• The Transactions of the Korean Institute of Electrical Engineers P
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• 제62권2호
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• pp.103-109
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• 2013

In this study, the three sounds effects on subjects due to EEG type, and it researched to find optimal sound to increase their amenity and productivity. EEG and HRV were compared and analyzed in the environmental test room by classifying subjects into two type: A and B. The condition of the environmental test room was in temperature $31[^{\circ}C]$, relative humidity 50[RH%], air current speed 0.02[m/s] and illuminance 1000[lux] with setting up three different sounds which are U type sound, V type sound and Z type sound. The result of this study, at U type sound for A and B type, relative $M{\alpha}$ wave, relative $M{\beta}$ wave and SEF50 were revitalized. Also at Z type sound for A and B type, stress index, fatigue degree and HRT were decreased and SDNN was revitalized. Therefore U type sound is very effective to increase amenity, productivity and concentration, and Z type sound is very effective to decrease stress and fatigue degree.

• Transactions of the Korean Society of Mechanical Engineers B
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• 제25권9호
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• pp.1165-1174
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• 2001

The objective of this study is to understand the generation mechanism of sound and to develop a prediction method for the acoustic pressure field of a centrifugal fan. If the fan is operating at the free field without the casing, the acoustic analogy is a good method to predict the acoustic of the fan. But, the casing gives a dominant effect to the radiated sound field and the scattering effect of casing should be considered. So, in this paper the Kirchhoff-BEM is developed, which can consider the scattering effect of the rigid body. In order to consider the scattering and diffraction effects owing to the casing, BEM is introduced. The source of BEM is newly developed, so the sound field of the centrifugal fan can be obtained. In order to compare the predicted one with experimental data, a centrifugal impeller and a wedge are used in the numerical calculation and the results are compared with the experimental data. Reasonable results are obtained not only for the peak frequencies but also for the amplitudes of the tonal sound. The radiated acoustic field shows the diffraction and scattering effects of the wedge clearly.

• Journal of The Korean Society of Integrative Medicine
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• 제8권4호
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• pp.291-305
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• 2020

Purpose : The duration of speech segments reflects children's speech motor development. The purpose of this study was to determine whether segmental sound and word duration varies by age among preschool children. Methods : A total of 60 children aged 4~5 years participated in this study. Participants took the picture-naming test to produce single-word speech data. The duration of the consonant at the initial position of the word and the final position of the word, the voice onset time of plosive, the duration of the vowel following the initial consonant, and the duration of the word were measured. Results : As age increased, the duration of the initial consonant, the duration of the word, and the voice onset time decreased significantly. The main effects of age, manner of articulation, and place of articulation on the duration of the initial consonant were significant. The duration of consonants in the nasal sound and plosives and the duration of bilabial and alveolar sound differed significantly between groups. The main effects of age and vocal type on voice onset time were significant. The main effect of age on the duration of the consonant in the final position of word and on the duration of the vowel were not statistically significant. Conclusion : The results of this study showed that the duration of segmental sound and the word were associated with speech development between 4 and 5 years old. Accordingly, duration of the segmental sound and the word may serve as an acoustic cue as they reflect speech development and speech motor control maturity.

• Korean Journal of Adult Nursing
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• 제19권5호
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• pp.127-137
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• 2007

Purpose: It was investigated if abdominal meridian massage has effects on constipation in institutionalized psychiatric patients taking antipsychotic drugs. Methods: According to the constipation screening tests, 22 patients were selected as subjects. One group pre and post repeated measurement design was used. Constipation was operationalized as perceived constipation, frequency of defecation, frequency of bowel sound, and number of medicine taken to relieve constipation. Abdominal meridian massage was given for two weeks, 10-15 minutes each time and 10 times in total. Results: Perceived constipation, frequency of bowel sound, and number of medicine taken were significantly improved after massage. Except for number of medicine taken, the effects on perceived constipation and frequency of bowel sound were found to be persistent 2 weeks after massage. Conclusion: Based upon these results, abdominal meridian massage was recommended as independent nursing intervention for the relief of constipation in psychiatric patients who taking anti-psychotic drugs. Further studies to investigate the maximal duration time of effects and whether the effects of intermittent application of this method is more beneficial than the continuous application of this method are necessary.

• Journal of Advanced Marine Engineering and Technology
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• 제41권1호
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• pp.50-55
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• 2017

Foamed aluminum is an eco-friendly material that is reusable and safe against fire. These superior characteristics have many advantages in the field of building and construction and in cruise ships as sound absorbers. So far, the research on foamed aluminum has been focused on the sound absorption performance using the foaming ratio. Foamed aluminum, when compared with the existing sound absorbers such as glass wool or rock wool, has a better structural performance, and it can be installed on walls in many different ways. This study conducted experiments on the sound absorption characteristics considering the various applications of foamed aluminum. The effects of painting surfaces with the finishing material were compared to that of the normal surface, and the effects of vertical installation and hanging from the ceiling was compared with the effects of installing on the floor.

