• 대한인간공학회지
• /
• 제34권3호
• /
• pp.223-234
• /
• 2015

Objective:This study aims to investigate the correlation between office environment satisfaction levels and workers' subjective symptoms by conducting surveys asking office workers to state their subjective symptoms and office satisfaction levels. Background: The increased number of office workers and their work hours have led to new understandings of the importance of office environments including its temperature, humidity, noise levels, lighting, space arrangements, and quality of air. Method: Specific details on office work, office environment, office space satisfaction levels, workplace related symptoms, absence from work, due to workplace-related symptoms, were analyzed based on the survey answers given by 451 office workers who were the subjects of this research. Results: Office workers showed different characteristics of subjective symptoms depending on their gender, age, work experience, and time spent resting and on computers. Also, differences in symptoms were found for workers with different satisfaction levels for office environment (temperature, humidity, noise levels, quality of air, lighting) and office space arrangements (location of monitors, area and display of office space, chairs and desks). Conclusion and Application: Relationship between workers' satisfaction levels with the office environment and their subjective symptoms is expected to be serve as essential data for systematic management of the workplace.

• 한국정밀공학회지
• /
• 제9권2호
• /
• pp.128-137
• /
• 1992

An automatic noise detection system is developed to sense abnormal noises in operating a microwave electronic range. A noise detection method is presented which accounts for the effects of backgound and dynamic noises of the range. A recursive formula used as a noise estimator is a special case of the discrete-time Kalman filter in stochastic processes. Noise levels were measured using a noise acquisition processor in a closed room free of background noise, and detected signals were processes using a microcomputer. The results obtaines showed that the fault detection system should be fast in response to the data acquired and should be high in accuracy and reliability.

• 한국주거학회논문집
• /
• 제18권5호
• /
• pp.85-91
• /
• 2007

This is a case study for improving the sound environmental quality of cafeteria in university campus. The purpose of the study is to find out the present condition of physical level, type, and cause of indoor noise of cafeteria in university campus by comparison with a restaurant near campus. Research methods were field survey and questionnaire survey. Field survey was consisted of measurement on equivalent and instant noise level and observation on noise type. Respondents of questionnaire survey were 60 students using subject cafeteria or restaurant. Surveys were carried out in the 8th and in the 14th of December 2005. The results are as follows. 1) Indoor noise levels of the cafeteria were measured as $67.2{\sim}76.6$ (average 73.3) dB(A)Leq5min and $60.3{\sim}90.5$ (average 71.2) dB (A), exceeded the indoor noise recommended value of ASHRAE (American Society of Heating, Refrigerating and Air Conditioning Engineers). But noise levels of the restaurant were $61.6{\sim}70.4$ (average 66.9) dB(A)Leq5min and $59.8{\sim}70.6$ (average 64.9) dB(A). 2) The users's responses on major noise type in the cafeteria were 'noise by handling equipment and tableware', 'noise by moving chairs', and 'talcing noise', but 'taking noise' and 'background music' in the restaurant. 3) It was found that indoor noise level of the cafeteria was caused by sound reflection of finishing materials, noise diffusion by open type kitchen, and dragging noise of movable furniture.

• 한국음향학회지
• /
• 제42권6호
• /
• pp.617-626
• /
• 2023

개방형 사무실에서 소음과 스피치 프라이버시 문제는 꾸준히 제기되어 왔다. 이러한 개방형 사무실의 문제점을 해결하기 위한 마스킹 음원에 대한 연구가 필요하다. 따라서 본 연구에서는 청취 실험을 통하여, 쾌적한 물소리를 마스킹 음원으로 제안하고자 한다. 먼저 다양한 소음 레벨에 대하여 음환경 쾌적도와 스피치 프라이버시를 고려한 최적 물소리 레벨에 대하여 고찰하고자 한다. 이후 최적 레벨의 물소리 도입이 업무효율성에 미치는 영향을 검정하고자 한다. 청취실험에서 사용된 사무실 소음은 실제 개방형 사무실에서 바이노럴 마이크를 활용해 녹음하였고, 헤드폰을 통해 피험자들에게 제시하였다. 청취실험 음원은 각각 3개의 등가 배경소음레벨(55 dBA, 60 dBA, 65 dBA)과 5개의 신호대잡음비[Signal to noise ratio(SNR) -10 dB, -5 dB, 0 dB, +5 dB, +10 dB]의 조합로 구성하였고, 각 음원에 대한 주관평가로 전체적인 음환경 쾌적도(Overall Soundscape Quality, OSQ)와 듣기 어려운 정도(Listening Difficulty, LD)를 평가하였다. 평가 결과 배경음 보다 물소리가 커질수록 LD는 증가하였지만 OSQ는 감소하였다. 특히 물소리가 사무실 소음 보다 클경우 도입 전보다 OSQ가 감소하였다. 따라서 OSQ와 LD를 고려하였을 때 소음레벨별 최적 SNR은 모든 소음레벨에 대하여, -5 dB로 나타났다. 이후 업무 효율성을 평가하기 위하여, 최적 레벨의 물소리 도입 전후에 인지능력(Cognitive performance)을 평가하였다. 평가 결과 최적 레벨의 물소리를 도입할 경우, 배경소음이 55 dBA에서는 인지능력평가 결과가 물소리 도입 전에 비해 감소하는 것으로 나타났으나, 60 dBA와 65 dBA에서는 증가하는 것으로 나타났다.

