• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.3 s.26
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• pp.193-199
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• 2006

The noise levels on board ship recognized at Europe in the early 1970s and the noise regulations on the ship began to put in a statutory form. After that, in 1982 'International Code on Noise Levels on Board Ships' adopted by IMO and it became a standards to the newly built ship and it remains up to recently. Especially, the ship engine room, which have huge main engine and various kinds of subsidiary machines, is under an extremely loud condition and so the worker who works in it is easy to lose his hearing. Recently, each nation regulates the allowable noise exposure time by law to protect the industrial employee from the occupational hardness of hearing. In our country, the allowable noise exposure time is regulated by the labor. standard law but the international provisions regulated by IMO have been applied in case of the ship engine room. In this paper, the cabin's noise levels of cargo-passenger ships plies south-west coast line were investigated.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.10
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• pp.8-13
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• 2009

The MF(matched filter) is the optimum signal detector that maximizes the output instantaneous signal power to average noise power ratio in white noise environment. But it cannot give the optimum detection performance if the background noise is not white. So, the whitening process preceding the matched filter is needed in the conventional detector which results in a PWMF(pre-whitening matched filter). Its performance is mainly affected by the estimation accuracy of non-white noise model which is used in the whitening procedure. To estimate more accurate model to improve performance, the computational complexity is increased. Therefore, a spectrum based detector which shows better performance than the PWMF under the similar complexity condition or less complexity under the similar performance condition is proposed in this paper. And its performance and complexity are analyzed and compared with the conventional PWMF.

• Journal of Oral Medicine and Pain
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• v.30 no.4
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• pp.427-432
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• 2005

This study have been compared and analyzed voice parameter under the condition of normal voice and auditory condition(noise and music) for 29 patients of orofacial pain and 31 normal people to investigate voice feature and vocal variation for auditory condition of orofacial pain patient. 1. Compared to normal voice, orofacial pain patient showed lower and unstable voice feature which has low F0 rate and high jitter and shimmer rate. 2. Voice of orofacial pain patient showed more relaxed and stable voice feature with low F0 and shimmer rate in the music condition than noise condition. 3. Normal people's voice has no significant difference between music and noise condition even though it has high F0 rate under the noise condition. As a result, orofacial pain patient showed difference of feature and different response for external auditory condition compared to normal voice. Providing of positive emotional environment such as music could be considered for better outcome of oral facial pain patient's functional disability.

• KIEAE Journal
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• v.4 no.3
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• pp.37-44
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• 2004

In this study, foreign and domestic noise criteria on walls, floors, and water supply facilities were reviewed and the results are as follows : regulation can be divided two things, one is on thickness the other is sound insulation performance. Green Building regulation based on the law and this have sound classification systems. Since these regulations are not established in Korea. The noise regulation on water supply-drain facilities and domestic guideline on interior noise level is needed. Foreign regulations are stricter than those of ours. And those has sound classification system for the better acoustic condition of inhabitants'.

• Journal of odor and indoor environment
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• v.17 no.4
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• pp.346-354
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• 2018

In this study, the condition of the hazardous materials in the bus was monitored according to the ventilation mode of the air conditioning system during bus service. The bus was surveyed using the indoor air quality measurement method of public transportation vehicles within one year of delivery. We evaluate the $CO_2$ and $PM_{10}$, which are the controlled parameters in buses by the Ministry of Environment, and VOCs and HCHO, the non-controlled parameters. The $PM_{10}$ concentration increased due to outdoor air intake; however the $CO_2$ concentration was found to decrease. In addition, the concentration of VOCs and HCHO was found to decrease due to the forced ventilation system and the outdoor air intake. These results show that the concentration of the other materials except $PM_{10}$ can be changed due to the outside air concentration and forced ventilation system. Therefore, through indoor air quality characteristics of the bus according to air condition system are intended to be used as the basis of an operation manual.

• Korean Journal of Health Education and Promotion
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• v.19 no.3
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• pp.107-120
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• 2002

