• 문화기술의 융합
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• 제4권3호
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• pp.75-86
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• 2018

데스크톱 다큐멘터리는 카메라로 촬영하는 대신 인터넷 오픈 아카이브에서 검색하고 선택한 멀티미디어 콘텐츠를 재료로 컴퓨터 인터페이스 상에서 그것을 재조합하는 창작자의 멀티태스킹 과정 자체를 스크린 캡쳐 기술을 사용해 녹화하여 완성하는 새로운 다큐멘터리 양식이다. 본 논문에서는 뉴 미디어 환경에서 잠재적 아카이브를 데이터 베이스 내러티브로 전환하고, 영화적 미장센을 컴퓨터 미장인터페이스로 바꾸며, 의식의 흐름을 통한 큐레이션으로서의 창작 메커니즘을 통해 창작과 비평의 경계를 오가는 메타-시네마이자 뉴 미디어 아트의 실험적 시도로서, 주류 호러 영화의 새로운 혼성 장르적 시도로서, 극영화 창작의 새로운 방식으로서, 새로운 모큐멘터리적 시도로서, 그리고 창작과 비평의 경계를 오가는 비디오 에세이와 비평 영화의 새로운 양식으로서 2010년대를 기점으로 부상하고 있는 데스크톱 다큐멘터리의 개념과 유형 및 특성을 연구한다.

• Journal of Welding and Joining
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• 제29권1호
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• pp.99-106
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• 2011

Joint strength between a solder ball and a pad on a substrate is one of the major factors which have effects on electronic device reliability. The effort to improve solder joint strength via surface cleaning, heat treatment and solder composition change have been in progress. This paper will discuss the method of solder ball joint strength improvement using LF hydrogen radical cleaning treatment and focus on the effects of surface treatment condition on the solder ball shear strength and interfacial reactions. In the joint without radical cleaning, voids were observed at the interface. However, the specimens cleaned by hydrogen-radical didn't have voids at the interface regardless of cleaning time. The shear strength between the solder ball and the pad was increased over 120%(about 800gf) when compared to that without the radical treatment (680gf) under the same reflow condition. Especially, at the specimen treated for 5minutes, ball shear strength was considerably increased over 150%(1150gf). Through the observation of fracture surface and cross-section microstructure, the increase of joint strength resulted from the change of fracture mode, that is, from the solder ball fracture to IMC/Ni(P) interfacial fracture. The other cases like radical treated specimen for 1, 3, 7, 9min. showed IMC/solder interfacial fracture rather than fracture in the solder ball.

• Journal of Power Electronics
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• 제16권6호
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• pp.2035-2044
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• 2016

In order to match the voltages between high voltage battery stacks and low voltage super-capacitors with a high conversion efficiency in hybrid energy sources electric vehicles (HESEVs), a high ratio bidirectional DC-DC converter with a synchronous rectification H-Bridge is proposed in this paper. The principles of high ratio step-down and step-up operations are analyzed. In terms of the bidirectional characteristic of the H-Bridge, the bidirectional synchronous rectification (SR) operation is presented without any extra hardware. Then the SR power switches can achieve zero voltage switching (ZVS) turn-on and turn-off during dead time, and the power conversion efficiency is improved compared to that of the diode rectification (DR) operation, as well as the utilization of power switches. Experimental results show that the proposed converter can operate bidirectionally in the wide ratio range of 3~10, when the low voltage continuously varies between 15V and 50V. The maximum efficiencies are 94.1% in the Buck mode, and 93.6% in the Boost mode. In addition, the corresponding largest efficiency variations between SR and DR operations are 4.8% and 3.4%. This converter is suitable for use as a power interface between the battery stacks and super-capacitors in HESEVs.

