• 대한의용생체공학회:의공학회지
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• 제30권1호
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• pp.94-102
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• 2009

In this paper, we propose a hearing impairment simulator considering reduced frequency selectivity of the hearing impaired, and verify it's performance through experiments. The reduced frequency selectivity was embodied by spectral smearing using linear prediction coding(LPC). The experiments are composed of 4 kinds of tests; pure tone test, speech reception threshold(SRT) test, and word recognition score(WRS) test without spectral smearing and with spectral smearing. The experiments of the hearing impairment simulator were performed with 9 subjects who have normal hearing. The amount of spectral smearing was controlled by LPC order. The percentile score of WRS test without smearing is $89.78{\pm}2.420%$. The scores of WRS with 24th LPC order and with 8th LPC order are $88.00{\pm}3.556%$ and $83.78{\pm}2.123%$ respectively. It is verified that WRS score is lowered by decreasing LPC order. This is a reasonable result considering that spectral smearing is getting heavier according to decreasing LPC order. It is confirmed that spectral smearing using LPC simulates the reduced frequency selectivity of the hearing impaired and affects the clearness of speech reception.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1664-1675
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• 2021

In order to verify the statistical performance of the nonparametric tests used in the MARSSIM approach, all plausible contamination distribution types that can be encountered in a survey area should be investigated. As the first of such investigations, this study aims to perform the verification for normal distribution of the contamination in a survey area by simulating the collection of random samples from it through the Monte Carlo simulation. The results of the simulations conducted for a total of 81 simulation cases showed that Sign test and WRS test both exhibited an excellent statistical performance: 100% for the former and 98.8% for the latter. Therefore, in final status surveys of the MARSSIM approach, a high statistical performance can be expected in applying the nonparametric hypothesis tests to survey areas whose net contamination can be assumed to be normally distributed.

• 한국직업건강간호학회지
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• 제26권4호
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• pp.207-217
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• 2017

Purpose: This study aimed to evaluate the workplace response system (WRS) against infectious disasters (IDs) based on the response attitudes and capacity of occupational health nurses (OHNs) who worked during the 2015 Middle East Respiratory Syndrome (MERS) outbreak in South Korea. Methods: Fifty-one participants who had worked as OHNs at the time of the 2015 MERS outbreak were surveyed from November 20 to December 10, 2016. Data were collected using a self-report questionnaire and analyzed using descriptive statistics and McNemaer's test. Results: According to the survey results, the following were lacking in the WRS: a dedicated ID-response team, manuals, related education programs for OHNs, and health education programs for workers. Results also confirmed that workers were vulnerable to new infectious diseases because of the lack of health checkups and support for workers before and after business trips abroad. Among the respondents, 98.0% answered affirmatively that an ID was important for health management in the workplace, but 64.7% answered that it was difficult to manage an ID. The perceived capacity items to respond to IDs ranged from 3.0 points to 3.3 points. This scores were generally high. Conclusion: As the WRS is currently insufficient, it is necessary to develop an adequate WRS to IDs by addressing the identified problems.

• 전기학회논문지
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• 제59권4호
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• pp.831-840
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• 2010

In this paper, we propose a hearing impairment simulator considering reduced frequency selectivity and asymmetrical auditory filter of the hearing impaired, and we verified the reduced frequency selectivity and asymmetrical auditory filter affected in speech perception through experiments. The reduced frequency selectivity has made embodied by spectral smearing using LPC(linear prediction coding). The shapes of auditory filter are asymmetrical different with each center frequency. Hearing impaired person which has hearing loss was differently changed with that of normal hearing people and it has different value for speech of quality through auditory filter. The experiments confirmed subjective test and objective test. The subjective experiments are composed of 4 kinds of tests: pure tone test, SRT(speech reception threshold) test, and WRS(word recognition score) test without spectral smearing, and WRS test with spectral smearing. The experiment of the hearing impairment simulator was performed from 9 subjects who have normal ears. The amount of spectral smearing was controlled by LPC order. The asymmetrical auditory filter of proposed hearing impairment simulator was simulated and then some tests to estimate the filter's performance objectively were performed. The objective experiment as simulated auditory filter's performance evaluation method used PESQ(perceptual evaluation of speech quality) and LLR(log likelihood ratio) for speech through auditory filter. The processed speech was evaluated objective speech quality and distortion using PESQ and LLR value. When hearing loss processed, PESQ and LLR value have big difference according to asymmetrical auditory filter in hearing impairment simulator.

• International Journal of Aeronautical and Space Sciences
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• 제6권1호
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• pp.44-51
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• 2005

To provide more accurate and reliable positioning and timing services to Korean nationwide users, the Ministry of Maritime Affairs and Fisheries of Korea is implementing Korean NDGPS (Nationwide DGPS), which is operational partly. And it also has a plan to construct WADGPS (Wide Area Differential GPS) system using sites and equipments of the NDGPS reference stations. For that, Seoul National University GNSS Laboratory is implementing and testing prototypes of WRS (Wide-area Reference Station) and WMS (Wide-area Master Station). Until now, because there are not enough installed WRSs to be used for computing wide area correction information, we cannot test algorithms of WMS with the data processed actually in WRSs. Therefore to evaluate the performance of the algorithms, we made a MATLAB program which can process RINEX (Receiver INdependent Exchange) format data with WADGPS algorithm. Using that program which consists of WRS, WMS and USER modules, we processed the data collected at NDGPS reference stations, which are saved in RINEX format. In WRS module, we eliminate the atmospheric delay error from the pseudorange measurement, smooth the measurement by hatch filter and calculate pseudorange corrections for each satellite. WMS module collects the processed data from each reference stations to generate the wide area correction information including estimated satellite ephemeris errors, ionospheric delays at each grid point, UDRE (User Differential Range Error), GIVE (Grid Ionosphere Vertical Error) and so on. In USER part, we use the measurements of reference stations as those of users and estimate the corrected users' positions and protection levels (HPL, VPL). With the results of estimation, we analyzed the performance of the algorithms. We assured the estimated UDRE /GIVE values and the protection levels bound the corresponding errors effectively. In this research, we can expect the possible performance of WADGPS in Korea, and the developed modules will be useful to implementation and improvement of the algorithms.

