• Journal of the Ergonomics Society of Korea
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• v.25 no.4
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• pp.9-22
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• 2006

1/f fluctuation characteristics can be seen in various natural phenomena, such as breezes, streams, candle flames and the luminous patterns of fireflies. It is said that the 1/f fluctuation are comfortable for human beings. And they are introduced into many industrial products, such as an air conditioner, music, lighting, etc. This study focused on verifying the effects of 1/f fluctuation sound on comfort sensibility. Stimulus were divided into three groups(Group 1, 2, 3) by sound generation methodology. Fluctuation patterns of group 1, 2 were given by three types of fluctuation, 1/f0, 1/f1, 1/f2, and its of group 3 were given by two types of pure tone, 1/f1. In order to verify the effects, we measured the physiological responses of the subjects such as EEG(Electroencephalogram), ERP(Event-Related Potential), and these physiological responses were compared with subjective assessments, free answers. Consequently, we found that factor which had an effect on comfort sensibility was cognitive factor(for stimulus) rather than 1/f fluctuation sound pattern.

• Journal of the Ergonomics Society of Korea
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• v.24 no.2
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• pp.79-83
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• 2005

In order to verify the effects of sleep efficiency and sleep latency depending on the sound, Polysomnography was carried for the different sound stimulations, such as Sound A(providing R bed Co.), Sound B(1/f fluctuation sound develope by KRISS), and no sound stimulation. In case of sleep efficiency and WASO(wake after sleep onset) ratio Sound B shows more affirmative effect than no sound stimulation or Sound B. It is the result that the effect is caused because 1/f fluctuation sound has the rule and unexpectation. This research results show the possibility of application and development of the sound for sleep.

• Science of Emotion and Sensibility
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• v.18 no.3
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• pp.63-70
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• 2015

This study identified heart response of participants while listening to sounds which have 1/f fluctuations with exponent ${\alpha}$ gradient. The participants were engaged in emotional stress work. Prior studies related to 1/f fluctuation sound have reported that sound source can alleviate psychological and physiological state of users. Subjects of this study were exposed to sound with three levels of ${\alpha}$ gradient. Heart response of subjects were measured with Photoplethysmography(PPG) sensor simultaneously. The dependent variables of this study were beat per minute(BPM), very low frequency percent of pulse rate variability (VLF percent), the standard deviation of all normal RR intervals (SDNN), and high frequency power(HF power). Subject showed arousal response when exposed to sound with exponent ${\alpha}$ gradient of 3 whereas the sound with exponent ${\alpha}$ gradient of 1 and 2 resulted in relax effect. The characteristic of 1/f fluctuation sounds can be applied to alleviate stress for employers under emotional labor.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1827-1832
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• 2003

In this research, the simulation method for acoustic sounds by a uniform flow around a two-dimensional circular cylinder by using the finite difference lattice Boltzmann model is explained. To begin with, we examine the boundary condition which determined with the distribution function $f_i^{(0)}$ concerning with density, velocity and internal energy at boundary node. Very small acoustic pressure fluctuation, with same frequency as that of Karman vortex street, is compared with the pressure fluctuation around a circular cylinder. The acoustic sound' propagation velocity shows that acoustic approa ching the upstream, due to the Doppler effect in the uniform flow, slowly propagated. For the do wnstream, on the other hand, it quickly propagates. It is also apparently the size of sound pressure was proportional to the central distance $r^{-1/2}$ of the circular cylinder. The lattice BGK model for compressible fluids is shown to be one of powerful tool for simulation of gas flows.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2000.04a
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• pp.144-148
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• 2000

A new paradigm is urgently needed to create the textile product that appeal to human Kansei or Gosei. A future of textiles depends heavily on this new paradigm. In order to create new paradigm Kansei color designs by pleasant sound are tried. These computing color designs are treated by the method of Fast fourier Transformation. As several result good color designs are given in forms of ring color patterns and band. But these judgments depend finally on human kansei. These new technology give us good hints in order to create new paradigm that appeal to Kansei goods. This new concept should be developed to higher level by additional improvements.

• Science of Emotion and Sensibility
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• v.9 no.1
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• pp.39-48
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• 2006

This study was carried out to investigate sound sensation of Korean traditional silk fabrics with similar sound pressure levels (SPL) and to identify secondary physical factors excluding SPL which determine sound sensation of the fabrics. Sounds of the silk fabrics tended to be perceived differently from one another as for some of sensation such as clearness ant roughness. They were felt more strongly in aspects of loudness, roughness, and highness than of softness, sharpness, clearness, and pleasantness. Subjective clearness, roughness, and highness were significantly correlated with some of sound parameters including roughness(z), ${\Delta}L,\;and\;{\Delta}f$. Especially, both of clearness and roughness which were varied among the fabrics were found as determined by ${\Delta}L$. This result means that ${\Delta}L$ as well as roughness(z) and ${\Delta}f$ could be utilized secondary to SPL in order to satisfy some of human sensibility for sound from traditional silk fabrics without variation of physical loudness.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.547-554
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• 2014

In this study, have researched 'a' index from three sound sources, effects on subject and finding optimal 'a' index, which can improve subject's stability, concentration and productivity. Check the health status of subjects who were selected 5 male and 5 female university students, and the period of this experiment was about two months. It were measured each subject's EEG, HRV and vibra image to analyze transition of stability, concentration, stress and heart beat. The results was measured in an environmental test room of temperature $25[^{\circ}C]$, the relative humidity 50 [%], illuminance 1,000 [lux] and air current speed 0.02[m/sec] with 'a' index of three sound sources which are a=1.106, a=1.749 and a=2.227. Results in a=1.106 compared to before exposure, relative $S{\alpha}$ wave, relative $L{\beta}$ wave and relative $M{\beta}$ wave have been revitalized, asymmetry index, stress and HRV have been decreased. Thus, to increase stability, concentration and productivity, also to decrease stress, changes in sound source of a=1.106 was found to be the most effective.

• IE interfaces
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• v.18 no.2
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• pp.158-166
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• 2005

Human-error and mental stress caused by psychophysiological dissonance between people and artificial environments have become a social problem. And it is a common knowledge that comfort environment reduces human-error and mental stress. Comfort sensibility is related to complex interactions between fabric, climatic, physiological and psychological variables. Currently, comfort sensibility has been evaluated by many sensory tests. However, it is difficult to evaluate comfort sensibility because a concrete concept of comfort sensibility is hard to define. In this paper, we propose a model to evaluate the comfort sensibility using Fuzzy-weighted score on an individual's subjective state for the stimulus. To represent the degree of comfort sensibility level for the stimulus, we represent comfort sensibility using 2 dimensional sensibility vector model. And we use the fuzzy-weighted score that is a fuzzy version of the weighted checklist technique computerized for evaluating the subjects. As an example, this model is applied to 1/f fluctuation sound evaluation. The results show that this model can be effectively used to the quantitative evaluation of comfort sensibility for the stimulus.