• Title/Summary/Keyword: Acoustic Space

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Synthesis of 3D Sound Movement by Embedded DSP

  • Komata, Shinya;Sakamoto, Noriaki;Kobayashi, Wataru;Onoye, Takao;Shirakawa, Isao
    • Proceedings of the IEEK Conference
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    • 2002.07a
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    • pp.117-120
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    • 2002
  • A single DSP implementation of 3D sound movement is described. With the use of a realtime 3D acoustic image localization algorithm, an efficient approach is devised for synthesizing the 3D sound movement by interpolating only two parameters of "delay" and "gain". Based on this algorithm, the realtime 3D sound synthesis is performed by a commercially available 16-bit fixed-point DSP with computational labor of 65 MIPS and memory space of 9.6k words, which demonstrates that the algorithm call be used even for the mobile applications.

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Analysis of Korean Phonemes Using Multi-Dimentional Scaling Method (다차원 척도 구성법을 이용한 한국어 음소의 분석)

  • 권영욱;정현열
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.29B no.11
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    • pp.22-30
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    • 1992
  • Using Multi-Dimentional Scaling(MDS) method, this paper analyzes the differences of acoustic properties of Korean phonemes projected as distances on a plan space. The phonemes were extracted from mono-syllables frequently occurring in daily conversation. From the distances between vowels we found that the distances between vowels /∂/ and /w/, /o/ and /u/, and vowels /$\varepsilon$/ and /e/ were relatively too short separate automatically. From the analysis of consonants. we found short distances between 1) phonemes in each phoneme group, 2) nasals and liquid /r/ of work initial, 3) nasal /n,m/ and liquid /l/ of word finals. But nasals, liquids and plosives of word initials had enough distances to be separated from those of word finals in automatic recogniation.

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Comparison of mass operator methods considering test uncertainties

  • Olympio, K.R.;Blender, F.;Holz, M.;Kommer, A.;Vetter, R.
    • Advances in aircraft and spacecraft science
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    • v.5 no.2
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    • pp.277-294
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    • 2018
  • In the space industry, structures undergo several vibration and acoustic tests in order to verify their design and give confidence that they will survive the launch and other critical in-orbit dynamic scenarios. At component level, vibration tests are conducted with the aim to reach local or global interface loads without exceeding the design loads. So, it is often necessary to control and limit the input based on a load criterion. This means the test engineer should be able to assess the interface loads, even when load cannot be measured. This paper presents various approaches to evaluate interface loads using measured accelerations and by referring to mass operators. Various methods, from curve fitting techniques to finite element-based methods are presented. The methods are compared using signals with known imperfection to identify strengths and weaknesses of each mass operator definition.

A Comparative Study on the Power Spectrum of Three-Phase and Two-Phase RCD-PWM Scheme with Fixed Switching Frequency (고정 스위칭 주파수를 갖는 3상 및 2상 RCD-PWM의 파워 스펙트럼 비교)

  • Kim J.G.;Jung Y.G.;Lim Y.C.;Yang H.Y.;Wi S.O.
    • Proceedings of the KIPE Conference
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    • 2003.07a
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    • pp.308-312
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    • 2003
  • The objective of this paper is to investigate the power spectrum of a three-phase and a two-phase RCD (Random Pulse Centered Displacement) PWM scheme. The two-phase or three-phase pulses of RCD-PWM scheme are mutually center-aligned as in SVM(Space Vector Modulation), but the common pulse center is displaced randomly from the middle of the period. To verify the validity of the proposed two-phase RCD-PWM scheme, the power spectra of the output voltage, the d.c link current in the inverter drives and the radiated acoustic noise are experimentally investigated. And, the performance of the proposed two-phase RCD-PWM scheme was compared and discussed with the conventional three-phase RCD-PWM scheme.

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Turbulent Flow Analysis of a Circular Cylinder Using a Fractional Step Method with Compact Pade Discretization (Fractional Step 방법과 Compact Pade 차분화를 이용한 원형 실린더 주위의 난류 유동해석)

  • Chung S. H;Park K. S;Park W. G
    • Journal of computational fluids engineering
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    • v.8 no.3
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    • pp.50-55
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    • 2003
  • Recent numerical simulation has a tendency to require the higher-order accuracy in time, as well as in space. This tendency is more true in LES and acoustic noise simulation. In the present work, the accuracy of a Fractional step method, which is widely used in LES simulation, has been increased to the fourth-order accurate compact Pade discretization. To validate the present code, the flow-field past a cylinder was simulated and compared with experiment. A good agreement with experiment was achieved.

