• 대한전자공학회논문지SP
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• 제42권4호
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• pp.103-110
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• 2005

음성 데이터베이스는 TTS 시스템에서 가장 중요한 요소 중의 하나이다. 특히, 내장형 TTS 시스템에서는 서버형 TTS 시스템에서보다 좀 더 작은 데이터베이스를 필요로 한다. 이러한 이유로, 음성합성 데이터의 압축과 통계적 축소과정의 비중은 내장형 TTS 시스템에서 아주 중요한 항목이라고 말할 수 있다. 그러나 이러한 압축과 통계적 축소과정은 합성음질의 저하를 유발시킨다. 본 논문에서는 고품질 내장형 TTS 시스템에서의 데이터 구축방법을 제안하며, MOS 테스트를 통한 합성음질을 검증한다.

• Journal of information and communication convergence engineering
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• 제1권3호
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• pp.163-168
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• 2003

This paper presents a cascade multilevel PWM rectifier without the isolation transformers for energy build-up at each inverter modules. The features and advantages of the proposed PWM rectifier can be summarized as follows; I) It realizes the high power high voltage AC/DC power conversion, 2) It uses no transformer which is bulky and heavy, 3) It has hybrid structure so that switching devices can be effectively utilized, 4) It produces high quality AC current even in high power high voltage applications, 5) The input power factor remains unity by simple modulation index control. The multilevel rectifier is analyzed by using the circuit DQ transformation whereby the characteristics and control equations are obtained. Finally, it will be shown that the system simulation reveals the validity of analyses.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.576-580
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• 2001

This paper presents a casca multilevel PWM rectifier without the isolation transformers for energy build-up at each inverter modules; The features and advantages of the proposed PWM rectifier can be summarized as follows; 1) It realizes the high power high voltage AC/DC power conversion, 2) It uses no transformer which is bulky and heavy, 3) It has hybrid structure so that switching devices can be effectively utilized, 4) It produces high quality AC current even in high power high voltage applications, 5) The input power factor remains unity by simple modulation index control. The multilevel rectifier is analyzed by using the circuit DQ transformation whereby the characteristics and control equations are obtained. Finally, it will be shown that the system simulation reveals the validity of analyses

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2010년도 춘계학술대회
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• pp.16-23
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• 2010

This research analyzed about inconsistence and cause of the audit result on national defense quality management system in certification company. Direction of research analyzes corelation with distribution by items at national defense quality management system standard by Investigated number and occurrence of examination report slight and critical incongruity on 2008 and 2009. Study finding slight and critical incongruity happened to first examination average 10.2 items, renewal examination average 7.0 items. By incongruity occurrence appeared high in item that there are a lot of examination item shares of standard requirement, it was studied by correlative thing between the examination with standard. Factor of incongruity occurrence was proved to comprehension insufficiency for quality management system, quality procedure insufficiency, didn't fulfil proceedings, business was unripe. In this papers, we contribute to propose direction for improvement of national defense quality management system comprehensive faculty elevation and national defense quality certification in this treatise.

• 한국전자파학회논문지
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• 제15권5호
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• pp.509-516
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• 2004

Cu 및 BCB 공정을 사용하여 고성능 RF 수동회로를 실리콘 기판 상에 구현하는 RF 수동 집적회로 공정을 개발하였다. 이러한 기술은 개별 수동소자를 통한 모듈 구현방식보다 훨씬 작고 저렴하며 우수한 성능의 RF모듈을 구현할 수 있게 하였다. 개발된 실리콘 수동 집적회로 공정으로 제작된 내경 225 um, 회전수 2.5의 인덕터는 2.7 nH의 인덕턴스를 가지며 1 ㎓ 이상에서 30 이상의 품질계수를 가지는 것으로 측정되었다. 또한 개발된 인덕터를 사용하여 WLCSP(Wafer Level Chip Scale Package) 형태의 수동회로를 제작하였다. 제작된 저역 여파기는 2차 고조파 억제를 위해 인덕터 내경 안에 병렬공진용 커패시터를 삽입하였고 2.45 ㎓에서 0.5 ㏈ 이하의 삽입손실을 보였다. 그리고 고역 여파기와 저역 여파기 구조를 가지는 발룬 회로는 2.45 ㎓에서 0.5 ㏈ 이하의 삽입손실과 182도의 출력 단자간 위상 차이를 보여주었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1250-1251
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• 2008

In this study, the dielectric ceramics with low loss were investigated for high frequency application. All sample of the $Ba_5M_4O_{15}$ (M=Ta, Nb) ceramics were prepared by the conventional mixed oxide method and sintered at $1325{\sim}1575^{\circ}C$. The bulk density and dielectric constant of the $Ba_5Ta_4O_{15}$ ceramics were increased continuously with increasing of sintering temperature. The quality factor was increased in the sintering temperature of $1375{\sim}1475^{\circ}C$ but decreased at the temperature above 1475$^{\circ}C$. In the case of $Ba_5Nb_4O_{15}$ ceramics, the bulk density, dielectric constant and quality factor were increased with sintering temperature but decreased above temperature of 1400$^{\circ}C$. The dielectric constant, quality factor and temperature coefficient of the resonant frequency (TCRF) of the $Ba_5Ta_4O_{15}$ and $Ba_5Nb_4O_{15}$ ceramics, sintered at 1475$^{\circ}C$ and 1400$^{\circ}C$, were 25.15, 53105 GHz, -3.06 ppm/$^{\circ}C$ and 39.55, 28052 GHz, 5.7 ppm/$^{\circ}C$, respectively.

