• Journal of Institute of Control, Robotics and Systems
• /
• v.2 no.3
• /
• pp.194-199
• /
• 1996

평면 배열형 소나 센서에서는 트랜스듀서 상호간의 간섭효과들이 음을 방사하는 각각의 트랜스듀서 및 평면 배열의 빔패턴에 영향을 주게된다. 따라서 음향 방사출력의 계산은 소나용 트랜스듀서의 성능및 효율을 평가하는데 필수적이다. 음향 방사출력을 예측하기 위하여 무한 강성 배플에 고정된 수개의 트랜스듀서를 이론해석의 대상으로 설정하였다. 각 트랜스듀서는 자기방사 임피던스 및 상호방사 임피던스로 구성되어 있으며 이것의 총 방사 임피던스 및 음향반사 출력의 추출은 등가 전기회로 모델을 이용하였다. 이론및 수치해석의 결과에 근거하여 음향방사 출력은 각 트랜스듀서 상호간의 간섭의 양에 의존함을 보였으며 상호간섭에 의한 음향출력 손실은 25.05%에서 최고 51.52%정도임을 확인하였다.

• Industry Promotion Research
• /
• v.5 no.2
• /
• pp.1-7
• /
• 2020

This study is a technology related to a lighting lamp that illuminates indoor or outdoor lighting with light. In more detail, a see-through window is created in all directions on a case constituting the exterior, and a jade stone processed in a thin panel form is attached to the see-through window. By constructing a lighting lamp, since the soft light is irradiated indoors or outdoors through the jade stone, it provides comfort and warmth to the user, enhances the indoor or outdoor interior effect, emits far-infrared rays and negative ions, and emits a subtle floral scent It is a technology for lighting lamps using jade stones that emit. The characteristics of the product of this research and development is that the viewing window is formed in all directions on the case constituting the exterior, and the lighting lamp is composed by attaching the processed jade stone in the form of a thin panel to the viewing window. It is meaningful that they studied lightings using jade stones that generate sounds such as Buddhist scriptures, the Bible, and Sijo.

• Proceedings of the Acoustical Society of Korea Conference
• /
• 1998.06c
• /
• pp.439-443
• /
• 1998

본 연구에서는 50% Tukey 창함수를 이용하여 위너필터를 설계하고 표면결함의 영상을 개선하였다. 이 위너필터는 높은 공간주파수 성분에 대해 낮은 잡음이득을 주며 안정된 필터 동작 특성을 보였다. 실험을 위하여 쿼드러춰 방식의 초음파현미경을 구성하고 시편으로 10원주화를 사용하였다. 실험결과 개선된 영상은 블러링 효과가 제거되어 우수한 영상 화질을 나타내었다.

• The Journal of the Acoustical Society of Korea
• /
• v.23 no.2
• /
• pp.146-161
• /
• 2004

There have been always some difficulties in target setting and conditioning of acoustic performances of the Korean traditional music hall due mainly to the lack of the information on the sound radiation characteristics of Korean musical sources. In this study, the radiation characteristics of four typical Korean traditional musical sources were investigated in precision and their usage was demonstrated: The selected musical sources were Gayageum (string), Daegeum (woodwind), Jango (drum), and Pansori Chang (vocal performance). Each sound source was located at the center of a semi-anechoic chamber and the directivity was determined by the measured sound pressure levels in every 10° angular position, for both vertical and horizontal directions. The directivity pattern of Gayageum varies from a uniform to a complex pattern having many side lobes with the increase of frequency. The main radiation of Daegeum is toward the upward direction. The directivity pattern of Jango is clearly a side-oriented one and the left direction intensity is sharper than its right side at low frequencies. For the Chang, the directivity pattern change from a uniform pattern to a frontally directed one as the frequency goes high. Measured directional and spectral characteristics of traditional Korean music sources were implemented into the computation of architectural acoustic measures for the Busan National Korean Traditional Music Hall which is under construction. Parameters such as RT, SPL, C80, IE, STI were calculated at two receiver positions by using a ray tracing technique. Significant differences in the acoustic measures at receiver positions were observed between the results in using the omni-directional source and the directional one. It is thought that the suggested source data and design method can be used as a basic reference in the future acoustic design of performance halls for the Korean traditional music.

