied through color adopted Simple-Inverse matching so that color mixing can be possible along Black Body Locus. R,G,B(Red, Green, Blue) LED(Light Emitting Diode) arrangement through LED package character analysis, LED module, and the characteristic of device were considered for uniform color mixing. A distance changeable optical device was built to assure high uniformity and high diffusion of not only the middle of diffusion side but also the border side. Also, we developed the control power circuit that can expand up to 6 channels which are possible for quantitative color mixing, and the high uniformity and high quantified border light for color mixing control and the verification of color mixing characteristics by composing GUI(Graphical user interface) including color mixing simulator. By presenting the experimental results of light color control, we proved the usefulness of our developed border light and the proposed color mixing method.

• Current Optics and Photonics
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• 제1권5호
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• pp.468-473
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• 2017

We determined the feasibility of a fishing camera system using an optical fiber as the fishing line by testing a power-over-fiber (POF) module and multimode optical fiber. Operation of the remote camera module (RCM) without the battery was preferred because the removal of the charging or battery replacement section enabled a waterproof single-body type design. The average efficiency of the photovoltaic power converter (PPC) in the tested POF module was 32.6% at 820 nm, and thus, a high-power laser of at least 1.27 W was required for operating the developed RCM with an electrical dissipation of 413 mW. Because the optical fiber was wound on a fishing reel, composite loss composed of bending and tensile loss occurred. To mitigate the composite loss, we employed a simple holder that showed an improvement in the composite loss of 0.38 dB to 0.8 dB, which was considerably better than the losses without the holder.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 추계학술대회 논문집
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• pp.31-33
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• 2007

In this paper, a simple digital control scheme for the single/parallel module buck converters is proposed using a digital state feedback control method. The discrete state feedback controller structure for the robust tracking control is derived by using the error state. The proposed control system can precisely achieve the interleaved current sharing and the output regulation, and can achieve the systematical controller design for a given converter specification using the pole placement technique. For a design example, the single module buck converter is simulated using the MATLAB Simulink software and two 100W parallel module buck converters with a TMS320F2812 DSP is implemented.