• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.1021-1026
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• 2000

The thermal characteristics of high-speed air spindle system with built-in motor are studied. Experiment and finite element method analysis obtain temperature rise and temperature distribution of housing. For the analysis three-dimensional model is built and temperature rise and distribution in thermal steady state are computed for each rotational frequency. Generally. It is said that the heat generation of air bearing is negligible. But it is certain that the heat generation of air bearing can not be negligible especially in high-speed conditions Frequency response test for air spindle system is executed. In case that the heat generation of air spindle system is high, natural frequency of the system becomes lower when it reaches thermal steady-state and it means that the stiffness of air hearing becomes smaller due to the change of bearing clearance. It is shown that the temperature rise of all spindle system causes thermal expansion md induces the variation of hearing clearance. In consequence the st illness of air bearing becomes smaller.

• 한국소음진동공학회논문집
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• 제19권9호
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• pp.928-934
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• 2009

Underwater impulsive sound such as underwater blasting noise, piling noise and stone breaking hammer affects marine animal hearing response and organs. This study describes the characteristics of various impulsive noise from waterfront construction site and their effect on fish. Time constant, peak pressure, energy and SEL(sound exposure level) of four different underwater impulsive sounds are quantified. Auditory and non-auditory tissue damage ranges are derived by comparing their quantities to the exposure criteria for fish. Damage ranges of auditory tissue and non-auditory tissue of underwater boring blast of 150 kg of charge, are about 100 m and 300 m, respectively. Other three impulsive sounds also gives damage effects but less than that of underwater boring blast.

• 한국산학기술학회논문지
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• 제22권4호
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• pp.430-440
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• 2021

본 연구는 난청 고령자의 우울정도, 인지기능, 의사소통능력 및 정량뇌파를 분석하고, 관련성을 규명할 목적으로 시도하였다. Y 시 소재의 S 청능재활 센터를 내원한 60세 이상의 난청 고령자 중 모집공고문을 통해 남성 37명, 여성 26명이 2020년 6월 20일부터 2020년 9월 3일까지 자발적으로 참여했다. 구조화된 설문지를 통해 대상자의 전반적인 특성, 우울정도, 인지기능을 평가하였다. 의사소통능력의 척도인 단어인지도는 한국표준 단음절어를 사용하여 진단용 청력검사기로 평가하였다. 정량뇌파는 전전두엽 Fp1과 Fp2에 건식 전극을 사용하여 2채널 뇌파 측정기로 측정하였다. 수집된 자료는 SPSS/WIN 25.0 프로그램으로 인구 사회학적 특성 파악을 위한 빈도분석, 변수간 Pearson's correlation분석, 3분할 집단 간 One-way ANOVA분석을 하였다. 결과를 요약하면 다음과 같다. 의사소통능력은 전전두엽 좌우 대칭성(**p<.01)과 정(+)적 상관관계를 보였고, 우뇌 정신적 산만 및 스트레스(*p<.05)와 부(-)적 상관관계를 보였다. 그러나 우울정도와 인지기능과는 유의한 상관관계는 없었다. 의사소통능력에 따른 3분할 집단별 차이 검정에서도 전전두엽 좌우 대칭성(**p<.01)이 우울정도와 인지능력보다 높은 수준의 상관관계를 보였다. 이상의 결과는 정량뇌파에서 측정된 전전두엽 좌우 대칭성이 난청 고령자의 의사소통능력의 강력한 생체적 지표 가능성을 시사 하였다.

• 센서학회지
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• 제18권4호
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• pp.286-293
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• 2009

The implantable middle ear hearing devices(IMEHDs) have been developed to overcome the conventional hearing aid's problem(ringing effect caused by the acoustic feedback, cosmetic problem, etc.). In the IMEHDs, the vibrating transducer is a key component because its vibration enables to hear for hearing impaired people. The vibrating transducer is implanted on ossicular chain by surgical operation. The coupling status between implanted transducer and ossicular chain has an effect on delivering vibrating force from transducer to stapes. Noninvasive method is required to investigate the output characteristics of IMEHDs after implementation. Recently, emitted sound pressure measuring method of tympanic membrane is proposed to investigate the output characteristics of IMEHDs. However, the relationship between displacement of stapes and sound pressure by tympanic membrane was not cleared. In this paper, displacement of stapes and sound pressure by tympanic membrane were measured using the differential floating mass transducer(DFMT) that implanted on the ossicular chain of the human temporal bone and physical ear model. Through the experiments results, the relationship between displacement of stapes and sound pressure by tympanic membrane was investigated.

• 전기학회논문지
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• 제60권6호
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• pp.1196-1203
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• 2011

The reduced frequency selectivity is a typical phenomenon of sensorineural hearing loss. In this paper, we compared two modeling methods for reduced frequency selectivity of hearing impaired people. The two models of reduced frequency selectivity were made using LPC(linear prediction coding) algorithm and bandwidth control algorithm based on ERB(equivalent rectangular bandwidth) of auditory filter, respectively. To compare the effectiveness of two models, we compared the result of PESQ (perceptual evaluation of speech quality) and LLR(log likelihood ratio) using 36 Korean words of two syllables. To verify the effect on noise condition, we mixed white and babble noise with 0dB and -3dB SNR to speech words. As the result, it is confirmed that the PESQ score of bandwidth control algorithm is higher than the score of LPC algorithm, on the other hands, and the LLR score of LPC algorithm is lower than the score of bandwidth control algorithm. It means that both non-linearity and widen auditory filter characteristics caused by reduced frequency selectivity could be more reflected in bandwidth control algorithm than in LPC algorithm.

