• 한국노년학
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• v.37 no.1
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• pp.1-14
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• 2017

The purpose of this study was to examine the effect of vision and hearing limitation on the onset of disability among Korean elderly with the consideration of social participation and depression. Study population consisted of 2,670 people aged 65 and above who participated in both the 1st(2006) and 2nd(2008) wave of the Korean Longitudinal Study of Aging(KLoSA), and also reported no ADL or IADL disability in 2006. As the results, first, it found that vision and hearing limitation, social participation, and depression were significant risk factors for the onset of IADL disability in unadjusted analysis. After multivariable adjustment, however, only vision limitation showed significant association with the onset of IADL disability. Second, in the logistic analysis with four categorized variables(vision/hearing limitation + social participation, vision/hearing limitation + depression), the elderly who had vision or hearing limitation had a significantly 1.7 times higher odds ratio for disability onset if they also had low social participation compared with those who had no vision or hearing limitation, and high social participation. Whereas, depression was not significantly associated with the relationship between vision or hearing limitation, and disability onset. The study suggests that the intervention program developed to prevent social isolation of older people with vision or hearing limitation, may be helpful to reduce and postpone the risk of disability onset as well as early detection and treatment of vision or hearing problems.

• Journal of Biomedical Engineering Research
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• v.37 no.6
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• pp.209-214
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• 2016

Binaural hearing aids with a voice transmitter have been widely used to enhance sound quality in noisy environment. However, this system has a limitation on sound-source localization. In this study, we investigated automatic directional-gain control method using geomagnetic sensors to provide directional information to binaural hearing aid user. The loudness gains of two hearing aids were differently controlled based on the directional information between a speaker position and a viewing direction of hearing aids user. This relative directional information was measured by two geomagnetic sensors on hearing aids user and a speaker. The results showed that the loudness gains were accurately controlled and could provide directional information based on the cue of interaural level differences.

• The Journal of Korean Association of Computer Education
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• v.18 no.4
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• pp.11-18
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• 2015

A person with defects and the lack of hearing, has very difficult problems to listen to the sound of conversation or environment, and these problems cause wrong directions in the linguistic sense and character. We designed and implemented an application to practice and correct pronunciation of a hearing-impaired person specially. This is made as a mobile app without the limitation of time and space, and this provides practices with the level of difficulty in learning of pronunciation, taking into consideration of remedial status in pronunciation. The hearing-impaired person can train the basic pronunciation and the word pronunciation. He or she can practice basic skills in pronunciation and check the record on the practice rate and the success rate. Also, the person can improve pronunciation by self-correction function using the front camera of a smart phone.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1744-1749
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• 2013

Acoustic feedback is perceived as whistling or howling, which is a major complaint of hearing-aids users. Acoustic feedback cancellation is important in hearing-aids because acoustic feedback degrades performance of the hearing aid device by reducing maximum insertion gain. Adaptive systems for estimate acoustic feedback path and feedback suppression algorithms have been proposed in order to solve this problem. A typical feedback cancellation algorithm is LMS(least mean squares) because of its computational efficiency. However it has problem of convergence performance in high correlated input signal. In this paper, we propose a new variable step-size normalized LMS(least mean squares) algorithm using VAD(voice activity detection) to overcome the limitation of the LMS algorithm. The VAD algorithm is GSAP(global speech absence probability) and the feedback cancellation algorithm is normalized LMS. The proposed algorithm applies different step-size between voice and non-voice using VAD, for high stability, fast convergence speed and low misalignment when correlated inputs, such as speech. The result of simulation with white noise mixed speech signal, the proposed algorithm shows high performance then traditional algorithm in terms of stability, convergence speed and misalignment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.437-440
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• 2010

In modern society, people will obtain the necessary goods and find meaning of himself and his community through jobs. The meaning of job for people with disabilities is identical with people's with non-disabilities and people with disabilities will live as a member of society through jobs. Because people with hearing impairment have a problem about job such as the short longevity and high turnover, vocational aptitude test which evaluates psychological characteristics, aptitudes and interests is necessary for them. In this paper, we design and evaluate the picture vocational interest inventory supporting the Internet as a vocational aptitude test for people with hearing impairment. We use the picture vocational interest inventory of Korean Employment Development Institute as a implementation target. The previous tests for people with hearing impairment have a problem which an examinee, an examiner and a sign language interpreter are involved in the test at the same space and time. Therefore, our picture vocational interest inventory has no limitation of time and space because it processes on the Internet.

