• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12C
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• pp.1149-1155
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• 2007

In this paper, we propose a new overlap and add speech synthesis method which demonstrates improved continuity performance. The proposed method uses a weighted phase error function and minimizes the wave discontinuity of the synthesis signal, rather than the phase discontinuity, to estimate the mid-point phase. Experimental results show that the proposed method improves the continuity between the synthesized signals relative to the existing method.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.10 s.115
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• pp.1044-1049
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• 2006

The vibration exciter with the accurate calibration requires a low distortion along a single axis over a wide range of frequency. The fabricated piezoelectric exciter was composed of a base, piezoelectric element(Venitron PZT 5A), electrode and seismic mass. Its performance characteristics is evaluated the Mach-Zehnder optical fiber interferometer. The phase of the optical wave passing through the optical fiber around the piezoelectric element was related the vibrational amplitude with a change of the applied sinusoidal voltage on the piezoelectric element. The dynamic characteristics of vibration exciter can be obtained by measuring the vibrational amplitude with a sinusoidal applied voltage on the piezoelectric element. The sensitivity of the fabricated piezoelectric exciter had a 0.4 nm/V which was uniform up to 20 kHz.

• Earthquakes and Structures
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• v.2 no.2
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• pp.171-187
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• 2011

Rational scaling of design earthquake ground motions for tall buildings is essential for safer, risk-based design of tall buildings. This paper provides the structural designers with an insight for more rational scaling based on drift and input energy demands. Since a resonant sinusoidal motion can be an approximate critical excitation to elastic and inelastic structures under the constraint of acceleration or velocity power, a resonant sinusoidal motion with variable period and duration is used as an input wave of the near-field and far-field ground motions. This enables one to understand clearly the relation of the intensity normalization index of ground motion (maximum acceleration, maximum velocity, acceleration power, velocity power) with the response performance (peak interstory drift, total input energy). It is proved that, when the maximum ground velocity is adopted as the normalization index, the maximum interstory drift exhibits a stable property irrespective of the number of stories. It is further shown that, when the velocity power is adopted as the normalization index, the total input energy exhibits a stable property irrespective of the number of stories. It is finally concluded that the former property on peak drift can hold for the practical design response spectrum-compatible ground motions.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.180-182
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• 2001

Input Current Correction of Single-Phase Buck Rectifier is studied in the paper. To sinusoidal waveform the input current with a near-unity power factor over a wide variety of operating conditions, the output capacitor is operated with voltage reversibility for the supply by arranging the auxiliary diode and power switching device. Then the output voltage is superposed on the input voltage during on time duration of power switching devices in order to minimize the input current distortion caused by the small input voltage when changing the polarity. The tested setup, using two insulated-gate bipolar transistors(IGBT) and a microcomputer, is implemented and IGBT are switched with 20[kHz], which is out of the audible band. Moreover, a rigorous state-space analysis is introduced to predict the operation of the rectifier. The simulated results confirm that the input current can be sinusoidal waveform with a near-unity power factor and a satisfactory output voltage regulation can be achieved.

• Current Optics and Photonics
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• v.4 no.4
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• pp.267-272
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• 2020

The propagation of a truncated Airy beam with spatial phase modulation (SPM) is investigated in Kerr nonlinearity with an optical lattice. Before the truncated Airy beam enters the optical lattice, a sinusoidal phase is introduced on the wave-front of the beam. The effect of the spatial phase modulation and optical lattice on propagation behavior is analyzed by direct numerical simulation. It is found that the propagation direction of a truncated Airy beam can be effectively controlled by adjusting the values of phase shift. The effects of optical amplitude, truncation factor, spatial modulation frequency, lattice period and lattice depth on the propagation are discussed in detail. By choosing a high modulation depth, the finite-energy Airy beam can be deflected with a large deflection angle in an optical lattice.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.180-184
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• 2007

For driving a sinusoidal type permanent magnet synchronous motor with a maximum continuous torque, a $120^0$ delayed three phase sinusoidal current input which matched with the absolute rotor position is needed at a stator coil. So, the detection of absolute rotor position is required inevitably. Thus the right angle relationship between stator magnetic field and rotor magnetic field has to be preserved at a stator by this commutation action. The detection of a absolute position for the commutation can be made generally by the output signal analysis of the encoder attached at a motor shaft. This study purposes to design signal processing logic circuits which can detect the absolute position of motor with a modem encoder system and generate the three reference wave for making sinusoidal current input at a stator coil.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.2064-2071
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• 1998

