• Title/Summary/Keyword: Edge Tone Edge

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Numerical Analysis of Flow-Induced Noise by Vortex-Edge Interaction (Vortex-Edge의 상호작용에 기인한 유동소음의 전산해석)

  • KANG HO-KEUN;KIM EUN-RA
    • Journal of Ocean Engineering and Technology
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    • v.18 no.5
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    • pp.15-21
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    • 2004
  • An edge tone is the discrete tone or narrow-band sound produced by an oscillating free shear layer, impinging on a rigid surface. In this paper, we present a 2-D edge tone to predict the frequency characteristics of the discrete oscillations of a jet-edge feedback cycle, using the finite difference lattice Boltzmann method (FDLBM). We use a modified version of the lattice BGK compressible fluid model, adding an additional term and allowing for longer time increments, compared to a conventional FDLBM, and also use a boundary fitted coordinates system. The jet is chosen long enough in order to guarantee the parabolic velocity profile of the jet at the outlet, and the edge consists of a wedge with an angle of ${\alpha}$ = 23. At a stand-off distance, the edge is inserted along the centerline of the jet, and a sinuous instability wave, with real frequency, is assumed to be created in the vicinity of the nozzle and propagates towards the downstream. We have succeeded in capturing very small pressure fluctuations, resulting from periodical oscillations of a jet around the edge. The pressure fluctuations propagate with the speed of sound. Its interaction with the wedge produces an non-rotational feedback field, which, near the nozzle exit, is a periodic transverse flow, producing the singularities at the nozzle lips.

Numerical Investigation of Aerodynamic Sounds by Vortex-Edge Interaction (Vortex-Edge 의 상호작용에 의한 유동소음의 수치계산)

  • Kang, Ho-Keun;Kim, Jeong-Hwan;Kim, Yu-Taek;Lee, Young-Ho
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1915-1920
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    • 2004
  • An edge tone is the discrete tone or narrow-band sound produced by an oscillating free shear layer impinging on a rigid surface. In this paper we present a two-dimensional edge tone to predict the frequency characteristics of the discrete oscillations of a jet-edge feedback cycle by the finite difference lattice Boltzmann method. We use a new lattice BGK compressible fluid model that has an additional term and allow larger time increment comparing a conventional FDLB model, and also use a boundary fitted coordinates. The jet is chosen long enough in order to guarantee the parabolic velocity profile of the jet at the outlet, and the edge consists of a wedge with an angle of ${\alpha}=23^{\circ}$ . At a stand-off distance ${\omega}$ , the edge is inserted along the centreline of the jet, and a sinuous instability wave with real frequency f is assumed to be created in the vicinity of the nozzle and to propagate towards the downstream. We have succeeded in capturing very small pressure fluctuations result from periodically oscillation of jet around the edge. That pressure fluctuations propagate with the sound speed. Its interaction with the wedge produces an irrotational feedback field which, near the nozzle exit, is a periodic transverse flow producing the singularities at the nozzle lips.

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Korean Speaker's Edge Tone Patterns of English Conjunctive Utterances (한국인 학습자의 영어 접속사 발화에 나타난 가장자리성조 패턴)

  • Lee, Joo-Kyeong
    • Speech Sciences
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    • v.12 no.4
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    • pp.141-152
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    • 2005
  • This paper shows the tonal patterns of English conjunctive utterances produced by Korean speakers of English, presenting that Korean speakers realize either the H - phrase tone or the H% boundary tone at the phrase-final part of the conjunctive utterances. Based on Pierrehumbert & Hirschberg's (1990) claim that either H- or H% tone indicates that a phrase is related to the following one, Korean speakers seem to produce the satisfactory patterns of edge tones in conjunctive sentences. In the experiment, we made up conjunctive sentences including both coordinate conjunctions such as and, but, or, and so and subordinate conjunctions like if, when and though. We varied the stimuli according to the existence of a comma and the lengths of connecting words and phrases. We also divided the subjects into two levels of English proficiency based on their English written test scores to see if Korean speakers' performance ability of edge tones is related with their general competence of English. Results show that Korean speakers produced 84% of the H- phrase tone in intermediate phrases and H-L% and L-H% boundary tones in intonational phrases. Also, coordinate and subordinate conjunctions show little difference in their tonal contours, and the existence of a comma or the lengths of connecting words and phrases do not affect Korean speakers' production of the H- phrasal tone and the H% boundary tone. This may suggest that pitch accents, rather than edge tones, should be put more focus on in teaching English intonation in Korea as much work has already shown that Korean speakers have serious problem with producing pitch accents in speaking English.

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Fluid analysis of edge Tones at low Mach number using the finite difference lattice Boltzmann method (차분격자볼츠만법에 의한 저Mach수 영역 edge tone의 유체해석)

  • Kang H. K.;Kim J. H.;Kim Y. T.;Lee Y. H.
    • 한국전산유체공학회:학술대회논문집
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    • 2004.03a
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    • pp.113-118
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    • 2004
  • This paper presents a two-dimensional edge tone to predict the frequency characteristics of the discrete oscillations of a jet-edge feedback cycle by the finite difference lattice Boltzmann method (FDLBM). We use a new lattice BGK compressible fluid model that has an additional term and allow larger time increment comparing the conventional FDLBM, and also use a boundary fitted coordinates. The jet is chosen long enough in order to guarantee the parabolic velocity profile of the jet at the outlet, and the edge consists of a wedge with an angle of $\alpha=23^0$. At a stand-off distance $\omega$, the edge is inserted along the centreline of the jet, and a sinuous instability wave with real frequency f is assumed to be created in the vicinity of the nozzle and th propagate towards the downstream. We have succeeded in capturing very small pressure fluctuations result from periodically oscillation of jet around the edge. That pressure fluctuations propagate with the sound speed. Its interaction with the wedge produces an irrotational feedback field which, near the nozzle exit, is a periodic transverse flow producing the singularities at the nozzle lips. The lattice BGK model for compressible fluids is shown to be one of powerful tool for computing sound generation and propagation for a wide range of flows.

