• Title/Summary/Keyword: sound control

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Design and control of quiet zone (principle and example) (조용한 공간 만들기 (방법론과 예))

  • Kim, Yang-Han;Yun, Du-Byeong;Nam, Gyeong-Uk
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.565-570
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    • 2000
  • In order to make a quiet zone, one can consider methods to generate a secondary sound field that cancels a primary sound field. Active noise control (ANC) is one of the kinds. This paper mainly deals with the issues on determining the optimal positions of control sources and sensors for making a desired quiet zone. The issues address the reason why the positions are important, how the positions are optimized, and what the measure on the optimal positions is in an uncertain sound field. It is also shown that a power control is applicable to a specific uncertain sound field. In addition, this paper shows that a control material method, which passively changes a boundary condition, is essentially found to be on the same road of ANC.

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A method of Shaped Sound Focusing Using Multiple Monopole Sources: Hollow Cylinder shape (다수의 단극 음원들을 이용한 속이 빈 실린더 형상의 응향 위치 에너지 집적공간 형성방법)

  • Park, Jin-Young;Kim, Yang-Hann
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.537-540
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    • 2005
  • Shaped Sound Focusing is defined as the generation of acoustically bright zone with a certain shape in space using multiple sources. The acoustically bright zone is a spatially focused region with relatively high acoustic potential energy level. In view of the energy transfer, acoustic focusing using multiple sources is essential because acoustic energy is very small to use other type of energy. It can be done by taking optimization techniques which can be acoustic brigtness control and acoustic contrast control. But it has not been frequently concerned about several cases, so the case of hollow cylinder shaped sound focusing is adapted and there wi11 be arguments about available control variables and spatially controllable region in this case.

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Prediction Method of Control Valve Noise (잔향실을 이용한 콘트롤 밸브 소음 예측 방법)

  • 이용봉;윤병로;박경암;이두희;유선학
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.8
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    • pp.703-707
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    • 2002
  • This paper proposes new method for predicting sound power emitted from the control valve and piping system. The sound power level measurement method using the reverberation chamber is much easy to apply in the field compared to the method using the anechoic chamber. Measured sound power was used to determine the coefficients of the equation predicting sound power level. The noise prediction equation was developed at relative flow coefficient, 0.11. The sound power level predicted is in good agreement with the measured value. Proposed method can be used to express the noise characteristics of the control valves.

Sound Source Localization using HRTF database

  • Hwang, Sung-Mok;Park, Young-Jin;Park, Youn-Sik
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.751-755
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    • 2005
  • We propose a sound source localization method using the Head-Related-Transfer-Function (HRTF) to be implemented in a robot platform. In conventional localization methods, the location of a sound source is estimated from the time delays of wave fronts arriving in each microphone standing in an array formation in free-field. In case of a human head this corresponds to Interaural-Time-Delay (ITD) which is simply the time delay of incoming sound waves between the two ears. Although ITD is an excellent sound cue in stimulating a lateral perception on the horizontal plane, confusion is often raised when tracking the sound location from ITD alone because each sound source and its mirror image about the interaural axis share the same ITD. On the other hand, HRTFs associated with a dummy head microphone system or a robot platform with several microphones contain not only the information regarding proper time delays but also phase and magnitude distortions due to diffraction and scattering by the shading object such as the head and body of the platform. As a result, a set of HRTFs for any given platform provides a substantial amount of information as to the whereabouts of the source once proper analysis can be performed. In this study, we introduce new phase and magnitude criteria to be satisfied by a set of output signals from the microphones in order to find the sound source location in accordance with the HRTF database empirically obtained in an anechoic chamber with the given platform. The suggested method is verified through an experiment in a household environment and compared against the conventional method in performance.

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The Design of Intelligent Real Sound Play Flatform and Service Based-on User's Information (사용자 정보 기반 지능형 실감 사운드 재생 플랫폼 및 서비스 구현)

  • Jung, Jong-Jin;Lim, Tae-Beom;Lee, Seok-Pil
    • IEMEK Journal of Embedded Systems and Applications
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    • v.6 no.3
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    • pp.174-182
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    • 2011
  • Conventional home audio system (e.g. AV Receiver, CD Player etc) has a various functionality of audio play, channel mixing, but the remote controller of these audio players is too complex, difficult for user to manage them effectively. Users want to use these functionalities with more easy, comprehensible way. In this study, "intelligent real-sound presentation technology" that support high quality, realistic audio and the "design of complex information and controller of real sound using intelligent real sound play and control interface" will be introduced. So user can actively, realistically enjoy and play real sound based on user's preference, emotion and circumstance, instead of user's passive service.

