• 한국광학회지
• /
• 제17권3호
• /
• pp.290-295
• /
• 2006

전기전도도가 높은 구리선 도파로에 THz 전자기파의 결합은 THz 유선방식의 전파에 있어 테라파의 크기 및 주파수 특성을 결정짓는 중요한 요인 중의 하나이다. 본 연구에서는 직경 $480{\mu}m$, 길이 23 cm의 구리선 도파로에 테라파를 전파시켜 1 THz 주파수 범위를 가진 THz 펄스를 측정하였다. 도파로와 transmitter chip 또는 receiver chip 사이의 공극 간격을 최대 $275{\mu}m$까지 확대하여 송신부와 수신부의 결합 특성을 접촉상태와 비교 분석하였다. 실험결과 송신부의 결합민감도가 수신부보다 약 3배 이상 높게 나타났으며 수신부에서 도파로와 receiver사이의 공극을 통하여 테라파가 공기 중으로 전파됨을 알 수 있었다. 또한 구리선 도파로에 pin hole를 위치시켜 pin hole의 직경에 따른 테라파의 변화를 연구하였으며 대부분의 THz field는 구리선 표면에 분포됨을 확인할 수 있었다.

• 한국정보통신학회논문지
• /
• 제6권2호
• /
• pp.236-247
• /
• 2002

ATM망에서 큐 서비스 방식에서는 상위 프레임과 하위 프레임을 따로 정의하여 대역폭 할당과 전송 지연 보장을 분리할 수 있기 때문에 종단간 전송한계에서 QoS를 보장 할 수 있는 단순화한 큐 서비스 구현을 제안하였다. 제안한 큐 서비스 방식은 실시간 트래픽과 비실시간 트래픽을 나누어 저장하기 때문 에 연결별 트래픽 조절기 없이도 지연 지터 특성이 개선되었다. 제안된 큐 서비스 방식을 이용하여 연결 수락 제어는 트래픽 왜곡의 영향을 계산할 수 없는 트래픽 왜곡의 영향이 실재로 존재한다는 가정 하에 트래픽 왜곡에 대한 영향에 종단간 지연을 보장함으로 서 연결 수락 가능 범위를 다양한 프레임의 길이에 대해 나타내었으며, 프레임의 길이가 클수록 제안된 큐 서비스 방식의 연결 수 락 범위가 지연 EDD방식과 비교해서 많은 차이를 보이지만 프레임의 길이를 점차 줄여갈수록 연결 수락 가능 범위가 지연 EDD 방식에 근접함을 나타내었다.

• 한국광학회지
• /
• 제11권6호
• /
• pp.411-417
• /
• 2000

SSC(Spot-size converter)가 집적된 1$1.3\mu{m}$ FP(Fabry-Perot)-LD(Laser Diode)에서 SSC 영역의 광도파로 구조가 단일모드광섬유와의 광결합 효율 및 정렬오차에 미치는 영향에 대해서 3차원 BPM(Beam Propagation Method)를 사용하여 알아보았다. 수지 taper의 경우 광결합효율을 향상하기 위해서는 taper 끝단에 충분한 길이의 직선도파로를 형성하는 것이 중요함을 알수 있었다. 또한 수평 taper 구조에서는 출사단 방향으로 도파로폭이 좁아지는 경우가 넓어지는 경우에 비해 유리하고, 수직 taper에 비해 완만한 도파로 경사가 필요함을 알 수있었다. 단일모드 광섬유와의 광결합 손실 및 정렬오차 허용도의 관점에서 좋은 특성을 주는 SSC 도파로 모양을 제시하였다.

• Journal of Advanced Marine Engineering and Technology
• /
• 제35권3호
• /
• pp.335-340
• /
• 2011

Building energy saving is one of the most important issues in these days. Control algorithm for energy saving should be designed properly to reduce power consumption in building. Recently, building energy system consists of hybrid energy system coupling with RE (Renewable Energy) source. In this paper, an optimum control algorithm for building energy saving is applied to BEMS (Building Energy Management System) by using an outdoor air temperature prediction strategy. BEMS coupling with renewable energy can control HVAC (Heating, Ventilating and Air-Conditioning) system effectively. In order to verify the effectiveness of building energy saving, BEMS was tested for several months at a laboratorial chamber with an air conditioner, fan and heater. To this end BEMS embedded control algorithm has been tested successfully.