• 한국통신학회논문지
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• 제33권3B호
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• pp.91-99
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• 2008

본 논문에서는 혼합형 2단 AWG 기반의 WDM-PON에서 기존 802.1D 브리지 기술 규격과 호환 가능하면서 이더넷 LAN 기능을 효율적으로 제공하기 위하여 ULSLE(Upper Layer Shared LAN Emulation) 기능을 설계한다. 제안한 구조에서 ULSLE는 외부 브리지와의 인터페이스를 제공하기 위하여 OLT의 MAC 제어 계층 상위에 존재하며 PON-Tag를 기반으로 에뮬레이션 기능을 수행한다. 이때 PON-Tag는 AWG 기반의 WDM-PON 구조를 고려하여 ONU로부터 전송된 데이터 프레임의 전송 타입과 목적지 판별을 위해서만 사용된다. 이는 하향 프레임 전송에서 PON-Tag를 사용하지 않음으로써 OLT와 ONU에서 PON-Tag 프로세싱 오버헤드와 복잡도를 감소시킨다. 제안한 ULSLE 기능의 검증 및 성능 평가를 위하여 OPNET을 이용하였으며, 검증 시나리오에 따라 각 LLID와 모드 비트에 따른 ULSLE 기능 검증을 수행한다.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.926-936
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• 2017

The nonlinear behavior and the high performance requirement are the main problems that appear in the design of manipulator robots and their controllers. For that reason, the simulation, real-time execution and comparison of the performance of controllers applied to a robot with three degrees of freedom are presented. Five controllers are prepared to test the robot's dynamic model: predictive; hyperbolic sine-cosine; sliding mode; hybrid composed of a predictive + hyperbolic sine-cosine controller; and adaptive controller. A redundant robot, a communication and signal conditioning interface, and a simulator are developed by means of the MatLab/Simulink software, which allows analyzing the dynamic performance of the robot and of the designed controllers. The manipulator robot is made to follow a test trajectory which, thanks to the proposed controllers, it can do. The results of the performance of this manipulator and of its controllers, for each of the three joints, are compared by means of RMS indices, considering joint errors according to the imposed trajectory and to the controller used.

• Journal of Welding and Joining
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• 제34권6호
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• pp.28-34
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• 2016

Galvannealed(GA) steels are now generally used in car body manufacturing for corrosion resistance. In this study, the weldability and joint mechanical behavior of a newly developed 1.2GPa grade GA ultra high strength TRIP(transformation induced plasticity) steel was investigated for three joining processes, such as adhesive bonding, resistance spot welding and weldbonding. Under both shear and peel stress conditions, the failure mode of the adhesive joints were the mixture of the adhesive cohesive failure, adhesive interface failure and coating layer failure. It means that the adhesion strength of GA coating onto the base metal was similar to that of adhesive bonding onto the GA coating. Under the shear stress condition, the weldbonding exerted to expand the optimal spot welding condition of 1.2GPa GA TRIP steel because the strength of adhesive bond overwhelmed that of the resistance spot weld. Under the peel stress condition, the weldbonding also exerted to expand the optimal spot welding condition of 1.2GPa GA TRIP steel by inducing the tear fracture mode rather than the partial plug fracture mode.

• Restorative Dentistry and Endodontics
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• 제28권3호
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• pp.222-231
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• 2003

The purpose of this study was to compare shear bond strength and interfacial pattern of composite bond-ed to dentin using self-etching adhesive systems. Sixty extracted human molars with exposed occlusal dentin were divided into four groups and bonded with four adhesives and composites. Single Bond/Filtek Z 350(SB), Tyrian SPE-One-Step Plus/Aelitefil(TY), Prompt L-Pop/Filtek Z 250(LP), and One-Up Bond F/palfique Toughwell(OU). The results of this study were as follows; 1 Shear bond strength for OU was significantly lower than that of other groups(p＜0.05). No significant difference was founded among SB, TY, and LP. 2. Failure modes to dentin showed adhesive and mixed for SB TY and LP, but them for OU showed adhesive in all spceimens. 3. Dentin-resin interface showed close adaptation for SB, TY, and LP, but it showed gap for OU. 4. The hybrid layers for TY, LP OU were thinner than that of SB. Adhesive layers were observed between composite and hybrid layer, which were 5 $\mu\textrm{m}$ thick for TY and 10 $\mu\textrm{m}$ thick for OU.

