• 한국콘텐츠학회논문지
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• 제13권4호
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• pp.137-144
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• 2013

스마트기기의 보급이 증가하고 그 종류도 다양해짐에 따라 기존의 여러 가지 기능들이 이 스마트기기에 집중되고 있다. 종이책 시장이 일부 전자책 시장으로 편입되어 가고 있는 것도 이러한 현상 중의 하나이다. 전자책의 수요가 증가 하면서 시장에서 전자책의 형태도 조금씩 발전하는 것을 관찰할 수 있다. 본 논문에서는 스마트기기에 설치되는 어플리케이션 형태인 전자책 뷰어의 인터페이스에 대한 사용성 평가를 실시하였다. 또한, 전자책의 사용성 평가를 위한 항목을 정의하여 사용 패턴을 객관적으로 관찰하고 설문 기법을 사용하였다. 따라서 본 연구는 전자책 인터페이스 사용성의 평가를 분석하여 전자책의 제작 방향과 개선방향을 제시하였다.

• Journal of Electrical Engineering and Technology
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• 제7권5호
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• pp.672-680
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• 2012

This paper proposes the control strategy of the shunt Flexible AC Transmission System (FACTS) devices to improve transient stability in multimachine power system. The multimachine power system has high nonlinear response after severe disturbance. The concept of Lyapunov energy function is applied to derive nonlinear control strategy and it was found that the time derivative of line voltage is not only can apply to control the shunt FACTS devices in multimachine system but also is locally measurable signal. The fuzzy logic control is also applied to overcome the uncertainty of various disturbances in multimachine power system. This paper presents the method of investigating the effect of the shunt FACTS devices on transient stability improvement. The proposed control strategy and the method of simulation are tested on the new England power system. It was found that the shunt FACTS devices based on the proposed nonlinear control strategy can improve transient stability of multimachine power system.

• 한국전기전자재료학회논문지
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• 제31권2호
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• pp.94-97
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• 2018

Lead zirconate titanate/poly-vinylidene fluoride (PZT/PVDF) piezoelectric devices were fabricated by incorporating carbon nanotubes (CNTs), for use as flexible energy harvesting devices. CNTs were added to maximize the formation of the ${\beta}$ phase of PVDF to enhance the piezoelectricity of the devices. The phase transition of PVDF induced by the addition of CNTs was confirmed by analyzing the X-ray diffraction patterns, scanning electron microscopy images, and atomic force microscopy images. The enhanced output efficiency of the PZT/PVDF piezoelectric devices was confirmed by measuring the output current and voltage of the fabricated devices. The maximum output current and voltage of the PZT/PVDF piezoelectric devices was 200 nA and 350 mV, respectively, upon incorporation of 0.06 wt% CNTs.

• 대한의용생체공학회:의공학회지
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• 제39권6호
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• pp.268-277
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• 2018

With drastic change in the market and technology of medical devices, a comparative analysis is necessary in advanced systems internationally in order to prepare domestically applicable plans for improvement in classification and differential grade management for items of medical devices. This research examines and analyzes the differences of definition and legal systems of medical devices among Korea, United States, EU, Japan and China, and investigates classification and grading system of each country to identify disadvantages of classification and grading structures for medical device in Korea. This research suggests ways to supplement the disadvantages of domestic classification and grading system of medical devices, and elicits differential management plans for medical devices.

• 한국도로학회논문집
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• 제10권4호
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• pp.235-245
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• 2008

