• 제어로봇시스템학회논문지
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• 제18권2호
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• pp.126-132
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• 2012

The technique for estimation of sound source direction is one of the important methods necessary for various engineering fields such as monitoring system, military services and so on. As a new approach for estimation of sound source direction, this paper propose the bio-mimetic localization sensor based on mechanically coupling structure motivated by hearing structure of fly, Ormia Ochracea. This creature is known for its outstanding recognition ability to the sound which has large wavelength compared to its own size. ITTF (Inter-Tympanal Transfer Function) which is the transfer function between displacements of the tympanal membranes on each side has the all inter-tympanal information dependent on sound direction. The peak and notch features of desired ITTF can be generated by using the appropriate mechanical properties. A example of estimation of sound source direction using generated ITTF with monotonically changing notch and peak patterns is shown.

• Journal of the Korean Wood Science and Technology
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• 제43권2호
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• pp.206-213
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• 2015

This study was carried out to use carbonized medium density fiberboard (MDF) for the replacement of sound absorbing material. Carbonization treatment was performed to improve sound absorption property for MDF at carbonizing temperatures of $500^{\circ}C$, $700^{\circ}C$, $900^{\circ}C$ and $1100^{\circ}C$. As the carbonization temperature increased, the results of the observation by scanning electron microscope (SEM) demonstrated that the fibers exhibited a more compressed morphology within the surface section of the MDF than those within the middle section of MDF. As the carbonizing temperature increased, the cavity increased. The sound absorption coefficient increased between the temperatures of $500^{\circ}C$ and $900^{\circ}C$, but decreased at a temperature of $1100^{\circ}C$. The sound absorption properties of the carbonized MDF and the non-carbonized MDF were compared. The maximum sound absorption coefficient of the carbonized MDF was 12.38%. This was almost double of the value of the non-carbonized MDF.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권12호
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• pp.5936-5954
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• 2018

Eight out of the top ten the largest technology companies in the world are involved in some way with the coming mobile VR revolution since Facebook acquired Oculus. This trend has allowed the technology related with mobile VR to achieve remarkable growth in both academic and industry. Therefore, the importance of reproducing the acoustic expression for users to experience more realistic is increasing because auditory cues can enhance the perception of the complicated surrounding environment without the visual system in VR. This paper presents a audio downmixing system for auralization based on hardware, a stage of sound rendering pipelines that can reproduce realiy-like sound but requires high computation costs. The proposed system is verified through an FPGA platform with the special focus on hardware architectural designs for low power and real-time. The results show that the proposed system on an FPGA can downmix maximum 5 sources in real-time rate (52 FPS), with 382 mW low power consumptions. Furthermore, the generated 3D sound with the proposed system was verified with satisfactory results of sound quality via the user evaluation.

• 산업기술연구
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• 제17권
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• pp.51-72
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• 1997

음속에 대한 실험값은 보통의 PVT 측정값보다 훨씬 정확하게 얻을 수 있고 또한 정적, 동적 성질을 동시에 얻을 수 있으므로 유체의 구조를 이해하는 방법으로 간주되어 오고 있다. 본 연구에서는 음속의 열역학적 성질에 대한 여러 이론을 기술하고 측정된 음속의 실험값들로부터 열역학적 성질을 추출해내는 여러 방법들에 대해 검토한다.

• 수산해양기술연구
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• 제35권4호
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• pp.391-396
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• 1999

It is well known that fish hear a wide frequency range of sound using both laterial line and inner ear, and the sound is probably the most effective channel for long-range communication underwater than any other stimulus.The auditory threshold of svenband grouper, Epinephelus septem fasciatus was determined by conditioning method using a sound coupled with electric shock in a tank. The audio-signals and electric shock used in the experiment were pure tones of 100 to 1000Hz and DC 6n.The response of fish to the sound was observed by ECG intervals from precordial leads method (V1·V2 method). The auditory threshold curve for sevenband grouper was V-shaped, with most sensitive threshold at 350Hz in the range of 100~1000Hz. The Sevenband grouper were more sensitive to sounds of 200~400Hz than to adjacent frequencies.

• 한국군사과학기술학회지
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• 제7권4호
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• pp.36-43
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• 2004

In 1909 Hiram P. Maxim invented one of the first metal silencers for reducing sound levels in firearms. Silenced me have been mainly applied in the hunting and military operation. In particular special force make use of silenced rifle because it is low sound level. This paper considers experimental analysis for the characteristics of shock wave caused by shooting of a silenced me. Experimental results Indicate that the sound level of K-7 silenced rifle was lower than the sound level of MP5 silenced rifle. And, Sound Power Level of K-7 silenced rifle at a distance more than 75m or loom have nearly the constant value. This results that suggested the characteristics data about K-7 rifle's impulse noise will be apply to design the silencer of a small arms.