There has been a rapid industrial progress in Korea since 1962 by the success of 5-year economic development plan, and the number of industrial work has also made a rapid increase. Consequently, the management of the occupational health for the purpose of promoting the health of industrial workers and improving the working environment is badly needed in these days. Health services on industrial noisy environment have been provided only for noise-induced hearing loss management until now. But gradually, modem diseases and death have come to be related to the stress and mental health, therefore noise-induced mental disorder, like a stress became very important. Thus, this study has been carried out to analyze the relationship between workers' stress symptoms and the perceived working environment and the perceived working conditions. This study included 786 industrial workers selected from II factories in Buchun. The results were as follows: 1. For demographic characteristics, most of the workers were males(75.7%), the 20～29 years old were 33.8% and those who graduated from high school were 56.1%. The workers whose monthly income ranged from 700,000 to 1,500,000 won were 37.9% and who has a religion were 49.0%. 2. For occupational characteristics, workers who had worked 5～10 years in the factories were 35.8%. Those who felt much for them workload were 42.7% and who worked more than 8 hours a day were 73.7%. Those who were dissatisfied with their pay and job were 51.1 % and 31.2%. The workers who responded ventilation condition of their worksites were bad were 50.4% and the dissatisfied with working environment of their worksites were 43.8%. 3. For the noise exposure level in worksite, workers who were exposed to 70∼90㏈ were 37.4%, 90∼100㏈ were 25.2% and 50∼70㏈ were 18.8%. 4. Workers∼ stress symptoms were significantly related to marital status and their monthly income(P〈0.05). Workers who were single and had lower monthly income showed higher PSI(Psychiatric Symptom Index) scores than those who were married and had higher monthly income. Higher PSI scores were also significantly related to the night-work, workload, dissatisfaction with their job, and bad relationship with their bosses or co-workers. 5. The higher noise exposure level in worksite from 80㏈ was, the more severe stress symptoms including PSI subparts were reported; Anxiety, Anger, Depression, and Cognitive disorder symptom(P〈0.001). 6. According to the results of stepwise multiple regression analysis, factors affecting workers' PSI scores were noise exposure level in worksite(R2=0.150), relationship with coworkers, amount of workload, monthly income and relationship with bosses orderly and the total R2 of this 6 factors was 29.7%.

• Journal of Broadcast Engineering
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• v.23 no.4
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• pp.511-518
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• 2018

This paper deals with improving speech intelligibility by applying binary mask to time-frequency units of speech in noise. The binary mask is set to "0" or "1" according to whether speech is dominant or noise is dominant by comparing signal-to-noise ratio with pre-defined threshold. Bayesian classifier trained with Gaussian mixture model is used to estimate the binary mask of each time-frequency signal. The binary mask based noise suppressor improves speech intelligibility only in noise condition which is included in the training data. In this paper, speaker adaptation techniques for speech recognition are applied to adapt the Gaussian mixture model to a new noise environment. Experiments with noise-corrupted speech are conducted to demonstrate the improvement of speech intelligibility by employing adaption techniques in a new noise environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.8
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• pp.1943-1950
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• 2015

Korean representative residence type is apartment house. Due to this, civil complaint related to living noise is rapidly increasing. Here, in case when they suffer from surrounding noise in daily life, they can raise civil complaint. However, in general home, it is difficult to measure noise utilizing expert equipment, in many cases they use smart phone app. Noise measurement app that was previously released has markedly low correctness, e.g. value is differently measured in the same condition, therefore, it is difficult to be used for the actual noise measurement. Therefore, this paper suggests mobile data process system for noise measurement of living environment utilizing smart phone. The expected effect of this research can be utilized as the civil complaint material by conveniently measuring the noise and presuming the direction that the noise appeared at the home that has no equipment.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.125-129
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• 2006

It is very important to remove the noise levels made by an electric home appliance and machines they are located in the auditory region. The noise of ship engine room is known as it is not easy to lower so the working environment of the engine room is the worst condition because the improvement for the noise seemed insignificant and the hearing loss is occurred. As the monitoring equipment and an intelligent control system are improved rapidly the main engine of the ship can be enclosed with an acoustic barrier and any other absorbtion equipment. In this study, the sound absorbtion barrier is experimentally researched by change the volume and the length of the neck for the Helmholtz resonator as the resonator can absorb the noise effectively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.862-869
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• 2006

The purpose of this study is to propose the proper vocabularies for evaluating H.D TV set fan noise in residential condition. To achieve this goal, psycho-acoustic experiments were carried out with TV set fan noise modulated at specific frequency band. finally, a correlation analysis between vocabularies, and a factor analysis of psycho-acoustical responses were conducted. As a result of this study, followings are suggested. Analyzing the psycho-acoustical response corresponding to the various sound level, the higher the sound levels, the higher the response values were. It is estimated that the sound level determined psycho-acoustical responses. On the degree of response to fan noise, the initial level of negative feeling is located on $35{\sim}40$ dB(A). The factor of evaluating H.D. TV set fan noise has induced three the appropriate korean adjectives; Irritate, Monotonous, stuffy and dryness. The result of this study may be used to evaluate the acoustic threshold level for indoor noise or a basis for specifying the desired acoustic environment of dwellings.