• Journal of the KSME
• /
• v.35 no.10
• /
• pp.933-938
• /
• 1995

소음 공해의 문제는 수세기에 걸쳐 지속되어왔고, 현대 사회는 인간과 기계에 의한 소음으로 조용하고 평온한 삶을 영위하기가 점점 더 힘들어지고 있다. 소음은 일반적으로 원하지 않는 소리라고 정의된다. '원하지 않는'이란 말이 소음(noise)을 물리학적인 소리(sound)와 구멸하는 것이다. 아름다운 음악도 어떤이에겐 청각적 혼돈 상태로 느껴질 수 있듯이 어떠한 주어진 소 리를 '소음'이라 서술하는 것에는 심리 음향학(psychoacoustics)적인 요소가 강하므로 소음에 대한 연구는 그저 단순한 과학이 아니지만 그럼에도 불구하고 이는 음향학에 단단히 기초하고 있고 그전문어들을 이용한다. 따라서 음향학의 기초적인 이론과 심리음향학에 대하여 간단히 살펴보고 소음의 영항과 소음 환경을 이해한 뒤, 소음의 제어에 대한 예를 보는 것으로 소음 과학에 대한 개략적인 이해를 돕고자 하는 것이 이 글의 목적이다.

• Proceedings of the Korea Database Society Conference
• /
• 2000.11a
• /
• pp.358-363
• /
• 2000

본 논문에서는 디지털오디오 원시 데이터의 양에 따라 적당한 양의 오디오워터마크를 생성, 삽입하여 일정한 수준의 오디오데이터의 품질을 유지하도록 하는 적응적 워터마킹을 제안한다. 제안하는 알고리즘은 심리음향모델인 frequency masking과 Wavelet 변환의 개념을 적용한다. 저작권자 혹은 소유자의 데이터는 PN-sequence를 이용하여 생성된다. 워터마크 생성량의 조절은 특정한 모듈이 담당하게 되는데 이 모듈은 원시 데이터의 크기에 따라 워터마크의 적당한 양을 산출하여 오디오데이터의 품질을 유지하도록 한다.

• The Journal of the Acoustical Society of Korea
• /
• v.28 no.6
• /
• pp.557-565
• /
• 2009

To perceive the direction and the distance of a sound, we always use a couple of information. Head Related Transfer Function (HRTF) contains the information that sound arrives from a sound source to the ears of the listener, like differences of level, phase and frequency spectrum. For a reproduction system using 2 channels, we apply HRTF to many algorithms which make 3d sound. But it causes a problem to localize a sound source around a certain places which is called the cone-of-confusion. In this paper, we proposed the new algorithm to reduce the confusion of sound image localization. The difference of frequency spectrum and psychoacoustics theory are used to boost the spectral cue among each directions. To confirm the performance of the algorithm, informal listening tests are carried out. As a result, we can make the improved 3d sound in 2 channel system based on a headphone. Also sound quality of improved 3d sound is much better than conventional methods.

• The Journal of the Acoustical Society of Korea
• /
• v.27 no.4
• /
• pp.207-214
• /
• 2008

To create 3D sound, we usually use two methods which are two channels or multichannel sound systems. Because of cost and space problems, we prefer two channel sound system to multi-channel. Using a headphone or two speakers, the most typical method to create 3D sound effects is a technology of head related transfer function (HRTF) which contains the information that sound arrives from a sound source to the ears of the listener. But it causes a problem to localize a sound source around a certain places which is called cone-of-confusion. In this paper, we proposed the new algorithm to reduce the confusion of sound image localization. HRTF grouping and psychoacoustics theory are used to boost the spectral cue with spectrum difference among each directions. Informal listening tests show that the proposed method improves the front-back sound localization characteristics much better than conventional methods.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2009.10a
• /
• pp.827-827
• /
• 2009

Complaints against high-speed train interior noise have been increasing as a number of high-speed train passenger grows bigger. It is very difficult to analyze characteristics of high-speed train interior noise using sound pressure level only. It is requested to consider how the public response change for each high-speed train interior noise. This study presents evaluation of the sound quality for interior noise of KTX-II using Zwicker parameters. Characteristic of loudness and sharpness is different between noise samples depending on operation condition. The noise sample that recorded when the high-speed train passed through tunnel section is more louder and sharper.

