• Title/Summary/Keyword: SD-spectrum

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Biological and Physico-chemical Properties of Antifungal Cyclic Lipopeptides Produced by Pseudomonas cepacia Strains (Pseudomonas cepacia 균주가 생산하는 항진균성 Cyclic Lipopeptide의 생물학적 및 물리 화학적 특성)

  • Kim, Sung-Ho;Lee, Min-Woong
    • The Korean Journal of Mycology
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    • v.24 no.4 s.79
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    • pp.310-321
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    • 1996
  • Five strains AF027, AF069, AF2001, AF2011 and SD02 of Pseudomonas cepacia were isolated from soil, and the antifungal cyclic lipopeptides(CLP) i.e, CLP027A, CLP069A, Cepacidine A, CLP2011A and CLP02A were produced from each strains, respectively. Nitrogen and carbon sources in media were proved to be important factors for the production of CLP and among them, polypeptone-S, glucose and fructose were the most effective. It appeared that compounds CLP027A and CLP069A were identical with Cepacidine A and Xylocandine A, respectively. contain aspartic acid as amino acid component, are differentiated from Xylocandine A containing asparagine. Although molecular weight, amino acid composition and UV spectrum of CLP2011A and CLP02A are same with those of Cepacidine A, it is postulated that these compounds are not identical with Cepacidine A when the antifungal spectra and antifungal activity were compared to those of Cepacidine A.

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Analysis of Characteristics of Horizontal Response Spectrum of Velocity Ground Motions from 5 Macro Earthquakes (5개 중규모 지진의 속도 관측자료를 이용한 수평 응답스펙트럼 특성 분석)

  • Kim, Jun-Kyoung
    • Tunnel and Underground Space
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    • v.21 no.6
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    • pp.471-479
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    • 2011
  • The velocity horizontal response spectra using the observed ground motions from the recent 5 macro earthquakes, equal to or larger than 4.8 in magnitude, around Korean Peninsula were analysed and then were compared to the acceleration horizontal response spectra, seismic design response spectra (Reg Guide 1.60), applied to the domestic nuclear power plants, and finally the Korean Standard Design Response Spectrum for general structures and buildings. 102 velocity horizontal ground motions, including NS and EW components, were used for velocity horizontal response spectra and then normalized with respect to the peak velocity value of each ground motion. First, the results showed that velocity horizontal response spectra have larger values at the range of medium natural period, but acceleration horizontal response spectra have larger values at the range of short natural periods. Secondly, the results also showed that velocity horizontal response spectra exceed Reg. Guide 1.60 for longer natural periods bands less than 6-7 Hz. Finally, the results were also compared to the Korean Standard Response Spectrum for the 3 different soil types(SC, SD, and SE soil type) and showed that velocity horizontal response spectra revealed much higher values for the frequency bands below 1.5(SC), 2.0(SD), and 3.0(SE) seconds, respectively, than the Korean Standard Response Spectrum. The results suggest that the fact that acceleration, velocity, and displacement horizontal response spectra have larger values at the range of short, medium, and long natural periods, respectively, can be applied consistently to those form domestic ground motion, especially, the velocity ground motion. Information on response spectrum at such medium range periods can be very important since the domestic design of buildings and structures emphasizes recently medium and long natural periods than short one due to increased super high-rise buildings.

Subjective Timbre Space of 45 Modified Violin Tones

  • Ahn, Chul-Yong;Pang, Hee-Suk;Sung, Koeng-Mo
    • The Journal of the Acoustical Society of Korea
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    • v.19 no.1E
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    • pp.38-42
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    • 2000
  • In this paper we studied the reduced subjective timbre space of time-varying tones as well as steady state tones. 45 modified test tones were constructed from the original violin tone in consideration of 4 physical factors: spectrum envelope, inharmonicity, time-varying spectrum and time reversal. The semantic differential (SD) method was used in the listening test. According to the factor analysis, the adjectives can be factorized into 4 groups. The first factor is characterized by the adjectives, 'free', 'broad', 'deep', 'rich', 'strong' and 'reverberant', the second by 'tenor', 'clear', 'bright', 'light' and 'sharp', the third by 'easy', 'smooth', and 'solid', the fourth by 'warm' and 'full'. The first factor, 'richness', seems to be dependent upon the time-varying characteristic of a tone. The second factor, 'sharpness', is shown to play an important role in a time-varying tone as well as in a steady state tone.