본 연구에서는 도로의 증가와 더불어 급속히 증가하고 있는 터널에서 차량이 터널에 진입할 때의 속도편차를 분석하여 터널입구부의 안전성을 증진할 수 있는 방안에 대하여 연구하였다. 터널의 존재는 운전자에게 그 자체만으로서 단순한 오르막 경사보다 더 큰 속도 감소를 유발하며, 터널 입구부에서 발생하는 차량 충돌사고는 다른 도로구간에서 발생하는 사고와 비교해 볼 때 피해가 더 크다. 따라서 사고로 인한 피해를 경감시키기 위해 터널 입구부에 PE방호벽이나 가드레일 등의 안전시설을 설치하고 있지만, 운전자에게 이것은 또 다른 장애물로 인식될 수 있다. 터널 입구부에 설치되어 있는 안전시설물의 형태는 크게 PE방호벽, 가드레일, PE 드럼 등이 있으나, 본 연구에서는 고속도로터널 입구에 일반적으로 가장 많이 설치되어 있는PE방호벽과 운전자에게 장애물로 인식될 수 있는 이러한 안전시설물이 설치되어 있지 않은 경우로 크게 구분하였다. 또한 터널 내부로 진입 할 때 갓길을 포함 우측방여유폭의 차이가 큰 경우와 작은 경우로 구분하였다. 4가지 형태의 터널 입구부에서의 차량속도와 일반도로구간에서의 YDS(차량검지체계)로 수집된 속도의 차이를 분석에 사용하였다. 통계적 검증을 통하여 안전시설물 설치 형태와 우측방여유폭의 차이에 따른 각 Case별 유의성을 검토하여 터널 입구부 안전성 증진을 위한 대안을 제시하고자 한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.189-192
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• 2004

To improvement life-time of the organic light emitting diodes(OLEDs). We investigate the inorganic composite film based on MgO and $SiO_2$ to protect from the moisture and oxygen. The inorganic composite films are added the base materials to the co-operate materials using the mixed process and it is deposited on plastic substrate by e-beam evaporator. In order to analyze as kinds of inorganic materials, Water Vapor method of Transmission Rate (WVTR) and Oxygen Transmission Rate (OTR) are measured by Permatran equipment(MOCON Corp.). For comparison. an MgD- and $SiO_2$-based composite film has lower values of WVTR and OTR than inorganic composite/compound films of ones. The results obtained here shows that this film is suitable for passivation layer to extend the life-time of OLEDs.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.178-181
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• 2001

The organic light-emitting devices (OLEDs) based on fluorescence have low efficiencies due to the requirement of spin-symmetry conservation. By using the phosphorescent material, the internal quantum efficiency can reach 100 %, compared to 25 % in the case of the fluorescent material. Thus, the phosphorescent OLEDs have recently been extensively studied and showed higher internal quantum efficiencies then the conventional OLEDs. In this study, we investigated the characteristics of the phosphorescent OLEDs, with the green emitting phosphor, Ir(ppy)$_3$ (tris(2-phenylpyridine)iridium). The devices with a structure of ITO/TPD/Ir(PPy)$_3$ doped in the host material/BCP/Alq$_3$/Li:Al/Al were fabricated, and its electrical and optical characteristics were studied. By changing the doping concentration of Ir(PPy)$_3$ and the host materials, we fabricated several devices and investigated the device characteristics.

• 한국진공학회지
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• 제4권1호
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• pp.60-66
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• 1995

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2003년도 추계학술발표대회 요약집
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• pp.477.2-477.2
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• 2003

• 한국군사과학기술학회지
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• 제12권4호
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• pp.483-490
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• 2009

In this paper, a novel low-damage silicon nitride passivation for 100nm InAlAs/InGaAs MHEMTs has been developed using remote ICPCVD. The silicon nitride deposited by ICPCVD showed higher quality, higher density, and lower hydrogen concentration than those of silicon nitride deposited by PECVD. In particular, we successfully minimized the plasma damage by separating the silicon nitride deposition region remotely from ICP generation region, typically with distance of 34cm. The silicon nitride passivation with remote ICPCVD has been successfully demonstrated on GaAs MHEMTs with minimized damage. The passivated devices showed considerable improvement in DC characteristics and also exhibited excellent RF characteristics($f_T$of 200GHz).The devices with remote ICPCVD passivation of 50nm silicon nitride exhibited 22% improvement(535mS/mm to 654mS/mm) of a maximum extrinsic transconductance($g_{m.max}$) and 20% improvement(551mA/mm to 662mA/mm) of a maximum saturation drain current ($I_{DS.max}$) compared to those of unpassivated ones, respectively. The results achieved in this work demonstrate that remote ICPCVD is a suitable candidate for the next-generation MHEMT passivation technique.