• Journal of the Korean Wood Science and Technology
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• 제33권5호통권133호
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• pp.45-49
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• 2005

The sound absorption coefficients of three types commercial fiberboard were experimentally measured under a relatively low frequency range of 50 to 1600 Hz by the two microphone transfer function method. The sound absorption coefficient of 30 mm thick fiberboard was higher than that of 18 mm thick fiberboard at the frequency range of 50 to 1.2 KHz. The sound absorption coefficient of medium density fiberboard was a little higher than that of low density fiberboard.

• Educational Technology International
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• 제14권1호
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• pp.41-53
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• 2013

On the basis of two premises and embodied cognition theory, the vibration tactile learning is proposed as an effective method for foreign language learning. The premises are: the real nature of language is sound and the source of sound is vibration. According to embodied cognition theory, cognition is inherently connected to bodily sensation rather than metaphysical and independent. As a result, the vibration tactile learning is: people are able to learn foreign language better by listening to sound and experiencing its vibration through touch rather than solely listening to sound. The effectiveness of vibration tactile learning is tested with two instructional media theories: media comparison and media attribute. For the comparison, an experiment is conducted with control and experimental groups. The attributes of vibration tactile media are investigated in points of relationships with the learning process. The experiment results indicate a small effect on the increased mean score. Three kinds of relationships are found between the media attribute and learning process: enforced stimulus, facilitated pronunciation, and assimilation of resonance to sound patterns through touch. Finally, this paper proposes a new theoretical development for instructional media research: an embodied cognition based media research and development.

• 대한인간공학회지
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• 제29권2호
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• pp.217-224
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• 2010

Research has been conducted to examine the effects of mechanical and sound characteristics of fabrics on affective quality. The present study developed the Affective Quality Evaluation and Estimation System for Textiles (AQEEST) with distinguished features that can be effectively used in the affective research of fabric frictional sound. The AQEEST consists of three subsystems (affective quality evaluation, affective quality estimation, and audible distance estimation subsystems) and each subsystem consists of three to four modules (e.g., evaluation condition setup, evaluation experimentation, and textile database management modules) depending on its functional requirements. The affective quality evaluation subsystem was designed to help administer an experiment in a systematic manner and present acoustic and visual stimuli simultaneously in various gait conditions (walking, jogging, and running) to mimic a more realistic situation of textile frictional sound production. Next, the affective quality estimation subsystem was designed to estimate the sound characteristics, affective qualities, overall psychological satisfaction, and reference cluster of a textile using its mechanical and/or sound characteristic information. Lastly, the audible distance estimation subsystem was designed to estimate the just noticeable sound pressure levels and audible distances of a textile for various gait conditions using its mechanical characteristic information. The AQEEST can be upgraded by accommodating more affective quality study results for various textiles.

• International Journal of Advanced Culture Technology
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• 제10권4호
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• pp.286-293
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• 2022

In this study, we extracted sound waves that can improve psychological skills for volleyball players, investigated the changes that the application training of the extracted sound waves has on the brain waves of volleyball players, and the changes in brain waves are the psychological of volleyball players. The purpose of the research is to investigate the effect on technology. In order to achieve this purpose of the study, a total of 10 people from the experimental group and 10 from the control group were selected as the research subjects of university volleyball players with more than 5 years of volleyball experience. The experimental procedure was for the experimental group to listen to sound waves for more than 30 minutes at least 4 times a week for 12 weeks, and brain waves were measured 3 times before, during, and after. In addition, psychological skills were measured twice before and after. The measured data were subjected to t-test and two-way variance repeated measures analysis using SPSS 20.0. The results obtained through this process are as follows. First, as a result of analyzing the differences in psychological skills according to sound wave application training, there were statistically significant differences in goal setting and attention factors of the experimental group. Second, as a result of repeated measurement variance analysis at each time point according to the application of the sound wave application training program, it was found that alpha waves had a synergistic effect at the statistical significance level in the experimental group. Third, as a result of repeated measurement variance analysis at each time point according to the application of the sound wave application training program, it was found that the beta wave had a synergistic effect at the statistical significance level in the experimental group.