• Journal of the Korean Society for Precision Engineering
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• v.20 no.9
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• pp.151-158
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• 2003

The impulse noise of bullet after shooting in small arms has an effect on the hearing ability of human. Although a silencer has been developed for noise reduction in small arms, there is only a few researches about relationships between the sound pressure level and the auditory sense of human. In this study, the quantitative sound pressure levels are revealed by experimental measurements of impulse noise with each silencer type. And the performance evaluation for noise suppression of a silencer in small arms is carried out to reduce a serious loss of the hearing ability of the small arms user. It is concluded that the evaluated results can be utilized for checking sound pressure and data accumulation for new small arms design with silencer.

• Journal of Biomedical Engineering Research
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• v.19 no.6
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• pp.623-629
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• 1998

To provide sufficient sound to the hearing-impaired person(HIP) who have many difficulty in communication with others using general telephone, big amplification is needed. But big amplification can occur howling as a side effect. In this study we developed the new technique of big amplification without howling, manufactured and estimated the new hearing aid telephone. Telephone speech is divided to three frequency band, amplified respectively and fitted to HIP's hearing ability. The telephone speech frequency is monitored by counter in time domain. The counter transfers the sinusoidal sound to rectangular wave using comparator and counts the number of rectangular wave in a certain time period, that is frequency, to monitor the howling. Telephone have microphone and speaker, which are fitted in a rigid structure and frequency band of telephone sound is limited, so howling occurs in the limited frequency band. If the counter notices that howling conditions happen, microprocessor decreases quickly the gain of the related frequency band. The result of test of our new hearing aid telephone showed that we can amplifiy the sound as much as 40dB, which is meaningful level to many HIP, and make HIP increase their perception ability from 20% to 60.8% in 1 syllable test and from 28.9% to 78% in 2 syllable test.

• Journal of Sensor Science and Technology
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• v.13 no.6
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• pp.479-487
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• 2004

The prevention of noise induced hearing loss is very important, because there is no treatment for it. There are some kinds of devices for hearing protection, and those are effective in preventing a noise induced hearing loss. However, people often resist the use of hearing protection devices because it is difficult to have a conversation. Therefore, a hearing protection device is must effective not only in hearing protection but also in preserving communication ability. In this paper, we proposed a small acoustic filter for ITE type noise protector to solving the problem about the difficulties of conversation. That is applied a principle of acoustic filters that have been used for a muffler of automobiles, guns, and etc. To find out the sound transmission characteristic at the eardrum, we regarded an acoustic filter and external ear canal as a coupled system. So, we simulated the coupled system with OrCad, and experimented with a designed acoustic filter and a 2 cc coupler which has the same transmission characteristic as the external ear canal has. We confirmed that it is possible to adjustment acoustic transmission characteristics through simulation of electrical model for acoustic filter and external ear and experiments using designed small acoustic filters.

• Journal of the Korea Society of Computer and Information
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• v.26 no.12
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• pp.105-110
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• 2021

In this paper, we design and implement an Android mobile application that helps hearing impaired people communicate based on STT(Speech-to-Text) and TTS(Text-to-Speech) APIs and accelerometer sensor of a smartphone. This application provides the ability to record what the hearing-Impairment person's interlocutor is saying with a microphone, convert it to text using the STT API, and display it to the hearing-Impairment person. In addition. In addition, when a hearing-impaired person inputs a text using the TTS API, it is converted into voice and told to the interlocutor. When a hearing-impaired person shakes their smartphone, an accelerometer based background service function is provided to run the application. The application implemented in this paper provides a function that allows hearing impaired people to communicate easily with other people when communicating with others without using sign language as a video call.

• The Journal of the Acoustical Society of Korea
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• v.41 no.1
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• pp.99-107
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• 2022

This study attempted to analyze the consonant perception ability and errors and to verify compatibility items for hearing impaired children wearing hearing aids and cochlear implants using the Phoneme Perception Test for School-Aged children (PPT-S). As a result of the study, it was found that children with hearing impairments have more difficulty in perceiving final consonants than initial consonants. The hard type of PPT-S, in which the articulation method and articulation place of the target and foil words are similar, felt more difficult than the easy type. Among the initial consonants, the incorrect response rate for aspiration sound was higher. In the case of final consonants, the incorrect answer rate for 'ㄷ' and 'ㅁ' was relatively higher. There was no significant difference in the percentage of correct response rate according to the gender of the speaker. The above results can be usefully used as basic data for standardizing of PPT-S and evaluating the intervention effects before and after hearing rehabilitation with hearing impaired children.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.6
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• pp.1381-1388
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• 2013