• ETRI Journal
• /
• v.35 no.5
• /
• pp.859-868
• /
• 2013

The active noise control (ANC) technique attenuates acoustic noise in a flexible and effective way. Traditional ANC design aims to minimize the residual noise energy, which is indiscriminative in the frequency domain. However, human hearing perception exhibits selective sensitivity for different frequency ranges. In this paper, we aim to improve the noise attenuation performance in perceptual perspective by incorporating noise weighting into ANC design. We also introduce psychoacoustic analysis to evaluate the sound quality of the residual noise by using a predictive pleasantness model, which combines four psychoacoustic parameters: loudness, sharpness, roughness, and tonality. Simulations on synthetic random noise and realistic noise show that our method improves the sound quality and that ITU-R 468 noise weighting even performs better than A-weighting.

• Proceedings of the IEEK Conference
• /
• 2002.07a
• /
• pp.454-457
• /
• 2002

In this paper, we proposed digital audio watermarking algorithm for high quality audio. Nowadays, digital watermark used to confirm to digital copyright protection, not only digital image but also digital audio is active in the digital watermarking study. In this paper, we proposed digital audio watermarking algorithm using psychoacoustics model and MDCT/IMDCT (Modified Discrete Cosine Transform/Inverse Modified Discrete Cosine Transform) for the high quality audio watermark. In the proposed scheme, we used to 441KHz, 128kbps and stereo audio data for audio watermarking algorithm. Audio data is passed by MDCT; watermark can be inserted into the frequency domain with 256,1024 and 2048 interval.

• Proceedings of the IEEK Conference
• /
• 2000.09a
• /
• pp.189-192
• /
• 2000

본 논문에서는 청각 장애인의 보다 향상된 보청 환경을 조성하고자 청각손실을 심리음향 모델을 적용하여 감음 신경성 난청을 보정하는 알고리즘을 제안한다. 제안한 알고리즘에서는 난청의 유형은 내이에서부터 중추 뇌에 걸친 감음계와 신경계의 장애에서 비롯되는 감음신경성 난청(sensorineural hearing loss)으로 주파수 영역상에서 MTH(minimum hearing threshold)가 균일하지 않게 상승하게되어 가청영역이 좁아지는 문제점을 해결하기 위한 방법으로 각각의 주파수 밴드마다 멀티밴드 압축 알고리즘을 적용하였다. 그러나 이 경우 각각의 주파수 밴드에 따른 서로 다른 가청 영역의 영향에 의한 변형된 스펙트럼 모양으로 인해 spectral contrast reduction과 변형된 마스킹 특성으로 인해 음성 변별력에 제한을 가하게 된다. 이것은 주변 주파수 성분들에 의한 마스킹 효과에 의한 것으로, 신호에 대한 난청인이 느끼는 지각 영역(perceptual domain)에서의 해석과 심리음향 모델 파라미터를 통한 보청기의 개발이 이루어져야 하며, 본 논문에서 그 알고리즘을 적용하였다.

• Journal of KSNVE
• /
• v.10 no.2
• /
• pp.254-260
• /
• 2000

the reduction of the interior nosie level has been the main interest of NVH engineers in the development of vehicles. However, the consumer's perception on the car noise is affected largely by the psychoacoustic characteristics of the noise, as well as the sound pressure level. In this study, the quality of the vehicle interior nosie is analyzed by employing the subjective evaluations and by representing them in temrs of the objective quantities. The subjective evaluatins were performed for the seven vehicles in the range of subcompact to luxury cars. The methods of paired comparisons and semantic differential were used to study the preference, the quality of interior noise and their correlation. The linear regression models were obtained for the subjective evaluation and the sound quality metrics.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2014.04a
• /
• pp.165-170
• /
• 2014

Quantifying the perception of human is of great interest for the optimal characterization of the interaction of persons with their environment. The direct approach to such measurements is based on jury-test methods. In this study we considered which jury-test method is more efficient and exact way to measure the preferences for operating sound of car. Moreover we needed to research selection criteria of jury-test methods in accordance with the properties of sound samples. We choose two sample sounds; door locks which generate simple impact sounds and window lifts which are consisted of long and complex sound. For each sound sample we conducted two jury-test methods respectively and discussed about the results.