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Spectrum Filter Algorithm based on Acoustic Model (음향학적 모델에 의한 스펙트럼 필터 알고리즘)

  • Choi, Jae-seung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.10a
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    • pp.770-772
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    • 2016
  • 본 논문에서는 음성신호처리 시스템에 유용하게 사용되는 음성신호의 특징 파라미터를 출력하는 스펙트럼 필터모델을 사용하여, 배경잡음 환경 하에서 음성신호 중의 잡음을 제거하는 알고리즘을 제안한다. 따라서 본 논문에서는 배경잡음을 제거할 때 고려해야 할 인간의 청각특성이 포함된 음성의 진폭 스펙트럼에 의한 청각필터의 특성을 도입한다. 본 논문의 실험에서 사용한 성능평가의 방법으로는 음절 명료도의 테스트에 적합한 주관적인 평가인 주파수 영역에서의 스펙트럼 왜곡률(Spectral Distortion, SD)을 사용하여 실험결과를 비교하고 고찰한다.

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A Study on an Improvement of the Performance by Spectrum Analysis with Variable Window in CELP Vocoder (CELP 부호화기에서 가변 윈도우 스펙트럼 분석에 의한 성능 향상에 관한 연구)

  • Min So-Yeon;Kim Eun-Hwan;Bae Myung-Jin
    • Journal of the Korea Society of Computer and Information
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    • v.10 no.6 s.38
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    • pp.233-238
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    • 2005
  • In general CELP(Code Excited Linear Prediction) type vocoders provide good speech qualify around 4.8kbps. Among them, G.723.1 developed for Internet Phone and video-conferencing includes two vocoders, 5.3kbps ACELP(Algebraic-CELP) and 6.3kbps MP-MLQ(Multi-Pulse Maximum Likelihood Quantization) In order to improve the speech qualify in CELP vocoder, in this paper. we proposed a new spectrum analysis algorithm with variable window In CELP vocoder, the spectrum of the synthesised speech signal is distorted because the fixed size windows is used for spectrum analysis. So we have measured the spectral leakage and in order to minimize the spectral leakage have adjusted the window size. Applying this method G.723.1 ACELP, we can got SD(Spectral Distortion) reduction 0.084(dB), residual energy reduction 6.3$\%$ and MOS(Mean Opinion Score) improvement 0.1.

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A Simple Phase Interpolator based Spread Spectrum Clock Generator Technique (간단한 위상 보간기 기반의 스프레드 스펙트럼 클락 발생 기술)

  • Lee, Kyoung-Rok;You, Jae-Hee;Kim, Jong-Sun
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.47 no.10
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    • pp.7-13
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    • 2010
  • A compact phase interpolator (PI) based spread spectrum clock generator (SSCG) for electromagnetic interference (EMI) reduction is presented. The proposed SSCG utilizes a digitally controlled phase interpolation technique to achieve triangular frequency modulation with less design complexity and small power and area overhead. The novel SSCG can generate the system clock with a programmable center-spread spectrum range of up to +/- 2 % at 200 MHz, while maintaining the clock duty cycle ratio without distortions. The PI-based SSCG has been designed and evaluated in 0.18-um 1.8-V CMOS technology, which consumes about 5.0 mW at 200MHz and occupies a chip size of $0.092mm^2$ including a DLL.

Evaluation of pulse effect on frequency content of ground motions and definition of a new characteristic period

  • Yaghmaei-Sabegh, Saman
    • Earthquakes and Structures
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    • v.20 no.4
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    • pp.457-471
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    • 2021
  • This study aims at providing a simple and effective methodology to define a meaningful characteristic period for special class of earthquake records named "pulse-like ground motions". In the proposed method, continuous wavelet transform is employed to extract the large pulse of ground motions. Then, Fourier amplitude spectra obtained from the original ground motion and the residual motion is simply compared. This comparison permits to define a threshold pulse-period (Tp∗) as the threshold period above which the pulse component has negligible contributions to the Fourier amplitude spectrum. The effect of pulse on frequency content of motions was discussed on the light of this definition. The advantage and superior features of the new definition were related to the inelastic displacement ratio (IDR) for single-degree-of-freedom systems with period equal to one half of the threshold period. Analyses performed for the proposed period at three ductility levels u=2,4,6 were compared with the results obtained at half of pulse period derived from wavelet analysis, peak-point method and the peak of product of the velocity and the displacement response spectra (Sv x Sd). According to the results, pulse effects on inelastic displacement ratio seem to be more important when $\frac{T_p^*}{T}=2$ (T is the fundamental vibration period of system). The results showed that utilizing of the proposed definition could facilitate an enhanced understanding of pulse-like records features.