• E2M - 전기 전자와 첨단 소재
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• 제10권6호
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• pp.533-540
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• 1997

The microwave dielectric properties of ((P $b_{1-x}$ C $a_{x}$)Zr $O_3$ and (P $b_{0.63}$,C $a_{0.37-x}$ $M_{x}$)Zr $O_3$(M=Mg,Sr) ceramics were investigated. In (P $b_{1-x}$ C $a_{x}$)Zr $O_3$ (X=0.33~0.40) ceramics, high quality factor and small temperature coefficient of resonant frequency were obtain in (P $b_{0.63}$C $a_{0.37}$)Zr $O_3$with perovskite structure. In the case of (P $b_{0.63}$C $a_{0.37-x}$M $g_{x}$)Zr $O_3$ dielectric constant temperature coefficient of resonant frequency increased and quality factor decreased due to increase of polarization of A-O bonding. When replacing Ca ion with Sr ion with large ion radius, polarization decreased with increased of bonding length and thus dielectric constant and temperature coefficient of resonant frequency decreased.decreased.creased.

• 한국소음진동공학회논문집
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• 제27권1호
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• pp.100-106
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• 2017

Sound quality engineering in automobile noise applications has become more and more important under the current quiet driving condition because various noise components masked under high noise level can be audible in quieter driving situation. Many researches have been carried out for subjective and objective assessments on automobile sounds and noises. In particular, the interior sound quality has been one of research fields that can give high-quality feature to automobile products. Although many works related to the interior sound quality have been progressed or completed in foreign countries, limited research results are presented in the country. In the study, subjective assessments are first performed with 20 subjects to select perceptual adjectives suitable to the assessment of car interior noises during acceleration. The selected perceptual adjectives are employed as the assessment scales to evaluate the acceleration noises in questionnaire procedures using 35 subjects, for which several noises are created through digital filtering of the acceleration noises measured. Mean values and standard deviations for subjective assessment scores obtained by the questionnaire procedures are calculated and their reliability are also verified. Finally, various statistical analyses such as the correlation analysis and the factor analysis are carried out to reveal the interrelationship between the assessment scales and the spectrum components of the acceleration noises.

• 한국초전도ㆍ저온공학회논문지
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• 제16권4호
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• pp.26-30
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• 2014

We investigate the upper critical field anisotropy ${\Gamma}_H$ and the magnetic penetration depth anisotropy ${\Gamma}_{\lambda}$ of a high-quality $FeSe_{1-x}$ single crystal using angular dependent resistivity and torque magnetometry up to 14 T. High quality single crystals of $FeSe_{1-x}$ were successfully grown using $KCl-AlCl_3$ flux method, which shows a sharp superconducting transition at $T_C{\sim}9K$ and a high residual resistivity ratio of ~ 25. We found that the anisotropy ${\Gamma}_H$ near $T_C$ is a factor of two larger than found in the poor-quality crystals, indicating anisotropic 3D superconductivity of $FeSe_{1-x}$. Similar to the 1111-type Fe pnictides, the anisotropies ${\Gamma}_{\lambda}$ and ${\Gamma}_H$ show distinct temperature dependence; ${\Gamma}_H$ decreases but ${\Gamma}_{\lambda}$ increases with lowering temperature. These behaviors can be attributed to multi-band superconductivity, but different from the case of $MgB_2$. Our findings suggest that the opposite temperature dependence of ${\Gamma}_{\lambda}$ and ${\Gamma}_H$ is the common properties of Fe-based superconductors.

• 환경위생공학
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• 제22권4호
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• pp.87-104
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• 2007

The objective of this study is to estimate the load of pollutants caused from the forest area among non-point pollutants within the Juam lake. The surveyed forest area was classified into broad-leaved, conifer, mixed and herbage area by forest tree type. Water quality and flux were investigated under rainfall and non-rainfall, respectively. Then, pollutant loading was evaluated by using the values of unit pollutant loading factor of each point and area of forest zone. Water quality analysis results of runoff by forest tree types were as follows. - Annual BOD, $COD_{Mn}\;and\;COD_{Cr}$ concentration of runoff in conifer area was high, and particle and biological recalcitrant compounds were flowed highly. - SS, T-N and T-P concentration was high in runoff from broad-leaved area, and biological degradable compounds was flowed. - Water quality of water from valley was maintained good under non-rainfall and could be utilized as fresh drinking water. Through water quality standard investigation, a countermeasure establishment was necessary to secure a good quality of drinking water - BOD, $COD_{Mn},\;and\;COD_{Cr}$ concentration of Bo-sung river was higher 1.5 times than other 2 streams, and because of high T-N, and T-P concentration in Songgwang stream, the management for this was necessary.