• International Journal of Contents
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• v.10 no.4
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• pp.69-74
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• 2014

General location aware systems are only applied to indoor and outdoor environments using more than three transmitters to estimate a fixed object location. Those kinds of systems have environmental restrictions that require an already established infrastructure. To solve this problem, an Object Location Estimation (OLE) algorithm based on PTP (Point To Point) communication has been proposed. However, the problem with this method is that deduction of performance parameters is not enough and location estimation is very difficult because of unknown restriction conditions. From experimental tests in this research, we determined that the performance parameters for restriction conditions are a maximum transmission distance of CSS communication and an optimum moving distance interval between personal locations. In this paper, a system applied OLE algorithm based on PTP communication is implemented using a CSS (Chirp Spread Spectrum) communication module. A maximum transmission distance for CSS communication and an optimum moving distance interval between personal locations are then deducted and studied to estimate a fixed object location for generalization.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1469-1472
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• 1997

For system state estimation, existing LMS type esimators widely used. For example Kalman filter is one of them. In this paper, a state estimator is derived for the H$_{\infty}$ norm of the estimation error spectrum matrix to be minimized. For the solution of this problem classical NP interpolation problem is used. Also, by deriving the duality between the filter problem and the well-known H$_{\infty}$ control problem, another solution is obtained. The computer simuation results show that H$_{\infty}$ estimator has less estimation error and so this is better than the existing Kalman filter estimator.or.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.6 no.3
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• pp.148-151
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• 2013

A new direction of arrival estimation method using effects of model errors and sensitivity analysis is proposed. Since a desired signal is obtained after interference rejection through correction effects of model error, the effect of channel interference on the estimation is significantly reduced. Through simulation, we show that the proposed method offers significantly improved estimation resolution and accuracy relative to existing method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.9
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• pp.1783-1787
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• 2011

The slip frequency is included in feature frequency for fault diagnosis of rotor bar, so rotating rotor speed is needed. In this study, rotor slot harmonic(RSH) method is suggested for speed estimation of induction motor. When the rotor is rotating, motor current signal include the harmonic signal of back-emf voltage related with number of rotor slot. So from the power spectrum of current signal, the rotor speed can be founded. This method of rotor speed estimation gives the slip frequency, and the feature frequency of rotor bar fault can be calculated. Comparing with stroboscope speed meter, the error rate of suggested method is less than 0.1[%].

• The Journal of the Acoustical Society of Korea
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• v.20 no.4E
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• pp.24-30
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• 2001

This paper describes a fast harmonic estimation, referred to as Delta Adjustment (DA), using a low resolution pitch. The presented DA method is based on modification of the Generalized Dual Excitation (GDE) technique[1] which was proposed to improve speech enhancement performance. We introduce the GDE technique and modify it to be suitable for low bit rate harmonic coding that uses only an integer pitch estimate. Unlike the GDE, the DA matches a frequency-warped version of the original spectrum that conforms to a fixed pitch at all harmonic bands. In addition, complexity and performance of the presented method are described in comparison with those of the conventional Fractional Pitch (FP) based harmonic estimation. Experimental results showed that the DA algorithm significantly reduces the complexity of the FP method while maintaining the performance.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.736-740
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• 1991

EEG(Electroencephalogram) background signals can be represented as the sun of a conventional AR(Autoregressive) process and an innovation process, or a prediction error process. We have seen that conventional estimation techniques. such as least square estimates(LSE) or Gaussian maximum likelihood estimates(MLE-G) are optimal when the innovation process satisfies the Gaussian or presumed distribution. But when the data are contaminated by outliers, or artifacts, these assumptions are not met and conventional estimation techniques can badly fall and be strongly biased. It is known that EEG can be easily affected by artifacts. So we suggest a robust estimation technique which considerably performs well against those artifacts.

• Phonetics and Speech Sciences
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• v.3 no.3
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• pp.109-114
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• 2011

To estimate sound direction of arrival with a pair of microphones, a method based on Time Difference of Arrival (TDOA) estimation using the Cross Power Spectrum Phase (CPSP) function is largely used due to its simplicity and good performance. In this paper, we investigate CPSP maximum values for various SNRs and adverse environments, and propose a novel method to improve the estimation performance of sound direction of arrival. The proposed method applies a threshold to the CPSP values and increases the reliability of the estimated sound direction. Through computer simulation for various SNRs, we validate the effectiveness of the proposed method. When the threshold was set to 0.1, more than 90% of success rate of sound direction of arrival estimation has been achieved for directions of $10^{\circ}$, $40^{\circ}$, $70^{\circ}$ from the source location even with reverberation times of 0.1s.

• The Journal of the Acoustical Society of Korea
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• v.14 no.2E
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• pp.19-24
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• 1995

The maximum entropy method is a well-known parametric estimation method of the power spectrum with high-resolution for short-time signals. Although a parametric estimation method for the bispectrum was proposed in recent years, it is not easy to estimate the bispectrum with high resolution for relatively short-time signals of which the total length is about 1000 data points. In this paper, a bispectrum estimation method is proposed to estimate the high-resolution bispectrum even for the relatively short-time signals.

• Advanced Composite Materials
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• v.16 no.2
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• pp.115-134
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• 2007

This study proposes two new approaches for identifying damage patterns in a holed CFRP cross-ply laminate using an embedded fiber Bragg grating (FBG) sensor. It was experimentally confirmed that the reflection spectrum from the embedded FBG sensor was significantly deformed as the damage near the hole (i.e. splits, transverse cracks and delamination) extended. The damage patterns were predicted using forward analysis (a damage analysis and an optical analysis) with strain estimation and the proposed damage-identification method as well as the forward analysis only. Forward analysis with strain estimation provided the most accurate damage-pattern estimation and the highest computational efficiency. Furthermore, the proposed damage identification significantly reduced computation time with the equivalent accuracy compared to the conventional identification procedure, by using damage analysis as the initial estimation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.4
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• pp.310-317
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• 2013

In this paper an ESPRIT-based super-resolution time delay estimation algorithm is developed for real-time locating system (RTLS) and its performance is analyzed in various multipath environments. The performance of the existing correlation method for time delay estimation seriously degrades in multipath environments where the relative time delays of multipath signals are less than a PN chip. To solve the problem we shall develop a frequency domain super-resolution time delay estimation algorithm using the ESPRIT, the most representative super-resolution direction-of-arrival (DOA) estimation algorithm, and analyze its performance in various multipath environments.