• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.159-162
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• 1998

Speech synthesis coding is classified into three categories: waveform coding, source coding and hybrid coding. To obtain the synthetic speech with high quality, the synthesis by waveform coding is desired. However, it is difficult to apply waveform coding to synthesis by syllable or phoneme unit, because it does not divide the speech into excitation and formant component. Thus it is required to alter the excitation in waveform coding for applying waveform coding to synthesis by rule. In this paper we propose a new pitch alteration method that minimizes the spectrum distortion by using the behavior of cepstrum. This method splits the spectrum of speech signal into excitation spectrum and formant spectrum and transforms the excitation spectrum into cepstrum domain. The pitch of excitation cepstrum is altered by zero insertion or zero deletion and the pitch altered spectrum is reconstructed in spectrum domain. As a result of performance test, the average spectrum distortion was below 2.29%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.26-29
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• 2002

The ramp waveform has recently been introduced to erase wall charges of the previously selected cells for plasma display. However. the ramp waveform can't completely remove wall charges. In this paper. we suggested new erase waveform having a complex with close width pulse and ramp pulse for complete erasing. The erasing margin of suggested waveform is wider than the conventional waveform. Moreover. suggested wave form can reduce the erasing time compared.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.341-349
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• 2022

When designing a new RNSS signal, the performance analysis for the legacy signal providing the same service, is required to determine the performance requirements. However, there are few studies on the secured service (SS) signal performance analysis, and the waveform is the only published information on the signal design component of the SS signal. Therefore, in this paper, we introduce several figures-of-merit (FoMs) that can be used for performance analysis in terms of the waveform. And then, we calculate the FoMs, such as autocorrelation main peak to secondary peak ratio (AMSR), spectral efficiency, Gabor bandwidth, multipath error, and jamming resistance quality factor, for the existing SS signals and discuss the analysis results. Finally, we conclude that the superior waveform for each FoM is different, and that the consideration of the trade-off relationship between the FoMs is required for waveform design.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.48-51
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• 2000

We proposed the new driving waveform which has changed the waveform of sustain division to improve luminous efficiency in plasma display panel. This sustain waveform is to add the ramp to the rectangular waveform, resulting in self-erasing discharge in the falling edge region. The proposed waveform has improved the luminous efficiency of 30％ even in low driving frequency(25kHz), whereas the conventional driving waveform using the self-erasing discharge can improve the luminous efficiency only in high driving frequency( >150kHz). Front the results of this paper, we hope that the variety study on frequency and duty ratio, ramp waveform will increase the luminous efficiency.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.39-42
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• 1988

In speech signal processing, it is necessary to estimate exactly the pitch. We propose a new algorithm which uses the correlation coefficient between the original and the repeated segmental waveform in the frame as a parameter in the pitch extraction. The correlation coefficient in the frame reflects the periodic component and the transient ratio of the waveform.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5906-5914
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• 2013

Recently in Korea, the policy is being proceeded to build a intergenerational housing on artificial ground of railroad site for utilizing rental house. Due to narrow space of rail road site, suitable method have to be developed such as micropiles which is known as a method of a fast construction. However, If micropile is used as foundations for the super structure, construction cost is increases compared with other pile. Consequently, new concept micropile proposed to improve both bearing capacity and cost efficiency of general micropile. New concept micropile consists of waveform cement grout surrounding tread bar that formed by grouting the soil layer with jet grouting method as control the grout pressure and flow. The micropile with waveform is expected to decrease the construction cost by cut down pile length of general micropile. This paper examined the behavior of the new concept micropile with waveform subjected to axial load using two-dimensional axisymmetric numerical analyses method. According to the numerical result, there will cost effectiveness as the pile displacement decreased despite the length of waveform micropile is down about 5% from a general micropile under the same loading condition. Also, the effect of skin friction force which mobilized from the waveform of micropile appeared at relatively soft ground.

• 전기의세계
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• v.30 no.1
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• pp.41-46
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• 1981

In the current source inverters (CSI), which are widely used recently in many applications, in order to reduce the harmonic contents in the output line current, twelve-step waveform is synthesized usually by a phase-shifted addition of the output currents of two single CSI's. In this paper a new method of synthesis of the 12-step current waveform is suggested which employes a main and a new auxiliary inverters having lower capacity, and thus is economically advantageous over the conventional scheme. DC-side commutation and energy rebond circuit as described in Part I are also employed in this proposed twelve-step CIS for effective commutation and high reliability. Experimental results are also given in oscillgrams.

• Nuclear Engineering and Technology
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• v.51 no.2
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• pp.432-438
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• 2019

In the study of nuclear structure, the fast timing technique can be used to measure the lifetime of excited states. In the paper, we have developed a new fast timing system, which is made up of two $LaBr_3:Ce$ detectors and a set of waveform sampling system. The sampling system based on domino ring sampler version 4 chip (DRS4) can digitize and store the waveform information of detector signal, with a smaller volume and higher timing accuracy, and the waveform data are performed by means of digital waveform analysis methods. The coincidence time resolution of the fast timing system for two annihilation 511 keV ${\gamma}$ photon is 200ps (FWHM), the energy resolution is 3.5%@511 keV, and the energy linear response in the large dynamic range is perfect. Meanwhile, to verify the fast timing performance of the system, the $^{152}Gd-2_1^+$ state form ${\beta}^+$ decay of $^{152}Eu$ source is measured. The measured lifetime is $45.3({\pm}5.0)ps$, very close to the value of the National Nuclear Data Center (NNDC: $46.2({\pm}3.9)ps$). The experimental results indicate that the fast timing system is capable of measuring the lifetime of dozens of ps. Therefore, the system can be widely used in the research of the fast timing technology.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.511-514
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• 2004

ADS(Address Display period Separation) driving method has been considered to be the most appropriate driving technique for AC PDPs. However when the ADS driving method is applied to the high-resolution AC PDP, the required long addressing time often becomes a problem. In this paper, we present a new waveform for reducing the addressing time and for the stable addressing discharge. In this new waveform, a wall charge acceleration pulse is applied to the common electrode right after 80us scan time. In this way, the charge generated by the addressing discharge is accelerated to the electrodes. Experiments using the wall charge acceleration pulse showed that we could stably address an AC PDP with the scan pulses having pulse width of 1 us

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2181-2183
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• 1997

In this paper, new photovoltaic system that has 3 step output voltage is proposed. This system use new PWM method named as equivalent area PWM. This method is based on the criterion of the calculation that each area of voltage pulses equals to the integrated value of each time shared division of the reference sinusodial waveform to make a PWM pulse. We applyed this method to 2 step inverter and 3 step inverter and analyzed waveform using FFT.