• 한국ITS학회:학술대회논문집
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• 한국ITS학회 2005년도 제4회 추계학술대회 및 정기총회
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• pp.263-266
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• 2005

• 한국정보처리학회논문지
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• 제1권4호
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• pp.479-489
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• 1994

정보신호계열을 초고속으로 전송하기 위한 디지틀 광전송 시스템이 대용량화, 경 제화됨에 따라, 효율적으로 순수 정보신호계열을 신뢰성있게 전송할 수 있는 초고속 광전송 시스템용 전송로 부호의 선택이 현시점에서 중요한 문제로 대두되고 있다. 따라서 본 논문에서는 지금 까지 제안된 2치 unipolar 전송로 부호들 중 고속(100Mb/s 이상의 전송속도) 광전송 시스템으로 적합한 전송로 부호들을 우선 선택하여, 선택한 전송로 부호들 간의 성능 평가를 전송로 부호의 요구조건들, 즉 최대 동부호 연속수, 전송지연시간, 클럭 상승률, 마크율, 회로규모, 전송로 에러 감시 및 전력 스펙트럼에 따라 상호 비교 분석 한 결과, mBIZ부호가 최적의 초고속 광전송 시스템용 전송로 부 호임을 밝혔다.

• ETRI Journal
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• 제36권2호
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• pp.286-292
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• 2014

This paper presents a compact structure composed of an upper high-impedance transmission line, a middle extended parallel coupled line, and a pair of inter-coupled symmetrical stepped impedance stubs. Detailed investigation into this structure based on an equivalent circuit analysis reveals that this proposed structure exhibits a quasi-elliptic low-pass filtering response with three transmission zeros. Moreover, the positions of the three transmission zeros can be tuned and reallocated flexibly by choosing the proper circuit parameters. Finally, the design concept is validated through the design, fabrication, and measurement of two exemplary low-pass filters (LPFs) with one single unit and two cascaded asymmetric units. The measured results agree well with the simulated results. In addition, in the range of $1.42f_c$ to $7.03f_c$, the fabricated quasi-elliptic LPFs experimentally demonstrate a very wide upper-stopband of 20 dB using a compact size of only $0.0089{\lambda}_g{^2}$, where ${\lambda}_g$ is the guided wavelength of a $50{\Omega}$ transmission line at the central frequency.

• KIEE International Transactions on Power Engineering
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• 제3A권4호
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• pp.191-197
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• 2003

Accurate detection and classification of faults on transmission lines is vitally important. In this respect, many different types of faults occur, such as inter alia low impedance faults (LIF) and high impedance faults (HIF). The latter in particular pose difficulties for the commonly employed conventional overcurrent and distance relays, and if undetected, can cause damage to expensive equipment, threaten life and cause fire hazards. Although HIFs are far less common than LIFs, it is imperative that any protection device should be able to satisfactorily deal with both HIFs and LIFs. Because of the randomness and asymmetric characteristics of HIFs, their modeling is difficult and numerous papers relating to various HIF models have been published. In this paper, the model of HIFs in transmission lines is accomplished using the characteristics of a ZnO arrester, which is then implemented within the overall transmission system model based on the electromagnetic transients program (EMTP). This paper proposes an algorithm for fault detection and classification for both LIFs and HIFs using Adaptive Network-based Fuzzy Inference System (ANFIS). The inputs into ANFIS are current signals only based on Root-Mean-Square (RMS) values of 3-phase currents and zero sequence current. The performance of the proposed algorithm is tested on a typical 154 kV Korean transmission line system under various fault conditions. Test results demonstrate that the ANFIS can detect and classify faults including LIFs and HIFs accurately within half a cycle.

• 한국생산제조학회지
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• 제18권6호
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• pp.565-575
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• 2009

A forklift (also called a lift truck) is a powered industrial truck that is used to lift and transport materials. It has become an indispensable piece of equipment in manufacturing and warehousing operations. The modem forklift is equipped with automatic transmission to meet the requirement of loading and easy operation of the vehicle. This paper proposes the design of TECU(Transmission Electronic Control Unit) which is applied to PSD322-Axle transmission. Garofalo's control technique is generally used to the automatic transmission. We consider the work quality and market requirement that does not want to control engine throttle. This paper proposes new controller system which guarantees efficient speed changes with simple system. This new system does not control the engine throttle spontaneously. But it has the load of engine and vehicle as a maximum disturbance. The scope of the disturbance is limited to the stoll area of the torque converter. This paper proposes a ideal control commander that converges relative velocity of the input and ouput of a clutch into a zero. We design linear controller to execute the idea control commander. We applied the control algorithm to the forklift of PSD322-Axle type and the performance of this controller was verified.