In order to improve the availability of underwater sound by the fundamental data on the hearing ability, the auditory thresholds for the bambooleaf wrasse pseudolabrus japonicus were determined at 80Hz, 100Hz, 200Hz, 300Hz, 500Hz and 800Hz by heartbeat conditioning method using pure tones coupled with a delayed electric shock. The audible range of the bambooleaf wrasse extended from 80Hz to 800Hz with the best sensitivity around 100Hz and 200Hz. In addition, the auditory thresholds over 300Hz increased rapidly. The mean auditory thresholds of the bambooleaf wrasse at the test frequencies, 80Hz, 100Hz, 200Hz, 300Hz, 500Hz and 800Hz were 100dB, 95.1dB, 94.8dB, 109dB, 121dB and 125dB, respectively. Auditory critical ratios for the bambooleaf wrasse were measured using masking stimuli with the spectrum level range of about 70, 74, 78dB (0dB re $1{\mu}Pa/\sqrt{Hz}$). According to white noise level, the auditory thresholds increased as compared with thresholds in a quiet background noise. The Auditory masking by the white noise spectrum level was stared over about 60dB within 80~300Hz. Critical ratios to be measured at frequencies from 80Hz to 300Hz were minimum 33dB and maximum 39dB.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.4
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• pp.479-486
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• 2012

In order to obtain the fundamental data about the behavior of conger by underwater audible sound, this experiment was carried out to investigate the hearing ability of Conger eel Conger myriaster which was in the coast of Jeju Island by heartbeat conditioning method using pure tones coupled with a delayed electric shock. The audible range of conger eel extended from 50Hz to 300Hz with a peak sensitivity at 80Hz including less sensitivity over 200Hz. The mean auditory thresholds of conger eel at the frequencies of 50Hz, 80Hz, 100Hz, 200Hz and 300Hz were 105dB, 92dB, 96dB, 128dB and 140dB, respectively. The positive response of conger eel was not evident after the sound projection of over 200Hz. At the results, the sensitive frequency range of conger eel is narrow in spite of swim bladder. Auditory masking was determined for Conger eel by using masking stimuli with the spectrum level range of about 60~70dB (0dB re $1{\mu}Pa/\sqrt{Hz}$). According to white noise level, the auditory thresholds increased as compared with thresholds in a quiet background noise including critical ratio at 68dB of white noise from minimum 26dB to maximum 30dB at test frequencies of 80Hz and 100Hz. The noise spectrum level at the start of masking was distributed at the range of about 68dB within 80~100Hz.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.173-174
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• 1998

We developed the high power telephone for hearing impaired person (HIP) who can't communicate with others by general telephone. The general telephone can't delivered enough sound for HIP to understand telephone speech. In this study, we developed the method of telephone speech amplification proper to HIP and effective howling suppression which occurred as a side effect of amplification. In our new telephone, speech sound is divieded to 3 band pass filter path, amplified respectively fit to HIP's hearing ability, and monitored howling in time domain. The result of test of our telephone showed that we can amplify the sound as much as 40dB, which is very useful to HIP, and make HIP increase the perception of telephone speech.

• The Journal of Korean Academy of Sensory Integration
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• v.12 no.1
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• pp.1-11
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• 2014

Objective : The purpose of this research is understanding relevancy of school ages'ability of sensory process and preference of what they want to play, and studying of main reason of impact of sensory process to preference of what school ages want to play. Methods : During 22 to 24 October 2012, our group evaluated and analyzed ability of sensory process and preference of what children want to play by using Short Sensory Profile (SSP) and Pediatric Interest Profile (PIP) to elementary school children in fourth grade at Kimhae city in Kyungnam province. Results : For the total population of an ability of sensory process and frequency, preference, and proficiency of eight different games, preference of outdoor activities appears to be related to total score of sensitivity to taste and smell and filter of hearing. For preference and proficiency of creative activities appears to be related to sensitivity of taste and smell. Preference of lessons and classes related to total scores of sensitivity of tactile sensation, taste and smell, movement, and filter of hearing, and sensitivity of visual and hearing. Frequency and proficiency of lessons and classes are inter-related to sensitivity of visual and hearing. Conclusion : This research shows that there is no inter-relationship between function of sensory process and preference of what children want to play, however certain games relevantly show the inter-relationship. The research provides the basic data of what the preference of what children want to play and determine what children can play during occupational therapy with plays after studying inter-relationship of school ages'ability of sensory process and games.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.240-242
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• 1996

In this paper, we proposed a method of a hearing aid suitable for the sensorineural hearing impaired. Generally as the sensorineural hearing impaired have narrow audible ranges between threshold and discomfortable level, the speech spectrum may easily go beyond their audible range. Therefore speech spectrum must be optimally amplified and compressed into the impaired's audible range. The level and frequency of input speech signal are varied continuously. So we have to make compensation input signal for frequency-gain loss of the impaired, specially in the frequency band which includes much information. The input sigaal is divided into short time block and spectrum within the block is calculated. The frequency-gain characteristic is determined using the calculated spectrum. The number of frequency band and the target gain which will be added input signal are estimated. The input signal within the block is processed by a single digital filter with the calculated frequency-gain characteristics. From the results of monosyllabic speech tests to evaluate the performance of the proposed algorithm, the scores of test were improved.