• The Journal of the Acoustical Society of Korea
• /
• v.15 no.1
• /
• pp.17-22
• /
• 1996

Planar array of acoustic transducer is normally used in a sonar system. Acoustic radiation makes beam pattern in underwater uses. The main source of the beam pattern is due to the transducer array. Therefore, estimation of the acoustic radiated power is necessary to predict the performance and efficiency of the transducer. As an example of the acoustic radiation power, nine acoustic transducers mounted to a rigid infinite baffle are considered in a theoretical model. Each piston's acoustic radiation consists of self- and mutual-radiation impedances. Total radiation impedances and acoustic radiation power of the transducers are extracted using on the theory of an equivalent electric circuit. The theoretical results reveal that acoustic radiation power of the transducer depends on the mutual coupling effects.

• Proceedings of the Acoustical Society of Korea Conference
• /
• autumn
• /
• pp.551-554
• /
• 2004

현재 국악기의 음향특성에 대한 상세 정보가 매우 부족하며, 이러한 점보의 부재는 국악당의 설계에 있어서 최적의 음향을 전달하는 공간을 형성하지 못하게 하는 한 원인이 되고 있다. 따라서, 대표적인 각종 국악기의 음향특성을 측정하고 분류한 후 데이터베이스를 구축하면, (1) 향후의 국악 및 국악기 개발에 대한 기초연구로서 활용들 수 있으며, (2) 국악전용 연주장의 설계에 있어서 입력 데이터로 요긴하게 활용될 수 있으리라 판단된다. 본 연구는 국악기의 음향방사특성을 조사하기 위한 제 2 단계의 연구로서, 기존의 연구 [1] 에 새로운 국악기 8 종을 추가하였다. 선정된 국악기는 현악기중에서 거문고와 해금, 관악기 중에서 피리와 태평소, 타악기 중 북과 꽹가리, 징 및 남성창으로, 원거리 (far-field) 음향 방사 특성을 조사하였다.

• Proceedings of the Acoustical Society of Korea Conference
• /
• autumn
• /
• pp.441-444
• /
• 1999

• Proceedings of the Acoustical Society of Korea Conference
• /
• 1998.06c
• /
• pp.167-170
• /
• 1998

음성신호의 특징적인 성분인 피치를 검출하는 알고리즘 중 실시산 구현이 손쉬운 3단계를 클리핑 알고리즘을 PC상에서의 처리를 위하여 구현하였다. 이 알고리즘을 통하여 검출되는 피치의 안정성 및 정확성을 높이기 위해서 적용된 창함수, LPF, 클리핑 자기상관값계산, 비선형 감쇄, 등의 전처리 필터링과, 배수피치 검출 및 정정, 메디언 필터링을 사용하여 피치를 검출하였다. 또한 이 알고리즘을 이용하여 DSP의 도움을 얻지 않고 PC상에서 음성을 분석하여 스펙트로그램, 파형, 에너지, 피치 등을 출력하는 프로그램인 Visual Analysis Tool for sounds(VAT)의 출력화면을 통하여 피치검출을 나타내었다.

• Proceedings of the Acoustical Society of Korea Conference
• /
• autumn
• /
• pp.149-152
• /
• 2000

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2011.04a
• /
• pp.285-290
• /
• 2011

For developing acoustic window, transmission loss in accordance with incident angle was calculated and compared with measurement results. In design stage, the material choice of acoustic window is very important because the material is parameter of transmission loss and structural strength. In order to analyze the effect of material properties on transmission loss, the parametric studies were carried out and the results were discussed in this paper.