• 한국전자파학회논문지
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• 제7권5호
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• pp.369-375
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• 1996

본 논문은 UHF대 역에서 S-평면 프로토타입을 사용한 마이크로스트립 대역통과 필터의 소형화를 기술하였다. 현대의 마이크로파 수신 사스템은 소형화와 더불어 더 훌륭한 성능을 갖는 필터를 요구하고 있다. 대역통과 S 평 면 프로토타입을 이용한 펼터의 설계는 이러한 요구들을 잘 충족시키고 있다. 대역통파 S-평면 프로토타엽은 원 하는 주파수대에서 transmission zero (전송영점)를 사용한 exact-synthesis법에 의하여 설계되고, 프로토타입의 각소자틀의 값은 컴퓨터에 의해 구현된다.

• 한국항행학회논문지
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• 제13권5호
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• pp.736-741
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• 2009

본 논문은 분할된 선형배열안테나를 사용하는 다중 사용자 MIMO 기술에서 코드북(codebook)을 운용 환경에 따라 최적화 하는 기술을 제안한다. 제안하는 기술은 공간상관도가 없는 MIMO 채널을 가정하여 디자인된 코드북을 각 순방향 링크의 송신 공간상관행렬을 이용하여 컬러링(coloring)하는 기술이며, 이를 위해 필요한 각 링크의 송신 상관행렬을 제한된 양의 long-term 피드백을 통해 피드백하는 기술을 제안한다. Zero-forcing maximum eigenmode transmission 기술을 사용하는 다중 사용자 MIMO 시스템에서, 제안하는 코드북 최적화 기술의 성능을 분석하였으며, 제안하는 기술이 적은양의 추가 피드백 정보량으로 다양한 운용 환경에 적응적으로 코드북을 최적화함을 보인다.

• 전기전자학회논문지
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• 제24권2호
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• pp.579-585
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• 2020

본 논문에서는 가시광을 사용하는 데이터 통신에서 광원의 플리커를 방지하기 위하여 On-off keying(OOK) 변조와 바이트반전 전송방식을 사용하였다. 송신부에서는 100 kHz의 구형파 전압을 부반송파로 사용하여 9.6 kbps의 기저대역 non-return-to-zero (NRZ) 입력데이터를 OOK 변조하고, 데이터의 비트열 형태에 관계없이 LED의 평균 광전력이 항상 일정하게 유지되도록 바이트반전 신호를 부가하여 전송하였다. 수신부에서는 대역통과 필터를 사용하여 주변의 120 Hz 잡음광의 간섭을 소거하고 OOK복조기를 사용하여 NRZ 형태의 원 신호를 복구하였다. 이러한 구조는 가시광 램프의 조명을 이용하여 근거리의 무선데이터 네트워크를 구축하는 데에 유용하다.

• Progress in Superconductivity
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• 제3권1호
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• pp.49-55
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• 2001

Josephson junction arrays were fabricated by DC magnetron sputtering, self-aligning and reactive ion etching technique. The Al native oxide, formed by thermal oxidation, was used as the tunneling barrier of Nb/$Al-A1_2$$O_3$Nb trilayer. The arrays have 2,000 Josephson junctions with the area of $14\mu\textrm{m}$ $\times$ $46\mu\textrm{m}$. The gap voltages were in the range of 2.5 ~2.6 mV and the spread of critical current was $\pm$11~14%. When operated at 70~94 ㎓, the arrays generated zero-crossing steps up to 2.1~2.4 V. To improve transmission of microwave power and prevent diffusion of oxygen into Nb ground-plane while depositing $SiO_2$dielectric, we applied a plasma nitridation process to the Nb ground-plane. The microwave power was well propagated in Josephson junction arrays with nitridation. The difference in microwave transmission 7an be interpreted by the surface impedance change depending on nitridation.

• Journal of electromagnetic engineering and science
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• 제16권1호
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• pp.19-23
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• 2016

This paper presents a novel design for dual-band bandpass filters. The proposed filters are applicable to the carrier aggregation of the TV white space (TVWS) band and long-term evolution (LTE) band for cognitive radio applications. The lower passband is the TVWS band (470-698 MHz) whose fractional bandwidth is 40 %, while the higher passband is the LTE band (824-894 MHz) with 8 % fractional bandwidth. Since the two passbands are located very close to each other, a transmission zero is inserted to enhance the rejection level between the two passbands. The TVWS band filter is designed using magnetic coupling to obtain a wide bandwidth, and the LTE band filter is designed using dielectric resonators to achieve good insertion loss characteristics. In addition, in the proposed design, a transmission zero is placed with cross-coupling. The proposed dual-band bandpass filter is designed as a two-port filter (one input/one output) as well as a three-port filter (one common input/two outputs). The measured performances show good agreement with the simulated performances.