• Journal of Digital Convergence
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• v.11 no.5
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• pp.285-290
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• 2013

In a MPC coding using excitation source of voiced and unvoiced, it would be a distortion of speech waveform. This is caused by normalization of synthesis speech waveform of voiced in the process of restoration the multi-pulses of representation section. To solve this problem, this paper present a method of position compensation(PC-MPC) in a multi-pulses each pitch interval in order to reduce distortion of speech waveform. I was confirmed that the method can be synthesized close to the original speech waveform. And I evaluate the MPC and PC-MPC using multi-pulses position compensation method. As a result, $SNR_{seg}$ of PC-MPC was improved 0.4dB for female voice and 0.5dB for male voice respectively. Compared to the MPC, $SNR_{seg}$ of PC-MPC has been improved that I was able to control the distortion of the speech waveform finally. And so, I expect to be able to this method for cellular phone and smart phone using excitation source of low bit rate.

• Journal of Digital Convergence
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• v.12 no.6
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• pp.271-276
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• 2014

In a speech coding system using excitation source of voiced and unvoiced, it would be involved a distortion of speech quality in case coexist with a voiced and unvoiced consonants in a frame. In this paper, I propose a method of 8kbps Multi-Pulse Speech Coding(FBD-MPC: Frequency Band Division MPC) by using TSIUVC(Transition Segment Including Unvoiced Consonant) searching, extraction and approximation-synthesis method in a frequency domain. I evaluate the 8kbps MPC and FBD-MPC. As a result, SNRseg of FBD-MPC was improved 0.5dB for female voice and 0.2dB for male voice respectively. Compared to the MPC, SNRseg of FBD-MPC has been improved that I was able to control the distortion of the speech waveform finally. And so, I expect to be able to this method for cellular phone and smart phone using excitation source of low bit rate.

• Bulletin of the Korean Space Science Society
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• 1993.10a
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• pp.15-15
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• 1993

Revised Yale Isochrone(Green et al, 1987)과 Lee의 HB simulation data(LEE '||'&'||' Demarque 1990)을 이용하여 Park이 만든 CMD simulation program(Park 1983).에 쌍성을 첨가하면 CMD에 어느 정도의 영향을 나타내게 되는가를 조사하였다. MS, SGB와 RGB는 큰 변화가 없었으나, HB에서는 많은 변화를 나타내었다. 193919 S02401193919 ^x We have observed the emission of HC3N J= 4-3, 5-4 10-9 and 12-11 transitions toward the Sgr B2 central region in an area of 150"XISO" with resolutions of16"-48". The intensities and central velocities of line profiles show significant variations with positions. In contrast to the in tensities of the low J-level transitions which gradually increase from the central source toward the outside region the HC3N emission of the high J-level transition become stronger toward the central radio continuum source MO5. Systematic chainge in the radial velocity of each line profile occurs along north-south direction there are a few peaks in most line profiles, and these indicate that there not multiple velocity components along the line of sight. Distributions of excitation temperah at and column density which were estimated from the excitation calculations show the existence of a small(IxEpc),hot(Tex> SOK) core which contains two tempegatlue peaks at -15" east and north of MDS. The column density of HCaN is (1-3):n1014cm-2. Column density at distant position from MD5 is larger than that in the (:entral region. We have deduced that this hot-core has a mass of 10sR1 which i:s about an order of magnitude larger those obtained by previous studies.previous studies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.4119-4124
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• 2011

In a MPC coding using excitation source of voiced and unvoiced, it would be a distortion of speech waveform in case of increasing or decreasing of speech signal amplitude in a frame. This is caused by normalization of synthesis speech signal in the process of restoration the multi-pulses of representation section. To solve this problem, this paper present a method of amplitude compensation(AC-MPC) in a multi-pulses each pitch interval in order to reduce distortion of speech waveform. I was confirmed that the method can be synthesized close to the original speech waveform. And I evaluate the MPC and AC-MPC using amplitude compensation method. As a result, SNRseg of AC-MPC was improved 0.7dB for female voice and 0.7dB for male voice respectively. Compared to the MPC, SNRseg of AC-MPC has been improved that I was able to control the distortion of the speech waveform finally. And so, I expect to be able to this method for cellular phone and smart phone using excitation source of low bit rate.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.4
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• pp.175-179
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• 2001