• Journal of Audiology & Otology
• /
• 제25권4호
• /
• pp.171-177
• /
• 2021

Background and Objectives: The purpose of the present study was to validate the performance and diagnostic efficacy of the Korean digits-in-noise (K-DIN) test in comparison to the Korean speech perception-in-noise (K-SPIN) test, which is the representative speech-in-noise test in clinical practice. Subjects and Methods: Twenty-seven subjects (15 normal-hearing and 12 hearing-impaired listeners) participated. The recorded Korean 0-9 digits were used to form quasirandom digit triplets; 50 target digit triplets were presented at the most comfortable level of each subject while presenting speech-shaped background noise at various levels of signal-to-noise ratios (-12.5, -10, -5, or +5 dB). Subjects were then instructed to listen to both target and noise masker unilaterally and bilaterally through a headphone. K-SPIN test was also conducted using the same procedure as the K-DIN. After calculating their percent correct responses, K-DIN and K-SPIN results were compared using a Pearson-correlation test. Results: Results showed a statistically significant correlation between K-DIN and K-SPIN in all hearing conditions (left: r=0.814, p<0.001; right: r=0.788, p<0.001; bilateral: r=0.727, p<0.001). Moreover, the K-DIN test achieved better testing efficacy, shorter average listening time (5 min vs. 30 min), and easier performance of task according to participants' qualitative reports than the K-SPIN test. Conclusions: In this study, the Korean version of digit triplet test was validated in both normal-hearing and hearing-impaired listeners. The findings suggest that the K-DIN test can be used as a simple and time-efficient hearing-in-noise test in audiology clinics in Korea.

• 대한청각학회지
• /
• 제25권4호
• /
• pp.171-177
• /
• 2021

Background and Objectives: The purpose of the present study was to validate the performance and diagnostic efficacy of the Korean digits-in-noise (K-DIN) test in comparison to the Korean speech perception-in-noise (K-SPIN) test, which is the representative speech-in-noise test in clinical practice. Subjects and Methods: Twenty-seven subjects (15 normal-hearing and 12 hearing-impaired listeners) participated. The recorded Korean 0-9 digits were used to form quasirandom digit triplets; 50 target digit triplets were presented at the most comfortable level of each subject while presenting speech-shaped background noise at various levels of signal-to-noise ratios (-12.5, -10, -5, or +5 dB). Subjects were then instructed to listen to both target and noise masker unilaterally and bilaterally through a headphone. K-SPIN test was also conducted using the same procedure as the K-DIN. After calculating their percent correct responses, K-DIN and K-SPIN results were compared using a Pearson-correlation test. Results: Results showed a statistically significant correlation between K-DIN and K-SPIN in all hearing conditions (left: r=0.814, p<0.001; right: r=0.788, p<0.001; bilateral: r=0.727, p<0.001). Moreover, the K-DIN test achieved better testing efficacy, shorter average listening time (5 min vs. 30 min), and easier performance of task according to participants' qualitative reports than the K-SPIN test. Conclusions: In this study, the Korean version of digit triplet test was validated in both normal-hearing and hearing-impaired listeners. The findings suggest that the K-DIN test can be used as a simple and time-efficient hearing-in-noise test in audiology clinics in Korea.

