• Journal of the Institute of Convergence Signal Processing
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• v.5 no.2
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• pp.138-142
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• 2004

This paper proposes the design of the model following control system using the PID control structure. PID control system became model following control by inserting new pre-compensator in order to improve control performance in discrete-time region. Gain of the PID controller needs to be readjusted when response of system changes due to disturbance or load fluctuation. Performance of control system improves by joining neural network to PID control system because performance of control system depends largely on each PID gain in PID control system. And the games of the PID controller in the proposed control system are automatically adjusted by back-propagation algorithm of the neural network. Angular position of DC servo motor is selected as a plant in order to verify control performance in model following control. After it is applied to the position control system, it's performance is verified through computer experiment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.1
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• pp.1-5
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• 2018

This study analyzed the change of electrical characteristics of a photocoupler when a narrow-band electromagnetic wave was combined with the photocoupler. A magnetron (3 kW, 2.45 GHz) was used as the narrow-band electromagnetic source. The EUT was Photocoupler (6N139) and the input signal was divided into two types: a square pulse and the second signal is 0 V. The malfunction of the photocoupler was confirmed by monitoring the variation in the output voltage of the photocoupler. As a result of the experiment, changes in the malfunctioning was observed as the electric field was increased. There are three types of malfunction modes: delay, output voltage off, and fluctuation. Bit errors were analyzed to verify the electrical characteristics of the photocoupler by narrow-band electromagnetic waves. The result of this study can be used as basic data for the effect analysis of photocoupler protection and impact analysis of high-power electromagnetic waves.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1507-1517
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• 2023

Centrifugal pumps are a crucial part of nuclear power plants, and their dependable and safe operation is crucial to the security of the entire facility. Cavitation will cause the centrifugal pump to violently vibration with the large number of vacuoles generated, which not only affect the hydraulic performance of the centrifugal pump but also cause structural damage to the impeller, seriously affecting the operational safety of nuclear power plants. A closed cavitation test bench of a centrifugal pump is constructed, and a method for precisely identifying the cavitation state is proposed based on Complementary Ensemble Empirical Mode Decomposition (CEEMD) and Deep Residual Shrinkage Network (DRSN). First, we compared the cavitation sensitivity of pressure fluctuation, vibration, and liquid-borne noise and decomposed the liquid-borne noise by CEEMD to capture cavitation characteristics. The decomposition results are sent into a 12-layer deep residual shrinkage network (DRSN) for cavitation identification training. The results demonstrate that the liquid-borne noise signal is the most cavitation-sensitive signal, and the accuracy of CEEMD-DRSN to identify cavitation at different stages of centrifugal pumps arrives at 94.61%

• Journal of Photoscience
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• v.9 no.2
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• pp.134-137
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• 2002

PYP consists of a water-soluble apoprotein and 4-hydroxycinnamyl chromophore bound to Cys69 via thiolester linkage, Upon absorption of a photon, the photocycle is initiated, leading to formation of several photo-intermediates. Among them, M intermediate is important to understand the signal transduction mechanism of PYP, because it is a putative signaling state. As well known, the dynamics of a protein is closely correlated with the occurrence of its function. Here we report the results of IO ns molecular dynamics (MD) simulation for the M intermediate in aqueous solution and discuss the characteristic feature of this state from a viewpoint of structural fluctuation.

• Journal of the Korean Society of Combustion
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• v.13 no.2
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• pp.14-22
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• 2008

The CH* chemiluminescence of premixed flames and their dependency on fuel types has been experimentally investigated on laminar methane and propane premixed flames. The measured chemiluminescence intensities are observed linearly proportional to the fuel flow rate, which could be interpreted as the CH* chemiluminescence signal is linearly proportional to the heat release rate under fuel lean conditions. The effect of equivalence ratio could be expressed by an exponential function as ${I_{CH*}}^{\propto}\;a_1\;{\exp}(b_1{\Phi})$, where $a_1\;=\;0.00054$ and $b_1\;=\;4.60$ for methane and $a_1\;=\;0.0056$ and $b_1\;=\;5.02$ for propane. Oscillating flames showed the temporal fluctuation of chemiluminescence intensity: however, the time averaged values are virtually identical to those of quiescent flames under the same fuel flow rate and equivalence ratio conditions. This observation suggests that there is no significant flame stretch effect on chemiluminescence intensity, in average values.