• 수산해양기술연구
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• 제53권1호
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• pp.19-40
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• 2017

A scientific and objective sound exposure criterion for underwater sound damage on fish has been required since there has been many disputes between an underwater sound maker and a fish damage receiver. The existing criteria are still incomplete scientifically owing to a degree of variability of underwater sounds, diversity of fish hearing sensitivity and damage types, etc. This study reviews existing studies on a hearing mechanism of fish species, manmade underwater sound characteristics and sound exposure assessment parameters, and recent sound exposure criteria. A governing equation for damage coverage estimation and damage coverage dependency on sound source level, ambient noise and transmission loss are also reviewed and interpreted based on sound exposure environments. The foreign and Korean (National Environmental Dispute Medication Commission) criteria are reviewed and compared based on scientific aspects. In addition, the deficit and limit of Korean criteria are presented. The objective of this study is to give a direction for related researches and legislation of sound exposure criteria on fish.

• 한국음향학회지
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• 제6권1호
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• pp.58-65
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• 1987

현재 국내에서 사용되고 있는 교환기의 주요 가청신호음인 발신음. 화중음 및 호출음은 CCITT권고에 합당하지 않은 경우가 있고, 합척음인 경우 협화가 이루어지지 않아 청각적인 쾌미감을 갖지 못하며, 또한 교환기종마다 서로 상의한 신호음을 사용함으로써 전화가입자 혼동의 우려가 있으므로, 가청신호음을 새로이 통일할 필요가 있다. 본 논문에서는 CCITT권고 Q35와 청감의 쾌미감을 고려한 새로운 가청신호음을 제안한다. 제안된 가청신호음은 주파수를 400Hz 단일음으로 하고, 각 신호음 사이에 독특한 단속주기를 주어 구별할 수 있도록 하였으며 신호음은 디지탈 교환망에서도 사용이 가능하도록 신호음을 ROM방식으로 발생시키는 방법을 제시한다.

• 음성과학
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• 제5권1호
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• pp.167-179
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• 1999

The hearing mechanism is a complicated system. Sound is generated by a source that sends out air pressure or power. The pressure or power makes the sound waves. These waves reach the eardrum, or tympanic membrane, which vibrates at a rate and magnitude proportional to the nature of the sound waves. The tympanic membrane transforms this vibration into the mechanical energy in the middle ear, which in turn converts it to the hydraulic energy in the fluid of the inner ear. The hydraulic energy stimulates the sensory cells of the inner ear which send neuroelectrical impulses to the central auditory nervous system. The passive perception of auditory information starts just here. The listener gives attention to the speech sound, differentiates the sound from background noise, and integrates his experience with similar sounds. The listener then puts all of these aspects of audition into the context of the moment to identify the nature of sound. This has a major role in human communication. This paper provides an overview of the nature and characteristics of sound, the structure and function of the auditory system, and the way in which sound is processed by the auditory system.

• 한국멀티미디어학회논문지
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• 제21권7호
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• pp.745-754
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• 2018

Language is an essential tool for verbal and emotional communication among human beings, enabling them to engage in social interactions. Although a majority of hearing-impaired people can speak; however, they are unable to receive feedback on their pronunciation most of them can speak. However, they do not receive feedback on their pronunciation. This results in impaired communication owing to incorrect pronunciation, which causes difficulties in their social interactions. If hearing-impaired people could receive continuous feedback on their pronunciation and phonation through lip-reading training, they could communicate more effectively with people without hearing disabilities, anytime and anywhere, without the use of sign language. In this study, the mouth area is detected from videos of learners speaking monosyllabic words. The grayscale information of the detected mouth area is used to estimate a velocity vector using Optical Flow. This information is then quantified as feature values to classify vowels. Subsequently, a system is proposed that classifies monosyllables by algebraic computation of geometric feature values of lips using the characteristics of articulatory phonation. Additionally, the system provides feedback by evaluating the comparison between the information which is obtained from the sample categories and experimental results.

• 치위생과학회지
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• 제10권4호
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• pp.273-278
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• 2010

This study surveyed people with hearing impairments and speech defect living in an area of Gyeonggi-do using a self-administered questionnaire and interviewed them with a deaf interpreter's help during the period from January 21 to February 14, 2009 in order to investigate their oral health management attitude according to their general characteristics. The difference between males and females was statistically significant. The results of this study were as follows. 1. As to the number of times of tooth brushing according to gender, 62.5% of males and 34.2% of females brushed their teeth 2 times, and 25.0% and 35.4% 3 times. 2. As to experiences in scaling according to Academic qualification, those with high academic qualification had scaling more regularly 3. As to tooth brushing methods according to cohabitant, the rolling method was most common regardless of cohabitant. As to the number of times of tooth brushing according to residence type, 41.9% of those living with their parents brushed their teeth 3 times, and 69.2% of those living alone and 47.5% of married ones 2 times. 4. With regard to how to access oral hygiene management education, 81.1% of elementary school graduates used multimedia materials and sign language explanation and captions, 48.6% of middle school graduates used multimedia materials and sign language explanation and 14.3% multimedia materials and captions, 50.0% of high school graduates used multimedia materials and sign language explanation and 17.3% multimedia materials and captions. The parish for the buccal cavity hygiene managements of the hearing impairments speech defect and Development of an educational program are needed.