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Improved Algorithm of Sectional Tone Mapping for HDR Images (HDR 이미지를 위한 단면 톤 매핑 개선 알고리즘 구현)

  • Lee, Yong-Hwan;Kim, Heung-Jun
    • Journal of the Semiconductor & Display Technology
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    • v.20 no.2
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    • pp.137-140
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    • 2021
  • High dynamic range (HDR) technology has been drawing attention in the field of imaging and consumer entertainment. As tools for capturing and creating HDR contents, encoding, and transmission evolve to support HDR formats, various display capabilities are being developed and increased. Hence, there is need for remapping native HDR imagery for display on lower quality legacy standard dynamic range (SDR) displays. This operation is referred to as tone mapping. In this paper, we present a sectional tone mapping method by Lenzen, and expand upon a tone mapping approach to improve temporal stability while maintaining picture quality. Compared to the existing block-based sectional tone mapping, our method uses the edge awareness-based tone mapping. We estimate the performance of the objective metric on temporal flickering. The experimental result shows that the algorithm maintains a smoother relationship between the output luminance values, and this reveals success in reducing halos and improving temporal stability with adopted edge aware filtering.

Inverse halftoning Using Anisotropic diffusion and Edge map (비등방성 확산 필터와 에지맵을 이용한 역하프토닝)

  • 고기영;주동현;염동훈;김두영
    • Proceedings of the Korea Institute of Convergence Signal Processing
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    • 2000.12a
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    • pp.81-84
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    • 2000
  • Digital Halftoning convert a continuous-tone images to a binary images. Inverse halftoning addresses the problem of recovering a continuous image from a halftoned binary image. Simple low pass filtering can remove the high frequency noise but it also removes the edge information. Thus the edge information should be separated from the halftoning noise. As a result, the edge of result image is blurring. This paper present that we obtain continuous-tone-image which using Anisotropic diffusion filter. To reduce noise without blurring the edges of reconstructed image use edge map. The experimental results show that proposed method gives a higher PSNR and better subjective quality than conventional methods. As a result, the edge information of reconstructed image reduce blurring.

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Experimental study of boundary layer at the entrance of a cavity (공동 입구의 경계층에 관한 실험적 연구)

  • Jung Yong-Wun;Park Seung-O;Lee Duck-Joo
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.775-778
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    • 2002
  • In order to analyse the mechanism of a flow tone around a cavity, the correlations between the flow in the cavity and the boundary layer flow in front of the cavity are studied experimentally in this paper. The instability In the boundary layer forms the vortex at the front edge of the cavity and the flow tone is occurred by the vortex breakdown at the rear edge of the cavity Therefore, the boundary layer measurement is important in the cavity flow control. We measure the velocity of the boundary layer at the entrance of the cavity using hot-wire anemometry and the flow tone around the cavity by microphone. The boundary layer characteristic is changed by the various angle of the flap on the front edge of the cavity, while it is less influenced by the ratio of length and depth of the cavity.

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Edge Tones of English Conditional Clauses and an Intonational Contribution to Discourse Interpretation (영어 조건절의 경계억양과 담화해석에서 영어 억양의 역할)

  • Lee, Joo-Kyeong;Kong, Eun-Jong;Kim, Kee-Ho
    • Speech Sciences
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    • v.8 no.2
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    • pp.149-163
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    • 2001
  • This paper investigates the manner in which various. syntactic structures with a single meaning implement a consistent intonational pattern by examining English conditional clauses. In the phonetic experiment, we explore the edge tones in three different syntactic clauses which are semantically interpreted as a single conditional meaning (an if-clause, a clause with no if. and a clause with no if but followed by and) and compare them with the edge tone realized in a clause which is not interpreted as a conditional meaning. We also investigate the tonal differences resulting from the semantic difference between conditional and non-conditional meanings. That is, the conditional clauses expressed in three different syntactic structures show a consistent intonational pattern in their clausefinal boundaries; a rising contour (H- or H%) is realized at the edge of the intermediate phrases (ip) or intonational phrases (IP) in 89% of the if-clauses, 72% of the clauses with no if, and 79% of the clauses with no if but followed by and. On the other hand, 82% of the non-conditional clauses have a falling contour (L- or L-L%) in their final edge. Statistically, Chi-Square tests show that these percentages are all significantly higher, which suggests that a conditional meaning implements a consistent intonational pattern though it is expressed through different syntactic structures. Therefore, the result supports Bolinger's (1989) claim that intonation makes an important contribution to discourse interpretation.

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The Edge Enhanced Error Diffusion Using Local Characteristic Weights (국부적 특성 가중치를 이용한 에지 강조 오차 확산 방법)

  • 곽내정;윤태승;유성필;안재형
    • Proceedings of the IEEK Conference
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    • 2003.11a
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    • pp.381-384
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    • 2003
  • Among digital halftoning methods, error diffusion is a procedure for generating high quality bilevel images from continuous-tone images but blurs the edge information in the bilevel images. To solve the problem, we propose the edge enhanced error diffusion using the edge information of the original images. The edge enchanted weights is computed by adding local characteristic weights and input pixels multiplied a constant. Also, we combined the edge enhanced method with the adaptive error diffusion using human spatial and frequency perception characteristic. The performance of the proposed method is compared with conventional method by measuring the edge correlation. The halftoned images applied the proposed method get more fine quality due to the enchanced edge and better quality in halftoned image. And the detailed edge is preserved in the halftoned images by the proposed method.

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