• Journal of Audiology & Otology
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• 제24권4호
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• pp.174-179
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• 2020

Background and Objectives: The integration of auditory-visual speech information improves speech perception; however, if the auditory system input is disrupted due to hearing loss, auditory and visual inputs cannot be fully integrated. Additionally, temporal coincidence of auditory and visual input is a significantly important factor in integrating the input of these two senses. Time delayed acoustic pathway caused by the signal passing through digital signal processing. Therefore, this study aimed to investigate the effects of hearing loss and hearing aid digital delay circuit on sound-induced flash illusion. Subjects and Methods: A total of 13 adults with normal hearing, 13 with mild to moderate hearing loss, and 13 with moderate to severe hearing loss were enrolled in this study. Subsequently, the sound-induced flash illusion test was conducted, and the results were analyzed. Results: The results showed that hearing aid digital delay and hearing loss had no detrimental effect on sound-induced flash illusion. Conclusions: Transmission velocity and neural transduction rate of the auditory inputs decreased in patients with hearing loss. Hence, the integrating auditory and visual sensory cannot be combined completely. Although the transmission rate of the auditory sense input was approximately normal when the hearing aid was prescribed. Thus, it can be concluded that the processing delay in the hearing aid circuit is insufficient to disrupt the integration of auditory and visual information.

• Investigative Magnetic Resonance Imaging
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• 제2권1호
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• pp.50-57
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• 1998

MR acoustic sound or noise due to gradient pulsings has been one of the problems in MRI, both in patient scanning as well as in many areas of psychiatric and neuroscience research, such as brain fMRI. Especially in brain fMRI, sound noise is one of the serious noise sources which obscures the small signals obtainable from the subtle changes occurring in oxygenation status in the cortex and blood capillaries. Therfore, we have studied the effects of acoustic or sound noise arising in fMR imaging of the auditory, motor and visual cortices. The results show that the acoustical noise effects on motor and visual responses are opposite. That is, for the motor activity, it shows an increased total motor activation while for the visual stimulation, corresponding(visual) cortical activity has diminished substantially when the subject is exposed to a loud acoustic sound. Although the current observations are preliminary and require more experimental confirmation, it appears that the observed acoustic-noise effects on brain functions, such as in the motor and visual cortices, are new observations and could have significant consequences in data observation and interpretation in future fMRI studies.

• Journal of the Korean Home Economics Association
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• 제35권5호
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• pp.213-219
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• 1997

The purpose of this study is to propose a model for evaluating comfort of indoor environment based on residents' subjective respones. The questionnaire survey was given to the residents at apartment complex located in Ilsan, Kyunggi-Do. The following are the results obtained in this thesis. The results of path analysis on comfort revealed that direct effects to comfort were the satisfaction on thermal environment, indoor air environment and sound environment, and the cognition on indoor air environment and sound environment. An evaluation formula of comfort by the factors of direct effects was given. This formula is recommended to evaluate comfort for pp.O.E(post occupancy evaluation)by residents.

• The Korean Journal of Pesticide Science
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• 제14권4호
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• pp.415-420
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• 2010

This study investigated effects of different sound frequencies on development and insecticide susceptibility of the green peach aphid, Myzus persicae. Under a constant sound intensity (95 dB), different frequency (0-5,000 Hz) sounds were treated on entire developmental period of the aphids. With increase of sound frequencies, nymphal to adult development of the aphids showed significant retardation and the females exhibited a significant decrease in fecundity. The greatest disrupting effects were induced by treatment of 5,000 Hz, which also caused marked change in protein expression of the aphids analysed by two dimensional electrophoresis. Sound frequencies above 2,000 Hz significantly increased susceptibility of the aphids against imidacloprid. This study clearly suggest that there is a stress sound, which can be sensed by M. persicae and induces its physiological alteration.

• Phonetics and Speech Sciences
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• 제12권4호
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• pp.9-17
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• 2020

Changes in the first language (L1) sound system as a result of acquiring a second language (L2) (i.e., phonetic drift) have received considerable attention from a variety of speakers, settings, and environments. Less attention has been given to phonetic drift in adult speakers' L2 learning as their length of residence in America (LOR) increases. This study examines the effects of LOR on voice onset time (VOT) in L1 Korean stops. Three different groups of Korean adult learners of L2 English were compared to assess how malleable their L1 representations are in terms of LOR and whether there is any relationship between L1 change and L2 acquisition. The results showed that the effect of LOR was linguistically unimportant in the production of Korean stops. However, VOT merger as evidence of sound change in Korean stops were robust in the speech production of most of the female speakers across the groups. The results suggest that L2 English may not be the primary cause of L1 sound change. For generalizability, further study is necessary to see whether other acoustic cues show a similar pattern.