The switched reluctance drive exhibits higher levels of vibration and acoustic noise than that of most competing drives. The main source of vibration in the switched reluctance drive is generated by rapid change of radial force when phase current is extinguished by commutation action. A new excitation strategy for a Switched Reluctance Motor with Auxiliary Winding (SRMAW) is described and tested. This scheme has auxiliary winding with one diode which is sound to all th poles in one winding. In this scheme, auxiliary winding is used to reduce magnetic stress during commutations. The abrupt change of a phase excitation produces mechanical stresses and it results in vibration and noise. The acoustic noise is reduced remarkably through 2-stage commutation. The operational principle and a characteristic comparison to that of the conventional SRM show that this scheme has some advantages including noise reduction as well as high efficiency drive.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.19-26
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• 2006

The ccrf-discharge has in comparison with the hollow-cathode discharge and DC-discharge some advantages: Simple design of the tube and homogeneous plasma. The ccrf-discharge was researched with the goal, to use on the excitation of the gas laser. In this work a rf-exciting system was planned and developed. With it a homogeneous discharge was produced in the cw operation. To supply the rf-power with the frequency 13.56[MHz] effectively in the discharge, laser tube were used with inner diameter of 5[mm] and the specially developed rf-electrodes. A matching circuit was composed also. Thereby the impedance of the discharge tube was adjusted to the 50[$\Omega$] output resistance of the rf-source.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.1000-1004
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• 2008

As performance of medical air compressor improve, the problem of noise increased. Noise is very important to medical air compressor because most of this installed inside of building. The main goal of this paper is show TPA (Transfer Path Analysis) result for contribution analysis using PAK system. Generally, the conventional TPA method consists of two steps. First, transfer functions between output sound and sources are measured by excitation experiment. Second, transferred sound in each transfer path is generated by multiplying the transfer function and the sound source signal. Then, if the output sound synthesized from all transferred sounds doesn't give good agreement with the measured output sound (i.e., the accuracies of the transfer functions are low), setting a suitable countermeasure guideline becomes difficult. For obtaining highly accurate transfer functions, eliminating correlations among transfer functions and noise included in the measured data are necessary. In the new method with PAK system, the vibration acceleration and sound signals around the sound sources and the output sound were measured simultaneously to obtain the transfer functions when compressor was operating. By applying PAK system, a highly accurate and efficient transfer path analysis method was developed that does not require an excitation experiment.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.2
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• pp.9-15
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• 2011

Fluorescent whitening agent (FWA) is a widely used chemical in paper industry, but a systematic and scientific method on FWA analysis has not been established. We performed the basic researches on the fluorescence analysis of FWA. The fluorescence of FWA was investigated using a spectrofluorometer and a spectrophotometer. When FWA solution was analyzed using the spectrofluorometer, we found that the peak wavelength of the fluorescence emission was about 440 nm and that of the fluorescence excitation was about 370 nm irrespective of FWA types. Papers dyed with an internal FWA were prepared in a laboratory and the reflectance and the fluorescence index were measured using the spectrophotometer. It was confirmed that the optimum peak wavelength of the reflectance was 440 nm and the fluorescence index calculated from the CIE whiteness with and without UV light under a light source D65 was the best indicator to measure the fluorescence of FWAs exiting in papers.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.5
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• pp.129-137
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• 2000

The powertrain is an important factor for the interior and exterior noise behavior of the vehicle Thus, the noise vibration and harshness(NVH) behavior of an engine is becoming a major target of the powertrain development. This paper describes the analyses with the aim to reduce the vibration and noise of an advanced inline 4-cylinder diesel engine block by use of CAE methods. The characteristics of an engine block as a main excitation source of car interior noise is studied. Particularly, The effect of balance shaft to reduce the 2nd order engine excitation force is calculated by forced vibration and radiated noise analysis. The engine exitation forces are obtained under real operating conditions. It is shown that the reduction of vibration and noise level by adapting blancing shaft is well predicted and rediated noise is directly related to the surface velocity of engine block.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.73-78
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• 2004

A highly sensitive detecting method has been developed for determining part per billion of sulfur in $H_2S$/Ar plasma. The method is based on the excitation of Ar/$H_2S\;or\;Ar/H_2S/O_2$ mixture in hollow cathode glow discharge sustained by radiofrequency (RF) or 60 Hz AC power and the spectroscopic measurement of the intensity of emission lines from electronically excited $S_2^*\;or\;SO_2^*$ species, respectively. The RF or AC power needed for the excitation did not exceed 30 W at a gas pressure maintained at several mbar. The emission intensity from the $SO_2^*$ species showed excellent linear response to the sulfur concentration ranging from 5 ppbv, which correspond to S/N = 5, to 500 ppbv. But the intensity from the $S_2^*$ species showed a linear response to the $H_2S$ only at low flow rate under 20 sccm (mL/min) of the sample gas. Separate experiments using $SO_2$ gas as the source of sulfur demonstrated that the presence of $O_2$ in the argon plasma is essential for obtaining prominent $SO_2^*$ emission lines.