• 대한조선학회논문집
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• 제49권4호
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• pp.359-366
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• 2012

This is the final one of the two companion papers dealing with accuracy of accumulated fatigue damage estimation under wide band process. It is stated that four kinds of wide band models exist: typed of equivalent stress, combined PDF, correction factor, and damage combination. For the idealized ESDs from full scale measurement data on an 8100TEU container vessel, fatigue damages are compared for a narrow band prediction model based on Rayleigh PDF and five wide band fatigue prediction models of Dirlik, Wirsching-Light, Jiao-Moan, Benasciutti and DNV. DNV model consistently overestimates fatigue damages regardless of variation of ESDs. Predictions by Jiao-Moan model, which is understood as standard method for design of offshore platforms, are also in conservative side. Best accuracy is found from the results by Dirlik and Benasciutti models, but Benasciutti model is preferred since it can easily combined with narrow band fatigue damage based on Rayleigh PDF.

• Journal of Communications and Networks
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• 제5권4호
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• pp.344-353
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• 2003

Ultra-wideband (UWB) technology is gaining increasing interest for its potential application to short-range indoor wireless communications. Utilizing ultra-short pulses, UWB baseband transmissions enable rich multipath diversity, and can be demodulated with low complexity receivers. Compliance with the FCC spectral mask, and interference avoidance to, and from, co-existing narrow-band services, calls for judicious design of UWB pulse shapers. This paper introduces pulse shaper designs for UWB radios, which optimally utilize the bandwidth and power allowed by the FCC spectral mask. The resulting baseband UWB systems can be either single-band, or, multi-band. More important, the novel pulse shapers can support dynamic avoidance of narrow-band interference, as well as efficient implementation of fast frequency hopping, without invoking analog carriers.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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• pp.7-12
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• 2005

A compact microstrip band-selective filter for ultra-wideband (UWB) radio system is proposed. The filter combines the traditional short-circuited stub highpass filter and coupled resonator bandstop filter on both sides of the mitered 50-ohm microstrip line. To realize the pseudo-highpass filtering characteristic over UWB frequency band (3.1 GHz to 10.6 GHz), a distributed highpass filter scheme is adopted. Three coupled resonators are utilized to obtain the band stop function at the desired frequency band. By meandering the coupled resonators, there is 29% reduction in footprint compared to the traditional bandstop filter using L-shaped resonators. The measured results show that the filter has a wide passband of 146.7 % (2.1 GHz to 10.15 GHz) with low insertion loss and the stop band of 7.42 % (5.32 GHz to 5.73 GHz) for 3-dB bandwidth. The measured group delay is less than 0.7 ns within the passband except the rejection band.

• 한국통신학회논문지
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• 제33권1A호
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• pp.74-84
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• 2008

UWB(ultra wideband)는 기존의 무선통신망 시스템에게 간섭을 주지 않고 공존할 수 있는 매력적인 기술로 유비쿼터스 홈 실현을 위한 핵심기술로 인식되고 있다. 하지만 UWB 신호는 펄스 당 매우 낮은 에너지를 갖기 때문에 동일한 주파수 대역을 사용하는 협대역 통신시스템들에 의해서 강한 간섭을 받게 된다. 특별히 5GHz에서 작동하는 IEEE 802.11a 시스템은 FCC에서 규정한 UWB 신호의 대역폭과 겹쳐지게 되고 UWB 시스템에게 심각한 간섭효과를 준다. 본 논문에서는 IEEE 802.15.4a 채널환경에서 대역제한된 AWGN으로 모델링한 IEEE 802.11a 간섭신호가 DS-UWB 시스템에 미치는 간섭효과를 살펴보고 특이값 분해 알고리즘을 이용하여 수신된 신호로부터 IEEE 802.11a 신호를 추출하여 간섭을 억압하는 기법을 제안한다. 특이값 분해 알고리즘이 적용된 간섭억압기법을 통하여 단일 사용자 DS-UWB 시스템과 다중 사용자 DS-UWB 시스템에서 BER 성능이 향상된 것을 확인하였다.