• Phonetics and Speech Sciences
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• v.5 no.1
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• pp.11-16
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• 2013

This paper proposes robust feature extraction for accurate voice activity detection (VAD). VAD is one of the principal modules for speech signal processing such as speech codec, speech enhancement, and speech recognition. Noisy environments contain nonstationary noises causing the accuracy of the VAD to drastically decline because the fluctuation of features in the noise intervals results in increased false alarm rates. In this paper, in order to improve the VAD performance, harmonic-weighted energy is proposed. This feature extraction method focuses on voiced speech intervals and weighted harmonic-to-noise ratios to determine the amount of the harmonicity to frame energy. For performance evaluation, the receiver operating characteristic curves and equal error rate are measured.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.8
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• pp.1497-1505
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• 2010

The present study was performed to investigate the effect of aging on muscular activity of older subjects under the condition of fixed load muscle contraction. SEMG signals were recorded from old (46 women) and young (45 women) groups performing sustained isometric elbow flexion contraction with a fixed load during 30 seconds. Linear regression and mean square error (MSE) analysis with four characteristic variables (ARV, RMS, MDF, MNF) were used to compare the age-related difference (of local muscle fatigue and fluctuation of the amplitude and frequency) in the SEMG signal. The main results can be summarized as follows: During sustained muscle contraction with a fixed load: i) the MSE values of amplitude (ARV, RMS) and frequency (MDF, MNF) variables were more than 30% higher for the young than for the old adults; ii) the measures of local muscle fatigue (slope of the MDF and MNF) indicated greater fatigue in the old; and iii) the rate of increase of the SEMG amplitude was higher for the young than the old.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.257-261
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• 2001

This paper presents the implementation of wide-band RFIC amplifier operating from near 50MHz to 3GHz using Tachyonics SiGe HBT foundry. Voltage shunt feedback is used for the flat gain and the broad band impedance matching. Initial design parameters are calculated using the low frequency small signal analysis. Since the HBT model was not available at the design time, discrete tuning board was made for fine tuning in the low frequency range. Fabricated amplifier shows 12dB gain with 1dB fluctuation and PldB reaches 15dBm at 850MHz.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.411-414
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• 2000

Optical Triangulation Probes (OTPs) are widely used for their simple structure. high resolution, and long operating range. However, errors originating from speckle, inclination of the object, source power fluctuation, ambient light, and noise of the detector limit their usability. In this paper, we propose new design criteria for an error-reduced OTP. The light source module for the system consists of an incoherent light source and a multimode optical fiber for eliminating speckle and shaping a Gaussian beam Intensity profile. A diffuse-reflective white copy paper, which is attached to the object, makes the light intensity distribution on the change-coupled device(CCD). Since the peak positions of the intensity distribution are not related to the various error sources, a sub-pixel resolution signal processing algorithm that can detect the peak position makes it possible to construct an error-reduced OTP system

• Journal of Advanced Navigation Technology
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• v.13 no.6
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• pp.943-949
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• 2009

In this paper, the 5.9GHz WAVE(Wireless Access in Vehicular Environments) channel modeling is used by the Jakes channel model for the suitability of the fast wireless channel fluctuation. The performance analysed the fading signal constellation and the spectrum in the IEEE 802.11p spectrum mask, the Doppler effect, the modulation scheme. In addition, the vehicular speed, exactly the performance analysis the WAVE communication systems follow the Doppler effect.