• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12C
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• pp.1035-1043
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• 2010

This paper presents a listening angle estimation scheme based on received signal power difference (RSPD) using acoustic signals, and analyzes the performance of the proposed scheme. The RSPD as the measurement to estimate the listening angle is considered for the first time in this paper. We mathematically analyze the error characteristics of the proposed scheme and present the characteristics of the proposed scheme through the Monte-Carlo simulation. We also conduct actual experiments in an anechoic room to evaluate the performance of the proposed scheme to compare with the conventional scheme.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.5
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• pp.9-17
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• 2010

This paper presents a localization perception of a phantom sound image for ultrahigh-definition TV with respect to various loudspeaker configurations; two-horizontal, two-vertical and triplet loudspeakers. Vector base amplitude panning algorithm with modification for non-equidistant loudspeaker setup is applied to create the phantom sound image. In order to practically study the localization performance in real situation, the listening tests were conducted at the on-axis and off-axis positions of TV in normal listening room. A method of adjustment which can reduce the ambiguity of a perceived angle is exploited to evaluate the angles of octave-band signals. The subjects changed the panning angle until the real sound source and virtually panned source were coincident. A spatial blurring can be measured by examining the differences of the panning angles perceived with respect to each band. The listening tests show that the triplet panning method has better performance than vertical panning in view of perceptual localization and spatial blurring at both on-axis and off-axis positions.

• Korean Journal of Applied Biomechanics
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• v.30 no.4
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• pp.301-309
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• 2020

Objective: This study aimed to investigate the effect of white noise on dynamic balance in patients with stroke during walking. Method: Nineteen patients with chronic stroke (age: 61.2±9.8 years, height: 164.4±7.4 cm, weight: 61.1±9.4 kg, paretic side (R/L): 11/8, duration: 11.6±4.9 years) were included as study participants. Auditory stimulus used white noise, and all participants listened for 40 minutes mixing six types of natural sounds with random sounds. The dynamic balancing ability was evaluated while all participants walked before and after listening to white noise. The variables were the center of pressure (CoP), the center of mass (CoM), CoP-CoM inclined angle. Results: There is a significant increase in the antero-posterior (A-P) CoP range, A-P inclination angle, and gait speed on the paretic and non-paretic sides following white noise intervention (p<.05). Conclusion: Our findings confirmed the positive effect of using white noise as auditory stimulus through a more objective and quantitative assessment using CoP-CoM inclination angle as an evaluation indicator for assessing dynamic balance in patients with chronic stroke. The A-P and M-L inclination angle can be employed as a useful indicator for evaluating other exercise programs and intervention methods for functional enhancement of patients with chronic stroke in terms of their effects on dynamic balance and effectiveness.

• The Journal of the Acoustical Society of Korea
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• v.25 no.1E
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• pp.8-13
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• 2006

In this paper, an Optimized Ambisonic Panning Algorithm (OAPA) which reduces sound localization error, is proposed. In the conventional Ambisonic Panning Algorithm (APA), sound localization is usually different from the panning angle, especially when listeners are not in an ideal listening position, because of low signal separation among other channels. To overcome this problem, an OAPA using window functions is proposed. A proper window function can be verified, comprising of higher harmonic components than 2M+1 and improved DPC and channel separation. Analysis results demonstrate that the proposed method results in higher signal separation among other channels and lower sound localization errors than the conventional APA.

• Journal of Biomedical Engineering Research
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• v.37 no.3
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• pp.112-118
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• 2016

The neck pain is fairly common occurance. Forward head posture and text neck are poor postures which may be related with neck pain but the evidence is not enough. We developed the wearable sensor which can assess the head & neck posture in daily life. Microprocessor, Bluetooth low energy, and 3-axis accelerometer, rechargeable battery and vibratior for reminding are used to implement the wearable sensor. Real-time algorithm to parameterize the posture for one epoch is implemented which classifies the posture in the epoch into three classed; dynamic, static_good posture, and static_poor posture. Also the algorithm makes reminding to its wearer to give them the prolonged poor posture is detected. The mean error of measurement was 1.2 degree. The correlation coefficient between neck angle and craniovertebral angle was 0.9 or higher in all cases. With the pilot study on text neck syndrome was also quatified. Average of neck angle were 74.3 degree during the listening in the classroom and 57.8 degree during the smartphoning. Using the wearable sensor suggested, the poor postures of forward head posture and neck neck can be detected in real-time which can remind the wearer according to his/her setting.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1B
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• pp.71-76
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• 2000

On multimedia teleconferencing system existing a number of participants, face of the participants can beperceived by visual image. However, differentiation of each participant's voice and spaciousness sense are very hard since voice of all participants is processed with one dimensional data. In this paper, we implemented three dimensional audio rendering system using the HRTF(Head Related Transfer Function) and distance sense reproduction method and determined the optimal location of the participants for teleconferencing system. In the results of the listening test using elevation and azimuth angle, we showed that directional perception of the azimuth angles were better than that of the elevation angles. Specially, we showed that participant location using the HRTFS of the azimuth angle 10" , 90" , 270" and350" was efficient in teleconferencing system existing four participants. We also proposed that distance cue was used for enhancement of the reality and location of many participants more than five.ipants more than five.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.4753-4761
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• 2013

This study recorded the sound of Korean traditional musical instruments by considering the radiation characteristics of traditional Korean musical instruments and setting the diverse mounting angle and distance of microphone. By following recorded results, the study analyzes the optimum position of microphone and the characteristic of timbre through frequency range spectrum and repeated listening. This experiment of study is for technique of close microphone which is used in popular music, therefore it is recorded in the popular music recording studio. The study also suggests the optimum position for the microphone to record, and explains the difference of timbre at different position. The result of study will suggest the best technique of Close Microphone Techniques for Korean Traditional Musical Instruments not only to accurately express the beautiful and unique sound of traditional Korean musical instruments but also to obtain diverse timbre.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.523-526
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• 2017

In modern recently technology, 3D-Audio is used to enhance immersion in Virtual Reality. This includes interest of people about VR and AR, which related to the field of computer graphics. In fact, a lot of research has been carried out in recent years into a 3D sound field. However, the existing 3D generator device used for virtual reality does not contain Doppler effect occurred by the sound comes to or leave from a listener, while an angle from the listener and the altitude of the source sound are applied. Therefore, this paper present 3D real sound utilizing Doppler effect with spatial-rotation-speaker. We map the source sound in 3D-space into a real space where a user stays and present 3D real sound by manipulating with rotation angle, phase difference, sound output volume of the sound in 3D-space, according to the location of a virtual source sound. Utilizing both natural Doppler effect of rotating sound that is occurring by spatial-rotation-speaker and artificial Doppler effect generated by frequency-modulation of sound quality could improving the virtual reality for sound condition for perspective listening.