Comparison Between the Facet Reflectivities of Buried Channel Waveguides and Those of Ridge Waveguides Using the Angular Spectrum Method (Angular spectrum 방법을 사용하여 구한 buried channel 도파로와 ridge 도파로의 단면 반사율 비교)

  • Kim, Sang-Taek;Kim, Dong-Hu;Kim, Bu-Gyun;Yu, Myeong-Sik
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.38 no.9
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    • pp.634-642
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    • 2001
  • We calculate the facet reflectivity of buried channel waveguides and ridge waveguides as a function of the waveguide width for various thicknesses using the angular spectrum method and the two dimensional field profiles obtained by the variational method (VM) and the effective index method (EIM). The variation of the reflectivity of buried channel waveguides as a function of the waveguide width is large, while that of ridge waveguides is very small. The accuracy of the field profiles necessary for the calculation of the facet reflectivity using the angular spectrum method greatly affects that of the facet reflectivity. The difference between the exact reflectivity and that using EIM increases as the waveguide width and thickness decreases due to the inaccuracy of the field profiles obtained by EIM. However, the difference between the exact reflectivity and that using VM is smaller than that using EIM regardless of waveguide width and thickness. The difference between the facet reflectivities u sing EIM and VM is small in the area where the EIM works very well.

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A Study on the Evaluation of Piezoelectric Thin Film Characteristics in Composite Resonator Structure Using Resonance Spectrum Method (공진주파수 스펙트럼법을 이용한 Composite Resonator 구조에서 압전박막의 특성 평가에 대한 연구)

  • Choi Joon Young;Chang Dong Hoon;Kang Seong Jun;Yoon Yung Sup
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.42 no.1
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    • pp.9-17
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    • 2005
  • We studied the characteristics of impedance and electromechanical coupling coefficient in ZnO and AIN thin films by using resonance frequency spectrum method. The response peak of impedance decreased with the decrease of thickness of piezoelectrics, the number of mode of response peak decreased with the decrease of substrate thickness. An error of Kt² estimated from input Kt² increased as the thickness of piezoelectrics decreased and the thickness of substrate increased. Also, the error was increased in case of a large acoustic impedance of substrate. It was found that the composite resonator operating in optimized condition could be designed through the resonance frequency spectrum analysis of composited resonator consisted of piezoelectric thin film and substrate.

Spectrum Leakage Reduction using Time Scaling Window (시간축 스케일링 윈도우를 이용한 스펙트럼 누설 감소)

  • LEE HeeWon;NA DuckSu;BAE MyungJin
    • Proceedings of the Acoustical Society of Korea Conference
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    • spring
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    • pp.107-110
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    • 2000
  • 음성 신호는 시간에 따라 변하지만 일정 구간에서는 특성이 변하지 않는다고 가정하여 윈도우를 취해 단구간 분석을 한다. 이 때 윈도우의 적용은 필수적이다. 하지만 단구간 분석을 위해서 사용되는 윈도우에 의해 생기는 누설에너지 때문에 음성신호의 스펙트럼 정보가 왜곡되어 버린다. 본 논문에서는 스펙트럼 분석 시 발생되는 누설에너지를 최소화하는 방법을 제안하고자 한다. 음성신호에 고정된 크기의 rectangular Window를 취한 후 처음 샘플과 차이가 가장 작은 샘플을 프레임 크기의 3/4인 지점에서부터 검색하여 최소인 부분까지 시간 축 스케일링을 한 후 기존의 윈도우 크기와 같은 크기로 만든다. interpolation과 decimation을 조합하여 시간 축 스케일링을 한다. 이렇게 윈도우가 적용된 신호를 처리 후 위의 역 과정을 수행한다. 제안한 윈도우의 SNRseg는 rectangular window보다 평균 7.88dB 낮고, kaiser window보다 평균 1.65dB 높았다. 또한 제안한 윈도우의 SD는 rectangular window 보다 평균 $1.73dB^\2$ 낮았다.

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