• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.388-393
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• 2012

Acoustic brightness and contrast control are promising techniques for manipulating acoustic energy over selected zones of interest using loudspeaker arrays. In this paper, the fundamental theory and concept of the brightness and contrast control is reviewed. The similarity and difference of two different strategies are explained in terms of the constraint required to determine a unique solution among many possible candidates. The application examples and recent progresses of the brightness and contrast control are presented.

• 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.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.111-114
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• 2004

웨어러블 컴퓨터와 같은 차세대 PC의 진화 방향은 인간이 느끼는 색상, 빛의 밝기, 소리, 향기, 맛, 감촉 등의 오감 정보의 효과적인 융합과 재현 및 사용자 중심의 인간-기계 관계의 형성으로 정의 된다. 그러나, 기능의 다양함과는 별개로, 휴대의 편이를 위한 착용형태의 H/W 플랫폼 개발은 효율적인 5 감 정보의 융합 및 재현에 제약을 가하고 있는 실정이다. 본 논문에서는, 현재 정부에서 국가적인 차원으로 현재 연구 개발중인 차세대 PC 플랫폼 기반에서의 효율적인 5 감 정보의 융합 및 재현이 가능한 S/W 플랫폼을 구현하며, 보다 효율적인 융합 및 재현을 위한 새로운 제어 메시지 형태를 제안한다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.12 s.105
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• pp.1378-1388
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• 2005

Spatial control of sound is essential to deliver better sound to the listener's position in space. As it can be experienced in many listening environments. the quality of sound can not be manifested over every Position in a hall. This motivates us to control sound in a region we select. The primary focus of the developed method has to do with the brightness and contrast of acoustic image in space. In particular, the acoustic brightness control seeks a way to increase loudness of sound over a chosen area, and the contrast control aims to enhance loudness difference between two neighboring regions. This enables us to make two different kinds of zone - the zone of quiet and the zone of loud sound - at the same time. The other perspective of this study is on the direction of sound. It is shown that we can control the direction of perceived sound source by focusing acoustic energy in wavenumber domain. To begin with, the proposed approaches are formulated for pure-tone case. Then the control methods are extended to a more general case, where the excitation signal has broadband spectrum. In order to control the broadband signal in time domain, an inverse filter design problem is defined and solved in frequency domain. Numerical and experimental results obtained in various conditions certainly validate that the acoustic brightness, acoustic contrast, direction of wave front can be manipulated for some finite region in space and time.