• 대한전기학회논문지:시스템및제어부문D
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• 제51권2호
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• pp.86-88
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• 2002

An estimation method for the characteristic parameters in the low frequency signal is proposed in this paper. A low frequency signal is assumed to be modulated or distorted by high frequency terms. The algorithm proposed in this paper is designed to select set of local maximums in a successive manner, hence it is denoted as the iterative peak picking(IPP) algorithm. The IPP algorithm is operating in the time domain and is using only the comparison operation between two neighboring samples. Therefore, its computational complexity is very low and the delay caused by the computation is negligible, which make the real-time operation possible with economic hardware. The proposed algorithm is verified on the pitch estimation of speech signal and blood pulse estimation.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.555-555
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• 2001

The aims of this study are (1) to investigate the relation of irradiation mode, polymerzition shrinkage and degree of cure of composite resin and (2) it effect on microliakage of calss V restorations. VIP(BISCO Dental Products, Schaumburg, IL, USA) and Optilux 501(Demetron/Kerr, Danbury, CT, USA) curing lights were used for curing Z-250 composite resin following irradiation mode: VIP 200㎽, VIP 400㎽, VIP 600㎽, pulse-delay(200㎽ 3sec, 5min wait, 600㎽ 30sec), Optilux C mode, Optilux R mode.(omitted)

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.211-212
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• 1998

In this experiment, we developed a mind switching device which uses $\alpha$-wave with its amplitude varying between the eye-open and closed states. If the subject closes eyes, the switch toggles with a small delay. The circuit consists of an amplifier, a filter and a switch. An instrument amplifier is used fur high CMRR and for high input impedance. An 8th order Butterworth filter was able to reduce noise satisfactorily. The signal is then converted to a DC level, and finally a Schmitt trigger was used to generate a switching pulse.

• 한국정밀공학회지
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• 제19권1호
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• pp.158-164
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• 2002

This paper proposes the optimization of ultrasonic signal recognition in ferrite carbon steel weld zone using neural networks. For these purposes, the ultrasonic signals for defects as porosity, incomplete penetration and slag inclusion in the weld zone are acquired in the type of time series data. And then their applications evaluated feature extraction based on the time-frequency-attractor domain(peak to peak, rise time, rise slope, fall time, fall slope, pulse duration, power spectrum, and bandwidth) and attractor characteristics (fractal dimension and attractor quadrant) etc. The proposed neural networks system in this study can enhances performance of ultrasonic signal recognition.

• 한국산업융합학회 논문집
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• 제2권2호
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• pp.103-108
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• 1999

The paper describes a implementation of space vector pulse-width modulation voltage source inverter and interfacing of DSP using field programmable gate array(FPGA) for a induction motor vector control system. The implemented chip is included logic circuits for SVPWM, dead time compensation and speed detection using Quick Logic, QLl6X24B. The maximum operating frequency and delay time can be set to 110MHz and 6 nsec. The designed Application Specific Integrated Circuit(ASIC) for SVPWM can be incorporated with a digital signal processing to provide a simple and effective solution for high performance induction motor drives with a voltage source inverter. Simulation and implementation results are shown to verify the usefulness of ASIC in a motor drive system and power electronics applications.

• 수산해양기술연구
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• 제29권3호
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• pp.229-235
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• 1993

In this paper, a method of ghost cancelling for the television signals using complex adaptive filter is studied. The sin(x)/x signal is used as the reference signal a complex adaptive filter. The ghost cancelling characteristics considering the delay time, the attenuation, and the phase difference of multipath waves are investigated using horizontal sync pulse and color burst signal in composite video waveform. The influences of phase difference in ghost cancelling are investigated and the performances between the real processing and the complex processing are compared by the computer simulation. It was found that influences in ghost by phase difference are remarkably reduced by the complex adaptive filtering.

• Bulletin of the Korean Chemical Society
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• 제23권6호
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• pp.865-872
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• 2002

A systematic way of determining the equilibrium orientation of carbon monoxide (CO) in heme proteins using time-resolved polarized mid-IR spectroscopy is presented. The polarization anisotropy at pump-probe delay time of zero in the limit of zero photolysis and the angular distrbution function of CO are required to obtain the equilibrium orientation of CO. An approach is developed for determining the polarization anisotropy in the zero-photolysis limit from the anisotropy measured under finite photolysis conditions in an optically thick sample where the fraction of molecules photolyzed decreased as the pump pulse passes through and is absorbed by the sample. This approach is verified by measuring the polarization anisotropy of CO of carbonmonoxy myoglobin at various levels of photolysis. This method can be readily applied to other photoselection experiments determining precise angle between transition dipoles.

• Journal of the Optical Society of Korea
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• 제20권3호
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• pp.368-380
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• 2016

There is no doubt that adaptive optics (AO) is the most promising method to compensate wavefront disturbance in free space optics communication (FSO). In order to improve the performance of the AO system described by discrete-time linear system model with time-delay and implicit phase turbulent model, new controllers based on a Kalman filter and its extensions are proposed. Based on the standard Kalman filter, we propose a fading memory filter to deal with the ruleless strong interference; sequential and U-D filters are applied to reduce implementation complexity for the embedded controllers. Theoretical analysis and the numerical simulations show that the proposed fading memory filter can upgrade the performance for AO systems in consideration of the unforeseen strong pulse interference, and the sequential and U-D filters perform well compared with a Kalman filter.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1992년도 봄 학술발표회 논문집
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• pp.114-119
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• 1992

The main disadvantages of destructive testing methods are the delay in obtaining test results, the relatively high cost of testing, and the lack of reproducibility in the test results. As a result, nondestructive testing methods are generally used. There are three objectives in this paper. The first is to determine the equations of the compressive strength of concrete estimated by Schmidt hammer technique, ultrasonic pulse velocity method and combined method respectively in laboratory. The second is to determine the correction factors according to the concrete age which affects most in evaluating the compressive strength of in-situ concrete. The third is to examine the applicability of the equations to evaluation of the compressive strength of in-situ concrete structures.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권4호
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• pp.246-255
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• 2000

This paper deals with a novel full digital control method of the three-phase PWM inverter for UPS. The voltage and current of output filter capacitor as state variables are the feedback control input. In addition, a double deadbeat control consisting of a d-q current minor loop and a d-q voltage major loop, both with precise decoupling, have been developed. The switching pulse width modulation based on SVM is adopted so that the capacitor current should be exactly equal to its reference current. In order to compensate the calculation time delay, the predictive control is achieved by the current·voltage observer. The load prediction is used to compensate the load disturbance by disturbance observer with deadbeat response. The experimental results show that the proposed system offers an output voltage with THD less than 2% at a full nonlinear load.