Phonon Dispersion and Specific Heat in FCC Structure (FCC구조에서 포논분산과 비열)

  • Chung, Jae-Dong;Lee, Kyung-Tae
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1207-1212
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    • 2004
  • A model for the phonon dispersion relationship for cubic zinc sulfide structure, for example SiC, is developed in terms of two unknown force constants. Born model that incorporates bond bending and bond stretching, is used for the force constants. The force constants are determined by fitting to experimental data. Using only the nearest-neighbor coupling results in $6{\times}6$ sized dynamic matrix. The eigenvalues of dynamics matrix for each wavenumber in 3-D ${\kappa}$ space correspond to frequencies, 3 for optical phonon and 3 for acoustic phonon, which is so-called dispersion relation (${\kappa}$-${\omega}$). The density of state is determined by counting the states for each frequency bin, and the properties such as specific heat and thermal conductivity can be obtained. The specific heat is estimated on this model and compared with experiment and other models, i.e. Debye model, Einstein model and combined Debye-Einstein model. In spite of the simple bond potential model, reasonable agreements are found.

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Acoustical design for remodeling of the Little theatre in Sejong Performing Arts Center (세종문화회관 소극장 리모델링을 위한 음향설계)

  • Jeon, Jin-Yong;Lee, Pyoung-Jik;Seo, Choon-Ki
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.991-996
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    • 2007
  • The Little theater in Sejong Performing Arts Center is a proscenium theater with 447 seats, which was built in 1978. The remodeling of the theater was decided in 2005 and acoustical design was conducted. Design guidelines were suggested based on the feasibility studies and acoustical measurement results. Target reverberation time was set at 1.2-1.6s with respect to the main performances. For the acoustical design, side balconies were added to increase the level of lateral reflections. Acoustic diffusers were designed and scattering coefficients were measured in a 1:10 reverberation chamber. From the results of computer simulation and a 1:10 scale model measurement, it was indicated that the new space will have RT of 1.2-1.6 s in middle frequencies when fully occupied.

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Study on the effects of space charge and conduction current by reversal of polarity (극성반전에 따른 공간전하 분포와 전도전류의 변화)

  • Gwak, Min-Woo;HwangBo, Seung;Chun, You-Jun;Shin, Hyun-June
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.1578-1579
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    • 2011
  • 본 논문에서는 고분자 절연체가 인가된 전압의 시간에 따라 변화하는 공간전하와 전도 전류의 영향에 대하여 조사를 하였다. 또한 극성반전에 따른 공간전하의 분포와 전도 전류에 변화에 대한 연구를 실시하였다. 기존의 공간전하 분포 측정법들은 주로 고분자 절연재료 내에서 공간전하분포의 측정만을 목표로 한 반면에 공간전하 측정법 중의 하나인 PEA(Pulsed Electro-Acoustic method)을 개선시켜 공간전하와 전도전류의 동시 측정을 가능하게 하였다. 개선된 PEA법은 시간변화에 따른 공간전하와 전기전도의 직접적인 상관관계와 미리 형성 되어 있는 공간전하가 전기전도 및 절연특성에 미치는 영향을 직접적으로 분석할 수 있는 장점을 가지고 있다. 이러한 공간전하와 전류의 동시 측정법을 이용하여 연구하였다.

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A Study on Musical Expression in the Monastery of La Tourette (라 뚜레뜨 수도원에서 나타난 음악적 표현에 관한 연구)

  • 김영희
    • Korean Institute of Interior Design Journal
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    • v.13 no.3
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    • pp.112-119
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    • 2004
  • The purpose of this study is to grasp musical expression in the Monastery of La Tourette, an architectural work produced by an architect, Le Corbusier and a musician, Iannis Xenakis based on a musical piece, Metastasis. The results of the study on musical expression in the Monastery of La Tourette, which was done through analysis of correlation in expression between architecture and music, and spatial characteristics of this monastery, are as follows: First, in modern architecture and music, the expression of the space-time continuum concept is emphasized. Second, the architectural characteristics in this monastery that constitute musical expression are the Modular, confliction and fluidity in composition, plastic (acoustic) shape and symbolic shape. Third, these architectural characteristics are found to be expressed as counterpoint, alteration, temporality, acoustics and canon of music.

Polarization and Charge Transport in Epoxy (에폭시의 분극 및 전하 이동)

  • Ahn, Jong-Hyun;Choi, Chung-Seog
    • Proceedings of the KIEE Conference
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    • 2008.09a
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    • pp.229-230
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    • 2008
  • The investigations included the measurements of volume currents and also internal space charges on epoxy samples of mm thicknesses. The current versus time relations were shown to correspond well with classical forms of dielectric response such as the Curie-von Schweidler model. After the time transient, near steady currents were extremely small and exhibited a significant temperature dependence, similar in relation to the Poole-Frenkel hoping transport model. Equivalent resistances were on the order of $10^{19}$ ohms and represent very weak charge transport. Electrically stimulated acoustic waves were used to quantify the small internal charges that would accumulate within the epoxy. There was a notable homocharge near both anode and cathode. The dielectric response and the internal charge were related to show a consistent model for charge transport within unfilled epoxy.

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