• 한국음향학회지
• /
• 제43권2호
• /
• pp.162-167
• /
• 2024

풍력발전기에서 방사되는 저주파 소음은 가장 관심이 높은 불만족 사항 중의 하나이다. 이에 본 연구에서는 공학적으로 유용하게 사용할 수 있는 덴마크 모델과 ISO 9613에 기초한 상용 프로그램인 SoundPLAN과 ENPro에 의한 풍력발전기 저주파 소음 예측값들과 측정값을 비교함으로써 모델들에 대한 신뢰성을 살펴보았다. 육상에서 대표적인 3 MW급 풍력발전기를 대상으로 적용한 결과 주파수 12.5 Hz에서 80 Hz 범위에서 측정값과 예측값은 최대 5 dB 이내의 차이를 보였다. 이러한 원인으로는 대상 풍력발전기는 7년 이상 운영되었기 때문에 음향파워레벨의 변화가 생겼기 때문으로 추정할 수 있다. 하지만 저주파 대역에서 가장 정확하다고 할 수 있는 Boundary Element Method (BEM) 예측값과 다른 모델에 의한 예측값 그리고 측정값은 2.5 dB 이내로 잘 일치한 점을 고려할 때 본 연구 대상의 모델들은 3 dB 이내의 편차로 활용될 수 있을 것으로 기대된다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2003년도 추계학술대회논문집
• /
• pp.917-917
• /
• 2003

The auditory experiments based on the subjective annoyance responses were undertaken for the establishment of the adverb modifiers of the heavy-weight impact noises. The standard heavy weight impact noise, impact ball noise and adult walking noise were recorded by dummy head at a newly-built apartment and were presented to the subjects by headphones. The levels of the three impact noises were varied from 30 to 60㏈(A) and the subjects matched one of the adverb modifiers to each level of the noise sources. As a result, seven scale modifiers were established and the intervals between the modifiers were found as equal. In addition, it was found that the lower annoyance noise limits for the heavyweight impact, impact ball and walking were 40-45㏈ (L$\sub$I, Fmax. AW), which is 6㏈ lower than in the previous study. The background noise level was as low as 21㏈(A) in the test booth, therefore, the testing conditions need to be concerned for evaluation of floor impact noise.

• 한국산학기술학회논문지
• /
• 제13권5호
• /
• pp.2291-2297
• /
• 2012

X-선 스펙트럼 데이터는 물질의 성분과 관련이 없는 신호(백그라운드, 노이즈)들을 포함 하고 있다. XRF는 스펙트럼에서 가우시안 형태의 피크 위치와 크기를 이용하여 시료의 성분을 분석하며, 시료의 성분을 정확히 분석하기 위해서는 노이즈와 백그라운드를 제거 하여야 한다. 백그라운드를 제거하기 위한 방법으로는 SNIP, Threshold, Morphology 방법 등을 적용하고 있으며, Threshold 기법을 중에서 블록별로 각기 다른 임계값을 적용하는 Interval Threshold기법이 하나의 임계값을 적용하는 Level Threshold 방법보다 더 좋은 성능을 발휘한다. 본 논문에서는 Interval Threshold를 적용하기 위하여 웨이블릿을 이용하여 블록을 분리하는 알고리즘을 제안하였다.

• 한국멀티미디어학회논문지
• /
• 제20권8호
• /
• pp.1258-1270
• /
• 2017

'Semantic gap' has been a year-old problem in automatic video summarization, which refers to the gap between semantics implied in video summarization algorithms and what people actually infer from watching videos. Using the external EEG bio-feedback obtained from video watchers as a solution of this semantic gap problem has several another issues: First, how to define and measure noises against ERP waveforms as signals. Second, whether individual differences among subjects in terms of noise and SNR for conventional ERP studies using still images captured from videos are the same with those differently conceptualized and measured from videos. Third, whether individual differences of subjects by noise and SNR levels help to detect topic-irrelevant shots as signals which are not matched with subject's own semantic topical expectations (mis-match negativity at around 400m after stimulus on-sets). The result of repeated measures ANOVA test clearly shows a 2-way interaction effect between topic-relevance and noise level, implying that subjects of low noise level for video watching session are sensitive to topic-irrelevant visual shots, while showing another 3-way interaction among topic-relevance, noise and SNR levels, implying that subjects of high noise level are sensitive to topic-irrelevant visual shots only if they are of low SNR level.