• Interaction and multiscale mechanics
• /
• 제1권4호
• /
• pp.449-465
• /
• 2008

In this paper a general approach for studying the motion of a cantilever beam interacting with a 2D fluid flow is presented. The fluid is solved by a general purpose commercial computational fluid dynamics (CFD) package (FLUENT 6.2), while the structure is managed by means of a dedicated finite element method solver, coded in FLUENT as a user-defined function (UDF). A weak fluid structure interaction coupling scheme is adopted exchanging information at the end of each time step. An arbitrary cantilever beam can be introduced in the CFD mesh with its wetted boundaries specified; the cantilever can also interact with specified rigid and flexible walls through use of a non-linear contact algorithm. After a brief review of relevant scientific contributions, some test cases and application examples are presented.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2005년도 춘계학술대회 논문집
• /
• pp.867-872
• /
• 2005

This paper describes the measurement and location method of partial discharges in high voltage CV cables. Coupling capacitors were used to detect partial discharge signal. Impedance characteristic of the coupling circuit and an amplifier with a high Common Mode Rejection Ratio(CMRR) were studied to improve sensitivity of the circuit. From the calibration experiment, the sensitivity of the partial discharge detection circuit was about 100pC. Also, we confirmed that the location of partial discharges in cables can be estimated by calculation of time difference between the first pulse and the second one reflected from the other end of the cable.

• 마이크로전자및패키징학회지
• /
• 제18권1호
• /
• pp.7-13
• /
• 2011

According to increasing of data transfer rate, printed circuit board (PCB) is required improvement of transmission speed. Optical PCB and its packaging technology can be one of the solutions that overcome the limitations of conventional electrical PCB. The data transmission capacity will be increased 10 Tbps at 2015. To this end, studies on various OPCB technologies are being conducted. For cost-effective and high- performance OPCB, studies of optical coupling by polymer replication process are conducted. In this work, optical waveguide and optical fiber array block were sequentially fabricated by polymer pattern replication method. Using this method we successfully demonstrate low loss optical fiber coupling between optical waveguide and optical fiber arrays. And researches on flip chip bonding process and using electro-optic connectors for packaging are conducted.

• 대한전기학회논문지:전력기술부문A
• /
• 제53권3호
• /
• pp.168-174
• /
• 2004

This paper describes a new fault location algorithm based on the voltage equation at the relaying point using 6-phase current for untransposed 765㎸ parallel transmission lines. The proposed method uses the voltage and current collected at only the local end. By means of 3-phase circuit analysis theory to compensate the mutual coupling effects between parallel lines, the fault location is derived. The fault distance is determined by solving the 2nd distance equation based on KVL(Kirchhoff's Voltage Law). Extensive simulation results using EMTP(Electromagnatic Transients Program) have verified that the error of the fault location achieved is up to 4.56(%) in untransposed parallel transmission lines.

• ETRI Journal
• /
• 제32권1호
• /
• pp.148-150
• /
• 2010

This letter presents the design of a compact bandstop filter (BSF) operating at two frequencies. The proposed BSF consists of open-ended stepped impedance resonators (OSIR) and an end-shorted parallel-coupled microstrip line (E-PCML). The OSIRs are used to achieve the impedance-controlled stopband positions. The wide BSF bandwidths are achieved through enhanced coupling of the E-PCML. Explicit design guidelines are derived using a lossless transmission line model. To validate theoretical predictions, a prototype dual-band BSF operating at 900 MHz and 2,100 MHz with fractional bandwidths of 72% and 36%, respectively, is implemented in microstrip.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
• /
• pp.400-402
• /
• 2003

The inductive interference can be happened on some of the communication line that is located near by paralleled transmission line. The causes of inductive interference are magnetic coupling, capacitive coupling and residual voltage at neutral point of transmission line. In this paper, after grounding the one side of communication line, we have measured the voltage to ground at the other side of it. And we also have measured the voltage to ground at the end of it without grounding. As a result, we proved that the cause of inductive interference is the difference of ground voltages.