• Journal of the Society of Naval Architects of Korea
• /
• v.49 no.4
• /
• pp.359-366
• /
• 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
• /
• v.5 no.4
• /
• pp.344-353
• /
• 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.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2005.11a
• /
• pp.7-12
• /
• 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.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.1A
• /
• pp.74-84
• /
• 2008

UWB radio systems have drawn attention during the last few years. These systems are the core technique for ubiquitous home and enable to co-exist with other narrow band systems over the same frequency without interfering them. But UWB signals have a very low power per pulse, so they are affected by strong narrow band interferences. Specially, IEEE 802.11a systems which operate around 5GHz overlap the band of UWB signals and they will interfere with UWB systems significantly. In this paper, we propose a novel narrow band interference suppression method based on singular value decomposition(SVD) algorithm for DS-UWB in IEEE 802.15.4a channel model. The proposed method is very effective and robust for both a single user DS-UWB system and a multiuser DS-UWB system to reduce the narrow band interference.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.36D no.6
• /
• pp.87-96
• /
• 1999

For analog optical transmission of narrow-band microwave signal, a novel all-optical linearization technique of electro-absorption (EA) optical modulator by using dual modulation scheme is proposed and theoretically investigated. By using the dual modulation scheme where the sub-modulator has a different length, DC bias and band-gap wavelength, the DC bias operation point where the third-order intermodulation products of ~30dB and the following increase of spurious free dynamic range (SFDR) of ~20dB wave achieved in sub-octave narrow band operation.

• Journal of KSNVE
• /
• v.4 no.3
• /
• pp.337-343
• /
• 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.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.35D no.8
• /
• pp.82-88
• /
• 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.

• Publications of The Korean Astronomical Society
• /
• v.15 no.spc1
• /
• pp.39-60
• /
• 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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.29 no.8
• /
• pp.98-103
• /
• 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
• /
• v.27 no.5
• /
• pp.643-646
• /
• 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.