• Journal of environmental and Sanitary engineering
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• v.3 no.2 s.5
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• pp.43-60
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• 1988

This study was carried out to determine traffic noise level and analyze noise reduction effects of various sound protection facilities in the area of Seoul, Inch'on, Songchoo and Seoul- Busan Expressway from March to Octover, 1987. The results were as follows; 1. As compared with the environmental standards and the traffic noise level in heavy noise areas, traffic noise levels observed were shown in higher than environmental standards. The noise levels in Seoul were determined at 12.8-18.2 dB(A) in daytime and 19.0-26.9 dB (A) in nighttime. And incase of inch'on, it were 6.7-9.6 dB(A) in daytime, 7.9-18.9 dB(A) in nighttime, respectively. 2. The environmental noise level observed in the backside of protection facilities, such as apartment, soundproof barrier and houses, which were constructed in paralled to the road was lower about 3-5 dB(A) than perpendicular to theroad. Noise recuction effect of upper stairs in apartment was higher than lower stairs. 3. The predicted noise level obtained from the equation $({\triangle}L\;=\; -10\;log\;(^{I'1}/Ii)\;was\;\pm\;1dB$ (A) and the correlation coefficient (r) was 0.923. 4. The noise reduction effect in backside of apartment was measured at on sites and predicted by total noise loss equation. The predicted noise level was 60.9 dB(A) and the measured level was 60.6 dB(A), respectively. 5. The narrow width landscape less than 10m width was almost no effect for the protection of traffic noise. According to the synthesis of the above results, the noise level of the road was exceeding mostly the environmental standard in the heavy traffic areas. The counterplan should be set as well. The insulation of noise protection facilities were effective by the location with near distance from the road edge. The reduction effect of double window in apartment was represented so much. The prediction model could be applied to estimate the noise levels in the roadside as well as the effectiveness for the noise protection facilities.

• Journal of environmental and Sanitary engineering
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• v.17 no.2
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• pp.55-62
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• 2002

For my thesis I have analyzed the differences between the traffic noise level surrounding the schools and the perceived level of noise. 1 have used the ways of measurement and questionnaires to support my study. According to the analysis, the measured noise level was higher than the expected noise level. The equivalent noise level was proven to be higher when the windows of the classrooms were open. The noise level was also higher on the third floor than the first floor. The correlation between the measured noise level and the perceived level of noise was tested in each school. The school which had a higher expected noise level showed a high perceived level of noise. The measured noise level and the perceived level of noise became larger on the higher floors. Through the questionnaires, the traffic noises were proven to be the largest noise-making source surrounding the schools. Most of the students replied on the questionnaires that they have been consistently bothered by the noise. It interfered with their studies and concentration. Also, the sound of their voices became louder because of the noise around their schools. Therefore, I have come to the conclusion that the traffic noises that surround the schools give the students negative influences.

• KIEAE Journal
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• v.3 no.2
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• pp.33-36
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• 2003

The influence of the visual information on the sound perception would be considerable. Furthermore, if the sound perception ranges in noisiness or annoyance beyond the loudness, it will depend much more on the shape of the visual information. This paper aims to estimate the influence of the several kinds of visual information on the perception of road traffic noise by means of the psycho-acoustic test method. The findings of present study on the influence of visual information on subjective noise perception are summarized as follows: Presenting visual images of mild and comfortable scenery reduced the noise perception reaction at the less noisy environments not exceeding 65 dB(A). At highly noisy environments exceeding 65 dB(A), however, the noise perception can be reduced by strong image of waterfall. Even eliminating the road traffic image may be helpful. Visual image of waterfall reduced the noise perception at all levels. It is inferred that the road traffic noise perception can be effectively ameliorated by presenting strong and real landscape images at any noisy environment.

• The Journal of the Acoustical Society of Korea
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• v.12 no.3
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• pp.43-48
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• 1993

This study was carried out to verificate the possibility of using the laboratory setting psycho-acoustic experiment compared with the field and to delineate the appropriate indices in evaluating the Noisiness of road traffic noise by means of psycho-acoustic method. Reviewing the typical patterns of traffic noises depending upon the shapes ad conditions of the road, the road traffic noises in several representative points in the major residential areas in Kwangju city were recorded and reproduced with the noise levels modified in various steps. With these 20 sound sources, psycho-acoustic experiments in the laboratory were performed on 11 volunteer subjects. And then, psycho-acoustic experiments in the real field were performed on 10 volunteer subjects to compare the results of the laboratory experiment, the results are summerized as follows : 1. The psycho-acoustic experiments in the laboratory elicited the data well matching with those obtained in the field, resulting in even higher corelation levels. This indicates that the field assessement of responses to the noise can be replaced by the evaluatioin in the laboratory settings which render many variables easily controlled and that the responses of the residents to the noise can be easily predicted in the laboratory by applying this method. 2. Also among the complex indices, such as Noise Pollution Level or Annoyance Index high correlations were detected. On the other hand, low corelations were noted among Traffic Noise Index. 3. Highly significant correlations were found among the direct indices such as Leq, L\sub 10\, On the other hand, low correlations were detected among L\sub 50\.

