• Proceedings of the Korea Information Processing Society Conference
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• 2003.05a
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• pp.519-522
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• 2003

본 논문에서는 순차주사 CCD 이미지 센서를 위한 채널내 상관관계를 이용한 가변 칼라비율을 가진 칼라 보간법을 제안했다. 제안된 가변 칼라 비율은 채널내 상관관계뿐만 아니라 채널간의 상관관계를 이용하며 경계부근과 복잡한 국소지점에 나타난 왜곡된 칼라를 제거했다 채널간 상관관계를 이용한 가변 칼라비율을 가진 칼라 보간법은 기존의 접근 방법에 비해 주관적 그리고 객관적인 화질로 모두 우수한 결과를 실험적으로 보였다.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.71-72
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• 2016

전동기의 운전 영역을 확대하기 위해 부스트 컨버터를 이용하여 가변 DC link를 합성한다. 가변 DC link 구간에서는 스위칭 손실이 증가하기 때문에 스위칭 횟수를 줄이는 전략이 필요하다. 제안하는 Edge-Cutting Pulse Width Modulation(ECPWM)을 통해 스위칭 손실을 1/3로 절감하고, 최적의 고조파 특성을 갖는 직류단 전압의 크기를 결정한다. 이를 이용해 가변 직류단 전압 구간에서 인버터 손실을 감소시키며, Bolognani 과변조 방법을 적용해 안정적인 6-스텝으로의 절환까지 고려한다.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.22-23
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• 2003

광섬유 가변 감쇠기는 광증폭기, add／drop 모듈, Mux／Demux, 광송수신기 등 중요한 광통신 시스템의 입력 및 출력 광신호 레벨을 적절하게 제어하기 위해 요구되는 중요한 소자이다. 가변 감쇠기는 높은 신뢰성, 높은 해상도, 작은 삽입손실, 낮은 편광 및 파장 의존성 손실 등이 요구되어 진다. 가변 광감쇠기는 평면 기판에 형성된 도파로 의 열광학 효과나 전기광학 효과를 이용하는 기법과 MEMS 기술에 기초한 방법이 잘 알려져 있다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.86-87
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• 2003

단일 소자로 외부의 제어회로를 통해 여러 파장으로 발진파장을 제어할 수 있는 파장가변 레이저 다이오드는 고정된 파장으로 발진하는 레이저 다이오드에 비해 여러 경제적 이점을 가지며 보다 유연한 광 네트워크의 구성이 가능하게 한다. 이러한 이유로 현재까지 다양한 구조의 파장가변 레이저 다이오드가 제안되고 개발되어 왔다. 본 논문에서는 새로운 구조의 광대역 파장가변 레이저 다이오드를 제안하였다. (중략)

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.354-355
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• 2019

본 논문은 Polymer Dispersed Liquid Crystal(PDLC)의 구형파 구동방식에 따른 전기광학적 특성을 비교한다. 현재 PDLC는 변압기를 사용하여 전압가변이 힘들어 ON/OFF 기능으로만 사용한다. PDLC 구동시스템에 전력변환장치를 적용하면 전압가변이 용이하여 PDLC의 투과도 조절이 가능하다. 구형파 구동방식 중 인버터의 DC Link Voltage를 가변하는 방식과 Duty ratio를 가변하는 두 방식의 전기광학적 특성을 비교하였다. 이를 실험을 통하여 전기광학적 특성을 분석하였다.

• International Journal of Highway Engineering
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• v.13 no.3
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• pp.185-193
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• 2011

As a Lift axle is an additional axle installed mostly in heavy freight truck, It"s introduced for the purpose of cost saving, such as logistics, fuel, tire wear and prevention of the pavement damage. However, the Effects of a lift axle are anecdotal and they have occurred often that a lift axle is used improperly by expectations of some drivers. For these reasons, this study conducts a field experiment in order to identifying the change rate of fuel consumption due to an a Lift axle using, develops the fuel consumption model of field data, and then compares the effects of a Lift axle using through application of the model. As a result, fuel consumption decreased in loading conditions that are both empty and full when not using a lift axle.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.1
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• pp.16-26
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• 2011

Variable speed limit(VSL) is one of the highway ITS techniques designed to prevent accidents and traffic slow down by reducing congestion or speed variation between vehicles and lanes prior to arrive at the accident location by limiting speed. In Korea, while people have recognized the need for variable speed limit beginning with Seoul's urban expressway and installed facilities in order to provide guide for speed limit per lane and lane use, there has not been enough development of algorithm for internal administration as well as research on the basic principles behind administering variable speed limit. This study is for modeling and evaluating the VSL strategies based on the traffic flow theory. Supply-Demand method of the Cell Transmission Model is applied to demonstrate the traffic features and shockwaves to upstream of the bottleneck with/without VSL. We verified the explanation of Cell Transmission Model for the numerical example. and as the result, it is found that VSL strategies can reduce the total travel time in the congested section and variation of the speed. It means VSL is useful to improve the traffic condition and the safety on highway

• The KIPS Transactions:PartC
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• v.9C no.3
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• pp.399-406
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• 2002

We consider design of multiservice network link, in which connections of constant- and adaptive-rate services arrive and leave dynamically. We propose performance analysis and design methods of these dynamic multiservice networks. A multiservice network link is modeled by a Markov chain, and data rates for adaptive-rate connections are derived using QBD (Quasi-Birth-Death) processes and matrix-geometric equations. We estimate average number of adaptive-rate connections, average data rate and average connection delay. The performance of constant-rate connections is determined from the blocking probability of the connections. Based on the performance of constant-and adaptive- rate connections, we propose a design methods of a network link to satisfy performance requirements of constant- and adaptive-rate connections (data rates, delay, blocking probability). Our methods can be used for the analysis and design of network switch supporting dynamic data and voice (video) traffic simultaneously.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.3
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• pp.311-320
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• 2008

In this paper, a new variable active inductor using a conventional grounded active inductor with feedback variable LC-resonator is proposed. The grounded active inductor is realized by the gyrator-C topology and the variable LC-resonator is realized by the low-Q spiral inductor and varactor. This variable LC-resonator can compensate the degradation of Q-factor due to parasitic capacitance of a transistor, and the frequency range with high Q-factor is adjustable by resonance frequency adjustment of LC-resonator. The fabricated variable active inductor with Magnachip $0.18{\mu}m$ CMOS process shows that high-Q frequency range can be adjusted according to varactor control voltage from 4.66 GHz to 5.45 GHz and Q-factor is higher than 50 in the operating frequency ranges. The measured inductance at 4.9GHz can be controlled from 4.12 nH to 5.97 nH by control voltage.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1170-1174
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• 2014

If cavitation occurs in propeller, it generates vibration and noise accordingly which results in low efficiency of propeller. It's important to increase cavitation inception speed(CIS) since the noise of cavitation increases significantly from the beginning of cavitation. This paper describes the result of actual observation and measurement onboard ship with controllable pitch propeller(CPP), so as to verify the first occurrence phenomenon of cavitation. The research suggests new type of controllable pitch propeller with improved CIS at the bolt as it started with bolt cavitation as result of observation. It's not found bolt cavitation on the CPP proposed in this paper, furthermore its CIS is increased approximately by 4.5 knots than the existing CPP. The result of the research can be used for development of low-noise CPP and improving performance of CIS.