• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.263-268
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• 1999

Psychoacoustic characteristics of automobile hems influence subject's subjective evaluation and psychophysiological reactions on the sounds of car horns. However, differentiation of physiological responses to commercially availablenfluence subject's subjective evaluation and psychophysiological reactions on the s horns is a complicated task due to the small contrast in technical features of horns and the influence of habituation. Using 10 college students, comparative analysis of physiological reactivity was carried out in order to identify the effect of habituation on decrement of psychophysiological responsivity, assess the ability to differentiate subjectively most and least preferred/appropriate horns according to physiological manifestations. EEG and autonomic responses to 7 automobile horns were analyzed during 3 blocks of trials (each block was varied in order for presenting stimuli and acoustic parameters of horns). It was shown that electrodermal and cardiovascular responses had different reactivity patterns to repeated stimulation. Skin conductance variables (SCL, SCR) were habituated as a function of trial. Cardiac reactivity (HR, RSA) showed no signs of habituation. In contrast, sensitization was shown in the vascular component of response (pulse volume). The temporal EEG exhibited marked habituation of fast beta band power, while alpha-blocking effect did not habituate during the course of experiment. Differentiation of physiological responses of most and least preferred/appropriate horns was possible in this study. That is, some cardiovascular reactivity variables (HR, RSA, pulse volume, etc.) were differentiated between the least and the most preferred/appropriate horns during the experiment. However, EEG and electrodermal parameters showed significant differences only during first block of trials and were later affected by habituation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.10
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• pp.923-929
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• 2017

Generally, the sound emitted from a vehicle powered by an electric motor is lower than that of internal combustion engine vehicles. Therefore, pedestrians often cannot detect approaching electric vehicles. Therefore, a certain additional warning sound is required for these types of automobiles. In this study, to develop an audible warning sound, nine warning sounds are designed based on signal processing and chord theory. The background noise measured on the road is also added to these synthetic sounds. The detectability of these warning sounds is evaluated by subjective tests. The sound metric is correlated to detectability and is investigated through psychoacoustic theory and subjective evaluation. It is determined that known psychoacoustic parameters such as loudness, sharpness, and roughness have a low correlation with detectability. However, it is found that the interval of harmonic sound correlates well with detectability.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.3
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• pp.381-386
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• 2008

Virtual 3D audio methods that create 3D sound effects are researched highly for multimedia devices using 2 speakers or headphone. The most typical method to create 3D effects is a technology through use 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 can decline some 3D effects by cone of confusion between front and back directions due to the non-individual HRTF depending on each listener. In this paper, we propose a new method to use psychoacoustic theory that creates realistic 3D audio. In order to improve 3D sound, we calculate the excitation energy of each symmetric HRTF and extract the ratio of energy of each bark range. Informal listening tests show that the proposed method improves the front-bach sound localization characteristics much better than the conventional methods.

• ETRI Journal
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• v.27 no.5
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• pp.608-616
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• 2005

Watermarking has become a technology of choice for a broad range of multimedia copyright protection applications. This paper proposes an audio watermarking scheme that uses the modified tonal masker as an embedding carrier for imperceptible and robust audio watermarking. The method of embedding is to select one of the tonal maskers using a secret key, and to then modify the frequency signals that consist of the tonal masker without changing the sound pressure level. The modified tonal masker can be found using the same secret key without the original sound, and the embedded information can be extracted. The results show that the frequency signals are stable enough to keep embedded watermarks against various common signal processing types, while at the same time the proposed scheme has a robust performance.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.1243-1246
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• 1998

Three-dimensional(3-D) sound is a technique for generating or recreating sounds so they are perceived as emanating from locations in a three-dimensional space. Three dimensional sound has the potential of increasing the feeling of realism in music or movie soundtracks. Three-dimensional sound effects depend on psychoacoustic spectral and phase cues being presented in a reproduced signal. In this paper we propose an effective algorithm for the sound image expansion in television system using stereo image enhancement techniques. Compared to the other techniques of three-dimensional sound, the proposed algorithm use only two speakers to enhance the sound image expansion, while maintaining the original sound characteristics.

• Fibers and Polymers
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• v.6 no.3
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• pp.269-276
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• 2005

In this study, cross-cultural comparison of sound sensation for Korean traditional silk fabrics between Korea and America was performed and prediction models for sound sensation by objective measurements including sound parameters such as level pressure of total sound (LPT), Zwicker's psychoacoustic characteristics, and mechanical properties by Kawabata Evaluation System were established for each nation to explore the objective parameters explaining sound sensation of the Korean traditional silk. As results, Koreans felt the silk fabric sounds soft and smooth while Americans were revealed as perceiving them hard and rough. Both Koreans and Americans were pleasant with sounds of Gongdan and Newttong and especially Newttong was preferred more by Americans in terms of sound sensation. In prediction models, some of subjective sensation were found as being related mainly with mechanical properties of traditional silk fabrics such as surface and compressional characteristics.

• Phonetics and Speech Sciences
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• v.1 no.4
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• pp.17-27
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• 2009

Despite many studies on the production and perception of L2 phonemes, studies on how such phonemes are encoded lexically remain scarce. The aim of this study is to examine whether L2 learners have a perceptual problem with L2 suprasegmentals which are not present in their L1, or if they are able to perceive but not able to encode them in their lexicon. Specifically, Korean learners were tested to see if they could discriminate the vowel length differences in Japanese at the psychoacoustic level through a simple AX discrimination task. Then, a speeded lexical decision task with high phonetic variability was conducted to see whether they could use such contrasts lexically. The results showed that Korean learners of Japanese have no difficulties in discriminating Japanese vowel length contrast, but they are unable to encode such contrast in their phonological representation, even with long L2 exposure.

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

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.8 s.101
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• pp.939-944
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• 2005

In this paper, a sound quality index for the evaluation of the vehicle intake noise was developed through a correlation analysis of the objective measurement and the subjective evaluation. First, intake orifice noise was measured at the wide-open throttle sweep condition. And then, the acoustic transfer function between intake orifice noise and interior noise was measured. Simultaneously, subjective evaluation was carried out with a 10-scale score by 8 special engineers. The correlation analysis between the psychoacoustic parameters derived from the measurement and the subjective evaluation was performed. The most critical factor was determined and the corresponding sound quality index for intake noise was obtained from the multiple factor regression analysis method. Finally, the effectiveness of the proposed index was validated.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.275-278
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• 2004

In TV sound system, loudspeakers are subject to severe size constraints. The small size of the transducer affects the low frequency signal performance of the system. Bass signal performance contributes significantly to the user perceived sound quality and a good bass signal reproduction is essential. Increasing the sound energy in the bass signal range is an unviable solution since the gain required are exceedingly high and signal distortion occurs because of the speaker overload. Recently methods are being proposed to invoke low frequency illusion using psychoacoustic phenomena of the missing fundamental. This paper proposes a simple and effective signal processing method to create bass signal illusion in TV speakers using the missing fundamental effect, at a complexity of 12 MIPS on Motorola 56371 audio DSP.