• Journal of Environmental Health Sciences
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• v.34 no.2
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• pp.153-160
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• 2008

Personal noise exposure was assessed in railroad operators working in 40 operation units including the Gyeongbu line, Honam line, and Janghang line between 2004 and 2006. 8-hour TWA were assessed based on the MOL (Ministry of Labor) guideline on noise evaluation, and 17% of these measurements exceeded 85 dBA while 70% were over 80 dBA. When the ACGIH TLV is adopted, 40% of measurements were over TLV (85 dBA). The noise exposure risk of railroad operators was higher for diesel locomotive operation and longer operational distances; in addition, the risk was higher for passenger car operation compared to freight car driving. Given that in Korea, over the past 30 years diesel locomotives have provided most of the railway's motive power and that hearing protective equipment is not likely to be used by workers during operation, railroad operators are at a high risk of noise-induced hearing loss. The result of audiometric test among 568 railroad operators showed that 32.6% of those tested had a hearing threshold shift of more than 40 dB. In conclusion, this study calls for more fundamental measures including noise control countermeasures within the operation areas, development of equipment that generates less noise and adopting limitation on the operation distance for a work shift.

• Phonetics and Speech Sciences
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• v.6 no.1
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• pp.85-93
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• 2014

This paper investigated the effects of frequency band limitation on perceptual characteristics of Korean vowels. Monosyllabic speech (144 syllables of CV type, 56 syllables of VC type, 8 syllables of V type) produced by two announcers were low- and high-pass filtered with cutoff frequencies ranging from 300 to 5000 Hz. Six listeners with normal hearing performed perception tests by types of filter and cutoff frequencies. We reported phoneme recognition rates and types of perception error of band-limited Korean vowels to examine how frequency distortion in the process of speech transmission affect listener's perception.

• Phonetics and Speech Sciences
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• v.6 no.1
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• pp.95-101
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• 2014

This paper investigated the effects of frequency band limitation on perceptual characteristics of Korean consonants. Monosyllabic speech (144 syllables of CV type, 56 syllables of VC type, 8 syllables of V type) produced by two announcers were low- and high-pass filtered with cutoff frequencies ranging from 300 to 5000 Hz. Six listeners with normal hearing performed perception test by types of filter and cutoff frequencies. We reported phoneme recognition rates and types of perception error of band-limited Korean consonants to examine how frequency distortion in the process of speech transmission affect listener's perception. The results showed that recognition rates varied with the following factors: position in a syllable, manner of articulation, place of articulation, and phonation types. Consonants in the final position were stronger to the frequency band limitation than those in the initial position. Fricatives and Affricates are stronger than stops. Fortis consonants were less stronger than their lenis or aspirated counterparts. Types of perception error also varied depending on such factors as consonant's place of articulation: In case of bilabial stops, they were perceived as alveolar stops with while in cases of alveolar and velar stops, there were changes in phonation types without any change in the place of articulation.

• Korean Journal of Social Welfare
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• v.66 no.3
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• pp.55-73
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• 2014

The purpose of this study was to develop and validate Korean version of Deaf Acculturation Scales(DAS). Pilot items were made a faithful translation of the Acculturation Scales of Maxwell-McCaw and Zea (2011) and were modified for Korean Deaf people. The Scale involves two dimensions, in order to measure the acculturation of Deaf people; Deaf acculturation and hearing acculturation. Using factor analysis, we developed a Korean version of DAS consisted of twenty-five items for Deaf acculturation dimension and twenty-five items for hearing acculturation dimension. These analysis supported the four factors of Deaf acculturation dimension and the five factors of hearing acculturation dimension. Reliability, assessed by Cronbach's ${\alpha}$, was .93 for Deaf acculturation and .93 for hearing acculturation, respectively, which confirm the Koran version of DAS. Construct validity was demonstrated through correlation with Deaf acculturation-related variables: age, age of Deafness, Degree of hearing loss, American Sign Language ability, and lip-reading ability. Criterion validity was supported by correlation with Collective Self-Esteem Scale. Limitation and implication of this study and direction for future research were discussed.

• International journal of advanced smart convergence
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• v.5 no.4
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• pp.48-53
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• 2016

In this paper, all elements used in integrated infrastructure for job competency assessments of NCS (National Competency Standards) will be merged into assessment system using multiple devices(ASMD). NCS is a systematic approach on required abilities (knowledge, technical expertise, attitude) to process the tasks in the fields by industry. Competiveness of ASMD design is that no limitation of time and space using personal devices like PC, laptop, smartphone, and tablet, while seeing screen, hearing, touching, speaking, and writing. Question type can be limitless to express the situation. To lead technologies and market for domestic and oversea assessment system, supporting on multiple devices with connectivity that will eliminate limitation of time and space is the key feature for design competitiveness. Design of integrated assessment system proposed in this paper can be applied to NCS, fundamental competency evaluation, online test, job aptitude test, and foreign language test which involve listening, reading, writing, and speaking. Compared with existing evaluation method, reduction of investment and operating cost will be greater. Along with development of ICT technologies, the next generation of integrated assessment system will be quickly changed to ASMD, which already involves connected service between internet and smart devices.