• Journal of Environmental Health Sciences
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• v.30 no.3
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• pp.283-292
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• 2004

Valid evaluation of community reaction to road-traffic noise exposure is important for the policy making and quality of life. The purpose of this study is to evaluate the relationship between community reaction and nighttime road-traffic noise. The study measured nighttime roadside noise caused by high traffic which is greater than LAeq(22:00-07:00) 65dB(A) and lower than 65dB(A) at Chonju city, from March to April, 2003. Three hundred sixty seven subjects, aged from 20 to 65, were selected from those who are residing close to the major roads. They were asked to answer the questions regarding noise source, stress(PWI-SF), annoyance, disturbance of specific activity, disturbance of sleep, somatic symptom, and four suggested confounding factors. The relationship between annoyance, somatic symptom and noise exposure was not significant. Adjusted odds ratio(95% C.I.) for disturbance of communication　 and disturbance of attention and rest　 were 1.59(1.03-2.71), 1.64(1.06-2.81), respectively. On the other hand sleep disturbance　 was indicated as 1.34(0.77-2.32). The results suggested that federal policy-making about road-traffic noise should consider community reaction evaluated by various perspective including annoyance, disturbance of specific activity, disturbance of sleep, and confounding factors.

• Journal of Environmental Health Sciences
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• v.34 no.4
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• pp.311-315
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• 2008

This study was performed to investigate propagation characteristics and effects of road traffic noise generated from vehicles. Noise levels of expressway and general road were measured at four points in a straight line based on distance from the road, and analyzed. The average noise level of expressway was 78.9 dBA at 5 m, 76.4 dBA at 10 m, 72.0 dBA at 20 m, 69.0 dBA at 30 m. That of general road was lower about $3.1{\sim}3.5\;dBA$ than that of expressway. There was no significant difference in distance attenuation between expressway noise and general road noise. The farer the distance from source is, the more the attenuation is. The influence range of noise is assessed by noise environmental standards or road noise limits. Noise levels of the time zone were measured at a boundary line of apartment to grasp noise variation by time. The time zone of lowest noises was $3{\sim}4$ a.m. and that of highest noise was $8{\sim}10$ a.m. Data recorded on tapes were analyzed to understand the characteristics of frequency because these characteristics are important factors to plan the noise reduction measures, namely path measures.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.4
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• pp.89-97
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• 2004

동북아지역에서는 최근 산업화와 도시화로 인하여 많은 개발행위가 이루어져 왔으며, 그에 따라 개발과 환경적 결과와의 관계가 주목을 받기 시작했다. 선진국에서는 이미 이러한 관계에 있어 환경적요소가 의사결정단계에서부터 고려될 수 있도록 제도적 보완이 이루어져 왔으나 동 지역에서는 그간 이에 대한 대응이 미비했던 것이 사실이다. 이러한 관점에서, 동 연구는 동북아지역에서의 환경영향평가의 비교를 통한 상호 제도의 이해증진을 위해 수행되었다. 특히, 본 연구의 목적은 골프장 조성사업에 대한 환경영향평가를 수행함에 있어 중점평가항목과 운영 측면에서의 양국간 환경영향평가를 비교함으로써 향후 양국간에 월경성 환경협력 기반을 마련하는데 있다. 연구의 주요 결과는 첫째, 환경영향평가항목 측면에서 한국의 경우 지형 지질, 동 식물상, 토지이용, 수질, 토양, 소음 진동, 위락 경관, 교통 등8개의 중점평가 항목을 설정하여 다소 항목수가 많고 내용적으로는 체계와 형식을 중시하고 있는 반면, 중국의 경우에서는 지하수, 지표수, 생태계 등3개의 중점평가 항목을 설정하여 항목 수는 적으나 비교적 구체적이고 현실 상황을 잘 반영하고 있는 것으로 나타났다. 둘째, 운영상 측면에서 한국의 골프장 환경영향평가서는 수질, 생태계 훼손 등을 강조하고 있는 반면, 중국은 도로사면 훼손, 경관, 수질 등에 초점을 두고 있어 양국의 골프장 조성에 있어 환경에 미치는 주요영향 요소선정에 차이가 있는 것으로 나타났다.

