• 대한의용생체공학회:의공학회지
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• 제19권1호
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• pp.59-68
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• 1998

디지털 보청기는 기존의 아날로그 보청기에 비하여 많은 장점이 있다. 디지털 신호처리 프로세서의 발달과 더불어 최근에 다양한 디지털 보청 알고리즘과 완전한 디지털 보청기가 선보였다. 디지털 보청기의 알고리즘을 개발하거나 디지털 보청기를 새로이 평가하려는 사람들에게 난청자를 대상으로 하는 임상연구는 필수적으로 거쳐야 하는 과정이다. 그러나 이러한 임상연구는 실제 난청자를 대상으로 하여야 하기 때문에 난청자와 검사자 간에 통상적으로 많은 시간과 노력이 필요하며 원활한 의사 소통이 때로는 어려울 수 있다. 왜냐하면 난청자들의 연령이 너무 어리거나 많아서 의사소통에 지장을 주거나 검사자가 필요로 하는 시간에 비슷한 난청 유형을 가진 대상자를 모으기 어렵다. 본고에서는 임상연구를 보조하여 디지털 보청기 또는 알고리즘이 개발되기까지 수행되어야 할 많은 임상연구의 결과를 예측하고 평가할 수 있는 디지털 난청 시뮬레이션 방법을 제안하고, 실제 환자의 데이터를 사용한 시뮬레이션과 그에 대한 임상 실험을 통하여 시스템의 성능을 평가하였다. 실험 결과, 정상인으로부터 모델링된 환자 데이터와 매우 유사한 측정 결과를 얻어냄으로써, 제안된 시스템이 목적하고자 하는 바를 이룰 수 있음을 검증하였다. 또한 난청 시뮬레이터의 목적인 디지털 보청기 알고리즘을 개발하기 위한 평가 툴로서, 개발 초기에 다양한 디지털 보청기용 알고리즘을 구현하여 실제 난청 시뮬레이터와 연계하여 실험함으로써 보청기 알고리즘의 평가 및 새로운 보청기 알고리즘을 개발하고 평가하거나 향후 난청자를 대상으로 하는 임상연구에서 사용할 수 있는 유용성을 입증하였다.로 우유 교육 프로그램이 향후보다 체계적이고 확대되어 지속적으로 실시된다면, 우유에 대한 의미는 물론 인식 그리고 지식 정도에 있어 효과적인 결과를 유도할 수 있을 것이다.니하였다. 6) Dibutyryl cyclic AMP 및 8-bromo cyclic GMP 모두 혈소판응집률(血小板凝集率)을 감소시켰고, 후자(後者)는 전자(前者)에 비(比)하여 월등(越等)히 현저(顯著)하였다. sodium nitroprusside에 의한 항응집률(抗凝集率)은 methylene blue 전처치(前處置)에 의하여 길항(拮抗)되었으나, bovine hemoglobin전처치에 의하여는 영향(影響)을 받지 아니하였다. 이상(以上)의 성적(成績)을 종합(綜合)하면, 뇌졸중증(腦卒中症)때, 특히 뇌혈전증(腦血栓症)의 응급치료시(應急治療時) sodium nitroprusside의 응용(應用)이 가능(可能)하다고 사료(思料)되며, 이에 대(對)하여 임상적(臨床的) 치료(治療)가 기대되는 바이다.다시 상승(上昇)하는 경향(傾向)이었다. 중성지질(中性脂質) 중(中) climacteric rise 및 숙도(熟度)와 관련하여 변화(變化)한 것은 diglyceride 및 sterol ester의 2종(種)이었으며 glyceride가 중성지질(中性脂質) 전량(全量)의 변화(變化)와 동일(同一)한 경향(傾向)인데 반(反)하여 sterol ester은 climactric onset까지 증가(增加)하다가 기후(其後) 감소(減少)하였다. 인지질(燐脂質)도 저장기간(貯藏期間) 중(中) 처리구(處理區)에 관계(關係)없이 다같이 감소(減少)되었는데, 그 정도(程度)

• 한국음향학회지
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• 제24권7호
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• pp.379-386
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• 2005