• 재활복지
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• 제18권4호
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• pp.295-314
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• 2014

본 연구는 난청인이 오류를 보이는 음소들의 유형과 오류율을 확인하여 청능재활 현장에서 한국자음지각검사(KCPT)를 더욱 잘 활용할 수 있도록 기초자료를 제공하는데 목적이 있다. 30명의 감각신경성난청인을 대상으로, KCPT를 실시하여 오류유형, 화자에 따른 KCPT 점수의 변화 등을 알아보았다. 오류유형의 경우 30% 이상의 오류율을 보인 음소는 초성검사문항의 경우 /ㄷ/, /ㅂ/, /ㅃ/, /ㅉ/, /ㅌ/이었으며, /ㅊ/을 제외한 모든 음소에서 10% 이상의 오류율을 보였다. 종성검사문항에서 30% 이상의 오류율을 보인 음소는 /ㄱ/과 /ㄷ/ 이었다. 오류유형을 살펴보면 초성검사문항에서는 초성자음대치, 종성검사문항에서는 종성자음대치가 가장 많은 것으로 나타났으며, 각 검사문항이 초성 및 종성에 대한 검사에 적절한 도구임을 확인하였다. 또한 KCPT를 발화하는 화자가 남성 또는 여성으로 바뀌어도 점수에는 유의한 차이를 보이지 않는 것으로 나타나서 재활현장에서 화자의 성별에 관계없이 KCPT를 활용할 수 있음을 확인하였다.

• 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.

• 한방재활의학과학회지
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• 제28권2호
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• pp.47-60
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• 2018

Objectives The objective of this study was to investigate the effect of Anti-condensing on the composition of ChondroT Methods Specimens are divided in 7 groups (Control, ChondroT, Lonicerae Folium (Gumenhwa, GEH), Angelicae Gigantis Radix(Danggui, DG), Phellodendri Cortex(HwangBaek, HB), Osterici Radix(Kanghwal, KH), Clematidis Radix(Weeryungsun, WRS)) Each specimen is subjected to a concentration of 20 %, 10 %, and 5 %, and is administered to collagen and thrombin-stimulated platelets. Results In the anticoagulance effect test, Lonicerae Folium and ChondroT very well. The effect was high in order of Lonicerae Folium-Angelicae Gigantis-Phellodendri Cortex-Osterici Radix and Clematidis Radix. Conclusions ChondroT has anti-condensing effects on blood platelet.

• 전자공학회논문지SC
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• 제45권5호
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• pp.13-20
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• 2008

청력 손실을 보상하고 난청인이 다른 사람들과 대화할 수 있도록 디지털 보청기 알고리즘은 개발 되어 왔음에도 불구하고, 디지털 보청기 사용자들은 음성을 듣는데 어려움이 있다고 불만을 토로한다. 그 이유는 피드백이나 잔여 노이즈 등에 의해 디지털 보청기를 통한 음성의 질이 이해하기에 불충분하기 때문이다. 또 다른 이유로 포먼트들 사이에서 일어나는 마스킹 현상이 될 수 있다. 이 연구에서 정상 청각 피험자와 노인성 난청을 갖고 있는 난청인 피험자의 마스킹 특성을 측정하여 음성에서의 마스킹에 의한 음성 인지 저하를 확인하기 위한 실험을 하였다. 실험은 순음검사, 어음 청취 역치 검사, 낱말 분별력 검사, 수음 마스킹 검사, 어음 마스킹 검사의 5개 테스트로 이루어졌다. 어음 마스킹 검사에서 각각 어음 세트에 25개의 어음이 사용되었다. 각 어음의 왜곡을 객관적으로 평가하기 위해서 log likelihood ratio (LLR)를 도입하였다. 결과적으로 포먼트 향상의 양을 늘리면 늘릴수록 어음 인지는 낮아졌고, 각 어음 세트에서 각각의 향상된 어음은 통계적으로 비슷한 LLR을 갖지만 어음인지는 그렇지 않게 나타났다. 이것은 왜곡이 아닌 음향 마스킹이 어음 인지에 영향을 준다는 것을 의미한다. 실제로 피험자들 대부분이 맞추지 못한 음성을 주파수 분석한 결과 첫 번째와 두 번째 포먼트 사이의 레벨 차이가 약 35dB이며 이는 순음 마스킹 실험 결과(정상 청각 피험자:36.36dB, 난청인 피험자:32.86dB)와 비슷한 양상을 보였다. 실험 결과에서 볼 수 있듯이 음향 마스킹의 특성은 정상 청각인과 난청인 사이에서 다르게 나타난다. 그렇기 때문에 보청기 착용 전 마스킹 특성을 검사하고, 피팅 시에 적용해야 한다.