• Journal of IKEEE
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• v.22 no.4
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• pp.999-1005
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• 2018

This paper proposed a search-based high resolution frequency estimation method in power systme. The proposed frequency estimation method adopts a slope-based adaptive search as a base of adaptive estimation structure. The architectural and operational parameters in this adaptive algorithm are changed using the information from context layer analysis of the signals including a localized full-search of spectral peak. The convergence rate of the proposed algorithm becomes much faster than those of other conventional slope-based adaptive algorithms by effectively reducing search range with the application of the localized full-search of spectrum peak. The improvements in accuracy and convergence rate of the proposed algorithm are confirmed through the performance comparison with other representative frequency estimation methods, such as, DFT(discrete Fourier transform) method, ECKF(extended complex Kalman filter), and MV(minimum variable) method.

• Journal of Advanced Navigation Technology
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• v.7 no.2
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• pp.118-127
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• 2003

ITU-R recommends general methodology to provide current and future mobile communication services and 12 parameters to calculate terrestrial spectrum requirements. In this paper we analyzed 12 parameters suggested by ITU-R Recommendation and provided a method to determine a specific parameter value in a specific region. We calculated spectrum requirements and network resources for year 2010 in Korean mobile environment by applying parameter values acquired in parameter analysis method of this paper. And we analyzed the variation of spectrum requirements by calculating spectrum requirements depending on variation of parameters for future mobile communication services.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.474-477
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• 2013

As the market-based spectrum policy is introduced, an interest in the economic value of the frequency is increasing. Research and practical applications concerning the methodology for the estimation of the economic value of the frequency and its determinants are actively engaged, which are used for setting a reserve price and bid price of spectrum auction and a spectrum clearance cost. In this study, by the analysis of the spectrum valuation methodology, we derive the changes in the factors affecting the valuation and propose to apply improved. In the model frequency value is consist of technical value, commercial value and strategic value, we find the dynamics of fluctuation factors and suggest how to apply them to spectrum policy.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.659-661
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• 2003

How many leafs the forest has can be very important information to understand the forest is healthy or not, or it is growing or declining. However until now, very much labor and long time is needed to measure it. The purpose of this study is to develop the method that estimate how many leafs there are at the forest.

• Proceedings of the KSPS conference
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• 2003.10a
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• pp.25-28
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• 2003

The aim of this paper is to analyze the pathological voice by separating signal into periodic and aperiodic part. Separation was peformed recursively from the residual signal of voice signal. Based on initial estimation of aperiodic part of spectrum, aperiodic part is decided from the extrapolation method. Periodic part is decided by subtracting aperiodic part from the original spectrum. A parameter HNR is derived based on the separation. Parameter value statistics are compared with those of Jitter and Shimmer for normal, benign and malignant cases.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.5
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• pp.7-14
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• 1998

In this paper, Fractal analysis applied to evaluate machined surface profile. The spectrum method was used to calculate fractal dimension of generated surface profiles by Weierstrass-Mandelbrot fractal function. To avoid estimation errors by low frequency characteristics of FFT, the Maximum Entropy Method (MEM) was examined. We suggest a new criterion to define the MEM order m. MEM power spectrum with our criterion is proved to be advantageous by the comparison with the experimental results.

• ETRI Journal
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• v.26 no.1
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• pp.45-47
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• 2004

A resolution enhancement method for estimating the direction-of-arrival (DOA) of signals is presented. The proposed method is by virtually expanding a real array into virtual arrays and then averaging the spatial spectrum of the virtual arrays, each of which has a different aperture size. Superior DOA resolutions are shown in comparison with the standard algorithm, MUltiple SIgnal Classification (MUSIC), for incoherent signals incident on a uniform circular array.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.3
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• pp.515-523
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• 1997

A high resolution algorithm is presented for resolving multiple coherent spread spectrum signals that are incident on an equispaced linear array. Unlike the conventional noise-eigenvector based methods, this algorithm makes use of the signal eigenvectors of the array spectral density matrix that are associates with eigenvalues that are larger than the sensor noise level. Simulation results are shown to demonstate the high performance of the proposed approach in comparison with MUSIC in which coherent signal subspace method (CSM) is employed.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.54.2-54.2
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• 2019

Mass and radius of a neutron star in low-mass X-ray binary (LMXB) can be estimated simultaneously when the observed light curve and spectrum show the photospheric radius expansion feature. This method has been applied to 4U 1746-37 and the mass and radius were found to be unusually small in comparison with typical neutron stars. We re-estimate the mass and radius of this target by considering that the observed light curve and spectrum can be affected by other X-ray sources because this LMXB belongs to a very crowded globular cluster NGC 6441. The new estimation increases the mass and radius but they do not reach the typical values yet.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.1
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• pp.87-94
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• 2009

Noise estimation and suppression are a crucial factor of many speech communication and recognition systems. In this paper, proposed algorithm is based on the ratio of variance normalized of noisy power spectrum in time-frequency domain. Our proposed algorithm tracks the threshold and controls the trade-off between residual noise and distortion. This algorithm is evaluated by the ITU-T P.835 signal distortion (SIG) and segment signal to noise ratio (SNR), and is superior to the conventional methods.