• 전자공학회논문지D
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• 제36D권6호
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• pp.87-96
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• 1999

협대역 마이크로파 아날로그 광전송을 위한, 이중 변조구조를 이용한 새로운 전광 전계흡수 광변조기의 선형화 방법이 제안되었으며, 이론적으로 고찰되었다. 주-변조기와 소자 길이, 흡수층의 밴드갭 파장 그리고 DC 바이어스 전압을 달리하는 부-변조기의 주-변조기와의 이중 변조구조를 적용하여, 주-변조기의 3차 비선형 왜곡 성분인 CTB(composite triple beat distortion)를 최소화하는 동작점이 작은 바이어스전압으로 이동함과 더불어 ~30dB의 CYB의 억제효과를 얻을 수 있었다. CTB의 억제에 따라 협대역 채널 대역에서의 ~20dB 동작영역의 향상을 이룰 수 있었다.

• 소음진동
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• 제4권3호
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• pp.337-343
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• 1994

A method of the leak detection from the pipe system by using accelerometer is proposed. The signal detected from accelerometer is proved experimentally to be a dispersive wave. Based on the experiments, a method using the narrow band pass filter and the unit impulse response function is analyzed. The method uses the characteristics of the unit impulse response function, that the function is available evenin the narrow band signal because, unlike the cross correlation, it is normalized by the auto spectrum. The accelerometer is quite easier to use than the hydrophone in adapting to the pipe system.

• 전자공학회논문지D
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• 제35D권8호
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• pp.82-88
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• 1998

We propose and design a new type of anrrow band-pass optical filter based on two fiber gratings with different reflection wavelength. The ripples occur in the spectra of the filter with two uniform fiber gratings. Our simulation results also show that the ripples disappear with the fiber gratings apodized to both gaussian and hyperbolic tangent function. The hyperbolic tangent function seems to be a better apodization function for improving the filter's performance in terms of narrow pass bandwidth and high transmission.

• 천문학논총
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• 제15권spc1호
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• pp.39-60
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• 2000

We will discuss two-dimmensional spectrophotometry including long-slit spectroscopy and narrow-band imaging. The basic principles, applications, and techniques of observations and data reduction of spectroscopy and spectrophotometry for extended objects are described. This discussion will focus on practical long-slit spectroscopy using a Cassegrain spectrograph attached with 2 or 4m class telescopes and on imaging spectrophotometry using narrow-band interference filter sets. We will discuss scientific applications.

• 조명전기설비학회논문지
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• 제29권8호
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• pp.98-103
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• 2015

Power plant is that very high reliability when industrial and economic impact on the overall electric power system is required, it is essential to improve the reliability, especially the fault prediction diagnosis. Since an accident caused by the partial discharge in the power plant is above state has a faster response characteristic than the other indications in the case of any, the partial discharge generated in the power plant immediately detect the deterioration of insulation due to the accident of the power plant and the non-drawn It should prevent or reduce. Partial Discharge Measuring Systems for UHV SF6 Gas Insulated Switchgear and power transformer on site installed has some probability of abnormal recognition in case of non-flexible deal with on site noise. Many methode to eliminate these kinds of noises, UHF Detection System is chosen as purchase description in Korea, but this system having a bandwidth between 500MHz 1.5GHz wide band. Initial install periods(about 20 years ago), this band had no strong signal source, but in these days this wide band have strong signals, such as LTE. So, module described in this paper is designed as simultaneously use with wide and narrow band for solve this noise problem, and introduce this system.

• ETRI Journal
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• 제27권5호
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• pp.643-646
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• 2005

This letter proposes a band-pass filter (BPF) with two transmission zeros based on a combination of parallel coupling and end coupling of half-wave transmission lines. The fabricated BPF exhibited a narrow bandwidth and two transmission zeros near the pass-band due to the end-coupled and shielding waveguide. At the center operation frequency of 60 GHz, the 20 dB bandwidth of the BPF is 1.0 GHz, which is almost 2% of the center operation frequency, and the insertion loss is 3.12 dB. Two transmission zeros reach approximately 40 dB at 58.5 and 62.5 GHz. The simulation results almost agree with the measured results.