• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.1945-1955
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• 2018

High frequency signal injection (HFI) is an alternative method for estimating rotor position of interior permanent magnet synchronous motor (IPMSM). The general method of frequency and amplitude selection is based on error tolerance and experiments, and is usually set with only one group of HF parameters, which is not efficient for different working modes. This paper proposes a novel rotor position estimation scheme by HFI with optimized frequency and amplitude, based on the mathematic model of IPMSM. The requirements for standstill and low-speed operational modes are met by applying this novel scheme. Additionally, the effects of the frequency and amplitude of the injected HF signal on the position estimation results under different operating conditions are analyzed. Furthermore, an optimization method for HF parameter selection is proposed to make the estimation process more efficient under different working conditions according to error tolerance. The effectiveness of the propose scheme is verified by the experiments on an IPMSM motor prototype.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1655-1658
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• 1991

This paper considers the design and analysis of one-step ahead optimal and adaptive controllers, under the restriction that a known constraint on the input amplitude is imposed. It is assumed that the discrete-time single-input, single-output system to be controlled is linear, except for inequality constraints on the input. The objective function to be minimized is an one-step quadratic function, where polynomial weights on the input and output are included. Both the known parameter and unknown parameter (indirect adaptive controller) cases are examined.

• Journal of the Korean Institute of Telematics and Electronics
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• v.6 no.4
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• pp.1-7
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• 1969

A Series Inverter circuit is analyzed and Fourier analysis is applied to its output waveform. It is proved that under the optimum condition the Output is nearly sinusoidal wave which contains only odd harmonic Components and the relative amplitude of the hramonic components are expressed with very simple formula which contain only "Q" of the circuit as a parameter.parameter.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.2
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• pp.147-154
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• 1999

A new approach to conducting the vibration parameters identification algorithm is proposed. The approach employs the concept of modal amplitude ratio implemented in a mode shape estimation. The accuracy of the improved Ibrahim Time Domain identification algorithm in extracting structural modal parameters from free response functions has been studied using computer simulated data for 9 stations on the two-span continuous beam. Simulated responses from the lumped and distributed parameter system demonstrate that this algorithm produces excellent results, even in the 300% noise response.

• Proceedings of the Acoustical Society of Korea Conference
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• 1984.12a
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• pp.57-61
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• 1984

In this study, the system is proposed which can be used for recognition of Koean single vowles "ㅏ, ㅓ, ㅗ, ㅜ, ㅡ, ㅣ, ㅐ, ㅔ, ㅚ,", and automatic recognition is processed using $\mu$-computer. 3 men of not-being-studied are participated in this experiment. Using the period of vowels, one part of the steady state is selected for high speed recognition, and amplitude comparison method, LPC, PARCOR, and Formant are used for parameter of recognition. Formant is obtained by peak picking method using LPC, and then vowels are recognized by amplitude comparison method, LPC, PARCOR, and Formant. As a result, Recognition rates are 90.1% for amplitude comparison method, 93.1% for LPC, 100% for PARCOR, 88.8% for using formant.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.553-558
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• 1998

The calibrating method for an electrochemical Probe, neglecting the effect of the normal velocity on the mass transport, can cause large errors when applied to the measurement of wall shear rates in thin wavy flow with large amplitude waves. An extended calibrating method is developed to consider the contributions of the normal velocity. The inclusion of the turbulence-induced normal velocity term is found to have a negligible effect on the mass transfer coefficient. The contribution wave-induced normal velocity can be classified on the dimensionless parameter V. If V above a critical value of V, $V_{crit}$, the effects of the wave-induced normal velocity become larger with an increase in V. IF V its effects negligible for V < $V_{crit}$. The unknown shear rate is numerically determined by solving the 2-D mass transport equation inversely. The president inverse method can predict the unknown shear rate more accurately in thin wavy flow with large amplitude waves than the previous method.

• Structural Engineering and Mechanics
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• v.66 no.1
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• pp.113-124
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• 2018

In the present paper, we have considered a layered medium of two semi-infinite nonlocal elastic solids with intermediate transversely isotropic magnetothermoelastic solid. The intermediate slab is of uniform thickness with the effects of two temperature, rotation and Hall current and with and without energy dissipation. A plane longitudinal or transverse wave propagating through one of the nonlocal elastic solid half spaces, is made incident upon transversely isotropic slab and it results into various reflected and refracted waves. The amplitude ratios of various reflected and refracted waves are obtained by using appropriate boundary conditions. The effect of nonlocal parameter on the variation of various amplitude ratios with angle of incidence are depicted graphically. Some cases of interest are also deduced.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.395-400
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• 2015

Obtaining the parameters for PID controllers based on limit cycle information for the process in a relay controlled feedback loop has become an accepted practical procedure. If the form of the plant transfer function is known, exact expressions for the limit cycle frequency and amplitude can be derived so that their measurements, assumed error free, can be used to calculate the true parameter value. In the literature, parameter estimation for an assumed form of the plant transfer function has generally been considered for disturbance free cases, except a recently published work of the author. In this paper additional simulation results are reported on exact parameter estimation from relay autotuning under static load disturbances.

• Journal of Electrical Engineering and Technology
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• v.7 no.2
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• pp.163-170
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• 2012

This paper presents a DFT (Discrete Fourier Transform) based estimation algorithm for the parameters of a low-frequency oscillating signal. The proposed method estimates the parameters, i.e., the frequency, the damping factor, the mode amplitude, and the phase, by fitting a discrete Fourier spectrum with an exponentially damped cosine function. Parameter estimation algorithms that consider the spectrum leakage of the discrete Fourier spectrum are introduced. The multi-domain mode test functions are tested in order to verify the accuracy and efficiency of the proposed method. The results show that the proposed algorithms are highly applicable to the practical computation of low-frequency parameter estimations based on DFTs.

• Journal of Acupuncture Research
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• v.29 no.6
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• pp.57-71
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• 2012

Objectives : The purpose of this study is to find the effects of Sa-Am stomach tonifying acupuncture on radial pulse through the parameters difference. Methods : Forty healthy subjects participated in this study, acupuncture group and control group were divided. Radial pulse were measured using 3 dimensional pulse imaging system(DMP-3000). 19 parameters that significantly changed were selected after comparing between acupuncture group and control group. Then, 19 parameters were analyzed before, immediately after, 30 minutes after and 60 minutes after acupuncture in acupucture group. Results : 1. Heart rate, pulse period, T/T1, T2/T, T4/T, T5/T, T-T4, (T-T4)/T and T4/(T-T4) significantly changed after acupuncture. 2. H1 Amplitude, H2 Amplitude, H4 Amplitude and H5 Amplitude significantly changed after acupuncture. 3. Area of Pulse Wave, Systolic Pulse Area, Diastolic Pulse Area and Area of W significantly changed after acupuncture. 4. AIx/HR significantly changed after acupuncture. Conclusion : Stomach Tonifying Acupuncture exerts an influence on radial pulse parameters. Further radial pulse change study on various acupuncture treatment is required.