A new digital clock level translator has been designed in order to produce a clock source of the internal logic circuits. The translator output has 50% duty ratio from small sinusoidal input such as TCXO which oscillates itself in poratable components. The circuit consists of positive and negative comparators, RS latch, charge pump, and reference vol- tage generator. It detects pulse width of the output waveform and feedbacks the control signal to the input com-parator. It detects pulse width of the output waveform and feedbacks the control signal to the input com-parator reference, producing output waveform with valid 50% duty ratio of the digital signal level. The designed level translator can be used as a sampling clock source of ADC, PLL and the colck source of the clock synthesizer. The circuit wasdesigned in a 0.8.mu.m analog CMOS technology with double metal, double poly, and BSIM3 circuit simulation model. From our experimental results, a stable operating characteristics of 50 +3% duty ratio was obtained from the sinusoidal input wave of 370 mV.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.5
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• pp.1018-1024
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• 2011

For the driving of the sinusoidal type permanent magnet synchronous motor with a maximum continuous torque, the 1200 delayed three phase sinusoidal current inputs which matched with the absolute rotor position are needed at the stator coil. Therefore, the detection of a absolute rotor position is required inevitably. And the right angle relationship between stator magnetic field and rotor magnetic field has to be preserved at a stator by this commutation action. The detection of a absolute position for the commutation can be made generally by the output signal analysis of the encoder attached at a motor shaft. The purposes of this study are to design signal processing logic circuits which could detect the absolute position of motor with a modern encoder system and generate the three reference wave for making sinusoidal current input at a stator coil.

• The Journal of the Acoustical Society of Korea
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• v.18 no.5
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• pp.68-77
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• 1999

The paper looked into the effects of the spectral properties (waveform) of the high intensity focused ultrasound on suppression of the ultrasonic cavitation. Three different types of ultrasound were considered in the study, which were sinusoidal (1 MHz, 5 MPa), frequency modulated (from 1 MHz to 6 MHz for 10 ㎲, 5 MPa), asymmetrically shocked (fundamental frequency 1 MHz, peak positive pressure 12 MPa, peak negative pressure -4 MPa). The temporal response of an air bubble in water initially 1 ㎛ in radius to each type of the ultrasound was predicted using Gilmore bubble dynamic model and Church's rectified gas diffusion equation. It was shown that the radially pulsating amplitude of the bubble was greatly reduced for the frequency modulated wave and was little decreased for the shock wave, compared to the case that the bubble was exposed to the sinusoidal wave. It is interesting that the bubble response to the frequency modulated wave remains similar when the frequency component of the modulated ultrasound is beyond the bubble resonant frequency 3 MHz. This implies that, although the ultrasound is modulated up to 3MHz rather than up to the present 6 MHz, it is likely to produce similar cavitation suppression effects. In practice, it means that a typical narrow band ultrasonic transducer can be taken to generate an appropriate frequency modulated ultrasound to reduce cavitation activity. The present study indicates that ultrasonic cavitation may be suppressed to some extent by a proper spectral modification of high intensity ultrasound.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.2
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• pp.121-127
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• 2015

A reduction of motor performance due to brain disorders can be screened by evaluating force tracking capabilities (FTCs). Existing studies have examined FTCs mainly using simple sinusoidal waves, of which repeated profiles have a critical limitation due to a learning effect in force tracking. The present study examined the effects of personal factors (age and gender) and sinusoidal wave factors (central force and complexity) on FTCs of healthy adults using composite sinusoidal wave profiles (CSWPs). FTCs were measured using Finger $Touch^{TM}$ for 30 seconds and quantified in terms of time within the target range (TWR, accuracy measure) and relative RMSE (RRMSE, variability measure). A total of 90 healthy adults in 20s to 70s with the equal gender ratio participated in the experiment consisting of combinations of 2 central force levels (6 N and 10 N) and 2 complexity levels (approximate entropy, ApEn = 0.03 and 0.06) of CSWPs. Significantly decreased FTCs (lower TWR and higher RRMSE) were found in aged adults, females, the low central force, and the high complexity. The detailed FTC decrements include a 43% reduced TWR and a 85% increased RRMSE of older adults in 70s as compared to those in 20s, a 17% reduced TWR and a 17% increased RRMSE of female as compared to those of male, a 30% reduced TWR and a 108% increased RRMSE at central force = 6N when compared to those at central force = 10N, and a 19% reduced TWR and a 30% increased RRMSE at ApEn = 0.06 as compared to those at ApEn = 0.03. The characteristics of FTCs for CSWPs can be of use in establishing an assessment protocol of motor performance for screening brain disorders.