• 정보보호학회논문지
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• 제17권6호
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• pp.89-98
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• 2007

최근 인터넷 기술의 급격한 발전으로 정보화 저변 확대라는 긍정적 측면과 함께, 이를 이용한 악의적인 행위들이 지속적으로 일어나고 있어 사회 전 영역에 걸쳐 피해가 속출하고 있다. 특히 악의적인 용도를 위해 제작되는 악성코드의 폐해가 날이 갈수록 급증하고 있고, 또한 개인정보 유출, 해킹, 피싱 등의 응용범죄의 기본수단이 되어가고 있다. 본 논문에서는 이러한 악성코드들을 효과적이고 단계적으로 분석, 탐지할 수 있는 기술에 관하여 기술한다. 본 연구는 악성코드의 은닉도와 악의적 기능 시그너처를 추출함으로서 기존의 악성코드들 뿐 아니라 새로운 악성코드와 변종들에 대해서도 능동적으로 대처할 수 있다.

• 한국결정성장학회지
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• 제24권4호
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• pp.151-157
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• 2014

The degradation mechanisms of thermal barrier coatings (TBCs) were investigated in different thermal fatigue condition in terms of microstructural analyses. The isothermal and cyclic oxidation tests were conducted to atmospheric plasma sprayed-TBCs on NIMONIC 263 substrates. The delamination occurred by the oxide layer formation at the interface, the Ni/Cr-based oxide was formed after Al-based oxide layer grew up to ${\sim}10{\mu}m$ in the isothermal condition. In the cyclic oxidation with dwell time, the failure occurred earlier (500 hr) than in the isothermal oxidation (900 hr) at same temperature. The thickness of Al-based oxide layer of the delaminated specimen in the cyclic condition was ${\sim}4{\mu}m$ and the interfacial cracks were observed. The acoustic emission method revealed that the cracks generated during the cooling step. It was considered that the specimens were prevented from the formation of the Al-based oxide by cooling treatment, and the degradation mode in the cyclic test was dominantly interfacial cracking by the difference of thermal expansion coefficients of the coating layers.

• 한국산학기술학회논문지
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• 제17권8호
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• pp.449-455
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• 2016

본 연구에서는 Eurocode에서 제시하는 콘크리트 부재간 계면조건을 고려한 전단강도 설계식을 압축강도가 서로 다른 부재 연결부에 대해서도 적용할 수 있는지를 검토하기 위하여 전단실험을 수행하고 설계 평가식과 비교하였다. Eurocode에서 제시하는 전단강도 평가식의 변수를 고려하여 콘크리트 압축강도, 전단철근 보강비, 요철계면을 변수로 하는 부재를 제작하였고, 콘크리트층 간의 강도 차이와 요철계면의 유무에 따른 전단강도에 주안점을 두고 전단실험을 수행하였다. 실험을 통해 계측한 실제 전단강도를 Eurocode의 전단강도 평가식을 이용한 계산값과 비교하여 실제 전단강도 수준과 평가식과의 차이를 평가하였으며, 이종강도를 갖는 콘크리트 층에서 압축강도가 증가함에 따라 전단강도도 증가하며, 계면요철을 둔 연결부 전단강도는 설계기준의 평가식으로 계산한 값에 비해 20~50%까지 차이를 보이는 것으로 나타났다. 철근보강비가 작은 경우에는 계면요철에 의한 전단저항력이 전단강도에 주로 기여하며, 이 경우에는 계면에서의 급격한 파괴가 일어나는 현상과 전단강도 편차가 크게 나타남에 따라 평가식과 큰 차이를 보였다. 특히, 이종강도를 갖는 콘크리트 층의 전단강도는 압축강도 차이가 클수록 강도 평가식과 큰 차이를 보이는 것으로 판단된다.