• International Journal of Highway Engineering
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• v.17 no.6
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• pp.11-18
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• 2015

PURPOSES : The purpose of this thesis is to evaluate the effectiveness of an active noise cancellation (ANC) system in reducing the traffic noise level against frequencies from the predictive model developed by previous research. The predictive model is based on ISO 9613-2 standards using the Noble close proximity (NCPX) method and the pass-by method. This means that the use of these standards is a powerful tool for analyzing the traffic noise level because of the strengths of these methods. Traffic noise analysis was performed based on digital signal processing (DSP) for detecting traffic noise with the pass-by method at the test site. METHODS : There are several analysis methods, which are generally divided into three different types, available to evaluate traffic noise predictive models. The first method uses the classification standard of 12 vehicle types. The second method is based on a standard of four vehicle types. The third method is founded on 5 types of vehicles, which are different from the types used by the second method. This means that the second method not only consolidates 12 vehicle types into only four types, but also that the results of the noise analysis of the total traffic volume are reflected in a comparison analysis of the three types of methods. The constant percent bandwidth (CPB) analysis was used to identify the properties of different frequencies in the frequency analysis. A-weighting was applied to the DSP and to the transformation process from analog to digital signal. The root mean squared error (RMSE) was applied to compare and evaluate the predictive model results of the three analysis methods. RESULTS : The result derived from the third method, based on the classification standard of 5 vehicle types, shows the smallest values of RMSE and max and min error. However, it does not have the reduction properties of a predictive model. To evaluate the predictive model of an ANC system, a reduction analysis of the total sound pressure level (TSPL), dB(A), was conducted. As a result, the analysis based on the third method has the smallest value of RMSE and max error. The effect of traffic noise reduction was the greatest value of the types of analysis in this research. CONCLUSIONS : From the results of the error analysis, the application method for categorizing vehicle types related to the 12-vehicle classification based on previous research is appropriate to the ANC system. However, the performance of a predictive model on an ANC system is up to a value of traffic noise reduction. By the same token, the most appropriate method that influences the maximum reduction effect is found in the third method of traffic analysis. This method has a value of traffic noise reduction of 31.28 dB(A). In conclusion, research for detecting the friction noise between a tire and the road surface for the 12 vehicle types needs to be conducted to authentically demonstrate an ANC system in the Republic of Korea.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.5
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• pp.48-56
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• 2009

Regulation of Visible Light Transmission Percentage (VLT%) has been argued because it was known that the degree of darkness of tinted vehicle can affect to driving maneuver. Previously, it was proven that low level of VLT affects capacity reduction. But, due to lack of field data they could not analyze the effect of Car-Following model parameters. This study focuses on the effect of a tinted vehicle on following traffic flow. RTK GPS receiving data through field experiment analyzed based on headway distance, acceleration noise, sensitivity, and reaction time. As a result of analysis through GM 1st Model and 3rd Model, influence of following vehicle vary inversely with VLT and risk according as tinting of lead vehicle is third vehicle bigger than second vehicle. Also the results patterns of GM 3rd model include distance-headway are same with GM 1st Model. In the further need to research for influence analysis of traffic flow stability by the level of VLT.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1972.03a
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• pp.7-8
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• 1972

The effects of noise exposure are of two types: Nonauditory effects and auditory effects. Nonauditory effects of noise exposure are interference with communication by speech, sleeping and emotional behavior. The noise will cause the high blood pressure and rapid pulse, also that decrease the salivation and gastric juice. in experimentaly showed that the Corticoid hormon: Gonatotropic hormone were decrease and Thyrotropic hormoone is increase. Auditory effect of noise exposure. when the normal ear is exposed to noise at noise at hamful intensities (above 90㏈) for sufficiently long periods of time, a temoral depression of hearing results, disappearing after minutes or hours of rest. When the exposure longer or intesity greater is reached the Permanent threshold shift called noise-induced hearing loss. Hearing loss resulting from noise exposure presents legal as well as medical problems. The otologist who examines and evaluates the industrial hearing loss cases must be properly informed, not only concerning the otologic but also about the physical and legal aspects of the problems. The measurement of hearing ability is the most important part of a hearing conservation, both preplacement and periodic follow-up tests of hearing. The ideal hearing conservation program would be able to reduce or eliminate the hazardous noise at its source or by acoustic isolation of noisy working area and two ear protections (plugs and muff type) were developed for personal protection.