Automatic control of experimental apparatus for sound's directivity measurement direction acoustic wave (소리의 방향성 측정을 위한 실험기기의 자동제어)

  • Jarang, Sun-Suck;Ko, Jae-Ha;Lee, Je-Hyeong
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.591-594
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    • 2004
  • The directivity of the sound pressure increases the sensitivity of the incoming sound from specific directions. The directivity measurement of the sound pressure is usually done in an anechoic room using a steping motor. In this paper a replaceable anechoic chamber was designed for the acoustic directivity pattern measurement. Electrical equipments were interfaced with a PC for experiment automatic control. Some comparative results are shown in the result.

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Active Structural Acoustic Control for Reduction of Radiated Sound from Structure (구조물에서 방사되는 소음을 저감하기 위한 능동구조음향제어)

  • O, Jae-Eung;Hong, Jin-Seok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.9
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    • pp.1410-1415
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    • 2001
  • Active control of sound radiation from a vibrating rectangular plate by a steady-state harmonic point force disturbance is experimentally studied. Structural excitation is achieved by two piezoceramic actuators mounted on the panel. Two accelerometers are implemented as error sensors. Estimated radiated sound signals using vibro-acoustic path transfer function are used as error signals. The vibro-acoustic path transfer function represents system between accelerometers and microphones. The approach is based on a multi-channel filtered-x LMS algorithm. The results shows that attenuation of sound levels of 11dB, 10dB is achieved.

Actively controlled sound field of upper sections attached to noise harriers (방음벽 상단 소음의 회절에 관한 능동제어)

  • Koh, Hyo-In;Moser, Michael
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.482-485
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    • 2004
  • On the basis of theoretical studies on the effect of the cylinders attached to semi-infinite screens, the tangential sound power-transport parallel to the surface of the attached cylinder is minimized by means of a secondary sound field, which is generated from a part of the attached cylinder. The numerical study shows the possibility of deflecting the incident sound by minimizing the acoustic surface impedance of the upper sections. The acoustical shadow region was more pronounced in both near- and far-field compared to the passive case with rigid surface, i.e. without active control. For a relatively wide frequency range it was possible to enhance shielding effects only with few secondary sources and error microphones. In this paper effects of some control parameters on the actively controlled sound field near the top edge of noise barriers are studied. Results of numerical study and model measurements are shown and discussed.

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A Mobile Robot Estimating the Real-time Moving Sound Sources by using the Curvature Trajectory (곡률궤적을 이용한 실시간 이동하는 음원을 추종하는 모바일 로봇)

  • Han, Jong-Ho;Park, Sook-Hee;Lee, Dong-Hyuk;Noh, Kyung-Wook;Lee, Jang-Myung
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.1
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    • pp.48-57
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    • 2014
  • It is suggested that the curvature trajectory be used to estimate the real-time moving sound sources and efficiently the robot estimating the sound sources. Since the target points of the real-time moving sound sources change, the mobile robot continuously estimates the changed target points. In such a case, the robot experiences a slip phenomenon due to the abnormal velocity and the changes of the navigating state. By selecting an appropriate curvature and navigating the robot gradually by using it, it is possible to enable the robot to reach the target points without having much trouble. In order to recognize the sound sources in real time, three microphones need to be organized in a straight form. Also, by applying the cross-correlation algorithm to the TDOA base, the signals can be analyzed. By using the analyzed data, the locations of the sound sources can be recognized. Based on such findings, the sound sources can be estimated. Even if the mobile robot is navigated by selecting the gradual curvature based on the changed target points, there could be errors caused by the inertia and the centrifugal force related to the velocity. As a result, it is possible to control the velocity of both wheels of the robot through the velocity PID controller in order to compensate for the slip phenomenon and minimize the estimated errors. In order to examine whether the suggested curvature trajectory is appropriate for estimating the sound sources, two mobile robots are arranged to carry out an actual experiment. The first robot is moved by discharging the sound sources, while the second robot recognizes and estimates the locations of the discharged sound sources in real time.

Direction and Location Estimating Algorithm for Sound Sources with Two Hydrophones in Underwater Environment (두 개의 하이드로폰을 이용한 수중 음원 방향 추정 및 위치 추정 알고리즘)

  • Shin, JaeWook;Song, Ju-Man;Lee, SeokYoung;Choi, Hyun-Taek;Park, PooGyeon
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.8
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    • pp.676-681
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    • 2013
  • For underwater vehicles, the use of sensors such as cameras and laser scanners is limited by the difference in environment compared to robots designed to work on dry land. In underwater environments, if use is made of sound signals, valuable information can be obtained. The most important application is the localization of underwater sound sources. The estimated location of a sound source can be used to control underwater robots or submarines. Thus, the purpose of this research is to estimate the source's direction and location in a noisy underwater environment. The direction of the sound source is obtained using two hydrophones. Furthermore, if we assume that the robot or sound source is moving, the location of the sound source is estimated using more than two estimated directions. The feasibility of the developed algorithm is examined by experiments in a water tank and in the ocean.