최근까지 개발되었던 청각 보조기 중에서 공기 전도형 보청기의 하울링 (howling) 현상과 수술 후 이소골 등 기존 음향계의 재생이 불가능한 인공 와우 (cochlear implant system)의 단점을 해결하고, 동시에 청음 명료도가 높은 음성 신호를 전달하기 위한 수단으로 연구된 것이 인공중이 (implantable middle ear hearing device) 이다. 본 연구에서는 인공중이의 음성 신호 재현을 위한 진동 장치인 차동전자 트랜스듀서 (differential electromagnetic transducer, DET)에 대한 수학적 모형화와 계의 진동을 기술하는 운동방정식을 유도하고 그 해를 구하였다. 제한된 크기와 인가 전류 $1\;mA_{rms}$ 정현파에서 최대 구동력을 얻기 위해서 전자기력에 대한 유한요소해석을 수행하였고, 결과에 의해서 자석과 코일에 대한 최적 크기를 결정하였다. 사람의 중이 내 등자뼈 (stapes)의 진동 특성과 유사한 진동을 갖는 DET를 설계하기 위해서, 진동막의 강성계수를 변화하면서 진동해석을 시뮬레이션 하였다. 설계된 DET는 마이크로 머시닝 기술에 의해서 제작하였고, 그 진동 특성을 측정 하였다. 최종적으로 측정된 진동 특성에 대한 분석을 통하여 인공중이를 위한 진동 장치로서의 적용 가능함을 확인하였다.

• Journal of Audiology & Otology
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• 제24권1호
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• pp.40-47
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• 2020

Because the psychophysical symptoms of hearing loss and dementia in the elderly are very similar, untrained healthcare professionals in dementia facilities can easily overlook a severity of hearing loss in their patients. The present study identifies their knowledge, attitudes, and practices (KAP) on hearing loss using a survey whether they may help hearing problem of the patients with dementia. A total of 29 health-care professionals responded to the KAP survey. Also, 2 family members participated. The results showed that most of the nurses and caregivers in elderly medical welfare facilities who worked with dementia patients did not have knowledge of their hearing loss. Even the facility managers did not know how to conduct hearing tests for their patients although they did recognize that some of their patients had a hearing loss. Eventually, actual practice was not possible at this moment by the professionals. However, our respondents did have a positive attitude toward screening for hearing loss and help their patients with dementia wear hearing aids if a clinical guideline was provided. We suggest to develop clear and precise clinical guidelines of the hearing screening test for the dementia patients due to the interrelationship between dementia and hearing loss. When these guidelines apply to elderly residents in a medical welfare facility, early diagnosis and treatment of their sensory loss will help alleviate their dementia as well.

• 대한청각학회지
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• 제24권1호
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• pp.40-47
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• 2020

Because the psychophysical symptoms of hearing loss and dementia in the elderly are very similar, untrained healthcare professionals in dementia facilities can easily overlook a severity of hearing loss in their patients. The present study identifies their knowledge, attitudes, and practices (KAP) on hearing loss using a survey whether they may help hearing problem of the patients with dementia. A total of 29 health-care professionals responded to the KAP survey. Also, 2 family members participated. The results showed that most of the nurses and caregivers in elderly medical welfare facilities who worked with dementia patients did not have knowledge of their hearing loss. Even the facility managers did not know how to conduct hearing tests for their patients although they did recognize that some of their patients had a hearing loss. Eventually, actual practice was not possible at this moment by the professionals. However, our respondents did have a positive attitude toward screening for hearing loss and help their patients with dementia wear hearing aids if a clinical guideline was provided. We suggest to develop clear and precise clinical guidelines of the hearing screening test for the dementia patients due to the interrelationship between dementia and hearing loss. When these guidelines apply to elderly residents in a medical welfare facility, early diagnosis and treatment of their sensory loss will help alleviate their dementia as well.

• Clinical and Experimental Pediatrics
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• 제50권1호
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• pp.7-13
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• 2007

Hearing loss in newborns is the most frequently occurring birth defect. If hearing impaired children are not identified and managed early, it is difficult for many of them to acquire the fundamental language, social and cognitive skills that provide the foundation for later schooling and success in society. All newborns, both high and low risk, should be screened for hearing loss in the birth hospital prior discharge (Universal Newborn Heaing Screening, UNHS). Objective physiologic measures must be used to detect newborns and very young infants with hearing loss. Recent technological developments have produced screening methods and both evoked otoacoustic emission (EOAE) and auditory brainstem response (ABR) have been successfully implemented for UNHS. Audiologic evaluation should be carried out before 3 months of age and infants with confirmed hearing loss should receive intervention before 6 months of age. All infants who pass newborn hearing screening but who have risk indicators for other auditory disorders and/or speech and language delay receive ongoing audiologic surveillance and monitoring for communication development. Infants with sensorineural hearing loss are managed with hearing aids and receive auditory and speech-language rehabilitation therapies. Cochlear implants can be an outstanding option for certain children aged 12 months and older with severe to profound hearing loss who show limited benefit from conventional amplifications.

• 전기전자학회논문지
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• 제14권1호
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• pp.47-54
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• 2010

본 연구에서는 잡음환경에서 디지털 보청기의 잡음제거를 위해 2,3,4,5개의 마이크로폰을 이용해 잡음제거를 하고 비교 분석 하였다. 실제 디지털 보청기에서 사용할 수 있게 하기 위해 귀걸이형 (behind-the-ear type, BTE) 보청기의 형태와 유사하게 마이크로폰을 배열한 실험 세트를 구성하여 각각의 조건에 따라 신호녹음을 하였고, 녹음된 각각의 신호들을 멀티 마이크로폰을 이용한 잡음제거 알고리즘으로 잡음 제거하였다. 평가 방법에 따라 잡음제거 전과 후의 SNR (Signal to Noise Ratio)과 PESQ (Perceptual Evaluation of Speech ) 측정 분석 결과 마이크로폰 3개와 4개를 사용하였을 때 가장 높은 성능 향상을 보였으며 대부분의 경우에서 마이크로폰의 개수가 늘어남에 따라 성능이 향상된 것을 확인하였다.

• 대한음성학회지:말소리
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• 제52호
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• pp.49-60
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• 2004

The purpose of this paper was to evaluate the effect of hearing level on fundamental frequencies in children. Participants totaled sixty children divided by three groups: congenitally deafened children with cochlear implantation(CI), congenitally deafened children with hearing aids(HA), and children with normal hearing(NH). Fundamental frequencies were measured during the sustained phonation of a vowel /a/. There was statistically significant difference of fundamental frequencies across the groups(p<.01). In post hoc analysis, HA and NH group showed statistically significant difference, but CI group didn't showed significant differences with two groups. In correlation analysis between F0 and the chronological age, there were significant negative tendencies in CI and NH group, but not in HA group. The characteristics of fundamental frequency in CI group were found similar to NH group than HA group in this study. Therefore the results of this study suggest that the hearing level is one of the influencing factors to the fundamental frequency of children.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.755-758
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• 2004

A hearing aid performs the role of fitting in order to provide those with a hearing problem with a better hearing ability in ordinary circumstances. The existing Fitting system in the hearing aid is consisted somewhat complex, and simply performs the role of Fitting without any supervisions of those with a hearing problem. Such is these methods makes it unable to establish an organized supervision, and shows a problem in making high efficiency. In order to solve this problem mentioned as above, the based thesis have connected the Fitting program and the patient-management database program for the easy use by the user.

• 한국멀티미디어학회논문지
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• 제19권2호
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• pp.375-385
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• 2016

Recently, several implantable hearing aids such as cochlear implant, middle ear implant, etc., which have a module receiving power and signal from outside the body, are frequently used to treat the hearing impaired patients. Most of implantable hearing aids are adopted permanent magnet pairs to couple between internal and external devices for the enhancement of power transmission. Generally, the internal device which containing the magnet in the center of receiving coil is implanted under the skin of human temporal bone. In case of MRI scanning of a patient with the implantable hearing aid, however, homogeneous magnetic fields of the MRI might be interfered by the implanted magnet. For the above reasons, the MR image is degraded by large area of artifact, so that diagnostics are almost impossible in deteriorated region. In this paper, we proposed an external coil system that can reduce the artifact of MR image due to the internal coupling magnet. By finite element analysis estimating area of MR artifact according to varying current and shape of the external coil, optimal coil parameters were extracted. Finally, the effectiveness of the proposed external coil system was verified by confirming the artifact at real MRI scan.

• Journal of Audiology & Otology
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• 제25권2호
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• pp.72-79
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• 2021

Background and Objectives: The speech-in-noise test is typically performed using an audiometer. The results of the digit-in-noise recognition (DIN) test may be influenced by the flat frequency response of free-field audiometry and frequency of the hearing aid fit based on fitting rationale. This study aims to investigate the DIN test in unaided and aided conditions. Subjects and Methods: Thirty four adults with moderate and severe sensorineural hearing loss (SNHL) participated in the study. The signal-to-noise ratio (SNR) for 50% of the DIN test was obtained in the following two conditions: 1) the unaided condition, performed using an audiometer in a free field; and 2) aided condition, performed using a hearing aid with an unvented individual earmold that was fitted based on NAL-NL2. Results: There was a statistically significant elevation in the mean SNR for the severe SNHL group in both test conditions when compared with that of the moderate SNHL group. In both groups, the SNR for the aided condition was significantly lower than that of the unaided condition. Conclusions: Speech recognition in hearing-impaired patients can be realized by fitting hearing aids based on evidence-based fitting rationale rather than by measuring it using free-field audiometry measurement that is utilized in a routine clinic setup.